/* Critical first-paint styles for the SPA shell. The full app stylesheet loads async. */
:root {
  --bg: #fafaf9;
  --surface: #ffffff;
  --surface-2: #f4f4f2;
  --ink: #0f172a;
  --ink-2: #1e293b;
  --on-ink: #ffffff;
  --muted: #64748b;
  --faint: #94a3b8;
  --border: #e7e5e0;
  --border-strong: #d6d3ce;
  --accent: #e11d48;
  --accent-2: #be123c;
  --accent-soft: #fff1f3;
  --accent-border: #fecdd3;
  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow: 0 1px 3px rgba(15, 23, 42, 0.06), 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.06), 0 2px 4px -2px rgba(15, 23, 42, 0.04);
  --radius-sm: 8px;
  --radius: 12px;
  --radius-pill: 999px;
  --sans: "Inter", -apple-system, "Segoe UI", system-ui, sans-serif;
  --sans-cn: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

:root[data-theme="dark"],
:root[data-theme="dark"] body {
  --bg: #0b0b0f;
  --surface: #16161d;
  --surface-2: #1f1f29;
  --ink: #f1f5f9;
  --ink-2: #e2e8f0;
  --on-ink: #0b0b0f;
  --muted: #94a3b8;
  --faint: #64748b;
  --border: #2a2a36;
  --border-strong: #3a3a48;
  --accent: #fb7185;
  --accent-2: #f43f5e;
  --accent-soft: #2a1218;
  --accent-border: #4a1f29;
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --bg: #0b0b0f;
    --surface: #16161d;
    --surface-2: #1f1f29;
    --ink: #f1f5f9;
    --ink-2: #e2e8f0;
    --on-ink: #0b0b0f;
    --muted: #94a3b8;
    --faint: #64748b;
    --border: #2a2a36;
    --border-strong: #3a3a48;
    --accent: #fb7185;
    --accent-2: #f43f5e;
    --accent-soft: #2a1218;
    --accent-border: #4a1f29;
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.4), 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5), 0 2px 4px -2px rgba(0, 0, 0, 0.4);
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: var(--sans);
  font-feature-settings: "cv11", "ss01";
  background: var(--bg);
  color: var(--ink);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
:lang(zh), .hz { font-family: var(--sans-cn); }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 28px;
  background: color-mix(in srgb, var(--surface) 80%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 30;
  gap: 12px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  color: var(--ink);
  text-decoration: none;
  user-select: none;
}
.brand-logo {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: linear-gradient(135deg, var(--accent), #f43f5e);
  color: #fff;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--sans-cn);
  font-weight: 700;
  font-size: 16px;
  box-shadow: 0 2px 6px rgba(225, 29, 72, 0.35);
}
.brand-text {
  display: flex;
  align-items: baseline;
  gap: 8px;
  line-height: 1;
}
.brand-name {
  font-weight: 700;
  font-size: 16px;
  letter-spacing: 0;
  color: var(--ink);
}
.brand-name-cn {
  font-family: var(--sans-cn);
  font-weight: 500;
  font-size: 14px;
  color: var(--faint);
}
.nav {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: flex-end;
}
.nav-group {
  display: inline-flex;
  align-items: center;
  gap: 2px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  padding: 4px;
  border-radius: var(--radius-pill);
}
.nav-group button,
.nav-group .nav-link {
  background: transparent;
  border: 0;
  padding: 7px 14px;
  font-family: var(--sans);
  font-size: 13.5px;
  font-weight: 500;
  color: var(--muted);
  cursor: pointer;
  border-radius: var(--radius-pill);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  white-space: nowrap;
}
.nav-group button:hover,
.nav-group .nav-link:hover { color: var(--ink); background: color-mix(in srgb, var(--surface) 60%, transparent); }
.nav-group button.is-active,
.nav-group .nav-link.is-active {
  color: var(--ink);
  background: var(--surface);
  box-shadow: var(--shadow-xs);
}

#theme-btn, .icon-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-size: 14px;
  color: var(--muted);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0;
}
#auth-area {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.topbar-search {
  position: relative;
  display: inline-flex;
  align-items: center;
  width: clamp(150px, 16vw, 230px);
}
.topbar-search input {
  width: 100%;
  height: 34px;
  padding: 7px 12px 7px 34px;
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  background: var(--surface);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 13px;
  box-shadow: var(--shadow-xs);
}
.topbar-search input::placeholder { color: var(--faint); }
.topbar-search::before {
  content: "";
  position: absolute;
  left: 12px;
  top: 50%;
  width: 14px;
  height: 14px;
  background: var(--faint);
  transform: translateY(-50%);
  pointer-events: none;
  -webkit-mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><circle cx='11' cy='11' r='8'/><path d='m21 21-4.3-4.3'/></svg>") center / contain no-repeat;
          mask: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='currentColor' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'><circle cx='11' cy='11' r='8'/><path d='m21 21-4.3-4.3'/></svg>") center / contain no-repeat;
}
.pro-chip {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 30px;
  padding: 5px 12px;
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-pill);
  background: var(--accent-soft);
  color: var(--accent-2);
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 800;
  cursor: pointer;
  box-shadow: var(--shadow-xs);
}
.topbar-internal-status,
#auth-status.topbar-internal-status:not(:empty) { display: none !important; }
.auth-signin {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--ink);
  color: var(--on-ink);
  border: 1px solid var(--ink);
  border-radius: var(--radius-sm);
  padding: 7px 14px 7px 12px;
  font-family: var(--sans);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
}
.auth-signin .g-icon {
  background: #fff;
  padding: 2px;
  border-radius: 3px;
  flex: 0 0 18px;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 48px 28px 96px;
}
.hero {
  text-align: center;
  padding: 12px 12px 32px;
}
.hero h1 {
  font-size: 48px;
  font-weight: 800;
  letter-spacing: 0;
  line-height: 1.05;
  margin: 0 0 14px;
  color: var(--ink);
}
.hero p {
  font-size: 18px;
  color: var(--muted);
  margin: 0 auto;
  max-width: 560px;
  line-height: 1.55;
}
.hero-actions {
  margin-top: 24px;
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
}
.library-hero .hero-actions {
  margin: 28px auto 0;
}
.ctrl-btn {
  font-family: var(--sans);
  font-size: 14px;
  font-weight: 600;
  padding: 9px 18px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: 1px solid var(--ink);
  background: var(--ink);
  color: var(--on-ink);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  letter-spacing: 0;
  text-decoration: none;
}
.ctrl-btn.secondary {
  background: var(--surface);
  color: var(--ink);
  border-color: var(--border);
  box-shadow: var(--shadow-xs);
}
.library-hero .hero-actions .ctrl-btn {
  justify-content: center;
  min-height: 54px;
  min-width: min(100%, 300px);
  padding: 15px 24px;
  border-radius: 12px;
  font-size: 15px;
  box-shadow: var(--shadow);
}
.library-hero #hero-start-story {
  background: linear-gradient(135deg, var(--ink), var(--ink-2));
  border-color: var(--ink);
}
.hero-secondary-actions {
  margin: 12px auto 0;
  display: flex;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
}
.hero-secondary-actions .ctrl-btn {
  min-height: 40px;
  padding: 9px 14px;
  border-color: var(--border-strong);
  background: color-mix(in srgb, var(--surface) 78%, transparent);
  color: var(--ink-2);
  box-shadow: none;
}
.reader-preview {
  width: min(100%, 720px);
  margin: 30px auto 0;
  text-align: left;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}
.reader-preview-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 11px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--surface-2);
}
.reader-preview-title {
  color: var(--muted);
  font-size: 12px;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: .08em;
}
.reader-preview-level {
  padding: 3px 9px;
  border-radius: var(--radius-pill);
  background: var(--accent-soft);
  color: var(--accent-2);
  border: 1px solid var(--accent-border);
  font-size: 12px;
  font-weight: 800;
}
.reader-preview-body {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 170px;
  gap: 14px;
  padding: 18px;
}
.reader-preview-sentence {
  grid-column: 1;
  display: grid;
  grid-template-columns: 120px minmax(0, 1fr) 110px;
  align-items: center;
  gap: 12px;
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  color: var(--ink);
}
.reader-preview-sentence.active {
  background: var(--accent-soft);
  outline: 1px solid var(--accent-border);
}
.preview-py {
  color: var(--muted);
  font-size: 13px;
  font-weight: 700;
}
.preview-hz {
  font-family: var(--sans-cn);
  font-size: 24px;
  font-weight: 700;
  line-height: 1.2;
}
.preview-en {
  color: var(--muted);
  font-size: 13px;
  text-align: right;
}
.reader-preview-popover {
  grid-column: 2;
  grid-row: 1 / span 2;
  align-self: center;
  display: grid;
  gap: 4px;
  padding: 14px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-sm);
  background: var(--surface);
  box-shadow: var(--shadow-md);
}
.reader-preview-popover strong {
  font-family: var(--sans-cn);
  font-size: 28px;
  line-height: 1;
}
.reader-preview-popover span {
  color: var(--accent-2);
  font-weight: 800;
}
.reader-preview-popover small {
  color: var(--muted);
  font-size: 13px;
}
.fallback-content {
  max-width: 920px;
  margin: 0 auto;
}
.fallback-content h2 {
  margin: 0 0 14px;
  font-size: 22px;
  letter-spacing: 0;
  color: var(--ink);
}
.fallback-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}
.fallback-card {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 118px;
  padding: 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink);
  text-decoration: none;
  box-shadow: var(--shadow-xs);
}
.fallback-card strong {
  font-size: 15px;
  line-height: 1.3;
}
.fallback-card span,
.no-js-note {
  color: var(--muted);
  font-size: 13.5px;
  line-height: 1.5;
}
.no-js-note {
  margin: 18px 0 0;
  padding: 12px 14px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  background: var(--surface-2);
}
.hidden { display: none !important; }

@media (max-width: 768px) {
  .topbar { padding: 12px 0 10px; flex-wrap: wrap; gap: 10px; }
  .brand { margin: 0 16px; }
  .nav { width: 100%; justify-content: center; gap: 8px; padding: 0 16px; }
  .nav-group {
    order: -1;
    flex: 1 0 calc(100% + 32px);
    max-width: calc(100% + 32px);
    margin: 0 -16px;
    padding: 6px 16px;
    gap: 6px;
    overflow-x: auto;
    border-left: 0;
    border-right: 0;
    border-radius: 0;
    background: var(--surface);
    box-shadow: inset 0 1px 0 color-mix(in srgb, var(--ink) 6%, transparent), inset 0 -1px 0 color-mix(in srgb, var(--ink) 7%, transparent);
    scroll-padding: 16px;
    scroll-snap-type: x proximity;
    scrollbar-width: none;
    -webkit-overflow-scrolling: touch;
  }
  .nav-group::-webkit-scrollbar { display: none; }
  .nav-group button,
  .nav-group .nav-link {
    flex: 0 0 auto;
    min-height: 36px;
    padding: 8px 13px;
    border-radius: var(--radius-sm);
    color: var(--ink-2);
    font-size: 14px;
    font-weight: 700;
    scroll-snap-align: start;
  }
  .nav-group button.is-active,
  .nav-group .nav-link.is-active {
    color: var(--on-ink);
    background: var(--ink);
    box-shadow: var(--shadow);
  }
  main { padding: 32px 16px 64px; }
  .hero h1 { font-size: 36px; }
  .hero p { font-size: 16px; }
  .library-hero { padding-top: 6px; }
  .library-hero .hero-actions .ctrl-btn {
    width: min(100%, 360px);
    min-height: 48px;
    padding: 12px 14px;
    font-size: 14px;
  }
  .hero-secondary-actions {
    max-width: 360px;
    gap: 8px;
  }
  .hero-secondary-actions .ctrl-btn {
    flex: 1 1 calc(50% - 8px);
    justify-content: center;
  }
  .topbar-search {
    order: 1;
    flex: 1 1 180px;
    max-width: 260px;
  }
  .reader-preview {
    margin-top: 24px;
    border-radius: var(--radius-sm);
  }
  .reader-preview-body {
    grid-template-columns: 1fr;
    gap: 10px;
    padding: 12px;
  }
  .reader-preview-sentence {
    grid-template-columns: 1fr;
    gap: 3px;
    padding: 11px 12px;
  }
  .preview-hz { font-size: 22px; }
  .preview-en { text-align: left; }
  .reader-preview-popover {
    grid-column: 1;
    grid-row: auto;
  }
  .fallback-grid { grid-template-columns: 1fr; }
}