/* Учебная платформа: светлая/тёмная тема через CSS-переменные */
:root {
  --bg: #f6f7f9;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --text: #1c2430;
  --muted: #5f6b7a;
  --border: #dde2e8;
  --accent: #2f6fde;
  --accent-text: #ffffff;
  --ok: #1f8a4c;
  --ok-bg: #e3f4ea;
  --bad: #c0392b;
  --bad-bg: #fbe7e5;
  --warn: #9a6700;
  --warn-bg: #fff4d6;
  --code-bg: #f3f4f7;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .08);
  --radius: 10px;
  --mono: ui-monospace, "Cascadia Code", "JetBrains Mono", Consolas, "Liberation Mono", monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #11151b; --surface: #181d25; --surface-2: #1f2530; --text: #e4e8ee; --muted: #97a2b0;
    --border: #2c3442; --accent: #6ea0ff; --accent-text: #0d1117; --ok: #4cc38a; --ok-bg: #16301f;
    --bad: #ff7b72; --bad-bg: #3a1d1b; --warn: #e3b341; --warn-bg: #3a2f12; --code-bg: #1d232d;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4); color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #11151b; --surface: #181d25; --surface-2: #1f2530; --text: #e4e8ee; --muted: #97a2b0;
  --border: #2c3442; --accent: #6ea0ff; --accent-text: #0d1117; --ok: #4cc38a; --ok-bg: #16301f;
  --bad: #ff7b72; --bad-bg: #3a1d1b; --warn: #e3b341; --warn-bg: #3a2f12; --code-bg: #1d232d;
  --shadow: 0 1px 2px rgba(0, 0, 0, .4); color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.6 var(--sans); }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.25; }
h1 { font-size: 1.7rem; margin: .3em 0 .5em; }
h2 { font-size: 1.3rem; margin: 1.2em 0 .5em; }
h3 { font-size: 1.08rem; margin: 1em 0 .4em; }
code, pre, .mono { font-family: var(--mono); font-size: .9em; }
code { background: var(--code-bg); padding: .1em .35em; border-radius: 4px; }
pre { background: var(--code-bg); padding: 12px 14px; border-radius: 8px; overflow-x: auto; border: 1px solid var(--border); }
pre code { background: none; padding: 0; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.nowrap { white-space: nowrap; }
.num { text-align: right; font-variant-numeric: tabular-nums; }
.err-text { color: var(--bad); }

/* шапка */
.topbar { position: sticky; top: 0; z-index: 10; display: flex; align-items: center; gap: 18px; padding: 10px 20px;
  background: var(--surface); border-bottom: 1px solid var(--border); }
.brand { font-weight: 700; color: var(--text); white-space: nowrap; }
.topbar nav { display: flex; gap: 4px; flex-wrap: wrap; flex: 1; }
.topbar nav a { color: var(--muted); padding: 6px 10px; border-radius: 6px; }
.topbar nav a.active, .topbar nav a:hover { color: var(--text); background: var(--surface-2); text-decoration: none; }
.theme-toggle { border: 1px solid var(--border); background: var(--surface-2); color: var(--text); border-radius: 6px;
  padding: 4px 10px; cursor: pointer; font-size: 1rem; }

.container { max-width: 1240px; margin: 0 auto; padding: 20px; }
.footer { text-align: center; color: var(--muted); font-size: .8rem; padding: 24px; }
.crumbs { color: var(--muted); font-size: .9rem; margin-bottom: 6px; }

.banner { margin: 0; padding: 10px 20px; border-bottom: 1px solid var(--border); }
.banner.warn { background: var(--warn-bg); color: var(--warn); }
.banner.err { background: var(--bad-bg); color: var(--bad); }
.banner summary { cursor: pointer; font-weight: 600; }

.card { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 20px;
  box-shadow: var(--shadow); margin-bottom: 18px; min-width: 0; }
.grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 14px; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.layout-2 { display: grid; grid-template-columns: minmax(0, 1fr) 380px; gap: 18px; align-items: start; }
.layout-task { display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); gap: 18px; align-items: start; }
.layout-task .work { position: sticky; top: 64px; }
@media (max-width: 1000px) {
  .layout-2, .layout-task, .grid-2 { grid-template-columns: 1fr; }
  .layout-task .work { position: static; }
}

/* главная */
.hero { display: flex; gap: 20px; justify-content: space-between; align-items: center; flex-wrap: wrap; margin-bottom: 10px; }
.hero > div:first-child { flex: 1 1 420px; }
.hero-side { display: flex; gap: 18px; align-items: center; flex-wrap: wrap; }
.stat { display: flex; flex-direction: column; }
.stat-num { font-size: 1.6rem; font-weight: 700; }
.module-card { color: var(--text); display: block; transition: border-color .15s; margin: 0; }
.module-card:hover { border-color: var(--accent); text-decoration: none; }
.module-card h3 { margin: .3em 0 .6em; }
.module-head { display: flex; justify-content: space-between; align-items: center; }
.module-id { font-family: var(--mono); font-weight: 700; color: var(--accent); }
.progress { height: 8px; background: var(--surface-2); border-radius: 99px; overflow: hidden; margin: 6px 0; }
.progress-bar { height: 100%; background: var(--ok); border-radius: 99px; }
.w40 { width: 40%; }

/* кнопки */
.btn { display: inline-flex; align-items: center; gap: 6px; border: 1px solid var(--border); background: var(--surface-2);
  color: var(--text); padding: 7px 14px; border-radius: 8px; cursor: pointer; font: inherit; font-size: .95rem; text-decoration: none; }
.btn:hover { border-color: var(--accent); text-decoration: none; }
.btn.primary { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }
.btn.ghost { background: transparent; }
.btn.small { padding: 3px 8px; font-size: .8rem; }
.btn[disabled] { opacity: .6; cursor: progress; }
.kbd { font-size: .72rem; opacity: .75; border: 1px solid currentColor; border-radius: 4px; padding: 0 4px; }
.actions { display: flex; gap: 8px; flex-wrap: wrap; align-items: center; margin: 10px 0; }

/* бейджи */
.badges { display: flex; flex-wrap: wrap; gap: 6px; margin: 4px 0; }
.badge { display: inline-block; font-size: .75rem; padding: 2px 8px; border-radius: 99px; background: var(--surface-2);
  border: 1px solid var(--border); color: var(--muted); white-space: nowrap; }
.badge.ok { background: var(--ok-bg); color: var(--ok); border-color: transparent; }
.badge.bad { background: var(--bad-bg); color: var(--bad); border-color: transparent; }
.badge.type-sql { color: var(--accent); }
.badge.diff-1 { color: var(--ok); }
.badge.diff-2 { color: var(--warn); }
.badge.diff-3 { color: var(--bad); }
.badge.topic { font-family: var(--mono); }

/* список задач */
.task-list { list-style: none; padding: 0; margin: 0; }
.task-list li { padding: 8px 0; border-bottom: 1px solid var(--border); }
.task-list li:last-child { border-bottom: 0; }
.task-list a { display: flex; gap: 8px; align-items: baseline; color: var(--text); }
.task-id { font-family: var(--mono); font-size: .85rem; color: var(--muted); white-space: nowrap; }
.status-dot { width: 10px; height: 10px; border-radius: 50%; flex: none; background: var(--border); display: inline-block; }
.status-dot.solved { background: var(--ok); }
.status-dot.attempted { background: var(--warn); }
.links { padding-left: 18px; }

/* markdown */
.md { overflow-wrap: anywhere; }
.md img { max-width: 100%; }
.md table, .tbl { border-collapse: collapse; width: 100%; margin: 10px 0; font-size: .92rem; }
.md th, .md td, .tbl th, .tbl td { border: 1px solid var(--border); padding: 6px 9px; text-align: left; vertical-align: top; }
.md th, .tbl th { background: var(--surface-2); }
.md table { display: block; overflow-x: auto; }
.md blockquote { margin: 10px 0; padding: 8px 14px; border-left: 4px solid var(--accent); background: var(--surface-2); border-radius: 0 8px 8px 0; }
.md blockquote p { margin: .3em 0; }
.md details, details.sandbox { border: 1px solid var(--border); border-radius: 8px; padding: 8px 12px; margin: 10px 0; background: var(--surface-2); }
.md details summary, details.sandbox summary { cursor: pointer; font-weight: 600; }
.md details[open] summary { margin-bottom: 6px; }
.mermaid { background: var(--surface); text-align: center; overflow-x: auto; margin: 10px 0; }
.md .headerlink { display: none; }
.flow-wrap { overflow-x: auto; }
.mermaid.flow svg { min-width: 980px; }
.tbl.compact td, .tbl.compact th { padding: 4px 8px; }
.tbl.kv td:first-child { color: var(--muted); }
.tbl tr.hl td { font-weight: 700; }
.tbl tr.good td.num { color: var(--ok); }
.tbl tr.bad td.num { color: var(--bad); }

/* задача */
.task-head h1 { margin-bottom: .2em; }
.criteria-plain { padding-left: 18px; }
.code-editor { width: 100%; min-height: 220px; resize: vertical; font: 14px/1.5 var(--mono); padding: 10px 12px;
  border-radius: 8px; border: 1px solid var(--border); background: var(--code-bg); color: var(--text); tab-size: 2; }
.code-editor.small { min-height: 120px; }
.code-editor.tall { min-height: 380px; font-family: var(--sans); font-size: 15px; }
.code-editor:focus, input:focus, select:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
input, select { font: inherit; padding: 6px 9px; border-radius: 6px; border: 1px solid var(--border); background: var(--surface);
  color: var(--text); width: 100%; }
.answers { display: grid; gap: 10px; }
.field { display: grid; gap: 4px; }
.field > span:first-child { font-size: .92rem; }
.field-status { font-size: .85rem; min-height: 1em; }
.field-status.ok { color: var(--ok); }
.field-status.bad { color: var(--bad); }
.result { margin-top: 10px; }
.result:empty { display: none; }
.feedback { border-radius: 8px; padding: 10px 14px; border: 1px solid var(--border); background: var(--surface-2); }
.feedback.ok { background: var(--ok-bg); border-color: transparent; }
.feedback.bad { background: var(--bad-bg); border-color: transparent; }
.feedback.pending { background: var(--warn-bg); border-color: transparent; }
.feedback .title { font-weight: 700; margin-bottom: 4px; }
.feedback pre { background: transparent; border: 0; padding: 0; margin: 0; white-space: pre-wrap; font-size: .85rem; }
.mm-list { list-style: none; padding: 0; margin: 6px 0; }
.mm-list li { margin: 2px 0; }
.mm-list .hit { color: var(--ok); }
.mm-list .miss { color: var(--bad); }
.table-wrap { overflow: auto; max-height: 420px; border: 1px solid var(--border); border-radius: 8px; }
.table-wrap .tbl { margin: 0; font-size: .85rem; font-family: var(--mono); }
.table-wrap th { position: sticky; top: 0; }
.tbl td.null { color: var(--muted); font-style: italic; }
.tabs { display: flex; gap: 4px; margin-bottom: 6px; }
.tab { border: 1px solid var(--border); background: transparent; color: var(--muted); border-radius: 6px; padding: 3px 10px; cursor: pointer; font: inherit; font-size: .85rem; }
.tab.active { background: var(--surface-2); color: var(--text); }
.preview { min-height: 380px; border: 1px dashed var(--border); border-radius: 8px; padding: 10px 14px; }
.selfscore { border-top: 1px solid var(--border); margin-top: 14px; }
.check-item { display: flex; gap: 10px; align-items: flex-start; padding: 6px 0; cursor: pointer; }
.check-item input { width: auto; margin-top: 5px; }
.solution { border-left: 4px solid var(--ok); }
.task-nav { display: flex; justify-content: space-between; margin: 10px 0 30px; }

/* данные и логи */
.schema-table { border-bottom: 1px solid var(--border); padding: 6px 0; }
.schema-table summary { cursor: pointer; }
.filters { display: flex; gap: 12px; flex-wrap: wrap; align-items: flex-end; }
.filters label { display: grid; gap: 3px; font-size: .85rem; color: var(--muted); min-width: 140px; }
.filters label.grow { flex: 1 1 240px; }
.log-view { overflow-x: auto; }
.tbl.log { font-size: .82rem; }
.tbl.log td.mono { white-space: pre-wrap; word-break: break-word; min-width: 280px; }
.tbl.log tr.lvl-error .lvl { color: var(--bad); font-weight: 700; }
.tbl.log tr.lvl-warn .lvl, .tbl.log tr.lvl-warning .lvl { color: var(--warn); font-weight: 700; }
.tbl.log tr.lvl-error td { background: color-mix(in srgb, var(--bad-bg) 55%, transparent); }
.pager { display: flex; gap: 8px; align-items: center; justify-content: center; margin: 14px 0; flex-wrap: wrap; }

/* лаба */
.form-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); gap: 10px; align-items: end; }
.form-grid label, .inline-form label { display: grid; gap: 3px; font-size: .85rem; color: var(--muted); }
.form-grid .actions { margin: 0; }
.inline-form { display: flex; gap: 10px; align-items: flex-end; flex-wrap: wrap; }
.inline-form label { min-width: 240px; }

@media (max-width: 640px) {
  .container { padding: 12px; }
  .topbar { padding: 8px 12px; gap: 10px; flex-wrap: wrap; }
  .card { padding: 14px; }
  h1 { font-size: 1.4rem; }
}

/* вход и пользователь (T2) */
.topbar .brand { margin-right: auto; }
.user-box { display: flex; align-items: center; gap: 8px; margin: 0; }
.user-name { color: var(--muted); max-width: 14rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.login-card { max-width: 30rem; margin: 3rem auto; }
.login-widget { margin-top: 12px; min-height: 40px; }
.badge.dev { border: 1px solid var(--bad); color: var(--bad); background: transparent; text-transform: none; }

/* доступ к платной части (T4) */
.badge.lock { border: 1px solid var(--border); color: var(--muted); }
.locked-task { display: block; opacity: .65; cursor: not-allowed; }
.locked-note { margin-top: 16px; padding-top: 12px; border-top: 1px dashed var(--border); }
.locked-card { max-width: 36rem; margin: 3rem auto; }

/* ---------- админка (T6) */
.admin-nav, .admin-tabs { display: flex; flex-wrap: wrap; gap: 6px 14px; margin: 0 0 14px; }
.admin-nav a, .admin-tabs a { padding: 4px 0; border-bottom: 2px solid transparent; }
.admin-nav a.active, .admin-tabs a.active { border-bottom-color: var(--accent); font-weight: 600; }
.banner.ok { background: var(--ok-bg); color: var(--ok); }
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; margin-bottom: 14px; }
.stat { display: flex; flex-direction: column; gap: 4px; }
.stat-num { font-size: 1.9rem; font-weight: 700; }
.stat-label { color: var(--muted); font-size: .85rem; }
.inline-form { display: inline-flex; flex-wrap: wrap; align-items: center; gap: 6px; margin: 2px 0; }
.inline-form.stack { display: flex; margin-top: 8px; }
.inline-form.filter { margin-bottom: 10px; }
.inline-form input[type=text], .inline-form input[type=search], .inline-form input[type=number] {
  padding: 4px 8px; border: 1px solid var(--border); border-radius: 6px; background: var(--surface); color: inherit; font: inherit; }
.inline-form input[type=number] { width: 6em; }
.admin-table { max-height: none; }
.admin-table .tbl { font-family: inherit; font-size: .85rem; }
.actions-cell { min-width: 16em; }
.report-text { white-space: pre-wrap; word-break: break-word; max-width: 34em; }
.invite-link { word-break: break-all; font-size: 1rem; }
.new-invite { border-color: var(--ok); }
.pager { display: flex; align-items: center; gap: 12px; margin: 12px 0; }
.report { margin: 16px 0; }
.report summary { cursor: pointer; font-weight: 600; }
.report textarea { width: 100%; box-sizing: border-box; font: inherit; padding: 6px 8px; }