/* Kubernetes Beyond YAML — lesson app.
   Shares the palette with the guidebook (course.css) so the two read as one product. */

:root {
  color-scheme: light dark;
  --ink: #172033;
  --muted: #5d677b;
  --paper: #f2f5fa;
  --panel: #ffffff;
  --line: #d9deea;
  --line-strong: #c2cbdd;
  --navy: #172554;
  --blue: #326ce5;
  --blue-dark: #2456bd;
  --cyan: #0891b2;
  --good: #15803d;
  --good-bg: #dcfce7;
  --good-line: #86d9a4;
  --bad: #b91c1c;
  --bad-bg: #fee2e2;
  --bad-line: #f2a5a5;
  --amber: #b45309;
  --amber-bg: #fef3c7;
  --shadow: 0 10px 32px #18264d12;
  --radius: 16px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #e9eef9; --muted: #a6b2c8; --paper: #0b111d; --panel: #151e2e;
    --line: #2c3a50; --line-strong: #3b4c68; --navy: #0f1c3f;
    --good-bg: #103322; --good-line: #2f7a4f;
    --bad-bg: #3a1516; --bad-line: #8c3a3a;
    --amber-bg: #40300f;
    --shadow: 0 10px 32px #0006;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16px/1.6 ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  -webkit-text-size-adjust: 100%;
}
a { color: var(--blue); }
code {
  padding: 1px 5px; border-radius: 5px;
  background: #326ce514; font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: .92em;
}
h1, h2, h3 { letter-spacing: -.02em; line-height: 1.18; }
:focus-visible { outline: 3px solid var(--blue); outline-offset: 2px; }
[hidden] { display: none !important; }

/* ---------- chrome ---------- */

.topbar {
  position: sticky; top: 0; z-index: 20;
  display: flex; align-items: center; gap: 10px;
  padding: 10px clamp(14px, 4vw, 28px);
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 88%, transparent);
  backdrop-filter: blur(10px);
}
.topbar .mark { margin-right: auto; font-weight: 800; font-size: .95rem; letter-spacing: -.01em; }
.topbar .mark span { display: block; color: var(--muted); font-size: .72rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; }
.stat {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 6px 11px; border: 1px solid var(--line); border-radius: 999px;
  background: var(--panel); font-size: .85rem; font-weight: 750; white-space: nowrap;
}
.stat b { font-variant-numeric: tabular-nums; }
.stat.due { border-color: var(--amber); color: var(--amber); background: var(--amber-bg); }
button.stat { cursor: pointer; color: inherit; }
button.stat:hover { border-color: var(--line-strong); }
.stat.sync { min-width: 34px; justify-content: center; color: var(--muted); cursor: help; }

.wrap { width: min(760px, 100%); margin: 0 auto; padding: 26px clamp(14px, 4vw, 24px) 120px; }

/* ---------- buttons ---------- */

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 13px 22px; border: 0; border-radius: 14px;
  box-shadow: inset 0 -4px 0 #0003;
  background: var(--blue); color: #fff;
  font: inherit; font-weight: 800; letter-spacing: .01em; cursor: pointer;
  transition: transform .06s, filter .12s;
}
.btn:hover { filter: brightness(1.06); }
.btn:active { transform: translateY(2px); box-shadow: inset 0 -2px 0 #0003; }
.btn:disabled { opacity: .45; cursor: not-allowed; box-shadow: inset 0 -4px 0 #0002; }
.btn.good { background: var(--good); }
.btn.bad { background: var(--bad); }
.btn.ghost { background: transparent; color: var(--muted); box-shadow: none; border: 2px solid var(--line); }
.btn.ghost:hover { color: var(--ink); border-color: var(--line-strong); filter: none; }
.btn.wide { width: 100%; }

/* ---------- path ---------- */

.hero {
  padding: clamp(22px, 4vw, 34px); margin-bottom: 26px;
  border-radius: 22px; color: #fff;
  background: linear-gradient(135deg, #172554 0%, #244ea5 62%, #0891b2 100%);
  box-shadow: var(--shadow);
}
.hero h1 { margin: 6px 0 10px; font-size: clamp(1.7rem, 4.4vw, 2.6rem); }
.hero p { max-width: 52ch; margin: 0 0 18px; color: #dbe7ff; }
.hero .eyebrow { color: #8fdcff; font-size: .7rem; font-weight: 800; letter-spacing: .14em; text-transform: uppercase; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 10px; }
.hero .btn { background: #fff; color: #14306b; }
.hero .btn.ghost { background: #ffffff1a; color: #eaf2ff; border-color: #ffffff40; }

.overall { display: flex; align-items: center; gap: 12px; margin: 0 0 18px; }
.bar { flex: 1; height: 12px; overflow: hidden; border-radius: 99px; background: var(--line); }
.bar > i { display: block; height: 100%; width: 0; border-radius: 99px; background: linear-gradient(90deg, var(--blue), var(--cyan)); transition: width .35s; }
.overall small { color: var(--muted); font-weight: 750; font-variant-numeric: tabular-nums; }

.unit {
  position: relative; margin: 0 0 14px; padding: 18px;
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--panel); box-shadow: var(--shadow);
}
.unit.locked { opacity: .72; }
.unit-head { display: flex; align-items: flex-start; gap: 14px; }
.badge {
  display: grid; place-items: center; flex: 0 0 auto;
  width: 46px; height: 46px; border-radius: 14px;
  background: var(--blue); color: #fff; font-weight: 800; font-size: 1.05rem;
  box-shadow: inset 0 -3px 0 #0003;
}
.unit.done .badge { background: var(--good); }
.unit.locked .badge { background: var(--line-strong); color: var(--muted); }
.unit-head h2 { margin: 0; font-size: 1.16rem; }
.unit-head .tag { color: var(--muted); font-size: .7rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.unit-head p { margin: 5px 0 0; color: var(--muted); font-size: .92rem; }
.unit-meta { display: flex; align-items: center; gap: 10px; margin-left: auto; }
.ring { font-size: .8rem; font-weight: 800; color: var(--muted); font-variant-numeric: tabular-nums; white-space: nowrap; }

.lessons { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 14px; }
.node {
  display: flex; align-items: center; gap: 10px;
  padding: 11px 15px 11px 11px; border: 2px solid var(--line); border-radius: 14px;
  background: var(--paper); color: inherit; font: inherit; font-weight: 750; text-align: left; cursor: pointer;
  transition: border-color .12s, transform .06s;
}
.node:hover { border-color: var(--blue); }
.node:active { transform: translateY(1px); }
.node .dot {
  display: grid; place-items: center; width: 30px; height: 30px; flex: 0 0 auto;
  border-radius: 50%; background: var(--line); color: var(--muted); font-size: .82rem; font-weight: 800;
}
.node.done { border-color: var(--good-line); background: var(--good-bg); }
.node.done .dot { background: var(--good); color: #fff; }
.node small { display: block; color: var(--muted); font-weight: 600; font-size: .76rem; }
.guide-link { display: inline-block; margin-top: 12px; font-size: .85rem; font-weight: 750; }

/* ---------- lesson ---------- */

.lessonbar { display: flex; align-items: center; gap: 12px; margin-bottom: 22px; }
.lessonbar .bar { height: 14px; }
.lessonbar .bar > i { background: linear-gradient(90deg, var(--good), #34d399); }
.iconbtn {
  display: grid; place-items: center; width: 36px; height: 36px; flex: 0 0 auto;
  border: 0; border-radius: 10px; background: transparent; color: var(--muted);
  font-size: 1.25rem; line-height: 1; cursor: pointer;
}
.iconbtn:hover { background: var(--line); color: var(--ink); }

.kicker { color: var(--muted); font-size: .72rem; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }
.lesson-name { margin-bottom: 18px; padding-bottom: 10px; border-bottom: 1px solid var(--line); color: var(--blue); }
.prompt { margin: 8px 0 20px; font-size: clamp(1.2rem, 3.2vw, 1.55rem); font-weight: 800; }
.prompt code { font-size: .88em; }

.opts { display: grid; gap: 10px; }
.opt {
  display: flex; align-items: center; gap: 12px; width: 100%;
  padding: 14px 16px; border: 2px solid var(--line); border-radius: 14px;
  background: var(--panel); color: inherit; font: inherit; text-align: left; cursor: pointer;
  box-shadow: inset 0 -3px 0 #0000000a;
  transition: border-color .12s, background .12s, transform .06s;
}
.opt:hover { border-color: var(--line-strong); }
.opt:active { transform: translateY(1px); }
.opt .key {
  display: grid; place-items: center; width: 26px; height: 26px; flex: 0 0 auto;
  border: 1px solid var(--line); border-radius: 7px;
  color: var(--muted); font-size: .78rem; font-weight: 800;
}
.opt[aria-pressed="true"] { border-color: var(--blue); background: #326ce50f; }
.opt[aria-pressed="true"] .key { border-color: var(--blue); background: var(--blue); color: #fff; }
.opt.right { border-color: var(--good-line); background: var(--good-bg); }
.opt.wrong { border-color: var(--bad-line); background: var(--bad-bg); }
.opt.locked { pointer-events: none; }

/* chips: order + cloze */
.slots {
  display: flex; flex-wrap: wrap; align-content: flex-start; gap: 8px;
  min-height: 62px; padding: 12px;
  border: 2px dashed var(--line); border-radius: 14px; background: var(--panel);
}
.slots:empty::after { content: attr(data-empty); color: var(--muted); font-size: .9rem; }
.bank { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.chip {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 9px 13px; border: 2px solid var(--line); border-radius: 11px;
  background: var(--panel); color: inherit; font: inherit; font-weight: 700; cursor: pointer;
  box-shadow: inset 0 -3px 0 #0000000a;
}
.chip:hover { border-color: var(--line-strong); }
.chip .n { color: var(--muted); font-size: .74rem; font-weight: 800; font-variant-numeric: tabular-nums; }
.chip.used { opacity: .3; pointer-events: none; }
.chip.right { border-color: var(--good-line); background: var(--good-bg); }
.chip.wrong { border-color: var(--bad-line); background: var(--bad-bg); }
.cloze-line { margin: 0 0 16px; font-size: 1.1rem; line-height: 1.9; }
.blank {
  display: inline-block; min-width: 130px; padding: 2px 12px; margin: 0 2px;
  border: 0; border-bottom: 3px solid var(--blue); border-radius: 4px;
  background: #326ce512; color: inherit; font: inherit; font-weight: 800; cursor: pointer;
}
.blank.empty { color: var(--muted); font-weight: 600; }
.blank.right { border-bottom-color: var(--good); background: var(--good-bg); }
.blank.wrong { border-bottom-color: var(--bad); background: var(--bad-bg); }

/* recall */
.recall-in {
  width: 100%; min-height: 118px; padding: 14px;
  border: 2px solid var(--line); border-radius: 14px;
  background: var(--panel); color: inherit; font: inherit; resize: vertical;
}
.recall-in::placeholder { color: var(--muted); }
.model { margin-top: 16px; padding: 16px 18px; border-left: 5px solid var(--good); border-radius: 0 12px 12px 0; background: var(--good-bg); }
.model h4 { margin: 0 0 8px; font-size: .74rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; color: var(--good); }
.model ul { margin: 0 0 12px; padding-left: 1.15rem; }
.model li { margin: 4px 0; }
.model p { margin: 0; }
.selfgrade { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 16px; }

/* teach card */
.teach { padding: 22px; border: 1px solid var(--line); border-left: 5px solid var(--blue); border-radius: 0 var(--radius) var(--radius) 0; background: var(--panel); box-shadow: var(--shadow); }
.teach h3 { margin: 6px 0 12px; font-size: clamp(1.25rem, 3.4vw, 1.6rem); }
.teach p { margin: 0; color: var(--ink); font-size: 1.02rem; }
.teach .note { margin-top: 14px; padding: 12px 14px; border-radius: 10px; background: var(--amber-bg); color: var(--amber); font-size: .92rem; font-weight: 650; }
.flowstrip { display: flex; flex-wrap: wrap; gap: 8px 0; margin: 18px 0 0; padding-bottom: 6px; }
.flowstrip div {
  flex: 0 1 auto; max-width: 100%; padding: 10px 12px;
  border: 1px solid var(--line); border-radius: 10px; background: var(--paper);
  font-size: .84rem; font-weight: 700; text-align: center;
}
.flowstrip div + div { position: relative; margin-left: 26px; }
.flowstrip div + div::before { position: absolute; left: -17px; top: 50%; transform: translateY(-50%); content: "→"; color: var(--blue); font-weight: 900; }

.clip {
  display: inline-flex; align-items: center; gap: 9px; margin-top: 16px;
  padding: 10px 14px; border: 1px solid var(--line); border-radius: 11px;
  background: var(--paper); color: inherit; font-size: .88rem; font-weight: 700; text-decoration: none;
}
.clip:hover { border-color: var(--blue); }
.clip .play { display: grid; place-items: center; width: 26px; height: 26px; flex: 0 0 auto; border-radius: 50%; background: #e11d48; color: #fff; font-size: .62rem; }
.clip small { display: block; color: var(--muted); font-weight: 600; }

/* ---------- fixed primary action ---------- */

.checkbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 25;
  border-top: 1px solid var(--line);
  background: color-mix(in srgb, var(--panel) 92%, transparent);
  backdrop-filter: blur(10px);
}
.checkbar-inner { width: min(760px, 100%); margin: 0 auto; padding: 14px clamp(14px, 4vw, 24px); }

/* ---------- feedback ---------- */

.feedback {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 30;
  border-top: 2px solid var(--line);
  background: var(--panel);
  transform: translateY(102%); transition: transform .22s ease-out;
}
.feedback.up { transform: none; }
.feedback.ok { border-top-color: var(--good-line); background: var(--good-bg); }
.feedback.no { border-top-color: var(--bad-line); background: var(--bad-bg); }
.feedback .inner { display: flex; align-items: flex-start; gap: 16px; width: min(760px, 100%); margin: 0 auto; padding: 16px clamp(14px, 4vw, 24px); }
.feedback .body { flex: 1; min-width: 0; }
.feedback h4 { margin: 0 0 6px; font-size: 1.05rem; }
.feedback.ok h4 { color: var(--good); }
.feedback.no h4 { color: var(--bad); }
.feedback p { margin: 0; font-size: .95rem; }
.feedback .links { display: flex; flex-wrap: wrap; gap: 8px 16px; margin-top: 10px; font-size: .85rem; font-weight: 750; }
.feedback .btn { flex: 0 0 auto; align-self: center; }
@media (max-width: 620px) {
  .feedback .inner { flex-direction: column; gap: 12px; }
  .feedback .btn { width: 100%; }
}

/* ---------- summary ---------- */

.summary { text-align: center; padding-top: 18px; }
.summary .big { font-size: clamp(2rem, 7vw, 3rem); font-weight: 800; margin: 8px 0 4px; }
.summary .sub { color: var(--muted); margin: 0 0 26px; }
.tiles { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-bottom: 26px; }
.tile { padding: 16px 12px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); }
.tile b { display: block; font-size: 1.5rem; font-variant-numeric: tabular-nums; }
.tile span { color: var(--muted); font-size: .78rem; font-weight: 750; }
.summary .btn { min-width: 220px; }
.summary .actions { display: flex; flex-direction: column; align-items: center; gap: 10px; }

.empty { padding: 40px 20px; text-align: center; color: var(--muted); }
.empty h2 { color: var(--ink); }

@media (max-width: 520px) {
  .topbar .mark span { display: none; }
  .unit-meta { width: 100%; margin: 10px 0 0; }
  .tiles { grid-template-columns: 1fr; }
}

/* ---------- module video: a step in the path, not a link off the site ---- */

.node.video { border-color: var(--blue); background: color-mix(in srgb, var(--blue) 7%, var(--paper)); }
.node.video .dot { background: var(--blue); color: #fff; }
.node.video.done .dot { background: var(--good); }

.module-view { max-width: 900px; margin: 0 auto; }
.module-view .back { margin-bottom: 14px; }
.module-view h1 { margin: 6px 0 4px; }
.module-sub { color: var(--muted); margin: 0 0 16px; line-height: 1.5; }

.module-player {
  width: 100%; max-width: 100%; aspect-ratio: 16 / 9; height: auto;
  display: block; border: 2px solid var(--line); border-radius: 14px;
  background: #000;
}

.module-parts-head { margin: 22px 0 8px; font-size: 1rem; }
.module-parts { margin: 0; padding-left: 22px; columns: 2; column-gap: 30px; }
.module-parts li { margin: 4px 0; break-inside: avoid; line-height: 1.45; }

.module-actions { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 22px; }

@media (max-width: 720px) {
  .module-parts { columns: 1; }
  .module-actions .btn { width: 100%; }
}

/* Classroom audio — a second way through a unit, not a step after the video.
 * Given its own hue so the path reads as two parallel options rather than a
 * sequence, and the same done-state treatment as every other node. */
.node.listen { border-color: var(--violet, #a78bfa); background: color-mix(in srgb, var(--violet, #a78bfa) 7%, var(--paper)); }
.node.listen .dot { background: var(--violet, #a78bfa); color: #fff; }
.node.listen.done .dot { background: var(--good); }

.module-audio {
  width: 100%; display: block; margin: 0 0 4px;
  border: 2px solid var(--line); border-radius: 14px;
}

/* Watch/listen toggle. The players have very different heights, so the
 * switch sits under whichever is showing rather than between them. */
.module-switch { display: flex; gap: 8px; flex-wrap: wrap; margin: 12px 0 4px; }
.module-switch .btn.on {
  border-color: var(--blue);
  background: color-mix(in srgb, var(--blue) 12%, var(--paper));
  color: var(--ink);
}