:root {
  --bg: #0b1020;
  --panel: #121a33;
  --text: #e9ecf6;
  --muted: #a9b1d6;
  --link: #7aa2f7;
  --border: rgba(255, 255, 255, 0.12);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.container {
  max-width: 980px;
  margin: 0 auto;
  padding: 24px;
}

.site-header, .site-footer {
  border-bottom: 1px solid var(--border);
  background: rgba(18, 26, 51, 0.6);
  backdrop-filter: blur(8px);
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
}

.site-footer {
  border-bottom: none;
  border-top: 1px solid var(--border);
  padding: 14px 24px;
  color: var(--muted);
  font-size: 12px;
}

.brand {
  color: var(--text);
  text-decoration: none;
  font-weight: 700;
}

.nav a {
  color: var(--muted);
  text-decoration: none;
  margin-left: 12px;
}

.nav a:hover { color: var(--text); }

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 18px;
}

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 16px;
}

a.link {
  color: var(--link);
  text-decoration: none;
  font-weight: 600;
}

a.link:hover { text-decoration: underline; }

.h1 {
  margin: 0 0 12px 0;
  font-size: 28px;
}

.p {
  margin: 0 0 12px 0;
  color: var(--muted);
  line-height: 1.5;
}

.breadcrumbs {
  margin-bottom: 14px;
  font-size: 13px;
  color: var(--muted);
}
.details {
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 22px 26px;
  background: rgba(255, 255, 255, 0.035);
  font-size: 18px;
}
.details + .details {
  margin-top: 18px;
}

.summary {
  cursor: pointer;
  font-weight: 800;
  font-size: 26px;
  list-style: none;
}

.summary::-webkit-details-marker {
  display: none;
}

.summary::after {
  content: "▸";
  float: right;
  opacity: 0.85;
}

details[open] .summary::after {
  content: "▾";
}

.file-list {
  margin: 10px 0 0 0;
  padding: 0 0 0 18px;
}

.file-list li {
  margin: 10px 0;
  font-size: 16px;
}
.course-title-link {
  display: block;
  width: 100%;
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  line-height: 1.3;
}

.course-title-link:hover {
  text-decoration: underline;
}

.course-card {
  min-height: 96px;
  display: flex;
  align-items: center;
}