/* ========================================
   编图笔记 — Swiss Modernism 2.0
   Design System: Editorial black + clean grid
   Philosophy: Rational, international, minimal
   Reference: Swiss Design / Linear / Vercel
   ======================================== */

/* ========================================
   CSS Custom Properties — Design Tokens
   Swiss Modernism: neutral + accent pink
   ======================================== */
:root {
    /* === Brand — Editorial Black === */
    --color-primary: #18181B;
    --color-primary-hover: #27272A;
    --color-primary-soft: #F4F4F5;
    --color-primary-muted: #E4E4E7;

    /* === Accent — Orange (matches article inner pages) === */
    --color-accent: #FF6600;
    --color-accent-hover: #E55A00;
    --color-accent-soft: #FFF4E6;
    --color-accent-muted: #FFD9B3;

    /* === Surfaces — Clean neutral === */
    --color-bg: #FAFAFA;
    --color-bg-raised: #F5F5F5;
    --color-surface: #FFFFFF;
    --color-surface-hover: #FAFAFA;
    --color-surface-alt: #F9FAFB;

    /* === Borders === */
    --color-border: #E4E4E7;
    --color-border-hover: #D4D4D8;
    --color-border-focus: #18181B;

    /* === Text — High contrast black-gray === */
    --color-text: #09090B;
    --color-text-secondary: #52525B;
    --color-text-tertiary: #A1A1AA;
    --color-text-on-primary: #FFFFFF;
    --color-text-inverse: #18181B;
    --color-text-inverse-fg: #FAFAFA;
    --color-stat-bg: #18181B;
    --color-stat-fg: #FAFAFA;

    /* === Code === */
    --color-code-bg: #18181B;
    --color-code-text: #E4E4E7;
    --color-code-inline-bg: #F4F4F5;
    --color-code-inline-text: #BE185D;
    --color-code-border: #27272A;

    /* === Status === */
    --color-success: #16A34A;
    --color-success-soft: #F0FDF4;
    --color-error: #DC2626;
    --color-error-soft: #FEF2F2;
    --color-warning: #EA580C;
    --color-warning-soft: #FFF7ED;

    /* === Shadows — Subtle, layered === */
    --shadow-xs: 0 1px 2px rgb(0 0 0 / 0.04);
    --shadow-sm: 0 1px 3px rgb(0 0 0 / 0.06), 0 1px 2px rgb(0 0 0 / 0.04);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.06), 0 2px 4px -2px rgb(0 0 0 / 0.04);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.06), 0 4px 6px -4px rgb(0 0 0 / 0.04);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.08), 0 8px 10px -6px rgb(0 0 0 / 0.04);
    --shadow-card-hover: 0 0 0 1px rgb(0 0 0 / 0.08), 0 12px 24px -8px rgb(0 0 0 / 0.12);

    /* === Radius — Clean, geometric === */
    --radius-xs: 4px;
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 16px;
    --radius-2xl: 24px;
    --radius-full: 9999px;

    /* === Spacing — 4px base grid === */
    --space-1: 4px;    --space-2: 8px;    --space-3: 12px;
    --space-4: 16px;   --space-5: 20px;   --space-6: 24px;
    --space-7: 32px;   --space-8: 40px;   --space-9: 48px;
    --space-10: 64px;  --space-11: 80px;  --space-12: 96px;
    --space-14: 128px;

    /* === Layout === */
    --nav-height: 56px;
    --content-width: 680px;
    --wide-width: 960px;
    --sidebar-width: 220px;

    /* === Typography — Inter === */
    --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
    --font-mono: "JetBrains Mono", "Fira Code", "Cascadia Code", "Consolas", "SF Mono", "Monaco", monospace;

    --text-xs: 0.75rem;     --text-sm: 0.8125rem;
    --text-base: 0.9375rem; --text-lg: 1.0625rem;
    --text-xl: 1.25rem;     --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;   --text-4xl: 2.25rem;
    --text-5xl: 3rem;

    --leading-tight: 1.2;   --leading-snug: 1.35;
    --leading-normal: 1.6;  --leading-relaxed: 1.7;

    --weight-normal: 400;   --weight-medium: 500;
    --weight-semibold: 600; --weight-bold: 700;
    --weight-extrabold: 800;

    /* === Transitions === */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
    --duration-fast: 150ms;
    --duration-base: 200ms;
    --duration-slow: 300ms;
    --duration-glacial: 500ms;

    /* === Reading === */
    --progress: 0%;
}

/* ========================================
   Dark Mode — Deep charcoal
   ======================================== */
.dark {
    --color-primary: #FAFAFA;
    --color-primary-hover: #E4E4E7;
    --color-primary-soft: #27272A;
    --color-primary-muted: #3F3F46;
    --color-accent: #FF8A33;
    --color-accent-hover: #FFA866;
    --color-accent-soft: #2A1505;
    --color-accent-muted: #5C2A0A;
    --color-bg: #09090B;
    --color-bg-raised: #18181B;
    --color-surface: #18181B;
    --color-surface-hover: #27272A;
    --color-surface-alt: #18181B;
    --color-border: #27272A;
    --color-border-hover: #3F3F46;
    --color-border-focus: #FAFAFA;
    --color-text: #FAFAFA;
    --color-text-secondary: #A1A1AA;
    --color-text-tertiary: #71717A;
    --color-text-inverse: #FAFAFA;
    --color-text-inverse-fg: #09090B;
    --color-stat-bg: #18181B;
    --color-stat-fg: #FAFAFA;
    --color-code-bg: #09090B;
    --color-code-text: #E4E4E7;
    --color-code-inline-bg: #27272A;
    --color-code-inline-text: #F9A8D4;
    --color-code-border: #27272A;
    --shadow-xs: 0 1px 2px rgb(0 0 0 / 0.3);
    --shadow-sm: 0 1px 3px rgb(0 0 0 / 0.4);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.4);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.5);
    --shadow-card-hover: 0 0 0 1px rgb(255 255 255 / 0.1), 0 12px 24px -8px rgb(0 0 0 / 0.5);
}

/* ========================================
   Reset & Base
   ======================================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

:focus-visible {
    outline: 2px solid var(--color-text);
    outline-offset: 2px;
    border-radius: var(--radius-xs);
}
:focus:not(:focus-visible) { outline: none; }

::selection {
    background: var(--color-accent-muted);
    color: var(--color-text);
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: var(--leading-normal);
    color: var(--color-text);
    background: var(--color-bg);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    transition: background var(--duration-slow) var(--ease-out);
}

a { color: inherit; text-decoration: none; }
img, svg { max-width: 100%; display: block; }
button { cursor: pointer; font-family: inherit; border: none; background: none; }
input, select, textarea { font-family: inherit; font-size: inherit; }

/* Custom scrollbar */
::-webkit-scrollbar { width: 6px; height: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--color-border-hover); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--color-text-tertiary); }

@media print {
    .navbar, .footer, .back-to-top, .reading-progress { display: none !important; }
    body { background: #fff; color: #000; font-size: 12pt; }
    .article-content { max-width: 100%; }
}

/* ========================================
   Skip Link — Accessibility
   ======================================== */
.skip-link {
    position: fixed;
    top: -100%;
    left: var(--space-4);
    z-index: 10000;
    padding: var(--space-2) var(--space-4);
    background: var(--color-text);
    color: var(--color-bg);
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    border-radius: var(--radius-sm);
    text-decoration: none;
    transition: top var(--duration-fast);
}
.skip-link:focus {
    top: var(--space-2);
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

/* ========================================
   Reading Progress Bar
   ======================================== */
.reading-progress {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 2px;
    z-index: 200;
    pointer-events: none;
    background: transparent;
}
.reading-progress::after {
    content: '';
    position: absolute;
    top: 0; left: 0;
    height: 100%;
    width: var(--progress);
    background: var(--color-accent);
    transition: width 60ms linear;
}

/* ========================================
   Navigation — Clean, minimal
   ======================================== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgb(250 250 250 / 0.85);
    -webkit-backdrop-filter: saturate(180%) blur(16px);
    backdrop-filter: saturate(180%) blur(16px);
    border-bottom: 1px solid var(--color-border);
    transition: background var(--duration-base);
}
.navbar.scrolled {
    background: rgb(250 250 250 / 0.95);
    box-shadow: var(--shadow-xs);
}
.dark .navbar {
    background: rgb(9 9 11 / 0.85);
}
.dark .navbar.scrolled {
    background: rgb(9 9 11 / 0.95);
    box-shadow: 0 1px 3px rgb(0 0 0 / 0.5);
}

.navbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--nav-height);
    max-width: var(--wide-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

/* Logo — Clean geometric */
.logo {
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    letter-spacing: -0.03em;
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: var(--space-2);
    transition: opacity var(--duration-fast);
}
.logo:hover { opacity: 0.7; }
.logo-icon {
    width: 30px; height: 30px;
    background: linear-gradient(135deg, #FF6600 0%, #E55A00 100%);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: #FFFFFF;
    font-size: 14px;
    font-weight: var(--weight-extrabold);
    transition: transform var(--duration-base) var(--ease-out);
}
.logo:hover .logo-icon { transform: scale(1.05); }

/* Nav Links */
.nav-links { display: flex; align-items: center; gap: var(--space-1); }
.nav-links a {
    padding: 6px 14px;
    border-radius: var(--radius-sm);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    transition: all var(--duration-fast);
}
.nav-links a:hover { color: var(--color-text); background: var(--color-bg-raised); }
.nav-links a.active {
    color: var(--color-text);
    background: var(--color-primary-soft);
    font-weight: var(--weight-semibold);
}

.nav-actions { display: flex; align-items: center; gap: var(--space-2); }

/* Theme Toggle */
.theme-toggle {
    width: 34px; height: 34px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    color: var(--color-text-secondary);
    transition: all var(--duration-fast);
}
.theme-toggle:hover { color: var(--color-text); background: var(--color-bg-raised); }
.theme-toggle:active { transform: scale(0.92); }

/* Mobile Menu Button */
.mobile-menu-btn {
    display: none;
    flex-direction: column;
    gap: 4px;
    width: 34px; height: 34px;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    padding: 0;
}
.mobile-menu-btn:hover { background: var(--color-bg-raised); }
.mobile-menu-btn span {
    width: 18px; height: 2px;
    background: var(--color-text);
    border-radius: 1px;
    transition: transform var(--duration-base), opacity var(--duration-fast);
}

/* ========================================
   Hero — Modern blog style, orange as accent (not banner)
   ======================================== */
.hero {
    padding: var(--space-14) 0 var(--space-12);
    text-align: center;
    position: relative;
    overflow: hidden;
    background: var(--color-bg-raised);
}
.dark .hero {
    background: var(--color-bg);
}
/* subtle orange glow behind hero */
.hero::before {
    content: '';
    position: absolute;
    top: 40%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 720px;
    height: 720px;
    background: radial-gradient(circle, rgba(255, 102, 0, 0.08) 0%, transparent 60%);
    pointer-events: none;
    z-index: 0;
}
.hero-inner {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
    position: relative;
    z-index: 1;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: 4px 14px;
    background: var(--color-accent-soft);
    color: var(--color-accent);
    border: 1px solid var(--color-accent-muted);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    margin-bottom: var(--space-6);
    transition: all var(--duration-base);
}
.hero-badge:hover { background: var(--color-accent-muted); }
.hero-badge-dot {
    width: 5px; height: 5px;
    border-radius: 50%;
    background: var(--color-accent);
    animation: pulse-dot 2s ease-in-out infinite;
}
@keyframes pulse-dot {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

.hero-title {
    font-size: clamp(2.5rem, 7vw, 3.5rem);
    font-weight: var(--weight-extrabold);
    letter-spacing: -0.05em;
    line-height: 1.05;
    margin-bottom: var(--space-4);
    color: var(--color-text);
}
.hero-title::after {
    content: '';
    display: block;
    width: 64px;
    height: 4px;
    background: linear-gradient(90deg, #FF6600, #E55A00);
    margin: var(--space-5) auto var(--space-6);
    border-radius: 2px;
}

.hero-subtitle {
    font-size: var(--text-lg);
    color: var(--color-text-secondary);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-8);
    max-width: 500px;
    margin-left: auto; margin-right: auto;
}

/* Search Box — neutral surface, orange focus + button */
.search-wrapper { max-width: 520px; margin: 0 auto; }
.search-box {
    display: flex;
    align-items: center;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 4px;
    transition: all var(--duration-base) var(--ease-out);
    box-shadow: var(--shadow-xs);
}
.search-box:focus-within {
    border-color: var(--color-accent);
    box-shadow: 0 0 0 4px rgba(255, 102, 0, 0.1);
}
.search-box input {
    flex: 1;
    border: none;
    background: transparent;
    padding: 10px var(--space-4);
    font-size: var(--text-sm);
    color: var(--color-text);
    outline: none;
    min-width: 0;
}
.search-box input::placeholder { color: var(--color-text-tertiary); }
.search-box-btn {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: 10px 20px;
    background: linear-gradient(135deg, #FF6600 0%, #E55A00 100%);
    color: #FFFFFF;
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    transition: opacity var(--duration-fast);
}
.search-box-btn:hover { opacity: 0.9; }
.search-box-btn:active { transform: scale(0.97); }
.search-box-shortcut {
    display: flex; align-items: center;
    font-size: var(--text-xs); opacity: 0.5; font-weight: var(--weight-normal);
    color: var(--color-text-tertiary);
}
.search-box-shortcut kbd {
    font-family: var(--font-mono);
    background: var(--color-bg-raised);
    color: var(--color-text-secondary);
    padding: 2px 6px; border-radius: 3px; font-size: 10px;
}

/* ========================================
   Container & Layout
   ======================================== */
.container {
    max-width: var(--wide-width);
    width: 100%;
    margin: 0 auto;
    padding: 0 var(--space-6);
    box-sizing: border-box;
}
.container-narrow {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

/* ========================================
   Sections — Varied rhythm, not uniform
   ======================================== */
.section { margin-bottom: var(--space-10); }
.section-first { padding-top: var(--space-8); }
.section-last { margin-bottom: var(--space-8); }
.section-header {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    margin-bottom: var(--space-6);
}
.section-title {
    font-size: var(--text-xl);
    font-weight: var(--weight-bold);
    letter-spacing: -0.03em;
    color: var(--color-text);
}
.section-subtitle {
    font-size: var(--text-sm);
    color: var(--color-text-tertiary);
    margin-top: 2px;
}
.section-more {
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    color: var(--color-accent);
    display: flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    transition: all var(--duration-base) var(--ease-out);
}
.section-more:hover {
    gap: var(--space-3);
    background: var(--color-accent-soft);
    color: var(--color-accent-hover);
}
/* Alternating section accent — thin rule above certain sections */
.section-accent {
    position: relative;
    padding-top: var(--space-8);
}
.section-accent::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 40px; height: 1px;
    background: var(--color-accent-muted);
}

/* ========================================
   Article Cards — Varied masonry-style grid
   ======================================== */
.articles-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-5);
}

/* Cards have uniform heights */
.articles-grid .article-card:nth-child(1),
.articles-grid .article-card:nth-child(2),
.articles-grid .article-card:nth-child(3),
.articles-grid .article-card:nth-child(4),
.articles-grid .article-card:nth-child(5),
.articles-grid .article-card:nth-child(6),
.articles-grid .article-card:nth-child(7),
.articles-grid .article-card:nth-child(8),
.articles-grid .article-card:nth-child(9) { grid-row: span 1; }

/* 2 columns on all screens */
@media (min-width: 1100px) {
    .articles-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.article-card {
    position: relative;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
    transition: all var(--duration-base) var(--ease-out);
    display: flex;
    flex-direction: column;
    height: 260px;
    box-sizing: border-box;
}
.article-card:hover {
    border-color: var(--color-border-hover);
    box-shadow: var(--shadow-card-hover);
    transform: translateY(-2px);
}

.article-card-category {
    display: inline-flex;
    align-items: center;
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    color: var(--color-accent);
    letter-spacing: 0.03em;
    margin-bottom: var(--space-4);
    background: var(--color-accent-soft);
    padding: 3px 10px;
    border-radius: var(--radius-xs);
    align-self: flex-start;
    text-transform: uppercase;
}

.article-card-title {
    font-size: var(--text-lg);
    font-weight: var(--weight-semibold);
    line-height: var(--leading-snug);
    letter-spacing: -0.02em;
    margin-bottom: var(--space-3);
    color: var(--color-text);
}
.article-card-title a { color: inherit; text-decoration: none; }
.article-card:hover .article-card-title { color: var(--color-text); }

.article-card-excerpt {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-5);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    flex: 1;
}

.article-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: var(--space-4);
    border-top: 1px solid var(--color-border);
}
.article-card-meta {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    font-family: var(--font-mono);
}
.article-card-meta span { display: flex; align-items: center; gap: var(--space-1); }
.article-card-meta svg { width: 12px; height: 12px; opacity: 0.4; }
.article-card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 4px 8px;
}

/* ========================================
   Tag Component
   ======================================== */
.tag {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0 9px;
    border-radius: var(--radius-xs);
    font-size: var(--text-xs);
    font-weight: var(--weight-medium);
    font-family: var(--font-mono);
    background: var(--color-bg-raised);
    color: var(--color-text-tertiary);
    transition: all var(--duration-fast);
    white-space: nowrap;
    min-width: 50px;
    height: 24px;
    box-sizing: border-box;
    line-height: 24px;
}
.tag:hover { background: var(--color-accent-soft); color: var(--color-accent); }
.tag-primary { background: var(--color-accent-soft); color: var(--color-accent); }

/* ========================================
   Category Cards — Flowing pill row
   ======================================== */
.categories-grid {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
    justify-content: center;
}
.category-card {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    transition: all var(--duration-base) var(--ease-out);
    font-size: var(--text-sm);
}
.category-card:hover {
    border-color: var(--color-accent-muted);
    background: var(--color-accent-soft);
    transform: translateY(-1px);
    box-shadow: var(--shadow-sm);
}
.category-icon-box {
    width: 28px; height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--color-bg-raised);
    flex-shrink: 0;
    transition: transform var(--duration-base) var(--ease-out);
}
.category-card:hover .category-icon-box { transform: scale(1.1); }
.category-icon-box svg { width: 18px; height: 18px; }
.category-name {
    font-weight: var(--weight-medium);
    color: var(--color-text);
}
.category-count {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    font-family: var(--font-mono);
    margin-left: var(--space-1);
}

/* ========================================
   Article List (List Page) — Clean typographic rows
   ======================================== */
.articles-list { display: flex; flex-direction: column; gap: var(--space-3); }

.article-list-card {
    display: flex;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5) var(--space-6);
    transition: all var(--duration-base) var(--ease-out);
}
.article-list-card:hover {
    border-color: var(--color-border-hover);
    box-shadow: var(--shadow-md);
    transform: translateY(-1px);
}

.article-list-body {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.article-list-meta-row {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-size: var(--text-xs);
    font-family: var(--font-mono);
    color: var(--color-text-tertiary);
    flex-wrap: wrap;
}
.article-list-category {
    display: inline-flex;
    padding: 1px 8px;
    background: var(--color-accent-soft);
    color: var(--color-accent);
    border-radius: var(--radius-full);
    font-weight: var(--weight-medium);
    font-family: var(--font-sans);
    font-size: var(--text-xs);
    white-space: nowrap;
}
.article-list-date,
.article-list-time {
    display: inline-flex;
    align-items: center;
    white-space: nowrap;
}
.article-list-date::before {
    content: '';
    display: inline-block;
    width: 3px; height: 3px;
    background: var(--color-text-tertiary);
    border-radius: 50%;
    margin-right: var(--space-2);
    opacity: 0.5;
}
.article-list-time::before {
    content: '';
    display: inline-block;
    width: 3px; height: 3px;
    background: var(--color-text-tertiary);
    border-radius: 50%;
    margin-right: var(--space-2);
    opacity: 0.5;
}

.article-list-title {
    font-size: var(--text-lg);
    font-weight: var(--weight-semibold);
    line-height: var(--leading-snug);
    letter-spacing: -0.02em;
    color: var(--color-text);
}
.article-list-title a {
    color: inherit;
    text-decoration: none;
    transition: color var(--duration-fast);
}
.article-list-card:hover .article-list-title { color: var(--color-accent); }

.article-list-excerpt {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    line-height: var(--leading-relaxed);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* ========================================
   Page Header — Clean, centered
   ======================================== */
.page-header {
    text-align: center;
    padding: var(--space-10) 0 var(--space-6);
}
.page-title {
    font-size: var(--text-3xl);
    font-weight: var(--weight-extrabold);
    letter-spacing: -0.04em;
    line-height: 1.15;
    margin-bottom: var(--space-3);
    color: var(--color-text);
}
.page-subtitle {
    font-size: var(--text-base);
    color: var(--color-text-secondary);
    max-width: 480px;
    margin: 0 auto;
}
.page-header::after {
    content: '';
    display: block;
    width: 32px; height: 2px;
    margin: var(--space-4) auto 0;
    background: var(--color-accent);
    border-radius: 1px;
}

/* ========================================
   Filters — Clean pill tabs
   ======================================== */
.filter-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--space-4);
    margin-bottom: var(--space-6);
    flex-wrap: wrap;
}
.filter-tabs {
    display: flex;
    gap: var(--space-1);
    padding: 4px;
    background: var(--color-bg-raised);
    border-radius: var(--radius-md);
    flex-wrap: wrap;
}
.filter-tab {
    padding: 6px 16px;
    border-radius: var(--radius-sm);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    transition: all var(--duration-fast);
    white-space: nowrap;
}
.filter-tab:hover { color: var(--color-text); }
.filter-tab.active {
    background: var(--color-surface);
    color: var(--color-text);
    box-shadow: var(--shadow-xs);
    font-weight: var(--weight-semibold);
}
.filter-sort select {
    padding: 6px 16px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-surface);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    cursor: pointer;
    outline: none;
    transition: border-color var(--duration-fast);
}
.filter-sort select:focus { border-color: var(--color-border-focus); }

/* ========================================
   Article Detail — Refined reading layout
   ======================================== */
.article-detail-wrapper {
    display: flex;
    gap: var(--space-8);
    max-width: var(--wide-width);
    margin: 0 auto;
    padding: var(--space-7) var(--space-6) var(--space-10);
    position: relative;
}
.article-main {
    flex: 1; min-width: 0;
    max-width: var(--content-width);
    margin: 0 auto;
}

/* TOC Sidebar */
.article-toc-sidebar {
    display: none;
    position: sticky;
    top: calc(var(--nav-height) + var(--space-5));
    width: var(--sidebar-width);
    flex-shrink: 0;
    align-self: flex-start;
    max-height: calc(100vh - var(--nav-height) - var(--space-8));
    overflow-y: auto;
    padding-top: var(--space-4);
}
.article-toc-sidebar nav {
    border-left: 1px solid var(--color-border);
    padding-left: var(--space-4);
}
.article-toc-sidebar .toc-title {
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-text-tertiary);
    margin-bottom: var(--space-3);
}
.article-toc-sidebar .toc-group {
    margin-bottom: var(--space-4);
}
.article-toc-sidebar .toc-group > .toc-link {
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    color: var(--color-text-secondary);
    display: flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-1) 0;
    cursor: pointer;
}
.article-toc-sidebar .toc-group > .toc-link:hover { color: var(--color-accent); }
.article-toc-sidebar .toc-group > .toc-link::before {
    content: '▸';
    font-size: 10px;
    transition: transform var(--duration-fast);
}
.article-toc-sidebar .toc-group.open > .toc-link::before { transform: rotate(90deg); }
.article-toc-sidebar .toc-children {
    display: none;
    padding-left: var(--space-4);
    margin-top: var(--space-1);
}
.article-toc-sidebar .toc-group.open > .toc-children { display: block; }
.article-toc-sidebar .toc-children a {
    display: block;
    padding: 3px 0;
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    transition: color var(--duration-fast);
}
.article-toc-sidebar .toc-children a:hover,
.article-toc-sidebar .toc-children a.active { color: var(--color-accent); }
.article-toc-sidebar a.toc-h2 { font-weight: var(--weight-medium); }
.article-toc-sidebar a.toc-h3 { padding-left: var(--space-4); font-size: var(--text-xs); }

/* Article Header — Editorial left-aligned */
.article-header {
    margin-bottom: var(--space-8);
    position: relative;
    padding-left: var(--space-6);
    border-left: 2px solid var(--color-accent);
}
.article-title {
    font-size: clamp(1.75rem, 4.5vw, var(--text-4xl));
    font-weight: var(--weight-extrabold);
    letter-spacing: -0.04em;
    line-height: 1.12;
    margin-bottom: var(--space-4);
    color: var(--color-text);
    text-wrap: balance;
}
.article-meta {
    display: flex;
    align-items: center;
    gap: var(--space-5);
    flex-wrap: wrap;
    font-size: var(--text-sm);
    color: var(--color-text-tertiary);
    font-family: var(--font-mono);
}
.meta-item { display: flex; align-items: center; gap: var(--space-2); }
.meta-item svg { width: 15px; height: 15px; opacity: 0.45; }

.article-tags-row {
    display: flex;
    gap: var(--space-2);
    flex-wrap: wrap;
    margin-bottom: var(--space-4);
}

/* Back link — aligned with header left edge */
.article-back-link {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    color: var(--color-text-tertiary);
    padding: var(--space-2) 0;
    margin-bottom: var(--space-6);
    margin-left: var(--space-6);
    transition: color var(--duration-fast);
}
.article-back-link:hover { color: var(--color-accent); }

/* === Article Content — Refined Swiss typography === */
.article-content {
    font-size: var(--text-base);
    line-height: 1.85;
    color: var(--color-text);
    word-break: break-word;
}

/* Lead paragraph — slightly larger, sets tone */
.article-content > p:first-of-type {
    font-size: var(--text-lg);
    line-height: 1.75;
    color: var(--color-text-secondary);
    margin-bottom: var(--space-7);
}

.article-content h2 {
    font-size: var(--text-2xl);
    font-weight: var(--weight-bold);
    letter-spacing: -0.025em;
    line-height: 1.3;
    margin-top: var(--space-9);
    margin-bottom: var(--space-3);
    padding-bottom: var(--space-3);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text);
    scroll-margin-top: calc(var(--nav-height) + var(--space-4));
}
.article-content h2:first-child { margin-top: 0; }

.article-content h3 {
    font-size: var(--text-xl);
    font-weight: var(--weight-semibold);
    letter-spacing: -0.02em;
    line-height: 1.35;
    margin-top: var(--space-7);
    margin-bottom: var(--space-3);
    color: var(--color-text);
    scroll-margin-top: calc(var(--nav-height) + var(--space-4));
}

.article-content h4 {
    font-size: var(--text-base);
    font-weight: var(--weight-semibold);
    margin-top: var(--space-6);
    margin-bottom: var(--space-2);
    color: var(--color-text-secondary);
}

.article-content p {
    margin-bottom: var(--space-4);
}
.article-content p:empty { display: none; }

.article-content a {
    color: var(--color-accent);
    text-decoration: underline;
    text-decoration-color: var(--color-accent-muted);
    text-underline-offset: 3px;
    text-decoration-thickness: 1px;
    transition: text-decoration-color var(--duration-fast);
}
.article-content a:hover { text-decoration-color: var(--color-accent); }

.article-content strong {
    color: var(--color-text);
    font-weight: var(--weight-semibold);
}

/* Lists — clean geometric markers */
.article-content ul,
.article-content ol {
    margin-bottom: var(--space-5);
    padding-left: 0;
}
.article-content ul { list-style: none; }
.article-content ul li {
    position: relative;
    padding-left: var(--space-6);
    margin-bottom: var(--space-2);
    line-height: 1.7;
}
.article-content ul li::before {
    content: '';
    position: absolute;
    left: var(--space-2);
    top: 0.75em;
    width: 5px;
    height: 5px;
    background: var(--color-accent);
    border-radius: 50%;
    opacity: 0.6;
}
.article-content ol {
    counter-reset: item;
    list-style: none;
}
.article-content ol li {
    counter-increment: item;
    position: relative;
    padding-left: var(--space-7);
    margin-bottom: var(--space-2);
    line-height: 1.7;
}
.article-content ol li::before {
    content: counter(item);
    position: absolute;
    left: 0;
    top: 0;
    width: 22px;
    height: 22px;
    background: var(--color-primary-soft);
    color: var(--color-text-secondary);
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    font-family: var(--font-mono);
    border-radius: var(--radius-xs);
    display: flex;
    align-items: center;
    justify-content: center;
    line-height: 1;
}

/* Nested lists */
.article-content li > ul,
.article-content li > ol {
    margin-top: var(--space-2);
    margin-bottom: 0;
}

/* Blockquotes — distinctive editorial pull */
.article-content blockquote {
    border-left: 3px solid var(--color-accent);
    background: var(--color-accent-soft);
    padding: var(--space-4) var(--space-5);
    margin: var(--space-7) 0;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    color: var(--color-text-secondary);
    font-size: var(--text-base);
    line-height: 1.75;
}
.article-content blockquote p { margin-bottom: 0; }
.article-content blockquote strong { color: var(--color-text); }

/* Callout boxes */
.callout {
    padding: var(--space-4) var(--space-5);
    border-radius: var(--radius-md);
    margin: var(--space-7) 0;
    border: 1px solid;
    font-size: var(--text-sm);
    line-height: var(--leading-relaxed);
}
.callout-info { background: var(--color-primary-soft); border-color: var(--color-primary-muted); color: var(--color-text); }
.callout-warning { background: var(--color-warning-soft); border-color: #FED7AA; color: #9A3412; }
.callout-tip { background: var(--color-success-soft); border-color: #BBF7D0; color: #166534; }
.dark .callout-warning { color: #FDBA74; }
.dark .callout-tip { color: #86EFAC; }

/* Inline code */
.article-content code {
    background: var(--color-code-inline-bg);
    color: var(--color-code-inline-text);
    padding: 2px 6px;
    border-radius: var(--radius-xs);
    font-family: var(--font-mono);
    font-size: 0.875em;
    font-weight: var(--weight-medium);
    white-space: nowrap;
}

/* Code blocks — dark surface, integrated */
.article-content pre {
    background: var(--color-code-bg);
    color: var(--color-code-text);
    padding: var(--space-5) var(--space-6);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: var(--space-7) 0;
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    line-height: 1.75;
    border: 1px solid var(--color-code-border);
    position: relative;
}
.article-content pre code {
    background: none;
    color: inherit;
    padding: 0;
    font-size: inherit;
    font-weight: inherit;
    white-space: pre;
}

/* Tables — clean, geometric */
.article-content table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
    margin: var(--space-7) 0;
    font-size: var(--text-sm);
    border-radius: var(--radius-md);
    overflow: hidden;
    border: 1px solid var(--color-border);
}
.article-content thead { background: var(--color-bg-raised); }
.article-content th {
    padding: var(--space-3) var(--space-4);
    text-align: left;
    font-weight: var(--weight-semibold);
    color: var(--color-text);
    border-bottom: 2px solid var(--color-border);
    font-size: var(--text-xs);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.article-content td {
    padding: var(--space-3) var(--space-4);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    line-height: 1.6;
}
.article-content tr:last-child td { border-bottom: none; }
.article-content tbody tr { transition: background var(--duration-fast); }
.article-content tbody tr:hover td { background: var(--color-surface-hover); }

/* Images — centered, breathing room */
.article-content img {
    display: block;
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-md);
    margin: var(--space-8) auto;
    border: 1px solid var(--color-border);
}

/* Horizontal rules — subtle separator */
.article-content hr {
    border: none;
    height: 1px;
    background: var(--color-border);
    margin: var(--space-10) 0;
}

/* Description lists */
.article-content dt {
    font-weight: var(--weight-semibold);
    color: var(--color-text);
    margin-top: var(--space-4);
}
.article-content dd {
    margin-left: var(--space-5);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-3);
}

/* Keyboard / kbd */
.article-content kbd {
    display: inline-block;
    padding: 1px 6px;
    font-family: var(--font-mono);
    font-size: 0.8em;
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    background: var(--color-bg-raised);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    box-shadow: 0 1px 0 var(--color-border);
    line-height: 1.5;
}

/* === Article Footer === */
.article-footer {
    margin-top: var(--space-10);
    padding-top: var(--space-7);
    border-top: 1px solid var(--color-border);
}
.article-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-5);
    margin-bottom: var(--space-8);
}
.article-nav-card {
    display: flex;
    flex-direction: column;
    padding: var(--space-5);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: all var(--duration-base) var(--ease-out);
}
.article-nav-card:hover {
    border-color: var(--color-border-hover);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}
.article-nav-card.next { text-align: right; align-items: flex-end; }
.article-nav-label {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    font-weight: var(--weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: var(--space-2);
}
.article-nav-title {
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    color: var(--color-text);
    line-height: var(--leading-snug);
}
.article-nav-card:hover .article-nav-title { color: var(--color-accent); }

.related-section h3 {
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    margin-bottom: var(--space-5);
    color: var(--color-text);
}
.related-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: var(--space-3);
}
.related-card {
    display: block;
    padding: var(--space-4);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    transition: all var(--duration-fast);
}
.related-card:hover {
    border-color: var(--color-accent-muted);
    color: var(--color-accent);
    background: var(--color-accent-soft);
}

/* TOC Link */
.toc-link {
    display: block;
    padding: var(--space-1) 0;
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    text-decoration: none;
    transition: color var(--duration-fast);
    border-radius: var(--radius-xs);
}
.toc-link:hover { color: var(--color-accent); }
.toc-link.active { color: var(--color-accent); font-weight: var(--weight-medium); }

/* Mobile TOC */
.article-toc-mobile {
    display: block;
    margin-bottom: var(--space-6);
}
@media (min-width: 1024px) {
    .article-toc-mobile { display: none; }
}
.article-toc-mobile > summary {
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    color: var(--color-text-secondary);
    cursor: pointer;
    padding: var(--space-3) var(--space-4);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    list-style: none;
}
.article-toc-mobile > summary::-webkit-details-marker { display: none; }
.article-toc-mobile .toc-list {
    padding: var(--space-3) var(--space-4);
    background: var(--color-surface-alt);
    border: 1px solid var(--color-border);
    border-top: none;
    border-radius: 0 0 var(--radius-md) var(--radius-md);
}
.article-toc-mobile .toc-group { margin-bottom: var(--space-2); }
.article-toc-mobile .toc-group > .toc-link {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    color: var(--color-text);
    font-weight: var(--weight-medium);
    padding: var(--space-1) 0;
}
.article-toc-mobile .toc-group > .toc-link::before {
    content: '▸';
    font-size: 10px;
    color: var(--color-text-tertiary);
    transition: transform var(--duration-fast);
}
.article-toc-mobile .toc-group.open > .toc-link::before { transform: rotate(90deg); }
.article-toc-mobile .toc-children {
    display: none;
    padding-left: var(--space-4);
    margin-top: var(--space-1);
}
.article-toc-mobile .toc-group.open > .toc-children { display: block; }
.article-toc-mobile .toc-children a {
    display: block;
    padding: var(--space-1) 0;
    font-size: var(--text-xs);
    color: var(--color-text-secondary);
}

/* ========================================
   About Page — Editorial profile
   ======================================== */
.about-page { max-width: var(--wide-width); margin: 0 auto; width: 100%; box-sizing: border-box; }
.about-content {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-6);
}
.about-content p { color: var(--color-text-secondary); margin-bottom: var(--space-3); line-height: var(--leading-relaxed); }
.about-content p:last-child { margin-bottom: 0; }
.about-hero {
    text-align: center;
    padding: var(--space-10) 0 var(--space-8);
    position: relative;
}
/* Subtle ring behind avatar */
.about-hero::before {
    content: '';
    position: absolute;
    top: calc(var(--space-10) + 48px);
    left: 50%;
    transform: translate(-50%, -50%);
    width: 140px; height: 140px;
    border-radius: 50%;
    border: 1px solid var(--color-border);
    opacity: 0.5;
}
.about-avatar {
    width: 96px; height: 96px;
    margin: 0 auto var(--space-5);
    border-radius: 50%;
    background: var(--color-bg-raised);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text);
    transition: all var(--duration-base) var(--ease-out);
    border: 2px solid var(--color-border);
    position: relative;
    z-index: 1;
}
.about-avatar:hover {
    transform: scale(1.04);
    border-color: var(--color-accent);
    box-shadow: 0 0 0 8px var(--color-accent-soft);
}
.about-name {
    font-size: var(--text-3xl);
    font-weight: var(--weight-extrabold);
    letter-spacing: -0.035em;
    margin-bottom: var(--space-2);
    color: var(--color-text);
    position: relative;
    z-index: 1;
}
.about-tagline {
    font-size: var(--text-lg);
    color: var(--color-text-secondary);
    position: relative;
    z-index: 1;
}

/* About sections — varied, not all cards */
.about-section {
    margin-bottom: var(--space-7);
}
.about-section h2 {
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    margin-bottom: var(--space-5);
    color: var(--color-text);
    display: flex;
    align-items: center;
    gap: var(--space-3);
}
.about-section h2::after {
    content: '';
    flex: 0 0 32px;
    height: 1px;
    background: var(--color-accent-muted);
}
.about-content p {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-3);
    line-height: var(--leading-relaxed);
}
.about-content ul {
    list-style: none;
    padding: 0;
    margin-bottom: var(--space-4);
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
}
.about-content ul li {
    padding: var(--space-1) var(--space-3);
    background: var(--color-bg-raised);
    border-radius: var(--radius-xs);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
}

/* About Horizontal (Home page) */
.about-horizontal {
    display: flex;
    align-items: center;
    gap: var(--space-5);
    flex-wrap: wrap;
    padding: var(--space-6);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    transition: all var(--duration-base);
}
.about-horizontal:hover { border-color: var(--color-border-hover); box-shadow: var(--shadow-md); }
.about-horizontal-avatar {
    width: 72px; height: 72px;
    flex-shrink: 0;
    border-radius: 50%;
    background: var(--color-bg-raised);
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--color-text);
    border: 2px solid var(--color-border);
}
.about-horizontal-body { flex: 1; min-width: 200px; }
.about-horizontal-name {
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    margin-bottom: var(--space-2);
    color: var(--color-text);
}
.about-horizontal-desc {
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    line-height: var(--leading-relaxed);
    margin-bottom: var(--space-3);
}
.about-horizontal-link {
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    color: var(--color-accent);
    display: inline-flex;
    align-items: center;
    gap: var(--space-1);
    padding: var(--space-2) var(--space-3);
    border-radius: var(--radius-sm);
    transition: all var(--duration-base) var(--ease-out);
}
.about-horizontal-link:hover { gap: var(--space-3); background: var(--color-accent-soft); }

.skills-grid { display: grid; gap: var(--space-5); }
.skill-category h3 { font-size: var(--text-sm); font-weight: var(--weight-semibold); color: var(--color-text); margin-bottom: var(--space-3); }
.skill-tags { display: flex; flex-wrap: wrap; gap: var(--space-2); }
.skill-tag {
    padding: var(--space-1) var(--space-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    font-size: var(--text-xs);
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    background: var(--color-surface);
    transition: all var(--duration-fast);
}
.skill-tag:hover { border-color: var(--color-accent); color: var(--color-accent); background: var(--color-accent-soft); }

/* Contact */
.contact-list { display: flex; flex-direction: column; gap: var(--space-3); }
.contact-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    font-size: var(--text-sm);
    transition: background var(--duration-fast);
}
.contact-item:hover { background: var(--color-bg-raised); }
.contact-item svg { color: var(--color-accent); flex-shrink: 0; opacity: 0.65; }

/* Stats */
.stats-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-4); }
.stat-card {
    text-align: center;
    padding: var(--space-6);
    background: var(--color-bg-raised);
    border-radius: var(--radius-lg);
    border: 1px solid transparent;
    transition: all var(--duration-base) var(--ease-out);
}
.stat-card:hover { border-color: var(--color-border); box-shadow: var(--shadow-md); transform: translateY(-2px); }
.stat-number {
    display: block;
    font-size: var(--text-4xl);
    font-weight: var(--weight-extrabold);
    letter-spacing: -0.04em;
    color: var(--color-accent);
    margin-bottom: var(--space-1);
}
.stat-label {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    font-weight: var(--weight-medium);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

/* ========================================
   Search Page — Clean, focused
   ======================================== */
.search-page-section { margin-bottom: var(--space-6); }
.search-input-group { display: flex; gap: var(--space-3); max-width: 600px; margin: 0 auto; }
.search-input-group input {
    flex: 1;
    padding: 12px var(--space-5);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--text-base);
    color: var(--color-text);
    background: var(--color-surface);
    outline: none;
    transition: all var(--duration-base);
}
.search-input-group input:focus {
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 4px rgb(0 0 0 / 0.04);
}
.hot-search { text-align: center; margin-top: var(--space-8); }
.hot-search-label {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.1em;
    font-weight: var(--weight-semibold);
    margin-bottom: var(--space-5);
    position: relative;
    display: inline-block;
}
.hot-search-label::after {
    content: '';
    display: block;
    width: 20px; height: 1px;
    margin: var(--space-2) auto 0;
    background: var(--color-accent);
}
.hot-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    gap: var(--space-3);
    max-width: 640px;
    margin: 0 auto;
}
.hot-tag {
    padding: 8px 18px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    font-weight: var(--weight-medium);
    background: var(--color-surface);
    cursor: pointer;
    transition: all var(--duration-base) var(--ease-out);
    text-decoration: none;
    position: relative;
}
.hot-tag:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    background: var(--color-accent-soft);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgb(236 72 153 / 0.12);
}
/* Popularity sizing — subtle scale variation */
.hot-tag-size-1 { font-size: var(--text-xs); padding: 6px 12px; }
.hot-tag-size-2 { font-size: var(--text-sm); padding: 7px 15px; }
.hot-tag-size-3 { font-size: var(--text-base); padding: 9px 20px; font-weight: var(--weight-semibold); }
.hot-tag-with-count { display: inline-flex; align-items: center; gap: var(--space-2); }
.hot-tag-count {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 20px; height: 20px;
    padding: 0 5px;
    background: var(--color-bg-raised);
    border-radius: var(--radius-full);
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    color: var(--color-text-tertiary);
    font-family: var(--font-mono);
}
.results-header {
    margin-bottom: var(--space-5);
    padding: var(--space-3) 0;
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}
.results-header strong { color: var(--color-text); }

/* ========================================
   Short URL Page — Clean tool layout
   ======================================== */
.status-bar {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: 0;
    flex-wrap: wrap;
}
.status-indicator {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3) var(--space-5);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    border: 1px solid transparent;
}
.status-dot {
    width: 8px; height: 8px;
    border-radius: 50%;
    flex-shrink: 0;
    position: relative;
}
.status-dot::after {
    content: '';
    position: absolute;
    inset: -3px;
    border-radius: 50%;
    opacity: 0.25;
}
.status-ok {
    background: var(--color-success-soft);
    border-color: #BBF7D0;
    color: #166534;
}
.status-ok .status-dot { background: var(--color-success); }
.status-ok .status-dot::after { background: var(--color-success); }
.status-warn {
    background: var(--color-warning-soft);
    border-color: #FED7AA;
    color: #9A3412;
}
.status-warn .status-dot { background: var(--color-warning); }
.status-warn .status-dot::after { background: var(--color-warning); }
.status-error {
    background: var(--color-error-soft);
    border-color: #FECACA;
    color: #991B1B;
}
.status-error .status-dot { background: var(--color-error); }
.status-error .status-dot::after { background: var(--color-error); }
.status-time {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    margin-left: auto;
    font-family: var(--font-mono);
}

.short-url-container { max-width: 960px; width: 100%; margin: 0 auto; padding: 0 var(--space-6); box-sizing: border-box; }
.short-url-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-4);
    margin-top: var(--space-6);
}
.short-url-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--space-5) var(--space-4);
}
.short-url-card h2 {
    font-size: var(--text-lg);
    font-weight: var(--weight-bold);
    margin-bottom: var(--space-5);
    padding-bottom: var(--space-3);
    border-bottom: 1px solid var(--color-border);
    color: var(--color-text);
}
.form-group { margin-bottom: var(--space-4); }
.form-group label {
    display: block;
    font-size: var(--text-xs);
    font-weight: var(--weight-semibold);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-2);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}
.form-group input {
    width: 100%;
    padding: 10px var(--space-3);
    border: 2px solid var(--color-border);
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    color: var(--color-text);
    background: var(--color-surface);
    outline: none;
    transition: all var(--duration-base);
}
.form-group input:focus {
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 4px rgb(0 0 0 / 0.04);
}
.result-box {
    margin-top: var(--space-5);
    padding: var(--space-4);
    background: var(--color-bg-raised);
    border-radius: var(--radius-md);
    border: 1px solid var(--color-border);
}
.result-row { margin-bottom: var(--space-3); }
.result-row:last-child { margin-bottom: 0; }
.result-label {
    display: block;
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    margin-bottom: var(--space-1);
    font-weight: var(--weight-medium);
}
.copy-row { display: flex; gap: var(--space-2); }
.copy-row input {
    flex: 1;
    padding: 7px 10px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-size: var(--text-sm);
    font-family: var(--font-mono);
    background: var(--color-surface);
    color: var(--color-text);
}

.stat-hero {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--space-6);
    background: var(--color-surface);
    border-radius: var(--radius-md);
    color: var(--color-text);
    text-align: center;
}
.stat-hero-number {
    font-size: var(--text-4xl);
    font-weight: var(--weight-extrabold);
    letter-spacing: -0.04em;
}
.stat-hero-label { font-size: var(--text-sm); opacity: 0.8; margin-top: var(--space-1); }
.stat-details { margin-top: var(--space-3); }
.stat-item {
    display: flex; gap: var(--space-3);
    padding: var(--space-2) 0;
    border-bottom: 1px solid var(--color-border);
    font-size: var(--text-sm);
}
.stat-item:last-child { border-bottom: none; }
.stat-item-label {
    flex-shrink: 0; width: 72px;
    font-weight: var(--weight-semibold);
    color: var(--color-text-secondary);
    font-size: var(--text-xs);
    text-transform: uppercase;
    letter-spacing: 0.03em;
}
.stat-item-value { color: var(--color-text); word-break: break-all; }

.stat-code {
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    background: var(--color-bg-raised);
    color: var(--color-text);
    padding: 2px 8px;
    border-radius: var(--radius-sm);
    word-break: break-all;
}
.stat-long-url {
    font-size: var(--text-xs);
    color: var(--color-accent);
    word-break: break-all;
    display: block;
    font-weight: var(--weight-medium);
    text-decoration: none;
}
.stat-long-url:hover { color: var(--color-accent-hover); }

.btn-copy-mini {
    flex-shrink: 0;
    width: 28px; height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-surface);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--duration-fast);
}
.btn-copy-mini:hover { border-color: var(--color-accent); color: var(--color-accent); background: var(--color-accent-soft); }

.error-msg {
    margin-top: var(--space-4);
    padding: var(--space-3) var(--space-4);
    background: var(--color-error-soft);
    border: 1px solid #FECACA;
    border-radius: var(--radius-md);
    color: var(--color-error);
    font-size: var(--text-sm);
}
.dark .error-msg { color: #FCA5A5; }

/* ========================================
   Buttons — Swiss precision
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: 10px 20px;
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: var(--weight-semibold);
    letter-spacing: 0.01em;
    transition: all var(--duration-fast);
    white-space: nowrap;
}
.btn:active { transform: scale(0.97); }
.btn-primary {
    background: linear-gradient(135deg, #FF6600 0%, #E55A00 100%);
    color: #FFFFFF;
    border: 1px solid transparent;
}
.btn-primary:hover { opacity: 0.9; transform: translateY(-1px); }
.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text-secondary);
    border: 1px solid var(--color-border);
}
.btn-secondary:hover { border-color: var(--color-border-hover); background: var(--color-bg-raised); color: var(--color-text); }
.btn-ghost { background: transparent; color: var(--color-text-secondary); }
.btn-ghost:hover { background: var(--color-bg-raised); color: var(--color-text); }
.btn-full { width: 100%; }
.btn-sm { padding: 6px 12px; font-size: var(--text-xs); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ========================================
   Toast
   ======================================== */
.toast {
    position: fixed;
    bottom: var(--space-6);
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--color-text);
    color: var(--color-bg);
    padding: 10px 22px;
    border-radius: var(--radius-md);
    font-size: var(--text-sm);
    font-weight: var(--weight-medium);
    opacity: 0;
    transition: all var(--duration-base) var(--ease-out);
    z-index: 1000;
    pointer-events: none;
    box-shadow: var(--shadow-xl);
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ========================================
   Back to Top
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    width: 40px; height: 40px;
    border-radius: var(--radius-full);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    color: var(--color-text-secondary);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0; visibility: hidden;
    transform: translateY(8px);
    transition: all var(--duration-base) var(--ease-out);
    z-index: 90;
    box-shadow: var(--shadow-md);
}
.back-to-top.visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

/* ========================================
   Guide Modal — Clean overlay
   ======================================== */
.guide-overlay {
    position: fixed; inset: 0;
    background: rgb(0 0 0 / 0.3);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    display: none;
    align-items: center; justify-content: center;
    z-index: 1000;
    padding: var(--space-5);
}
.guide-modal {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: var(--space-7);
    max-width: 420px;
    text-align: center;
    box-shadow: var(--shadow-xl);
    animation: modal-in var(--duration-slow) var(--ease-out);
}
@keyframes modal-in {
    from { opacity: 0; transform: translateY(16px) scale(0.96); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}
.guide-modal h3 {
    font-size: var(--text-xl);
    font-weight: var(--weight-bold);
    margin-bottom: var(--space-3);
    color: var(--color-text);
}
.guide-modal p {
    color: var(--color-text-secondary);
    margin-bottom: var(--space-4);
    font-size: var(--text-sm);
    line-height: var(--leading-relaxed);
}
.guide-modal ul { text-align: left; list-style: none; padding: 0; margin-bottom: var(--space-5); }
.guide-modal ul li { padding: var(--space-2) 0; font-size: var(--text-sm); color: var(--color-text-secondary); display: flex; align-items: center; gap: var(--space-2); }
.guide-modal ul li svg { flex-shrink: 0; color: var(--color-accent); }
.guide-modal .btn { width: 100%; }

/* ========================================
   Empty State
   ======================================== */
.empty-state { text-align: center; padding: var(--space-10) var(--space-5); }
.empty-state-icon {
    width: 56px; height: 56px;
    margin: 0 auto var(--space-5);
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: var(--color-bg-raised);
    color: var(--color-text-tertiary);
}
.empty-state p { color: var(--color-text-tertiary); font-size: var(--text-base); }

.empty-state-creative {
    text-align: center;
    padding: var(--space-10) var(--space-5);
}
.empty-state-illustration {
    margin: 0 auto var(--space-5);
    opacity: 0.5;
}
.empty-state-title {
    font-size: var(--text-xl);
    font-weight: var(--weight-semibold);
    color: var(--color-text);
    margin-bottom: var(--space-2);
}
.empty-state-hint {
    font-size: var(--text-sm);
    color: var(--color-text-tertiary);
    margin-bottom: var(--space-5);
}
.empty-state-suggestions {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-2);
    justify-content: center;
    align-items: center;
    font-size: var(--text-sm);
    color: var(--color-text-tertiary);
}
.empty-state-suggestions a {
    padding: var(--space-1) var(--space-3);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xs);
    font-size: var(--text-xs);
    font-weight: var(--weight-medium);
    color: var(--color-text-secondary);
    transition: all var(--duration-fast);
    text-decoration: none;
}
.empty-state-suggestions a:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
    background: var(--color-accent-soft);
}

/* ========================================
   Footer — Clean, minimal
   ======================================== */
.footer {
    border-top: 1px solid var(--color-border);
    padding: var(--space-7) 0;
    text-align: center;
}
.footer-inner {
    max-width: var(--content-width);
    margin: 0 auto;
    padding: 0 var(--space-6);
}

.footer-nav {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: var(--space-1);
    margin-bottom: var(--space-5);
    flex-wrap: wrap;
}
.footer-nav a {
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-sm);
    color: var(--color-text-tertiary);
    border-radius: var(--radius-sm);
    transition: color var(--duration-fast), background var(--duration-fast);
}
.footer-nav a:hover {
    color: var(--color-accent);
    background: var(--color-accent-soft);
}

.footer-copyright {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    margin: 0;
}
.footer-beian {
    font-size: var(--text-xs);
    color: var(--color-text-tertiary);
    margin: var(--space-2) 0 0;
}
.footer-beian a {
    color: inherit;
    text-decoration: none;
    transition: color var(--duration-fast);
}
.footer-beian a:hover {
    color: var(--color-accent);
}

/* ========================================
   Scroll Reveal Animations
   ======================================== */
.js .reveal {
    opacity: 0;
    transform: translateY(20px);
    transition-property: opacity, transform;
    transition-duration: var(--duration-glacial);
    transition-timing-function: var(--ease-out);
}
.reveal.revealed {
    opacity: 1;
    transform: translateY(0);
}
.js .reveal-left {
    opacity: 0;
    transform: translateX(-16px);
    transition-property: opacity, transform;
    transition-duration: var(--duration-glacial);
    transition-timing-function: var(--ease-out);
}
.reveal-left.revealed {
    opacity: 1;
    transform: translateX(0);
}

.js .reveal-stagger > * {
    opacity: 0;
    transform: translateY(16px);
    transition-property: opacity, transform;
    transition-duration: var(--duration-slow);
    transition-timing-function: var(--ease-out);
}
.reveal-stagger > *.revealed {
    opacity: 1;
    transform: translateY(0);
}

/* Reveal Delay Variants */
.reveal-delay-1 { transition-delay: 80ms; }
.reveal-delay-2 { transition-delay: 160ms; }
.reveal-delay-3 { transition-delay: 240ms; }

/* ========================================
   Skeleton Loading
   ======================================== */
.skeleton {
    background: linear-gradient(90deg, var(--color-bg-raised) 25%, var(--color-border) 50%, var(--color-bg-raised) 75%);
    background-size: 200% 100%;
    animation: skeleton-shimmer 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}
@keyframes skeleton-shimmer {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}
.skeleton-card { height: 160px; border-radius: var(--radius-md); margin-bottom: var(--space-4); }

/* ========================================
   Utilities
   ======================================== */
.hidden { display: none !important; }

/* ========================================
   Reduced Motion
   ======================================== */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
    html { scroll-behavior: auto; }
    .reveal, .reveal-left, .reveal-stagger > * {
        opacity: 1 !important;
        transform: none !important;
    }
}

/* ========================================
   Responsive — Tablet (768px - 1023px)
   ======================================== */
@media (min-width: 1024px) {
    .article-toc-sidebar { display: block; }
}

@media (max-width: 1023px) {
    .articles-grid { grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); }
    .article-detail-wrapper { flex-direction: column; }
    .article-toc-sidebar { display: none; }
    .article-list-card { padding: var(--space-4); }
    .article-nav { grid-template-columns: 1fr; }
    .short-url-grid { grid-template-columns: 1fr; }
    .article-content { font-size: var(--text-base); }
}

/* ========================================
   Responsive — Mobile (< 768px)
   ======================================== */
@media (max-width: 767px) {
    :root { --nav-height: 52px; }
    .container, .container-narrow, .navbar-inner { padding-left: var(--space-4); padding-right: var(--space-4); }

    .nav-links {
        display: none;
        position: absolute;
        top: var(--nav-height); left: 0; right: 0;
        background: var(--color-surface);
        border-bottom: 1px solid var(--color-border);
        flex-direction: column;
        padding: var(--space-2);
        gap: 0;
        box-shadow: var(--shadow-xl);
        z-index: 99;
    }
    .nav-links.active { display: flex; }
    .nav-links a { padding: 10px var(--space-4); border-radius: var(--radius-sm); }
    .mobile-menu-btn { display: flex; }

    .hero { padding: var(--space-8) 0 var(--space-6); }
    .hero-title { font-size: 1.8rem; }
    .hero-subtitle { font-size: var(--text-base); margin-bottom: var(--space-6); }

    .search-box { flex-direction: column; }
    .search-box input { padding: var(--space-3) var(--space-4); }
    .search-box-btn { width: 100%; border-radius: var(--radius-sm); padding: var(--space-3); }
    .search-box-shortcut { display: none; }

    .articles-grid { grid-template-columns: 1fr; gap: var(--space-4); }
    .articles-grid .article-card:first-child {
        padding-left: var(--space-5);
    }
    .articles-grid .article-card:first-child .article-card-title { font-size: var(--text-xl); }
    .article-card { padding: var(--space-5); }

    /* Categories — compact pill row on mobile */
    .categories-grid { gap: var(--space-2); }
    .category-card { padding: var(--space-2) var(--space-3); font-size: var(--text-xs); }
    .category-icon-box { width: 32px; height: 32px; }
    .category-icon-box svg { width: 16px; height: 16px; }
    .category-count { display: none; }

    .page-title { font-size: 1.75rem; }
    .page-header { padding: var(--space-6) 0 var(--space-5); }
    .article-title { font-size: 1.5rem; }
    .article-header {
        margin-bottom: var(--space-6);
        padding-left: var(--space-4);
    }
    .article-back-link { margin-left: var(--space-4); }
    .article-content { font-size: 0.9375rem; }
    .article-content > p:first-of-type { font-size: var(--text-base); }
    .article-content h2 { font-size: var(--text-xl); }
    .article-content h3 { font-size: var(--text-lg); }
    .article-content pre { padding: var(--space-4); border-radius: var(--radius-sm); font-size: var(--text-xs); }
    .article-content blockquote { padding: var(--space-3) var(--space-4); }
    .article-content ol li::before { width: 20px; height: 20px; font-size: 0.625rem; }
    .article-content img { margin: var(--space-6) auto; }

    .filter-bar { flex-direction: column; align-items: stretch; }
    .filter-tabs { overflow-x: auto; flex-wrap: nowrap; padding: var(--space-1); }
    .filter-tab { white-space: nowrap; font-size: var(--text-xs); }
    .filter-sort select { width: 100%; }

    .hot-tags { gap: var(--space-2); }
    .hot-tag { padding: 6px 14px; }
    .hot-tag-size-3 { font-size: var(--text-sm); padding: 7px 16px; }

    .stats-grid { gap: var(--space-2); }
    .stat-card { padding: var(--space-4); }
    .stat-number { font-size: var(--text-2xl); }
    .short-url-card { padding: var(--space-4); }
    .status-bar { gap: var(--space-2); }
    .status-indicator { padding: var(--space-2) var(--space-3); font-size: var(--text-xs); }
    .status-time { margin-left: 0; width: 100%; text-align: center; }

    /* About page mobile */
    .about-hero { padding: var(--space-6) 0 var(--space-5); }
    .about-hero::before { width: 100px; height: 100px; top: calc(var(--space-6) + 32px); }
    .about-avatar { width: 72px; height: 72px; }
    .about-name { font-size: var(--text-2xl); }
    .about-section h2 { font-size: var(--text-base); }
    .about-horizontal { flex-direction: column; text-align: center; padding: var(--space-5); }
    .about-horizontal-body { text-align: center; }
    .skills-grid { grid-template-columns: 1fr; gap: var(--space-4); }
    .contact-item { font-size: var(--text-xs); }

    /* Article meta compact */
    .article-meta { gap: var(--space-3); font-size: var(--text-xs); }
    .article-tags-row { gap: var(--space-1); }

    /* Hero accent line shorter on mobile */
    .hero::before { height: 48px; }

    .footer { padding: var(--space-5) 0; }
    .guide-modal { padding: var(--space-5); margin: var(--space-4); border-radius: var(--radius-md); }
    .back-to-top { bottom: var(--space-4); right: var(--space-4); }
}