:root {
    color-scheme: light;
    --bg: #edf4f8;
    --panel: #ffffff;
    --panel-alt: #f4f8ff;
    --ink: #1a1a1a;
    --muted: #5a6573;
    --line: #d9e3ec;
    --accent: #0078d4;
    --accent-strong: #005ea6;
    --shadow: 0 18px 40px rgba(15, 23, 42, 0.08);
    --font-sans: "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: var(--font-sans);
    background:
        radial-gradient(circle at top left, rgba(0, 120, 212, 0.12), transparent 26%),
        radial-gradient(circle at top right, rgba(244, 248, 255, 0.95), transparent 30%),
        linear-gradient(180deg, #f9fcff 0%, var(--bg) 100%);
    color: var(--ink);
    line-height: 1.6;
}

a {
    color: var(--accent-strong);
}

a:hover {
    color: var(--accent);
}

.shell {
    width: min(1180px, calc(100% - 32px));
    margin: 0 auto;
}

.site-header {
    padding: 36px 0 24px;
}

.brand {
    display: inline-block;
    text-decoration: none;
    color: inherit;
}

.brand-copy {
    max-width: 760px;
}

.eyebrow {
    margin: 0 0 8px;
    font-size: 0.82rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--accent-strong);
    font-weight: 600;
}

.brand h1,
.page-hero h1 {
    margin: 0;
    font-size: clamp(2.4rem, 4vw, 4.2rem);
    line-height: 1.02;
    font-weight: 600;
    letter-spacing: -0.045em;
}

.brand-copy .lede {
    margin: 14px 0 0;
    max-width: 640px;
    font-size: 1.08rem;
    color: var(--muted);
}

.category-card h2,
.content-card h2,
.content-card h3,
.content-card h4,
.sidebar label,
.sidebar nav summary,
.sidebar nav strong {
    font-family: var(--font-sans);
}

.page-hero {
    margin-bottom: 28px;
    padding: 26px 30px;
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid rgba(217, 227, 236, 0.95);
    border-radius: 24px;
    box-shadow: var(--shadow);
    backdrop-filter: blur(6px);
}

.page-hero p,
.meta,
.crumbs {
    color: var(--muted);
}

.page-layout {
    display: grid;
    gap: 24px;
    grid-template-columns: minmax(0, 280px) minmax(0, 1fr);
    padding-bottom: 48px;
}

.home-intro {
    margin-bottom: 24px;
    padding: 28px 30px;
    background: linear-gradient(135deg, rgba(244, 248, 255, 0.96) 0%, rgba(255, 255, 255, 0.98) 58%, rgba(237, 244, 248, 0.95) 100%);
    border: 1px solid var(--line);
    border-radius: 24px;
    box-shadow: var(--shadow);
}

.home-intro h2 {
    margin: 0;
    font-size: clamp(1.7rem, 2.4vw, 2.4rem);
    line-height: 1.08;
    letter-spacing: -0.03em;
}

.home-intro p {
    margin: 12px 0 0;
    max-width: 700px;
    color: var(--muted);
}

.metric-row {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    margin-top: 20px;
}

.metric-chip {
    min-width: 132px;
    padding: 14px 16px;
    border: 1px solid var(--line);
    border-radius: 16px;
    background: rgba(255, 255, 255, 0.9);
}

.metric-chip strong {
    display: block;
    font-size: 1.2rem;
    line-height: 1.1;
}

.metric-chip span {
    display: block;
    margin-top: 4px;
    color: var(--muted);
    font-size: 0.92rem;
}

.sidebar,
.content-card,
.category-card {
    background: var(--panel);
    border: 1px solid var(--line);
    border-radius: 22px;
    box-shadow: var(--shadow);
}

.sidebar {
    position: sticky;
    top: 16px;
    padding: 20px;
    align-self: start;
    background: rgba(255, 255, 255, 0.94);
}

.sidebar input {
    width: 100%;
    padding: 12px 14px;
    font: inherit;
    color: inherit;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 14px;
}

.sidebar input:focus {
    outline: 2px solid rgba(0, 120, 212, 0.18);
    border-color: var(--accent);
}

.sidebar nav {
    margin-top: 18px;
    max-height: calc(100vh - 180px);
    overflow: auto;
    padding-right: 8px;
}

.sidebar nav details {
    border-top: 1px solid var(--line);
    padding: 10px 0;
}

.sidebar nav details:first-child {
    border-top: 0;
    padding-top: 0;
}

.sidebar nav summary {
    cursor: pointer;
    font-weight: 600;
    list-style: none;
}

.sidebar nav summary::-webkit-details-marker {
    display: none;
}

.sidebar nav ul,
.article-body ul,
.article-body ol {
    padding-left: 20px;
}

.sidebar nav li {
    margin: 8px 0;
}

.sidebar nav a {
    text-decoration: none;
}

.content-card {
    padding: 28px;
    min-width: 0;
}

.category-grid {
    display: grid;
    gap: 20px;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
}

.category-card {
    padding: 20px;
    background: var(--panel);
    border-top: 5px solid var(--accent);
}

.category-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 14px;
}

.category-card h2 {
    margin: 0;
}

.count-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 72px;
    padding: 8px 10px;
    border-radius: 999px;
    background: var(--panel-alt);
    color: var(--accent-strong);
    font-size: 0.88rem;
    font-weight: 600;
    white-space: nowrap;
}

.section-list {
    margin: 14px 0 0;
    padding: 0;
    list-style: none;
}

.section-list li {
    margin-top: 12px;
    padding-top: 12px;
    border-top: 1px solid var(--line);
}

.section-list li:first-child {
    margin-top: 0;
    padding-top: 0;
    border-top: 0;
}

.section-list a {
    font-weight: 500;
    text-decoration-thickness: 1px;
    text-underline-offset: 0.12em;
}

.article-list {
    margin-top: 24px;
    display: grid;
    gap: 14px;
}

.article-link {
    display: block;
    padding: 16px 18px;
    text-decoration: none;
    color: inherit;
    border: 1px solid var(--line);
    border-radius: 18px;
    background: var(--panel-alt);
    transition: transform 160ms ease, box-shadow 160ms ease, border-color 160ms ease;
}

.article-link:hover {
    border-color: var(--accent);
    transform: translateY(-1px);
    box-shadow: 0 10px 24px rgba(0, 120, 212, 0.12);
}

.article-link strong {
    display: block;
    margin-bottom: 4px;
}

.article-body {
    font-size: 1.05rem;
}

.article-body img {
    max-width: 100%;
    height: auto;
}

.article-body table {
    width: 100%;
    display: block;
    overflow-x: auto;
    border-collapse: collapse;
}

.article-body th,
.article-body td {
    border: 1px solid var(--line);
    padding: 8px 10px;
}

.panel-group .panel {
    margin-bottom: 14px;
    border: 1px solid var(--line);
    border-radius: 16px;
    overflow: hidden;
    background: #fff;
}

.panel-heading {
    background: linear-gradient(180deg, #f9fbff 0%, var(--panel-alt) 100%);
}

.panel-title {
    margin: 0;
    font-size: 1rem;
}

.panel-title a {
    display: block;
    padding: 14px 16px;
    text-decoration: none;
}

.panel-collapse {
    display: none;
}

.panel-collapse.in,
.panel-collapse.is-open {
    display: block;
}

.panel-body {
    padding: 16px;
}

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

    .sidebar {
        position: static;
    }

    .home-intro {
        padding: 24px;
    }
}