:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --border: #e2e5ea;
  --text: #1c2024;
  --muted: #60646c;
  --accent: #3b5bdb;
  --accent-soft: #e8edff;
  --good: #2b8a3e;
  --good-soft: #e6f4ea;
  --warn: #b35c00;
  --warn-soft: #fff1e0;
  --bad: #c92a2a;
  --bad-soft: #fdecec;
  --code-bg: #f3f4f6;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .08);
  --radius: 10px;
  --mono: ui-monospace, SFMono-Regular, "JetBrains Mono", Menlo, Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #111317; --surface: #1a1d23; --surface-2: #22262e; --border: #2e333c;
    --text: #e6e8eb; --muted: #9ba1ab; --accent: #7c95ff; --accent-soft: #232b48;
    --good: #5cc275; --good-soft: #1b2e21; --warn: #f0a050; --warn-soft: #33271a;
    --bad: #f07070; --bad-soft: #3a1f22; --code-bg: #15181d;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4);
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #111317; --surface: #1a1d23; --surface-2: #22262e; --border: #2e333c;
  --text: #e6e8eb; --muted: #9ba1ab; --accent: #7c95ff; --accent-soft: #232b48;
  --good: #5cc275; --good-soft: #1b2e21; --warn: #f0a050; --warn-soft: #33271a;
  --bad: #f07070; --bad-soft: #3a1f22; --code-bg: #15181d;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4);
  color-scheme: dark;
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--bg); color: var(--text);
  font: 15px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: 1040px; margin: 0 auto; padding: 0 16px; }

/* Top bar */
.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; gap: 16px; flex-wrap: wrap;
  padding: 10px 16px; background: var(--surface); border-bottom: 1px solid var(--border);
}
.brand { font-weight: 700; color: var(--text); white-space: nowrap; }
.brand:hover { text-decoration: none; }
.nav { display: flex; gap: 4px; flex: 1; overflow-x: auto; }
.nav a { padding: 6px 10px; border-radius: 8px; color: var(--muted); white-space: nowrap; }
.nav a:hover { background: var(--surface-2); text-decoration: none; }
.nav a.active { color: var(--accent); background: var(--accent-soft); font-weight: 600; }
.icon-btn { border: 1px solid var(--border); background: var(--surface); color: var(--text); border-radius: 8px; width: 34px; height: 34px; cursor: pointer; font-size: 16px; }

main { padding-top: 24px; padding-bottom: 32px; min-height: 70vh; }
h1 { font-size: 26px; margin: 0 0 6px; }
h2 { font-size: 20px; margin: 28px 0 12px; }
.lead { color: var(--muted); margin: 0 0 20px; }

/* Cards & grid */
.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); padding: 16px; }
.grid { display: grid; gap: 12px; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); }
.stats { display: grid; gap: 12px; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); margin-bottom: 20px; }
.stat .num { font-size: 28px; font-weight: 700; font-variant-numeric: tabular-nums; }
.stat .label { color: var(--muted); font-size: 13px; }
.topic-card { display: flex; flex-direction: column; gap: 8px; color: var(--text); transition: border-color .15s; }
.topic-card:hover { border-color: var(--accent); text-decoration: none; }
.topic-card .title { font-weight: 600; display: flex; gap: 8px; align-items: center; }
.topic-card .summary { color: var(--muted); font-size: 13px; flex: 1; }
.topic-card .meta { display: flex; justify-content: space-between; font-size: 12px; color: var(--muted); }

.progress { height: 6px; background: var(--surface-2); border-radius: 99px; overflow: hidden; display: flex; }
.progress span { display: block; height: 100%; }
.progress .p-known { background: var(--good); }
.progress .p-learning { background: var(--warn); }

.actions { display: flex; gap: 10px; flex-wrap: wrap; margin: 16px 0; }
.btn {
  display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--border);
  background: var(--surface); color: var(--text); padding: 8px 14px; border-radius: 8px;
  font: inherit; font-weight: 500; cursor: pointer; text-decoration: none;
}
.btn:hover { border-color: var(--accent); text-decoration: none; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }
.btn.good { background: var(--good-soft); border-color: var(--good); color: var(--good); }
.btn.warn { background: var(--warn-soft); border-color: var(--warn); color: var(--warn); }
.btn.bad { background: var(--bad-soft); border-color: var(--bad); color: var(--bad); }
.btn:disabled { opacity: .5; cursor: default; }
.btn kbd { font-size: 11px; opacity: .7; }
.link-btn { background: none; border: none; color: var(--muted); cursor: pointer; font: inherit; padding: 0; }
.link-btn:hover { color: var(--accent); }
.link-btn.danger:hover { color: var(--bad); }

/* Badges */
.badges { display: flex; gap: 6px; flex-wrap: wrap; }
.badge { font-size: 12px; padding: 1px 8px; border-radius: 99px; background: var(--surface-2); color: var(--muted); white-space: nowrap; }
.badge.level-senior { background: var(--accent-soft); color: var(--accent); }
.badge.level-lead { background: var(--warn-soft); color: var(--warn); }
.badge.st-known { background: var(--good-soft); color: var(--good); }
.badge.st-learning { background: var(--warn-soft); color: var(--warn); }
.badge.freq { letter-spacing: -1px; }

/* Filters */
.filters { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin: 12px 0; }
.chip { border: 1px solid var(--border); background: var(--surface); color: var(--muted); border-radius: 99px; padding: 4px 12px; cursor: pointer; font: inherit; font-size: 13px; }
.chip.on { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); font-weight: 600; }
select, input[type="search"], input[type="text"], textarea {
  font: inherit; color: var(--text); background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 8px 10px;
}
input[type="search"] { width: 100%; font-size: 16px; }
textarea { width: 100%; min-height: 110px; resize: vertical; }

/* Question list */
.qlist { display: flex; flex-direction: column; gap: 8px; }
.qitem { padding: 0; }
.qitem summary { list-style: none; cursor: pointer; padding: 12px 16px; display: flex; gap: 12px; align-items: flex-start; }
.qitem summary::-webkit-details-marker { display: none; }
.qitem summary .qtext { flex: 1; font-weight: 500; }
.qitem summary .chev { color: var(--muted); transition: transform .15s; }
.qitem[open] summary .chev { transform: rotate(90deg); }
.qitem .qbody { padding: 0 16px 16px; border-top: 1px solid var(--border); }

/* Rendered markdown */
.prose { overflow-wrap: anywhere; }
.prose p { margin: 10px 0; }
.prose ul, .prose ol { padding-left: 22px; margin: 8px 0; }
.prose li { margin: 3px 0; }
.prose h3, .prose h4, .prose h5 { margin: 18px 0 8px; font-size: 16px; }
.prose code { font-family: var(--mono); font-size: .88em; background: var(--code-bg); padding: 1px 5px; border-radius: 4px; }
.prose pre { background: var(--code-bg); border: 1px solid var(--border); border-radius: 8px; padding: 12px; overflow-x: auto; }
.prose pre code { background: none; padding: 0; font-size: 13px; line-height: 1.5; }
.table-wrap { overflow-x: auto; margin: 10px 0; }
.prose table { border-collapse: collapse; font-size: 14px; min-width: 100%; }
.prose th, .prose td { border: 1px solid var(--border); padding: 6px 10px; text-align: left; vertical-align: top; }
.prose th { background: var(--surface-2); }
.task { background: var(--surface-2); border: 1px solid var(--border); border-radius: 8px; padding: 4px 14px; margin: 0 0 14px; }
.qbody .task { margin-top: 12px; }
.callout { border-left: 3px solid var(--accent); background: var(--accent-soft); padding: 4px 14px; border-radius: 0 8px 8px 0; margin: 12px 0; }

.theory { margin-bottom: 8px; }
.theory > summary { cursor: pointer; font-weight: 600; padding: 4px 0; }

/* Training card */
.session-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 10px; color: var(--muted); font-size: 14px; flex-wrap: wrap; }
.session-progress { height: 4px; background: var(--surface-2); border-radius: 99px; margin-bottom: 16px; overflow: hidden; }
.session-progress span { display: block; height: 100%; background: var(--accent); transition: width .2s; }
.flash { padding: 24px; }
.flash .q { font-size: 20px; font-weight: 600; margin: 12px 0 16px; line-height: 1.4; }
.answer { margin-top: 16px; padding-top: 8px; border-top: 1px dashed var(--border); }
.rate { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 16px; }
.hint { color: var(--muted); font-size: 13px; }
.timer { font-variant-numeric: tabular-nums; font-weight: 700; font-size: 18px; color: var(--text); }
.timer.low { color: var(--bad); }

.setup { display: grid; gap: 16px; }
.setup .row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; }
.topic-checks { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 6px; }
.topic-checks label { display: flex; gap: 8px; align-items: center; padding: 6px 10px; border: 1px solid var(--border); border-radius: 8px; cursor: pointer; background: var(--surface); }

.result-list { display: flex; flex-direction: column; gap: 6px; }
.result-row { display: flex; gap: 10px; align-items: center; justify-content: space-between; padding: 8px 12px; }
.score-big { font-size: 40px; font-weight: 800; }
.empty { text-align: center; color: var(--muted); padding: 40px 16px; }
.history td, .history th { padding: 6px 10px; text-align: left; border-bottom: 1px solid var(--border); font-size: 14px; }
.history { border-collapse: collapse; width: 100%; }

.footer { display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; color: var(--muted); font-size: 13px; padding-top: 16px; padding-bottom: 24px; border-top: 1px solid var(--border); }
.footer-actions { display: flex; gap: 14px; }
mark { background: var(--warn-soft); color: inherit; padding: 0 2px; border-radius: 3px; }

@media (max-width: 600px) {
  .flash { padding: 16px; }
  .flash .q { font-size: 18px; }
  h1 { font-size: 22px; }
}

/* Подробная теория */
.theory-refs { margin-top: 16px; padding: 10px 14px; background: var(--surface-2); border: 1px solid var(--border); border-radius: 8px; }
.theory-refs-head { font-weight: 600; font-size: 14px; margin-bottom: 4px; }
.theory-ref > summary { list-style: none; cursor: pointer; padding: 4px 0; color: var(--accent); display: flex; gap: 8px; }
.theory-ref > summary::-webkit-details-marker { display: none; }
.theory-ref > summary .chev { color: var(--muted); transition: transform .15s; }
.theory-ref[open] > summary .chev { transform: rotate(90deg); }
.theory-ref-body { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 4px 16px; margin: 6px 0 10px; }
.theory-topic { margin-bottom: 14px; }
.theory-topic h2 { margin-top: 0; }
.theory-topic h2 a { color: var(--text); }
.toc { margin: 0; padding-left: 24px; }
.toc li { margin: 4px 0; }
.crumbs { color: var(--muted); font-size: 14px; }
.lead-prose { color: var(--muted); }
.chapter { padding: 24px 28px; }
.chapter h1 { margin-bottom: 12px; }
.chapter .prose, .theory-ref-body .prose { font-size: 15.5px; line-height: 1.7; }
.chapter .prose h5, .theory-ref-body .prose h5 { font-size: 17px; margin-top: 26px; }
.pager { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 24px; }
.pager a { display: flex; flex-direction: column; gap: 2px; color: var(--text); }
.pager a:hover { border-color: var(--accent); text-decoration: none; }
.pager .next { text-align: right; }
.search-chapters { margin-bottom: 12px; }
.search-chapters ul { margin: 6px 0 0; padding-left: 20px; }
@media (max-width: 600px) {
  .chapter { padding: 16px; }
  .pager { grid-template-columns: 1fr; }
}

/* AI-интервьюер */
.chat { display: flex; flex-direction: column; gap: 10px; margin: 0 0 12px; }
.chat:empty { display: none; }
.msg { max-width: 85%; padding: 10px 14px; border-radius: 12px; background: var(--surface-2); overflow-wrap: anywhere; }
.msg.candidate { align-self: flex-end; background: var(--accent-soft); }
.msg-who { font-size: 12px; color: var(--muted); margin-bottom: 2px; }
.msg code, .ai-verdict code { font-family: var(--mono); font-size: .9em; background: var(--code-bg); padding: 1px 4px; border-radius: 4px; }
.thinking { animation: pulse 1.2s ease-in-out infinite; }
@keyframes pulse { 50% { opacity: .4; } }
.error { color: var(--bad); }
.ai-verdict { display: flex; gap: 16px; align-items: flex-start; padding: 16px; border-radius: var(--radius); border: 1px solid; margin-bottom: 12px; }
.ai-verdict.good { background: var(--good-soft); border-color: var(--good); }
.ai-verdict.warn { background: var(--warn-soft); border-color: var(--warn); }
.ai-verdict.bad { background: var(--bad-soft); border-color: var(--bad); }
.ai-verdict p { margin: 0 0 8px; }
.ai-verdict h4 { margin: 8px 0 4px; font-size: 14px; }
.ai-verdict ul { margin: 0; padding-left: 20px; }
.ai-score { font-size: 36px; font-weight: 700; line-height: 1; font-variant-numeric: tabular-nums; }
.ai-score span { font-size: 16px; color: var(--muted); font-weight: 400; }
.rate .btn.suggested { outline: 3px solid currentColor; outline-offset: 2px; }
@media (max-width: 640px) { .ai-verdict { flex-direction: column; gap: 8px; } .msg { max-width: 100%; } }

/* Выбор тем: заголовок со счётчиком и кнопками «Выбрать все / Снять все» */
.topic-head { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; margin-bottom: 8px; }
.topic-head .hint { margin-right: auto; }
.btn.small { padding: 4px 10px; font-size: 13px; }