/* CSS dùng chung cho các bài học 4 kỹ năng. Không CDN, không build, không JS. */
:root {
  --bg: #f7f6f3;
  --card: #ffffff;
  --ink: #23201d;
  --muted: #6b6560;
  --line: #e3ded8;
  --accent: #8c5a3c;
  --accent-soft: #fdf4ec;
  --en: #1f4d3d;
  --info-soft: #f2f6f3;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  padding: 0 0 60px;
}
.wrap { max-width: 820px; margin: 0 auto; padding: 0 18px; }
header {
  background: var(--card);
  border-bottom: 1px solid var(--line);
  padding: 24px 0 20px;
  margin-bottom: 24px;
}
header .wrap { padding-bottom: 0; }
h1 { font-size: 1.45rem; line-height: 1.35; margin: 0 0 6px; }
.meta { color: var(--muted); font-size: .9rem; margin: 0; }
h2 { font-size: 1.08rem; margin: 30px 0 10px; padding-bottom: 7px; border-bottom: 2px solid var(--accent-soft); }
h3 { font-size: 1rem; margin: 20px 0 8px; color: var(--accent); }
p { margin: 0 0 12px; }
ul, ol { margin: 0 0 12px; padding-left: 22px; }
li { margin-bottom: 5px; }
.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 16px 18px;
  margin-bottom: 16px;
}
.en { color: var(--en); }
.badge {
  display: inline-block;
  background: var(--accent-soft);
  color: var(--accent);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 2px 11px;
  font-size: .78rem;
  font-weight: 600;
  margin-right: 6px;
}
.stop {
  background: var(--info-soft);
  border-left: 4px solid var(--en);
  border-radius: 0 8px 8px 0;
  padding: 10px 14px;
  font-size: .92rem;
  margin: 14px 0;
}
table { width: 100%; border-collapse: collapse; margin: 0 0 16px; font-size: .95rem; }
th, td { text-align: left; padding: 8px 10px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { color: var(--muted); font-weight: 600; font-size: .84rem; text-transform: uppercase; letter-spacing: .03em; }
details {
  background: var(--accent-soft);
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 10px 14px;
  margin: 0 0 14px;
}
details > summary { cursor: pointer; font-weight: 600; color: var(--accent); font-size: .95rem; }
details[open] > summary { margin-bottom: 10px; }
figure { margin: 0 0 14px; }
img {
  display: block;
  width: 100%;
  max-width: 100%;
  height: auto;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: #eee;
}
audio { width: 100%; margin: 4px 0 10px; }
.credit { font-size: .82rem; color: var(--muted); margin: 0 0 12px; }
.credit a { color: var(--accent); }
.dialogue { margin: 0; padding: 0; list-style: none; }
.dialogue li { margin-bottom: 8px; }
.dialogue b { color: var(--accent); }
.passage {
  background: var(--card);
  border: 1px solid var(--line);
  border-left: 4px solid var(--en);
  border-radius: 0 10px 10px 0;
  padding: 14px 16px;
  margin-bottom: 14px;
}
.passage p { margin-bottom: 10px; }
.q { margin-bottom: 10px; }
.checklist { list-style: none; padding-left: 0; }
.checklist li { padding-left: 26px; position: relative; margin-bottom: 6px; }
.checklist li::before {
  content: "";
  position: absolute; left: 0; top: 7px;
  width: 15px; height: 15px;
  border: 1.5px solid var(--accent);
  border-radius: 4px;
}
.prompt {
  background: var(--info-soft);
  border-left: 4px solid var(--en);
  border-radius: 0 8px 8px 0;
  padding: 13px 15px;
  white-space: pre-wrap;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .86rem;
  line-height: 1.55;
}
.answer {
  background: var(--info-soft);
  border-left: 4px solid var(--en);
  border-radius: 0 8px 8px 0;
  padding: 13px 15px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: .86rem;
  line-height: 1.7;
  white-space: pre-wrap;
}
.fill { border-bottom: 1px dotted var(--muted); display: inline-block; min-width: 150px; }
footer { color: var(--muted); font-size: .8rem; margin-top: 32px; border-top: 1px solid var(--line); padding-top: 12px; }
@media (max-width: 600px) {
  body { font-size: 16px; }
  .card { padding: 14px 15px; }
  h1 { font-size: 1.24rem; }
  .passage { padding: 12px 13px; }
}