/* ===== Токены ===== */
:root {
  --font: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "Cascadia Code", "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --bg: #f7f8fb;
  --bg-elev: #ffffff;
  --bg-soft: #f0f2f7;
  --bg-code: #f6f8fa;
  --border: #e3e7ef;
  --border-strong: #cfd6e3;
  --text: #121826;
  --text-2: #3a4556;
  --muted: #667085;
  --accent: #512bd4;
  --accent-2: #3b6fd8;
  --accent-soft: #efeafd;
  --good: #15803d; --good-bg: #ecfdf3; --good-bd: #a7e3bf;
  --warn: #b45309; --warn-bg: #fff8eb; --warn-bd: #f5d49a;
  --bad: #b42318; --bad-bg: #fef1f0; --bad-bd: #f5b8b2;
  --info: #1d4ed8; --info-bg: #eef4ff; --info-bd: #b8cdfa;
  --tldr-bg: #f3efff; --tldr-bd: #c8b8f7;
  --shadow: 0 1px 2px rgba(16, 24, 40, .05), 0 1px 3px rgba(16, 24, 40, .06);
  --shadow-lg: 0 8px 24px rgba(16, 24, 40, .10);
  --radius: 12px;
  --topbar-h: 60px;
  /* подсветка кода */
  --hl-kw: #cf222e; --hl-type: #8250df; --hl-str: #0a3069; --hl-num: #0550ae; --hl-com: #6e7781;
  --hl-fn: #6639ba; --hl-attr: #953800; --hl-lit: #0550ae; --hl-meta: #116329;
  color-scheme: light;
}
:root[data-theme="dark"] {
  --bg: #0e1117;
  --bg-elev: #161b24;
  --bg-soft: #1c2230;
  --bg-code: #11161f;
  --border: #262e3d;
  --border-strong: #354055;
  --text: #e6eaf2;
  --text-2: #c2cad8;
  --muted: #8a94a8;
  --accent: #9b85ff;
  --accent-2: #6b98f0;
  --accent-soft: #231d3d;
  --good: #4ade80; --good-bg: #0f2419; --good-bd: #1f5a3a;
  --warn: #fbbf24; --warn-bg: #2a200b; --warn-bd: #5c4513;
  --bad: #f87171; --bad-bg: #2c1414; --bad-bd: #6b2626;
  --info: #7aa7ff; --info-bg: #111c33; --info-bd: #27406e;
  --tldr-bg: #1b1733; --tldr-bd: #3f3480;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-lg: 0 10px 30px rgba(0, 0, 0, .45);
  --hl-kw: #ff7b72; --hl-type: #d2a8ff; --hl-str: #a5d6ff; --hl-num: #79c0ff; --hl-com: #8b949e;
  --hl-fn: #d2a8ff; --hl-attr: #ffa657; --hl-lit: #79c0ff; --hl-meta: #7ee787;
  color-scheme: dark;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) { --bg: #0e1117; --bg-elev: #161b24; --text: #e6eaf2; --border: #262e3d; }
}

/* ===== База ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-padding-top: calc(var(--topbar-h) + 16px); -webkit-text-size-adjust: 100%; }
body { margin: 0; font-family: var(--font); font-size: 16px; line-height: 1.65; background: var(--bg); color: var(--text); }
a { color: var(--accent-2); text-decoration: none; }
a:hover { text-decoration: underline; }
img, svg { max-width: 100%; }
.icon { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; flex-shrink: 0; }
.icon.sm { width: 16px; height: 16px; }
.skip { position: absolute; left: -9999px; }
.skip:focus { left: 12px; top: 12px; z-index: 100; background: var(--bg-elev); padding: 8px 12px; border-radius: 8px; }
:focus-visible { outline: 2px solid var(--accent-2); outline-offset: 2px; border-radius: 4px; }
kbd { font-family: var(--mono); font-size: 11px; padding: 1px 6px; border: 1px solid currentColor; border-radius: 4px; opacity: .6; margin-left: 6px; }
.bar { height: 6px; border-radius: 99px; background: var(--bg-soft); overflow: hidden; flex: 1; min-width: 40px; }
.bar i { display: block; height: 100%; width: 0; background: var(--cat, var(--accent)); border-radius: 99px; transition: width .4s ease; }

/* ===== Шапка ===== */
.topbar { position: sticky; top: 0; z-index: 50; height: var(--topbar-h); background: color-mix(in srgb, var(--bg-elev) 88%, transparent); backdrop-filter: saturate(160%) blur(10px); border-bottom: 1px solid var(--border); }
.topbar-in { max-width: 1440px; margin: 0 auto; height: 100%; display: flex; align-items: center; gap: 16px; padding: 0 20px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--text); font-weight: 700; white-space: nowrap; }
.brand:hover { text-decoration: none; }
.logo-mark { width: 32px; height: 32px; color: #512bd4; }
.search { position: relative; flex: 1; max-width: 520px; margin-left: auto; display: flex; align-items: center; }
.search > .icon { position: absolute; left: 12px; color: var(--muted); pointer-events: none; }
.search input { width: 100%; height: 40px; padding: 0 14px 0 40px; border-radius: 10px; border: 1px solid var(--border); background: var(--bg-soft); color: var(--text); font: inherit; font-size: 15px; outline: none; }
.search input:focus { border-color: var(--accent-2); background: var(--bg-elev); box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent-2) 20%, transparent); }
.search-results { position: absolute; top: calc(100% + 6px); left: 0; right: 0; max-height: min(70vh, 560px); overflow: auto; background: var(--bg-elev); border: 1px solid var(--border); border-radius: 12px; box-shadow: var(--shadow-lg); padding: 6px; }
.sr-item { display: block; padding: 10px 12px; border-radius: 8px; color: var(--text); }
.sr-item:hover, .sr-item.sel { background: var(--bg-soft); text-decoration: none; }
.sr-cat { font-size: 12px; color: var(--muted); display: flex; align-items: center; gap: 6px; }
.sr-cat::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--c); }
.sr-t { font-weight: 600; font-size: 14.5px; line-height: 1.4; }
.sr-s { font-size: 13px; color: var(--muted); display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.sr-empty { padding: 14px; color: var(--muted); font-size: 14px; }
mark { background: color-mix(in srgb, #facc15 45%, transparent); color: inherit; border-radius: 3px; padding: 0 1px; }
.top-actions { display: flex; gap: 6px; }
.btn-ghost { display: inline-flex; align-items: center; gap: 8px; height: 40px; padding: 0 12px; border-radius: 10px; border: 1px solid transparent; background: none; color: var(--text-2); font: inherit; font-size: 14.5px; font-weight: 500; cursor: pointer; }
.btn-ghost:hover { background: var(--bg-soft); text-decoration: none; }
.btn-ghost.icon-only { width: 40px; padding: 0; justify-content: center; }
#theme-toggle .icon:nth-child(2) { display: none; }
[data-theme="dark"] #theme-toggle .icon:nth-child(1) { display: none; }
[data-theme="dark"] #theme-toggle .icon:nth-child(2) { display: block; }

/* ===== Кнопки ===== */
.btn-primary, .btn-secondary { display: inline-flex; align-items: center; gap: 8px; min-height: 44px; padding: 0 18px; border-radius: 10px; font: inherit; font-weight: 600; font-size: 15px; cursor: pointer; border: 1px solid transparent; }
.btn-primary { background: var(--accent); color: #fff; }
[data-theme="dark"] .btn-primary { color: #120b2e; }
.btn-primary:hover { filter: brightness(1.08); text-decoration: none; }
.btn-secondary { background: var(--bg-elev); color: var(--text); border-color: var(--border-strong); }
.btn-secondary:hover { background: var(--bg-soft); text-decoration: none; }
.btn-secondary.good { border-color: var(--good-bd); color: var(--good); }
.btn-secondary.bad { border-color: var(--bad-bd); color: var(--bad); }
.btn-link { background: none; border: 0; color: var(--accent-2); font: inherit; font-weight: 500; cursor: pointer; padding: 8px 4px; }

/* ===== Общие страницы ===== */
.page { max-width: 1120px; margin: 0 auto; padding: 28px 20px 64px; }
.crumbs { display: flex; flex-wrap: wrap; gap: 8px; font-size: 14px; color: var(--muted); margin-bottom: 18px; }
.crumbs a { color: var(--muted); }
.crumbs a:hover { color: var(--accent-2); }
.lead { font-size: 18px; color: var(--text-2); margin: 8px 0 0; }
h1, h2, h3, h4 { line-height: 1.25; letter-spacing: -.01em; }
.chip { display: inline-flex; align-items: center; gap: 5px; font-size: 12.5px; font-weight: 600; padding: 3px 10px; border-radius: 99px; background: var(--bg-soft); color: var(--text-2); white-space: nowrap; }
.chip .icon { width: 14px; height: 14px; }
.lv-junior { background: var(--good-bg); color: var(--good); --lv: var(--good); }
.lv-middle { background: var(--info-bg); color: var(--info); --lv: var(--info); }
.lv-senior { background: var(--accent-soft); color: var(--accent); --lv: var(--accent); }
.done-mark { display: none; color: var(--good); }
.is-done .done-mark { display: inline-flex; }

/* ===== Главная ===== */
.hero { display: grid; grid-template-columns: 1.5fr 1fr; gap: 40px; align-items: center; padding: 32px 0 40px; }
.eyebrow { display: inline-block; font-size: 13px; font-weight: 600; letter-spacing: .04em; text-transform: uppercase; color: var(--accent); background: var(--accent-soft); padding: 4px 12px; border-radius: 99px; }
.hero h1 { font-size: clamp(32px, 5vw, 52px); margin: 16px 0 8px; letter-spacing: -.025em; }
.grad { background: linear-gradient(90deg, #512bd4, #3b6fd8 60%, #0ea5a4); -webkit-background-clip: text; background-clip: text; color: transparent; }
[data-theme="dark"] .grad { background-image: linear-gradient(90deg, #a78bfa, #7aa7ff 60%, #2dd4bf); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 24px; align-items: center; }
.hero-stats { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
.stat { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.stat b { display: block; font-size: 30px; line-height: 1.1; color: var(--text); font-variant-numeric: tabular-nums; }
.stat span { font-size: 13px; color: var(--muted); }
.progress-stat .bar { margin-top: 10px; }
.how { margin: 8px 0 44px; }
.how h2, .section-head h2 { font-size: 24px; margin: 0 0 16px; }
.how-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px; }
.how-item { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; }
.how-item b { display: block; margin: 8px 0 4px; }
.how-item p { margin: 0; font-size: 14px; color: var(--muted); line-height: 1.5; }
.how-n { display: inline-grid; place-items: center; width: 28px; height: 28px; border-radius: 8px; background: var(--accent-soft); color: var(--accent); font-weight: 700; font-size: 14px; }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; }
.cat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 16px; }
.cat-card { display: flex; flex-direction: column; background: var(--bg-elev); border: 1px solid var(--border); border-radius: 14px; padding: 20px; color: var(--text); box-shadow: var(--shadow); transition: transform .15s ease, box-shadow .15s ease, border-color .15s ease; position: relative; overflow: hidden; }
.cat-card::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 3px; background: var(--cat); }
.cat-card:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); border-color: color-mix(in srgb, var(--cat) 40%, var(--border)); text-decoration: none; }
.cat-card-top { display: flex; justify-content: space-between; align-items: center; }
.cat-icon { display: inline-grid; place-items: center; width: 44px; height: 44px; border-radius: 12px; background: color-mix(in srgb, var(--cat) 14%, transparent); color: var(--cat); }
[data-theme="dark"] .cat-icon { color: color-mix(in srgb, var(--cat) 60%, white); background: color-mix(in srgb, var(--cat) 26%, transparent); }
.cat-icon .icon { width: 24px; height: 24px; }
.cat-n { font-family: var(--mono); font-size: 13px; color: var(--muted); }
.cat-card h3 { font-size: 18px; margin: 14px 0 6px; }
.cat-card p { margin: 0 0 16px; font-size: 14px; color: var(--muted); line-height: 1.5; flex: 1; }
.cat-card-foot { display: flex; align-items: center; gap: 10px; font-size: 13px; color: var(--muted); }

/* ===== Раздел ===== */
.cat-hero { display: flex; gap: 20px; align-items: flex-start; margin-bottom: 24px; }
.cat-hero .cat-icon { width: 64px; height: 64px; border-radius: 16px; }
.cat-hero .cat-icon .icon { width: 32px; height: 32px; }
.cat-hero > div:last-child { flex: 1; }
.cat-hero h1 { font-size: clamp(28px, 4vw, 40px); margin: 0; }
.cat-progress, .side-progress { display: flex; align-items: center; gap: 12px; margin-top: 14px; font-size: 13px; color: var(--muted); max-width: 420px; }
.cat-intro { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 4px 24px; margin-bottom: 24px; }
.q-list { list-style: none; padding: 0; margin: 0 0 32px; display: grid; gap: 10px; }
.q-row { display: flex; align-items: flex-start; gap: 16px; padding: 16px 18px; background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); color: var(--text); transition: border-color .15s ease, box-shadow .15s ease; }
.q-row:hover { border-color: color-mix(in srgb, var(--cat) 50%, var(--border)); box-shadow: var(--shadow); text-decoration: none; }
.q-num { flex-shrink: 0; display: inline-grid; place-items: center; width: 32px; height: 32px; border-radius: 9px; background: var(--bg-soft); font-weight: 700; font-size: 14px; color: var(--text-2); font-variant-numeric: tabular-nums; }
.q-row.is-done .q-num { background: var(--good-bg); color: var(--good); }
.q-main { flex: 1; min-width: 0; overflow-wrap: anywhere; }
.q-title { display: block; font-weight: 600; font-size: 16.5px; line-height: 1.4; }
.q-sub { display: block; font-size: 14px; color: var(--muted); margin-top: 4px; line-height: 1.5; }
.q-side { display: flex; flex-direction: column; align-items: flex-end; gap: 6px; flex-shrink: 0; }
.q-min { font-size: 12.5px; color: var(--muted); }

/* ===== Страница вопроса ===== */
.doc-layout { max-width: 1440px; margin: 0 auto; display: grid; grid-template-columns: 290px minmax(0, 1fr) 230px; gap: 40px; padding: 0 20px; }
.sidebar { position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h)); overflow-y: auto; padding: 24px 0 40px; scrollbar-width: thin; }
.side-cat { display: flex; align-items: center; gap: 10px; font-weight: 700; color: var(--text); padding: 4px 8px; }
.side-cat .icon { color: var(--cat); }
.side-progress { margin: 10px 8px 14px; }
.side-list { list-style: none; margin: 0; padding: 0; }
.side-list a { display: flex; gap: 10px; align-items: flex-start; padding: 7px 8px; border-radius: 8px; color: var(--text-2); font-size: 14px; line-height: 1.4; }
.side-list a:hover { background: var(--bg-soft); text-decoration: none; }
.side-list a.active { background: color-mix(in srgb, var(--cat) 12%, transparent); color: var(--text); font-weight: 600; }
.side-list .num { flex-shrink: 0; width: 22px; font-size: 12.5px; color: var(--muted); padding-top: 1px; font-variant-numeric: tabular-nums; }
.side-list .t { flex: 1; }
.side-list .done-mark .icon { width: 16px; height: 16px; }
.side-other { margin-top: 18px; border-top: 1px solid var(--border); padding-top: 12px; }
.side-other summary { cursor: pointer; font-size: 14px; font-weight: 600; color: var(--muted); padding: 4px 8px; }
.side-other ul { list-style: none; padding: 0; margin: 6px 0 0; }
.side-other a { display: flex; align-items: center; gap: 8px; padding: 6px 8px; border-radius: 8px; font-size: 14px; color: var(--text-2); }
.side-other a .icon { color: var(--cat); }
.side-other a:hover { background: var(--bg-soft); text-decoration: none; }
.side-toggle { display: none; }
.article-wrap { padding: 24px 0 64px; min-width: 0; }
.article { max-width: 820px; }
.article-head { margin-bottom: 8px; }
.article-head .meta { display: flex; flex-wrap: wrap; gap: 8px; }
.article-head h1 { font-size: clamp(26px, 3.4vw, 36px); margin: 14px 0 16px; letter-spacing: -.02em; overflow-wrap: anywhere; }
.learn-btn { display: inline-flex; align-items: center; gap: 8px; padding: 7px 14px; border-radius: 99px; border: 1px solid var(--border-strong); background: var(--bg-elev); color: var(--text-2); font: inherit; font-size: 14px; font-weight: 600; cursor: pointer; }
.learn-btn .icon { width: 16px; height: 16px; }
.learn-btn:hover { border-color: var(--good-bd); color: var(--good); }
.learn-btn.on { background: var(--good-bg); border-color: var(--good-bd); color: var(--good); }
.learn-btn.big { padding: 12px 22px; font-size: 15px; }
.article-end { margin: 40px 0 24px; padding-top: 24px; border-top: 1px solid var(--border); display: flex; justify-content: center; }
.toc { position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h)); overflow-y: auto; padding: 28px 0; }
.toc-title { font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); margin-bottom: 10px; }
.toc ol { list-style: none; margin: 0; padding: 0; border-left: 1px solid var(--border); }
.toc a { display: block; padding: 5px 0 5px 14px; margin-left: -1px; border-left: 2px solid transparent; font-size: 13.5px; color: var(--muted); line-height: 1.4; }
.toc a:hover { color: var(--text); text-decoration: none; }
.toc a.active { color: var(--accent-2); border-left-color: var(--accent-2); font-weight: 600; }
.prev-next { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-top: 16px; }
.pn { display: flex; flex-direction: column; gap: 4px; padding: 16px 18px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elev); color: var(--text); }
.pn:hover { border-color: var(--accent-2); text-decoration: none; }
.pn.next { text-align: right; align-items: flex-end; }
.pn-dir { display: inline-flex; align-items: center; gap: 4px; font-size: 13px; color: var(--muted); }
.pn-dir .icon { width: 16px; height: 16px; }
.pn-cat { font-size: 12px; color: var(--muted); }
.pn-t { font-weight: 600; font-size: 15px; line-height: 1.4; }

/* ===== Типографика статьи ===== */
.prose { font-size: 16.5px; color: var(--text); overflow-wrap: break-word; }
.prose > :first-child { margin-top: 0; }
.prose h2 { font-size: 25px; margin: 48px 0 14px; padding-top: 8px; }
.prose h3 { font-size: 19.5px; margin: 32px 0 10px; }
.prose h4 { font-size: 17px; margin: 24px 0 8px; }
.prose h2, .prose h3, .prose h4 { position: relative; }
.prose .anchor { position: absolute; left: -22px; color: var(--muted); opacity: 0; font-weight: 400; padding-right: 6px; }
.prose h2:hover .anchor, .prose h3:hover .anchor { opacity: .6; text-decoration: none; }
.prose p { margin: 12px 0; }
.prose ul, .prose ol { padding-left: 24px; margin: 12px 0; }
.prose li { margin: 6px 0; }
.prose li > p { margin: 4px 0; }
.prose strong { font-weight: 650; }
.prose blockquote { margin: 16px 0; padding: 4px 18px; border-left: 3px solid var(--border-strong); color: var(--text-2); }
.prose hr { border: 0; border-top: 1px solid var(--border); margin: 32px 0; }
.prose :not(pre) > code { font-family: var(--mono); font-size: .88em; background: var(--bg-soft); border: 1px solid var(--border); padding: .1em .38em; border-radius: 6px; overflow-wrap: anywhere; }
.table-wrap { overflow-x: auto; margin: 18px 0; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elev); }
.prose table { width: 100%; border-collapse: collapse; font-size: 14.5px; line-height: 1.5; }
.prose th, .prose td { padding: 10px 14px; text-align: left; vertical-align: top; border-bottom: 1px solid var(--border); }
.prose th { background: var(--bg-soft); font-weight: 650; white-space: nowrap; }
.prose tr:last-child td { border-bottom: 0; }
.prose td:first-child { font-weight: 600; }

/* код */
.code { margin: 18px 0; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; background: var(--bg-code); }
.code-head { display: flex; justify-content: space-between; align-items: center; padding: 6px 8px 6px 14px; font-size: 12.5px; color: var(--muted); border-bottom: 1px solid var(--border); background: var(--bg-soft); font-weight: 600; }
.copy { font: inherit; font-size: 12px; background: none; border: 1px solid var(--border); color: var(--muted); border-radius: 6px; padding: 2px 10px; cursor: pointer; }
.copy:hover { color: var(--text); border-color: var(--border-strong); }
.code pre { margin: 0; padding: 14px 16px; overflow-x: auto; font-family: var(--mono); font-size: 13.8px; line-height: 1.6; tab-size: 4; }
.code code { font-family: inherit; color: var(--text); }
.hljs-keyword, .hljs-built_in, .hljs-selector-tag, .hljs-doctag { color: var(--hl-kw); }
.hljs-type, .hljs-title.class_, .hljs-title.class_.inherited__ { color: var(--hl-type); }
.hljs-string, .hljs-regexp, .hljs-char.escape_ { color: var(--hl-str); }
.hljs-number, .hljs-literal { color: var(--hl-num); }
.hljs-comment, .hljs-quote { color: var(--hl-com); font-style: italic; }
.hljs-title, .hljs-title.function_ { color: var(--hl-fn); }
.hljs-attr, .hljs-attribute, .hljs-variable, .hljs-template-variable, .hljs-property, .hljs-params { color: var(--hl-attr); }
.hljs-meta, .hljs-meta .hljs-keyword, .hljs-section, .hljs-name { color: var(--hl-meta); }
.hljs-symbol, .hljs-bullet, .hljs-link, .hljs-selector-id, .hljs-selector-class { color: var(--hl-lit); }
.hljs-addition { color: var(--good); background: var(--good-bg); }
.hljs-deletion { color: var(--bad); background: var(--bad-bg); }
.hljs-emphasis { font-style: italic; }
.hljs-strong { font-weight: 700; }

/* диаграммы */
.diagram { margin: 22px 0; padding: 18px; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elev); overflow-x: auto; }
.dg { display: block; }
.dg svg { display: block; height: auto; margin: 0 auto; }
.dg-dark { display: none; }
[data-theme="dark"] .dg-light { display: none; }
[data-theme="dark"] .dg-dark { display: block; }
.diagram figcaption { margin-top: 12px; text-align: center; font-size: 13.5px; color: var(--muted); }

/* выноски */
.callout { margin: 20px 0; padding: 14px 18px; border-radius: var(--radius); border: 1px solid; }
.callout-title { font-weight: 700; font-size: 14px; margin-bottom: 4px; display: flex; align-items: center; gap: 8px; }
.callout-title::before { font-size: 16px; }
.callout > :last-child { margin-bottom: 4px; }
.callout ul, .callout ol { margin: 6px 0; }
.tldr { background: var(--tldr-bg); border-color: var(--tldr-bd); padding: 16px 20px; }
.tldr .callout-title { color: var(--accent); text-transform: uppercase; letter-spacing: .04em; font-size: 12.5px; }
.tldr .callout-title::before { content: "⚡"; }
.tip { background: var(--good-bg); border-color: var(--good-bd); }
.tip .callout-title { color: var(--good); }
.tip .callout-title::before { content: "💡"; }
.note { background: var(--info-bg); border-color: var(--info-bd); }
.note .callout-title { color: var(--info); }
.note .callout-title::before { content: "ℹ️"; }
.warning { background: var(--warn-bg); border-color: var(--warn-bd); }
.warning .callout-title { color: var(--warn); }
.warning .callout-title::before { content: "⚠️"; }
.example { background: var(--bg-soft); border-color: var(--border-strong); }
.example .callout-title::before { content: "🛠️"; }
.compare { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 14px; margin: 18px 0; }
.compare > div, .compare > ul { margin: 0; }

/* вопросы на засыпку */
.qa { margin: 10px 0; border: 1px solid var(--border); border-radius: var(--radius); background: var(--bg-elev); }
.qa summary { cursor: pointer; padding: 12px 16px 12px 42px; font-weight: 600; list-style: none; position: relative; }
.qa summary::-webkit-details-marker { display: none; }
.qa summary::before { content: "?"; position: absolute; left: 14px; top: 12px; width: 20px; height: 20px; border-radius: 50%; background: var(--accent-soft); color: var(--accent); font-size: 13px; font-weight: 700; display: grid; place-items: center; line-height: 1; }
.qa[open] summary { border-bottom: 1px solid var(--border); }
.qa[open] summary::before { content: "✓"; background: var(--good-bg); color: var(--good); }
.qa-body { padding: 4px 16px 8px; }

/* ===== Тренажёр ===== */
.trainer { max-width: 860px; }
.page-head h1 { font-size: clamp(28px, 4vw, 40px); margin: 0; }
.tr-filter { margin: 20px 0 12px; background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 10px 16px; }
.tr-filter summary { cursor: pointer; font-weight: 600; }
.tr-cats { display: flex; flex-wrap: wrap; gap: 8px; margin: 12px 0; }
.tr-cat { display: inline-flex; align-items: center; gap: 6px; padding: 5px 12px; border: 1px solid var(--border); border-radius: 99px; font-size: 14px; cursor: pointer; }
.tr-cat input { accent-color: var(--cat, var(--accent)); }
.only-new { margin-bottom: 8px; }
.tr-stats { display: flex; gap: 20px; font-size: 14px; color: var(--muted); margin-bottom: 12px; }
.card-box { background: var(--bg-elev); border: 1px solid var(--border); border-radius: 16px; padding: 28px; box-shadow: var(--shadow); min-height: 260px; }
.card-cat { font-size: 13px; color: var(--muted); display: flex; gap: 8px; align-items: center; }
.card-q { font-size: 24px; margin: 10px 0 16px; }
.card-a { border-top: 1px solid var(--border); padding-top: 12px; }
.card-actions { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin-top: 20px; }

/* ===== Подвал ===== */
.site-footer { border-top: 1px solid var(--border); background: var(--bg-elev); }
.footer-in { max-width: 1440px; margin: 0 auto; padding: 20px; display: flex; flex-wrap: wrap; gap: 12px; justify-content: space-between; font-size: 14px; color: var(--muted); }

/* ===== Адаптив ===== */
@media (max-width: 1240px) {
  .doc-layout { grid-template-columns: 270px minmax(0, 1fr); }
  .toc { display: none; }
}
@media (max-width: 960px) {
  .hero { grid-template-columns: 1fr; gap: 24px; padding-top: 12px; }
  .how-grid { grid-template-columns: 1fr 1fr; }
  .doc-layout { grid-template-columns: minmax(0, 1fr); gap: 0; }
  .sidebar { position: fixed; z-index: 60; top: var(--topbar-h); left: 0; bottom: 0; height: auto; width: min(340px, 88vw); background: var(--bg-elev); border-right: 1px solid var(--border); padding: 16px 12px 40px; transform: translateX(-105%); transition: transform .2s ease; box-shadow: var(--shadow-lg); }
  .sidebar.open { transform: none; }
  .side-toggle { display: inline-flex; align-items: center; gap: 8px; margin-bottom: 14px; padding: 8px 14px; border: 1px solid var(--border); border-radius: 10px; background: var(--bg-elev); color: var(--text-2); font: inherit; font-size: 14px; font-weight: 600; cursor: pointer; }
  .prose .anchor { display: none; }
}
@media (max-width: 640px) {
  :root { --topbar-h: 56px; }
  .topbar-in { gap: 8px; padding: 0 12px; }
  .brand span, .hide-sm { display: none; }
  .search { margin-left: 0; }
  .page, .doc-layout { padding-left: 16px; padding-right: 16px; }
  .how-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: 1fr 1fr; }
  .q-row { gap: 12px; padding: 14px; flex-wrap: wrap; }
  .q-side { flex-direction: row; align-items: center; width: 100%; padding-left: 44px; }
  .prose { font-size: 16px; }
  .prose h2 { font-size: 22px; }
  .code pre { font-size: 13px; }
  .diagram { padding: 12px; }
  .prev-next { grid-template-columns: 1fr; }
  .pn.next { text-align: left; align-items: flex-start; }
  .cat-hero { flex-direction: column; gap: 12px; }
  .card-box { padding: 20px; }
  .card-q { font-size: 20px; }
}
@media print {
  .topbar, .sidebar, .toc, .prev-next, .learn-btn, .site-footer, .side-toggle, .copy { display: none !important; }
  .doc-layout { display: block; }
  .qa { break-inside: avoid; }
  .qa:not([open]) .qa-body { display: block; }
}

/* ---------- уровни: фильтр, треки, страницы треков ---------- */
.lv-filter { display: flex; flex-wrap: wrap; gap: 8px; margin: 8px 0 16px; }
.lv-btn { font: inherit; font-size: 14px; font-weight: 600; padding: 6px 14px; border-radius: 99px; border: 1px solid var(--border); background: var(--bg-elev); color: var(--text-2); cursor: pointer; }
.lv-btn b { font-weight: 700; opacity: .7; margin-left: 2px; }
.lv-btn.on { border-color: var(--lv, var(--accent)); box-shadow: inset 0 0 0 1px var(--lv, var(--accent)); color: var(--lv, var(--accent)); }
.lv-btn:not(.on) { background: var(--bg-elev); }
.q-list > li[hidden] { display: none; }
.cat-lv { display: flex; flex-wrap: wrap; gap: 6px; margin: 0 0 12px; }
.cat-lv .chip { font-size: 11.5px; padding: 2px 8px; }
.tracks { display: grid; grid-template-columns: 1fr auto 1fr auto 1fr; align-items: stretch; gap: 10px; }
.track { display: flex; flex-direction: column; padding: 20px; border-radius: var(--radius); border: 1px solid var(--border); background: var(--bg-elev); color: var(--text); border-top: 4px solid var(--lv); transition: box-shadow .15s ease, border-color .15s ease; }
.track:hover { text-decoration: none; box-shadow: var(--shadow); border-color: color-mix(in srgb, var(--lv) 45%, var(--border)); border-top-color: var(--lv); }
.track-step { font-size: 12px; font-weight: 700; text-transform: uppercase; letter-spacing: .06em; color: var(--lv); }
.track h3 { margin: 6px 0 8px; font-size: 24px; }
.track p { margin: 0 0 16px; color: var(--text-2); font-size: 14.5px; flex: 1; }
.track-foot { display: flex; align-items: center; gap: 10px; font-size: 13px; color: var(--muted); }
.track-foot .bar { flex: 1; }
.track .bar i { background: var(--lv); }
.track-arrow { align-self: center; color: var(--muted); font-size: 22px; }
.lv-group { margin: 32px 0 0; }
.lv-group h2 { display: flex; align-items: center; gap: 10px; font-size: 20px; margin: 0 0 12px; }
.lv-group h2 a { display: inline-flex; align-items: center; gap: 8px; color: var(--text); }
.lv-group h2 .icon { color: var(--cat); }
.lv-group-n { font-size: 13px; font-weight: 600; color: var(--muted); background: var(--bg-soft); border-radius: 99px; padding: 2px 9px; }
.level-page .page-head .chip { margin-bottom: 12px; }
.level-page .page-head h1 { margin-bottom: 10px; }
.lv-others { display: flex; flex-wrap: wrap; gap: 10px; margin: 40px 0 0; }
.tr-levels { display: flex; flex-wrap: wrap; gap: 8px; margin: 20px 0 0; }
.tr-levels .tr-cat { padding: 6px 10px; }
@media (max-width: 900px) {
  .tracks { grid-template-columns: 1fr; }
  .track-arrow { transform: rotate(90deg); justify-self: center; }
}
.tracks-sec { margin-bottom: 48px; }