.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 0 16px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-primary);
  z-index: 20;
}

.site-header .brand {
  font-weight: 600;
  text-decoration: none;
  color: var(--text-primary);
  padding: 4px 8px;
  border-radius: 4px;
  position: relative;
  z-index: 2; /* Above glass indicator */
}

.site-header .brand:hover,
.site-header .brand:focus-visible {
  text-decoration: underline;
  background: var(--hover-overlay);
}

.site-header .nav {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  align-items: center;
  position: relative;
  z-index: 2; /* Above glass indicator */
}

.site-header .nav a {
  text-decoration: none;
  color: var(--text-primary);
  padding: 4px 8px;
  border-radius: 4px;
  position: relative;
  z-index: 2; /* Above glass indicator (z-index: 1) */
}

.site-header .nav a:hover,
.site-header .nav a:focus-visible {
  background: var(--hover-overlay);
}

/* ===== Glass Indicator for Active Section ===== */
/* Positioned absolute inside header */
.nav-glass-indicator {
  position: absolute;
  top: 50%;
  left: 0;
  height: 32px;
  transform: translateY(-50%) translateX(0);
  border-radius: 6px;
  pointer-events: none;
  z-index: 1; /* Below nav links which have z-index: 2 */
  will-change: transform, width;
  
  /* Glass effect */
  background: rgba(255, 255, 255, 0.08);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border: 1px solid rgba(255, 255, 255, 0.15);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.1);
  
  opacity: 0;
  width: 60px;
}

/* After initial position, enable sliding animation */
.nav-glass-indicator.is-ready {
  transition: transform 0.4s cubic-bezier(0.25, 0.1, 0.25, 1), width 0.4s cubic-bezier(0.25, 0.1, 0.25, 1), opacity 0.2s ease;
}

.nav-glass-indicator.is-visible {
  opacity: 1;
}

/* Light mode glass effect - subtle tint */
:root[data-theme="light"] .nav-glass-indicator {
  background: rgba(0, 0, 0, 0.04);
  border: 1px solid rgba(0, 0, 0, 0.08);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.05);
}

/* Dark mode glass effect - subtle tint */
:root[data-theme="dark"] .nav-glass-indicator {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.2);
}

/* Subtle red accent on bottom edge */
.nav-glass-indicator::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 10%;
  right: 10%;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
  opacity: 0.6;
}

/* === GitHub icon === */
.site-header .nav .nav-github {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  padding: 0;
  border-radius: 4px;
  line-height: 0;
}

.nav-github .gh{
  width: 30px;
  height: 30px;
  display: block;
}

:root[data-theme="light"] .nav-github .gh { filter: none; }
:root[data-theme="dark"] .nav-github .gh { filter: brightness(0) invert(1); }

.nav-github:hover {
  background: var(--hover-overlay);
}

.nav-github:hover .gh{
  transform: translateY(-1px);
  transition: transform .18s ease;
}

/* === Theme toggle === */
.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  padding: 0;
  border: 0;
  border-radius: 4px;
  background: transparent;
  cursor: pointer;
  line-height: 0;
}

.theme-toggle:hover {
  background: var(--hover-overlay);
  transform: translateY(-1px);
  transition: transform .18s ease;
}

.theme-toggle:focus-visible {
  outline: 2px solid currentColor;
  outline-offset: 2px;
}

.theme-toggle .icon {
  display: none;
  width: 30px;
  height: 30px;
}

:root[data-theme="light"] .theme-toggle .icon-moon {
  display: block;
  filter: none;
}

:root[data-theme="dark"] .theme-toggle .icon-sun {
  display: block;
  filter: brightness(0) invert(1);
}