/* ===== 全局重置 ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--tf-header-height) + 16px);
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.6;
  color: var(--tf-text);
  background-color: var(--tf-bg);
  transition: var(--tf-transition);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--tf-primary); text-decoration: none; transition: var(--tf-transition); }
a:hover { color: var(--tf-primary-dark); }
button { font-family: inherit; cursor: pointer; border: none; background: none; }
ul, ol { list-style: none; }

/* ===== 容器 ===== */
.container {
  max-width: var(--tf-container-max);
  margin: 0 auto;
  padding: 0 24px;
  width: 100%;
}

/* ===== 页面主区域 ===== */
main {
  flex: 1;
  padding-top: var(--tf-header-height);
}

.page-section {
  padding: 80px 0;
}

.page-section:nth-child(even) {
  background-color: var(--tf-bg-secondary);
}

.section-header {
  text-align: center;
  margin-bottom: 56px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--tf-text);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--tf-text-secondary);
  max-width: 640px;
  margin: 0 auto;
}

/* ===== Header ===== */
.app-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--tf-header-height);
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--tf-border-light);
  z-index: 1000;
  transition: var(--tf-transition);
  display: flex;
  align-items: center;
}

.app-header .container {
  height: 100%;
  display: flex;
  align-items: center;
}

[data-theme="dark"] .app-header {
  background-color: rgba(15, 20, 25, 0.85);
}

.app-header.scrolled {
  box-shadow: var(--tf-shadow-sm);
}

.header-inner {
  height: 100%;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--tf-text);
}

.logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--tf-primary) 0%, var(--tf-secondary) 100%);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 1.1rem;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  padding: 8px 16px;
  border-radius: var(--tf-radius-sm);
  color: var(--tf-text-secondary);
  font-weight: 500;
  font-size: 0.95rem;
  transition: var(--tf-transition);
}

.nav-link:hover,
.nav-link.active {
  color: var(--tf-primary);
  background-color: var(--tf-bg-tertiary);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* ===== 按钮 ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  border-radius: var(--tf-radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  transition: var(--tf-transition);
  white-space: nowrap;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: linear-gradient(135deg, var(--tf-primary) 0%, var(--tf-primary-dark) 100%);
  color: white;
  box-shadow: 0 4px 14px rgba(74, 144, 226, 0.35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(74, 144, 226, 0.45);
  color: white;
}

.btn-secondary {
  background-color: var(--tf-bg-tertiary);
  color: var(--tf-text);
}

.btn-secondary:hover {
  background-color: var(--tf-border);
  transform: translateY(-2px);
}

.btn-ghost {
  background: transparent;
  color: var(--tf-text-secondary);
  border: 1px solid var(--tf-border);
}

.btn-ghost:hover {
  border-color: var(--tf-primary);
  color: var(--tf-primary);
}

.btn-lg {
  padding: 16px 32px;
  font-size: 1.05rem;
  border-radius: var(--tf-radius);
}

/* ===== 主题切换 ===== */
.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--tf-bg-tertiary);
  color: var(--tf-text-secondary);
  transition: var(--tf-transition);
}

.theme-toggle:hover {
  background-color: var(--tf-border);
  color: var(--tf-primary);
}

.theme-toggle svg {
  width: 20px;
  height: 20px;
}

/* ===== 移动端菜单 ===== */
.mobile-menu-btn {
  display: none;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  align-items: center;
  justify-content: center;
  background-color: var(--tf-bg-tertiary);
  color: var(--tf-text-secondary);
}

.mobile-menu-btn svg {
  width: 22px;
  height: 22px;
}

.mobile-nav {
  display: none;
  position: fixed;
  top: var(--tf-header-height);
  left: 0;
  right: 0;
  background-color: var(--tf-bg);
  border-bottom: 1px solid var(--tf-border);
  padding: 16px 24px 24px;
  z-index: 999;
  transform: translateY(-10px);
  opacity: 0;
  pointer-events: none;
  transition: var(--tf-transition);
}

.mobile-nav.open {
  transform: translateY(0);
  opacity: 1;
  pointer-events: auto;
}

.mobile-nav-links {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.mobile-nav-links .nav-link {
  padding: 14px 16px;
  font-size: 1rem;
}

/* ===== Hero 首屏 ===== */
.hero {
  padding: 100px 0 80px;
  background:
    radial-gradient(ellipse at top right, rgba(74, 144, 226, 0.12) 0%, transparent 50%),
    radial-gradient(ellipse at bottom left, rgba(255, 107, 107, 0.1) 0%, transparent 50%),
    var(--tf-bg);
  position: relative;
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 14px;
  background-color: var(--tf-bg-tertiary);
  border-radius: 999px;
  font-size: 0.875rem;
  color: var(--tf-primary);
  font-weight: 500;
  margin-bottom: 24px;
}

.hero-badge .dot {
  width: 8px;
  height: 8px;
  background-color: #22C55E;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  background: linear-gradient(135deg, var(--tf-text) 0%, var(--tf-primary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--tf-text-secondary);
  line-height: 1.7;
  margin-bottom: 36px;
  max-width: 520px;
}

.hero-actions {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.hero-features {
  display: flex;
  gap: 24px;
  margin-top: 40px;
  flex-wrap: wrap;
}

.hero-feature {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 0.9rem;
  color: var(--tf-text-secondary);
}

.hero-feature svg {
  width: 18px;
  height: 18px;
  color: #22C55E;
}

/* Hero 视觉 */
.hero-visual {
  position: relative;
}

.hero-phone {
  width: 280px;
  height: 560px;
  margin: 0 auto;
  background: linear-gradient(145deg, var(--tf-bg-card) 0%, var(--tf-bg-secondary) 100%);
  border-radius: 48px;
  padding: 12px;
  box-shadow: var(--tf-shadow-lg), inset 0 0 0 1px var(--tf-border);
  position: relative;
}

.hero-phone::before {
  content: '';
  position: absolute;
  top: 24px;
  left: 50%;
  transform: translateX(-50%);
  width: 80px;
  height: 6px;
  background-color: var(--tf-text-tertiary);
  border-radius: 3px;
  opacity: 0.3;
}

.hero-phone-screen {
  width: 100%;
  height: 100%;
  border-radius: 38px;
  background: linear-gradient(180deg, var(--tf-primary) 0%, var(--tf-secondary) 100%);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  padding: 40px 20px;
  overflow: hidden;
}

.album-art {
  width: 160px;
  height: 160px;
  border-radius: 24px;
  background: rgba(255, 255, 255, 0.2);
  backdrop-filter: blur(10px);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 4rem;
  animation: float 3s ease-in-out infinite;
  box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-12px); }
}

.song-info {
  text-align: center;
  color: white;
}

.song-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.song-artist {
  font-size: 0.85rem;
  opacity: 0.8;
}

.waveform {
  display: flex;
  align-items: center;
  gap: 4px;
  height: 32px;
}

.waveform span {
  display: block;
  width: 4px;
  background-color: rgba(255, 255, 255, 0.8);
  border-radius: 2px;
  animation: wave 1.2s ease-in-out infinite;
}

.waveform span:nth-child(1) { animation-delay: 0s; height: 40%; }
.waveform span:nth-child(2) { animation-delay: 0.1s; height: 70%; }
.waveform span:nth-child(3) { animation-delay: 0.2s; height: 100%; }
.waveform span:nth-child(4) { animation-delay: 0.3s; height: 60%; }
.waveform span:nth-child(5) { animation-delay: 0.4s; height: 85%; }
.waveform span:nth-child(6) { animation-delay: 0.5s; height: 45%; }
.waveform span:nth-child(7) { animation-delay: 0.6s; height: 75%; }
.waveform span:nth-child(8) { animation-delay: 0.7s; height: 55%; }
.waveform span:nth-child(9) { animation-delay: 0.8s; height: 90%; }
.waveform span:nth-child(10) { animation-delay: 0.9s; height: 35%; }

@keyframes wave {
  0%, 100% { transform: scaleY(0.5); }
  50% { transform: scaleY(1); }
}

/* ===== 功能卡片 ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.feature-card {
  background-color: var(--tf-bg-card);
  border-radius: var(--tf-radius-lg);
  padding: 32px 24px;
  transition: var(--tf-transition);
  border: 1px solid var(--tf-border-light);
  position: relative;
  overflow: hidden;
}

.feature-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 3px;
  background: linear-gradient(90deg, var(--tf-primary), var(--tf-secondary));
  opacity: 0;
  transition: var(--tf-transition);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--tf-shadow);
  border-color: var(--tf-border);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  margin-bottom: 20px;
  background: linear-gradient(135deg, rgba(74, 144, 226, 0.12) 0%, rgba(255, 107, 107, 0.1) 100%);
}

.feature-card-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--tf-text);
  margin-bottom: 10px;
}

.feature-card-desc {
  font-size: 0.925rem;
  color: var(--tf-text-secondary);
  line-height: 1.65;
}

/* ===== 截图画廊 ===== */
.screenshot-gallery {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}

.screenshot-card {
  aspect-ratio: 9 / 19;
  border-radius: var(--tf-radius-lg);
  overflow: hidden;
  background-color: var(--tf-bg-card);
  box-shadow: var(--tf-shadow-sm);
  transition: var(--tf-transition);
  cursor: pointer;
  border: 1px solid var(--tf-border-light);
  position: relative;
}

.screenshot-card:hover {
  transform: scale(1.03);
  box-shadow: var(--tf-shadow-lg);
  z-index: 2;
}

.screenshot-placeholder {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 24px;
  text-align: center;
}

.screenshot-placeholder .s-icon {
  font-size: 3rem;
  margin-bottom: 8px;
}

.screenshot-placeholder .s-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--tf-text);
}

.screenshot-placeholder .s-desc {
  font-size: 0.8rem;
  color: var(--tf-text-tertiary);
}

.screenshot-card:nth-child(1) .screenshot-placeholder {
  background: linear-gradient(160deg, #667eea 0%, #764ba2 100%);
}
.screenshot-card:nth-child(2) .screenshot-placeholder {
  background: linear-gradient(160deg, #f093fb 0%, #f5576c 100%);
}
.screenshot-card:nth-child(3) .screenshot-placeholder {
  background: linear-gradient(160deg, #4facfe 0%, #00f2fe 100%);
}
.screenshot-card:nth-child(4) .screenshot-placeholder {
  background: linear-gradient(160deg, #43e97b 0%, #38f9d7 100%);
}

.screenshot-card:nth-child(n) .s-title,
.screenshot-card:nth-child(n) .s-desc {
  color: white;
}

.screenshot-card:nth-child(n) .s-desc {
  opacity: 0.85;
}

/* ===== 下载 CTA ===== */
.download-cta-section {
  text-align: center;
}

.download-box {
  max-width: 560px;
  margin: 0 auto;
  background: linear-gradient(135deg, var(--tf-primary) 0%, var(--tf-primary-dark) 100%);
  border-radius: var(--tf-radius-xl);
  padding: 56px 48px;
  color: white;
  box-shadow: 0 20px 60px rgba(74, 144, 226, 0.35);
  position: relative;
  overflow: hidden;
}

.download-box::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.15) 0%, transparent 70%);
  border-radius: 50%;
}

.download-box > * {
  position: relative;
  z-index: 1;
}

.download-icon {
  font-size: 3.5rem;
  margin-bottom: 20px;
}

.download-title {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.download-subtitle {
  font-size: 1rem;
  opacity: 0.9;
  margin-bottom: 8px;
}

.download-meta {
  font-size: 0.875rem;
  opacity: 0.8;
  margin-bottom: 32px;
}

.download-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

.download-box .btn-primary {
  background: white;
  color: var(--tf-primary);
  box-shadow: 0 4px 14px rgba(0, 0, 0, 0.15);
}

.download-box .btn-primary:hover {
  background: #f0f6ff;
  transform: translateY(-2px);
}

.download-box .btn-ghost {
  border-color: rgba(255, 255, 255, 0.4);
  color: white;
}

.download-box .btn-ghost:hover {
  border-color: white;
  background-color: rgba(255, 255, 255, 0.1);
  color: white;
}

/* ===== Footer ===== */
.app-footer {
  background-color: var(--tf-bg-secondary);
  border-top: 1px solid var(--tf-border-light);
  padding: 56px 0 24px;
  margin-top: auto;
}

.footer-inner {
  display: grid;
  grid-template-columns: 1.5fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 40px;
}

.footer-brand .logo {
  margin-bottom: 16px;
}

.footer-desc {
  color: var(--tf-text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
  margin-bottom: 20px;
  max-width: 320px;
}

.footer-social {
  display: flex;
  gap: 12px;
}

.social-link {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: var(--tf-bg-tertiary);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--tf-text-secondary);
  transition: var(--tf-transition);
}

.social-link:hover {
  background-color: var(--tf-primary);
  color: white;
  transform: translateY(-2px);
}

.footer-col-title {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--tf-text);
  margin-bottom: 20px;
}

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-links a {
  color: var(--tf-text-secondary);
  font-size: 0.9rem;
  transition: var(--tf-transition);
}

.footer-links a:hover {
  color: var(--tf-primary);
}

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--tf-border-light);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}

.footer-copy {
  font-size: 0.85rem;
  color: var(--tf-text-tertiary);
}

.footer-legal {
  display: flex;
  gap: 20px;
  font-size: 0.85rem;
}

.footer-legal a {
  color: var(--tf-text-tertiary);
}

.footer-legal a:hover {
  color: var(--tf-primary);
}

/* ===== 页面标题区 ===== */
.page-hero {
  padding: 64px 0 48px;
  background:
    radial-gradient(ellipse at top center, rgba(74, 144, 226, 0.1) 0%, transparent 60%),
    var(--tf-bg);
  text-align: center;
}

.page-hero-title {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--tf-text);
  margin-bottom: 16px;
  letter-spacing: -0.02em;
}

.page-hero-subtitle {
  font-size: 1.1rem;
  color: var(--tf-text-secondary);
  max-width: 640px;
  margin: 0 auto;
}

/* ===== 更新日志卡片 ===== */
.changelog-list {
  max-width: 800px;
  margin: 0 auto;
}

.changelog-item {
  background-color: var(--tf-bg-card);
  border-radius: var(--tf-radius-lg);
  padding: 32px;
  margin-bottom: 24px;
  border: 1px solid var(--tf-border-light);
  transition: var(--tf-transition);
  position: relative;
}

.changelog-item:hover {
  box-shadow: var(--tf-shadow-sm);
  border-color: var(--tf-border);
}

.changelog-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  border-radius: 4px 0 0 4px;
  background: linear-gradient(180deg, var(--tf-primary), var(--tf-secondary));
}

.changelog-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  margin-bottom: 20px;
  flex-wrap: wrap;
  gap: 12px;
}

.changelog-version {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
}

.version-tag {
  font-size: 1.25rem;
  font-weight: 800;
  color: var(--tf-text);
}

.version-type {
  padding: 4px 12px;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.version-type.major {
  background: rgba(255, 107, 107, 0.15);
  color: var(--tf-secondary);
}

.version-type.minor {
  background: rgba(74, 144, 226, 0.15);
  color: var(--tf-primary);
}

.version-type.patch {
  background: rgba(34, 197, 94, 0.15);
  color: #22C55E;
}

.changelog-meta {
  display: flex;
  align-items: center;
  gap: 16px;
  font-size: 0.9rem;
  color: var(--tf-text-tertiary);
  flex-wrap: wrap;
}

.changelog-meta .btn-sm {
  padding: 6px 14px;
  font-size: 0.85rem;
  border-radius: var(--tf-radius-sm);
}

.changelog-changes {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.change-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 10px 14px;
  background-color: var(--tf-bg-secondary);
  border-radius: var(--tf-radius-sm);
  font-size: 0.95rem;
  line-height: 1.5;
}

.change-tag {
  flex-shrink: 0;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.change-tag.feat {
  background: rgba(74, 144, 226, 0.15);
  color: var(--tf-primary);
}

.change-tag.fix {
  background: rgba(255, 107, 107, 0.15);
  color: var(--tf-secondary);
}

.change-tag.perf {
  background: rgba(34, 197, 94, 0.15);
  color: #22C55E;
}

.change-tag.refactor {
  background: rgba(168, 85, 247, 0.15);
  color: #A855F7;
}

.change-tag.docs {
  background: rgba(251, 146, 60, 0.15);
  color: #FB923C;
}

.change-text {
  color: var(--tf-text);
  flex: 1;
}

/* ===== FAQ 折叠面板 ===== */
.faq-container {
  max-width: 800px;
  margin: 0 auto;
}

.faq-category {
  margin-bottom: 40px;
}

.faq-category-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--tf-text);
  margin-bottom: 16px;
  padding-left: 12px;
  border-left: 4px solid var(--tf-primary);
}

.faq-item {
  background-color: var(--tf-bg-card);
  border: 1px solid var(--tf-border-light);
  border-radius: var(--tf-radius);
  margin-bottom: 12px;
  overflow: hidden;
  transition: var(--tf-transition);
}

.faq-item.active {
  border-color: var(--tf-primary);
  box-shadow: var(--tf-shadow-sm);
}

.faq-question {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  cursor: pointer;
  user-select: none;
  transition: var(--tf-transition);
}

.faq-question:hover {
  background-color: var(--tf-bg-secondary);
}

.faq-q-text {
  font-weight: 600;
  color: var(--tf-text);
  font-size: 1rem;
  flex: 1;
  padding-right: 16px;
}

.faq-icon {
  width: 24px;
  height: 24px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--tf-text-tertiary);
  transition: transform 0.3s ease;
}

.faq-item.active .faq-icon {
  transform: rotate(180deg);
  color: var(--tf-primary);
}

.faq-icon svg {
  width: 18px;
  height: 18px;
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
}

.faq-item.active .faq-answer {
  max-height: 600px;
}

.faq-answer-inner {
  padding: 0 24px 20px;
  color: var(--tf-text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
}

/* ===== 下载卡片 ===== */
.download-cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 900px;
  margin: 0 auto 48px;
}

.download-card {
  background-color: var(--tf-bg-card);
  border-radius: var(--tf-radius-lg);
  padding: 36px;
  border: 2px solid var(--tf-border-light);
  transition: var(--tf-transition);
  position: relative;
}

.download-card.recommended {
  border-color: var(--tf-primary);
  box-shadow: 0 0 0 4px rgba(74, 144, 226, 0.1);
}

.download-card.recommended::before {
  content: '推荐';
  position: absolute;
  top: -12px;
  right: 24px;
  padding: 4px 14px;
  background: linear-gradient(135deg, var(--tf-primary), var(--tf-secondary));
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  border-radius: 999px;
  letter-spacing: 0.05em;
}

.download-card-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 24px;
}

.download-card-icon {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.75rem;
  background: linear-gradient(135deg, rgba(74, 144, 226, 0.12) 0%, rgba(255, 107, 107, 0.1) 100%);
}

.download-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--tf-text);
}

.download-card-subtitle {
  font-size: 0.85rem;
  color: var(--tf-text-tertiary);
}

.download-info {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 24px;
}

.info-item {
  padding: 12px 16px;
  background-color: var(--tf-bg-secondary);
  border-radius: var(--tf-radius-sm);
}

.info-label {
  font-size: 0.75rem;
  color: var(--tf-text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}

.info-value {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--tf-text);
}

/* ===== About 页面 ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
  max-width: 1000px;
  margin: 0 auto;
}

.about-text h3 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--tf-text);
  margin-bottom: 16px;
}

.about-text p {
  color: var(--tf-text-secondary);
  line-height: 1.85;
  margin-bottom: 16px;
  font-size: 1rem;
}

.about-visual {
  aspect-ratio: 1;
  border-radius: var(--tf-radius-xl);
  background: linear-gradient(135deg, var(--tf-primary) 0%, var(--tf-secondary) 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 8rem;
  box-shadow: var(--tf-shadow-lg);
  position: relative;
  overflow: hidden;
}

.about-visual::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 30% 20%, rgba(255, 255, 255, 0.2) 0%, transparent 50%);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 40px;
  padding-top: 40px;
  border-top: 1px solid var(--tf-border-light);
}

.stat-item {
  text-align: center;
}

.stat-value {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--tf-primary);
  margin-bottom: 8px;
}

.stat-label {
  font-size: 0.9rem;
  color: var(--tf-text-secondary);
}

.contact-info {
  max-width: 600px;
  margin: 40px auto 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  text-align: center;
}

.contact-item {
  padding: 20px;
  background-color: var(--tf-bg-card);
  border-radius: var(--tf-radius);
  border: 1px solid var(--tf-border-light);
  transition: var(--tf-transition);
}

.contact-item:hover {
  border-color: var(--tf-primary);
  transform: translateY(-4px);
}

.contact-icon {
  font-size: 1.75rem;
  margin-bottom: 10px;
}

.contact-label {
  font-size: 0.8rem;
  color: var(--tf-text-tertiary);
  margin-bottom: 4px;
}

.contact-value {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--tf-text);
  word-break: break-all;
}

/* ===== Privacy 页面 ===== */
.privacy-content,
.terms-content {
  max-width: 800px;
  margin: 0 auto;
  background-color: var(--tf-bg-card);
  border-radius: var(--tf-radius-lg);
  padding: 48px;
  border: 1px solid var(--tf-border-light);
}

.privacy-content h2 {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--tf-text);
  margin: 32px 0 12px;
}

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

.privacy-content h3 {
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--tf-text);
  margin: 24px 0 10px;
}

.privacy-content p {
  color: var(--tf-text-secondary);
  line-height: 1.85;
  margin-bottom: 14px;
  font-size: 0.95rem;
}

.privacy-content ul {
  margin: 12px 0 14px 24px;
  list-style: disc;
}

.privacy-content li {
  color: var(--tf-text-secondary);
  line-height: 1.8;
  font-size: 0.95rem;
  margin-bottom: 6px;
}

.privacy-content strong {
  color: var(--tf-text);
}

/* ===== 回到顶部 ===== */
.back-to-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--tf-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--tf-shadow);
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: var(--tf-transition);
  z-index: 900;
}

.back-to-top.visible {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  transform: translateY(-4px);
  box-shadow: var(--tf-shadow-lg);
}

.back-to-top svg {
  width: 20px;
  height: 20px;
}

/* ===== 截图灯箱 ===== */
.lightbox {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.85);
  z-index: 2000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px;
  opacity: 0;
  visibility: hidden;
  transition: var(--tf-transition);
}

.lightbox.open {
  opacity: 1;
  visibility: visible;
}

.lightbox-content {
  max-width: 90vw;
  max-height: 90vh;
  background-color: var(--tf-bg-card);
  border-radius: var(--tf-radius-lg);
  overflow: hidden;
  transform: scale(0.95);
  transition: transform 0.3s ease;
  position: relative;
}

.lightbox.open .lightbox-content {
  transform: scale(1);
}

.lightbox-close {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background-color: rgba(0, 0, 0, 0.5);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  transition: var(--tf-transition);
}

.lightbox-close:hover {
  background-color: rgba(0, 0, 0, 0.7);
}

.lightbox-close svg {
  width: 22px;
  height: 22px;
}

.lightbox-image {
  width: 100%;
  height: 100%;
  min-width: 300px;
  min-height: 400px;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ===== 响应式 ===== */
@media (max-width: 1279px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .screenshot-gallery {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero-title {
    font-size: 2.75rem;
  }
}

@media (max-width: 1023px) {
  .hero-inner {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero-content {
    order: 2;
  }

  .hero-visual {
    order: 1;
  }

  .hero-phone {
    width: 240px;
    height: 480px;
  }

  .hero-subtitle {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-actions,
  .hero-features {
    justify-content: center;
  }

  .footer-inner {
    grid-template-columns: 1fr 1fr;
    gap: 32px;
  }

  .about-grid {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .about-visual {
    max-width: 360px;
    margin: 0 auto;
    font-size: 6rem;
  }
}

@media (max-width: 767px) {
  .page-section {
    padding: 48px 0;
  }

  .section-header {
    margin-bottom: 36px;
  }

  .section-title {
    font-size: 1.75rem;
  }

  .container {
    padding: 0 16px;
  }

  .nav-menu,
  .header-actions .btn {
    display: none;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .mobile-nav {
    display: block;
  }

  .hero {
    padding: 60px 0 48px;
  }

  .hero-title {
    font-size: 2rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .btn-lg {
    padding: 14px 24px;
    font-size: 1rem;
  }

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

  .feature-card {
    padding: 24px 20px;
  }

  .screenshot-gallery {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }

  .download-box {
    padding: 36px 24px;
  }

  .download-title {
    font-size: 1.5rem;
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-bottom {
    flex-direction: column;
    text-align: center;
  }

  .page-hero {
    padding: 40px 0 32px;
  }

  .page-hero-title {
    font-size: 1.875rem;
  }

  .changelog-item {
    padding: 24px 20px 20px;
  }

  .changelog-item::before {
    width: 3px;
  }

  .download-cards {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .download-card {
    padding: 24px;
  }

  .faq-question {
    padding: 16px 18px;
  }

  .faq-answer-inner {
    padding: 0 18px 16px;
  }

  .stats-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
  }

  .stat-value {
    font-size: 1.5rem;
  }

  .contact-info {
    grid-template-columns: 1fr;
  }

  .privacy-content {
    padding: 24px 20px;
  }

  .privacy-content h2 {
    font-size: 1.15rem;
  }

  .back-to-top {
    bottom: 20px;
    right: 20px;
    width: 44px;
    height: 44px;
  }

  .change-item {
    padding: 10px 12px;
    font-size: 0.9rem;
    flex-direction: column;
    align-items: flex-start;
  }
}

@media (max-width: 480px) {
  .hero-title {
    font-size: 1.75rem;
  }

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

  .hero-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .hero-actions .btn {
    width: 100%;
  }

  .download-actions {
    flex-direction: column;
    align-items: stretch;
  }

  .download-actions .btn {
    width: 100%;
  }
}