/* ========================================
   AI Pulse — Global AI Intelligence
   Design System v2.0
   ======================================== */

/* ---------- Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Noto+Sans+SC:wght@300;400;500;700&family=JetBrains+Mono:wght@400;500&display=swap');

/* ---------- Design Tokens ---------- */
:root {
    /* Background */
    --bg-primary: #09090b;
    --bg-secondary: #0c0c10;
    --bg-card: rgba(255, 255, 255, 0.02);
    --bg-card-hover: rgba(255, 255, 255, 0.04);
    --bg-surface: rgba(255, 255, 255, 0.03);

    /* Text */
    --text-primary: #fafafa;
    --text-secondary: #a1a1aa;
    --text-muted: #52525b;
    --text-accent: #00D4AA;

    /* Accent */
    --accent: #00D4AA;
    --accent-secondary: #7B61FF;
    --accent-glow: rgba(0, 212, 170, 0.15);
    --accent-glow-strong: rgba(0, 212, 170, 0.3);

    /* Category Colors */
    --cat-llm: #00D4AA;
    --cat-safety: #F472B6;
    --cat-research: #818CF8;
    --cat-agents: #FB923C;
    --cat-vision: #38BDF8;
    --cat-default: #A1A1AA;

    /* Border */
    --border: rgba(255, 255, 255, 0.06);
    --border-hover: rgba(255, 255, 255, 0.12);
    --border-accent: rgba(0, 212, 170, 0.2);

    /* Typography */
    --font-sans: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Cascadia Code', monospace;

    /* Spacing & Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;
    --radius-xl: 20px;

    /* Shadows */
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
    --shadow-md: 0 4px 20px rgba(0,0,0,0.4);
    --shadow-lg: 0 8px 40px rgba(0,0,0,0.5);
    --shadow-glow: 0 0 30px var(--accent-glow);

    /* Transitions */
    --ease: cubic-bezier(0.4, 0, 0.2, 1);
    --duration: 0.25s;
}

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

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

body {
    font-family: var(--font-sans);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: color var(--duration) var(--ease);
}

/* ---------- Background Effects ---------- */
.bg-grid {
    position: fixed;
    inset: 0;
    background-image:
        linear-gradient(rgba(255,255,255,0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(255,255,255,0.02) 1px, transparent 1px);
    background-size: 60px 60px;
    pointer-events: none;
    z-index: 0;
    mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 30%, transparent 100%);
    -webkit-mask-image: radial-gradient(ellipse 80% 60% at 50% 0%, black 30%, transparent 100%);
}

.bg-glow {
    position: fixed;
    border-radius: 50%;
    filter: blur(120px);
    pointer-events: none;
    z-index: 0;
}

.bg-glow-1 {
    width: 600px;
    height: 600px;
    background: var(--accent);
    opacity: 0.06;
    top: -200px;
    right: -100px;
    animation: glowDrift 25s ease-in-out infinite;
}

.bg-glow-2 {
    width: 500px;
    height: 500px;
    background: var(--accent-secondary);
    opacity: 0.04;
    bottom: -200px;
    left: -150px;
    animation: glowDrift 30s ease-in-out infinite reverse;
}

@keyframes glowDrift {
    0%, 100% { transform: translate(0, 0); }
    50% { transform: translate(40px, -30px); }
}

/* ---------- Navbar ---------- */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(9, 9, 11, 0.7);
    backdrop-filter: blur(24px) saturate(180%);
    -webkit-backdrop-filter: blur(24px) saturate(180%);
    border-bottom: 1px solid transparent;
    padding: 0 2rem;
    transition: all var(--duration) var(--ease);
}

.navbar.scrolled {
    border-bottom-color: var(--border);
    background: rgba(9, 9, 11, 0.9);
}

.navbar-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.navbar-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    color: var(--text-primary);
}

.logo-mark {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.navbar-links {
    display: flex;
    gap: 2rem;
    align-items: center;
}

.navbar-links a {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-muted);
    padding: 4px 0;
    position: relative;
    transition: color var(--duration) var(--ease);
}

.navbar-links a:hover,
.navbar-links a.active {
    color: var(--text-primary);
}

.navbar-links a.active::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 100%;
    height: 1px;
    background: var(--accent);
}

.navbar-actions {
    display: flex;
    align-items: center;
}

.nav-sync-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    background: transparent;
    color: var(--accent);
    border: 1px solid var(--border-accent);
    padding: 6px 14px;
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 500;
    cursor: pointer;
    font-family: var(--font-mono);
    transition: all var(--duration) var(--ease);
}

.nav-sync-btn:hover {
    background: var(--accent-glow);
    border-color: var(--accent);
    box-shadow: var(--shadow-glow);
}

.nav-sync-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.sync-icon {
    font-size: 0.9rem;
    display: inline-block;
}

.spinning {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* ---------- Hero ---------- */
.hero {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 6rem 2rem 4rem;
}

.hero-content {
    max-width: 720px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    font-size: 0.78rem;
    font-weight: 500;
    color: var(--accent);
    font-family: var(--font-mono);
    margin-bottom: 2rem;
    animation: fadeIn 0.8s var(--ease);
}

.badge-dot {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; box-shadow: 0 0 0 0 var(--accent-glow-strong); }
    50% { opacity: 0.6; box-shadow: 0 0 0 6px transparent; }
}

.hero h1 {
    font-size: 3.8rem;
    font-weight: 800;
    letter-spacing: -2px;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

.hero-line-1 {
    display: block;
    color: var(--text-secondary);
    font-size: 0.55em;
    font-weight: 400;
    letter-spacing: -0.5px;
    margin-bottom: 0.15em;
    animation: fadeIn 0.8s var(--ease) 0.1s backwards;
}

.hero-line-2 {
    display: block;
    background: linear-gradient(135deg, var(--accent), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: fadeIn 0.8s var(--ease) 0.2s backwards;
}

.hero-desc {
    font-size: 1rem;
    color: var(--text-muted);
    line-height: 1.8;
    max-width: 520px;
    margin-bottom: 2.5rem;
    animation: fadeIn 0.8s var(--ease) 0.3s backwards;
}

.hero-metrics {
    display: flex;
    align-items: center;
    gap: 2rem;
    animation: fadeIn 0.8s var(--ease) 0.4s backwards;
}

.metric {
    display: flex;
    flex-direction: column;
}

.metric-value {
    font-size: 1.5rem;
    font-weight: 700;
    font-family: var(--font-mono);
    color: var(--text-primary);
}

.metric-label {
    font-size: 0.72rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-top: 2px;
}

.metric-divider {
    width: 1px;
    height: 36px;
    background: var(--border);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(12px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ---------- Toolbar ---------- */
.toolbar {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem 1.5rem;
}

.toolbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
}

.toolbar-label {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 1.5px;
}

.import-group {
    display: flex;
    gap: 0;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: border-color var(--duration) var(--ease);
}

.import-group:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.toolbar-input {
    background: transparent;
    border: none;
    outline: none;
    color: var(--text-primary);
    padding: 8px 14px;
    font-size: 0.82rem;
    width: 280px;
    font-family: var(--font-mono);
}

.toolbar-input::placeholder {
    color: var(--text-muted);
}

.toolbar-btn {
    background: var(--bg-surface);
    color: var(--text-secondary);
    border: none;
    border-left: 1px solid var(--border);
    padding: 8px 16px;
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--duration) var(--ease);
    font-family: var(--font-sans);
}

.toolbar-btn:hover {
    background: var(--accent-glow);
    color: var(--accent);
}

.toolbar-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* ---------- Main Layout ---------- */
.main-content {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 2rem 4rem;
    display: grid;
    grid-template-columns: 1fr 300px;
    gap: 3rem;
}

/* ---------- Feed Cards ---------- */
.feed-section {
    display: flex;
    flex-direction: column;
    gap: 0;
}

.feed-card {
    position: relative;
    padding: 2rem 0;
    border-bottom: 1px solid var(--border);
    transition: all var(--duration) var(--ease);
    cursor: pointer;
}

.feed-card:first-child {
    padding-top: 0;
}

.feed-card:hover {
    padding-left: 1rem;
}

.feed-card:hover .feed-card-index {
    color: var(--accent);
    opacity: 0.3;
}

.feed-card-meta {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-bottom: 0.75rem;
    font-size: 0.78rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

.feed-source {
    color: var(--text-secondary);
    font-weight: 500;
}

.feed-dot {
    opacity: 0.3;
}

.feed-category {
    margin-left: auto;
    padding: 2px 8px;
    border-radius: 100px;
    font-size: 0.68rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
    background: var(--accent-glow);
    color: var(--accent);
}

.feed-title {
    font-size: 1.35rem;
    font-weight: 700;
    letter-spacing: -0.5px;
    line-height: 1.35;
    margin-bottom: 0.3rem;
    color: var(--text-primary);
    transition: color var(--duration) var(--ease);
}

.feed-card:hover .feed-title {
    color: var(--accent);
}

.feed-title-en {
    font-size: 0.88rem;
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 0.85rem;
    line-height: 1.4;
    opacity: 0.7;
}

.feed-summary {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 0.4rem;
}

.feed-summary-en {
    font-size: 0.82rem;
    color: var(--text-muted);
    line-height: 1.6;
    padding-left: 14px;
    border-left: 2px solid var(--border);
    margin-bottom: 1rem;
    opacity: 0.6;
}

.feed-card-footer {
    display: flex;
    align-items: center;
}

.feed-link {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--accent);
    font-family: var(--font-mono);
    opacity: 0;
    transform: translateX(-8px);
    transition: all var(--duration) var(--ease);
}

.feed-card:hover .feed-link {
    opacity: 1;
    transform: translateX(0);
}

.feed-card-index {
    position: absolute;
    top: 2rem;
    right: 0;
    font-size: 3rem;
    font-weight: 800;
    color: var(--text-muted);
    opacity: 0.08;
    font-family: var(--font-mono);
    line-height: 1;
    transition: all var(--duration) var(--ease);
    pointer-events: none;
}

/* Feed Title Link */
.feed-title-link {
    text-decoration: none;
    color: inherit;
}

.feed-detail-link {
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--accent);
    font-family: var(--font-mono);
    margin-right: 1.5rem;
    opacity: 0;
    transform: translateX(-8px);
    transition: all var(--duration) var(--ease);
}

.feed-card:hover .feed-detail-link {
    opacity: 1;
    transform: translateX(0);
}

/* Empty State */
.feed-empty {
    text-align: center;
    padding: 5rem 2rem;
    animation: fadeIn 1s var(--ease);
}

.empty-icon {
    font-size: 3rem;
    color: var(--accent);
    margin-bottom: 1.5rem;
    animation: pulse 2s ease-in-out infinite;
}

.empty-text {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-secondary);
    margin-bottom: 0.5rem;
    font-family: var(--font-mono);
}

.empty-hint {
    font-size: 0.85rem;
    color: var(--text-muted);
}

/* ---------- Post Detail Page ---------- */
.post-detail {
    position: relative;
    z-index: 1;
    max-width: 780px;
    margin: 0 auto;
    padding: 3rem 2rem 5rem;
}

.post-header {
    padding-bottom: 2.5rem;
    border-bottom: 1px solid var(--border);
    margin-bottom: 2.5rem;
}

.post-meta-bar {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.8rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
    margin-bottom: 1.5rem;
}

.post-meta-category {
    color: var(--accent);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.post-meta-sep {
    opacity: 0.3;
}

.post-detail-title {
    font-size: 2.2rem;
    font-weight: 800;
    letter-spacing: -1px;
    line-height: 1.25;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
}

.post-detail-title-en {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-style: italic;
    margin-bottom: 2rem;
    line-height: 1.4;
    opacity: 0.7;
}

.post-detail-summary {
    font-size: 1.05rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 0.75rem;
    padding: 1.25rem 1.5rem;
    background: var(--bg-surface);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--accent);
}

.post-detail-summary-en {
    font-size: 0.92rem;
    color: var(--text-muted);
    line-height: 1.7;
    padding: 1rem 1.5rem;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    border-left: 3px solid var(--border);
    margin-bottom: 2rem;
    font-style: italic;
}

.post-actions {
    margin-top: 1.5rem;
}

.btn-source {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: transparent;
    color: var(--accent);
    border: 1px solid var(--border-accent);
    padding: 10px 20px;
    border-radius: 100px;
    font-size: 0.85rem;
    font-weight: 500;
    font-family: var(--font-mono);
    transition: all var(--duration) var(--ease);
    text-decoration: none;
}

.btn-source:hover {
    background: var(--accent-glow);
    border-color: var(--accent);
    box-shadow: var(--shadow-glow);
}

/* Post Body */
.post-body {
    margin-bottom: 3rem;
}

.post-content {
    font-size: 1rem;
    color: var(--text-secondary);
    line-height: 1.85;
}

.post-content h1,
.post-content h2,
.post-content h3 {
    color: var(--text-primary);
    margin: 2rem 0 1rem;
    font-weight: 700;
    letter-spacing: -0.3px;
}

.post-content h2 {
    font-size: 1.5rem;
}

.post-content h3 {
    font-size: 1.2rem;
}

.post-content p {
    margin-bottom: 1.2rem;
}

/* 双语对照段落样式 */
.post-content .translated-p {
    font-size: 1.05rem;
    color: var(--text-primary);
    line-height: 1.8;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

.post-content .original-p {
    font-size: 0.95rem;
    color: var(--text-muted);
    font-style: italic;
    line-height: 1.6;
    margin-bottom: 1.5rem;
    padding-left: 1rem;
    border-left: 2px solid var(--border);
}

.post-content a {
    color: var(--accent);
    text-decoration: underline;
    text-underline-offset: 3px;
}

.post-content code {
    font-family: var(--font-mono);
    font-size: 0.88em;
    background: var(--bg-surface);
    padding: 2px 6px;
    border-radius: 4px;
    color: var(--accent);
}

.post-content pre {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    overflow-x: auto;
    margin: 1.5rem 0;
}

.post-content pre code {
    background: none;
    padding: 0;
    color: var(--text-secondary);
}

.post-content img {
    max-width: 100%;
    border-radius: var(--radius-md);
    margin: 1.5rem 0;
}

.post-content blockquote {
    border-left: 3px solid var(--accent);
    padding: 0.75rem 1.25rem;
    margin: 1.5rem 0;
    color: var(--text-muted);
    font-style: italic;
    background: var(--bg-surface);
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.post-content ul,
.post-content ol {
    padding-left: 1.5rem;
    margin-bottom: 1.2rem;
}

.post-content li {
    margin-bottom: 0.5rem;
    list-style: disc;
}

/* Post Footer */
.post-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.back-link {
    font-size: 0.85rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
    transition: color var(--duration) var(--ease);
}

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

.source-link {
    font-size: 0.85rem;
    color: var(--accent);
    font-family: var(--font-mono);
}

.source-link:hover {
    color: var(--text-primary);
}

/* ---------- Sidebar ---------- */
.sidebar {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    position: sticky;
    top: 80px;
    align-self: start;
}

.sidebar-panel {
    padding: 1.25rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    background: var(--bg-card);
    transition: border-color var(--duration) var(--ease);
}

.sidebar-panel:hover {
    border-color: var(--border-hover);
}

.panel-title {
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 8px;
}

.panel-icon {
    color: var(--accent);
    font-size: 0.7rem;
}

/* Source List */
.source-list {
    display: flex;
    flex-direction: column;
    gap: 0.65rem;
}

.source-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 10px;
    border-radius: var(--radius-sm);
    transition: background var(--duration) var(--ease);
    cursor: default;
}

.source-item:hover {
    background: var(--bg-card-hover);
}

.source-status {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--text-muted);
    flex-shrink: 0;
}

.source-status.active {
    background: var(--accent);
    box-shadow: 0 0 6px var(--accent-glow-strong);
}

.source-info {
    display: flex;
    flex-direction: column;
}

.source-name {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-primary);
}

.source-url {
    font-size: 0.72rem;
    color: var(--text-muted);
    font-family: var(--font-mono);
}

/* Topic Tags */
.topic-cloud {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.topic-tag {
    font-size: 0.75rem;
    padding: 4px 10px;
    border-radius: 100px;
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-muted);
    font-family: var(--font-mono);
    transition: all var(--duration) var(--ease);
    cursor: pointer;
}

.topic-tag:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-glow);
}

/* About Panel */
.about-text {
    font-size: 0.82rem;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 0.5rem;
}

.about-text-en {
    font-size: 0.78rem;
    color: var(--text-muted);
    line-height: 1.5;
    font-style: italic;
}

/* ---------- Footer ---------- */
.footer {
    position: relative;
    z-index: 1;
    border-top: 1px solid var(--border);
    padding: 2rem;
}

.footer-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.footer-left, .footer-right {
    font-size: 0.78rem;
    color: var(--text-muted);
}

.footer a {
    color: var(--accent);
}

.footer a:hover {
    color: var(--text-primary);
}

/* ---------- Responsive ---------- */
@media (max-width: 960px) {
    .main-content {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: static;
        display: grid;
        grid-template-columns: 1fr 1fr;
        gap: 1rem;
    }

    .hero h1 {
        font-size: 2.8rem;
    }

    .toolbar-input {
        width: 200px;
    }

    .feed-card-index {
        display: none;
    }
}

@media (max-width: 640px) {
    .navbar-links {
        display: none;
    }

    .hero {
        padding: 3rem 1.5rem 2rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero-metrics {
        flex-wrap: wrap;
        gap: 1.5rem;
    }

    .metric-divider {
        display: none;
    }

    .sidebar {
        grid-template-columns: 1fr;
    }

    .toolbar-input {
        width: 140px;
    }

    .import-group {
        width: 100%;
    }

    .toolbar-inner {
        flex-direction: column;
        align-items: flex-start;
        gap: 1rem;
    }

    .footer-inner {
        flex-direction: column;
        gap: 0.5rem;
        text-align: center;
    }
}