/* ==========================================================================
   Shared stylesheet for the "learn-kid-walking" teaching workspace.
   Every lesson and reference document links this file.
   Tufte-influenced: generous measure, serif body, marginal notes, print-first.
   ========================================================================== */

:root {
  --paper:      #fffdf9;
  --ink:        #1a1814;
  --ink-soft:   #55504a;
  --ink-faint:  #8a8177;
  --rule:       #e2dcd1;
  --accent:     #8c3a1b;   /* burnt sienna — links, emphasis */
  --accent-bg:  #fdf3ec;
  --gate:       #2f5d50;   /* deep green — "do this" blocks */
  --gate-bg:    #eef4f1;
  --warn:       #7a5c12;
  --warn-bg:    #fbf5e4;
  --measure:    38rem;
  --margin-col: 15rem;
}

/* ---------- base ---------- */

html { font-size: 17px; }

body {
  margin: 0 auto;
  padding: 4rem 2rem 8rem;
  max-width: calc(var(--measure) + var(--margin-col) + 4rem);
  background: var(--paper);
  color: var(--ink);
  font-family: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  font-size: 1.05rem;
  line-height: 1.62;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

/* Body text lives in the left column; asides hang in the right margin. */
p, ul, ol, h1, h2, h3, h4, blockquote, table, .callout, .card, figure, hr, .quiz, .checklist, .ladder {
  max-width: var(--measure);
}

/* ---------- typography ---------- */

h1 {
  font-size: 2.15rem;
  line-height: 1.15;
  font-weight: 600;
  letter-spacing: -0.015em;
  margin: 0 0 0.4rem;
}

h2 {
  font-size: 1.4rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  margin: 3.2rem 0 0.8rem;
  padding-bottom: 0.3rem;
  border-bottom: 1px solid var(--rule);
}

h3 {
  font-size: 1.12rem;
  font-weight: 600;
  margin: 2rem 0 0.5rem;
}

p { margin: 0 0 1.1rem; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(140, 58, 27, 0.3);
}
a:hover { border-bottom-color: var(--accent); }

strong { font-weight: 650; }
em { font-style: italic; }

code, .mono {
  font-family: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  font-size: 0.88em;
  background: rgba(0, 0, 0, 0.045);
  padding: 0.1em 0.35em;
  border-radius: 3px;
}

hr {
  border: 0;
  border-top: 1px solid var(--rule);
  margin: 3rem 0;
}

/* ---------- masthead ---------- */

.masthead {
  margin-bottom: 3rem;
  padding-bottom: 1.4rem;
  border-bottom: 2px solid var(--ink);
  max-width: var(--measure);
}

.eyebrow {
  font-size: 0.74rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
  font-weight: 600;
  margin: 0 0 0.9rem;
}

.subtitle {
  font-size: 1.15rem;
  color: var(--ink-soft);
  font-style: italic;
  margin: 0.5rem 0 0;
}

.meta-line {
  font-size: 0.82rem;
  color: var(--ink-faint);
  margin-top: 1rem;
  letter-spacing: 0.02em;
}

/* ---------- marginal notes ---------- */

.sidenote {
  float: right;
  clear: right;
  width: var(--margin-col);
  margin-right: calc(-1 * var(--margin-col) - 2rem);
  margin-top: 0.3rem;
  margin-bottom: 1rem;
  font-size: 0.82rem;
  line-height: 1.5;
  color: var(--ink-soft);
  border-left: 2px solid var(--rule);
  padding-left: 0.9rem;
}
.sidenote strong { color: var(--ink); }

/* ---------- callouts ---------- */

.callout {
  margin: 1.8rem 0;
  padding: 1.1rem 1.3rem;
  border-left: 3px solid var(--accent);
  background: var(--accent-bg);
  border-radius: 0 4px 4px 0;
}
.callout > :last-child { margin-bottom: 0; }
.callout .label {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.callout.do    { border-left-color: var(--gate); background: var(--gate-bg); }
.callout.do .label { color: var(--gate); }

.callout.watch { border-left-color: var(--warn); background: var(--warn-bg); }
.callout.watch .label { color: var(--warn); }

/* ---------- the ladder component ---------- */

.ladder { margin: 1.8rem 0; padding: 0; list-style: none; counter-reset: rung; }

.ladder li {
  position: relative;
  padding: 0.85rem 0 0.85rem 3.1rem;
  border-bottom: 1px solid var(--rule);
  counter-increment: rung;
}
.ladder li:first-child { border-top: 1px solid var(--rule); }

.ladder li::before {
  content: counter(rung);
  position: absolute;
  left: 0;
  top: 0.85rem;
  width: 1.85rem;
  height: 1.85rem;
  line-height: 1.85rem;
  text-align: center;
  border-radius: 50%;
  background: var(--ink);
  color: var(--paper);
  font-size: 0.82rem;
  font-weight: 600;
  font-family: -apple-system, system-ui, sans-serif;
}

.ladder .rung-name { font-weight: 650; display: block; }
.ladder .rung-body { font-size: 0.94rem; color: var(--ink-soft); }

/* ---------- interactive checklist ---------- */

.checklist { margin: 1.6rem 0; padding: 0; list-style: none; }

.checklist li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.6rem 0;
  border-bottom: 1px dotted var(--rule);
}

.checklist input[type="checkbox"] {
  margin-top: 0.42rem;
  width: 1.05rem;
  height: 1.05rem;
  accent-color: var(--gate);
  flex: none;
  cursor: pointer;
}

.checklist label { cursor: pointer; }
.checklist input:checked + label { color: var(--ink-faint); text-decoration: line-through; }

/* ---------- quiz (see quiz.js) ---------- */

.quiz {
  margin: 2rem 0;
  padding: 1.4rem 1.5rem;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: #fff;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.03);
}

.quiz .q-num {
  font-size: 0.72rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  color: var(--ink-faint);
  font-weight: 700;
}

.quiz .q-text { font-weight: 600; margin: 0.4rem 0 1rem; }

.quiz .options { display: flex; flex-direction: column; gap: 0.5rem; }

.quiz button.opt {
  font-family: inherit;
  font-size: 0.97rem;
  text-align: left;
  padding: 0.7rem 0.9rem;
  border: 1px solid var(--rule);
  border-radius: 4px;
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
  transition: background 0.12s, border-color 0.12s;
}
.quiz button.opt:hover:not(:disabled) { background: #f6f1e8; border-color: var(--ink-faint); }
.quiz button.opt:disabled { cursor: default; }
.quiz button.opt.correct { background: var(--gate-bg); border-color: var(--gate); font-weight: 600; }
.quiz button.opt.wrong   { background: #fbeceb; border-color: #b4483a; }

.quiz .feedback {
  margin-top: 1rem;
  padding-top: 0.9rem;
  border-top: 1px solid var(--rule);
  font-size: 0.94rem;
  color: var(--ink-soft);
  display: none;
}
.quiz .feedback.shown { display: block; }
.quiz .feedback b { color: var(--ink); }

.quiz-score {
  font-size: 0.88rem;
  color: var(--ink-faint);
  margin-top: 1.5rem;
  font-style: italic;
}

/* ---------- recall prompt (write-before-you-look) ---------- */

.recall {
  margin: 2rem 0;
  padding: 1.2rem 1.4rem;
  border: 1px dashed var(--ink-faint);
  border-radius: 6px;
  background: transparent;
}
.recall .label {
  display: block;
  font-size: 0.72rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--ink-faint);
  margin-bottom: 0.6rem;
}
.recall textarea {
  width: 100%;
  box-sizing: border-box;
  min-height: 4.5rem;
  font-family: inherit;
  font-size: 0.95rem;
  line-height: 1.5;
  padding: 0.6rem;
  border: 1px solid var(--rule);
  border-radius: 4px;
  background: var(--paper);
  color: var(--ink);
  resize: vertical;
}
.recall .reveal-btn {
  margin-top: 0.7rem;
  font-family: inherit;
  font-size: 0.85rem;
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--ink-faint);
  border-radius: 4px;
  background: transparent;
  color: var(--ink-soft);
  cursor: pointer;
}
.recall .reveal-btn:hover { background: #f6f1e8; }
.recall .answer { display: none; margin-top: 0.9rem; font-size: 0.94rem; color: var(--ink-soft); }
.recall .answer.shown { display: block; }

/* ---------- data table ---------- */

table { border-collapse: collapse; width: 100%; margin: 1.6rem 0; font-size: 0.94rem; }
th, td { text-align: left; padding: 0.55rem 0.8rem 0.55rem 0; border-bottom: 1px solid var(--rule); vertical-align: top; }
th { font-size: 0.74rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--ink-faint); font-weight: 700; }

/* ---------- footer / nav ---------- */

.lesson-footer {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 2px solid var(--ink);
  max-width: var(--measure);
  font-size: 0.92rem;
  color: var(--ink-soft);
}
.lesson-footer h3 { margin-top: 0; }

.nav-links { display: flex; flex-wrap: wrap; gap: 1.2rem; margin-top: 1.2rem; font-size: 0.88rem; }

.ask-teacher {
  margin-top: 2rem;
  padding: 1rem 1.2rem;
  background: var(--accent-bg);
  border-radius: 5px;
  font-size: 0.92rem;
}
.ask-teacher strong { color: var(--accent); }

.citation { font-size: 0.86rem; color: var(--ink-faint); }

/* ---------- index cards ---------- */

.card-list { display: flex; flex-direction: column; gap: 0.9rem; margin: 1.6rem 0; }

.card {
  display: block;
  padding: 1.1rem 1.3rem;
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: #fff;
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  color: var(--ink);
  transition: border-color 0.12s, box-shadow 0.12s, transform 0.12s;
}
a.card:hover {
  border-color: var(--accent);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.06);
  transform: translateY(-1px);
}

.card .card-num {
  font-size: 0.7rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--ink-faint);
}
.card h3 { margin: 0.25rem 0 0.3rem; font-size: 1.14rem; }
.card p { margin: 0; font-size: 0.93rem; color: var(--ink-soft); }
.card .card-tag {
  display: inline-block;
  margin-top: 0.6rem;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-weight: 700;
  padding: 0.18rem 0.5rem;
  border-radius: 3px;
  background: var(--accent-bg);
  color: var(--accent);
}
.card .card-tag.next { background: var(--gate-bg); color: var(--gate); }

/* ---------- markdown-rendered documents ---------- */

.md-body { max-width: var(--measure); }
.md-body h2:first-of-type { margin-top: 1.5rem; }
.md-body ul, .md-body ol { padding-left: 1.4rem; }
.md-body li { margin-bottom: 0.45rem; }
.md-body li > ul, .md-body li > ol { margin-top: 0.45rem; }
.md-body blockquote {
  margin: 1.5rem 0;
  padding: 0.2rem 0 0.2rem 1.1rem;
  border-left: 3px solid var(--rule);
  color: var(--ink-soft);
  font-style: italic;
}
.md-body table { font-size: 0.92rem; }
.md-body th, .md-body td { padding-right: 1rem; }
.md-body del { color: var(--ink-faint); }

/* ---------- measured numbers (baseline / progress readout) ---------- */

.stat-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin: 1.8rem 0;
  max-width: var(--measure);
}

.stat {
  flex: 1 1 8rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--rule);
  border-radius: 5px;
  background: #fff;
}

.stat .value {
  display: block;
  font-size: 1.55rem;
  font-weight: 650;
  line-height: 1.1;
  letter-spacing: -0.02em;
}
.stat .name {
  display: block;
  font-size: 0.7rem;
  letter-spacing: 0.11em;
  text-transform: uppercase;
  color: var(--ink-faint);
  font-weight: 700;
  margin-top: 0.35rem;
}
.stat .note { display: block; font-size: 0.8rem; color: var(--ink-soft); margin-top: 0.4rem; }

.stat.low   { border-left: 3px solid #b4483a; }
.stat.mid   { border-left: 3px solid var(--warn); }
.stat.good  { border-left: 3px solid var(--gate); }

/* ---------- two-track layout ---------- */

.track-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
  margin: 1.8rem 0;
  max-width: var(--measure);
}

.track {
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--rule);
  border-radius: 5px;
  background: #fff;
}
.track h4 {
  margin: 0 0 0.2rem;
  font-size: 1rem;
  font-weight: 650;
}
.track .track-label {
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--accent);
}
.track ul { margin: 0.7rem 0 0; padding-left: 1.1rem; font-size: 0.93rem; }
.track li { margin-bottom: 0.45rem; }

@media (max-width: 620px) {
  .track-grid { grid-template-columns: 1fr; }
}

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

@media (max-width: 1000px) {
  body { padding: 2.5rem 1.4rem 5rem; }
  .sidenote {
    float: none;
    width: auto;
    margin: 1.2rem 0;
    max-width: var(--measure);
    background: #faf6ef;
    padding: 0.8rem 0.9rem;
    border-radius: 0 4px 4px 0;
  }
}

/* ---------- print ---------- */

@media print {
  :root { --paper: #fff; }
  html { font-size: 11.5pt; }
  body { padding: 0; max-width: none; }
  a { color: var(--ink); border-bottom: none; }
  a[href^="http"]::after { content: " (" attr(href) ")"; font-size: 0.75em; color: #666; word-break: break-all; }
  .quiz, .recall, .ask-teacher { break-inside: avoid; }
  .quiz button.opt { border: 1px solid #999; }
  h2, h3 { break-after: avoid; }
  .ladder li, .callout { break-inside: avoid; }
  .no-print { display: none !important; }
}