/* ===== 微聊助手官网 · 公共样式 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
  color: #1f2937;
  background: #ffffff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
button, .btn { cursor: pointer; font-family: inherit; }

:root {
  --primary: #1a73e8;
  --primary-dark: #0d47a1;
  --primary-light: #e8f0fe;
  --accent: #13ce66;
  --text: #1f2937;
  --text-muted: #6b7280;
  --bg: #ffffff;
  --bg-soft: #f8fafc;
  --border: #e5e7eb;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.12);
  --radius: 10px;
  --radius-lg: 16px;
  --maxw: 1180px;
}

/* ===== 导航 ===== */
.nav {
  position: sticky; top: 0; z-index: 100;
  height: 64px; background: rgba(255,255,255,0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-inner {
  max-width: var(--maxw); margin: 0 auto; height: 100%;
  display: flex; align-items: center; padding: 0 24px;
}
.nav-logo {
  font-size: 20px; font-weight: 700; color: var(--primary);
  display: flex; align-items: center; gap: 8px;
}
.nav-logo .dot {
  width: 28px; height: 28px; border-radius: 8px;
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 16px; font-weight: 700;
}
.nav-menu { display: flex; gap: 32px; margin-left: 48px; font-size: 15px; color: var(--text); }
.nav-menu a:hover { color: var(--primary); }
.nav-menu a.active { color: var(--primary); font-weight: 600; }
.nav-actions { margin-left: auto; display: flex; gap: 12px; align-items: center; }
.btn-login { color: var(--text); padding: 6px 14px; border-radius: 6px; font-size: 14px; }
.btn-login:hover { background: var(--bg-soft); }
.btn-primary {
  background: var(--primary); color: #fff; padding: 8px 20px;
  border-radius: 6px; font-size: 14px; font-weight: 500; border: none;
  transition: all .2s;
}
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-ghost {
  background: transparent; color: var(--primary); padding: 8px 20px;
  border-radius: 6px; font-size: 14px; font-weight: 500;
  border: 1px solid var(--primary);
}
.btn-ghost:hover { background: var(--primary-light); }

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

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, #f0f6ff 0%, #ffffff 60%, #e8f0fe 100%);
  padding: 80px 0 100px; overflow: hidden;
}
.hero-inner { display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center; }
.hero-tag {
  display: inline-block; padding: 6px 16px; border-radius: 20px;
  background: var(--primary-light); color: var(--primary); font-size: 13px; font-weight: 500;
  margin-bottom: 24px;
}
.hero h1 {
  font-size: 48px; font-weight: 700; line-height: 1.2; color: var(--text);
  margin-bottom: 20px;
}
.hero h1 .gradient {
  background: linear-gradient(135deg, var(--primary) 0%, #0066cc 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
}
.hero-desc { font-size: 17px; color: var(--text-muted); margin-bottom: 32px; line-height: 1.7; }
.hero-actions { display: flex; gap: 16px; margin-bottom: 32px; }
.hero-stats { display: flex; gap: 40px; }
.hero-stats .stat b { display: block; font-size: 28px; color: var(--primary); font-weight: 700; }
.hero-stats .stat span { font-size: 13px; color: var(--text-muted); }
.hero-visual {
  position: relative; background: #fff; border-radius: var(--radius-lg);
  padding: 24px; box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
}
.hero-visual::before {
  content: ''; position: absolute; inset: -4px; border-radius: 20px;
  background: linear-gradient(135deg, var(--primary), transparent 50%, transparent 50%, var(--accent));
  z-index: -1; opacity: 0.15; filter: blur(20px);
}
.chat-window { background: #f5f7fa; border-radius: 12px; overflow: hidden; }
.chat-header {
  height: 42px; background: #fff; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; padding: 0 12px; gap: 6px;
}
.chat-dot { width: 10px; height: 10px; border-radius: 50%; }
.chat-dot.r { background: #ff5f57; } .chat-dot.y { background: #febc2e; } .chat-dot.g { background: #28c840; }
.chat-title { margin-left: 12px; font-size: 13px; color: var(--text-muted); }
.chat-body { padding: 16px; font-size: 14px; }
.msg { margin-bottom: 16px; display: flex; }
.msg .bubble { max-width: 75%; padding: 10px 14px; border-radius: 12px; line-height: 1.5; }
.msg.me { justify-content: flex-end; }
.msg.me .bubble { background: var(--primary); color: #fff; border-bottom-right-radius: 4px; }
.msg.ai .bubble { background: #fff; border: 1px solid var(--border); border-bottom-left-radius: 4px; }
.msg-time { font-size: 11px; color: var(--text-muted); margin: 4px 0 0; }

/* ===== Section ===== */
.section { padding: 80px 0; }
.section-alt { background: var(--bg-soft); }
.section-head { text-align: center; margin-bottom: 56px; }
.section-tag {
  display: inline-block; padding: 4px 14px; border-radius: 16px;
  background: var(--primary-light); color: var(--primary);
  font-size: 12px; font-weight: 500; margin-bottom: 12px;
}
.section h2 { font-size: 36px; font-weight: 700; margin-bottom: 12px; }
.section .sub { font-size: 16px; color: var(--text-muted); max-width: 600px; margin: 0 auto; }

/* ===== Features Grid ===== */
.features {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.feature-card {
  background: #fff; padding: 32px 28px; border-radius: var(--radius);
  border: 1px solid var(--border); transition: all .25s;
}
.feature-card:hover {
  border-color: var(--primary); box-shadow: var(--shadow-md); transform: translateY(-4px);
}
.feature-icon {
  width: 48px; height: 48px; border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: 16px;
}
.feature-card:nth-child(1) .feature-icon { background: #e8f0fe; color: var(--primary); }
.feature-card:nth-child(2) .feature-icon { background: #e8f5e9; color: var(--accent); }
.feature-card:nth-child(3) .feature-icon { background: #fff3e0; color: #ff9800; }
.feature-card:nth-child(4) .feature-icon { background: #fce4ec; color: #e91e63; }
.feature-card:nth-child(5) .feature-icon { background: #f3e5f5; color: #9c27b0; }
.feature-card:nth-child(6) .feature-icon { background: #e0f7fa; color: #00acc1; }
.feature-card h3 { font-size: 18px; font-weight: 600; margin-bottom: 10px; }
.feature-card p { font-size: 14px; color: var(--text-muted); line-height: 1.7; }

/* ===== Pricing ===== */
.pricing-cards {
  display: grid; grid-template-columns: 1fr 1fr; gap: 32px; max-width: 820px; margin: 0 auto;
}
.price-card {
  background: #fff; border-radius: var(--radius-lg); padding: 40px 32px;
  border: 2px solid var(--border); transition: all .25s; position: relative;
}
.price-card.featured {
  border-color: var(--primary); box-shadow: var(--shadow-lg);
  transform: translateY(-8px);
}
.price-badge {
  position: absolute; top: -14px; left: 50%; transform: translateX(-50%);
  background: var(--primary); color: #fff; padding: 4px 16px;
  border-radius: 16px; font-size: 12px; font-weight: 600;
}
.price-card h3 { font-size: 22px; font-weight: 700; margin-bottom: 6px; }
.price-card .desc { font-size: 14px; color: var(--text-muted); margin-bottom: 24px; }
.price-amount { font-size: 48px; font-weight: 800; margin-bottom: 6px; }
.price-amount.free { color: var(--accent); }
.price-amount .unit { font-size: 15px; font-weight: 500; color: var(--text-muted); }
.price-trial {
  display: flex; align-items: center; gap: 8px;
  background: var(--primary-light); padding: 10px 14px; border-radius: 8px;
  color: var(--primary); font-size: 13px; font-weight: 500; margin-bottom: 24px;
}
.price-card.featured .price-trial { background: #fff3e0; color: #e65100; }
.price-features { list-style: none; margin-bottom: 28px; }
.price-features li {
  padding: 10px 0; font-size: 14px; color: var(--text);
  display: flex; align-items: flex-start; gap: 10px;
  border-bottom: 1px dashed var(--border);
}
.price-features li:last-child { border-bottom: none; }
.price-features li::before {
  content: "✓"; color: var(--accent); font-weight: 700; font-size: 15px;
  flex-shrink: 0;
}
.price-features li.na::before { content: "✕"; color: #d1d5db; }
.price-features li.na { color: #9ca3af; }
.price-btn {
  width: 100%; padding: 12px; border-radius: 8px;
  font-size: 15px; font-weight: 600; text-align: center;
  border: none; transition: all .2s;
}
.price-btn.default { background: var(--bg-soft); color: var(--text); border: 1px solid var(--border); }
.price-btn.default:hover { background: var(--border); }
.price-btn.primary { background: var(--primary); color: #fff; }
.price-btn.primary:hover { background: var(--primary-dark); box-shadow: var(--shadow-md); }

/* ===== CTA Banner ===== */
.cta-banner {
  background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
  padding: 64px 0; text-align: center; color: #fff;
}
.cta-banner h2 { font-size: 32px; font-weight: 700; margin-bottom: 12px; }
.cta-banner p { font-size: 16px; opacity: 0.9; margin-bottom: 28px; }
.cta-banner .btn-white {
  background: #fff; color: var(--primary); padding: 12px 36px;
  border-radius: 8px; font-size: 15px; font-weight: 600; border: none;
  transition: all .2s;
}
.cta-banner .btn-white:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,0.2); }

/* ===== FAQ ===== */
.faq-list { max-width: 780px; margin: 0 auto; }
.faq-item {
  border: 1px solid var(--border); border-radius: 10px;
  margin-bottom: 12px; background: #fff; overflow: hidden;
}
.faq-q {
  padding: 20px 24px; font-size: 15px; font-weight: 600;
  display: flex; justify-content: space-between; align-items: center; cursor: pointer;
  transition: background .15s;
}
.faq-q:hover { background: var(--bg-soft); }
.faq-q::after {
  content: '+'; font-size: 20px; font-weight: 400; color: var(--primary);
  transition: transform .2s;
}
.faq-item.open .faq-q::after { content: '−'; }
.faq-a {
  max-height: 0; overflow: hidden; transition: max-height .3s ease;
}
.faq-item.open .faq-a { max-height: 500px; }
.faq-a-inner { padding: 0 24px 20px; font-size: 14px; color: var(--text-muted); line-height: 1.8; }

/* ===== Help Article ===== */
.help-article { max-width: 760px; margin: 0 auto; font-size: 15px; }
.help-article h3 { font-size: 18px; font-weight: 600; margin: 32px 0 12px; color: var(--text); }
.help-article p { color: var(--text-muted); margin-bottom: 12px; line-height: 1.8; }
.help-article ul { margin: 12px 0 16px; padding-left: 20px; color: var(--text-muted); }
.help-article li { margin-bottom: 6px; }
.help-article code {
  background: var(--bg-soft); padding: 2px 8px; border-radius: 4px;
  font-size: 13px; font-family: Consolas, monospace; color: var(--primary-dark);
}
.help-article .tip {
  background: #fff9e6; border-left: 4px solid #ffc107; padding: 12px 16px;
  border-radius: 0 6px 6px 0; margin: 16px 0; font-size: 14px; color: #795548;
}

/* ===== Contact Cards ===== */
.contact-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; max-width: 900px; margin: 0 auto;
}
.contact-card {
  background: #fff; border: 1px solid var(--border); border-radius: var(--radius);
  padding: 32px 24px; text-align: center;
}
.contact-card .icon {
  width: 56px; height: 56px; border-radius: 14px;
  background: var(--primary-light); color: var(--primary);
  display: flex; align-items: center; justify-content: center;
  font-size: 26px; margin: 0 auto 16px;
}
.contact-card h4 { font-size: 16px; font-weight: 600; margin-bottom: 8px; }
.contact-card p { font-size: 14px; color: var(--text-muted); word-break: break-all; }

/* ===== Footer ===== */
.footer {
  background: #1f2937; color: #d1d5db; padding: 56px 0 28px; margin-top: 40px;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr 1fr; gap: 40px;
  max-width: var(--maxw); margin: 0 auto; padding: 0 24px;
}
.footer-brand .logo {
  font-size: 20px; font-weight: 700; color: #fff; margin-bottom: 12px;
  display: flex; align-items: center; gap: 8px;
}
.footer-brand .logo .dot {
  width: 28px; height: 28px; border-radius: 8px;
  background: linear-gradient(135deg, var(--primary), var(--primary-dark));
  display: flex; align-items: center; justify-content: center;
  color: #fff; font-size: 16px; font-weight: 700;
}
.footer-brand p { font-size: 14px; opacity: 0.7; line-height: 1.8; max-width: 280px; }
.footer-col h5 { font-size: 14px; font-weight: 600; color: #fff; margin-bottom: 16px; }
.footer-col ul { list-style: none; }
.footer-col li { padding: 6px 0; font-size: 13px; opacity: 0.75; cursor: pointer; }
.footer-col li:hover { opacity: 1; color: #fff; }
.footer-bottom {
  max-width: var(--maxw); margin: 40px auto 0; padding: 20px 24px 0;
  border-top: 1px solid rgba(255,255,255,0.1);
  font-size: 12px; opacity: 0.55; text-align: center;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero h1 { font-size: 36px; }
  .features { grid-template-columns: repeat(2, 1fr); }
  .pricing-cards { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .nav-menu { display: none; }
}
@media (max-width: 560px) {
  .features { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero-stats { gap: 24px; }
  .hero-actions { flex-direction: column; }
  .section h2 { font-size: 28px; }
}