:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --ink: #0f172a;
  --muted: #64748b;
  --line: #e2e8f0;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family:
    ui-sans-serif,
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    "Microsoft YaHei",
    "PingFang SC",
    "Noto Sans CJK SC",
    sans-serif;
  text-rendering: optimizeLegibility;
}

.skip-link {
  position: fixed;
  left: 1rem;
  top: 1rem;
  z-index: 100;
  transform: translateY(-140%);
  border-radius: 6px;
  background: var(--ink);
  color: #fff;
  padding: 0.6rem 0.9rem;
  font-size: 0.875rem;
  transition: transform 160ms ease;
}

.skip-link:focus {
  transform: translateY(0);
  outline: 3px solid rgba(37, 99, 235, 0.35);
}

.brand-mark {
  display: inline-grid;
  width: 2.25rem;
  height: 2.25rem;
  place-items: center;
  border: 1px solid rgba(37, 99, 235, 0.18);
  border-radius: 8px;
  background: #eff6ff;
  color: var(--primary);
}

.brand-mark svg {
  width: 1.25rem;
  height: 1.25rem;
}

.nav-link,
.mobile-nav-link,
.footer-link {
  transition:
    color 160ms ease,
    background-color 160ms ease,
    border-color 160ms ease;
}

.nav-link {
  border-radius: 6px;
  color: #475569;
  font-size: 0.925rem;
  font-weight: 600;
  padding: 0.55rem 0.75rem;
}

.nav-link:hover,
.nav-link[aria-current="page"] {
  background: #eff6ff;
  color: var(--primary);
}

.mobile-nav-link {
  border-radius: 8px;
  color: #334155;
  font-weight: 600;
  padding: 0.8rem 0.9rem;
}

.mobile-nav-link:hover,
.mobile-nav-link[aria-current="page"] {
  background: #eff6ff;
  color: var(--primary);
}

.footer-link:hover {
  color: var(--primary);
}

.btn,
.icon-button {
  align-items: center;
  border-radius: 8px;
  display: inline-flex;
  font-weight: 700;
  justify-content: center;
  transition:
    background-color 160ms ease,
    border-color 160ms ease,
    color 160ms ease,
    transform 160ms ease,
    box-shadow 160ms ease;
}

.btn {
  gap: 0.45rem;
  min-height: 2.5rem;
  padding: 0.64rem 1rem;
  white-space: nowrap;
}

.btn-lg {
  min-height: 3rem;
  padding: 0.8rem 1.15rem;
}

.btn:hover {
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 12px 30px rgba(37, 99, 235, 0.22);
}

.btn-primary:hover {
  background: var(--primary-dark);
}

.btn-secondary,
.btn-quiet {
  border: 1px solid var(--line);
  background: #fff;
  color: #1e293b;
}

.btn-secondary:hover,
.btn-quiet:hover {
  border-color: rgba(37, 99, 235, 0.35);
  color: var(--primary);
}

.icon-button {
  width: 2.5rem;
  height: 2.5rem;
  border: 1px solid var(--line);
  background: #fff;
  color: #1e293b;
}

.icon-button:hover {
  border-color: rgba(37, 99, 235, 0.35);
  color: var(--primary);
}

.hero-surface {
  background:
    linear-gradient(180deg, #f8fbff 0%, #ffffff 100%),
    repeating-linear-gradient(90deg, rgba(37, 99, 235, 0.06) 0 1px, transparent 1px 72px);
}

.hero-panel {
  overflow: hidden;
  border: 1px solid rgba(148, 163, 184, 0.28);
  border-radius: 8px;
  background: #fff;
  box-shadow: 0 28px 80px rgba(15, 23, 42, 0.12);
}

.hero-panel-top {
  display: flex;
  gap: 0.45rem;
  border-bottom: 1px solid #e2e8f0;
  background: #f8fafc;
  padding: 0.85rem 1rem;
}

.hero-panel-top span {
  width: 0.7rem;
  height: 0.7rem;
  border-radius: 999px;
  background: #cbd5e1;
}

.hero-panel-top span:first-child {
  background: #60a5fa;
}

.upload-preview {
  align-items: center;
  border: 1px dashed rgba(37, 99, 235, 0.42);
  border-radius: 8px;
  background: #eff6ff;
  display: flex;
  gap: 1rem;
  padding: 1rem;
}

.file-row {
  align-items: center;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  display: flex;
  gap: 0.85rem;
  padding: 0.85rem;
}

.file-icon {
  align-items: center;
  background: #dbeafe;
  border-radius: 6px;
  color: var(--primary);
  display: inline-flex;
  flex: 0 0 auto;
  font-size: 0.7rem;
  font-weight: 800;
  height: 2rem;
  justify-content: center;
  letter-spacing: 0;
  width: 2.4rem;
}

.file-icon-cyan {
  background: #cffafe;
  color: #0891b2;
}

.quick-action {
  align-items: center;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  color: #334155;
  display: flex;
  font-size: 0.875rem;
  font-weight: 700;
  gap: 0.55rem;
  justify-content: center;
  min-height: 3rem;
}

.metric {
  border-left: 3px solid rgba(37, 99, 235, 0.72);
  padding-left: 1rem;
}

.metric dt {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
}

.metric dd {
  color: var(--ink);
  font-size: 1.05rem;
  font-weight: 800;
  margin-top: 0.25rem;
}

.section {
  padding-bottom: 5rem;
  padding-top: 5rem;
}

.section-heading {
  margin-left: auto;
  margin-right: auto;
  max-width: 42rem;
  text-align: center;
}

.section-heading h2 {
  color: var(--ink);
  font-size: clamp(2rem, 4vw, 2.65rem);
  font-weight: 700;
  letter-spacing: 0;
  line-height: 1.18;
}

.section-heading p {
  color: var(--muted);
  font-size: 1rem;
  line-height: 1.8;
  margin-top: 1rem;
}

.tool-card,
.benefit-item,
.step-item,
.faq-item {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  background: #fff;
}

.tool-card {
  color: inherit;
  display: flex;
  flex-direction: column;
  min-height: 17.5rem;
  padding: 1.25rem;
  transition:
    border-color 160ms ease,
    box-shadow 160ms ease,
    transform 160ms ease;
}

.tool-card:hover {
  border-color: rgba(37, 99, 235, 0.35);
  box-shadow: 0 18px 50px rgba(15, 23, 42, 0.10);
  transform: translateY(-3px);
}

.tool-icon,
.benefit-icon {
  align-items: center;
  border-radius: 8px;
  display: inline-flex;
  height: 3rem;
  justify-content: center;
  width: 3rem;
}

.tool-icon svg,
.benefit-icon svg {
  height: 1.45rem;
  width: 1.45rem;
}

.tool-card h3,
.benefit-item h3,
.step-item h3 {
  color: var(--ink);
  font-size: 1.15rem;
  font-weight: 800;
  margin-top: 1rem;
}

.tool-card p,
.benefit-item p,
.step-item p {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.72;
  margin-top: 0.75rem;
}

.tool-link {
  align-items: center;
  color: var(--primary);
  display: inline-flex;
  font-size: 0.92rem;
  font-weight: 800;
  margin-top: auto;
  padding-top: 1.25rem;
}

.benefit-item {
  padding: 1.2rem;
}

.step-item {
  padding: 1.35rem;
}

.step-item span {
  align-items: center;
  background: #eff6ff;
  border-radius: 999px;
  color: var(--primary);
  display: inline-flex;
  font-weight: 900;
  height: 2.25rem;
  justify-content: center;
  width: 2.25rem;
}

.faq-list {
  display: grid;
  gap: 0.85rem;
}

.faq-item {
  overflow: hidden;
}

.faq-question {
  align-items: center;
  color: var(--ink);
  display: flex;
  font-weight: 800;
  gap: 1rem;
  justify-content: space-between;
  line-height: 1.45;
  padding: 1rem 1.1rem;
  text-align: left;
  width: 100%;
}

.faq-icon {
  border-radius: 999px;
  flex: 0 0 auto;
  height: 1.5rem;
  position: relative;
  width: 1.5rem;
}

.faq-icon::before,
.faq-icon::after {
  background: var(--primary);
  content: "";
  left: 50%;
  position: absolute;
  top: 50%;
  transform: translate(-50%, -50%);
}

.faq-icon::before {
  height: 2px;
  width: 0.85rem;
}

.faq-icon::after {
  height: 0.85rem;
  width: 2px;
}

.faq-item.is-open .faq-icon::after {
  opacity: 0;
}

.faq-panel {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.78;
  max-height: 0;
  overflow: hidden;
  transition: max-height 220ms ease;
}

.faq-panel p {
  padding: 0 1.1rem 1rem;
}

.faq-item.is-open .faq-panel {
  max-height: 14rem;
}

.ad-unit {
  min-height: 90px;
  width: 100%;
}

.adsbygoogle[data-ad-client*="XXXXXXXXXXXXXXXX"] {
  display: none !important;
  min-height: 0;
}

.tool-layout {
  align-items: start;
  display: grid;
  gap: 1.5rem;
  grid-template-columns: minmax(0, 1fr);
}

.tool-panel,
.tool-aside,
.result-card,
.notice-card {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  background: #fff;
}

.tool-panel {
  box-shadow: 0 18px 50px rgba(15, 23, 42, 0.08);
}

.tool-panel-header {
  border-bottom: 1px solid #e2e8f0;
  padding: 1.25rem;
}

.tool-panel-body {
  padding: 1.25rem;
}

.drop-zone {
  align-items: center;
  border: 2px dashed rgba(37, 99, 235, 0.35);
  border-radius: 8px;
  background: #eff6ff;
  color: #1e293b;
  display: grid;
  gap: 0.85rem;
  justify-items: center;
  min-height: 13rem;
  padding: 1.5rem;
  text-align: center;
  transition:
    background-color 160ms ease,
    border-color 160ms ease,
    transform 160ms ease;
}

.drop-zone.is-dragover {
  border-color: var(--primary);
  background: #dbeafe;
  transform: translateY(-1px);
}

.drop-zone-icon {
  align-items: center;
  background: #fff;
  border: 1px solid rgba(37, 99, 235, 0.18);
  border-radius: 8px;
  color: var(--primary);
  display: inline-flex;
  height: 3.5rem;
  justify-content: center;
  width: 3.5rem;
}

.drop-zone-icon svg {
  height: 1.6rem;
  width: 1.6rem;
}

.file-list {
  display: grid;
  gap: 0.75rem;
}

.merge-file-row {
  align-items: center;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  display: grid;
  gap: 0.9rem;
  grid-template-columns: auto minmax(0, 1fr) auto;
  padding: 0.85rem;
}

.merge-file-row[draggable="true"] {
  cursor: grab;
}

.merge-file-row.is-dragging {
  border-color: rgba(37, 99, 235, 0.45);
  opacity: 0.62;
}

.drag-handle {
  align-items: center;
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 6px;
  color: #64748b;
  display: inline-flex;
  height: 2rem;
  justify-content: center;
  width: 2rem;
}

.file-actions {
  display: flex;
  gap: 0.35rem;
}

.mini-button {
  align-items: center;
  border: 1px solid #e2e8f0;
  border-radius: 6px;
  color: #475569;
  display: inline-flex;
  font-size: 0.78rem;
  font-weight: 800;
  height: 2rem;
  justify-content: center;
  min-width: 2rem;
  padding: 0 0.55rem;
  transition:
    background-color 160ms ease,
    border-color 160ms ease,
    color 160ms ease;
}

.mini-button:hover:not(:disabled) {
  border-color: rgba(37, 99, 235, 0.35);
  color: var(--primary);
}

.mini-button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

.progress-track {
  --progress: 0%;
  height: 0.65rem;
  overflow: hidden;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--primary) 0 var(--progress), #e2e8f0 var(--progress) 100%);
  position: relative;
}

.progress-fill {
  display: none;
}

.status-banner {
  border-radius: 8px;
  font-size: 0.92rem;
  line-height: 1.65;
  padding: 0.85rem 1rem;
}

.status-banner.info {
  background: #eff6ff;
  color: #1d4ed8;
}

.status-banner.warning {
  background: #fffbeb;
  color: #92400e;
}

.status-banner.error {
  background: #fef2f2;
  color: #b91c1c;
}

.result-card,
.notice-card,
.tool-aside {
  padding: 1.2rem;
}

.result-card {
  display: none;
}

.result-card.is-visible {
  display: block;
}

.aside-list {
  display: grid;
  gap: 0.75rem;
}

.aside-list li {
  color: #475569;
  font-size: 0.93rem;
  line-height: 1.65;
  padding-left: 1.4rem;
  position: relative;
}

.aside-list li::before {
  background: var(--primary);
  border-radius: 999px;
  content: "";
  height: 0.45rem;
  left: 0.2rem;
  position: absolute;
  top: 0.65rem;
  width: 0.45rem;
}

.form-grid {
  display: grid;
  gap: 1rem;
}

.form-field {
  display: grid;
  gap: 0.45rem;
}

.form-label {
  color: var(--ink);
  font-size: 0.92rem;
  font-weight: 800;
}

.form-help {
  color: var(--muted);
  font-size: 0.85rem;
  line-height: 1.65;
}

.text-input,
.select-input {
  border: 1px solid #cbd5e1;
  border-radius: 8px;
  color: var(--ink);
  font-size: 0.95rem;
  min-height: 2.75rem;
  padding: 0.72rem 0.85rem;
  transition:
    border-color 160ms ease,
    box-shadow 160ms ease;
  width: 100%;
}

.text-input:focus,
.select-input:focus {
  border-color: rgba(37, 99, 235, 0.75);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.14);
  outline: none;
}

.choice-row {
  align-items: center;
  display: flex;
  gap: 0.65rem;
}

.choice-row input {
  accent-color: var(--primary);
  height: 1rem;
  width: 1rem;
}

.result-list {
  display: grid;
  gap: 0.75rem;
}

.result-row {
  align-items: center;
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  display: grid;
  gap: 0.9rem;
  grid-template-columns: minmax(0, 1fr) auto;
  padding: 0.9rem;
}

.page-grid {
  display: grid;
  gap: 0.85rem;
  grid-template-columns: repeat(auto-fill, minmax(9.5rem, 1fr));
}

.page-card {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  background: #fff;
  cursor: grab;
  display: grid;
  gap: 0.85rem;
  padding: 0.85rem;
  transition:
    border-color 160ms ease,
    opacity 160ms ease,
    transform 160ms ease;
}

.page-card.is-dragging {
  opacity: 0.6;
}

.page-card.is-removed {
  border-color: #fecaca;
  background: #fef2f2;
  opacity: 0.68;
}

.page-preview {
  align-items: center;
  aspect-ratio: 3 / 4;
  background: linear-gradient(180deg, #f8fafc 0%, #eff6ff 100%);
  border: 1px solid #dbeafe;
  border-radius: 6px;
  color: var(--primary);
  display: grid;
  font-size: 1.55rem;
  font-weight: 900;
  justify-items: center;
  position: relative;
}

.page-preview small {
  bottom: 0.65rem;
  color: #64748b;
  font-size: 0.72rem;
  font-weight: 800;
  position: absolute;
}

.page-actions {
  display: grid;
  gap: 0.45rem;
  grid-template-columns: repeat(2, 1fr);
}

.content-shell {
  margin-left: auto;
  margin-right: auto;
  max-width: 58rem;
}

.article-content {
  color: #334155;
  font-size: 1rem;
  line-height: 1.85;
}

.article-content h2 {
  color: var(--ink);
  font-size: 1.6rem;
  font-weight: 800;
  line-height: 1.3;
  margin-top: 2.5rem;
}

.article-content h3 {
  color: var(--ink);
  font-size: 1.15rem;
  font-weight: 800;
  margin-top: 1.5rem;
}

.article-content p,
.article-content ul {
  margin-top: 1rem;
}

.article-content ul {
  display: grid;
  gap: 0.5rem;
  list-style: disc;
  padding-left: 1.25rem;
}

.article-card {
  border: 1px solid #e2e8f0;
  border-radius: 8px;
  background: #fff;
  padding: 1.35rem;
}

@media (min-width: 1024px) {
  [data-menu-toggle] {
    display: none;
  }

  .tool-layout {
    grid-template-columns: minmax(0, 1fr) 22rem;
  }
}

@media (max-width: 640px) {
  .section {
    padding-bottom: 3.5rem;
    padding-top: 3.5rem;
  }

  .btn {
    width: 100%;
  }

  .tool-card {
    min-height: auto;
  }

  .ad-unit {
    min-height: 72px;
  }

  .merge-file-row {
    grid-template-columns: auto minmax(0, 1fr);
  }

  .file-actions {
    grid-column: 1 / -1;
  }

  .result-row {
    grid-template-columns: 1fr;
  }

  .page-grid {
    grid-template-columns: repeat(auto-fill, minmax(8.25rem, 1fr));
  }
}

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