* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, "Microsoft YaHei", sans-serif;
  color: #111827;
  background: #f6f7fb;
  line-height: 1.65;
}

a {
  color: #2563eb;
  text-decoration: none;
  word-break: break-word;
}

.site-header {
  background: #0f172a;
  color: #ffffff;
}

.site-nav,
.site-hero,
.site-main {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
}

.site-nav {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
}

.site-brand {
  color: #ffffff;
  font-size: 22px;
  font-weight: 800;
  letter-spacing: 0.4px;
}

.site-links {
  display: flex;
  align-items: center;
  gap: 18px;
  font-size: 15px;
  flex-wrap: wrap;
}

.site-links a {
  color: #ffffff;
}

.language-select {
  min-height: 36px;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 9px;
  padding: 0 10px;
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  font: inherit;
  cursor: pointer;
}

.language-select option {
  color: #111827;
  background: #ffffff;
}

.site-hero {
  padding: 84px 0 92px;
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 48px;
  align-items: center;
}

.site-hero h1,
.page-title {
  margin: 0;
  font-size: clamp(36px, 6vw, 72px);
  line-height: 1.08;
}

.site-hero h2 {
  margin: 18px 0 0;
  font-size: clamp(22px, 3vw, 32px);
  line-height: 1.25;
  color: #dbeafe;
}

.site-hero p {
  margin: 24px 0 0;
  max-width: 720px;
  color: #e5e7eb;
  font-size: 18px;
}

.site-actions {
  margin-top: 34px;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.site-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 22px;
  border-radius: 10px;
  font-weight: 700;
}

.site-button.primary {
  background: #2563eb;
  color: #ffffff;
}

.site-button.secondary {
  background: rgba(255, 255, 255, 0.12);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.28);
}

.hero-panel,
.content-card {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: 16px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
}

.hero-panel {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.18);
  color: #ffffff;
  padding: 28px;
}

.hero-panel h3 {
  margin: 0 0 14px;
  font-size: 22px;
}

.hero-panel ul {
  margin: 0;
  padding-left: 20px;
  color: #e5e7eb;
}

.site-main {
  padding: 48px 0 56px;
}

.content-card {
  padding: 32px;
}

.section-title {
  margin: 0 0 22px;
  font-size: 30px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.download-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.feature-card,
.contact-item {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: 16px;
  padding: 24px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
}

.feature-card h3 {
  margin: 0 0 10px;
  font-size: 20px;
}

.feature-card p {
  margin: 0;
  color: #4b5563;
}

.download-card {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.download-card h2 {
  margin: 0;
  font-size: 22px;
  line-height: 1.25;
}

.download-card p {
  margin: 0;
}

.download-note {
  color: #6b7280;
  font-size: 14px;
}

.app-store-badge-link {
  display: inline-flex;
  width: fit-content;
  max-width: 100%;
}

.app-store-badge {
  display: block;
  width: min(190px, 100%);
  height: auto;
}

.download-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.site-button.outline {
  color: #2563eb;
  background: #ffffff;
  border: 1px solid #2563eb;
}

.download-footer-links {
  margin-top: 24px;
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  justify-content: center;
}

.page-header {
  background: #0f172a;
  color: #ffffff;
}

.page-header .site-main {
  padding: 44px 0 50px;
}

.page-header p {
  max-width: 720px;
  margin: 16px 0 0;
  color: #dbeafe;
  font-size: 18px;
}

.content-card h2 {
  margin: 28px 0 10px;
  font-size: 22px;
}

.content-card h2:first-child {
  margin-top: 0;
}

.content-card p,
.content-card li {
  font-size: 16px;
}

.content-card ul {
  padding-left: 22px;
}

.updated {
  margin-top: 28px;
  color: #6b7280;
  font-size: 15px;
}

.contact-list {
  display: grid;
  gap: 16px;
  margin-top: 24px;
}

.faq-list {
  display: grid;
  gap: 16px;
  margin-top: 18px;
}

.faq-item {
  padding: 18px;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  background: #f9fafb;
}

.faq-item h3 {
  margin: 0 0 8px;
  font-size: 18px;
}

.faq-item p {
  margin: 0;
}

.contact-label {
  display: block;
  color: #6b7280;
  font-size: 14px;
  margin-bottom: 4px;
}

.contact-value {
  font-size: 18px;
  font-weight: 700;
}

.site-footer {
  border-top: 1px solid #e5e7eb;
  padding: 24px 0;
  text-align: center;
  color: #6b7280;
  font-size: 14px;
}

.site-footer a {
  margin: 0 8px;
}

.help-hero {
  padding-top: 40px;
  padding-bottom: 42px;
}

.help-hero h1 {
  margin: 0;
  font-size: clamp(34px, 5vw, 56px);
  line-height: 1.12;
}

.help-future-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 22px;
}

.help-future-actions button {
  min-height: 38px;
  border: 1px solid rgba(255, 255, 255, 0.28);
  border-radius: 999px;
  padding: 0 14px;
  background: rgba(255, 255, 255, 0.1);
  color: #dbeafe;
  font: inherit;
}

.help-shell {
  display: grid;
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 24px;
  align-items: start;
}

.help-sidebar {
  position: sticky;
  top: 18px;
  max-height: calc(100vh - 36px);
  overflow: auto;
  border: 1px solid #e5e7eb;
  border-radius: 16px;
  background: #ffffff;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
}

.help-toc-toggle {
  width: 100%;
  min-height: 48px;
  border: 0;
  border-bottom: 1px solid #e5e7eb;
  background: #f8fafc;
  color: #111827;
  font: inherit;
  font-weight: 800;
  text-align: left;
  padding: 0 16px;
  cursor: pointer;
}

.help-toc {
  display: grid;
  gap: 8px;
  padding: 14px;
}

.help-toc.collapsed {
  display: none;
}

.help-toc-group {
  display: grid;
  gap: 4px;
}

.help-toc-section,
.help-toc-item {
  display: block;
  border-radius: 10px;
  color: #334155;
}

.help-toc-section {
  padding: 9px 10px;
  font-weight: 800;
}

.help-toc-items {
  display: grid;
  gap: 2px;
  padding-left: 8px;
}

.help-toc-item {
  padding: 7px 10px;
  font-size: 14px;
}

.help-toc a.active {
  background: #dbeafe;
  color: #1d4ed8;
}

.help-content {
  min-width: 0;
  border: 1px solid #e5e7eb;
  border-radius: 16px;
  background: #ffffff;
  padding: 32px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
}

.help-section {
  scroll-margin-top: 22px;
  padding-bottom: 18px;
  border-bottom: 1px solid #e5e7eb;
}

.help-section + .help-section {
  padding-top: 26px;
}

.help-section:last-of-type {
  border-bottom: 0;
}

.help-section h2 {
  margin: 0 0 18px;
  font-size: clamp(24px, 3vw, 34px);
  line-height: 1.25;
}

.help-topic {
  scroll-margin-top: 22px;
  padding: 18px 0;
}

.help-topic h3 {
  margin: 0 0 8px;
  font-size: 21px;
  line-height: 1.3;
}

.help-topic p {
  margin: 8px 0 0;
  color: #4b5563;
}

.help-media-slot {
  margin-top: 14px;
  border: 1px dashed #cbd5e1;
  border-radius: 12px;
  padding: 14px;
  background: #f8fafc;
  color: #64748b;
  font-size: 14px;
}

.help-loading,
.help-error {
  margin: 0;
  color: #6b7280;
}

@media (max-width: 860px) {
  .site-nav {
    min-height: 64px;
    align-items: flex-start;
    flex-direction: column;
    justify-content: center;
    padding: 14px 0;
  }

  .site-links {
    gap: 12px;
    font-size: 14px;
  }

  .site-hero {
    grid-template-columns: 1fr;
    padding: 56px 0 64px;
  }

  .feature-grid,
  .download-grid {
    grid-template-columns: 1fr;
  }

  .help-shell {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .help-sidebar {
    position: static;
    max-height: none;
  }

  .help-toc {
    max-height: 50vh;
    overflow: auto;
  }
}

@media (max-width: 640px) {
  .site-nav,
  .site-hero,
  .site-main {
    width: min(100% - 24px, 1120px);
  }

  .content-card,
  .feature-card,
  .contact-item {
    padding: 22px;
  }

  .help-content {
    padding: 22px;
  }

  .help-topic {
    padding: 14px 0;
  }
}