/* TRAIXON Tutorials. Colours and type from the TRAIXON design system
   (tx-design-system/ds/tokens.css): ink, paper, teal as the one
   interaction colour, Inter for text, JetBrains Mono for labels. */
:root {
  --ink: #23303F; --text: #2A3340; --paper: #F7F9FA; --card: #FFFFFF;
  --surface-2: #EEF2F4; --slate: #5E6B78; --line: #E4E9EC;
  --accent: #00948D; --accent-deep: #00736D; --accent-soft: #D8F2EE;
  --stage: #151B24; --danger: #975C57; --done: #4C7C56; --done-soft: #E3F1E4;
  --r-card: 16px; --r-input: 10px; --r-pill: 999px;
  --shadow: 0 6px 18px rgba(35, 48, 63, .08);
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --ink: #EEF2F5; --text: #DCE3E9; --paper: #151B24; --card: #212A36;
    --surface-2: #2A3441; --slate: #9AA6B2; --line: #37424F;
    --accent: #3FB8B0; --accent-deep: #6DD7C4; --accent-soft: #1E3B3A;
    --done: #89CD97; --done-soft: #243A2B; --danger: #E8948D;
    --shadow: 0 6px 18px rgba(0, 0, 0, .3); color-scheme: dark;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body { background: var(--paper); color: var(--text); font: 400 15px/1.55 'Inter', system-ui, sans-serif;
  -webkit-font-smoothing: antialiased; }
a { color: var(--accent-deep); }
button { font: inherit; }
.eyebrow { font: 500 11px/1 'JetBrains Mono', ui-monospace, monospace; letter-spacing: .16em;
  text-transform: uppercase; color: var(--slate); }
.wordmark { font: 300 22px/1 'Inter', sans-serif; letter-spacing: .32em; color: var(--ink); }
.btn { display: inline-flex; align-items: center; justify-content: center; gap: 8px; height: 40px;
  padding: 0 18px; border: 0; border-radius: var(--r-pill); background: var(--accent); color: #fff;
  font-weight: 600; cursor: pointer; text-decoration: none; }
.btn:hover { background: var(--accent-deep); }
.btn--ghost { background: var(--surface-2); color: var(--ink); font-weight: 500; }
.btn--ghost:hover { background: var(--line); }
.btn--small { height: 32px; padding: 0 14px; font-size: 13px; }
.btn:disabled { opacity: .55; cursor: default; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
input[type=text], input[type=email], input[type=password] { width: 100%; height: 44px; padding: 0 14px;
  border: 1px solid transparent; border-radius: var(--r-input); background: var(--surface-2);
  color: var(--ink); font: inherit; }
input:focus { outline: none; border-color: var(--accent); background: var(--card); }
label { display: block; margin: 14px 0 6px; font-size: 13px; font-weight: 500; color: var(--ink); }
.status { min-height: 20px; margin: 12px 0 0; font-size: 13px; color: var(--slate); }
.status.err { color: var(--danger); }
.status.ok { color: var(--done); }

/* ---- sign in ---- */
.auth { min-height: 100vh; display: grid; place-items: center; padding: 24px 16px; }
.auth__card { width: 100%; max-width: 420px; background: var(--card); border-radius: var(--r-card);
  box-shadow: var(--shadow); padding: 36px 32px 28px; }
.auth__card h1 { margin: 22px 0 6px; font: 600 26px/1.2 'Inter', sans-serif; color: var(--ink); letter-spacing: -.01em; }
.auth__card p.lead { margin: 0 0 8px; color: var(--slate); }
.auth__tabs { display: flex; gap: 4px; margin: 20px 0 4px; padding: 4px; border-radius: var(--r-pill); background: var(--surface-2); }
.auth__tabs button { flex: 1; height: 34px; border: 0; border-radius: var(--r-pill); background: transparent;
  color: var(--slate); font-weight: 500; cursor: pointer; }
.auth__tabs button.on { background: var(--card); color: var(--ink); box-shadow: 0 1px 3px rgba(0,0,0,.08); }
.auth__card .btn { width: 100%; margin-top: 20px; }

/* ---- app ---- */
.top { position: sticky; top: 0; z-index: 10; display: flex; align-items: center; gap: 16px;
  padding: 14px max(16px, calc((100vw - 1120px) / 2)); background: color-mix(in srgb, var(--paper) 88%, transparent);
  backdrop-filter: blur(10px); border-bottom: 1px solid var(--line); }
.top__spacer { flex: 1; }
.top__progress { display: flex; align-items: center; gap: 10px; font-size: 13px; color: var(--slate); }
.bar { width: 120px; height: 6px; border-radius: 3px; background: var(--surface-2); overflow: hidden; }
.bar > i { display: block; height: 100%; background: var(--accent); border-radius: 3px; transition: width .3s; }
.menu { position: relative; }
.menu__list { position: absolute; right: 0; top: calc(100% + 6px); min-width: 220px; padding: 6px;
  background: var(--card); border: 1px solid var(--line); border-radius: 12px; box-shadow: var(--shadow); }
.menu__list[hidden] { display: none; }
.menu__list button, .menu__list a { display: block; width: 100%; padding: 9px 12px; border: 0; border-radius: 8px;
  background: none; color: var(--ink); text-align: left; text-decoration: none; font-size: 14px; cursor: pointer; }
.menu__list button:hover, .menu__list a:hover { background: var(--surface-2); }
.menu__who { padding: 8px 12px 10px; border-bottom: 1px solid var(--line); margin-bottom: 4px; font-size: 13px; color: var(--slate); }

main { max-width: 1120px; margin: 0 auto; padding: 36px 16px 80px; }
.hero h1 { margin: 10px 0 8px; font: 600 34px/1.15 'Inter', sans-serif; color: var(--ink); letter-spacing: -.02em; text-wrap: balance; }
.hero p { margin: 0; max-width: 62ch; color: var(--slate); font-size: 16px; }
.hero .btn { margin-top: 20px; }
.part { margin-top: 44px; }
.part__head { display: flex; align-items: baseline; gap: 14px; flex-wrap: wrap; margin-bottom: 16px; }
.part__head h2 { margin: 0; font: 600 21px/1.3 'Inter', sans-serif; color: var(--ink); }
.part__head .count { font-size: 13px; color: var(--slate); font-variant-numeric: tabular-nums; }
.part__head p { flex-basis: 100%; margin: 0; color: var(--slate); max-width: 65ch; }
.grid { display: grid; gap: 16px; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); }
.card { display: flex; flex-direction: column; text-align: left; border: 0; padding: 0; overflow: hidden;
  border-radius: var(--r-card); background: var(--card); box-shadow: 0 1px 2px rgba(35,48,63,.06);
  cursor: pointer; transition: box-shadow .16s; color: inherit; text-decoration: none; }
.card:hover { box-shadow: var(--shadow); }
.card__img { position: relative; aspect-ratio: 16 / 10; background: var(--stage); overflow: hidden; }
.card__img img { width: 100%; height: 100%; object-fit: cover; object-position: top left; display: block; opacity: .92; }
.card__time { position: absolute; right: 10px; bottom: 10px; padding: 3px 8px; border-radius: 6px;
  background: rgba(21,27,36,.8); color: #fff; font: 500 11px/1.3 'JetBrains Mono', monospace; }
.card__done { position: absolute; left: 10px; top: 10px; display: none; align-items: center; gap: 5px;
  padding: 4px 9px; border-radius: var(--r-pill); background: var(--done-soft); color: var(--done);
  font: 600 11px/1.2 'Inter', sans-serif; }
.card.is-done .card__done { display: inline-flex; }
.card__body { padding: 14px 16px 16px; display: flex; flex-direction: column; gap: 5px; }
.card__num { font: 500 11px/1 'JetBrains Mono', monospace; letter-spacing: .12em; color: var(--slate); }
.card__title { font: 600 15px/1.35 'Inter', sans-serif; color: var(--ink); }
.card__sum { font-size: 13px; color: var(--slate); }

/* ---- lesson ---- */
.lesson { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 28px; align-items: start; }
.player { border-radius: var(--r-card); overflow: hidden; background: var(--stage); box-shadow: var(--shadow); }
.player video { display: block; width: 100%; aspect-ratio: 16 / 10; background: var(--stage); }
.lesson__text h1 { margin: 22px 0 8px; font: 600 26px/1.25 'Inter', sans-serif; color: var(--ink); text-wrap: balance; }
.lesson__text p { max-width: 65ch; }
.lesson__text ul { padding-left: 20px; max-width: 65ch; }
.lesson__actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 18px; }
.btn.is-done { background: var(--done-soft); color: var(--done); }
.side { position: sticky; top: 84px; background: var(--card); border-radius: var(--r-card); padding: 14px 8px;
  box-shadow: 0 1px 2px rgba(35,48,63,.06); max-height: calc(100vh - 110px); overflow: auto; }
.side .eyebrow { padding: 4px 10px 8px; display: block; }
.side a { display: flex; gap: 10px; align-items: baseline; padding: 7px 10px; border-radius: 8px;
  color: var(--text); text-decoration: none; font-size: 13.5px; line-height: 1.35; }
.side a:hover { background: var(--surface-2); }
.side a.on { background: var(--accent-soft); color: var(--ink); font-weight: 600; }
.side a .n { flex: none; width: 22px; font: 500 11px/1.35 'JetBrains Mono', monospace; color: var(--slate); }
.side a.done .n { color: var(--done); }
.back { display: inline-flex; align-items: center; gap: 6px; margin-bottom: 16px; font-size: 14px; color: var(--slate); text-decoration: none; }

/* ---- admin ---- */
table { width: 100%; border-collapse: collapse; background: var(--card); border-radius: var(--r-card); overflow: hidden; }
th, td { padding: 11px 14px; text-align: left; border-bottom: 1px solid var(--line); font-size: 14px; }
th { font: 500 11px/1 'JetBrains Mono', monospace; letter-spacing: .12em; text-transform: uppercase; color: var(--slate); }
td.num { font-variant-numeric: tabular-nums; }
.pill { display: inline-block; padding: 3px 9px; border-radius: var(--r-pill); font-size: 12px; font-weight: 600; }
.pill--ok { background: var(--done-soft); color: var(--done); }
.pill--wait { background: #F7EBD2; color: #866A35; }
.table-wrap { overflow-x: auto; }

@media (max-width: 860px) {
  .lesson { grid-template-columns: minmax(0, 1fr); }
  .side { position: static; max-height: none; }
  .top__progress .bar { width: 70px; }
  .hero h1 { font-size: 27px; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }