:root {
  --blue: #1f8fd8;
  --blue-deep: #0d6eac;
  --blue-soft: #e8f5fd;
  --ink: #152033;
  --muted: #5a6a7e;
  --line: #d7e6f2;
  --bg: #f3f8fc;
  --white: #ffffff;
  --radius: 14px;
  --shadow: 0 12px 36px rgba(15, 78, 130, 0.1);
  --max: 1120px;
  --font: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: "ZCOOL XiaoWei", "Noto Serif SC", serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 500px at 10% -10%, #d9efff 0%, transparent 55%),
    radial-gradient(900px 400px at 100% 0%, #cfe9fb 0%, transparent 50%),
    linear-gradient(180deg, #f7fbfe 0%, var(--bg) 40%, #eef6fb 100%);
  line-height: 1.75;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--blue-deep);
  text-decoration: none;
}

a:hover {
  color: var(--blue);
}

.container {
  width: min(100% - 2rem, var(--max));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.88);
  border-bottom: 1px solid rgba(215, 230, 242, 0.9);
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 68px;
  gap: 1rem;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  font-weight: 700;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  object-fit: cover;
}

.brand span {
  font-size: 1.05rem;
  letter-spacing: 0.02em;
}

.nav {
  display: flex;
  align-items: center;
  gap: 0.35rem;
}

.nav a {
  color: var(--muted);
  padding: 0.45rem 0.75rem;
  border-radius: 999px;
  font-size: 0.95rem;
  transition: 0.2s ease;
}

.nav a:hover,
.nav a.active {
  color: var(--blue-deep);
  background: var(--blue-soft);
}

.menu-btn {
  display: none;
  border: 1px solid var(--line);
  background: var(--white);
  width: 42px;
  height: 42px;
  border-radius: 10px;
  cursor: pointer;
}

.menu-btn span {
  display: block;
  width: 18px;
  height: 2px;
  margin: 4px auto;
  background: var(--ink);
}

/* Hero */
.hero {
  position: relative;
  overflow: hidden;
  padding: 4.2rem 0 3.2rem;
  min-height: min(88vh, 760px);
  display: flex;
  align-items: center;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(700px 320px at 85% 20%, rgba(31, 143, 216, 0.28), transparent 70%),
    radial-gradient(520px 260px at 10% 80%, rgba(120, 196, 240, 0.22), transparent 65%),
    linear-gradient(115deg, rgba(243, 248, 252, 0.96) 0%, rgba(232, 245, 253, 0.9) 48%, rgba(196, 226, 246, 0.55) 100%);
  z-index: -1;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 2.2rem;
  align-items: center;
}

.hero-copy h1 {
  margin: 0 0 0.8rem;
  font-family: var(--display);
  font-size: clamp(2.1rem, 4.4vw, 3.4rem);
  line-height: 1.2;
  letter-spacing: 0.02em;
}

.hero-copy .lead {
  margin: 0 0 1.4rem;
  color: var(--muted);
  font-size: 1.08rem;
  max-width: 36em;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 46px;
  padding: 0.7rem 1.25rem;
  border-radius: 12px;
  font-weight: 600;
  border: 1px solid transparent;
  transition: 0.2s ease;
}

.btn-primary {
  background: linear-gradient(135deg, var(--blue), var(--blue-deep));
  color: #fff;
  box-shadow: 0 10px 24px rgba(13, 110, 172, 0.28);
}

.btn-primary:hover {
  color: #fff;
  transform: translateY(-1px);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.85);
  border-color: var(--line);
  color: var(--blue-deep);
}

.hero-visual {
  position: relative;
}

.hero-visual img {
  width: min(100%, 360px);
  margin-inline: auto;
  border-radius: 28px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, 0.7);
  animation: floaty 5.5s ease-in-out infinite;
}

@keyframes floaty {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-10px); }
}

@keyframes fadeup {
  from { opacity: 0; transform: translateY(18px); }
  to { opacity: 1; transform: translateY(0); }
}

.reveal {
  animation: fadeup 0.7s ease both;
}

/* Sections */
.section {
  padding: 3.4rem 0;
}

.section-head {
  margin-bottom: 1.6rem;
  max-width: 46rem;
}

.section-head h2 {
  margin: 0 0 0.55rem;
  font-family: var(--display);
  font-size: clamp(1.55rem, 2.8vw, 2.15rem);
  line-height: 1.25;
}

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

.prose {
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.4rem 1.5rem;
  box-shadow: 0 8px 24px rgba(15, 78, 130, 0.04);
}

.prose p {
  margin: 0 0 1rem;
}

.prose p:last-child {
  margin-bottom: 0;
}

.prose h3 {
  margin: 1.4rem 0 0.7rem;
  font-size: 1.2rem;
}

.prose ul,
.prose ol {
  margin: 0 0 1rem;
  padding-left: 1.2rem;
  color: var(--muted);
}

.prose li {
  margin: 0.35rem 0;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.1rem;
}

.feature {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 8px 22px rgba(15, 78, 130, 0.05);
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.feature:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow);
}

.feature img {
  width: 100%;
  aspect-ratio: 9 / 16;
  object-fit: cover;
  object-position: top;
  background: #eaf4fb;
}

.feature-body {
  padding: 1rem 1.05rem 1.15rem;
}

.feature-body h3 {
  margin: 0 0 0.45rem;
  font-size: 1.05rem;
}

.feature-body p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.split {
  display: grid;
  grid-template-columns: 0.95fr 1.05fr;
  gap: 1.4rem;
  align-items: center;
}

.split.reverse {
  grid-template-columns: 1.05fr 0.95fr;
}

.split-media img {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  box-shadow: var(--shadow);
  max-height: 620px;
  object-fit: cover;
  object-position: top;
}

.chip-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1rem 0 0;
}

.chip {
  display: inline-block;
  padding: 0.35rem 0.75rem;
  border-radius: 999px;
  background: var(--blue-soft);
  color: var(--blue-deep);
  font-size: 0.86rem;
}

.toc {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.75rem;
}

.toc a {
  display: block;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.9rem 1rem;
  color: var(--ink);
  transition: 0.2s ease;
}

.toc a:hover {
  border-color: #9ecced;
  background: var(--blue-soft);
  color: var(--blue-deep);
}

.toc strong {
  display: block;
  margin-bottom: 0.2rem;
}

.toc span {
  color: var(--muted);
  font-size: 0.88rem;
}

.faq details {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.9rem 1rem;
  margin-bottom: 0.7rem;
}

.faq summary {
  cursor: pointer;
  font-weight: 600;
}

.faq p {
  margin: 0.7rem 0 0;
  color: var(--muted);
}

.page-hero {
  padding: 2.6rem 0 1.2rem;
}

.page-hero h1 {
  margin: 0 0 0.6rem;
  font-family: var(--display);
  font-size: clamp(1.8rem, 3.4vw, 2.5rem);
}

.page-hero p {
  margin: 0;
  color: var(--muted);
  max-width: 42rem;
}

.legal .prose h2 {
  margin: 1.6rem 0 0.7rem;
  font-size: 1.25rem;
}

.breadcrumb {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.breadcrumb a {
  color: var(--muted);
}

.error-page {
  min-height: 70vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 3rem 1rem;
}

.error-page h1 {
  margin: 0 0 0.6rem;
  font-family: var(--display);
  font-size: clamp(2rem, 5vw, 3.2rem);
}

.error-page p {
  margin: 0 0 1.3rem;
  color: var(--muted);
}

.site-footer {
  margin-top: 2rem;
  padding: 2.4rem 0 2rem;
  background: linear-gradient(180deg, transparent, #e4f1fa);
  border-top: 1px solid var(--line);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 1.5rem;
}

.site-footer h3 {
  margin: 0 0 0.7rem;
  font-size: 1rem;
}

.site-footer p,
.site-footer a {
  color: var(--muted);
}

.site-footer ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.site-footer li {
  margin: 0.35rem 0;
}

.copyright {
  margin-top: 1.6rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.88rem;
}

.related {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 1rem;
}

.related a {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.4rem 0.85rem;
  color: var(--blue-deep);
  font-size: 0.9rem;
}

/* Mobile */
@media (max-width: 960px) {
  .hero-grid,
  .split,
  .split.reverse,
  .feature-grid,
  .toc,
  .footer-grid {
    grid-template-columns: 1fr;
  }

  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero {
    min-height: auto;
    padding: 2.4rem 0 2rem;
  }

  .hero::before {
    background:
      radial-gradient(520px 240px at 50% 0%, rgba(31, 143, 216, 0.24), transparent 70%),
      linear-gradient(180deg, rgba(243, 248, 252, 0.96) 0%, rgba(232, 245, 253, 0.88) 55%, rgba(196, 226, 246, 0.5) 100%);
  }

  .hero-visual img {
    max-width: 220px;
    margin-inline: auto;
    border-radius: 28px;
  }

  .menu-btn {
    display: inline-block;
  }

  .nav {
    display: none;
    position: absolute;
    left: 1rem;
    right: 1rem;
    top: 68px;
    flex-direction: column;
    align-items: stretch;
    background: #fff;
    border: 1px solid var(--line);
    border-radius: 14px;
    padding: 0.55rem;
    box-shadow: var(--shadow);
  }

  .nav.open {
    display: flex;
  }

  .nav a {
    padding: 0.75rem 0.9rem;
  }
}

@media (max-width: 640px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .feature img,
  .split-media img {
    aspect-ratio: 3 / 4;
    max-height: 520px;
  }

  .prose {
    padding: 1.1rem;
  }

  .section {
    padding: 2.4rem 0;
  }
}