/* Header & Nav */
header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
}

nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 88px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
}

.brand-mark {
  width: 36px;
  height: 36px;
  border: 1px solid var(--border-strong);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: 'Fraunces', serif;
  font-style: italic;
  font-weight: 500;
  font-size: 1.1rem;
  color: var(--text);
  position: relative;
}

.brand-mark::before {
  content: '';
  position: absolute;
  bottom: -3px;
  right: -3px;
  width: 6px;
  height: 6px;
  background: var(--accent);
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-name {
  font-family: 'Fraunces', serif;
  font-weight: 500;
  font-size: 0.98rem;
  color: var(--text);
  letter-spacing: -0.01em;
}

.brand-role {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.66rem;
  color: var(--text-muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-top: 2px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-menu a {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
  transition: color var(--t-fast);
  position: relative;
  padding: 4px 0;
}

.nav-menu a::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--accent);
  transition: width var(--t-base);
}

.nav-menu a:hover { color: var(--text); }
.nav-menu a:hover::after { width: 100%; }

.theme-toggle {
  width: 36px;
  height: 36px;
  border: 1px solid var(--border-strong);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: color var(--t-fast), border-color var(--t-fast);
}

.theme-toggle:hover {
  color: var(--accent);
  border-color: var(--accent-border);
}

.theme-toggle svg { width: 14px; height: 14px; }
[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }
[data-theme="light"] .icon-moon { display: block; }

@media (max-width: 960px) {
  .nav-menu { display: none; }
  nav { height: 72px; }
}