.site-header {
  position: sticky;
  top: 20px;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 32px;
  width: calc(100% - 64px);
  max-width: 1320px;
  height: 68px;
  margin: 20px auto 0;
  padding: 0 22px;
  border: 1px solid rgba(255, 255, 255, .09);
  border-radius: 1.25rem;
  background: rgba(18, 18, 20, .62);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .035), 0 8px 28px rgba(0, 0, 0, .12);
  backdrop-filter: blur(22px) saturate(140%);
  -webkit-backdrop-filter: blur(22px) saturate(140%);
}

:root[data-theme="light"] .site-header {
  background: rgba(255, 255, 255, .82);
  border-color: rgba(222, 222, 226, .72);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, .7), 0 4px 18px rgba(21, 21, 23, .025);
  backdrop-filter: blur(18px) saturate(140%);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
}

.site-header .brand {
  display: flex;
  align-items: center;
  flex: 0 1 auto;
  gap: 12px;
  min-height: 44px;
  margin: 0;
  font-size: 15px;
  font-weight: 650;
  letter-spacing: 0;
  white-space: nowrap;
}

.site-header .brand img { width: 36px; height: 36px; object-fit: contain; }

.site-header nav {
  display: flex;
  align-items: center;
  gap: 28px;
  width: auto;
  margin: 0 0 0 auto;
  padding: 0;
  border: 0;
  font-size: 14px;
  font-weight: 400;
  line-height: 1.5;
  text-transform: none;
}

.site-header nav a,
.site-header nav a[aria-current] {
  display: flex;
  align-items: center;
  min-height: 44px;
  padding: 12px 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  box-shadow: none;
  color: var(--muted);
  font: inherit;
  text-transform: none;
}

.site-header nav a:hover,
.site-header nav a[aria-current],
.site-header nav a[aria-current]:hover { color: var(--ink); background: transparent; }

.site-header .header-actions {
  display: flex;
  align-items: center;
  flex: 0 0 auto;
  gap: 4px;
  padding-left: 16px;
  border-left: 1px solid var(--line);
}

.site-header .icon-button {
  display: grid;
  place-items: center;
  width: 36px;
  height: 36px;
  padding: 0;
  border: 0;
  border-radius: 4px;
  background: transparent;
  color: var(--ink);
  cursor: pointer;
}

.site-header .icon-button:hover { background: var(--line); }
.site-header .icon-button svg { width: 20px; height: 20px; }
.site-header .theme-toggle { border-radius: 50%; }
.site-header .menu-toggle { display: none; }

@media (min-width: 641px) {
  .site-header .header-actions { display: none; }
}

@media (max-width: 640px) {
  .site-header {
    top: 12px;
    width: calc(100% - 24px);
    height: 60px;
    margin-top: 12px;
    padding: 0 14px;
    gap: 12px;
  }

  .site-header .brand { min-width: 0; font-size: 14px; }
  .site-header .header-actions { margin-left: auto; padding: 0; border: 0; }
  .site-header .menu-toggle { display: grid; }
  .site-header nav {
    display: flex;
    justify-content: space-between;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    width: auto;
    margin: 0;
    padding: 12px 20px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--stage, var(--panel));
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transform: translateY(-10px);
    transition: opacity 220ms ease, transform 220ms ease, visibility 0s linear 220ms;
  }

  .site-header.menu-open nav {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateY(0);
    transition-delay: 0s;
  }
}

@media (prefers-reduced-motion: reduce) {
  .site-header nav { transition: none; }
}