/* ===== Root Catalog Page ===== */
header { background: var(--bg-header); border-bottom: 1px solid var(--border); padding: 48px 24px; text-align: center; }
header h1 { font-size: 2.4rem; font-weight: 700; margin-bottom: 8px; }
header p { color: var(--text-muted); font-size: 1.1rem; max-width: 560px; margin: 0 auto; }
main { max-width: 1100px; margin: 0 auto; padding: 48px 24px 80px; }
.section-label { font-size: 0.8rem; text-transform: uppercase; letter-spacing: 0.08em; color: var(--text-muted); margin-bottom: 20px; font-weight: 600; }
.courses { display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 24px; }
.course-card {
  background: var(--bg-surface);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 28px 24px;
  display: flex;
  flex-direction: column;
  transition: border-color 0.2s, transform 0.2s;
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
}
.course-card:hover { border-color: var(--accent-text); transform: translateY(-3px); text-decoration: none; }
.course-card, .course-card:hover, .course-card * { text-decoration: none !important; }
.course-card::before { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 4px; }
.course-card.llm::before { background: linear-gradient(90deg, #1f6feb, #8957e5); }
.course-card.hashcat::before { background: linear-gradient(90deg, #da3633, #f0883e); }
.course-card.helm::before { background: linear-gradient(90deg, #326ce5, #2ea043); }
.course-card.ctf-red::before { background: linear-gradient(90deg, #da3633, #8957e5); }
.course-card.ctf-blue::before { background: linear-gradient(90deg, #1f6feb, #2ea043); }
.course-card.ai-opsec::before { background: linear-gradient(90deg, #8957e5, #1f6feb); }
.course-card.ai-prompt::before { background: linear-gradient(90deg, #f0883e, #da3633); }
.course-card.ai-humor::before { background: linear-gradient(90deg, #f0883e, #d29922); }
.course-card.linux-net::before { background: linear-gradient(90deg, #f97316, #06b6d4); }
.course-card.mcp-servers::before { background: linear-gradient(90deg, #8b5cf6, #ec4899); }
.course-card.agents::before { background: linear-gradient(90deg, #10b981, #3b82f6); }
.course-card.it-landscape::before { background: linear-gradient(90deg, #f59e0b, #ef4444); }
.course-card.data-engineering::before { background: linear-gradient(90deg, #3b82f6, #8b5cf6); }
.course-card.cloud-devops::before { background: linear-gradient(90deg, #f59e0b, #14b8a6); }
.course-card.ai-for-dummies::before { background: linear-gradient(90deg, #fbbf24, #f97316); }
.course-card.exec-infosec::before { background: linear-gradient(90deg, #1e293b, #c9a227); }
.course-card.coming-soon::before { background: var(--border); }
.course-card.coming-soon { opacity: 0.55; pointer-events: none; }
.card-icon { font-size: 2rem; margin-bottom: 16px; }
.card-title { font-size: 1.2rem; font-weight: 600; margin-bottom: 8px; }
.card-desc { color: var(--text-muted); font-size: 0.88rem; flex: 1; margin-bottom: 20px; }
.card-meta { display: flex; gap: 8px; flex-wrap: wrap; }
.meta-tag { background: var(--bg-hover); border: 1px solid var(--border); border-radius: 20px; padding: 3px 12px; font-size: 0.72rem; color: var(--text-muted); }
.coming-badge {
  position: absolute; top: 16px; right: 16px;
  background: var(--bg-hover); border: 1px solid var(--border);
  border-radius: 20px; padding: 3px 12px;
  font-size: 0.7rem; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 0.05em; font-weight: 600;
}
/* Fixed theme picker — top right corner */
.theme-picker-fixed {
  position: fixed; top: 16px; right: 24px; z-index: 100;
  display: flex; align-items: center; gap: 6px;
  background: var(--bg-header); border: 1px solid var(--border);
  border-radius: 20px; padding: 6px 14px;
}
.theme-picker-fixed .theme-label { color: var(--text-muted); font-size: 0.72rem; margin-right: 4px; white-space: nowrap; }
.theme-picker-fixed button { width: 18px; height: 18px; border-radius: 50%; border: 2px solid var(--border); cursor: pointer; transition: all 0.15s; padding: 0; }
.theme-picker-fixed button:hover { transform: scale(1.2); }
.theme-picker-fixed button.active { border-color: var(--accent-text); box-shadow: 0 0 0 2px var(--accent-text); }
.theme-picker-fixed .t-dark { background: #0d1117; }
.theme-picker-fixed .t-light { background: #ffffff; }
.theme-picker-fixed .t-grey { background: #2b2b2b; }
.theme-picker-fixed .t-pink { background: #1a1020; }
.theme-picker-fixed .t-green { background: #0a0f0a; }
@media (max-width: 600px) { header h1 { font-size: 1.6rem; } .courses { grid-template-columns: 1fr; } .theme-picker-fixed { top: 8px; right: 12px; padding: 4px 10px; } }

/* ---- Course search & filter (catalog page only) ---- */
.catalog-filter { border: 1px solid var(--border); border-radius: 12px; background: var(--bg-hover); margin-bottom: 28px; overflow: hidden; }
.catalog-filter > summary { list-style: none; cursor: pointer; padding: 14px 18px; display: flex; align-items: center; justify-content: space-between; gap: 12px; font-weight: 600; user-select: none; }
.catalog-filter > summary::-webkit-details-marker { display: none; }
.catalog-filter > summary:hover { color: var(--accent-text); }
.cf-summary-hint { font-size: 0.72rem; font-weight: 400; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.06em; }
.catalog-filter[open] .cf-summary-hint::after { content: ''; }
.cf-body { padding: 4px 18px 18px; }
.cf-search { width: 100%; box-sizing: border-box; padding: 11px 14px; border: 1px solid var(--border); border-radius: 8px; background: var(--bg-body); color: var(--text-primary); font-size: 0.95rem; outline: none; transition: border-color 0.15s; }
.cf-search:focus { border-color: var(--accent-text); }
.cf-search::placeholder { color: var(--text-muted); }
.cf-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.cf-chip { background: none; border: 1px solid var(--border); border-radius: 20px; padding: 5px 14px; font-size: 0.78rem; color: var(--text-muted); cursor: pointer; transition: all 0.15s; }
.cf-chip:hover { border-color: var(--accent-text); color: var(--text-primary); }
.cf-chip.active { background: var(--accent-text); border-color: var(--accent-text); color: #fff; font-weight: 600; }
.cf-count { font-weight: 400; text-transform: none; letter-spacing: 0; color: var(--text-muted); margin-left: 6px; }
.cf-noresults { color: var(--text-muted); font-size: 0.9rem; margin: 0 0 20px; }
.cf-clear { background: none; border: 1px solid var(--border); border-radius: 6px; padding: 3px 10px; color: var(--accent-text); cursor: pointer; font-size: 0.82rem; }
.cf-clear:hover { border-color: var(--accent-text); }