/* dojo — one stylesheet, no framework. Tokens first; everything below uses them,
   so dark mode is only the token block. Diagrams (content/diagrams/*.svg) are
   inlined and coloured from here too (.d-*). */
:root {
  --bg: #f6f7f9; --bg-soft: #eef0f4; --card: #ffffff; --fg: #15181d; --fg-soft: #3b4250;
  --muted: #6b7280; --line: #e3e6eb; --line-strong: #c9ced8;
  --accent: #4f46e5; --accent-fg: #ffffff; --accent-soft: #eef0ff; --accent-line: #c7c9ff;
  --ok: #15803d; --ok-soft: #e8f6ee; --warn: #b45309; --warn-soft: #fdf3e4; --err: #b91c1c; --err-soft: #fdecec;
  --code-bg: #0f172a; --code-fg: #e2e8f0; --inline-code: #eef0f4;
  --shadow: 0 1px 2px rgba(16, 24, 40, .06), 0 1px 3px rgba(16, 24, 40, .08);
  --shadow-lg: 0 10px 30px -12px rgba(16, 24, 40, .25);
  --radius: 14px;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0d1016; --bg-soft: #151a22; --card: #161b24; --fg: #e8eaee; --fg-soft: #c2c7d0;
    --muted: #8b93a1; --line: #262d39; --line-strong: #3a4352;
    --accent: #8b87ff; --accent-fg: #0d1016; --accent-soft: #1f2140; --accent-line: #3e3f86;
    --ok: #4ade80; --ok-soft: #12291c; --warn: #fbbf24; --warn-soft: #2b2210; --err: #f87171; --err-soft: #2d1515;
    --code-bg: #0a0d12; --code-fg: #e2e8f0; --inline-code: #222936;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4); --shadow-lg: 0 12px 30px -12px rgba(0, 0, 0, .6);
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--fg);
  font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif; }
a { color: var(--accent); text-decoration: none; } a:hover { text-decoration: underline; }
h1, h2, h3 { line-height: 1.25; letter-spacing: -.01em; }
h1 { font-size: 1.75rem; margin: 0 0 .4rem; } h2 { font-size: 1.2rem; margin: 0 0 .6rem; } h3 { font-size: 1.02rem; margin: 1.2rem 0 .4rem; }
p { margin: .5rem 0; }
.muted { color: var(--muted); } .small { font-size: .86rem; } .err { color: var(--err); }
.icon { width: 1.15em; height: 1.15em; vertical-align: -.2em; flex: none; }
.icon path, .icon circle, .icon rect, .icon line, .icon polyline { fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }

/* --- frame ------------------------------------------------------------- */
.top { position: sticky; top: 0; z-index: 10; background: color-mix(in srgb, var(--card) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px); border-bottom: 1px solid var(--line); }
.top-in { max-width: 1120px; margin: 0 auto; padding: 10px 20px; display: flex; align-items: center; gap: 20px; }
.brand { display: flex; align-items: center; gap: 8px; font-weight: 750; font-size: 1.12rem; color: var(--fg); letter-spacing: -.02em; }
.brand:hover { text-decoration: none; }
.brand .logo { width: 28px; height: 28px; border-radius: 8px; background: var(--accent); color: var(--accent-fg);
  display: grid; place-items: center; font-size: .9rem; }
.nav { display: flex; gap: 4px; flex: 1; flex-wrap: wrap; }
.nav a { color: var(--fg-soft); padding: 6px 12px; border-radius: 999px; font-weight: 550; font-size: .95rem; display: inline-flex; gap: 6px; align-items: center; }
.nav a:hover { background: var(--bg-soft); text-decoration: none; }
.nav a.on { background: var(--accent-soft); color: var(--accent); }
.who { display: flex; align-items: center; gap: 10px; color: var(--muted); font-size: .9rem; }
main { max-width: 1120px; margin: 0 auto; padding: 24px 20px 64px; }
main.narrow { max-width: 820px; }
footer { text-align: center; color: var(--muted); font-size: .8rem; padding: 0 16px 32px; }

/* --- building blocks --------------------------------------------------- */
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 20px 22px; box-shadow: var(--shadow); }
.card + .card { margin-top: 16px; }
.section { margin-top: 36px; }
.section-head { display: flex; align-items: baseline; justify-content: space-between; gap: 12px; margin-bottom: 12px; }
.section-head h2 { margin: 0; }
.grid { display: grid; gap: 16px; }
.grid.cols-3 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid.cols-2 { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); }
.grid > .card + .card { margin-top: 0; }
.row { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; }

.btn, button { font: inherit; font-weight: 600; display: inline-flex; align-items: center; gap: 8px; justify-content: center;
  padding: 10px 18px; border-radius: 10px; border: 1px solid var(--accent); background: var(--accent); color: var(--accent-fg);
  cursor: pointer; text-decoration: none; transition: transform .05s, box-shadow .15s; white-space: nowrap; }
.btn:hover, button:hover { text-decoration: none; box-shadow: var(--shadow-lg); }
.btn:active, button:active { transform: translateY(1px); }
.btn.big { padding: 13px 24px; font-size: 1.05rem; border-radius: 12px; }
.btn.ghost, button.ghost { background: transparent; color: var(--accent); border-color: var(--accent-line); }
.btn.quiet, button.quiet { background: var(--bg-soft); color: var(--fg-soft); border-color: transparent; }
button.link { background: none; border: none; color: var(--muted); padding: 6px 8px; font-weight: 500; }
button.link:hover { color: var(--fg); box-shadow: none; }
button[disabled] { opacity: .45; cursor: not-allowed; box-shadow: none; }

label { display: block; font-weight: 550; font-size: .92rem; color: var(--fg-soft); margin: 10px 0 4px; }
.hint { font-weight: 400; color: var(--muted); font-size: .85rem; }
input, textarea, select { width: 100%; font: inherit; color: var(--fg); background: var(--card); padding: 10px 12px;
  border: 1px solid var(--line-strong); border-radius: 10px; transition: border-color .15s, box-shadow .15s; }
input:focus, textarea:focus, select:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
input[type=checkbox], input[type=radio] { width: auto; accent-color: var(--accent); }
input.num { width: 6em; }
textarea.mono { font-family: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, monospace; font-size: .9rem; line-height: 1.5; }

.chip { display: inline-flex; align-items: center; gap: 5px; font-size: .76rem; font-weight: 600; padding: 2px 9px; border-radius: 999px;
  background: var(--bg-soft); color: var(--fg-soft); white-space: nowrap; }
.chip.accent { background: var(--accent-soft); color: var(--accent); }
.chip.ok { background: var(--ok-soft); color: var(--ok); } .chip.warn { background: var(--warn-soft); color: var(--warn); }
.chip.err { background: var(--err-soft); color: var(--err); }
.chip.exam { background: transparent; border: 1px solid var(--line-strong); color: var(--muted); }

.flash { padding: 12px 16px; border-radius: 12px; margin-bottom: 18px; font-weight: 500; }
.flash.ok { background: var(--ok-soft); color: var(--ok); } .flash.err { background: var(--err-soft); color: var(--err); }

progress { appearance: none; -webkit-appearance: none; width: 100%; height: 8px; border: none; border-radius: 999px; background: var(--bg-soft); overflow: hidden; }
progress::-webkit-progress-bar { background: var(--bg-soft); border-radius: 999px; }
progress::-webkit-progress-value { background: var(--accent); border-radius: 999px; }
progress::-moz-progress-bar { background: var(--accent); border-radius: 999px; }
progress.ok::-webkit-progress-value { background: var(--ok); } progress.ok::-moz-progress-bar { background: var(--ok); }
progress.warn::-webkit-progress-value { background: var(--warn); } progress.warn::-moz-progress-bar { background: var(--warn); }

details > summary { cursor: pointer; list-style: none; }
details > summary::-webkit-details-marker { display: none; }

/* --- start page -------------------------------------------------------- */
.hello { display: flex; align-items: flex-end; justify-content: space-between; gap: 16px; flex-wrap: wrap; margin-bottom: 20px; }
.hello h1 { margin: 0; font-size: 1.9rem; }
.stats { display: flex; gap: 10px; flex-wrap: wrap; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 8px 14px; min-width: 96px; }
.stat b { display: block; font-size: 1.25rem; line-height: 1.2; }
.stat span { font-size: .78rem; color: var(--muted); }
.hero { display: grid; grid-template-columns: 1fr auto; gap: 20px; align-items: center; padding: 26px 28px;
  background: linear-gradient(135deg, var(--accent-soft), var(--card) 70%); border-color: var(--accent-line); }
.eyebrow { text-transform: uppercase; letter-spacing: .08em; font-size: .74rem; font-weight: 700; color: var(--accent); }
.hero h2 { font-size: 1.45rem; margin: 6px 0; }
.hero .where { color: var(--muted); font-size: .92rem; }
@media (max-width: 640px) { .hero { grid-template-columns: 1fr; } }
.learn-box { display: flex; gap: 10px; align-items: stretch; margin-top: 8px; }
.learn-box input { font-size: 1.05rem; padding: 13px 16px; }
.learn-more summary { color: var(--accent); font-weight: 550; font-size: .92rem; margin-top: 12px; }
.pending { display: flex; gap: 10px; align-items: center; padding: 10px 14px; border-radius: 10px; background: var(--bg-soft); margin-top: 12px; font-size: .94rem; }
.spinner { width: 16px; height: 16px; border-radius: 50%; border: 2px solid var(--accent-line); border-top-color: var(--accent); animation: spin .8s linear infinite; flex: none; }
@keyframes spin { to { transform: rotate(360deg); } }
.list { list-style: none; margin: 0; padding: 0; }
.list li { display: flex; gap: 10px; align-items: center; padding: 9px 0; border-top: 1px solid var(--line); }
.list li:first-child { border-top: none; }
.list .grow { flex: 1; min-width: 0; }
.meter { display: grid; grid-template-columns: 52px 1fr 44px; gap: 10px; align-items: center; margin: 8px 0; font-size: .92rem; }
.meter .pct { text-align: right; color: var(--muted); font-variant-numeric: tabular-nums; }
.course-card { display: flex; flex-direction: column; gap: 10px; color: var(--fg); transition: border-color .15s, transform .1s; }
.course-card:hover { border-color: var(--accent-line); text-decoration: none; transform: translateY(-1px); }
.course-card h3 { margin: 0; font-size: 1.05rem; }
.course-card .meta { display: flex; justify-content: space-between; gap: 8px; font-size: .84rem; color: var(--muted); }
.course-card.remedial { border-color: var(--warn); }
.empty { text-align: center; padding: 30px 20px; }
.steps { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 14px; margin: 18px 0; text-align: left; }
.step { background: var(--bg-soft); border-radius: 12px; padding: 14px 16px; }
.step b { display: block; margin-bottom: 4px; }

/* --- course page ------------------------------------------------------- */
.course-head { display: grid; grid-template-columns: 1fr 240px; gap: 24px; align-items: start; }
@media (max-width: 760px) { .course-head { grid-template-columns: 1fr; } }
.ring { width: 120px; height: 120px; margin: 0 auto 12px; display: block; }
.ring circle { fill: none; stroke-width: 10; }
.ring .bg { stroke: var(--bg-soft); } .ring .fg { stroke: var(--accent); stroke-linecap: round; transform: rotate(-90deg); transform-origin: 50% 50%; }
.ring text { fill: var(--fg); font-weight: 750; font-size: 22px; }
.modules { margin-top: 24px; }
.module { position: relative; padding-left: 52px; }
.module + .module { margin-top: 14px; }
.module::before { content: ""; position: absolute; left: 17px; top: 50px; bottom: -14px; width: 2px; background: var(--line); }
.module:last-child::before { display: none; }
.module .num { position: absolute; left: 0; top: 16px; width: 36px; height: 36px; border-radius: 50%; display: grid; place-items: center;
  font-weight: 700; background: var(--card); border: 2px solid var(--line-strong); color: var(--muted); }
.module.current .num { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }
.module.done .num { border-color: var(--ok); background: var(--ok); color: var(--card); }
.module > details { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); }
.module.current > details { border-color: var(--accent-line); }
.module summary { padding: 16px 20px; display: grid; grid-template-columns: 1fr 150px; gap: 16px; align-items: center; }
.module summary h3 { margin: 0; }
.module summary .goal { color: var(--muted); font-size: .9rem; margin-top: 2px; }
.module .tasks { list-style: none; margin: 0; padding: 6px 10px 10px; border-top: 1px solid var(--line); }
.task-row { display: flex; align-items: center; gap: 12px; padding: 9px 10px; border-radius: 10px; color: var(--fg); }
.task-row:hover { background: var(--bg-soft); text-decoration: none; }
.kind { width: 34px; height: 34px; border-radius: 9px; display: grid; place-items: center; background: var(--bg-soft); color: var(--fg-soft); flex: none; }
.task-row.done .kind { background: var(--ok-soft); color: var(--ok); }
.task-row .t { flex: 1; min-width: 0; }
.task-row .t b { font-weight: 550; } .task-row .sub { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 3px; }
.task-row .score { font-size: .85rem; font-weight: 650; color: var(--ok); white-space: nowrap; }

/* --- task page --------------------------------------------------------- */
.crumbs { display: flex; gap: 8px; align-items: center; flex-wrap: wrap; font-size: .9rem; color: var(--muted); margin-bottom: 14px; }
.dots { display: flex; gap: 5px; margin-left: auto; flex-wrap: wrap; }
.dots a { width: 10px; height: 10px; border-radius: 50%; background: var(--line-strong); }
.dots a.done { background: var(--ok); } .dots a.here { background: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.task-head { display: flex; gap: 16px; align-items: flex-start; }
.kind-big { width: 52px; height: 52px; border-radius: 14px; display: grid; place-items: center; background: var(--accent-soft); color: var(--accent); flex: none; }
.kind-big .icon { width: 26px; height: 26px; }
.task-head .meta { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; margin-top: 6px; }
.howto { display: flex; gap: 12px; align-items: flex-start; padding: 12px 16px; border-radius: 12px; background: var(--bg-soft); margin: 18px 0 6px; font-size: .94rem; }
.howto.env-sandbox { background: var(--accent-soft); } .howto.env-cluster { background: var(--ok-soft); }
.howto > .icon { margin-top: 3px; color: var(--accent); }
.prose { font-size: 1.02rem; }
.prose h2, .prose h3, .prose h4 { margin-top: 1.4rem; }
.prose ul, .prose ol { padding-left: 1.3rem; } .prose li { margin: 4px 0; }
.prose code, .list code, .howto code, p code, td code, li code { background: var(--inline-code); padding: 1px 6px; border-radius: 6px; font-size: .88em;
  font-family: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, monospace; }
.howto code { background: var(--card); }
.code { position: relative; margin: 12px 0; }
.code pre { background: var(--code-bg); color: var(--code-fg); padding: 14px 16px; border-radius: 12px; overflow-x: auto; font-size: .86rem; line-height: 1.55; margin: 0; }
.code pre code { background: none; padding: 0; font-family: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, monospace; }
.code .copy { position: absolute; top: 8px; right: 8px; padding: 3px 10px; font-size: .75rem; border-radius: 7px; background: rgba(255,255,255,.08);
  border: 1px solid rgba(255,255,255,.18); color: #cbd5e1; opacity: 0; transition: opacity .15s; }
.code:hover .copy, .code .copy:focus { opacity: 1; }
.prose blockquote { margin: 12px 0; padding: 8px 16px; border-left: 3px solid var(--accent); background: var(--accent-soft); border-radius: 0 10px 10px 0; }
.tablewrap { overflow-x: auto; margin: 12px 0; border: 1px solid var(--line); border-radius: 12px; }
table { border-collapse: collapse; width: 100%; font-size: .92rem; }
th { background: var(--bg-soft); font-weight: 650; color: var(--fg-soft); }
th, td { text-align: left; padding: 9px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
tr:last-child td { border-bottom: none; }
tr.weak td { background: var(--warn-soft); }
pre.wrap { white-space: pre-wrap; word-break: break-word; background: var(--bg-soft); padding: 10px 12px; border-radius: 10px; font-size: .86rem; }

.answer-card h2 { display: flex; align-items: center; gap: 8px; }
.choice { display: flex; gap: 12px; align-items: flex-start; padding: 12px 14px; border: 1.5px solid var(--line); border-radius: 12px; margin: 8px 0;
  font-weight: 450; color: var(--fg); cursor: pointer; transition: border-color .12s, background .12s; }
.choice:hover { border-color: var(--accent-line); }
.choice:has(input:checked) { border-color: var(--accent); background: var(--accent-soft); }
.choice input { margin-top: 5px; } .choice p { margin: 0; }
.timer-bar { display: flex; align-items: center; gap: 14px; padding: 12px 16px; background: var(--bg-soft); border-radius: 12px; margin-bottom: 10px; }
.timer { font-size: 1.6rem; font-weight: 750; font-variant-numeric: tabular-nums; } .timer.over { color: var(--err); }
.submit-row { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; margin-top: 12px; }

.feedback { border-left: 5px solid var(--line-strong); }
.feedback.correct { border-left-color: var(--ok); } .feedback.partial { border-left-color: var(--warn); }
.feedback.wrong, .feedback.error { border-left-color: var(--err); } .feedback.pending { border-left-color: var(--accent); }
.feedback header { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; margin-bottom: 6px; }
.verdict { font-weight: 750; font-size: 1.05rem; text-transform: capitalize; }
.verdict.correct { color: var(--ok); } .verdict.partial { color: var(--warn); } .verdict.wrong { color: var(--err); }
.scorebig { font-weight: 750; padding: 2px 10px; border-radius: 999px; background: var(--bg-soft); }
.check { font-family: ui-monospace, Menlo, monospace; font-size: .86rem; background: var(--bg-soft); padding: 10px 12px; border-radius: 10px; margin: 8px 0; white-space: pre-wrap; }
.feedback details > summary, .help details > summary { color: var(--accent); font-weight: 550; font-size: .95rem; padding: 4px 0; }
.help details { border-top: 1px solid var(--line); padding: 10px 0; }
.help details:first-of-type { border-top: none; padding-top: 0; }
.help summary { display: flex; align-items: center; gap: 8px; }
.note { border-top: 1px dashed var(--line); padding-top: 10px; margin-top: 10px; }
.pager { position: sticky; bottom: 0; margin-top: 24px; padding: 14px 0; display: flex; justify-content: space-between; gap: 12px;
  background: linear-gradient(to top, var(--bg) 70%, transparent); }

/* --- auth -------------------------------------------------------------- */
.auth { max-width: 440px; margin: 7vh auto 0; text-align: center; }
.logo-big { width: 56px; height: 56px; border-radius: 16px; margin: 0 auto 14px; background: var(--accent); color: var(--accent-fg);
  display: grid; place-items: center; font-weight: 800; font-size: 1.4rem; }
.auth form { text-align: left; }

/* --- diagrams (inlined SVG from tools/diagrams.py, and Mermaid) ---------- */
figure.diagram { margin: 18px 0; padding: 14px; background: var(--card); border: 1px solid var(--line); border-radius: 14px; overflow-x: auto; }
figure.diagram figcaption { color: var(--muted); font-size: .86rem; text-align: center; margin-top: 8px; }
.d-svg { display: block; width: 100%; height: auto; min-width: 560px; font-family: ui-sans-serif, system-ui, sans-serif; }
.d-box { fill: var(--card); stroke: var(--line-strong); stroke-width: 1.4; }
.d-box.d-accent { fill: var(--accent-soft); stroke: var(--accent); }
.d-box.d-ok { fill: var(--ok-soft); stroke: var(--ok); }
.d-box.d-warn { fill: var(--warn-soft); stroke: var(--warn); }
.d-box.d-err { fill: var(--err-soft); stroke: var(--err); }
.d-box.d-ghost { fill: var(--bg-soft); stroke: var(--line-strong); stroke-dasharray: 5 4; }
.d-zone { fill: var(--bg-soft); fill-opacity: .55; stroke: var(--line-strong); stroke-dasharray: 6 5; stroke-width: 1.2; }
.d-zone.d-zone-ok { stroke: var(--ok); } .d-zone.d-zone-err { stroke: var(--err); }
.d-zl { fill: var(--muted); font-size: 12px; font-weight: 650; letter-spacing: .02em; }
.d-t { fill: var(--fg); font-size: 14px; font-weight: 650; }
.d-t.d-mono { font-family: ui-monospace, Menlo, monospace; font-size: 13px; }
.d-s { fill: var(--muted); font-size: 12px; }
.d-l { fill: var(--fg-soft); font-size: 12px; font-weight: 550; paint-order: stroke; stroke: var(--card); stroke-width: 4px; stroke-linejoin: round; }
.d-line { fill: none; stroke: var(--fg-soft); stroke-width: 1.6; }
.d-line.d-dash { stroke-dasharray: 5 4; stroke: var(--muted); }
.d-line.d-strong { stroke: var(--accent); stroke-width: 3; }
.d-head { fill: var(--fg-soft); }
.d-badge { fill: var(--accent); } .d-bt { fill: var(--accent-fg); font-size: 12px; font-weight: 750; }
pre.mermaid { background: none; text-align: center; margin: 0; color: var(--muted); font-size: .8rem; white-space: pre-wrap; }

@media (max-width: 600px) {
  .top-in { flex-wrap: wrap; gap: 8px; } .who .name { display: none; }
  main { padding: 16px 14px 56px; }
  .learn-box { flex-direction: column; }
  .module { padding-left: 0; } .module .num, .module::before { display: none; }
  .module summary { grid-template-columns: 1fr; }
}
.mt { margin-top: 10px; } .row.center { justify-content: center; }
.center-col { text-align: center; } .center-col form { margin-top: 8px; } .pad { padding: 0 20px 14px; }
.skillbar { width: 140px; flex: none; } .nowrap { white-space: nowrap; }
@media (max-width: 600px) { .skillbar { width: 70px; } }
main > * + * { margin-top: 16px; }
@media (max-width: 600px) {
  .brand { order: 1; } .who { order: 2; margin-left: auto; }
  .nav { order: 3; flex: 0 0 100%; flex-wrap: nowrap; overflow-x: auto; scrollbar-width: none; }
  .nav a { flex: none; }
}