:root {
  --bg: #f8fafc;
  --surface: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --line: #e2e8f0;
  --brand: #2563eb;
  --brand-dark: #1d4ed8;
  --accent: #0ea5e9;
  --radius: 14px;
  --shadow: 0 18px 50px -25px rgba(15, 23, 42, 0.35);
  --max: 1120px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", sans-serif;
  color: var(--text);
  background: radial-gradient(
      1200px 500px at 10% -10%,
      rgba(37, 99, 235, 0.12),
      transparent 55%
    ),
    radial-gradient(
      900px 400px at 100% 0%,
      rgba(14, 165, 233, 0.1),
      transparent 50%
    ),
    var(--bg);
  line-height: 1.65;
}

a {
  color: var(--brand);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
}

/* 避免带 .btn 的链接被全局 a 颜色干扰 */
a.btn {
  text-decoration: none;
}
a.btn:hover {
  text-decoration: none;
}

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(248, 250, 252, 0.95);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 12px;
  min-height: 64px;
  position: relative;
}

@media (min-width: 768px) {
  .header-inner {
    justify-content: space-between;
  }
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  min-width: 0;
  flex: 1;
}

.brand__link {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: inherit;
  flex-shrink: 0;
}
.brand__link:hover {
  text-decoration: none;
  opacity: 0.92;
}

.brand__logo {
  width: 124px;
  height: 40px;
  object-fit: contain;
  display: block;
  vertical-align: middle;
}

.brand__title {
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

@media (max-width: 640px) {
  .brand__title {
    font-size: 0.85rem;
  }
}

/* 移动端：汉堡按钮 */
.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  padding: 0;
  margin: 0;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: #fff;
  cursor: pointer;
  flex-shrink: 0;
}

.nav-toggle__bar {
  display: block;
  height: 2px;
  width: 20px;
  margin: 0 auto;
  background: var(--text);
  border-radius: 1px;
}

@media (min-width: 768px) {
  .nav-toggle {
    display: none;
  }
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 10px 18px;
  flex-wrap: nowrap;
  justify-content: flex-end;
}

/* 平板及以下：折叠为全宽下拉面板 */
@media (max-width: 767px) {
  body.nav-open {
    overflow: hidden;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    flex-wrap: nowrap;
    gap: 0;
    padding: 10px 16px 16px;
    margin: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--line);
    box-shadow: 0 16px 40px -28px rgba(15, 23, 42, 0.35);
  }

  .nav-links.is-open {
    display: flex;
  }

  .nav-links > a:not(.btn) {
    padding: 12px 4px;
    border-bottom: 1px solid var(--line);
    font-size: 1rem;
  }

  .nav-links .btn {
    margin-top: 8px;
    width: 100%;
    justify-content: center;
    box-sizing: border-box;
  }
}

.nav-links > a:not(.btn) {
  color: var(--muted);
  font-size: 0.95rem;
  text-decoration: none;
  font-weight: 500;
}
.nav-links > a:not(.btn):hover {
  color: var(--text);
  text-decoration: none;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 10px 18px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.15s ease, box-shadow 0.15s ease,
    background 0.15s ease;
}
.btn:hover {
  text-decoration: none;
}
.btn--primary {
  background: linear-gradient(135deg, var(--brand), var(--accent));
  color: #ffffff;
  box-shadow: 0 10px 28px -12px rgba(37, 99, 235, 0.85);
}
.btn--primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 14px 34px -12px rgba(37, 99, 235, 0.95);
  color: #ffffff;
}
.btn--ghost {
  background: #fff;
  border-color: var(--line);
  color: var(--text);
}
.btn--ghost:hover {
  border-color: #cbd5e1;
}

/* Hero */
.hero {
  padding: 56px 0 28px;
}

.hero__grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 40px;
  align-items: center;
}

@media (max-width: 900px) {
  .hero__grid {
    grid-template-columns: 1fr;
  }
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(37, 99, 235, 0.1);
  color: var(--brand-dark);
  font-size: 0.85rem;
  font-weight: 600;
}

.hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.35rem);
  line-height: 1.25;
  margin: 16px 0 12px;
  letter-spacing: 0.02em;
}

.hero__lead {
  font-size: 1.05rem;
  color: var(--muted);
  margin: 0 0 24px;
  max-width: 56ch;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.hero__card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}

.hero__card h3 {
  margin: 0 0 12px;
  font-size: 1.05rem;
}
.hero__card ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--muted);
  font-size: 0.95rem;
}
.hero__card li {
  margin: 6px 0;
}

/* Sections */
section {
  padding: 48px 0;
}

.section__head {
  text-align: center;
  max-width: 720px;
  margin: 0 auto 36px;
}

.section__head h2 {
  margin: 0 0 10px;
  font-size: 1.65rem;
  letter-spacing: 0.02em;
}

.section__head p {
  margin: 0;
  color: var(--muted);
}

/* 产品概述：与上下板块同宽对齐，略加大与首屏间距 */
#intro {
  padding-top: 72px;
}

#intro .section__head {
  max-width: 1000px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

@media (max-width: 780px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 22px 22px 18px;
  box-shadow: 0 10px 30px -28px rgba(15, 23, 42, 0.35);
}

.feature-card h3 {
  margin: 0 0 8px;
  font-size: 1.12rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.feature-card .tag {
  font-size: 0.72rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 6px;
  background: rgba(37, 99, 235, 0.12);
  color: var(--brand-dark);
  letter-spacing: 0.04em;
}

.feature-card p {
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 0.96rem;
}

.feature-card ul {
  margin: 0;
  padding-left: 1.1rem;
  color: var(--text);
  font-size: 0.92rem;
}

.feature-card li {
  margin: 6px 0;
}

/* Pricing */
.pricing {
  padding-bottom: 64px;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
  align-items: stretch;
}

@media (max-width: 960px) {
  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 440px;
    margin: 0 auto;
  }
}

.price-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px 22px;
  display: flex;
  flex-direction: column;
  position: relative;
  overflow: hidden;
}

.price-card--featured {
  border-color: rgba(37, 99, 235, 0.45);
  box-shadow: 0 22px 60px -34px rgba(37, 99, 235, 0.55);
}

.price-card__ribbon {
  position: absolute;
  top: 14px;
  right: -36px;
  background: linear-gradient(135deg, var(--brand), var(--accent));
  color: #fff;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 6px 40px;
  transform: rotate(45deg);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.35);
}

.price-card h3 {
  margin: 0 0 8px;
  font-size: 1.15rem;
}

.price-card .price {
  font-size: 1.85rem;
  font-weight: 800;
  letter-spacing: 0.02em;
  margin: 8px 0 4px;
}

.price-card .sub {
  color: var(--muted);
  font-size: 0.92rem;
  margin: 0 0 16px;
  min-height: 2.8em;
}

.price-card ul {
  margin: 0 0 18px;
  padding-left: 1.1rem;
  flex: 1;
  font-size: 0.92rem;
  color: var(--muted);
}

.price-card li {
  margin: 8px 0;
}

.site-footer {
  border-top: 1px solid var(--line);
  padding: 28px 0 40px;
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
}

.site-footer strong {
  color: var(--text);
}