/* ============================================
   Blog v2.0 — Design System
   Apple-inspired × Chinese Red × Glassmorphism
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
    /* Backgrounds */
    --bg-primary: #F5F5F7;
    --bg-secondary: #EEEEF0;
    --card-bg: #FFFFFF;
    --nav-bg: rgba(255, 255, 255, 0.72);
    --overlay-bg: rgba(0, 0, 0, 0.4);

    /* Text */
    --text-primary: #1D1D1F;
    --text-secondary: #6E6E73;
    --text-tertiary: #86868B;
    --text-inverse: #FFFFFF;

    /* Theme — Chinese Red */
    --red: #E60012;
    --red-hover: #CC0010;
    --red-light: rgba(230, 0, 18, 0.08);
    --red-glow: rgba(230, 0, 18, 0.15);
    --gold: #D4A853;

    /* Borders */
    --border: rgba(0, 0, 0, 0.06);
    --border-strong: rgba(0, 0, 0, 0.12);

    /* Shadows */
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.04);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.04), 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08), 0 2px 4px rgba(0, 0, 0, 0.04);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.12), 0 4px 12px rgba(0, 0, 0, 0.06);
    --shadow-glow: 0 0 24px var(--red-glow);

    /* Radius */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-full: 9999px;

    /* Spacing */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 16px;
    --space-lg: 24px;
    --space-xl: 32px;
    --space-2xl: 48px;
    --space-3xl: 64px;

    /* Timing */
    --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --duration-fast: 0.2s;
    --duration-normal: 0.3s;
    --duration-slow: 0.5s;

    /* Layout */
    --max-width: 900px;
    --max-width-detail: 760px;
    --nav-height: 56px;
}

/* ---------- Dark Mode ---------- */
[data-theme="dark"] {
    --bg-primary: #1C1C1E;
    --bg-secondary: #2C2C2E;
    --card-bg: #2C2C2E;
    --nav-bg: rgba(28, 28, 30, 0.78);
    --overlay-bg: rgba(0, 0, 0, 0.6);
    --text-primary: #F5F5F7;
    --text-secondary: #A1A1A6;
    --text-tertiary: #8E8E93;
    --red-light: rgba(230, 0, 18, 0.18);
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.15);
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.2);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.5);
}

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

html {
    scroll-behavior: smooth;
    scroll-padding-top: calc(var(--nav-height) + 24px);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Helvetica Neue", Roboto, Arial, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background var(--duration-normal) ease, color var(--duration-normal) ease;
    overflow-x: hidden;
    padding-top: var(--nav-height);
}

body.menu-open {
    overflow: hidden;
}

a {
    color: inherit;
    text-decoration: none;
}

img {
    max-width: 100%;
}

/* ---------- Reading Progress Bar ---------- */
.progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 3px;
    background: linear-gradient(90deg, var(--red), #FF4D4D);
    z-index: 1001;
    transition: width 0.1s linear;
    border-radius: 0 2px 2px 0;
}

/* ---------- Navigation ---------- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--nav-height);
    background: var(--nav-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    z-index: 1000;
    transition: box-shadow var(--duration-normal) ease, background var(--duration-normal) ease;
}

.navbar.scrolled {
    box-shadow: var(--shadow-sm);
}

.navbar-inner {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-lg);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    font-size: 18px;
    font-weight: 700;
    letter-spacing: -0.01em;
    color: var(--text-primary);
    transition: color var(--duration-fast) ease;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
}

.nav-brand:hover {
    color: var(--red);
}

.nav-brand-icon {
    font-size: 22px;
}

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

.nav-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--duration-fast) ease;
    font-size: 18px;
}

.nav-btn:hover {
    background: var(--red-light);
    color: var(--red);
}

.nav-btn.active {
    background: var(--red-light);
    color: var(--red);
}

/* Mobile menu button */
.menu-toggle {
    display: none;
}

/* ---------- Mobile Sidebar ---------- */
.mobile-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: var(--overlay-bg);
    z-index: 999;
    opacity: 0;
    transition: opacity var(--duration-normal) ease;
}

.mobile-overlay.show {
    display: block;
    opacity: 1;
}

.mobile-sidebar {
    position: fixed;
    top: 0;
    right: -280px;
    width: 280px;
    height: 100%;
    background: var(--card-bg);
    z-index: 1002;
    padding: var(--space-2xl) var(--space-lg);
    transition: right var(--duration-normal) var(--ease-out);
    overflow-y: auto;
}

.mobile-sidebar.show {
    right: 0;
}

.mobile-sidebar-close {
    position: absolute;
    top: var(--space-md);
    right: var(--space-md);
    width: 32px;
    height: 32px;
    border: none;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
}

.mobile-sidebar-close:hover {
    background: var(--red-light);
    color: var(--red);
}

.mobile-nav-section {
    margin-bottom: var(--space-xl);
}

.mobile-nav-title {
    font-size: 13px;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--space-md);
}

.mobile-theme-btn {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    width: 100%;
    padding: var(--space-md);
    border: none;
    background: var(--bg-secondary);
    color: var(--text-primary);
    cursor: pointer;
    border-radius: var(--radius-md);
    font-size: 15px;
    font-family: inherit;
    transition: all var(--duration-fast) ease;
}

.mobile-theme-btn:hover {
    background: var(--red-light);
    color: var(--red);
}

/* ---------- Search Modal ---------- */
.search-modal {
    display: none;
    position: fixed;
    inset: 0;
    z-index: 2000;
    background: var(--overlay-bg);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    padding: 80px var(--space-lg) var(--space-lg);
    opacity: 0;
    transition: opacity var(--duration-normal) ease;
}

.search-modal.show {
    display: flex;
    flex-direction: column;
    align-items: center;
    opacity: 1;
}

.search-container {
    width: 100%;
    max-width: 640px;
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    animation: searchSlideIn var(--duration-normal) var(--ease-out);
}

@keyframes searchSlideIn {
    from {
        opacity: 0;
        transform: translateY(-16px) scale(0.98);
    }

    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.search-input-wrap {
    display: flex;
    align-items: center;
    padding: var(--space-md) var(--space-lg);
    border-bottom: 1px solid var(--border);
    gap: var(--space-md);
}

.search-input-wrap .search-icon {
    color: var(--text-tertiary);
    font-size: 20px;
    flex-shrink: 0;
}

.search-input {
    flex: 1;
    border: none;
    outline: none;
    font-size: 17px;
    font-family: inherit;
    background: transparent;
    color: var(--text-primary);
}

.search-input::placeholder {
    color: var(--text-tertiary);
}

.search-close {
    font-size: 13px;
    padding: 4px 10px;
    border: 1px solid var(--border-strong);
    border-radius: 6px;
    background: var(--bg-secondary);
    color: var(--text-secondary);
    cursor: pointer;
    font-family: inherit;
    flex-shrink: 0;
}

.search-results {
    max-height: 400px;
    overflow-y: auto;
    padding: var(--space-sm);
}

.search-result-item {
    display: block;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    transition: background var(--duration-fast) ease;
    cursor: pointer;
}

.search-result-item:hover {
    background: var(--red-light);
}

.search-result-title {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 4px;
}

.search-result-preview {
    font-size: 13px;
    color: var(--text-secondary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.search-empty {
    padding: var(--space-xl);
    text-align: center;
    color: var(--text-tertiary);
    font-size: 15px;
}

.search-hint {
    padding: var(--space-lg);
    text-align: center;
    color: var(--text-tertiary);
    font-size: 14px;
}

/* ---------- Main Content Wrapper ---------- */
.main-content {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

/* ---------- Hero Section ---------- */
.hero {
    text-align: center;
    padding: var(--space-3xl) 0 var(--space-2xl);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -60%;
    left: 50%;
    transform: translateX(-50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, var(--red-glow) 0%, transparent 70%);
    pointer-events: none;
    opacity: 0.5;
    animation: heroPulse 6s ease-in-out infinite alternate;
}

@keyframes heroPulse {
    from {
        opacity: 0.3;
        transform: translateX(-50%) scale(0.9);
    }

    to {
        opacity: 0.6;
        transform: translateX(-50%) scale(1.1);
    }
}

.hero-title {
    font-size: 48px;
    font-weight: 800;
    letter-spacing: -0.03em;
    line-height: 1.15;
    margin-bottom: var(--space-md);
    position: relative;
    background: linear-gradient(135deg, var(--text-primary) 0%, var(--text-secondary) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

[data-theme="dark"] .hero-title {
    background: linear-gradient(135deg, #FFFFFF 0%, #A1A1A6 100%);
    -webkit-background-clip: text;
    background-clip: text;
}

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    font-weight: 400;
    margin-bottom: var(--space-lg);
    position: relative;
}

.hero-stats {
    display: inline-flex;
    align-items: center;
    gap: var(--space-sm);
    padding: 6px 16px;
    background: var(--red-light);
    color: var(--red);
    font-size: 14px;
    font-weight: 600;
    border-radius: var(--radius-full);
    position: relative;
}

.hero-divider {
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, transparent, var(--red), transparent);
    margin: var(--space-xl) auto 0;
    border-radius: var(--radius-full);
    position: relative;
}

/* ---------- Filter Section ---------- */
.filter-section {
    margin-bottom: var(--space-xl);
}

.filter-tags {
    display: flex;
    gap: var(--space-sm);
    overflow-x: auto;
    padding-bottom: var(--space-sm);
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.filter-tags::-webkit-scrollbar {
    display: none;
}

.filter-tag {
    flex-shrink: 0;
    padding: 6px 16px;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-full);
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all var(--duration-fast) ease;
    background: var(--card-bg);
    font-family: inherit;
    white-space: nowrap;
}

.filter-tag:hover {
    border-color: var(--red);
    color: var(--red);
    background: var(--red-light);
}

.filter-tag.active {
    background: var(--red);
    color: var(--text-inverse);
    border-color: var(--red);
}

/* ---------- Article List ---------- */
.article-list {
    display: flex;
    flex-direction: column;
    gap: var(--space-lg);
    padding-bottom: var(--space-3xl);
}

/* ---------- Article Card ---------- */
.article-card {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: var(--space-xl) var(--space-xl);
    box-shadow: var(--shadow-sm);
    transition: transform var(--duration-normal) var(--ease-out),
        box-shadow var(--duration-normal) var(--ease-out);
    display: block;
    color: inherit;
    position: relative;
    overflow: hidden;
    opacity: 0;
    transform: translateY(24px);
}

.article-card.visible {
    opacity: 1;
    transform: translateY(0);
    transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out),
        box-shadow var(--duration-normal) var(--ease-out);
}

.article-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.article-card.visible:hover {
    transform: translateY(-6px);
}

.article-card::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--red), #FF6B6B);
    opacity: 0;
    transition: opacity var(--duration-normal) ease;
}

.article-card:hover::after {
    opacity: 1;
}

/* Card Header: tags + reading time */
.card-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-md);
    gap: var(--space-sm);
}

.card-tags {
    display: flex;
    gap: 6px;
    flex-wrap: wrap;
}

.card-tag {
    display: inline-block;
    padding: 2px 10px;
    font-size: 12px;
    font-weight: 600;
    border-radius: var(--radius-full);
    background: var(--red-light);
    color: var(--red);
    letter-spacing: 0.02em;
}

.card-reading-time {
    font-size: 13px;
    color: var(--text-tertiary);
    flex-shrink: 0;
    display: flex;
    align-items: center;
    gap: 4px;
}

/* Card Title */
.article-title {
    font-size: 22px;
    font-weight: 700;
    letter-spacing: -0.015em;
    line-height: 1.35;
    margin-bottom: var(--space-md);
    transition: color var(--duration-fast) ease;
}

.article-card:hover .article-title {
    color: var(--red);
}

/* Card Quote */
.article-quote {
    font-size: 15px;
    font-weight: 500;
    color: var(--red);
    background: var(--red-light);
    border-left: 3px solid var(--red);
    padding: var(--space-md) var(--space-md);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin-bottom: var(--space-md);
    line-height: 1.6;
    position: relative;
}

.article-quote::before {
    content: '❝';
    position: absolute;
    top: -2px;
    left: var(--space-md);
    font-size: 20px;
    opacity: 0.3;
}

/* Card Review */
.article-review {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: var(--space-md);
    padding-bottom: var(--space-md);
    border-bottom: 1px solid var(--border);
    line-height: 1.65;
}

.article-review strong {
    color: var(--text-primary);
    font-weight: 600;
}

/* Card Preview */
.article-preview {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.65;
    margin-bottom: var(--space-lg);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* Read More */
.read-more {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 600;
    color: var(--red);
    transition: gap var(--duration-normal) var(--ease-spring);
}

.article-card:hover .read-more {
    gap: 10px;
}

.read-more svg {
    transition: transform var(--duration-normal) var(--ease-spring);
}

.article-card:hover .read-more svg {
    transform: translateX(4px);
}

/* ---------- Empty State ---------- */
.empty-state {
    text-align: center;
    padding: var(--space-3xl) var(--space-lg);
    color: var(--text-tertiary);
}

.empty-state-icon {
    font-size: 48px;
    margin-bottom: var(--space-md);
}

.empty-state-text {
    font-size: 16px;
}

/* ==========================================
   DETAIL PAGE
   ========================================== */

.detail-wrapper {
    max-width: var(--max-width-detail);
    margin: 0 auto;
    padding: var(--space-lg) var(--space-lg) var(--space-3xl);
}

/* Detail Top Bar */
.detail-top-bar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-xl);
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-secondary);
    transition: color var(--duration-fast) ease;
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
}

.back-link:hover {
    color: var(--red);
}

.share-btn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 500;
    color: var(--text-secondary);
    padding: 6px 14px;
    border: 1px solid var(--border-strong);
    border-radius: var(--radius-full);
    cursor: pointer;
    background: var(--card-bg);
    font-family: inherit;
    transition: all var(--duration-fast) ease;
}

.share-btn:hover {
    border-color: var(--red);
    color: var(--red);
    background: var(--red-light);
}

/* Detail Article Container */
.detail-container {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: var(--space-2xl);
    box-shadow: var(--shadow-sm);
    animation: fadeIn 0.5s var(--ease-out);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(12px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Detail Meta */
.detail-meta {
    display: flex;
    align-items: center;
    gap: var(--space-md);
    margin-bottom: var(--space-lg);
    flex-wrap: wrap;
}

.detail-reading-time {
    font-size: 14px;
    color: var(--text-tertiary);
    display: flex;
    align-items: center;
    gap: 4px;
}

/* Detail Title */
.detail-title {
    font-size: 36px;
    font-weight: 800;
    letter-spacing: -0.025em;
    line-height: 1.25;
    margin-bottom: var(--space-lg);
}

/* Detail Quote */
.detail-quote {
    font-size: 16px;
    font-weight: 500;
    color: var(--red);
    background: var(--red-light);
    border-left: 4px solid var(--red);
    padding: var(--space-md) var(--space-lg);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    margin-bottom: var(--space-lg);
    line-height: 1.65;
    position: relative;
}

/* Detail Review */
.detail-review {
    font-size: 15px;
    color: var(--text-secondary);
    font-style: italic;
    margin-bottom: var(--space-xl);
    padding-bottom: var(--space-xl);
    border-bottom: 1px solid var(--border);
    line-height: 1.7;
}

.detail-review strong {
    color: var(--text-primary);
    font-style: normal;
}

/* TOC */
.toc {
    background: var(--bg-primary);
    border-radius: var(--radius-md);
    padding: var(--space-lg);
    margin-bottom: var(--space-xl);
    border: 1px solid var(--border);
}

.toc-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    cursor: pointer;
    user-select: none;
}

.toc-title {
    font-size: 14px;
    font-weight: 700;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.toc-toggle {
    font-size: 14px;
    color: var(--text-tertiary);
    transition: transform var(--duration-fast) ease;
}

.toc.collapsed .toc-toggle {
    transform: rotate(-90deg);
}

.toc-list {
    list-style: none;
    margin-top: var(--space-md);
}

.toc.collapsed .toc-list {
    display: none;
}

.toc-item {
    padding: 6px 0;
}

.toc-item.level-3 {
    padding-left: var(--space-lg);
}

.toc-link {
    font-size: 14px;
    color: var(--text-secondary);
    transition: color var(--duration-fast) ease;
    display: block;
}

.toc-link:hover {
    color: var(--red);
}

/* Detail Content — Article Body */
.detail-content {
    font-size: 17px;
    line-height: 1.85;
    color: var(--text-primary);
}

.detail-content p {
    margin-bottom: var(--space-lg);
}

.detail-content h2 {
    font-size: 24px;
    font-weight: 700;
    letter-spacing: -0.015em;
    margin-top: var(--space-2xl);
    margin-bottom: var(--space-md);
    padding-top: var(--space-md);
    border-top: 1px solid var(--border);
}

.detail-content h3 {
    font-size: 20px;
    font-weight: 600;
    margin-top: var(--space-xl);
    margin-bottom: var(--space-md);
}

.detail-content blockquote {
    border-left: 3px solid var(--red);
    padding-left: var(--space-md);
    color: var(--text-secondary);
    font-style: italic;
    margin: var(--space-lg) 0;
}

.detail-content code {
    font-family: "SF Mono", "Fira Code", Consolas, monospace;
    background: var(--bg-secondary);
    padding: 2px 6px;
    border-radius: 4px;
    font-size: 0.9em;
}

.detail-content pre {
    background: var(--bg-secondary);
    padding: var(--space-lg);
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: var(--space-lg) 0;
}

.detail-content pre code {
    background: none;
    padding: 0;
}

.detail-content ul,
.detail-content ol {
    padding-left: var(--space-lg);
    margin-bottom: var(--space-lg);
}

.detail-content li {
    margin-bottom: var(--space-sm);
}

/* ---------- Prev/Next Navigation ---------- */
.article-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-md);
    margin-top: var(--space-2xl);
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border);
}

.article-nav-link {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: var(--space-md);
    border-radius: var(--radius-md);
    border: 1px solid var(--border);
    transition: all var(--duration-fast) ease;
    background: var(--card-bg);
}

.article-nav-link:hover {
    border-color: var(--red);
    background: var(--red-light);
}

.article-nav-link.next {
    text-align: right;
    grid-column: 2;
}

.article-nav-label {
    font-size: 12px;
    font-weight: 600;
    color: var(--text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.article-nav-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

/* ---------- Back to Top ---------- */
.back-to-top {
    position: fixed;
    bottom: var(--space-xl);
    right: var(--space-xl);
    width: 44px;
    height: 44px;
    border-radius: var(--radius-full);
    background: var(--card-bg);
    color: var(--text-secondary);
    border: 1px solid var(--border-strong);
    box-shadow: var(--shadow-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    opacity: 0;
    pointer-events: none;
    transform: translateY(12px);
    transition: all var(--duration-normal) var(--ease-out);
    z-index: 100;
}

.back-to-top.visible {
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--red);
    color: white;
    border-color: var(--red);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

/* ---------- Toast ---------- */
.toast {
    position: fixed;
    bottom: var(--space-xl);
    left: 50%;
    transform: translateX(-50%) translateY(80px);
    background: var(--text-primary);
    color: var(--bg-primary);
    padding: var(--space-md) var(--space-lg);
    border-radius: var(--radius-full);
    font-size: 14px;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    opacity: 0;
    pointer-events: none;
    transition: all var(--duration-normal) var(--ease-spring);
    z-index: 3000;
    white-space: nowrap;
}

.toast.show {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
}

/* ---------- Footer ---------- */
.site-footer {
    text-align: center;
    padding: var(--space-xl) 0;
    color: var(--text-tertiary);
    font-size: 13px;
    border-top: 1px solid var(--border);
    max-width: var(--max-width);
    margin: 0 auto;
}

.site-footer a {
    color: var(--red);
    font-weight: 500;
}

/* ==========================================
   RESPONSIVE
   ========================================== */

@media (max-width: 768px) {
    :root {
        --nav-height: 52px;
    }

    .menu-toggle {
        display: flex;
    }

    .nav-actions .desktop-only {
        display: none;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 16px;
    }

    .article-card {
        padding: var(--space-lg);
    }

    .article-title {
        font-size: 19px;
    }

    .detail-container {
        padding: var(--space-lg);
        border-radius: var(--radius-md);
    }

    .detail-title {
        font-size: 28px;
    }

    .detail-content {
        font-size: 16px;
    }

    .detail-wrapper {
        padding: var(--space-md) var(--space-md) var(--space-2xl);
    }

    .article-nav {
        grid-template-columns: 1fr;
    }

    .article-nav-link.next {
        text-align: left;
        grid-column: 1;
    }

    .back-to-top {
        bottom: var(--space-md);
        right: var(--space-md);
    }
}

@media (max-width: 480px) {
    .hero {
        padding: var(--space-2xl) 0 var(--space-xl);
    }

    .hero-title {
        font-size: 30px;
    }

    .card-meta {
        flex-direction: column;
        align-items: flex-start;
    }

    .hero::before {
        width: 300px;
        height: 300px;
    }
}