:root {
    --text: #0f172a;
    --muted: #475569;
    --light: #64748b;
    --border: #e2e8f0;
    --bg: #f8fafc;
    --card: #ffffff;
    --accent: #2563eb;
    --accent-dark: #1d4ed8;
    --accent-soft: #dbeafe;
    --shadow: 0 10px 30px rgba(15, 23, 42, 0.08);
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.7;
}

a {
    color: var(--accent);
    text-decoration: none;
}

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

.container {
    width: min(1120px, calc(100% - 32px));
    margin: 0 auto;
}

.site-header {
    position: sticky;
    top: 0;
    z-index: 20;
    background: rgba(248, 250, 252, 0.88);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.9);
}

.site-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 18px 0;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 12px;
    color: var(--text);
    font-weight: 800;
    font-size: 22px;
}

.brand img {
    width: 44px;
    height: 44px;
    object-fit: contain;
}

.nav {
    display: flex;
    align-items: center;
    gap: 18px;
}

.nav a {
    color: var(--muted);
    font-weight: 600;
}

.btn-primary,
.btn-secondary {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    border-radius: 999px;
    padding: 12px 22px;
    font-weight: 700;
    transition: transform 0.2s ease, background 0.2s ease;
}

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

.btn-primary:hover {
    background: var(--accent-dark);
    color: #fff;
    transform: translateY(-1px);
}

.btn-secondary {
    background: #fff;
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    transform: translateY(-1px);
}

.hero {
    padding: 72px 0 44px;
}

.hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 28px;
    align-items: stretch;
}

.hero-copy,
.hero-card,
.card,
.article-shell {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 28px;
    box-shadow: var(--shadow);
}

.hero-copy {
    padding: 40px;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: var(--accent-soft);
    color: var(--accent-dark);
    font-size: 13px;
    font-weight: 700;
    border-radius: 999px;
    padding: 8px 12px;
}

.hero h1 {
    font-size: clamp(36px, 5vw, 56px);
    line-height: 1.08;
    letter-spacing: -1.5px;
    margin: 18px 0 18px;
}

.hero p {
    color: var(--muted);
    font-size: 18px;
    margin: 0 0 28px;
}

.hero-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.hero-card {
    padding: 32px;
    background: linear-gradient(160deg, #eff6ff 0%, #ffffff 52%, #dbeafe 100%);
}

.hero-card h2 {
    margin: 0 0 14px;
    font-size: 24px;
}

.hero-card p,
.card p,
.article-meta,
.article-shell p,
.article-shell li {
    color: var(--muted);
}

.hero-points,
.toc,
.article-shell ul,
.article-shell ol {
    padding-left: 20px;
}

.section {
    padding: 0 0 36px;
}

.section-header {
    display: flex;
    align-items: end;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 20px;
}

.section-title {
    font-size: 30px;
    letter-spacing: -1px;
    margin: 0;
}

.section-subtitle {
    margin: 8px 0 0;
    color: var(--muted);
}

.grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 22px;
}

.card {
    padding: 28px;
}

.card .tag {
    display: inline-block;
    margin-bottom: 16px;
    background: #eff6ff;
    color: var(--accent-dark);
    border-radius: 999px;
    padding: 6px 10px;
    font-size: 12px;
    font-weight: 700;
}

.card h3 {
    margin: 0 0 12px;
    font-size: 22px;
    line-height: 1.3;
}

.card p {
    margin: 0 0 18px;
}

.card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    color: var(--light);
    font-size: 14px;
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 16px;
}

.topic-chip {
    padding: 18px;
    background: #fff;
    border: 1px solid var(--border);
    border-radius: 18px;
    color: var(--text);
    font-weight: 700;
    box-shadow: 0 6px 20px rgba(15, 23, 42, 0.04);
}

.article-page {
    padding: 48px 0 72px;
}

.breadcrumbs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 18px;
    color: var(--light);
    font-size: 14px;
}

.article-shell {
    padding: 42px;
    max-width: 820px;
    margin: 0 auto;
}

.article-shell h1 {
    font-size: clamp(34px, 5vw, 52px);
    line-height: 1.12;
    letter-spacing: -1.2px;
    margin: 12px 0 18px;
}

.article-shell h2 {
    margin-top: 36px;
    margin-bottom: 14px;
    font-size: 28px;
    letter-spacing: -0.6px;
}

.article-shell h3 {
    margin-top: 26px;
    margin-bottom: 10px;
    font-size: 22px;
}

.article-shell blockquote {
    margin: 24px 0;
    padding: 18px 20px;
    border-left: 4px solid var(--accent);
    background: #eff6ff;
    color: #1e3a8a;
    border-radius: 14px;
}

.article-shell strong {
    color: var(--text);
}

.article-cta {
    margin-top: 36px;
    padding: 26px;
    border-radius: 24px;
    background: linear-gradient(135deg, #eff6ff 0%, #ffffff 55%, #dbeafe 100%);
    border: 1px solid #bfdbfe;
}

.site-footer {
    padding: 24px 0 56px;
    text-align: center;
    color: var(--light);
    font-size: 14px;
}

@media (max-width: 960px) {
    .hero-grid,
    .grid,
    .topic-grid {
        grid-template-columns: 1fr;
    }

    .section-header,
    .site-header-inner {
        align-items: start;
        flex-direction: column;
    }
}

@media (max-width: 640px) {
    .hero-copy,
    .hero-card,
    .card,
    .article-shell {
        padding: 24px;
        border-radius: 22px;
    }

    .nav {
        flex-wrap: wrap;
    }
}