/* 品牌色：青绿系，专业克制（非高饱和纯绿） */
:root,
:root > * {
  --md-primary-fg-color: #0d9488;
  --md-primary-fg-color--light: #2dd4bf;
  --md-primary-fg-color--dark: #0f766e;
  --md-accent-fg-color: #0d9488;

  --xhh-surface: #f8fafc;
  --xhh-surface-elevated: #ffffff;
  --xhh-border: #e2e8f0;
  --xhh-text: #0f172a;
  --xhh-muted: #64748b;
  --xhh-radius: 12px;
  --xhh-radius-lg: 16px;
  --xhh-shadow: 0 1px 2px rgba(15, 23, 42, 0.06), 0 8px 24px rgba(15, 23, 42, 0.06);
  --xhh-shadow-lg: 0 4px 6px rgba(15, 23, 42, 0.04), 0 20px 48px rgba(15, 23, 42, 0.1);
}

[data-md-color-scheme="slate"] {
  --md-hue: 170;
  --xhh-surface: #1e293b;
  --xhh-surface-elevated: #334155;
  --xhh-border: #475569;
  --xhh-text: #f1f5f9;
  --xhh-muted: #94a3b8;
  --xhh-shadow: 0 1px 2px rgba(0, 0, 0, 0.2), 0 8px 24px rgba(0, 0, 0, 0.25);
  --xhh-shadow-lg: 0 4px 6px rgba(0, 0, 0, 0.15), 0 20px 48px rgba(0, 0, 0, 0.35);
}

.video-embed {
  position: relative;
  width: 100%;
  max-width: 720px;
  margin: 1rem auto;
  aspect-ratio: 16 / 9;
  background: var(--xhh-surface-elevated);
  border-radius: var(--xhh-radius);
  overflow: hidden;
  box-shadow: var(--xhh-shadow);
  border: 1px solid var(--xhh-border);
}

.video-embed iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* 课程/教材页：封面居左显示 */
.md-typeset p:has(> img[src$="course1.jpg"]),
.md-typeset p:has(> img[src$="course2.jpg"]),
.md-typeset p:has(> img[src$="course3.jpg"]) {
  text-align: left;
}

.md-typeset img[src$="course1.jpg"],
.md-typeset img[src$="course2.jpg"],
.md-typeset img[src$="course3.jpg"] {
  display: block;
  margin-inline: 0;
}

/* 左侧导航：页面与分组标题图标对齐 */
nav.md-nav--primary .md-nav__link {
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

nav.md-nav--primary .md-nav__link > svg.lucide {
  flex-shrink: 0;
  width: 1.125rem;
  height: 1.125rem;
  stroke: var(--md-default-fg-color--light);
}

nav.md-nav--primary .md-nav__item--active > .md-nav__link > svg.lucide,
nav.md-nav--primary .md-nav__link--active > svg.lucide {
  stroke: var(--md-accent-fg-color);
}