/* Douyin Media - Main Stylesheet */
:root {
  --bg-primary: #0d0d12;
  --bg-secondary: #16161f;
  --bg-card: #1e1e2a;
  --text-primary: #f0f0f5;
  --text-secondary: #a0a0b8;
  --accent-cyan: #00f2ea;
  --accent-magenta: #ff0050;
  --accent-red: #e63946;
  --border-color: #2a2a3a;
  --max-width: 1200px;
  --radius: 12px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.4);
}

*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.75;
  min-height: 100vh;
}

a {
  color: var(--accent-cyan);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--accent-magenta);
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* Header + sticky ad bar */
.site-top {
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header {
  position: relative;
  z-index: 2;
  background: rgba(13, 13, 18, 0.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  max-width: var(--max-width);
  margin: 0 auto;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo-link img {
  width: 42px;
  height: 42px;
  border-radius: 8px;
}

.logo-text {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  background: linear-gradient(90deg, var(--accent-cyan), var(--accent-magenta));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.main-nav {
  display: flex;
  gap: 28px;
  list-style: none;
}

.main-nav a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
}

.main-nav a:hover,
.main-nav a.active {
  color: var(--accent-cyan);
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
}

/* Hero */
.hero {
  padding: 60px 0 50px;
  background: linear-gradient(
    135deg,
    rgba(0, 242, 234, 0.06) 0%,
    rgba(255, 0, 80, 0.06) 100%
  );
  border-bottom: 1px solid var(--border-color);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
  align-items: center;
}

.hero h1 {
  font-size: 2.2rem;
  line-height: 1.3;
  margin-bottom: 16px;
}

.hero-desc {
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 28px;
}

.btn-group {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 28px;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
  color: #fff;
  box-shadow: 0 4px 20px rgba(255, 0, 80, 0.3);
}

.btn-secondary {
  background: var(--bg-card);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.hero-phone {
  max-width: 320px;
  margin: 0 auto;
  border-radius: 24px;
  overflow: hidden;
  box-shadow: var(--shadow), 0 0 40px rgba(0, 242, 234, 0.1);
  border: 2px solid var(--border-color);
}

/* Sections */
.section {
  padding: 56px 0;
}

.section-alt {
  background: var(--bg-secondary);
}

.section-title {
  font-size: 1.75rem;
  text-align: center;
  margin-bottom: 12px;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

/* Feature cards */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 28px;
  transition: border-color 0.2s, transform 0.2s;
}

.feature-card:hover {
  border-color: var(--accent-cyan);
  transform: translateY(-4px);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 14px;
}

.feature-card h3 {
  font-size: 1.1rem;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.92rem;
}

/* Screenshot gallery */
.gallery-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.gallery-item {
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border-color);
  transition: transform 0.2s;
}

.gallery-item:hover {
  transform: scale(1.02);
  border-color: var(--accent-magenta);
}

.gallery-item img {
  width: 100%;
  aspect-ratio: 9/16;
  object-fit: cover;
}

.gallery-caption {
  padding: 14px 16px;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.gallery-caption strong {
  color: var(--text-primary);
  display: block;
  margin-bottom: 4px;
}

/* Category tags */
.category-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
  margin-bottom: 32px;
}

.tag {
  display: inline-block;
  padding: 8px 18px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: 50px;
  font-size: 0.88rem;
  color: var(--text-secondary);
  transition: all 0.2s;
}

.tag:hover {
  border-color: var(--accent-red);
  color: var(--accent-red);
  background: rgba(230, 57, 70, 0.1);
}

/* Content article */
.article-content {
  max-width: 860px;
  margin: 0 auto;
}

.article-content h2 {
  font-size: 1.5rem;
  margin: 36px 0 16px;
  padding-left: 14px;
  border-left: 4px solid var(--accent-cyan);
}

.article-content h3 {
  font-size: 1.15rem;
  margin: 24px 0 12px;
  color: var(--accent-cyan);
}

.article-content p {
  margin-bottom: 16px;
  color: var(--text-secondary);
}

.article-content ul,
.article-content ol {
  margin: 12px 0 16px 24px;
  color: var(--text-secondary);
}

.article-content li {
  margin-bottom: 8px;
}

.article-content a {
  text-decoration: underline;
  text-underline-offset: 3px;
}

/* FAQ */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}

.faq-item {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  margin-bottom: 14px;
  overflow: hidden;
}

.faq-question {
  padding: 18px 22px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.faq-answer {
  padding: 0 22px 18px;
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Page header for subpages */
.page-header {
  padding: 48px 0 32px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  text-align: center;
}

.page-header h1 {
  font-size: 2rem;
  margin-bottom: 10px;
}

.page-header p {
  color: var(--text-secondary);
}

.page-content {
  padding: 48px 0 64px;
}

.page-content .article-content h2 {
  margin-top: 32px;
}

/* Error pages */
.error-page {
  min-height: 70vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px 20px;
}

.error-code {
  font-size: 6rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--accent-cyan), var(--accent-magenta));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 16px;
}

.error-page h1 {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.error-page p {
  color: var(--text-secondary);
  margin-bottom: 28px;
}

/* Footer */
.site-footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 48px 0 24px;
  margin-top: auto;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 36px;
}

.footer-brand img {
  width: 48px;
  margin-bottom: 14px;
}

.footer-brand p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  max-width: 320px;
}

.footer-links h4 {
  font-size: 0.95rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.footer-links ul {
  list-style: none;
}

.footer-links li {
  margin-bottom: 10px;
}

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

.footer-links a:hover {
  color: var(--accent-cyan);
}

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 20px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
}

/* Breadcrumb */
.breadcrumb {
  padding: 14px 0;
  font-size: 0.88rem;
  color: var(--text-secondary);
}

.breadcrumb a {
  color: var(--text-secondary);
}

.breadcrumb a:hover {
  color: var(--accent-cyan);
}

.breadcrumb span {
  margin: 0 8px;
}

/* Download CTA banner */
.cta-banner {
  background: linear-gradient(135deg, rgba(0, 242, 234, 0.12), rgba(255, 0, 80, 0.12));
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 40px;
  text-align: center;
  margin: 40px 0;
}

.cta-banner h2 {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.cta-banner p {
  color: var(--text-secondary);
  margin-bottom: 24px;
}

/* Responsive */
@media (max-width: 900px) {
  .hero-grid {
    grid-template-columns: 1fr;
    text-align: center;
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  .btn-group {
    justify-content: center;
  }

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

  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
}

@media (max-width: 640px) {
  .header-inner {
    position: relative;
  }

  .logo-link {
    order: 1;
    min-width: 0;
  }

  .nav-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    order: 2;
    margin-left: auto;
    padding: 8px;
    min-width: 44px;
    min-height: 44px;
    flex-shrink: 0;
  }

  nav {
    order: 3;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    z-index: 20;
  }

  .main-nav {
    display: none;
    position: static;
    background: var(--bg-secondary);
    flex-direction: column;
    padding: 16px 20px;
    gap: 16px;
    border-bottom: 1px solid var(--border-color);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.45);
  }

  .main-nav.open {
    display: flex;
  }

  .features-grid,
  .gallery-grid {
    grid-template-columns: 1fr;
  }

  .footer-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 40px 0 30px;
  }
}

/* Ad bar (below header, sticks with .site-top) */
.ad-bar-sticky {
  position: relative;
  z-index: 1;
  background: rgba(22, 22, 31, 0.97);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border-color);
  padding: 10px 12px;
}

#ads {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  flex-wrap: wrap;
  gap: 8px 12px;
  background: transparent;
  max-width: var(--max-width);
  margin: 0 auto;
}

#ads > div {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 70px;
  box-sizing: border-box;
}

#ads img {
  width: 65px;
  height: 65px;
  object-fit: cover;
  border-radius: 18px;
  box-shadow: 0 6px 18px rgba(0, 0, 0, 0.35);
  transition: transform 180ms ease, box-shadow 180ms ease;
  display: block;
  border: none;
  background: linear-gradient(135deg, #fff, #fff);
}

#ads a {
  display: inline-block;
  text-decoration: none;
  border-radius: 15px;
}

#ads img:hover {
  transform: translateY(-4px) scale(1.04);
  box-shadow: 0 10px 24px rgba(0, 242, 234, 0.25);
}

#ads figcaption,
#ads .caption {
  height: 15px;
  font-size: 11px;
  color: var(--text-secondary);
  text-align: center;
  max-width: 100px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-top: 4px;
}