:root {
  --bg: #0d1117;
  --surface: #161b22;
  --border: #30363d;
  --text: #e6edf3;
  --muted: #8b949e;
  --accent: #58a6ff;
}
* { box-sizing: border-box; }
body {
  margin: 0; background: var(--bg); color: var(--text);
  font-family: -apple-system, "Segoe UI", "PingFang TC", "Microsoft JhengHei", sans-serif;
  line-height: 1.6;
}
.hero { padding: 3rem 1rem 2rem; text-align: center; border-bottom: 1px solid var(--border); }
.hero h1 { margin: 0; font-size: 2rem; }
.hero p { color: var(--muted); margin: .5rem 0 0; }
main { max-width: 900px; margin: 0 auto; padding: 2rem 1rem; }
.persona-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(260px, 1fr)); gap: 1rem; }
.persona-card {
  display: block; background: var(--surface); border: 1px solid var(--border);
  border-radius: 10px; padding: 1.25rem; color: var(--text); text-decoration: none;
  transition: border-color .2s;
}
.persona-card:hover { border-color: var(--accent); }
.persona-icon { font-size: 2rem; }
.persona-title { margin: .5rem 0; font-size: 1.15rem; }
.persona-work, .persona-goal { color: var(--muted); font-size: .9rem; margin: .25rem 0; }
.explore-card {
  background: linear-gradient(160deg, #10243c 0%, var(--surface) 70%);
  border: 2px solid var(--accent);
}
.explore-card:hover { border-color: #79c0ff; }
.explore-card .persona-title { color: var(--accent); }
.course-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  width: 90vw;
  margin: 0 auto;
}
.course-card {
  display: block; background: var(--surface); border: 1px solid var(--border);
  border-radius: 10px; padding: 1.25rem; color: var(--text); text-decoration: none;
  transition: border-color .2s;
}
.course-card:hover { border-color: var(--accent); }
.course-title { margin: 0 0 .5rem; font-size: 1.1rem; color: var(--accent); }
.course-desc { color: var(--muted); font-size: .9rem; margin: 0 0 .75rem; }
.course-topics { display: flex; flex-wrap: wrap; gap: .35rem; }
.course-topic {
  background: #1f2937; border: 1px solid var(--border); border-radius: 999px;
  padding: .15rem .6rem; color: var(--muted); font-size: .75rem;
}
.timeline { display: flex; flex-direction: column; gap: 1.5rem; }
.stage { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 1.25rem; }
.stage-head { display: flex; align-items: baseline; gap: .75rem; flex-wrap: wrap; }
.stage-num { color: var(--accent); font-weight: 700; }
.stage-title { margin: 0; font-size: 1.15rem; }
.stage-weeks { color: var(--muted); font-size: .85rem; }
.stage-objective { color: var(--muted); }
.site-list { list-style: none; padding: 0; margin: 1rem 0 0; }
.site-item { border-top: 1px solid var(--border); padding: .75rem 0; }
.site-link { color: var(--accent); text-decoration: none; font-weight: 600; }
.site-link:hover { text-decoration: underline; }
.site-reason, .site-start { color: var(--muted); font-size: .88rem; margin: .2rem 0 0; }
.error-box { background: #3d1d1d; border: 1px solid #da3633; color: #f0b2b2; padding: 1rem; border-radius: 8px; }
.hidden { display: none; }
.other-personas { display: flex; flex-wrap: wrap; gap: .5rem; justify-content: center; padding: 1rem; }
.persona-chip {
  background: var(--surface); border: 1px solid var(--border); border-radius: 999px;
  padding: .35rem .9rem; color: var(--text); text-decoration: none; font-size: .85rem;
}
.persona-chip:hover { border-color: var(--accent); }
footer { color: var(--muted); text-align: center; padding: 2rem 1rem; font-size: .85rem; }
@media (max-width: 600px) { .hero h1 { font-size: 1.5rem; } }
@media (max-width: 1100px) { .course-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .course-grid { grid-template-columns: 1fr; width: 100%; } }