:root {
  --bg: #f8fafc;
  --bg-elevated: #f1f5f9;
  --bg-card: #ffffff;
  --border: rgba(15, 23, 42, 0.1);
  --text: #1e293b;
  --text-muted: #64748b;
  --accent: #2d5a9e;
  --accent-light: #3b6fc4;
  --accent-glow: rgba(45, 90, 158, 0.2);
  --gradient-start: #e8f0fb;
  --gradient-end: #dbeafe;
  --radius: 16px;
  --radius-sm: 10px;
  --font: "Segoe UI", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  --max-width: 1120px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

a:hover {
  color: #1d4ed8;
}

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

.container {
  width: min(100% - 2rem, var(--max-width));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(248, 250, 252, 0.9);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.85rem 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  color: var(--text);
  font-weight: 600;
  font-size: 1.1rem;
}

.brand img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.95rem;
}

.nav-links a:hover {
  color: var(--text);
}

.nav-links a.btn-primary,
a.btn-primary {
  color: #fff;
}

.nav-links a.btn-primary:hover,
a.btn-primary:hover {
  color: #fff;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.65rem 1.25rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  border: none;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.2s, background 0.2s;
}

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

.btn-primary {
  background: linear-gradient(135deg, var(--accent-light), var(--accent));
  color: #fff;
  box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:hover {
  color: #fff;
  box-shadow: 0 6px 28px var(--accent-glow);
}

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

.btn-outline:hover {
  background: rgba(45, 90, 158, 0.06);
  color: var(--accent);
  border-color: rgba(45, 90, 158, 0.25);
}

.btn-lg {
  padding: 0.85rem 1.75rem;
  font-size: 1rem;
  border-radius: 12px;
}

/* Hero */
.hero {
  position: relative;
  padding: 4.5rem 0 5rem;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(45, 90, 158, 0.1), transparent),
    radial-gradient(ellipse 50% 40% at 90% 50%, rgba(45, 90, 158, 0.06), transparent);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.hero-badge {
  display: inline-block;
  padding: 0.35rem 0.85rem;
  border-radius: 999px;
  background: rgba(45, 90, 158, 0.08);
  border: 1px solid rgba(45, 90, 158, 0.18);
  color: var(--accent);
  font-size: 0.85rem;
  font-weight: 500;
  margin-bottom: 1.25rem;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.2rem);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.02em;
  margin-bottom: 1rem;
}

.hero-desc {
  font-size: 1.125rem;
  color: var(--text-muted);
  max-width: 32rem;
  margin-bottom: 2rem;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin-bottom: 2rem;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.hero-meta span {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.hero-visual {
  display: flex;
  justify-content: center;
}

.phone-mock {
  width: 280px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 32px;
  padding: 10px;
  box-shadow:
    0 20px 48px rgba(15, 23, 42, 0.12),
    0 0 0 1px rgba(15, 23, 42, 0.06) inset;
}

.phone-screenshot {
  width: 100%;
  height: auto;
  border-radius: 22px;
  display: block;
}

/* Screenshots */
.screenshots {
  background: var(--bg-elevated);
  border-block: 1px solid var(--border);
}

.screenshots-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.screenshot-card {
  margin: 0;
}

.screenshot-frame {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 0.75rem;
  box-shadow: 0 4px 20px rgba(15, 23, 42, 0.06);
  overflow: hidden;
}

.screenshot-frame img {
  width: 100%;
  height: auto;
  border-radius: calc(var(--radius) - 4px);
  display: block;
}

.screenshot-card figcaption {
  padding: 1rem 0.25rem 0;
  text-align: center;
}

.screenshot-card figcaption strong {
  display: block;
  font-size: 1.05rem;
  margin-bottom: 0.25rem;
  color: var(--text);
}

.screenshot-card figcaption span {
  font-size: 0.88rem;
  color: var(--text-muted);
}

/* Sections */
section {
  padding: 5rem 0;
}

.section-header {
  text-align: center;
  max-width: 36rem;
  margin: 0 auto 3rem;
}

.section-header h2 {
  font-size: clamp(1.75rem, 3vw, 2.25rem);
  font-weight: 700;
  margin-bottom: 0.75rem;
  letter-spacing: -0.02em;
}

.section-header p {
  color: var(--text-muted);
  font-size: 1.05rem;
}

.features {
  background: var(--bg-elevated);
  border-block: 1px solid var(--border);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem 1.5rem;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.04);
  transition: border-color 0.2s, box-shadow 0.2s, transform 0.2s;
}

.feature-card:hover {
  border-color: rgba(45, 90, 158, 0.25);
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
  transform: translateY(-3px);
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: rgba(45, 90, 158, 0.1);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 1rem;
}

.feature-card h3 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.55;
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.about-content h2 {
  font-size: 2rem;
  margin-bottom: 1rem;
}

.about-content p {
  color: var(--text-muted);
  margin-bottom: 1rem;
}

.about-stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
}

.stat-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-align: center;
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.04);
}

.stat-card strong {
  display: block;
  font-size: 1.5rem;
  color: var(--accent);
  margin-bottom: 0.25rem;
}

.stat-card span {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.download {
  text-align: center;
  background: linear-gradient(180deg, var(--gradient-start), var(--gradient-end));
  border-top: 1px solid var(--border);
}

.download h2 {
  font-size: 2rem;
  margin-bottom: 0.75rem;
  color: var(--text);
}

.download p {
  color: var(--text-muted);
  margin-bottom: 2rem;
  max-width: 28rem;
  margin-inline: auto;
}

.play-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  background: #000;
  color: #fff;
  padding: 0.65rem 1.25rem;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  transition: background 0.2s, transform 0.15s;
}

.play-badge:hover {
  background: #1a1a1a;
  color: #fff;
  transform: translateY(-2px);
}

.play-badge svg {
  width: 28px;
  height: 28px;
}

.play-badge-text {
  text-align: left;
  line-height: 1.2;
}

.play-badge-text small {
  display: block;
  font-size: 0.65rem;
  opacity: 0.8;
}

.play-badge-text strong {
  font-size: 1rem;
}

/* Footer */
.site-footer {
  padding: 2.5rem 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  list-style: none;
}

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

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

/* Mobile nav toggle */
.menu-toggle {
  display: none;
  background: none;
  border: none;
  color: var(--text);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0.25rem;
}

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

  .hero-desc {
    margin-inline: auto;
  }

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

  .hero-meta {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .phone-mock {
    width: 240px;
  }

  .screenshots-grid {
    grid-template-columns: 1fr;
    max-width: 320px;
    margin-inline: auto;
  }

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

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

  .about-stats {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-elevated);
    border-bottom: 1px solid var(--border);
    padding: 1rem;
    gap: 0.75rem;
  }

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

  .site-header .container {
    position: relative;
  }

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

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