:root {
  --blue: #1a8fd8;
  --blue-dark: #0d6eaf;
  --blue-deep: #085a92;
  --sky: #e8f5fc;
  --ink: #1a2332;
  --muted: #5a6a7a;
  --line: #d5e4ef;
  --bg: #f4f9fc;
  --white: #ffffff;
  --radius: 12px;
  --shadow: 0 8px 28px rgba(13, 110, 175, 0.12);
  --max: 1120px;
  --font: "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

*,
*::before,
*::after {
  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%, #cfeaf8 0%, transparent 55%),
    radial-gradient(900px 420px at 100% 0%, #d7f0ff 0%, transparent 50%),
    linear-gradient(180deg, #eef7fc 0%, var(--bg) 180px);
  line-height: 1.75;
  font-size: 16px;
}

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

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

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

.container {
  width: min(100% - 32px, var(--max));
  margin-inline: auto;
}

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  text-decoration: none;
  font-weight: 700;
  font-size: 1.1rem;
}

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

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  align-items: center;
}

.nav a {
  color: var(--ink);
  font-size: 0.95rem;
  font-weight: 500;
  text-decoration: none;
}

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

.nav-toggle {
  display: none;
  border: 1px solid var(--line);
  background: var(--white);
  border-radius: 8px;
  padding: 8px 12px;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--ink);
}

/* Hero */
.hero {
  padding: 48px 0 28px;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 36px;
  align-items: center;
}

.hero-copy h1 {
  margin: 0 0 14px;
  font-size: clamp(1.7rem, 3.2vw, 2.45rem);
  line-height: 1.3;
  color: var(--blue-deep);
}

.hero-copy .lead {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 1.05rem;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 22px;
  border-radius: 999px;
  font-weight: 600;
  border: none;
  cursor: pointer;
  text-decoration: none;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn:hover {
  text-decoration: none;
  transform: translateY(-1px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--blue), var(--blue-dark));
  color: var(--white);
  box-shadow: 0 10px 24px rgba(26, 143, 216, 0.35);
}

.btn-primary:hover {
  color: var(--white);
}

.btn-ghost {
  background: var(--white);
  color: var(--blue-dark);
  border: 1px solid var(--line);
}

.hero-visual {
  position: relative;
}

.hero-visual img {
  width: 100%;
  max-width: 360px;
  margin-inline: auto;
  border-radius: 20px;
  box-shadow: var(--shadow);
  border: 4px solid var(--white);
}

.phone-frame {
  background: linear-gradient(160deg, #dff2fb, #ffffff);
  border-radius: 28px;
  padding: 18px;
  box-shadow: var(--shadow);
}

/* Sections */
.section {
  padding: 42px 0;
}

.section-alt {
  background: rgba(255, 255, 255, 0.65);
  border-block: 1px solid var(--line);
}

.section-head {
  margin-bottom: 24px;
}

.section-head h2 {
  margin: 0 0 8px;
  font-size: clamp(1.35rem, 2.4vw, 1.85rem);
  color: var(--blue-deep);
}

.section-head p {
  margin: 0;
  color: var(--muted);
  max-width: 720px;
}

.prose p {
  margin: 0 0 1em;
  color: #2a3644;
}

.prose h2,
.prose h3 {
  color: var(--blue-deep);
  scroll-margin-top: 80px;
}

.prose ul,
.prose ol {
  padding-left: 1.2em;
  color: #2a3644;
}

.prose li {
  margin-bottom: 0.45em;
}

/* Feature grids */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 4px 16px rgba(13, 110, 175, 0.06);
}

.feature-card img {
  width: 100%;
  aspect-ratio: 9 / 16;
  object-fit: cover;
  object-position: top;
  background: var(--sky);
}

.feature-card .body {
  padding: 14px 16px 18px;
}

.feature-card h3 {
  margin: 0 0 8px;
  font-size: 1.05rem;
  color: var(--ink);
}

.feature-card p {
  margin: 0;
  color: var(--muted);
  font-size: 0.94rem;
}

.shot-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 22px;
  align-items: start;
}

.shot-row img {
  border-radius: 16px;
  border: 3px solid var(--white);
  box-shadow: var(--shadow);
  width: 100%;
  max-width: 320px;
  margin-inline: auto;
}

.shot-copy h3 {
  margin-top: 0;
  color: var(--blue-deep);
}

.steps {
  counter-reset: step;
  display: grid;
  gap: 14px;
}

.step {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 14px;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 16px;
}

.step::before {
  counter-increment: step;
  content: counter(step);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--sky);
  color: var(--blue-dark);
  font-weight: 700;
  display: grid;
  place-items: center;
}

.toc {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin-bottom: 28px;
}

.toc h2 {
  margin: 0 0 10px;
  font-size: 1.1rem;
}

.toc ol {
  margin: 0;
  padding-left: 1.2em;
}

.toc a {
  font-weight: 500;
}

.faq details {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 12px 16px;
  margin-bottom: 10px;
}

.faq summary {
  cursor: pointer;
  font-weight: 600;
  color: var(--blue-deep);
}

.related {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.related a {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 14px;
  text-decoration: none;
  color: var(--ink);
  font-size: 0.92rem;
}

.related a:hover {
  border-color: var(--blue);
  color: var(--blue-dark);
}

/* Page hero small */
.page-hero {
  padding: 36px 0 10px;
}

.page-hero h1 {
  margin: 0 0 10px;
  color: var(--blue-deep);
  font-size: clamp(1.5rem, 2.8vw, 2rem);
}

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

.breadcrumb {
  font-size: 0.9rem;
  color: var(--muted);
  margin-bottom: 10px;
}

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

/* Error pages */
.error-wrap {
  min-height: 70vh;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 40px 16px;
}

.error-wrap h1 {
  font-size: 4rem;
  margin: 0;
  color: var(--blue);
}

.error-wrap p {
  color: var(--muted);
}

/* Footer */
.site-footer {
  margin-top: 40px;
  background: #0b3d5c;
  color: #d7e8f4;
  padding: 36px 0 22px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 24px;
  margin-bottom: 22px;
}

.site-footer h3 {
  margin: 0 0 12px;
  font-size: 1rem;
  color: #fff;
}

.site-footer a {
  color: #c5deef;
  text-decoration: none;
  display: inline-block;
  margin-bottom: 8px;
}

.site-footer a:hover {
  color: #fff;
  text-decoration: underline;
}

.footer-brand {
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.footer-brand img {
  width: 48px;
  height: 48px;
  border-radius: 10px;
}

.copyright {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding-top: 16px;
  font-size: 0.88rem;
  color: #9fbdd0;
  text-align: center;
}

/* Mobile */
@media (max-width: 900px) {
  .hero-grid,
  .shot-row,
  .footer-grid {
    grid-template-columns: 1fr;
  }

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

  .hero-visual img,
  .shot-row img {
    max-width: 280px;
  }
}

@media (max-width: 720px) {
  .nav-toggle {
    display: inline-flex;
  }

  .nav {
    display: none;
    width: 100%;
    flex-direction: column;
    align-items: flex-start;
    padding: 8px 0 12px;
  }

  .nav.open {
    display: flex;
  }

  .header-inner {
    flex-wrap: wrap;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }

  .hero {
    padding-top: 28px;
  }

  .section {
    padding: 32px 0;
  }

  .step {
    grid-template-columns: 40px 1fr;
  }

  .step::before {
    width: 40px;
    height: 40px;
  }
}