:root {
  --shell-canvas: var(--ui-canvas, #0d141b);
  --shell-surface: var(--ui-surface, #121c25);
  --shell-surface-raised: var(--ui-surface-raised, #18242d);
  --shell-text: var(--ui-text, #f4f7f9);
  --shell-muted: var(--ui-muted, #a7b3bb);
  --shell-border: var(--ui-border, #33434e);
  --shell-accent: var(--ui-accent, #8fcbe8);
  --shell-focus: var(--ui-focus, #f1d269);
  --shell-target: var(--ui-control-height, 44px);
  --shell-radius-sm: 6px;
  --shell-radius-md: 8px;
  --shell-header-height: 64px;
  --shell-gutter: 18px;
  --shell-space-1: 4px;
  --shell-space-2: 8px;
  --shell-space-3: 12px;
  --shell-space-4: 16px;
}

.portal-app {
  min-height: 100dvh;
  background-color: var(--shell-canvas);
  color: var(--shell-text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  letter-spacing: 0;
  text-rendering: optimizeLegibility;
}

.portal-app .app-shell-header {
  min-height: var(--shell-header-height);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--shell-space-4);
  padding:
    calc(var(--shell-space-2) + env(safe-area-inset-top))
    max(var(--shell-gutter), env(safe-area-inset-right))
    var(--shell-space-2)
    max(var(--shell-gutter), env(safe-area-inset-left));
  border-bottom: 1px solid var(--shell-border);
  background-color: var(--shell-surface);
  color: var(--shell-text);
}

.portal-app .app-shell-brand,
.portal-app .app-shell-nav,
.portal-app .app-shell-breadcrumb,
.portal-app .app-shell-tools {
  display: flex;
  align-items: center;
  min-width: 0;
}

.portal-app .app-shell-brand {
  gap: var(--shell-space-3);
}

.portal-app .app-shell-nav,
.portal-app .app-shell-breadcrumb {
  gap: var(--shell-space-2);
}

.portal-app .app-shell-tools {
  gap: var(--shell-space-2);
}

.portal-app .app-shell-back,
.portal-app .app-shell-action,
.portal-app .app-shell-breadcrumb a {
  min-height: var(--shell-target);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--shell-radius-md);
  color: var(--shell-accent);
  text-decoration: none;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.portal-app .app-shell-back {
  flex: 0 0 auto;
  min-width: var(--shell-target);
  padding: 0 var(--shell-space-2);
}

.portal-app .app-shell-back--icon,
.portal-app .app-shell-action {
  width: var(--shell-target);
  min-width: var(--shell-target);
  height: var(--shell-target);
  padding: 0;
}

.portal-app .app-shell-title {
  min-width: 0;
}

.portal-app .app-shell-heading,
.portal-app .app-shell-page-title {
  color: var(--shell-text);
  letter-spacing: 0;
}

.portal-app .app-shell-header .app-shell-heading {
  margin: 0;
  overflow: hidden;
  font-size: 20px;
  line-height: 1.25;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.portal-app .app-shell-page-title {
  margin-top: 0;
  line-height: 1.2;
}

.portal-app .app-shell-kicker {
  margin-top: 0;
  margin-bottom: 2px;
  color: var(--shell-accent);
  font-size: 11px;
  font-weight: 650;
  letter-spacing: 0;
}

.portal-app .app-shell-meta {
  min-width: 0;
  color: var(--shell-muted);
  font-variant-numeric: tabular-nums;
}

.portal-app .app-shell-divider {
  flex: 0 0 auto;
  color: var(--shell-muted);
  opacity: 0.65;
}

.portal-app .app-shell-current {
  min-width: 0;
  overflow: hidden;
  color: var(--shell-text);
  text-overflow: ellipsis;
  white-space: nowrap;
}

.portal-app :where(a, button, input, select, textarea, [tabindex]):focus-visible {
  outline: 2px solid var(--shell-focus);
  outline-offset: 3px;
}

.portal-app :where(button, input, select, textarea) {
  font: inherit;
}

.portal-app :where(button, input, select, textarea):disabled {
  cursor: not-allowed;
}

@media (hover: hover) {
  .portal-app .app-shell-back:hover,
  .portal-app .app-shell-action:hover,
  .portal-app .app-shell-breadcrumb a:hover {
    color: var(--shell-text);
  }
}

@media (max-width: 640px) {
  :root {
    --shell-gutter: 14px;
    --shell-space-4: 10px;
  }

  .portal-app .app-shell-header {
    padding-top: calc(var(--shell-space-2) + env(safe-area-inset-top));
  }

  .portal-app .reader-header.app-shell-header {
    align-items: center;
    gap: var(--shell-space-2);
  }

  .portal-app .reader-header .app-shell-tools {
    max-width: calc(100% - 52px);
    overflow-x: auto;
    overscroll-behavior-inline: contain;
    scrollbar-width: none;
  }

  .portal-app .reader-header .app-shell-tools::-webkit-scrollbar {
    display: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  .portal-app *,
  .portal-app *::before,
  .portal-app *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}