html { overflow-y: scroll; }

/* 顶栏 */
.topbar {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  display: flex;
  align-items: center;
  gap: var(--space-6);
  height: 64px;
  padding: 0 var(--space-6);
  background: rgba(13, 17, 18, .72);
  backdrop-filter: blur(18px) saturate(140%);
  -webkit-backdrop-filter: blur(18px) saturate(140%);
  border-bottom: 1px solid var(--border-subtle);
  transition:
    background var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-out),
    box-shadow var(--dur-base) var(--ease-out);
}
body.auth-active > [data-topbar] {
  display: none !important;
}
.topbar.is-scrolled {
  background: rgba(13, 17, 18, .94);
  border-bottom-color: var(--border-emphasis);
  box-shadow: 0 16px 38px rgba(0, 0, 0, .30);
}

.topbar-brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  color: var(--text-primary);
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 17px;
  letter-spacing: .04em;
  line-height: 1;
  text-decoration: none;
  text-transform: uppercase;
  transition: color var(--dur-base) var(--ease-out), transform var(--dur-base) var(--ease-out);
}
.topbar-brand:hover { color: var(--accent-primary-2); transform: translateY(-1px); }
.topbar-brand img {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  filter: drop-shadow(0 0 10px rgba(72, 230, 199, .34));
}

.topbar-nav {
  display: flex;
  align-items: center;
  gap: 4px;
  flex: 1;
}
.topbar-nav a {
  position: relative;
  padding: 8px 14px;
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 14px;
  border-radius: var(--radius-sm);
  transition: color var(--dur-base) var(--ease-out), background var(--dur-base) var(--ease-out);
}
.topbar-nav a:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, .04);
}
.topbar-nav a.is-active { color: var(--text-primary); }
.topbar-nav a.is-active::after {
  content: '';
  position: absolute;
  left: 14px;
  right: 14px;
  bottom: 0;
  height: 2px;
  background: var(--grad-primary);
  border-radius: 2px;
  box-shadow: 0 0 10px rgba(72, 230, 199, .42);
}

.topbar-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  min-width: 128px;
  min-height: 36px;
  justify-content: flex-end;
}
.topbar-credit {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  height: 32px;
  padding: 0 14px;
  background: rgba(72, 230, 199, .09);
  color: var(--accent-primary-2);
  border: 1px solid rgba(72, 230, 199, .22);
  border-radius: var(--radius-pill);
  font-size: 13px;
  font-weight: 700;
  min-width: 78px;
  justify-content: center;
}
.topbar-credit.is-loading,
.topbar-avatar.is-loading {
  opacity: .62;
}

.topbar-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--grad-primary);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text-on-accent);
  font-weight: 700;
  cursor: pointer;
  transition: transform var(--dur-base) var(--ease-out), box-shadow var(--dur-base) var(--ease-out);
  border: 2px solid transparent;
}
.topbar-avatar:hover {
  transform: scale(1.08);
  box-shadow: var(--shadow-glow);
}
.topbar-avatar:focus-visible {
  outline: none;
  border-color: var(--accent-cyan);
}

.topbar-mobile-toggle {
  display: none;
  width: 36px;
  height: 36px;
  align-items: center;
  justify-content: center;
  color: var(--text-primary);
  border-radius: var(--radius-sm);
  transition: background var(--dur-base) var(--ease-out), transform var(--dur-base) var(--ease-out);
}
.topbar-mobile-toggle:hover { background: rgba(255,255,255,.055); transform: translateY(-1px); }

@media (max-width: 960px) {
  .topbar-nav { display: none; }
  .topbar-mobile-toggle { display: inline-flex; }
}

/* dropdown menu */
.topbar-menu {
  position: absolute;
  top: 56px;
  right: var(--space-6);
  z-index: var(--z-popover);
  min-width: 220px;
  padding: 8px;
  background: var(--bg-overlay);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  animation: dropdownIn 200ms var(--ease-spring);
}
.topbar-menu-header {
  padding: 10px 12px;
  color: var(--text-secondary);
  font-size: 12px;
  border-bottom: 1px solid var(--border-subtle);
  margin-bottom: 6px;
}
.topbar-menu-item {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 10px 12px;
  background: transparent;
  color: var(--text-primary);
  font-size: 14px;
  border-radius: var(--radius-sm);
  text-align: left;
  text-decoration: none;
  cursor: pointer;
  transition: background var(--dur-base) var(--ease-out);
}
.topbar-menu-item.is-danger { color: var(--danger); }
.topbar-menu-item:hover { background: rgba(72, 230, 199, .11); color: var(--text-primary); }
.topbar-menu-item.is-danger:hover { background: rgba(255, 125, 144, .12); }

@keyframes dropdownIn {
  from { opacity: 0; transform: translateY(-8px); }
  to   { opacity: 1; transform: translateY(0); }
}