:root {
    color-scheme: light dark;
    --bg: #f4f7fb;
    --paper: #ffffff;
    --ink: #172033;
    --muted: #657086;
    --line: #dfe6f0;
    --accent: #0f8b8d;
    --accent-dark: #0a686a;
    --soft: #e9f6f6;
    --warn: #fff4dd;
    --shadow: 0 22px 60px rgba(30, 47, 76, .12);
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #111827;
        --paper: #182235;
        --ink: #eef4ff;
        --muted: #aab7ca;
        --line: #2d3a50;
        --accent: #2fc3bd;
        --accent-dark: #80e1dd;
        --soft: #142f35;
        --warn: #332917;
        --shadow: 0 22px 60px rgba(0, 0, 0, .34);
    }
}

* { box-sizing: border-box; }

body {
    margin: 0;
    font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
    background:
            radial-gradient(circle at top left, rgba(15, 139, 141, .16), transparent 34rem),
            linear-gradient(180deg, #f8fbff 0%, var(--bg) 48%, #eef3f8 100%);
    color: var(--ink);
    line-height: 1.65;
}

@media (prefers-color-scheme: dark) {
    body {
        background:
                radial-gradient(circle at top left, rgba(47, 195, 189, .16), transparent 34rem),
                linear-gradient(180deg, #101827 0%, var(--bg) 52%, #0c1422 100%);
    }
}

a { color: var(--accent-dark); text-decoration-thickness: 1px; text-underline-offset: 3px; }

.page {
    width: min(1120px, calc(100% - 32px));
    margin: 0 auto;
    padding: 34px 0 56px;
}

.topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 28px;
}

.brand {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 800;
    letter-spacing: .02em;
}

.mark {
    width: 42px;
    height: 42px;
    border-radius: 8px;
    display: grid;
    place-items: center;
    background: var(--accent);
    color: white;
    font-weight: 900;
    box-shadow: 0 10px 24px rgba(15, 139, 141, .28);
}

nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    justify-content: flex-end;
    font-size: 14px;
}

nav a {
    padding: 9px 12px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: rgba(255, 255, 255, .72);
    color: var(--ink);
    text-decoration: none;
}

@media (prefers-color-scheme: dark) {
    nav a {
        background: rgba(24, 34, 53, .78);
    }
}

.hero {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: clamp(28px, 5vw, 58px);
    box-shadow: var(--shadow);
    position: relative;
    overflow: hidden;
}

.hero::after {
    content: "";
    position: absolute;
    right: 0;
    top: 0;
    width: 40%;
    height: 100%;
    background: linear-gradient(135deg, transparent, rgba(15, 139, 141, .10));
    pointer-events: none;
}

.eyebrow {
    color: var(--accent-dark);
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: .08em;
    font-size: 13px;
    margin: 0 0 12px;
}

h1 {
    font-size: clamp(34px, 6vw, 64px);
    line-height: 1.02;
    letter-spacing: 0;
    margin: 0;
    max-width: 820px;
    position: relative;
    z-index: 1;
}

.subtitle {
    margin: 20px 0 0;
    max-width: 790px;
    color: var(--muted);
    font-size: 18px;
    position: relative;
    z-index: 1;
}

.meta {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-top: 22px;
    position: relative;
    z-index: 1;
}

.meta div {
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 14px;
    background: #fbfdff;
    min-width: 0;
}

@media (prefers-color-scheme: dark) {
    .meta div {
        background: #142033;
    }
}

.meta b {
    display: block;
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--muted);
    margin-bottom: 4px;
}

main {
    display: grid;
    grid-template-columns: 280px minmax(0, 1fr);
    gap: 24px;
    margin-top: 24px;
    align-items: start;
}

.toc {
    position: sticky;
    top: 18px;
    background: rgba(255, 255, 255, .86);
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: 18px;
    backdrop-filter: blur(8px);
}

@media (prefers-color-scheme: dark) {
    .toc {
        background: rgba(24, 34, 53, .86);
    }
}

.toc h2 {
    font-size: 14px;
    text-transform: uppercase;
    letter-spacing: .08em;
    color: var(--muted);
    margin: 0 0 12px;
}

.toc a {
    display: block;
    color: var(--ink);
    text-decoration: none;
    padding: 8px 0;
    border-top: 1px solid var(--line);
    font-size: 14px;
}

.doc {
    background: var(--paper);
    border: 1px solid var(--line);
    border-radius: 8px;
    padding: clamp(22px, 4vw, 44px);
    box-shadow: 0 12px 34px rgba(30, 47, 76, .08);
}

section + section { margin-top: 34px; padding-top: 30px; border-top: 1px solid var(--line); }

h2 {
    font-size: clamp(22px, 3vw, 31px);
    line-height: 1.2;
    letter-spacing: 0;
    margin: 0 0 14px;
}

h3 {
    font-size: 18px;
    margin: 22px 0 8px;
}

p { margin: 0 0 14px; }
ul, ol { padding-left: 22px; margin: 10px 0 16px; }
li + li { margin-top: 8px; }

.notice {
    background: var(--soft);
    border: 1px solid #c6e8e8;
    border-radius: 8px;
    padding: 16px 18px;
    margin: 18px 0;
}

.warning {
    background: var(--warn);
    border: 1px solid #f2dcaa;
    border-radius: 8px;
    padding: 16px 18px;
    margin: 18px 0;
}

.danger {
    background: #fff0f0;
    border: 1px solid #f0b6b6;
    border-radius: 8px;
    color: #7d1f1f;
    padding: 16px 18px;
    margin: 18px 0;
}

@media (prefers-color-scheme: dark) {
    .notice {
        border-color: #245d63;
    }

    .warning {
        border-color: #5d4821;
    }

    .danger {
        background: #351a1d;
        border-color: #704047;
        color: #ffd8d8;
    }
}

.footer {
    color: var(--muted);
    font-size: 14px;
    margin-top: 24px;
    text-align: center;
}

@media (max-width: 840px) {
    .topbar { align-items: flex-start; flex-direction: column; }
    nav { justify-content: flex-start; }
    main { grid-template-columns: 1fr; }
    .toc { position: static; }
    .meta { grid-template-columns: 1fr; }
    .hero::after { width: 100%; opacity: .7; }
}