/* ========== Reset & Base ========== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: #0F172A;
  background: #F8FAFC;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { text-decoration: none; color: inherit; transition: color 0.2s; }
img { max-width: 100%; display: block; }
ul, ol { list-style: none; }

/* ========== Container ========== */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

/* ========== Navigation ========== */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(255,255,255,0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(0,0,0,0.06);
  height: 72px;
  transition: background 0.3s, box-shadow 0.3s;
}
.navbar .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 100%;
}
.nav-logo { display: flex; align-items: center; gap: 10px; font-weight: 700; font-size: 22px; color: #2563EB; }
.nav-logo svg { width: 36px; height: 36px; }
.nav-links { display: flex; align-items: center; gap: 32px; }
.nav-links a { font-size: 15px; color: #334155; font-weight: 500; transition: color 0.2s; }
.nav-links a:hover, .nav-links a.active { color: #2563EB; }
.nav-actions { display: flex; align-items: center; gap: 12px; }

/* ========== Buttons ========== */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 28px; border-radius: 8px; font-size: 16px; font-weight: 600;
  transition: all 0.25s ease; cursor: pointer; border: none; text-align: center;
}
.btn-primary {
  background: linear-gradient(135deg, #2563EB, #0EA5E9);
  color: #fff; box-shadow: 0 4px 14px rgba(37,99,235,0.3);
}
.btn-primary:hover { transform: translateY(-2px) scale(1.02); box-shadow: 0 6px 20px rgba(37,99,235,0.4); color: #fff; }
.btn-outline {
  background: transparent; color: #2563EB;
  border: 2px solid #2563EB;
}
.btn-outline:hover { background: #2563EB; color: #fff; }
.btn-sm { padding: 8px 20px; font-size: 14px; }
.btn-lg { padding: 16px 40px; font-size: 18px; }
.btn-amber { background: linear-gradient(135deg, #F59E0B, #F97316); color: #fff; box-shadow: 0 4px 14px rgba(245,158,11,0.3); }
.btn-amber:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(245,158,11,0.4); color: #fff; }

/* ========== Hero Section ========== */
.hero {
  padding: 160px 0 100px;
  background: linear-gradient(180deg, #EFF6FF 0%, #F8FAFC 100%);
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute; top: -200px; right: -200px;
  width: 600px; height: 600px;
  background: radial-gradient(circle, rgba(37,99,235,0.08) 0%, transparent 70%);
  border-radius: 50%;
}
.hero::after {
  content: '';
  position: absolute; bottom: -150px; left: -150px;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(14,165,233,0.06) 0%, transparent 70%);
  border-radius: 50%;
}
.hero-content { position: relative; z-index: 1; }
.hero h1 {
  font-size: 64px; font-weight: 800; line-height: 1.15;
  background: linear-gradient(135deg, #0F172A 0%, #2563EB 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; margin-bottom: 24px;
}
.hero .subtitle {
  font-size: 20px; color: #64748B; max-width: 640px; margin: 0 auto 32px;
  line-height: 1.7;
}
.hero-tags { display: flex; justify-content: center; flex-wrap: wrap; gap: 12px; margin-bottom: 40px; }
.hero-tag {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 20px; border-radius: 50px;
  background: #fff; color: #2563EB; font-size: 14px; font-weight: 500;
  border: 1px solid #DBEAFE;
  box-shadow: 0 2px 8px rgba(37,99,235,0.06);
}
.hero-cta { display: flex; justify-content: center; align-items: center; gap: 20px; margin-bottom: 32px; }
.hero-trust { font-size: 14px; color: #94A3B8; }
.hero-trust strong { color: #2563EB; }

/* ========== Device Mockup ========== */
.hero-devices {
  margin-top: 60px; position: relative; z-index: 1;
  display: flex; justify-content: center; align-items: flex-end; gap: 30px;
}
.device-phone {
  width: 220px; height: 440px;
  background: linear-gradient(145deg, #1E293B, #0F172A);
  border-radius: 32px; padding: 12px;
  box-shadow: 0 25px 60px rgba(0,0,0,0.15);
}
.device-phone-screen {
  width: 100%; height: 100%;
  background: linear-gradient(180deg, #2563EB, #0EA5E9);
  border-radius: 22px;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  color: #fff;
}
.device-phone-screen .connect-btn {
  width: 100px; height: 100px; border-radius: 50%;
  background: rgba(255,255,255,0.2); border: 3px solid rgba(255,255,255,0.5);
  display: flex; align-items: center; justify-content: center;
  font-size: 14px; font-weight: 600; margin-bottom: 16px;
}
.device-phone-screen .status { font-size: 16px; font-weight: 600; }
.device-phone-screen .node { font-size: 12px; opacity: 0.8; margin-top: 4px; }

/* ========== Section Common ========== */
.section { padding: 100px 0; }
.section-alt { background: #fff; }
.section-title {
  text-align: center; margin-bottom: 60px;
}
.section-title h2 {
  font-size: 40px; font-weight: 700; color: #0F172A; margin-bottom: 16px;
}
.section-title p {
  font-size: 18px; color: #64748B; max-width: 600px; margin: 0 auto;
}

/* ========== Features Grid ========== */
.features-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
}
.feature-card {
  background: #fff; border-radius: 16px; padding: 36px 28px;
  border: 1px solid #E2E8F0;
  transition: all 0.3s ease;
  text-align: center;
}
.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 12px 40px rgba(37,99,235,0.1);
  border-color: #BFDBFE;
}
.feature-icon {
  width: 64px; height: 64px; margin: 0 auto 20px;
  background: linear-gradient(135deg, #EFF6FF, #DBEAFE);
  border-radius: 16px;
  display: flex; align-items: center; justify-content: center;
}
.feature-icon svg { width: 32px; height: 32px; color: #2563EB; }
.feature-card h3 { font-size: 20px; font-weight: 600; margin-bottom: 12px; color: #0F172A; }
.feature-card p { font-size: 15px; color: #64748B; line-height: 1.7; }

/* ========== How It Works ========== */
.steps-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 40px;
  position: relative;
}
.steps-grid::before {
  content: '';
  position: absolute; top: 50px; left: 20%; right: 20%;
  height: 2px; background: linear-gradient(90deg, #DBEAFE, #2563EB, #DBEAFE);
}
.step-item { text-align: center; position: relative; z-index: 1; }
.step-number {
  width: 80px; height: 80px; margin: 0 auto 24px;
  background: linear-gradient(135deg, #2563EB, #0EA5E9);
  border-radius: 50%; color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 28px; font-weight: 700;
  box-shadow: 0 8px 24px rgba(37,99,235,0.3);
}
.step-item h3 { font-size: 20px; font-weight: 600; margin-bottom: 10px; }
.step-item p { font-size: 15px; color: #64748B; }

/* ========== Pricing ========== */
.pricing-grid {
  display: grid; grid-template-columns: repeat(2, 1fr); gap: 32px;
  max-width: 800px; margin: 0 auto;
}
.pricing-card {
  background: #fff; border-radius: 16px; padding: 40px 32px;
  border: 2px solid #E2E8F0; text-align: center;
  transition: all 0.3s ease; position: relative;
}
.pricing-card:hover { border-color: #BFDBFE; box-shadow: 0 12px 40px rgba(37,99,235,0.08); }
.pricing-card.featured {
  border-color: #2563EB;
  box-shadow: 0 12px 40px rgba(37,99,235,0.15);
}
.pricing-badge {
  position: absolute; top: -14px; left: 50%; transform: translateX(-50%);
  background: linear-gradient(135deg, #F59E0B, #F97316);
  color: #fff; padding: 4px 20px; border-radius: 50px;
  font-size: 13px; font-weight: 600;
}
.pricing-card h3 { font-size: 24px; font-weight: 700; margin-bottom: 8px; }
.pricing-card .price { font-size: 48px; font-weight: 800; color: #2563EB; margin: 16px 0; }
.pricing-card .price span { font-size: 16px; color: #64748B; font-weight: 400; }
.pricing-card .price-original { font-size: 16px; color: #94A3B8; text-decoration: line-through; }
.pricing-features { margin: 24px 0; text-align: left; }
.pricing-features li {
  padding: 8px 0; font-size: 15px; color: #334155;
  display: flex; align-items: center; gap: 10px;
}
.pricing-features li::before {
  content: ''; display: inline-block;
  width: 20px; height: 20px; flex-shrink: 0;
  background: #DCFCE7; border-radius: 50%;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20' fill='%2316A34A'%3E%3Cpath d='M16.707 5.293a1 1 0 010 1.414l-8 8a1 1 0 01-1.414 0l-4-4a1 1 0 011.414-1.414L8 12.586l7.293-7.293a1 1 0 011.414 0z'/%3E%3C/svg%3E");
  background-size: 14px; background-repeat: no-repeat; background-position: center;
}

/* Pricing Plans Tabs */
.pricing-tabs { display: flex; justify-content: center; gap: 12px; margin-bottom: 48px; flex-wrap: wrap; }
.pricing-tab {
  padding: 10px 24px; border-radius: 50px; font-size: 15px; font-weight: 500;
  background: #fff; color: #64748B; border: 1px solid #E2E8F0;
  transition: all 0.2s;
}
.pricing-tab:hover, .pricing-tab.active { background: #2563EB; color: #fff; border-color: #2563EB; }

/* Plans Grid */
.plans-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px;
  max-width: 1000px; margin: 0 auto;
}
.plan-card {
  background: #fff; border-radius: 12px; padding: 28px 20px;
  border: 1px solid #E2E8F0; text-align: center;
  transition: all 0.3s;
}
.plan-card:hover { border-color: #BFDBFE; transform: translateY(-4px); box-shadow: 0 8px 24px rgba(37,99,235,0.08); }
.plan-card.recommended { border-color: #2563EB; position: relative; }
.plan-card.recommended::before {
  content: '推荐';
  position: absolute; top: -10px; right: 16px;
  background: #F59E0B; color: #fff; padding: 2px 12px; border-radius: 50px;
  font-size: 12px; font-weight: 600;
}
.plan-duration { font-size: 16px; font-weight: 600; color: #0F172A; margin-bottom: 8px; }
.plan-price { font-size: 32px; font-weight: 800; color: #2563EB; margin: 12px 0; }
.plan-price small { font-size: 14px; color: #64748B; font-weight: 400; }
.plan-original { font-size: 14px; color: #94A3B8; text-decoration: line-through; }
.plan-save { display: inline-block; background: #FEF3C7; color: #D97706; padding: 2px 10px; border-radius: 50px; font-size: 12px; font-weight: 600; margin: 8px 0; }

/* ========== Stats / Trust ========== */
.stats-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px;
}
.stat-item { text-align: center; }
.stat-number { font-size: 48px; font-weight: 800; color: #2563EB; margin-bottom: 8px; }
.stat-label { font-size: 16px; color: #64748B; }

/* ========== Testimonials ========== */
.testimonials-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px;
}
.testimonial-card {
  background: #fff; border-radius: 16px; padding: 32px;
  border: 1px solid #E2E8F0;
}
.testimonial-stars { color: #F59E0B; font-size: 18px; margin-bottom: 16px; letter-spacing: 2px; }
.testimonial-text { font-size: 15px; color: #334155; line-height: 1.7; margin-bottom: 20px; }
.testimonial-author { display: flex; align-items: center; gap: 12px; }
.testimonial-avatar {
  width: 44px; height: 44px; border-radius: 50%;
  background: linear-gradient(135deg, #DBEAFE, #BFDBFE);
  display: flex; align-items: center; justify-content: center;
  font-size: 18px; font-weight: 600; color: #2563EB;
}
.testimonial-name { font-size: 15px; font-weight: 600; }
.testimonial-role { font-size: 13px; color: #94A3B8; }

/* ========== FAQ ========== */
.faq-list { max-width: 800px; margin: 0 auto; }
.faq-item {
  background: #fff; border-radius: 12px; margin-bottom: 16px;
  border: 1px solid #E2E8F0; overflow: hidden;
}
.faq-question {
  padding: 20px 24px; font-size: 17px; font-weight: 600;
  display: flex; align-items: center; justify-content: space-between;
  cursor: default;
}
.faq-question::after { content: '+'; font-size: 24px; color: #2563EB; font-weight: 300; }
.faq-answer {
  padding: 0 24px 20px;
  font-size: 15px; color: #64748B; line-height: 1.8;
}
.faq-answer ol { padding-left: 20px; list-style: decimal; }
.faq-answer ol li { margin-bottom: 8px; }

/* Help Page FAQ Steps */
.faq-step-list { max-width: 800px; margin: 0 auto; }
.faq-step-item {
  background: #fff; border-radius: 16px; margin-bottom: 24px;
  border: 1px solid #E2E8F0; padding: 32px;
  transition: all 0.3s;
}
.faq-step-item:hover { box-shadow: 0 8px 24px rgba(37,99,235,0.06); }
.faq-step-item h3 {
  font-size: 20px; font-weight: 600; color: #0F172A; margin-bottom: 16px;
  display: flex; align-items: flex-start; gap: 12px;
}
.faq-step-item h3 .faq-num {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 32px; height: 32px; border-radius: 8px;
  background: linear-gradient(135deg, #2563EB, #0EA5E9);
  color: #fff; font-size: 14px; font-weight: 700; flex-shrink: 0;
}
.faq-step-item .faq-steps { padding-left: 0; list-style: none; counter-reset: step; }
.faq-step-item .faq-steps li {
  counter-increment: step;
  padding: 10px 0 10px 44px; position: relative;
  font-size: 15px; color: #475569; line-height: 1.7;
  border-left: 2px solid #E2E8F0; margin-left: 15px;
}
.faq-step-item .faq-steps li::before {
  content: counter(step);
  position: absolute; left: -15px; top: 10px;
  width: 28px; height: 28px; border-radius: 50%;
  background: #EFF6FF; color: #2563EB;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; font-weight: 600; border: 2px solid #BFDBFE;
}
.faq-step-item .faq-steps li:last-child { border-left-color: transparent; }

/* ========== CTA Section ========== */
.cta-section {
  padding: 80px 0;
  background: linear-gradient(135deg, #2563EB, #0EA5E9);
  text-align: center; color: #fff;
}
.cta-section h2 { font-size: 36px; font-weight: 700; margin-bottom: 16px; }
.cta-section p { font-size: 18px; opacity: 0.9; margin-bottom: 32px; }
.cta-section .btn-primary {
  background: #fff; color: #2563EB;
  box-shadow: 0 4px 14px rgba(0,0,0,0.15);
}
.cta-section .btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(0,0,0,0.2); }

/* ========== Footer ========== */
.footer {
  background: #0F172A; color: #CBD5E1; padding: 60px 0 30px;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 40px;
  margin-bottom: 40px;
}
.footer-brand p { font-size: 14px; line-height: 1.7; margin-top: 12px; color: #94A3B8; }
.footer-col h4 { font-size: 16px; font-weight: 600; color: #fff; margin-bottom: 16px; }
.footer-col a { display: block; font-size: 14px; color: #94A3B8; padding: 4px 0; transition: color 0.2s; }
.footer-col a:hover { color: #fff; }
.footer-bottom {
  border-top: 1px solid #1E293B; padding-top: 24px;
  display: flex; justify-content: space-between; align-items: center;
  font-size: 13px; color: #64748B;
}
.footer-warning {
  background: rgba(245,158,11,0.1); border: 1px solid rgba(245,158,11,0.3);
  border-radius: 8px; padding: 12px 16px; margin-bottom: 24px;
  font-size: 13px; color: #F59E0B; text-align: center;
}

/* ========== Page Header (Inner Pages) ========== */
.page-header {
  padding: 140px 0 60px;
  background: linear-gradient(180deg, #EFF6FF 0%, #F8FAFC 100%);
  text-align: center;
}
.page-header h1 { font-size: 48px; font-weight: 700; color: #0F172A; margin-bottom: 16px; }
.page-header p { font-size: 18px; color: #64748B; max-width: 600px; margin: 0 auto; }

/* ========== Content Page ========== */
.content-page { padding: 60px 0 100px; }
.content-block { max-width: 800px; margin: 0 auto; }
.content-block h2 { font-size: 28px; font-weight: 600; color: #0F172A; margin: 40px 0 16px; }
.content-block h3 { font-size: 22px; font-weight: 600; color: #0F172A; margin: 32px 0 12px; }
.content-block p { font-size: 16px; color: #475569; line-height: 1.8; margin-bottom: 16px; }
.content-block ul { padding-left: 24px; margin-bottom: 16px; }
.content-block ul li { font-size: 16px; color: #475569; line-height: 1.8; margin-bottom: 8px; list-style: disc; }

/* ========== About Page ========== */
.about-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 40px; margin: 40px 0; }
.about-card {
  background: #fff; border-radius: 16px; padding: 32px;
  border: 1px solid #E2E8F0;
}
.about-card h3 { font-size: 20px; font-weight: 600; margin-bottom: 12px; color: #0F172A; }
.about-card p { font-size: 15px; color: #64748B; line-height: 1.7; }

/* ========== Platform Icons ========== */
.platforms-grid {
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px;
  max-width: 600px; margin: 40px auto;
}
.platform-item {
  text-align: center; padding: 24px;
  background: #fff; border-radius: 12px; border: 1px solid #E2E8F0;
  transition: all 0.3s;
}
.platform-item:hover { transform: translateY(-4px); box-shadow: 0 8px 24px rgba(37,99,235,0.08); }
.platform-item svg { width: 40px; height: 40px; margin: 0 auto 12px; color: #2563EB; }
.platform-item span { font-size: 14px; font-weight: 500; color: #334155; }

/* ========== Mobile Menu ========== */
.mobile-menu-btn { display: none; background: none; border: none; cursor: pointer; padding: 8px; }
.mobile-menu-btn svg { width: 28px; height: 28px; color: #334155; }

/* ========== Responsive ========== */
@media (max-width: 1024px) {
  .features-grid { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 24px; }
  .testimonials-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .plans-grid { grid-template-columns: repeat(2, 1fr); }
  .hero h1 { font-size: 48px; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .mobile-menu-btn { display: block; }
  .nav-actions .btn-outline { display: none; }
  .hero { padding: 120px 0 60px; }
  .hero h1 { font-size: 36px; }
  .hero .subtitle { font-size: 16px; }
  .hero-cta { flex-direction: column; gap: 12px; }
  .hero-devices { display: none; }
  .section { padding: 60px 0; }
  .section-title h2 { font-size: 28px; }
  .features-grid { grid-template-columns: 1fr; }
  .steps-grid { grid-template-columns: 1fr; gap: 32px; }
  .steps-grid::before { display: none; }
  .pricing-grid { grid-template-columns: 1fr; }
  .plans-grid { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stat-number { font-size: 36px; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 12px; text-align: center; }
  .page-header h1 { font-size: 32px; }
  .about-grid { grid-template-columns: 1fr; }
  .platforms-grid { grid-template-columns: repeat(2, 1fr); }
}