/* Reset & Base */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  color: #1a1a2e;
  line-height: 1.6;
  background: #fff;
}
a { color: inherit; text-decoration: none; }
.container { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

/* Buttons */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
  border: none;
}
.btn-sm { padding: 8px 20px; font-size: 14px; }
.btn-lg { padding: 16px 36px; font-size: 17px; }
.btn-primary { background: #1a73e8; color: #fff; }
.btn-primary:hover { background: #1557b0; }
.btn-outline { border: 1px solid #ccc; color: #555; background: #fff; }
.btn-outline:hover { border-color: #999; color: #333; }

/* Nav */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 64px;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid #f0f0f0;
  z-index: 100;
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}
.logo {
  font-size: 18px;
  font-weight: 700;
}
.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  font-size: 14px;
  color: #555;
}
.nav-links a:hover { color: #1a73e8; }

/* Hero */
.hero {
  padding: 140px 0 80px;
  text-align: center;
  background: linear-gradient(180deg, #f8faff 0%, #fff 100%);
}
.hero h1 {
  font-size: 48px;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #1a73e8, #6c5ce7);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-desc {
  font-size: 18px;
  color: #666;
  max-width: 600px;
  margin: 0 auto 36px;
  line-height: 1.8;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 60px;
}

/* Preview Window */
.hero-preview { max-width: 640px; margin: 0 auto; }
.preview-window {
  border: 1px solid #e0e0e0;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.08);
}
.preview-bar {
  background: #f5f5f5;
  padding: 12px 16px;
  display: flex;
  gap: 8px;
}
.dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: #ddd;
}
.dot:first-child { background: #ff5f57; }
.dot:nth-child(2) { background: #ffbd2e; }
.dot:nth-child(3) { background: #28c840; }
.preview-content {
  padding: 24px;
  background: #fafafa;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.chat-bubble {
  padding: 12px 16px;
  border-radius: 12px;
  font-size: 14px;
  line-height: 1.6;
  max-width: 85%;
}
.chat-bubble.user {
  background: #1a73e8;
  color: #fff;
  align-self: flex-end;
  border-bottom-right-radius: 4px;
}
.chat-bubble.ai {
  background: #fff;
  border: 1px solid #e5e5e5;
  align-self: flex-start;
  border-bottom-left-radius: 4px;
}

/* Features */
.features {
  padding: 100px 0;
}
.features h2, .how-it-works h2, .cta h2 {
  text-align: center;
  font-size: 36px;
  font-weight: 700;
  margin-bottom: 12px;
}
.section-desc {
  text-align: center;
  color: #888;
  font-size: 16px;
  margin-bottom: 48px;
}
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}
.feature-card {
  padding: 32px 28px;
  border-radius: 12px;
  border: 1px solid #f0f0f0;
  transition: all 0.2s;
}
.feature-card:hover {
  border-color: #ddd;
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.05);
}
.feature-icon {
  font-size: 36px;
  margin-bottom: 16px;
}
.feature-card h3 {
  font-size: 20px;
  margin-bottom: 12px;
}
.feature-card p {
  font-size: 14px;
  color: #666;
  line-height: 1.7;
}

/* How it works */
.how-it-works {
  padding: 100px 0;
  background: #f8faff;
}
.steps {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
}
.step {
  text-align: center;
  flex: 1;
  max-width: 240px;
}
.step-num {
  width: 48px;
  height: 48px;
  line-height: 48px;
  border-radius: 50%;
  background: #1a73e8;
  color: #fff;
  font-size: 20px;
  font-weight: 700;
  margin: 0 auto 16px;
}
.step h3 {
  font-size: 18px;
  margin-bottom: 8px;
}
.step p {
  font-size: 14px;
  color: #666;
}
.step-arrow {
  font-size: 24px;
  color: #ccc;
  margin-top: -20px;
}

/* CTA */
.cta {
  padding: 80px 0;
}
.cta-inner {
  text-align: center;
  padding: 60px 40px;
  background: linear-gradient(135deg, #1a73e8, #6c5ce7);
  border-radius: 16px;
  color: #fff;
}
.cta-inner h2 {
  color: #fff;
  margin-bottom: 12px;
}
.cta-inner p {
  font-size: 16px;
  opacity: 0.9;
  margin-bottom: 28px;
}
.cta-inner .btn-primary {
  background: #fff;
  color: #1a73e8;
}
.cta-inner .btn-primary:hover {
  background: #f0f0f0;
}

/* Footer */
.footer {
  padding: 40px 0;
  border-top: 1px solid #f0f0f0;
}
.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.footer-left p {
  font-size: 13px;
  color: #999;
  margin-top: 4px;
}
.footer-right p {
  font-size: 13px;
  color: #999;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 { font-size: 32px; }
  .hero-desc { font-size: 16px; }
  .features-grid { grid-template-columns: 1fr; }
  .steps { flex-direction: column; }
  .step-arrow { transform: rotate(90deg); }
  .footer-inner { flex-direction: column; gap: 12px; text-align: center; }
}