/* Learn: mobile-first dashboard look. Tiles and panels, readable on an Android phone. */
:root {
  --bg: #f4f5f7; --panel: #ffffff; --ink: #1d2330; --muted: #5d6676; --line: #dde1e8;
  --accent: #2457c5; --accent-ink: #ffffff; --good: #1d7a46; --good-bg: #e3f4ea;
  --bad: #b3261e; --bad-bg: #fbe9e7; --warn: #8a5a00; --warn-bg: #fff4d6; --code-bg: #f0f2f6;
  --radius: 12px;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12151b; --panel: #1b2029; --ink: #e7eaf0; --muted: #9aa3b2; --line: #2c3340;
    --accent: #6f9bff; --accent-ink: #0d1117; --good: #6fd39a; --good-bg: #16301f;
    --bad: #ff8a80; --bad-bg: #3a1a18; --warn: #ffd166; --warn-bg: #3a2f10; --code-bg: #232a35;
  }
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; background: var(--bg); color: var(--ink);
  font: 17px/1.55 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
body.center { min-height: 100vh; display: grid; place-items: center; padding: 16px; }
a { color: var(--accent); }
h1 { font-size: 1.6rem; margin: 0.4rem 0 1rem; }
h2 { font-size: 1.2rem; margin: 0 0 0.6rem; }
.h3 { font-size: 1.05rem; }
code, pre, textarea.code, input.code { font-family: ui-monospace, "Cascadia Code", Consolas, monospace; font-size: 0.95rem; }

.top { position: sticky; top: 0; z-index: 5; display: flex; flex-wrap: wrap; align-items: center; gap: 4px 12px;
  padding: 8px 16px; background: var(--panel); border-bottom: 1px solid var(--line); }
.brand { font-weight: 700; text-decoration: none; color: var(--ink); }
.tabs { display: flex; gap: 2px; overflow-x: auto; flex: 1 1 auto; order: 3; width: 100%; }
.tabs a { padding: 8px 12px; border-radius: 8px; text-decoration: none; color: var(--muted); white-space: nowrap; }
.tabs a[aria-current="page"] { background: var(--accent); color: var(--accent-ink); }
.logout { margin-left: auto; }
button.link { background: none; border: 0; color: var(--muted); text-decoration: underline; padding: 6px; }
@media (min-width: 760px) { .tabs { order: 0; width: auto; } }

.wrap { max-width: 920px; margin: 0 auto; padding: 16px; }
.panel { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin: 0 0 16px; }
.login { width: min(380px, 100%); }
.tiles { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; margin-bottom: 16px; }
.tile { display: flex; flex-direction: column; gap: 4px; background: var(--panel); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 14px; text-decoration: none; color: var(--ink); min-height: 110px; }
.tile-hot { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent) inset; }
.tile-label { font-size: 0.85rem; color: var(--muted); font-weight: 600; }
.tile-num { font-size: 2rem; font-weight: 700; line-height: 1.1; }
.tile-num.small { font-size: 1.4rem; }
.tile-sub { font-size: 0.9rem; color: var(--muted); }

.muted { color: var(--muted); }
.small { font-size: 0.88rem; }
.good { color: var(--good); }
.bad { color: var(--bad); }
.warn { background: var(--warn-bg); color: var(--warn); padding: 8px 12px; border-radius: 8px; }
.chip { display: inline-block; padding: 2px 8px; border-radius: 999px; font-size: 0.8rem; background: var(--code-bg); color: var(--muted); vertical-align: middle; }
.chip-good { background: var(--good-bg); color: var(--good); }
.chip-bad { background: var(--bad-bg); color: var(--bad); }
.chip-go { background: var(--accent); color: var(--accent-ink); }
.chip-dim { opacity: 0.8; }
.crumb { font-size: 0.9rem; color: var(--muted); margin: 0; }

button, select, input, textarea { font: inherit; }
button { min-height: 44px; padding: 8px 14px; border-radius: 10px; border: 1px solid var(--line);
  background: var(--panel); color: var(--ink); cursor: pointer; }
button.primary { background: var(--accent); color: var(--accent-ink); border-color: var(--accent); font-weight: 600; }
button:disabled { opacity: 0.55; cursor: default; }
input[type="text"], input[type="password"], select, textarea { width: 100%; padding: 10px; border-radius: 10px;
  border: 1px solid var(--line); background: var(--panel); color: var(--ink); }
label { display: block; font-weight: 600; margin: 10px 0 4px; }
.row { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.stack button { margin-top: 12px; }

.prose p, .prose li { max-width: 68ch; }
.prose table { display: block; overflow-x: auto; border-collapse: collapse; margin: 12px 0; max-width: 100%; }
.prose th, .prose td { border: 1px solid var(--line); padding: 6px 10px; text-align: left; vertical-align: top; }
.prose th { background: var(--bg); }
.prose code, .card code { background: var(--code-bg); padding: 1px 5px; border-radius: 5px; }
.personal-block { border-left: 4px solid var(--warn); background: var(--warn-bg); padding: 4px 12px; border-radius: 6px; margin: 12px 0; }
.tag-outside { font-size: 0.9rem; background: var(--warn-bg); color: var(--warn); padding: 6px 10px; border-radius: 8px; }
.embed { position: relative; aspect-ratio: 16 / 9; }
.embed iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; border-radius: 10px; }
video { width: 100%; border-radius: 10px; background: #000; }
.transcript { white-space: pre-wrap; }

.example { border: 1px solid var(--line); border-radius: 10px; padding: 10px; margin: 14px 0; background: var(--bg); }
.example-head { display: flex; justify-content: space-between; gap: 8px; font-weight: 600; flex-wrap: wrap; }
textarea.code { background: var(--code-bg); white-space: pre; overflow-x: auto; tab-size: 4; }
pre { overflow-x: auto; }
pre.out, pre.verified, pre.code-view { background: var(--code-bg); padding: 10px; border-radius: 8px; margin: 8px 0; white-space: pre-wrap; }
pre.verified::before { content: "Verified output"; display: block; font-family: system-ui, sans-serif; font-size: 0.8rem; color: var(--good); }

.card-slot + .card-slot { margin-top: 14px; }
.card { border: 1px solid var(--line); border-radius: 10px; padding: 12px; }
.card-type { font-size: 0.8rem; font-weight: 700; color: var(--accent); text-transform: uppercase; letter-spacing: 0.03em; }
.card-prompt { margin: 6px 0; }
.pick-lines { list-style: none; padding: 0; margin: 8px 0; }
.line-pick { width: 100%; text-align: left; font-family: ui-monospace, Consolas, monospace; margin: 3px 0; white-space: pre-wrap; }
.line-pick.picked { border-color: var(--accent); box-shadow: 0 0 0 2px var(--accent) inset; }
.parsons { list-style: none; padding: 0; margin: 8px 0; }
.parsons li { display: flex; align-items: center; gap: 8px; padding: 6px; margin: 6px 0; border: 1px solid var(--line);
  border-radius: 8px; background: var(--panel); user-select: none; }
.parsons li code { flex: 1; white-space: pre; overflow-x: auto; }
.parsons li.dragging { opacity: 0.6; border-color: var(--accent); }
.handle { touch-action: none; cursor: grab; padding: 10px 8px; font-weight: 700; color: var(--muted); }
.nudge { min-height: 36px; padding: 4px 8px; font-size: 0.85rem; }
.feedback pre { margin: 4px 0; }

.tests { list-style: none; padding: 0; font-family: ui-monospace, Consolas, monospace; font-size: 0.9rem; }
.chat { max-height: 360px; overflow-y: auto; margin: 10px 0; display: flex; flex-direction: column; gap: 8px; }
.msg { padding: 8px 12px; border-radius: 10px; max-width: 90%; }
.msg p { margin: 0; white-space: pre-wrap; }
.msg-me { align-self: flex-end; background: var(--accent); color: var(--accent-ink); }
.msg-tutor { align-self: flex-start; background: var(--code-bg); }
.msg.hint { border-left: 4px solid var(--warn); }

.stage summary { cursor: pointer; list-style: none; }
.stage summary h2 { display: inline; }
.modules { display: grid; gap: 10px; margin-top: 10px; }
.module { border: 1px solid var(--line); border-radius: 10px; padding: 10px; }
.module-head { display: flex; flex-wrap: wrap; gap: 6px 10px; align-items: center; }
.module-id { font-weight: 700; }
.module-title { flex: 1 1 200px; }
.lesson-list { list-style: none; padding: 0; margin: 6px 0 0; }
.lesson-list li { display: flex; justify-content: space-between; gap: 8px; padding: 4px 0; border-top: 1px dashed var(--line); font-size: 0.92rem; }
.lesson-list .state { color: var(--muted); font-size: 0.82rem; white-space: nowrap; }
.lesson-done .state { color: var(--good); }
.lesson-failed-checks .state { color: var(--bad); }

.table { width: 100%; border-collapse: collapse; font-size: 0.92rem; display: block; overflow-x: auto; }
.table th, .table td { text-align: left; padding: 6px 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
.explain { border-top: 1px solid var(--line); padding: 8px 0; }
.explain p { margin: 4px 0; white-space: pre-wrap; }