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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #333;
  line-height: 1.7;
  background: #f8f9fa;
}

.container { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* Hero */
.hero {
  background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
  color: #fff;
  text-align: center;
  padding: 80px 0 60px;
}

.hero h1 {
  font-size: 48px;
  font-weight: 700;
  margin-bottom: 10px;
  letter-spacing: 4px;
}

.hero .subtitle {
  font-size: 20px;
  color: #e94560;
  margin-bottom: 12px;
  font-weight: 500;
}

.hero .desc {
  font-size: 16px;
  color: #b0b8c8;
  margin-bottom: 30px;
}

.hero-features {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 40px;
}

.hero-features span {
  background: rgba(255,255,255,0.1);
  backdrop-filter: blur(10px);
  padding: 8px 20px;
  border-radius: 20px;
  font-size: 14px;
  border: 1px solid rgba(255,255,255,0.15);
}

.hero-cta p { color: #b0b8c8; margin-bottom: 15px; }

.qrcode-placeholder {
  display: inline-block;
  padding: 10px;
  background: #fff;
  border-radius: 12px;
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
  margin-bottom: 10px;
}

.mini-tip { font-size: 13px; color: #777; margin-top: 8px; }

/* Features */
.features {
  padding: 80px 0;
  background: #fff;
}

.features h2, .topics h2, .about h2 {
  text-align: center;
  font-size: 32px;
  margin-bottom: 50px;
  color: #1a1a2e;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 30px;
}

.feature-card {
  padding: 35px 25px;
  background: #f8f9fa;
  border-radius: 16px;
  text-align: center;
  transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 40px rgba(0,0,0,0.08);
}

.feature-icon { font-size: 40px; margin-bottom: 16px; }

.feature-card h3 {
  font-size: 18px;
  margin-bottom: 10px;
  color: #1a1a2e;
}

.feature-card p {
  font-size: 14px;
  color: #666;
}

/* Topics */
.topics {
  padding: 80px 0;
  background: #f8f9fa;
}

.tag-cloud {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 14px;
}

.tag {
  padding: 10px 24px;
  background: #fff;
  border-radius: 24px;
  font-size: 15px;
  color: #0f3460;
  border: 1px solid #e0e0e0;
  transition: all 0.2s;
}

.tag:hover {
  background: #0f3460;
  color: #fff;
  border-color: #0f3460;
}

/* About */
.about {
  padding: 80px 0;
  background: #fff;
}

.about p {
  max-width: 700px;
  margin: 0 auto 16px;
  text-align: center;
  color: #555;
  font-size: 15px;
}

/* Footer */
footer {
  background: #1a1a2e;
  color: #888;
  text-align: center;
  padding: 30px 0;
  font-size: 13px;
}

footer p { margin-bottom: 6px; }

footer a { color: #b0b8c8; text-decoration: none; }
footer a:hover { color: #e94560; }

footer .icp { margin-top: 12px; font-size: 12px; color: #666; }

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 32px; }
  .hero .subtitle { font-size: 16px; }
  .hero-features { gap: 10px; }
  .hero-features span { padding: 6px 14px; font-size: 12px; }
  .features h2, .topics h2, .about h2 { font-size: 24px; }
  .feature-grid { grid-template-columns: 1fr; }
}