/* ============== Reset & Base ============== */
*, *::before, *::after { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
  font-size: 14px;
  line-height: 1.6;
  color: #2D3748;
  background: #F4F7FB;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
a { color: inherit; text-decoration: none; }
button { font-family: inherit; cursor: pointer; border: 0; background: none; padding: 0; color: inherit; }
img, svg { display: block; max-width: 100%; }
h1, h2, h3, h4, p { margin: 0; }
ul { list-style: none; padding: 0; margin: 0; }

/* ============== Tokens ============== */
:root {
  --primary: #1E80FF;
  --primary-dark: #1A6FE0;
  --primary-light: #3D8AFF;
  --primary-bg: #E8F1FF;
  --primary-soft: #F4F8FF;
  --text-1: #1A202C;
  --text-2: #4A5568;
  --text-3: #718096;
  --border: #E2E8F0;
  --bg-soft: #F4F7FB;
  --bg-white: #FFFFFF;
  --shadow-sm: 0 2px 6px rgba(30,128,255,0.06);
  --shadow-md: 0 4px 16px rgba(30,128,255,0.08);
  --shadow-lg: 0 8px 32px rgba(30,128,255,0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --container: 1100px;
}

/* ============== Layout ============== */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}
.section {
  padding: 70px 0;
}
.section-title {
  font-size: 30px;
  font-weight: 700;
  color: var(--text-1);
  text-align: center;
  margin-bottom: 8px;
  letter-spacing: 0.5px;
}
.section-title-em {
  color: var(--primary);
  margin-left: 6px;
}
.section-sub {
  text-align: center;
  color: var(--text-3);
  font-size: 14px;
  margin-bottom: 40px;
}

/* ============== Topbar ============== */
.topbar {
  background: var(--primary);
  color: #fff;
  font-size: 12px;
  padding: 6px 0;
}
.topbar-inner {
  display: flex;
  align-items: center;
  gap: 6px;
}
.topbar-icon { display: inline-flex; }

/* ============== Header ============== */
.header {
  background: #fff;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 18px;
  color: var(--text-1);
}
.logo-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: var(--primary);
  color: #fff;
  border-radius: 8px;
  font-size: 16px;
  font-weight: 700;
}
.nav {
  display: flex;
  gap: 36px;
}
.nav-link {
  font-size: 15px;
  color: var(--text-2);
  position: relative;
  padding: 4px 0;
  transition: color .2s;
}
.nav-link:hover { color: var(--primary); }
.nav-link.active { color: var(--primary); font-weight: 600; }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  bottom: -22px;
  width: 22px;
  height: 3px;
  background: var(--primary);
  border-radius: 2px;
}
.header-cta { padding: 8px 18px; font-size: 14px; }
.btn-primary {
  background: var(--primary);
  color: #fff;
  border-radius: 20px;
  font-weight: 500;
  transition: background .2s, transform .2s;
}
.btn-primary:hover { background: var(--primary-dark); }

/* ============== Hero ============== */
.hero {
  position: relative;
  background: linear-gradient(135deg, #E8F1FF 0%, #F4F8FF 60%, #FFFFFF 100%);
  overflow: hidden;
  padding: 60px 0 80px;
}
.hero-bg {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 0;
}
.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: .35;
}
.hero-blob-1 {
  width: 420px; height: 420px;
  background: #B8D6FF;
  top: -120px; right: -100px;
}
.hero-blob-2 {
  width: 320px; height: 320px;
  background: #D5E6FF;
  bottom: -100px; left: 20%;
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(30,128,255,.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(30,128,255,.04) 1px, transparent 1px);
  background-size: 40px 40px;
  mask-image: linear-gradient(180deg, transparent 0%, #000 50%, transparent 100%);
  -webkit-mask-image: linear-gradient(180deg, transparent 0%, #000 50%, transparent 100%);
}
.hero-inner {
  position: relative;
  z-index: 1;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 40px;
}
.hero-text { flex: 1; max-width: 560px; }
.hero-eyebrow {
  display: inline-block;
  background: rgba(30,128,255,.1);
  color: var(--primary);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 12px;
  margin-bottom: 16px;
}
.hero-title {
  font-size: 36px;
  line-height: 1.4;
  font-weight: 700;
  color: var(--text-1);
  margin-bottom: 16px;
  letter-spacing: 1px;
}
.hero-sub {
  font-size: 15px;
  color: var(--text-3);
  margin-bottom: 32px;
}
.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}
.hero-action {
  display: flex;
  align-items: center;
  gap: 10px;
  background: #fff;
  padding: 12px 22px;
  border-radius: 10px;
  box-shadow: var(--shadow-md);
  transition: transform .2s, box-shadow .2s;
}
.hero-action:hover { transform: translateY(-2px); box-shadow: var(--shadow-lg); }
.hero-action-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 8px;
}
.hero-action-label { font-weight: 500; color: var(--text-1); font-size: 14px; }

.hero-figure {
  flex: 0 0 420px;
  width: 420px;
  height: 420px;
  filter: drop-shadow(0 20px 40px rgba(30,128,255,.15));
}

/* ============== Features ============== */
.section-features { background: #fff; }
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.feature-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: 28px 20px;
  text-align: center;
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--primary);
}
.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  background: var(--primary-soft);
  border-radius: 50%;
  margin-bottom: 12px;
}
.feature-title {
  font-size: 16px;
  font-weight: 600;
  color: var(--text-1);
  margin-bottom: 6px;
}
.feature-desc {
  font-size: 13px;
  color: var(--text-3);
}

/* ============== Compare ============== */
.section-compare { background: var(--bg-soft); }
.compare-table {
  background: #fff;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  max-width: 900px;
  margin: 0 auto;
}
.compare-row {
  display: grid;
  grid-template-columns: 120px 1fr 1.4fr;
  align-items: center;
  border-bottom: 1px solid var(--border);
}
.compare-row:last-child { border-bottom: 0; }
.compare-cell {
  padding: 18px 24px;
  font-size: 14px;
  color: var(--text-2);
}
.compare-head .compare-cell {
  background: #F4F8FF;
  font-weight: 600;
  color: var(--text-1);
}
.compare-head .compare-feature-cell {
  background: var(--primary);
  color: #fff;
}
.compare-label { font-weight: 600; color: var(--text-1); }
.compare-feature-cell {
  background: rgba(30,128,255,.06);
  color: var(--primary-dark);
  font-weight: 500;
}
.feature-pill {
  display: inline-block;
  background: var(--primary);
  color: #fff;
  padding: 4px 12px;
  border-radius: 14px;
  font-size: 12px;
  font-weight: 500;
}

/* ============== Courses ============== */
.section-courses { background: #fff; }
.course-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.course-card {
  background: #fff;
  border-radius: var(--radius-md);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  transition: transform .25s, box-shadow .25s;
  display: flex;
  flex-direction: column;
}
.course-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.course-cover {
  position: relative;
  height: 180px;
  overflow: hidden;
  background: #1A2B4C;
  display: flex;
  align-items: center;
  justify-content: center;
}
.course-cover-3 {
  background: #fff;
}
.course-tag {
  position: absolute;
  top: 12px;
  left: 12px;
  background: rgba(0,0,0,.4);
  color: #fff;
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 12px;
  backdrop-filter: blur(4px);
}
.course-body { padding: 20px; flex: 1; display: flex; flex-direction: column; }
.course-title { font-size: 16px; font-weight: 600; color: var(--text-1); margin-bottom: 6px; }
.course-desc { font-size: 13px; color: var(--text-3); margin-bottom: 14px; }
.course-price {
  color: #E53E3E;
  font-weight: 700;
  font-size: 24px;
  margin-top: auto;
}
.course-currency { font-size: 16px; }
.course-unit { font-size: 12px; color: var(--text-3); font-weight: 400; margin-left: 4px; }

.course-card-qr { align-items: center; padding-top: 30px; }
.course-card-qr .course-body { text-align: center; padding-top: 16px; }

/* ============== Reviews ============== */
.section-reviews { background: var(--bg-soft); }
.review-wrap {
  position: relative;
  display: flex;
  align-items: center;
  gap: 12px;
}
.review-track {
  flex: 1;
  overflow: hidden;
}
.review-slide {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  width: 100%;
}
.review-card {
  background: #fff;
  border-radius: var(--radius-md);
  padding: 24px;
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border);
  transition: transform .25s, box-shadow .25s;
}
.review-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); }
.review-head { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.review-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 600;
  font-size: 16px;
}
.review-avatar-1 { background: linear-gradient(135deg, #4FACFE, #00C9FE); }
.review-avatar-2 { background: linear-gradient(135deg, #FA709A, #FEE140); }
.review-avatar-3 { background: linear-gradient(135deg, #6A11CB, #2575FC); }
.review-name { font-weight: 600; color: var(--text-1); font-size: 14px; }
.review-stars { color: #FFB400; font-size: 12px; letter-spacing: 1px; }
.review-text {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.7;
  margin-bottom: 12px;
  min-height: 90px;
}
.review-tag {
  display: inline-block;
  background: var(--primary-soft);
  color: var(--primary);
  padding: 3px 10px;
  border-radius: 10px;
  font-size: 12px;
}
.review-arrow {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: #fff;
  color: var(--primary);
  box-shadow: var(--shadow-md);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  transition: background .2s, color .2s;
}
.review-arrow:hover { background: var(--primary); color: #fff; }
.review-dots {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 24px;
}
.review-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #C5D6EE;
  transition: background .2s, width .2s;
}
.review-dot.active { background: var(--primary); width: 24px; border-radius: 4px; }

/* ============== Flow ============== */
.section-flow { background: #fff; }
.flow {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}
.flow-step {
  flex: 0 0 200px;
  text-align: center;
  padding: 24px 16px;
  border-radius: var(--radius-md);
  background: linear-gradient(180deg, #F4F8FF 0%, #FFFFFF 100%);
  border: 1px solid #E0EAFC;
  position: relative;
}
.flow-num {
  position: absolute;
  top: -14px;
  left: 50%;
  transform: translateX(-50%);
  width: 28px;
  height: 28px;
  background: var(--primary);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 14px;
  box-shadow: 0 4px 12px rgba(30,128,255,.3);
}
.flow-icon {
  display: inline-flex;
  margin-bottom: 12px;
}
.flow-title { font-size: 16px; font-weight: 600; color: var(--text-1); margin-bottom: 4px; }
.flow-desc { font-size: 13px; color: var(--text-3); }
.flow-line { flex: 0 0 60px; height: 12px; opacity: .8; }

/* ============== FAQ ============== */
.section-faq { background: var(--bg-soft); }
.faq-list {
  max-width: 860px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.faq-item {
  background: #fff;
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  overflow: hidden;
  transition: box-shadow .2s, border-color .2s;
}
.faq-item.open { box-shadow: var(--shadow-md); border-color: var(--primary); }
.faq-q {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  text-align: left;
  padding: 18px 22px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text-1);
  transition: color .2s;
}
.faq-q:hover { color: var(--primary); }
.faq-icon {
  position: relative;
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  margin-left: 12px;
}
.faq-icon::before, .faq-icon::after {
  content: "";
  position: absolute;
  background: currentColor;
  transition: transform .3s;
  border-radius: 1px;
}
.faq-icon::before { top: 50%; left: 0; width: 18px; height: 2px; transform: translateY(-50%); }
.faq-icon::after { top: 0; left: 50%; width: 2px; height: 18px; transform: translateX(-50%); }
.faq-item.open .faq-icon { color: var(--primary); }
.faq-item.open .faq-icon::after { transform: translateX(-50%) rotate(90deg); }
.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height .3s ease;
}
.faq-item.open .faq-a { max-height: 200px; }
.faq-a p { padding: 0 22px 18px; font-size: 13px; color: var(--text-2); line-height: 1.7; }

/* ============== Footer ============== */
.footer {
  background: #fff;
  border-top: 1px solid var(--border);
  padding: 30px 0 36px;
  text-align: center;
}
.footer-inner { display: flex; flex-direction: column; align-items: center; gap: 8px; }
.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  font-size: 16px;
  color: var(--text-1);
  margin-bottom: 4px;
}
.footer-line { font-size: 12px; color: var(--text-3); }
.footer-icp { transition: color .2s; }
.footer-icp:hover { color: var(--primary); }
.footer-line-2 { color: var(--text-2); }

/* ============== Float Tools ============== */
.float-tools {
  position: fixed;
  right: 24px;
  bottom: 80px;
  z-index: 99;
  display: flex;
  flex-direction: column;
  gap: 12px;
}
.float-btn {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--primary);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: 0 6px 20px rgba(30,128,255,.35);
  transition: transform .2s, opacity .2s;
  position: relative;
}
.float-btn:hover { transform: translateY(-2px); }
.float-btn-tip::before {
  content: attr(data-tip);
  position: absolute;
  right: 56px;
  top: 50%;
  transform: translateY(-50%) translateX(8px);
  background: rgba(0,0,0,.78);
  color: #fff;
  font-size: 12px;
  padding: 5px 10px;
  border-radius: 4px;
  white-space: nowrap;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s, transform .2s;
}
.float-btn-tip:hover::before {
  opacity: 1;
  transform: translateY(-50%) translateX(0);
}
.float-btn-top { background: #5C9DFF; opacity: 0; pointer-events: none; transition: opacity .3s, transform .2s; }
.float-btn-top.show { opacity: 1; pointer-events: auto; }

/* ============== Reveal on scroll ============== */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .6s ease, transform .6s ease;
}
.reveal.in-view {
  opacity: 1;
  transform: translateY(0);
}

/* ============== Responsive ============== */
@media (max-width: 1100px) {
  :root { --container: 100%; }
  .feature-grid, .course-grid { grid-template-columns: repeat(2, 1fr); }
  .review-slide { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .nav { display: none; }
  .hero { padding: 40px 0 50px; }
  .hero-inner { flex-direction: column; text-align: center; }
  .hero-figure { width: 280px; height: 280px; }
  .hero-actions { justify-content: center; }
  .feature-grid, .course-grid, .review-slide { grid-template-columns: 1fr; }
  .flow { flex-wrap: wrap; }
  .flow-line { display: none; }
  .compare-row { grid-template-columns: 100px 1fr; }
  .compare-feature-cell { grid-column: 1 / -1; border-top: 1px dashed var(--border); }
  .section { padding: 50px 0; }
  .section-title { font-size: 24px; }
  .hero-title { font-size: 28px; }
}