:root {
  --topbar-gap: 42px;
  --topbar-gap-mobile: 28px;
}

.topbar,
.site-topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  width: 100%;
  border-bottom: 1px solid var(--line, var(--border));
  background: color-mix(in srgb, var(--surface, var(--bg)) 92%, transparent 8%);
  backdrop-filter: blur(8px);
}

.topbar-content,
.site-topbar-content {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  padding: 7px 18px;
}

.topbar-left,
.site-topbar-left {
  min-width: 0;
  display: flex;
  align-items: center;
  gap: 20px;
}

.brand-home,
.site-brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  color: var(--text, var(--fg));
  font-weight: 760;
  font-size: 14px;
  line-height: 1.1;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

.brand-home:visited,
.site-brand:visited {
  color: var(--text, var(--fg));
}

.brand-home img,
.site-brand-logo {
  width: 22px;
  height: 22px;
  border-radius: 7px;
  object-fit: cover;
  border: 0;
}

.main-nav,
.site-main-nav {
  min-width: 0;
  display: flex;
  align-items: center;
  gap: var(--topbar-gap);
}

.main-nav a,
.site-main-nav a {
  padding: 2px 0;
  border-bottom: 1px solid transparent;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  font-size: 13px;
  line-height: 1.2;
  font-weight: 650;
  letter-spacing: 0.005em;
  color: var(--muted, var(--fg));
  white-space: nowrap;
}

.main-nav a:hover,
.main-nav a[aria-current="page"],
.site-main-nav a:hover,
.site-main-nav a[aria-current="page"] {
  border-bottom-color: color-mix(in srgb, var(--accent-soft, var(--focus)) 55%, var(--line, var(--border)) 45%);
  color: var(--text, var(--fg));
}

.topbar-right,
.site-topbar-right {
  flex-shrink: 0;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.icon-btn,
.site-icon-btn {
  width: 32px;
  height: 32px;
  padding: 0;
  border-radius: 999px;
  border: 1px solid var(--line, var(--border));
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: var(--surface, var(--bg));
  color: var(--text, var(--fg));
  text-decoration: none;
  cursor: pointer;
}

.icon-btn:hover,
.site-icon-btn:hover {
  border-color: var(--line-strong, var(--grid-strong));
}

.icon-btn.active,
.site-icon-btn.active {
  border-color: color-mix(in srgb, var(--accent-soft, var(--focus)) 45%, var(--line-strong, var(--grid-strong)) 55%);
  background: color-mix(in srgb, var(--accent-soft, var(--focus)) 14%, var(--surface, var(--bg)) 86%);
}

.icon-btn svg,
.site-icon-btn svg {
  width: 15px;
  height: 15px;
  display: block;
}

.brand-home:focus-visible,
.site-brand:focus-visible,
.main-nav a:focus-visible,
.site-main-nav a:focus-visible,
.icon-btn:focus-visible,
.site-icon-btn:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

@media (max-width: 780px) {
  .topbar-content,
  .site-topbar-content {
    flex-wrap: wrap;
    row-gap: 8px;
    padding: 7px 10px;
  }

  .topbar-left,
  .site-topbar-left {
    width: 100%;
    display: block;
  }

  .brand-home,
  .site-brand {
    margin-bottom: 6px;
  }

  .main-nav,
  .site-main-nav {
    overflow-x: auto;
    padding-bottom: 2px;
    gap: var(--topbar-gap-mobile);
  }

  .main-nav a,
  .site-main-nav a {
    font-size: 12px;
  }

  .icon-btn,
  .site-icon-btn {
    width: 30px;
    height: 30px;
  }
}