/* lesson-sidebar.css — MedStudy-style sticky unit sidebar for chemistry
 * lesson pages, themed via the site's existing --bg/--card/--ink/--accent
 * custom properties (dark/light/sepia all supported automatically). */

.gt-lesson-layout {
  display: flex;
  max-width: 1320px;
  margin: 0 auto;
  gap: 26px;
  align-items: flex-start;
  padding: 0 16px;
}
.gt-lesson-main { flex: 1; min-width: 0; }
.gt-lesson-main .lesson-wrap { max-width: none; margin: 0; padding-left: 0; padding-right: 0; }

.gt-sidebar {
  width: 232px;
  flex-shrink: 0;
  position: sticky;
  top: 84px;
  max-height: calc(100vh - 100px);
  overflow-y: auto;
}
.gt-sidebar-box {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius, 12px);
  box-shadow: var(--shadow);
  overflow: hidden;
}
.gt-sidebar-header {
  background: var(--accent);
  color: #0b1020;
  padding: 11px 16px;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: .4px;
  line-height: 1.4;
}
.gt-sidebar-box nav { display: flex; flex-direction: column; }
.gt-sidebar-box nav a {
  display: block;
  padding: 9px 16px;
  font-size: 13px;
  color: var(--ink-dim);
  text-decoration: none;
  border-left: 3px solid transparent;
  border-bottom: 1px solid var(--line);
  transition: all .15s;
}
.gt-sidebar-box nav a:last-child { border-bottom: none; }
.gt-sidebar-box nav a:hover {
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  color: var(--ink);
}
.gt-sidebar-box nav a.active {
  background: color-mix(in srgb, var(--accent) 18%, transparent);
  border-left-color: var(--accent);
  color: var(--ink);
  font-weight: 700;
}
.gt-sidebar-home {
  display: block;
  margin-top: 12px;
  text-align: center;
  padding: 8px 12px;
  border: 1.5px dashed var(--line);
  border-radius: 8px;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--ink-dim);
  text-decoration: none;
  transition: all .15s;
}
.gt-sidebar-home:hover { border-color: var(--accent); color: var(--ink); }

@media (max-width: 900px) {
  .gt-sidebar { display: none; }
  .gt-lesson-layout { padding: 0; }
}