:root {
  --accent: #10b981;
  --accent-dark: #059669;
  --accent-soft: #d1fae5;
  --ink: #0f172a;
  --ink-soft: #475569;
  --line: #e2e8f0;
  --bg: #ffffff;
  --bg-alt: #f8fafc;
  --radius: 14px;
  --shadow: 0 20px 45px -18px rgba(15, 23, 42, 0.25);
  --maxw: 1080px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", Roboto, Helvetica, Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

.container-narrow {
  max-width: 760px;
}

/* ---------- 顶部导航 ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 64px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--ink);
  font-weight: 700;
  font-size: 16px;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 15px;
}

.nav {
  display: flex;
  gap: 20px;
  margin-left: auto;
}

.nav a {
  color: var(--ink-soft);
  text-decoration: none;
  font-size: 14px;
  font-weight: 500;
}

.nav a:hover {
  color: var(--ink);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-buy {
  display: none;
}

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 40px;
  height: 40px;
  padding: 9px;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  cursor: pointer;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--ink);
  border-radius: 2px;
  transition: transform 0.2s ease, opacity 0.2s ease;
}

/* 菜单打开时汉堡变 × */
.site-header.menu-open .nav-toggle span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}
.site-header.menu-open .nav-toggle span:nth-child(2) {
  opacity: 0;
}
.site-header.menu-open .nav-toggle span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

.lang-toggle {
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink-soft);
  border-radius: 8px;
  padding: 7px 12px;
  font-size: 13px;
  cursor: pointer;
}

.lang-toggle:hover {
  border-color: var(--accent);
  color: var(--accent-dark);
}

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid transparent;
  border-radius: 10px;
  font-weight: 600;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.08s ease, background 0.15s ease, border-color 0.15s ease;
}

.btn:active {
  transform: translateY(1px);
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-dark);
}

.btn-ghost {
  background: transparent;
  color: var(--ink);
  border-color: var(--line);
}

.btn-ghost:hover {
  border-color: var(--ink-soft);
}

.btn-sm {
  padding: 8px 14px;
  font-size: 13px;
}

.btn-lg {
  padding: 14px 24px;
  font-size: 15px;
}

.btn-buy {
  width: 100%;
}

.btn:disabled {
  opacity: 0.6;
  cursor: default;
}

/* ---------- Hero ---------- */
.hero {
  background: radial-gradient(1200px 600px at 50% -20%, #134e4a 0%, #0f172a 55%);
  color: #e2e8f0;
  padding: 88px 0 72px;
  text-align: center;
}

.hero-badge {
  display: inline-block;
  background: rgba(16, 185, 129, 0.15);
  color: #6ee7b7;
  border: 1px solid rgba(16, 185, 129, 0.35);
  border-radius: 999px;
  padding: 6px 14px;
  font-size: 13px;
  font-weight: 500;
  margin-bottom: 22px;
}

.hero h1 {
  font-size: clamp(36px, 6vw, 60px);
  line-height: 1.08;
  margin: 0 0 18px;
  letter-spacing: -0.02em;
  color: #fff;
}

.hero-sub {
  font-size: 18px;
  color: #cbd5e1;
  max-width: 620px;
  margin: 0 auto 34px;
}

.hero-demo {
  max-width: 460px;
  margin: 0 auto 34px;
}

.demo-window {
  background: #0b1220;
  border: 1px solid #1e293b;
  border-radius: var(--radius);
  padding: 14px 16px;
  text-align: left;
  box-shadow: var(--shadow);
}

.demo-dots {
  display: flex;
  gap: 6px;
  margin-bottom: 12px;
}

.demo-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #334155;
}

.demo-box {
  display: flex;
  align-items: center;
  gap: 8px;
  background: #0f172a;
  border: 1px solid #1e293b;
  border-radius: 8px;
  padding: 10px 12px;
  font-size: 15px;
}

.demo-prompt {
  color: var(--accent);
}

.demo-query {
  color: #e2e8f0;
}

.demo-preview {
  color: #64748b;
  font-size: 13px;
  padding: 8px 4px 0;
}

.hero-cta {
  display: flex;
  gap: 14px;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-note {
  color: #94a3b8;
  font-size: 13px;
  margin-top: 22px;
}

/* ---------- 通用 section ---------- */
.section {
  padding: 88px 0;
}

/* 锚点跳转时给 sticky 头部留出空间 */
section[id] {
  scroll-margin-top: 76px;
}

.section-alt {
  background: var(--bg-alt);
}

.section-title {
  font-size: clamp(26px, 4vw, 36px);
  text-align: center;
  margin: 0 0 12px;
  letter-spacing: -0.01em;
}

.section-sub {
  text-align: center;
  color: var(--ink-soft);
  font-size: 17px;
  margin: 0 auto 48px;
  max-width: 560px;
}

/* ---------- 功能卡片 ---------- */
.grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 26px 24px;
}

.card-icon {
  font-size: 28px;
  margin-bottom: 14px;
}

.card h3 {
  font-size: 17px;
  margin: 0 0 8px;
}

.card p {
  color: var(--ink-soft);
  font-size: 14px;
  margin: 0;
}

/* 7 张卡片时，最后一张（多币种）在最后一行居中 */
.grid .card:nth-child(7) {
  grid-column: 2 / 3;
}

/* ---------- 步骤 ---------- */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  margin-top: 8px;
}

.step {
  text-align: center;
}

.step-num {
  width: 40px;
  height: 40px;
  margin: 0 auto 16px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent-dark);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step h3 {
  font-size: 16px;
  margin: 0 0 8px;
}

.step p {
  color: var(--ink-soft);
  font-size: 14px;
  margin: 0;
}

/* ---------- 定价 ---------- */
.pricing-card {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
  padding: 40px 36px;
  text-align: center;
  max-width: 420px;
  margin: 0 auto;
}

.price-line {
  display: flex;
  align-items: baseline;
  justify-content: center;
  gap: 10px;
  margin-bottom: 24px;
}

.price {
  font-size: 52px;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.price-term {
  color: var(--ink-soft);
  font-size: 15px;
}

.pricing-features {
  list-style: none;
  padding: 0;
  margin: 0 0 28px;
  text-align: left;
}

.pricing-features li {
  padding: 8px 0;
  color: var(--ink-soft);
  font-size: 15px;
  border-bottom: 1px solid var(--bg-alt);
}

.pricing-features li::before {
  content: "✓";
  color: var(--accent-dark);
  font-weight: 700;
  margin-right: 10px;
}

.pricing-note {
  min-height: 20px;
  font-size: 13px;
  color: var(--ink-soft);
  margin: 14px 0 0;
}

/* ---------- 下载 ---------- */
.download-row {
  display: flex;
  justify-content: center;
}

.download-note {
  text-align: center;
  color: var(--ink-soft);
  font-size: 13px;
  margin-top: 18px;
}

/* ---------- FAQ ---------- */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: #fff;
  overflow: hidden;
}

.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 18px 20px;
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
}

.faq-q::after {
  content: "+";
  font-size: 20px;
  color: var(--ink-soft);
  transition: transform 0.2s ease;
}

.faq-item.open .faq-q::after {
  transform: rotate(45deg);
}

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.25s ease;
  padding: 0 20px;
  color: var(--ink-soft);
  font-size: 14px;
}

.faq-item.open .faq-a {
  padding-bottom: 18px;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 28px 0;
  background: var(--bg-alt);
}

.footer-inner {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
  color: var(--ink-soft);
  font-size: 13px;
}

/* ---------- 响应式 ---------- */
@media (max-width: 860px) {
  /* 隐藏桌面端头部购买按钮，改用汉堡菜单里的入口 */
  .btn-header-buy {
    display: none;
  }

  .nav-toggle {
    display: inline-flex;
  }

  .nav {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    margin-left: 0;
    flex-direction: column;
    gap: 0;
    background: #fff;
    border-bottom: 1px solid var(--line);
    box-shadow: 0 24px 40px -20px rgba(15, 23, 42, 0.25);
    padding: 6px 24px 16px;
  }

  .site-header.menu-open .nav {
    display: flex;
  }

  .nav a {
    padding: 13px 0;
    font-size: 16px;
    border-bottom: 1px solid var(--bg-alt);
  }

  .nav a.nav-buy {
    display: flex;
    justify-content: center;
    margin-top: 14px;
    padding: 12px;
    border-radius: 10px;
    border-bottom: none;
    background: var(--accent);
    color: #fff;
    font-weight: 600;
  }

  .nav a.nav-buy:hover {
    color: #fff;
    background: var(--accent-dark);
  }

  .grid,
  .steps {
    grid-template-columns: 1fr;
  }

  /* 单列布局下取消第七张卡片居中占位 */
  .grid .card:nth-child(7) {
    grid-column: auto;
  }

  .hero {
    padding: 56px 0 48px;
  }
  .section {
    padding: 64px 0;
  }
  .footer-inner {
    flex-direction: column;
  }
}

@media (max-width: 480px) {
  .header-inner {
    height: 60px;
  }
  .brand-name {
    font-size: 15px;
  }
  .hero-sub {
    font-size: 16px;
  }
  .hero-cta {
    flex-direction: column;
    align-items: stretch;
  }
  .hero-cta .btn {
    width: 100%;
  }
  .pricing-card {
    padding: 30px 22px;
  }
  .price {
    font-size: 44px;
  }
  .section-title {
    font-size: 24px;
  }
  .section-sub {
    font-size: 15px;
  }
}