/* Course pages */
.back-link { display: inline-block; margin-bottom: 1.5rem; font-size: 0.9rem; font-weight: 500; }

.course-intro { color: var(--text-muted); margin-bottom: 2rem; max-width: 640px; }

.weeks { display: flex; flex-direction: column; gap: 1rem; }

.week {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 1.2rem 1.4rem;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.week:hover { border-color: var(--accent); box-shadow: 0 2px 10px rgba(0,0,0,0.05); }

.week-head { display: flex; align-items: baseline; gap: 0.8rem; flex-wrap: wrap; margin-bottom: 0.8rem; }
.week-num {
  font-size: 0.85rem; font-weight: 700; color: var(--accent);
  background: var(--bg-alt); border: 1px solid var(--border);
  border-radius: 999px; padding: 0.2rem 0.9rem; white-space: nowrap;
}

/* Two sessions per week */
.sessions { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.session {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.9rem 1rem;
}
.session-num {
  display: inline-block;
  font-size: 0.72rem; font-weight: 600; letter-spacing: 0.02em;
  text-transform: uppercase; color: var(--text-muted);
  margin-bottom: 0.35rem;
}
.session-title { font-size: 1rem; font-weight: 600; margin: 0 0 0.4rem; }

.week-keywords { font-size: 0.88rem; color: var(--text-muted); margin-bottom: 0.4rem; }
.week-keywords strong { color: var(--text); font-weight: 600; }

.week-notes { margin: 0; }
.week-notes a { font-size: 0.88rem; font-weight: 500; }

/* Sessions without a topic yet */
.session-tbd { opacity: 0.55; }
.session-tbd .session-title { font-weight: 500; color: var(--text-muted); font-style: italic; }

@media (max-width: 600px) {
  .sessions { grid-template-columns: 1fr; }
}

/* Individual note page */
.note-body { max-width: 720px; }
.note-body h2 { font-size: 1.15rem; font-weight: 600; margin-top: 1.6rem; margin-bottom: 0.5rem; }
.note-body p { margin-bottom: 0.8rem; }
.note-body ul { list-style: disc; padding-left: 1.3rem; margin-bottom: 0.8rem; }
.note-body li { padding: 0.15rem 0; }
.note-meta { color: var(--text-muted); font-size: 0.9rem; margin-bottom: 1.5rem; }
.keyword-chips { display: flex; flex-wrap: wrap; gap: 0.5rem; margin: 1rem 0 2rem; }
.keyword-chips span {
  font-size: 0.82rem; color: var(--text-muted);
  background: var(--bg-alt); border: 1px solid var(--border);
  border-radius: 999px; padding: 0.2rem 0.7rem;
}

/* Exam topics widget */
.exam-topics {
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}
.exam-title { font-size: 1.3rem; font-weight: 700; margin-bottom: 0.3rem; }
.exam-intro { margin-bottom: 1.2rem; }

.topic-list { list-style: none; padding: 0; margin: 0; counter-reset: topic; display: flex; flex-direction: column; gap: 0.6rem; }
.topic-list li { margin: 0; }

.topic {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  overflow: hidden;
}
.topic summary {
  cursor: pointer;
  padding: 0.85rem 1.1rem;
  font-weight: 600;
  font-size: 0.95rem;
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.6rem;
  transition: background 0.15s;
}
.topic summary::-webkit-details-marker { display: none; }
.topic summary::before {
  content: "+";
  color: var(--accent);
  font-weight: 700;
  font-size: 1.1rem;
  width: 1rem;
  text-align: center;
  flex-shrink: 0;
}
.topic[open] summary::before { content: "\2212"; } /* minus */
.topic summary:hover { background: var(--bg-alt); }
.topic[open] summary { border-bottom: 1px solid var(--border); }

.topic-body { padding: 0.9rem 1.1rem; }
.topic-body p { margin: 0; font-size: 0.9rem; color: var(--text-muted); }

/* References widget */
.references {
  margin-top: 2.5rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
}
.ref-downloads { display: flex; flex-wrap: wrap; gap: 1rem; }
.ref-btn {
  display: flex;
  align-items: center;
  gap: 0.8rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.9rem 1.1rem;
  background: var(--bg);
  min-width: 240px;
  transition: border-color 0.15s, box-shadow 0.15s;
}
.ref-btn:hover { border-color: var(--accent); box-shadow: 0 2px 10px rgba(0,0,0,0.05); text-decoration: none; }
.ref-btn-icon { font-size: 1.6rem; line-height: 1; }
.ref-btn-text { display: flex; flex-direction: column; }
.ref-btn-text strong { color: var(--text); font-size: 0.95rem; }
.ref-btn-text .muted { font-size: 0.82rem; }