:root {
    --bg: #f8fafc;
    --surface: #ffffff;
    --text: #1e293b;
    --muted: #64748b;
    --border: #e2e8f0;
    --brand: #4f46e5;
    --brand-dark: #4338ca;
    --code-bg: #0f172a;
    --code-text: #e2e8f0;
    --note: #eef2ff;
    --warn: #fef3c7;
    --warn-border: #f59e0b;
    --radius: 12px;
    --max: 980px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.65;
    font-size: 16px;
}

a { color: var(--brand); text-decoration: none; }
a:hover { text-decoration: underline; }

.layout { display: flex; align-items: flex-start; max-width: 1280px; margin: 0 auto; }

/* Sidebar */
.toc {
    position: sticky;
    top: 0;
    align-self: flex-start;
    width: 260px;
    flex: 0 0 260px;
    height: 100vh;
    overflow-y: auto;
    padding: 28px 18px;
    border-right: 1px solid var(--border);
    background: var(--surface);
}
.toc h2 { font-size: 13px; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin: 0 0 14px; }
.toc ol { list-style: none; margin: 0; padding: 0; counter-reset: item; }
.toc li { margin: 2px 0; }
.toc a { display: block; padding: 5px 10px; border-radius: 8px; font-size: 14px; color: #334155; }
.toc a:hover { background: var(--note); text-decoration: none; }
.toc .sub { padding-left: 22px; font-size: 13px; color: var(--muted); }

/* Content */
main { flex: 1; min-width: 0; padding: 40px 44px 96px; }

.hero { border-bottom: 1px solid var(--border); padding-bottom: 24px; margin-bottom: 32px; }
.hero .eyebrow { color: var(--brand); font-weight: 600; font-size: 13px; letter-spacing: .08em; text-transform: uppercase; }
.hero h1 { font-size: 34px; margin: 6px 0 8px; line-height: 1.2; }
.hero p { color: var(--muted); margin: 0; }

section { scroll-margin-top: 20px; margin: 40px 0; }
h2 { font-size: 24px; margin: 0 0 8px; padding-bottom: 8px; border-bottom: 1px solid var(--border); }
h3 { font-size: 18px; margin: 26px 0 6px; }
h4 { font-size: 15px; margin: 20px 0 4px; color: #334155; }
p { margin: 8px 0; }

ul, ol { padding-left: 22px; }
li { margin: 4px 0; }

code {
    font-family: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
    background: #eef2f7;
    padding: 2px 6px;
    border-radius: 6px;
    font-size: .88em;
    color: #0f172a;
}
pre {
    background: var(--code-bg);
    color: var(--code-text);
    padding: 16px 18px;
    border-radius: var(--radius);
    overflow-x: auto;
    font-size: 13.5px;
    line-height: 1.6;
    margin: 12px 0;
}
pre code { background: none; color: inherit; padding: 0; font-size: inherit; }

table { width: 100%; border-collapse: collapse; margin: 14px 0; font-size: 14.5px; background: var(--surface); border-radius: var(--radius); overflow: hidden; box-shadow: 0 1px 2px rgba(15,23,42,.05); }
th, td { text-align: left; padding: 10px 14px; border-bottom: 1px solid var(--border); vertical-align: top; }
th { background: #f1f5f9; font-size: 12.5px; text-transform: uppercase; letter-spacing: .04em; color: #475569; }
tr:last-child td { border-bottom: none; }

.note, .warn, .tip {
    border-radius: var(--radius);
    padding: 14px 16px;
    margin: 14px 0;
    border-left: 4px solid var(--brand);
    background: var(--note);
    font-size: 14.5px;
}
.warn { border-left-color: var(--warn-border); background: var(--warn); }
.tip { border-left-color: #10b981; background: #ecfdf5; }
.note strong, .warn strong, .tip strong { display: block; margin-bottom: 2px; }

.badges { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
.badge { font-size: 12.5px; background: #eef2ff; color: var(--brand-dark); border: 1px solid #c7d2fe; padding: 3px 10px; border-radius: 999px; }

.grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 14px; margin: 16px 0; }
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; }
.card h4 { margin-top: 0; }
.card p { color: var(--muted); font-size: 14px; margin: 4px 0 0; }

kbd { background: #fff; border: 1px solid var(--border); border-bottom-width: 2px; border-radius: 6px; padding: 1px 6px; font-size: 12.5px; font-family: inherit; }

.footer { margin-top: 60px; padding-top: 20px; border-top: 1px solid var(--border); color: var(--muted); font-size: 13px; }

.back { display: inline-block; margin-bottom: 8px; font-size: 13px; }

@media (max-width: 900px) {
    .layout { display: block; }
    .toc { position: static; width: auto; height: auto; flex: none; border-right: none; border-bottom: 1px solid var(--border); }
    main { padding: 28px 20px 72px; }
    .hero h1 { font-size: 27px; }
}

@media print {
    .toc { display: none; }
    main { padding: 0; }
    pre { white-space: pre-wrap; }
    a { color: var(--text); }
}