/**
 * notes-mode.css
 * Chapter-notes reader layout — structurally matched to DiploMate's
 * study.css (chapter sidebar + progress bar + rich reader content:
 * formula cards, info boxes, key-points, PYQ callouts), reskinned to
 * RailStudy's light navy/amber theme.
 */

.study-page { min-height: 100vh; background: var(--rh-surface-1); display: flex; }

/* ── Chapter sidebar ──────────────────────────────────────── */
.study-sidebar {
  width: 272px; flex-shrink: 0; background: linear-gradient(180deg, var(--rh-navy-800) 0%, var(--rh-navy-950) 100%);
  position: fixed; top: 0; left: 0; bottom: 0; z-index: 100;
  display: flex; flex-direction: column; overflow: hidden; transition: transform 0.25s ease;
}
.study-sidebar-top { padding: 16px 16px 12px; border-bottom: 1px solid rgba(255,255,255,0.1); flex-shrink: 0; }
.study-back { display: flex; align-items: center; gap: 6px; font-size: var(--rh-fs-xs); color: var(--rh-navy-100); opacity: 0.75; text-decoration: none; margin-bottom: 10px; }
.study-back:hover { opacity: 1; color: #fff; text-decoration: none; }
.study-dept-label { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--rh-amber-500); margin-bottom: 4px; }
.study-dept-name { font-size: var(--rh-fs-base); font-weight: 700; color: #fff; }
.study-prog-bar { height: 3px; background: rgba(255,255,255,0.15); border-radius: 2px; margin-top: 10px; overflow: hidden; }
.study-prog-fill { height: 100%; background: var(--rh-amber-500); border-radius: 2px; transition: width 0.5s ease; }
.study-prog-label { font-size: 11px; color: var(--rh-navy-100); opacity: 0.7; margin-top: 4px; }

.study-chapter-nav { flex: 1; overflow-y: auto; padding: 8px; }
.study-sec-lbl { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--rh-navy-100); opacity: 0.55; padding: 10px 10px 4px; }
.ch-nav-item {
  display: flex; align-items: center; gap: 8px; padding: 7px 10px; border-radius: 8px;
  font-size: 13px; color: var(--rh-navy-100); cursor: pointer; text-decoration: none; margin-bottom: 1px;
}
.ch-nav-item:hover { background: rgba(255,255,255,0.08); color: #fff; }
.ch-nav-item.active { background: linear-gradient(90deg, rgba(239,159,39,0.2) 0%, rgba(239,159,39,0.08) 100%); color: var(--rh-amber-400); font-weight: 700; box-shadow: inset 2px 0 0 var(--rh-amber-500); }
.ch-nav-item.locked { opacity: 0.4; cursor: not-allowed; }
.ch-nav-num {
  width: 22px; height: 22px; border-radius: 6px; background: rgba(255,255,255,0.1);
  display: flex; align-items: center; justify-content: center; font-size: 11px; font-weight: 700; flex-shrink: 0; color: var(--rh-navy-100);
}
.ch-nav-item.active .ch-nav-num { background: var(--rh-amber-500); color: var(--rh-amber-text); }

.study-acc-hdr {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 10px; margin: 6px 0 2px; border-radius: 8px;
  background: rgba(255,255,255,0.04); border: 1px solid transparent;
  cursor: pointer; user-select: none; transition: border-color 0.15s ease, background 0.15s ease;
}
.study-acc-hdr:hover { background: rgba(255,255,255,0.08); }
.study-acc-hdr.open { border-color: rgba(239,159,39,0.35); background: rgba(239,159,39,0.06); }
.study-acc-hdr.has-active .study-acc-label { color: var(--rh-amber-400); }
.study-acc-label {
  font-size: 11px; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--rh-navy-100); flex: 1;
}
.study-acc-count {
  font-size: 10px; color: var(--rh-navy-100); opacity: 0.6;
  background: rgba(255,255,255,0.08); border-radius: 999px; padding: 1px 7px;
}
.study-acc-chevron { font-size: 9px; color: var(--rh-navy-100); opacity: 0.6; }
.study-acc-body { padding: 2px 0 6px; }
.study-acc-body .ch-nav-item { padding-left: 16px; }
.ch-nav-text { flex: 1; line-height: 1.3; }
.ch-nav-icon { font-size: 11px; flex-shrink: 0; }

.study-sidebar-overlay { display: none; position: fixed; inset: 0; background: rgba(4,44,83,0.5); z-index: 90; }
.study-sidebar-overlay.open { display: block; }

/* ── Main ─────────────────────────────────────────────────── */
.study-main { flex: 1; margin-left: 272px; min-height: 100vh; display: flex; flex-direction: column; }
.study-topbar {
  height: 54px; border-bottom: 1px solid var(--rh-border); display: flex; align-items: center; justify-content: space-between;
  padding: 0 var(--rh-space-5); background: rgba(255,255,255,0.92); backdrop-filter: blur(8px); position: sticky; top: 0; z-index: 50; flex-shrink: 0;
}
.study-topbar-left { display: flex; align-items: center; gap: 10px; }
.study-sidebar-toggle { background: none; border: none; color: var(--rh-text-primary); font-size: 1.2rem; cursor: pointer; padding: 4px; display: none; }
.study-chapter-badge { font-size: 11px; font-weight: 700; padding: 3px 10px; border-radius: 100px; background: rgba(12,68,124,0.08); color: var(--rh-navy-800); }
.study-topbar-title { font-size: 14px; font-weight: 600; color: var(--rh-text-primary); }
.study-action-btn {
  display: flex; align-items: center; gap: 6px; padding: 6px 12px; border-radius: 8px; font-size: 12px; font-weight: 600;
  border: 1px solid var(--rh-border-strong); background: var(--rh-surface-0); color: var(--rh-text-secondary); cursor: pointer; text-decoration: none;
}
.study-action-btn:hover { border-color: var(--rh-navy-700); color: var(--rh-navy-800); }
.study-action-btn.active { color: var(--rh-amber-600); border-color: var(--rh-amber-500); background: rgba(239,159,39,0.08); }

/* ── Notes reader body ────────────────────────────────────── */
.notes-body { flex: 1; max-width: 780px; margin: 0 auto; padding: 36px 32px 40px; width: 100%; }
.chapter-header { margin-bottom: var(--rh-space-6); padding-bottom: var(--rh-space-4); border-bottom: 1px solid var(--rh-border); }
.chapter-label { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--rh-amber-600); margin-bottom: 8px; }
.chapter-title { font-size: 1.7rem; font-weight: 800; line-height: 1.2; margin-bottom: 10px; color: var(--rh-text-primary); }
.chapter-meta { display: flex; gap: 14px; flex-wrap: wrap; }
.chapter-meta-item { display: flex; align-items: center; gap: 5px; font-size: 12px; color: var(--rh-text-muted); }

.notes-content h2 { font-size: 1.1rem; font-weight: 700; margin: 32px 0 12px; color: var(--rh-text-primary); display: flex; align-items: center; gap: 10px; }
.notes-content h2::after { content: ""; flex: 1; height: 1px; background: var(--rh-border); }
.notes-content h3 { font-size: 0.98rem; font-weight: 700; margin: 20px 0 8px; color: var(--rh-navy-800); }
.notes-content p { font-size: 14px; line-height: 1.8; color: var(--rh-text-secondary); margin-bottom: 12px; }
.notes-content ul, .notes-content ol { padding-left: 20px; margin-bottom: 14px; }
.notes-content li { font-size: 13px; line-height: 1.8; color: var(--rh-text-secondary); margin-bottom: 4px; }
.notes-content strong { color: var(--rh-text-primary); font-weight: 600; }

/* ── Formula card ─────────────────────────────────────────── */
.formula-card { background: var(--rh-surface-0); border: 1px solid rgba(239,159,39,0.3); border-left: 3px solid var(--rh-amber-500); border-radius: var(--rh-radius-md); padding: 16px 18px; margin: 18px 0; }
.formula-label { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--rh-amber-600); margin-bottom: 8px; }
.formula-eq { font-size: 1.2rem; font-weight: 700; color: var(--rh-text-primary); margin-bottom: 6px; }
.formula-desc { font-size: 13px; color: var(--rh-text-secondary); line-height: 1.6; }

/* ── Info boxes ───────────────────────────────────────────── */
.info-box { border-radius: var(--rh-radius-md); padding: 14px 16px; margin: 18px 0; display: flex; gap: 12px; }
.info-box.tip { background: rgba(31,138,85,0.06); border: 1px solid rgba(31,138,85,0.2); }
.info-box.warn { background: rgba(239,159,39,0.08); border: 1px solid rgba(239,159,39,0.25); }
.info-box.exam { background: rgba(34,112,173,0.08); border: 1px solid rgba(34,112,173,0.25); }
.info-box.info { background: var(--rh-surface-2); border: 1px solid var(--rh-border); }
.info-box-icon { font-size: 1rem; flex-shrink: 0; margin-top: 1px; }
.info-box-title { font-size: 12px; font-weight: 700; margin-bottom: 4px; color: var(--rh-text-primary); }
.info-box.tip .info-box-title { color: var(--rh-success); }
.info-box.warn .info-box-title { color: var(--rh-amber-600); }
.info-box.exam .info-box-title { color: var(--rh-navy-100); }
.info-box-text { font-size: 13px; color: var(--rh-text-secondary); line-height: 1.65; }

/* ── Key points ───────────────────────────────────────────── */
.key-points { background: var(--rh-surface-0); border: 1px solid var(--rh-border); border-radius: var(--rh-radius-lg); padding: 18px 22px; margin: 20px 0; }
.key-points-title { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--rh-amber-600); margin-bottom: 12px; }
.key-points ul { padding-left: 0; margin: 0; }
.key-points li { list-style: none; position: relative; padding: 6px 0 6px 22px; border-bottom: 1px solid var(--rh-border); font-size: 13px; color: var(--rh-text-secondary); }
.key-points li:last-child { border-bottom: none; }
.key-points li::before { content: "→"; color: var(--rh-amber-600); position: absolute; left: 0; top: 6px; }

/* ── PYQ callout inside notes ─────────────────────────────── */
.pyq-box { background: rgba(34,112,173,0.06); border: 1px solid rgba(34,112,173,0.2); border-radius: var(--rh-radius-lg); padding: 18px 22px; margin: 20px 0; }
.pyq-title { font-size: 11px; font-weight: 700; letter-spacing: 0.08em; text-transform: uppercase; color: var(--rh-navy-100); margin-bottom: 12px; }
.pyq-item { padding: 10px 0; border-bottom: 1px solid rgba(34,112,173,0.15); }
.pyq-item:last-child { border-bottom: none; }
.pyq-q { font-size: 13px; color: var(--rh-text-primary); margin-bottom: 4px; font-weight: 500; }
.pyq-meta { font-size: 11px; color: var(--rh-navy-100); opacity: 0.8; }

/* ── Content table (tap-changing charts, spec comparisons, etc.) ──── */
.content-table-wrap { overflow-x: auto; margin: 18px 0; border-radius: var(--rh-radius-md); border: 1px solid var(--rh-border); }
.content-table { width: 100%; border-collapse: collapse; font-size: 12.5px; }
.content-table th {
  background: var(--rh-surface-2); color: var(--rh-text-primary); font-weight: 700;
  text-align: left; padding: 8px 12px; white-space: nowrap; border-bottom: 1px solid var(--rh-border);
}
.content-table td { padding: 7px 12px; color: var(--rh-text-secondary); border-bottom: 1px solid var(--rh-border); }
.content-table tr:last-child td { border-bottom: none; }
.content-table tr:hover td { background: rgba(255,255,255,0.03); }

/* ── Prev/Next chapter nav ────────────────────────────────── */
.ch-nav-arrows { display: flex; align-items: center; justify-content: space-between; padding: var(--rh-space-5); border-top: 1px solid var(--rh-border); background: var(--rh-surface-0); flex-shrink: 0; }
.nav-arrow { display: flex; align-items: center; gap: 8px; padding: 10px 16px; border-radius: var(--rh-radius-md); border: 1px solid var(--rh-border-strong); background: var(--rh-surface-1); color: var(--rh-text-primary); text-decoration: none; font-size: 13px; font-weight: 600; }
.nav-arrow:hover { border-color: var(--rh-navy-700); color: var(--rh-navy-800); text-decoration: none; }
.nav-arrow.disabled { opacity: 0.3; pointer-events: none; }
.nav-arrow-sub { font-size: 11px; color: var(--rh-text-muted); font-weight: 400; display: block; }

@media (max-width: 900px) {
  .study-sidebar { transform: translateX(-100%); box-shadow: 4px 0 20px rgba(0,0,0,0.25); }
  .study-sidebar.open { transform: translateX(0); }
  .study-main { margin-left: 0; }
  .study-sidebar-toggle { display: inline-flex; align-items: center; justify-content: center; }
}
@media (max-width: 600px) {
  .notes-body { padding: 18px 16px 40px; }
  .chapter-title { font-size: 1.3rem; }
}

/* ── Syllabus-tree sidebar: chapter and topic headings above their notes ── */
.ch-nav-sub { padding: 8px 10px 3px 12px; font-size: 11px; font-weight: 700; letter-spacing: 0.04em; text-transform: uppercase; color: var(--rh-navy-100); opacity: 0.8; overflow-wrap: anywhere; }
.ch-nav-sub--topic { padding-left: 22px; font-size: 11px; text-transform: none; letter-spacing: 0; font-weight: 600; opacity: 0.7; }