/* teach-kite shared stylesheet — Tufte-inspired, prints well */
:root {
  --serif: "Iowan Old Style", "Palatino Linotype", "Book Antiqua", Palatino, Georgia, serif;
  --sans: -apple-system, "Segoe UI", Roboto, "Helvetica Neue", sans-serif;
  --mono: "JetBrains Mono", "SF Mono", Menlo, Consolas, monospace;
  --ink: #1a1a1a;
  --muted: #6b6b6b;
  --rule: #d0d0d0;
  --accent: #8b0000;
  --bg-soft: #faf8f5;
  --warn-bg: #fff7e6;
  --warn-border: #e0a800;
}

* { box-sizing: border-box; }

html { font-size: 16px; }

body {
  font-family: var(--serif);
  color: var(--ink);
  line-height: 1.6;
  max-width: 760px;
  margin: 0 auto;
  padding: 2rem 1.5rem 4rem;
  background: #fff;
}

header.lesson-head {
  border-bottom: 2px solid var(--ink);
  padding-bottom: 0.8rem;
  margin-bottom: 2rem;
}
header.lesson-head .num {
  font-family: var(--sans);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--muted);
}
header.lesson-head h1 {
  font-size: 1.7rem;
  line-height: 1.25;
  margin: 0.3rem 0 0;
  font-weight: 600;
}
header.lesson-head .mission-tag {
  font-family: var(--sans);
  font-size: 0.82rem;
  color: var(--muted);
  margin-top: 0.4rem;
}

h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2rem 0 0.6rem;
  border-bottom: 1px solid var(--rule);
  padding-bottom: 0.2rem;
}
h3 { font-size: 1.05rem; font-weight: 600; margin: 1.4rem 0 0.4rem; }

p { margin: 0.5rem 0; }

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

code, .mono { font-family: var(--mono); font-size: 0.88em; }
code { background: var(--bg-soft); padding: 0.1em 0.3em; border-radius: 3px; }

.math, mjx-container { font-size: 1.02em; }

blockquote {
  border-left: 3px solid var(--rule);
  margin: 0.8rem 0;
  padding: 0.2rem 0 0.2rem 1rem;
  color: #444;
  font-style: italic;
}

.warning {
  background: var(--warn-bg);
  border: 1px solid var(--warn-border);
  border-left: 4px solid var(--warn-border);
  padding: 0.6rem 0.9rem;
  margin: 1rem 0;
  border-radius: 3px;
  font-size: 0.94rem;
}

.note {
  background: var(--bg-soft);
  border-left: 3px solid var(--accent);
  padding: 0.5rem 0.9rem;
  margin: 1rem 0;
  border-radius: 0 3px 3px 0;
  font-size: 0.94rem;
}

ul, ol { padding-left: 1.3rem; }
li { margin: 0.25rem 0; }

.meta-list { font-family: var(--sans); font-size: 0.9rem; }
.meta-list dt { font-weight: 600; color: var(--muted); }
.meta-list dd { margin: 0 0 0.4rem; }

/* data-flow diagram */
.flow-diagram {
  background: var(--bg-soft);
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 1rem;
  margin: 1rem 0;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 0.82rem;
  line-height: 1.5;
  white-space: pre;
}

/* quiz */
.quiz {
  border: 1px solid var(--rule);
  border-radius: 4px;
  padding: 1rem 1.2rem;
  margin: 1.4rem 0;
  background: #fdfdfb;
}
.quiz .q-label {
  font-family: var(--sans); font-size: 0.75rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--accent); font-weight: 600;
}
.quiz .question { font-weight: 600; margin: 0.3rem 0 0.8rem; }
.quiz .answers { display: flex; flex-direction: column; gap: 0.5rem; }
.quiz button {
  font-family: var(--serif); font-size: 0.95rem; text-align: left;
  background: #fff; border: 1px solid var(--rule); border-radius: 3px;
  padding: 0.45rem 0.8rem; cursor: pointer; transition: all 0.15s;
}
.quiz button:hover { border-color: var(--accent); }
.quiz button.correct { background: #e6f4e6; border-color: #3a8a3a; }
.quiz button.wrong { background: #fbe8e8; border-color: #b33; }
.quiz .feedback { margin-top: 0.6rem; font-size: 0.9rem; display: none; }
.quiz .feedback.show { display: block; }

footer.lesson-foot {
  margin-top: 2.5rem; padding-top: 1rem; border-top: 1px solid var(--rule);
  font-family: var(--sans); font-size: 0.85rem; color: var(--muted);
}
footer.lesson-foot a { color: var(--accent); }
.speak-cue {
  font-family: var(--sans); font-size: 0.8rem; color: var(--muted);
  border-top: 1px dashed var(--rule); margin-top: 1.5rem; padding-top: 0.6rem;
}
.speak-cue::before { content: "🗣 口述线索："; font-weight: 600; }

@media print {
  body { max-width: none; padding: 1.5rem; }
  .quiz button { color: #333; }
  a { color: #333; }
}