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

/* ========== Light (default) ========== */
:root {
    --bg: #fafafa;
    --bg-soft: #f1f1f6;
    --surface: #ffffff;
    --text: #1a1a2e;
    --text-secondary: #6b7280;
    --accent: #6366f1;
    --accent-light: #eef2ff;
    --accent-dark: #4f46e5;
    --border: #e5e7eb;
    --shadow: 0 1px 3px rgba(0,0,0,.04), 0 1px 2px rgba(0,0,0,.06);
    --shadow-hover: 0 10px 30px rgba(0,0,0,.08), 0 4px 8px rgba(0,0,0,.04);
    --nav-bg: rgba(250,250,250,.8);
    --code-bg: #1a1a2e;
    --code-text: #e4e4e7;
    --overlay: rgba(0,0,0,.3);
}

/* ========== Dark ========== */
[data-theme="dark"] {
    --bg: #0f0f1a;
    --bg-soft: #1a1a2e;
    --surface: #1e1e32;
    --text: #ededf2;
    --text-secondary: #9ca3af;
    --accent: #818cf8;
    --accent-light: #1e1b4b;
    --accent-dark: #6366f1;
    --border: #2d2d4a;
    --shadow: 0 1px 3px rgba(0,0,0,.2), 0 1px 2px rgba(0,0,0,.3);
    --shadow-hover: 0 10px 30px rgba(0,0,0,.4), 0 4px 8px rgba(0,0,0,.2);
    --nav-bg: rgba(15,15,26,.85);
    --code-bg: #0a0a14;
    --code-text: #d4d4d8;
    --overlay: rgba(0,0,0,.5);
}

html { scroll-behavior: smooth; }

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Noto Sans SC", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    transition: background .35s, color .35s;
    overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
::selection { background: var(--accent); color: #fff; }

/* ========== Container ========== */
.container {
    width: 100%;
    max-width: 960px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ========== Navbar ========== */
.navbar {
    position: sticky;
    top: 0;
    z-index: 100;
    background: var(--nav-bg);
    backdrop-filter: blur(16px) saturate(1.4);
    -webkit-backdrop-filter: blur(16px) saturate(1.4);
    border-bottom: 1px solid var(--border);
    transition: background .35s, border .35s;
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 1.15rem;
    color: var(--text);
    transition: color .35s;
}

.logo svg { color: var(--accent); transition: color .35s; }

.nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-links a,
.nav-current {
    padding: 6px 16px;
    border-radius: 8px;
    font-size: .9rem;
    font-weight: 500;
    transition: background .25s;
}

.nav-links a:hover { background: var(--accent-light); }

.nav-current {
    background: var(--accent);
    color: #fff;
}

/* ========== Hero ========== */
.hero {
    padding: 72px 0 56px;
    position: relative;
}

.hero::after {
    content: '';
    position: absolute;
    top: -120px;
    right: -120px;
    width: 400px; height: 400px;
    background: radial-gradient(circle, color-mix(in srgb, var(--accent) 8%, transparent) 0%, transparent 70%);
    border-radius: 50%;
    pointer-events: none;
}

.hero-content { position: relative; max-width: 640px; }

.hero-badge {
    display: inline-block;
    padding: 4px 14px;
    border-radius: 20px;
    background: var(--accent-light);
    color: var(--accent);
    font-size: .82rem;
    font-weight: 600;
    margin-bottom: 20px;
    letter-spacing: .3px;
    transition: background .35s, color .35s;
}

.hero h1 {
    font-size: clamp(2.2rem, 5vw, 3.2rem);
    font-weight: 800;
    line-height: 1.15;
    letter-spacing: -.02em;
    margin-bottom: 20px;
    transition: color .35s;
}

.hero p {
    font-size: 1.05rem;
    color: var(--text-secondary);
    max-width: 500px;
    line-height: 1.8;
    margin-bottom: 24px;
    transition: color .35s;
}

.hero-meta {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: .9rem;
    color: var(--text-secondary);
    transition: color .35s;
}

.dot { opacity: .5; }

/* ========== Section ========== */
.section { padding: 40px 0 56px; }

.home-hero { padding: 48px 0 32px; }
.home-hero h1 { font-size: clamp(1.6rem, 4vw, 2.4rem); }
.home-section { padding: 16px 0 24px; }
.home-section .post-card { padding: 18px 20px; }
.home-section .report-card { padding: 12px 16px; gap: 12px; }
.home-section .report-icon { width: 38px; height: 38px; }
.home-section .report-icon svg { width: 20px; height: 20px; }
.home-section .report-info h3 { font-size: .92rem; }

.section-header {
    display: flex;
    align-items: baseline;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 24px;
}

.section-header h2 {
    font-size: 1.4rem;
    font-weight: 700;
}

.section-line {
    flex: 1;
    min-width: 40px;
    height: 2px;
    background: var(--border);
    border-radius: 2px;
}

.section-more {
    font-size: .88rem;
    font-weight: 600;
    color: var(--accent);
    white-space: nowrap;
    transition: opacity .25s;
}

.section-more:hover { opacity: .75; }

.section-sub {
    font-size: .92rem;
    color: var(--text-secondary);
    width: 100%;
}

/* ========== Filter Bar ========== */
.filter-bar {
    display: flex;
    gap: 8px;
    flex-wrap: wrap;
    margin-bottom: 28px;
}

.filter-btn {
    padding: 6px 18px;
    border: 1px solid var(--border);
    border-radius: 20px;
    background: transparent;
    font-size: .85rem;
    font-weight: 500;
    color: var(--text-secondary);
    cursor: pointer;
    transition: all .25s;
}

.filter-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.filter-btn.active {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

/* ========== Reports ========== */
.reports-grid {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.report-card {
    display: flex;
    align-items: center;
    gap: 16px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 18px 22px;
    transition: transform .2s, box-shadow .3s, border .35s, background .35s;
}

.report-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

.report-icon {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    border-radius: 10px;
    background: var(--accent-light);
    color: var(--accent);
    display: flex;
    align-items: center;
    justify-content: center;
}

.report-info {
    flex: 1;
    min-width: 0;
}

.report-info h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 4px;
}

.report-info h3 a { transition: color .25s; }
.report-info h3 a:hover { color: var(--accent); }

.report-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: .82rem;
    color: var(--text-secondary);
}

.report-course {
    padding: 1px 10px;
    border-radius: 10px;
    background: var(--accent-light);
    color: var(--accent);
    font-weight: 600;
    font-size: .78rem;
}

.report-actions {
    display: flex;
    gap: 8px;
    flex-shrink: 0;
}

.report-btn {
    padding: 6px 16px;
    border-radius: 8px;
    font-size: .84rem;
    font-weight: 600;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    transition: all .25s;
    white-space: nowrap;
}

.report-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
}

.download-btn {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

.download-btn:hover {
    background: var(--accent-dark) !important;
    border-color: var(--accent-dark) !important;
    color: #fff !important;
}

/* ========== Report Viewer (preview page) ========== */
.report-viewer {
    padding: 32px 0 48px;
}

.report-viewer-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 24px;
    flex-wrap: wrap;
}

.report-viewer-header h1 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 6px;
}

.report-viewer-meta {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: .85rem;
    color: var(--text-secondary);
}

.report-course-tag {
    padding: 2px 12px;
    border-radius: 10px;
    background: var(--accent-light);
    color: var(--accent);
    font-weight: 600;
    font-size: .8rem;
}

.report-viewer-actions {
    display: flex;
    gap: 8px;
}

.pdf-viewer {
    background: var(--bg-soft);
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--border);
    min-height: 70vh;
}

.pdf-embed {
    width: 100%;
    height: 85vh;
    display: block;
    border: none;
}

/* ========== Post Cards — 2-column grid ========== */
.posts-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.post-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 26px;
    transition: transform .25s, box-shadow .35s, border .35s, background .35s;
    display: flex;
    flex-direction: column;
}

.post-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.post-card h3 {
    font-size: 1.1rem;
    font-weight: 700;
    line-height: 1.4;
    margin-bottom: 10px;
    transition: color .35s;
}

.post-card h3 a { transition: color .25s; }
.post-card h3 a:hover { color: var(--accent); }

.post-card p {
    font-size: .9rem;
    color: var(--text-secondary);
    line-height: 1.7;
    flex: 1;
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
    transition: color .35s;
}

.card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 16px;
    padding-top: 14px;
    border-top: 1px solid var(--border);
    font-size: .82rem;
    color: var(--text-secondary);
    transition: border .35s, color .35s;
}

.read-time {
    padding: 2px 10px;
    border-radius: 8px;
    background: var(--bg-soft);
    font-weight: 500;
    transition: background .35s;
}

/* ========== Post Article ========== */
.post-article { padding: 48px 0 64px; }

.post-header {
    max-width: 680px;
    margin: 0 auto 40px;
    text-align: center;
}

.post-meta-top {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 16px;
}

.post-header h1 {
    font-size: clamp(1.6rem, 4vw, 2.4rem);
    font-weight: 800;
    line-height: 1.25;
    letter-spacing: -.02em;
    margin-bottom: 14px;
}

.post-meta {
    color: var(--text-secondary);
    font-size: .9rem;
}

.post-content {
    max-width: 680px;
    margin: 0 auto;
    font-size: 1.02rem;
    line-height: 1.85;
}

.post-content p { margin-bottom: 1.5em; }

.post-content h2 {
    font-size: 1.4rem;
    font-weight: 700;
    margin: 2em 0 .8em;
}

.post-content pre {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 20px 24px;
    border-radius: 10px;
    overflow-x: auto;
    font-size: .88rem;
    line-height: 1.6;
    margin: 1.5em 0;
    transition: background .35s, color .35s;
}

.post-content code {
    font-family: "JetBrains Mono", "Fira Code", monospace;
    font-size: .9em;
}

.post-content pre code { font-size: inherit; }

.post-content h3 {
    font-size: 1.15rem;
    font-weight: 700;
    margin: 1.8em 0 .6em;
}

.post-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5em 0;
    font-size: .92rem;
}

.post-content th,
.post-content td {
    border: 1px solid var(--border);
    padding: 10px 14px;
    text-align: left;
}

.post-content th {
    background: var(--bg-soft);
    font-weight: 600;
}

.post-content tr:nth-child(even) td {
    background: var(--bg-soft);
}

.post-content blockquote {
    border-left: 3px solid var(--accent);
    background: var(--accent-light);
    padding: 12px 16px;
    margin: 1.5em 0;
    border-radius: 0 8px 8px 0;
}

.post-content blockquote p { margin-bottom: .5em; }
.post-content blockquote p:last-child { margin-bottom: 0; }

.post-content hr {
    border: none;
    border-top: 1px solid var(--border);
    margin: 2em 0;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-weight: 600;
    color: var(--accent);
    transition: gap .25s;
}

.back-link:hover { gap: 10px; }

.post-footer-nav {
    max-width: 680px;
    margin: 48px auto 0;
    padding-top: 28px;
    border-top: 1px solid var(--border);
}

/* ========== 404 ========== */
.not-found {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 60vh;
    text-align: center;
}

.not-found h1 {
    font-size: 5rem;
    font-weight: 800;
    color: var(--accent);
    line-height: 1;
    margin-bottom: 8px;
}

.not-found p {
    color: var(--text-secondary);
    font-size: 1.1rem;
    margin-bottom: 24px;
}

/* ========== Floating Actions (右下角) ========== */
.fab-group {
    position: fixed;
    bottom: 28px;
    right: 28px;
    z-index: 200;
    display: flex;
    flex-direction: column-reverse;
    align-items: center;
    gap: 10px;
}

.fab-btn {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-secondary);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all .3s cubic-bezier(.4,0,.2,1), background .35s, border .35s, color .35s;
    box-shadow: var(--shadow);
    position: relative;
}

.fab-btn:hover {
    background: var(--accent);
    border-color: var(--accent);
    color: #fff;
}

.fab-btn .tooltip {
    position: absolute;
    right: calc(100% + 12px);
    white-space: nowrap;
    background: var(--text);
    color: var(--bg);
    font-size: .78rem;
    font-weight: 500;
    padding: 4px 12px;
    border-radius: 6px;
    opacity: 0;
    pointer-events: none;
    transition: opacity .2s;
}

.fab-btn:hover .tooltip { opacity: 1; }

/* visible / hidden states */
.fab-btn.hide {
    opacity: 0;
    transform: scale(.5);
    pointer-events: none;
}

/* ========== Footer ========== */
.footer {
    border-top: 1px solid var(--border);
    padding: 28px 0;
    margin-top: 24px;
    transition: border .35s;
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
    font-size: .86rem;
    color: var(--text-secondary);
    transition: color .35s;
}

.social-links {
    display: flex;
    gap: 10px;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 36px; height: 36px;
    border-radius: 50%;
    border: 1px solid var(--border);
    color: var(--text-secondary);
    transition: all .25s, border .35s, color .35s;
}

.social-links a:hover {
    border-color: var(--accent);
    color: var(--accent);
    background: var(--accent-light);
}

/* ========== Responsive ========== */

/* Tablet & small laptop */
@media (max-width: 900px) {
    .hero h1 { font-size: 2rem; }
    .report-actions { flex-direction: column; gap: 4px; }
    .report-card { flex-wrap: wrap; }
}

/* Mobile */
@media (max-width: 768px) {
    .hero { padding: 36px 0 28px; }
    .hero p { font-size: .95rem; }
    .section { padding: 24px 0 32px; }
    .posts-grid { grid-template-columns: 1fr; }
    .reports-grid { gap: 10px; }
    .report-card { padding: 14px 16px; gap: 12px; }
    .report-icon { width: 40px; height: 40px; }
    .report-icon svg { width: 22px; height: 22px; }
    .report-actions { flex-direction: row; }
    .report-info h3 { font-size: .92rem; }
    .report-meta { flex-wrap: wrap; gap: 6px; font-size: .78rem; }
    .report-btn { padding: 4px 12px; font-size: .78rem; }

    .fab-group { bottom: 16px; right: 16px; gap: 8px; }
    .fab-btn { width: 38px; height: 38px; }
    .fab-btn svg { width: 17px; height: 17px; }
    .fab-btn .tooltip { display: none; }

    .pdf-viewer { min-height: 50vh; }
    .pdf-embed { height: 60vh; }
    .report-viewer-header { flex-direction: column; }
    .report-viewer-actions { width: 100%; }
    .report-viewer-actions .report-btn { flex: 1; text-align: center; }

    .post-article { padding: 28px 0 40px; }
    .post-content { font-size: .95rem; }
    .post-content pre { padding: 14px 16px; font-size: .82rem; }
    .post-header h1 { font-size: 1.4rem; }

    .nav-links a,
    .nav-current { padding: 5px 12px; font-size: .82rem; }
}

/* Small phone */
@media (max-width: 480px) {
    .container { padding: 0 14px; }
    .hero h1 { font-size: 1.6rem; }
    .hero-badge { font-size: .75rem; }
    .section-header { gap: 8px; }
    .section-header h2 { font-size: 1.15rem; }
    .post-card { padding: 16px; }
    .post-card h3 { font-size: 1rem; }
    .report-actions { flex-direction: column; width: 100%; }
    .report-actions .report-btn { text-align: center; }
    .report-card { flex-direction: column; align-items: stretch; }
}