:root {
    --bg: #f8fafc;
    --surface: #ffffff;
    --surface-soft: #f1f5f9;
    --text: #0f172a;
    --muted: #64748b;
    --line: #e2e8f0;
    --brand: #111827;
    --brand-soft: #eef2ff;
    --brand-text: #3730a3;
    --radius-xl: 28px;
    --radius-lg: 22px;
    --shadow: 0 18px 45px rgba(15, 23, 42, .08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    background: var(--surface);
    color: var(--text);
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    text-rendering: optimizeLegibility;
}

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

.shell {
    width: min(1180px, calc(100% - 32px));
    margin-inline: auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    border-bottom: 1px solid rgba(226, 232, 240, .8);
    background: rgba(255, 255, 255, .86);
    backdrop-filter: blur(16px);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    min-height: 72px;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
}

.brand-icon {
    width: 42px;
    height: 42px;
    border-radius: 18px;
    background: #020617;
    color: #ffffff;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 10px 25px rgba(15, 23, 42, 0.18);
}
.brand strong,
.brand small { display: block; }

.brand strong { font-size: 16px; letter-spacing: -.02em; }
.brand small { margin-top: 2px; color: var(--muted); font-size: 12px; }

.main-nav {
    display: flex;
    align-items: center;
    gap: 6px;
}

.main-nav a {
    border-radius: 999px;
    padding: 10px 16px;
    color: var(--muted);
    font-size: 14px;
    font-weight: 700;
}

.main-nav a:hover { background: var(--surface-soft); color: var(--text); }

    .main-nav a.active {
        color: var(--ink);
        background: rgba(255, 255, 255, 0.75);
        box-shadow: 0 10px 24px rgba(15, 23, 42, 0.08);
    }

.hero {
    overflow: hidden;
    background:
        radial-gradient(circle at top left, #e0e7ff, transparent 34%),
        linear-gradient(180deg, #f8fafc 0%, #ffffff 100%);
}

.hero-inner {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 360px;
    gap: 42px;
    align-items: center;
    padding-block: 92px;
}

.hero-copy { max-width: 790px; }

.eyebrow,
.mini-label {
    display: inline-flex;
    align-items: center;
    width: fit-content;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: rgba(255,255,255,.75);
    padding: 8px 13px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 800;
}

.mini-label {
    border-color: transparent;
    background: var(--brand-soft);
    color: var(--brand-text);
    padding: 6px 11px;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: .05em;
}

.hero h1 {
    margin: 24px 0 0;
    max-width: 820px;
    font-size: clamp(46px, 7vw, 82px);
    line-height: .96;
    letter-spacing: -.065em;
}

.hero p {
    margin: 24px 0 0;
    max-width: 680px;
    color: var(--muted);
    font-size: 19px;
    line-height: 1.75;
}

.search-panel {
    display: flex;
    align-items: center;
    gap: 12px;
    max-width: 650px;
    margin-top: 34px;
    border: 1px solid var(--line);
    border-radius: 28px;
    background: var(--surface);
    padding: 12px;
    box-shadow: var(--shadow);
}

.search-icon {
    display: grid;
    width: 44px;
    height: 44px;
    flex: 0 0 44px;
    place-items: center;
    border-radius: 16px;
    background: var(--surface-soft);
    color: var(--muted);
    font-size: 26px;
}

.search-panel input,
.compact-search input {
    min-width: 0;
    width: 100%;
    border: 0;
    outline: 0;
    background: transparent;
    color: var(--text);
    font: inherit;
}

.search-panel button,
.compact-search button,
.soft-button {
    border: 0;
    border-radius: 18px;
    background: var(--brand);
    color: white;
    padding: 14px 22px;
    font-weight: 800;
    cursor: pointer;
    white-space: nowrap;
}

.hero-card {
    border: 1px solid rgba(226, 232, 240, .9);
    border-radius: 36px;
    background: rgba(255,255,255,.85);
    padding: 28px;
    box-shadow: var(--shadow);
}

.hero-card h2 {
    margin: 20px 0 0;
    font-size: 38px;
    letter-spacing: -.04em;
}

.hero-card p {
    margin-top: 14px;
    color: var(--muted);
    font-size: 16px;
    line-height: 1.7;
}

.text-link {
    display: inline-flex;
    margin-top: 20px;
    color: var(--text);
    font-weight: 800;
}

.section-block { padding-block: 66px; }

.section-head {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 24px;
    margin-bottom: 28px;
}

.section-head h2,
.filter-panel h1,
.detail-head h1 {
    margin: 10px 0 0;
    font-size: 38px;
    line-height: 1.08;
    letter-spacing: -.045em;
}

.section-head p,
.filter-panel p,
.detail-head p {
    margin: 10px 0 0;
    color: var(--muted);
    line-height: 1.7;
}

.soft-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border: 1px solid var(--line);
    background: var(--surface);
    color: var(--text);
    box-shadow: none;
}

.soft-button:hover { background: var(--surface-soft); }

.word-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
}

.word-grid.two-col { grid-template-columns: repeat(2, minmax(0, 1fr)); }

.word-card {
    position: relative;
    min-height: 230px;
    border: 1px solid var(--line);
    border-radius: var(--radius-xl);
    background: var(--surface);
    padding: 24px;
    box-shadow: 0 1px 0 rgba(15,23,42,.02);
    transition: transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}

.word-card:hover {
    transform: translateY(-4px);
    border-color: #cbd5e1;
    box-shadow: var(--shadow);
}

.word-card-top {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 28px;
}

.pill,
.count-badge {
    display: inline-flex;
    border-radius: 999px;
    background: var(--surface-soft);
    padding: 6px 11px;
    color: var(--muted);
    font-size: 12px;
    font-weight: 800;
}

.arrow { color: #cbd5e1; font-weight: 900; }

.word-card h3 {
    margin: 0;
    font-size: 28px;
    letter-spacing: -.035em;
}

.word-card p {
    margin: 12px 0 0;
    min-height: 72px;
    color: var(--muted);
    line-height: 1.7;
}

.card-link { position: absolute; inset: 0; border-radius: inherit; }

.page-bg { background: var(--bg); min-height: calc(100vh - 144px); }

.list-layout,
.detail-layout {
    display: grid;
    grid-template-columns: 320px minmax(0, 1fr);
    gap: 28px;
    padding-block: 42px;
}

.filter-panel,
.toc-card {
    position: sticky;
    top: 96px;
    height: fit-content;
    border: 1px solid var(--line);
    border-radius: 32px;
    background: var(--surface);
    padding: 24px;
    box-shadow: 0 1px 0 rgba(15,23,42,.02);
}

.compact-search {
    display: flex;
    gap: 8px;
    margin-top: 22px;
    border-radius: 22px;
    background: var(--surface-soft);
    padding: 8px;
}

.compact-search input { padding-inline: 10px; }
.compact-search button { padding: 11px 14px; border-radius: 15px; }

.filter-links { margin-top: 20px; display: grid; gap: 6px; }
.filter-links a,
.toc-card > a {
    display: block;
    border-radius: 16px;
    padding: 11px 13px;
    color: var(--muted);
    font-weight: 700;
}
.filter-links a:hover,
.filter-links a.active,
.toc-card > a:hover { background: var(--surface-soft); color: var(--text); }

.section-head.slim { margin-bottom: 18px; }

.pagination-wrap {
    margin-top: 24px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.detail-layout { grid-template-columns: minmax(0, 1fr) 300px; align-items: start; }

.detail-card {
    border: 1px solid var(--line);
    border-radius: 36px;
    background: var(--surface);
    padding: clamp(26px, 5vw, 52px);
    box-shadow: 0 1px 0 rgba(15,23,42,.02);
}

.back-link {
    display: inline-flex;
    margin-bottom: 30px;
    border-radius: 999px;
    background: var(--surface-soft);
    padding: 10px 14px;
    color: var(--muted);
    font-weight: 800;
}

.detail-head { margin-bottom: 36px; }
.detail-head h1 { font-size: clamp(40px, 6vw, 64px); }
.detail-head p { max-width: 720px; font-size: 19px; }

.post-content {
    color: #334155;
    font-size: 18px;
    line-height: 1.85;
}

.post-content > *:first-child { margin-top: 0; }

.post-content h1,
.post-content h2,
.post-content h3 {
    color: var(--text);
    line-height: 1.15;
    letter-spacing: -.035em;
}

.post-content h1 { font-size: 44px; margin: 0 0 24px; }
.post-content h2 { font-size: 30px; margin: 42px 0 12px; padding-top: 20px; border-top: 1px solid var(--line); }
.post-content h3 { font-size: 23px; margin: 30px 0 10px; }

.post-content p { margin: 12px 0; }
.post-content ul,
.post-content ol { padding-left: 24px; margin: 16px 0; }
.post-content li { margin: 8px 0; }

.post-content a {
    color: #4338ca;
    font-weight: 800;
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-underline-offset: 4px;
}

.post-content blockquote {
    margin: 24px 0;
    border-left: 4px solid #c7d2fe;
    border-radius: 18px;
    background: #eef2ff;
    padding: 16px 20px;
    color: #3730a3;
}

.post-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 24px 0;
    overflow: hidden;
    border-radius: 18px;
}

.post-content th,
.post-content td {
    border: 1px solid var(--line);
    padding: 12px 14px;
    text-align: left;
}

.post-content th { background: var(--surface-soft); color: var(--text); }

.toc-card h2 {
    margin: 0 0 12px;
    font-size: 18px;
}

.related-box {
    margin-top: 24px;
    border-radius: 24px;
    background: var(--surface-soft);
    padding: 16px;
}

.related-box div {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 12px;
}

.related-box div a {
    border-radius: 999px;
    background: white;
    padding: 7px 10px;
    color: var(--muted);
    font-size: 13px;
    font-weight: 800;
}

.site-footer {
    border-top: 1px solid var(--line);
    background: var(--surface);
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    padding-block: 28px;
    color: var(--muted);
    font-size: 14px;
}

@media (max-width: 900px) {
    .hero-inner,
    .list-layout,
    .detail-layout { grid-template-columns: 1fr; }
    .hero-inner { padding-block: 58px; }
    .hero-card,
    .filter-panel,
    .toc-card { position: static; }
    .word-grid,
    .word-grid.two-col { grid-template-columns: 1fr; }
    .section-head { align-items: start; flex-direction: column; }
}

@media (max-width: 620px) {
    .main-nav { display: none; }
    .search-panel { align-items: stretch; flex-direction: column; }
    .search-icon { display: none; }
    .search-panel input { padding: 12px; }
    .search-panel button { width: 100%; }
    .footer-inner { flex-direction: column; }
}

.ad-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    justify-items: center;
}

@media (max-width: 900px) {
    .ad-grid {
        grid-template-columns: 1fr;
    }
}