/* AlpineTutor course shell.
   Palette deliberately matches the public site, so the free topics and the paid
   courses read as one product rather than two. */

:root {
  --ink: #1c1a17;
  --muted: #5f594f;
  --faint: #8a8580;
  --blue: #0b4f6c;
  --teal: #0f766e;
  --orange: #c2410c;
  --paper: #faf9f7;
  --card: #ffffff;
  --line: #e4e0d9;
  --sidebar: #1c1a17;
  --radius: 10px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 1.5rem; }

body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, "Segoe UI", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

code {
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.9em;
  background: rgba(15, 118, 110, 0.10);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

/* ---------- layout ---------- */

.shell {
  display: grid;
  grid-template-columns: 17rem 1fr;
  min-height: 100vh;
}

.sidebar {
  background: var(--sidebar);
  color: #f3f0eb;
  padding: 1.75rem 1.25rem;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
}

.brand { margin-bottom: 1.5rem; }
.brand strong { display: block; font-size: 1.05rem; }
.brand span { display: block; color: #a8a29e; font-size: 0.85rem; margin-top: 0.15rem; }

.nav { display: flex; flex-direction: column; gap: 0.1rem; }
.nav a {
  color: #d6d3d1;
  text-decoration: none;
  padding: 0.45rem 0.7rem;
  border-radius: 6px;
  font-size: 0.9rem;
  line-height: 1.35;
}
.nav a:hover { background: rgba(255, 255, 255, 0.08); color: #fff; }
.nav a.is-active { background: rgba(255, 255, 255, 0.14); color: #fff; font-weight: 600; }

.progress { margin-top: 1.75rem; border-top: 1px solid rgba(255,255,255,0.15); padding-top: 1rem; }
.progress label { display: flex; justify-content: space-between; font-size: 0.82rem; color: #a8a29e; margin-bottom: 0.4rem; }
.progress strong { color: #fff; }
.progress progress { width: 100%; height: 6px; border: 0; border-radius: 99px; background: rgba(255,255,255,0.15); }
.progress progress::-webkit-progress-bar { background: rgba(255,255,255,0.15); border-radius: 99px; }
.progress progress::-webkit-progress-value { background: var(--teal); border-radius: 99px; }
.progress progress::-moz-progress-bar { background: var(--teal); border-radius: 99px; }

main { min-width: 0; padding: 2.5rem 3rem 5rem; }

/* ---------- hero ---------- */

.hero { max-width: 54rem; margin-bottom: 2.5rem; }
.kicker {
  font-size: 0.78rem; font-weight: 700; letter-spacing: 0.09em;
  text-transform: uppercase; color: var(--teal); margin: 0 0 0.5rem;
}
.hero h1 { font-size: 2.1rem; line-height: 1.2; margin: 0 0 0.9rem; letter-spacing: -0.01em; }
.lede { font-size: 1.08rem; color: var(--muted); margin: 0 0 1.25rem; }

.stats { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.stats span {
  font-size: 0.8rem; color: var(--muted);
  background: var(--card); border: 1px solid var(--line);
  padding: 0.3rem 0.65rem; border-radius: 99px;
}

/* ---------- content ---------- */

.content { max-width: 54rem; }

section {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.75rem 2rem;
  margin-bottom: 1.5rem;
}

section h2 { font-size: 1.45rem; margin: 0 0 1rem; letter-spacing: -0.01em; }
section h3 { font-size: 1.08rem; margin: 1.75rem 0 0.6rem; }
section h3:first-of-type { margin-top: 1.25rem; }
section p { margin: 0 0 1rem; }
section ul, section ol { margin: 0 0 1rem; padding-left: 1.3rem; }
section li { margin-bottom: 0.45rem; }

/* ---------- panels ---------- */

.callout, .warning, .danger, .task {
  border-left: 4px solid;
  border-radius: 0 6px 6px 0;
  padding: 0.9rem 1.1rem;
  margin: 1.25rem 0;
  font-size: 0.96rem;
}
.callout { border-color: var(--teal); background: rgba(15, 118, 110, 0.07); }
.warning { border-color: #ca8a04; background: rgba(202, 138, 4, 0.08); }
.danger  { border-color: var(--orange); background: rgba(194, 65, 12, 0.07); }
.task    { border-color: var(--blue); background: rgba(11, 79, 108, 0.07); }

.grid-two { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin: 1.25rem 0; }
.card {
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1rem 1.15rem;
}
.card h3 { margin: 0 0 0.5rem; font-size: 0.98rem; }
.card p { margin: 0; font-size: 0.94rem; color: var(--muted); }

/* ---------- tables ---------- */

.table-wrap { overflow-x: auto; margin: 1.25rem 0; }
table { border-collapse: collapse; width: 100%; font-size: 0.9rem; }
thead th {
  text-align: left; background: var(--paper);
  border-bottom: 2px solid var(--line);
  padding: 0.6rem 0.75rem; font-size: 0.78rem;
  text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted);
}
tbody td { border-bottom: 1px solid var(--line); padding: 0.6rem 0.75rem; vertical-align: top; }
tbody tr:last-child td { border-bottom: 0; }
tbody td:first-child { font-weight: 600; }

/* ---------- exercises ---------- */

details {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  margin: 0.75rem 0 1.5rem;
  background: var(--paper);
}
details summary { cursor: pointer; font-weight: 600; color: var(--blue); }
details[open] summary { margin-bottom: 0.75rem; border-bottom: 1px solid var(--line); padding-bottom: 0.6rem; }
details p { margin: 0.75rem 0 0; font-size: 0.95rem; }

.checklist { margin: 1.25rem 0 0; padding-top: 1rem; border-top: 1px dashed var(--line); }
.checklist label {
  display: flex; gap: 0.6rem; align-items: flex-start;
  font-size: 0.92rem; color: var(--muted); cursor: pointer;
}
.checklist input { margin-top: 0.3rem; accent-color: var(--teal); flex-shrink: 0; }

/* ---------- module / course cards ---------- */

.module-list { display: grid; gap: 0.85rem; margin: 1.25rem 0; }
.module-list a {
  display: block; text-decoration: none; color: inherit;
  border: 1px solid var(--line); border-radius: 8px;
  padding: 1rem 1.2rem; background: var(--paper);
}
.module-list a:hover { border-color: var(--teal); background: #fff; }
.module-list .n { font-size: 0.75rem; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--teal); }
.module-list strong { display: block; font-size: 1.02rem; margin: 0.2rem 0 0.3rem; }
.module-list p { margin: 0; font-size: 0.9rem; color: var(--muted); }

.pager { display: flex; justify-content: space-between; gap: 1rem; margin-top: 2rem; }
.pager a {
  flex: 1; text-decoration: none; color: var(--blue); font-weight: 600; font-size: 0.93rem;
  border: 1px solid var(--line); border-radius: 8px; padding: 0.8rem 1rem; background: var(--card);
}
.pager a:hover { border-color: var(--teal); }
.pager a.next { text-align: right; }
.pager span { display: block; font-size: 0.75rem; color: var(--faint); font-weight: 400; text-transform: uppercase; letter-spacing: 0.06em; }

/* ---------- responsive ---------- */

@media (max-width: 62rem) {
  .shell { grid-template-columns: 1fr; }
  .sidebar { position: static; height: auto; }
  .nav { display: grid; grid-template-columns: repeat(auto-fit, minmax(11rem, 1fr)); gap: 0.25rem; }
  main { padding: 1.75rem 1.25rem 4rem; }
  .grid-two { grid-template-columns: 1fr; }
  section { padding: 1.35rem 1.25rem; }
  .hero h1 { font-size: 1.65rem; }
}

@media print {
  .sidebar, .pager { display: none; }
  .shell { display: block; }
  section { break-inside: avoid; border: 0; padding: 0; margin-bottom: 1.5rem; }
  details { break-inside: avoid; }
  details summary { display: none; }
}

/* ---------- assessment ---------- */

.quiz-intro { color: var(--muted); margin: 0 0 1.25rem; }

.quiz-q {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 1rem 1.15rem;
  margin: 0 0 1rem;
  background: var(--paper);
}
.quiz-q legend { font-weight: 600; padding: 0 0.4rem; display: flex; gap: 0.5rem; align-items: baseline; }
.quiz-n {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 1.5rem; height: 1.5rem; border-radius: 99px;
  background: var(--teal); color: #fff; font-size: 0.78rem; flex-shrink: 0;
}

.quiz-opt {
  display: flex; gap: 0.6rem; align-items: flex-start;
  padding: 0.5rem 0.6rem; border-radius: 6px; cursor: pointer;
  font-size: 0.95rem;
}
.quiz-opt:hover { background: rgba(15, 118, 110, 0.06); }
.quiz-opt input { margin-top: 0.3rem; accent-color: var(--teal); flex-shrink: 0; }
.quiz-opt.is-correct { background: rgba(15, 118, 110, 0.12); font-weight: 600; }
.quiz-opt.is-wrong { background: rgba(194, 65, 12, 0.10); text-decoration: line-through; }

.quiz-explain {
  margin: 0.75rem 0 0; padding: 0.7rem 0.9rem;
  border-left: 3px solid var(--teal); background: rgba(15, 118, 110, 0.06);
  font-size: 0.92rem; color: var(--muted); border-radius: 0 6px 6px 0;
}

.quiz-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; align-items: center; margin-top: 1.25rem; }
.quiz-submit, .quiz-reset {
  font: inherit; font-weight: 600; cursor: pointer;
  border: 1px solid var(--teal); border-radius: 6px;
  padding: 0.55rem 1.1rem; background: var(--teal); color: #fff;
}
.quiz-reset { background: transparent; color: var(--teal); }
.quiz-submit:hover, .quiz-reset:hover { filter: brightness(1.08); }

.quiz-result { margin: 0; font-weight: 600; font-size: 0.95rem; }
.quiz-result.is-pass { color: var(--teal); }
.quiz-result.is-fail { color: var(--orange); }
.quiz-result.is-warn { color: #a16207; }

@media print {
  .quiz-actions, .quiz-opt input { display: none; }
  .quiz-explain { display: block !important; }
}

/* Preformatted blocks carry tag diagrams and formulae that must not be rewrapped,
   so they scroll rather than break the page — the same treatment as wide tables. */
pre {
  overflow-x: auto;
  background: var(--paper);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.9rem 1.1rem;
  margin: 1.25rem 0;
  font-size: 0.88rem;
  line-height: 1.5;
}
pre code {
  background: none;
  padding: 0;
  white-space: pre;
}