:root {
  --blue-900: #0a3d7a;
  --blue-700: #1565c0;
  --blue-600: #1e7ae6;
  --blue-500: #2f8fff;
  --blue-100: #e8f3ff;
  --blue-50: #f3f8ff;
  --ink: #142033;
  --muted: #5a6b82;
  --line: #d7e4f5;
  --bg: #f7fafd;
  --white: #ffffff;
  --accent: #00a8a0;
  --radius: 14px;
  --shadow: 0 12px 36px rgba(21, 101, 192, 0.08);
  --max: 1120px;
  --font: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", sans-serif;
  --display: "Outfit", "Noto Sans SC", 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%, rgba(47, 143, 255, 0.18), transparent 60%),
    radial-gradient(900px 420px at 100% 0%, rgba(0, 168, 160, 0.12), transparent 55%),
    linear-gradient(180deg, #eef5ff 0%, var(--bg) 28%, #f9fbfe 100%);
  line-height: 1.75;
  font-size: 16px;
}

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

a {
  color: var(--blue-700);
  text-decoration: none;
}

a:hover {
  color: var(--blue-500);
  text-decoration: underline;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(14px);
  background: rgba(247, 250, 253, 0.86);
  border-bottom: 1px solid rgba(215, 228, 245, 0.9);
}

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

.brand {
  display: flex;
  align-items: center;
  gap: 0.7rem;
  color: var(--ink);
  text-decoration: none;
  font-family: var(--display);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand:hover {
  text-decoration: none;
  color: var(--blue-700);
}

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

.brand span {
  font-size: 1.15rem;
}

.nav {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem 1rem;
  align-items: center;
}

.nav a {
  color: var(--muted);
  font-size: 0.95rem;
  font-weight: 500;
  text-decoration: none;
  padding: 0.25rem 0;
}

.nav a:hover,
.nav a.active {
  color: var(--blue-700);
}

.menu-toggle {
  display: none;
  width: 42px;
  height: 42px;
  padding: 0;
  border: 1px solid var(--line);
  background: var(--white);
  color: var(--ink);
  border-radius: 10px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.menu-toggle .menu-icon {
  display: block;
  width: 20px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  position: relative;
  transition: background 0.2s ease;
}

.menu-toggle .menu-icon::before,
.menu-toggle .menu-icon::after {
  content: "";
  position: absolute;
  left: 0;
  width: 20px;
  height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: transform 0.2s ease, top 0.2s ease;
}

.menu-toggle .menu-icon::before {
  top: -6px;
}

.menu-toggle .menu-icon::after {
  top: 6px;
}

.menu-toggle[aria-expanded="true"] .menu-icon {
  background: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-icon::before {
  top: 0;
  transform: rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-icon::after {
  top: 0;
  transform: rotate(-45deg);
}

.hero {
  padding: 3.2rem 0 2.2rem;
}

.hero-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: 2rem;
  align-items: center;
}

.eyebrow {
  display: inline-block;
  color: var(--blue-700);
  background: var(--blue-100);
  border-radius: 999px;
  padding: 0.28rem 0.8rem;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 0.9rem;
}

.hero h1 {
  margin: 0 0 1rem;
  font-family: var(--display);
  font-size: clamp(1.85rem, 3.4vw, 2.7rem);
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.hero-lead {
  color: var(--muted);
  font-size: 1.05rem;
  margin: 0 0 1.4rem;
  max-width: 36rem;
}

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

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.72rem 1.2rem;
  border-radius: 999px;
  font-weight: 600;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

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

.btn-primary {
  background: linear-gradient(135deg, var(--blue-600), var(--blue-700));
  color: var(--white);
  box-shadow: 0 10px 24px rgba(30, 122, 230, 0.28);
}

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

.btn-ghost {
  background: var(--white);
  color: var(--blue-700);
  border-color: var(--line);
}

.btn-ghost:hover {
  color: var(--blue-700);
}

.hero-visual {
  position: relative;
}

.hero-visual img {
  width: 100%;
  border-radius: 22px;
  box-shadow: var(--shadow);
  border: 1px solid rgba(255, 255, 255, 0.7);
}

.hero-visual::after {
  content: "";
  position: absolute;
  inset: auto -8% -8% auto;
  width: 46%;
  height: 46%;
  background: radial-gradient(circle, rgba(0, 168, 160, 0.22), transparent 70%);
  z-index: -1;
  pointer-events: none;
}

.section {
  padding: 2.6rem 0;
}

.section-head {
  margin-bottom: 1.4rem;
}

.section-head h2 {
  margin: 0 0 0.55rem;
  font-size: clamp(1.4rem, 2.4vw, 1.9rem);
  line-height: 1.3;
}

.section-head p {
  margin: 0;
  color: var(--muted);
  max-width: 46rem;
}

.prose {
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.35rem 1.4rem;
  box-shadow: var(--shadow);
}

.prose h2,
.prose h3 {
  scroll-margin-top: 86px;
}

.prose h2 {
  margin: 1.8rem 0 0.8rem;
  font-size: 1.45rem;
  color: var(--blue-900);
}

.prose h2:first-child {
  margin-top: 0;
}

.prose h3 {
  margin: 1.35rem 0 0.55rem;
  font-size: 1.15rem;
}

.prose p {
  margin: 0 0 1rem;
  color: #243247;
}

.prose ul,
.prose ol {
  margin: 0 0 1rem;
  padding-left: 1.2rem;
}

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

.prose strong {
  color: var(--blue-900);
}

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

.feature-item {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.feature-item img {
  width: 100%;
  aspect-ratio: 9 / 16;
  object-fit: cover;
  object-position: top center;
  background: #edf3fb;
}

.feature-item .body {
  padding: 0.95rem 1rem 1.1rem;
}

.feature-item h3 {
  margin: 0 0 0.4rem;
  font-size: 1.05rem;
}

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

.shot-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 1.1rem 0 1.4rem;
}

.shot-row.three {
  grid-template-columns: repeat(3, 1fr);
}

.shot {
  margin: 0;
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 12px;
  overflow: hidden;
}

.shot img {
  width: 100%;
  aspect-ratio: 9 / 16;
  object-fit: cover;
  object-position: top center;
}

.shot figcaption {
  padding: 0.55rem 0.75rem 0.7rem;
  font-size: 0.88rem;
  color: var(--muted);
}

.toc {
  background: linear-gradient(180deg, #ffffff, #f4f9ff);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.15rem;
  margin-bottom: 1.4rem;
}

.toc h2 {
  margin: 0 0 0.6rem;
  font-size: 1.1rem;
}

.toc ol {
  margin: 0;
  padding-left: 1.15rem;
}

.toc li {
  margin-bottom: 0.35rem;
}

.page-hero {
  padding: 2.4rem 0 1rem;
}

.page-hero h1 {
  margin: 0 0 0.6rem;
  font-size: clamp(1.6rem, 3vw, 2.2rem);
}

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

.legal .prose {
  margin-bottom: 2rem;
}

.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-size: clamp(2rem, 5vw, 3.2rem);
  font-family: var(--display);
}

.error-page p {
  margin: 0 0 1.2rem;
  color: var(--muted);
}

.site-footer {
  margin-top: 2rem;
  border-top: 1px solid var(--line);
  background: rgba(255, 255, 255, 0.7);
  padding: 2rem 0 1.5rem;
}

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

.site-footer h3 {
  margin: 0 0 0.6rem;
  font-size: 1rem;
}

.site-footer p,
.site-footer a {
  color: var(--muted);
  font-size: 0.92rem;
}

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

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

.copyright {
  margin-top: 1.4rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.85rem;
}

.breadcrumb {
  font-size: 0.88rem;
  color: var(--muted);
  margin-bottom: 0.8rem;
}

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

.related {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.8rem;
  margin-top: 1.2rem;
}

.related a {
  display: block;
  background: var(--blue-50);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 0.85rem 1rem;
  text-decoration: none;
  color: var(--blue-900);
  font-weight: 600;
}

.related a:hover {
  background: var(--blue-100);
}

.related span {
  display: block;
  margin-top: 0.25rem;
  color: var(--muted);
  font-weight: 400;
  font-size: 0.88rem;
}

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

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

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

  .nav {
    display: none;
    position: absolute;
    top: calc(100% + 6px);
    right: 0;
    left: auto;
    width: min(220px, calc(100vw - 2rem));
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0.55rem;
    background: rgba(255, 255, 255, 0.98);
    border: 1px solid var(--line);
    border-radius: 12px;
    box-shadow: var(--shadow);
    z-index: 60;
  }

  .nav.open {
    display: flex;
  }

  .nav a {
    padding: 0.7rem 0.85rem;
    border-radius: 8px;
  }

  .nav a:hover,
  .nav a.active {
    background: var(--blue-50);
  }

  .nav-wrap {
    flex-wrap: nowrap;
  }

  .hero {
    padding-top: 1.8rem;
  }

  .feature-item img,
  .shot img {
    aspect-ratio: 3 / 4;
  }
}

@media (max-width: 560px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .prose {
    padding: 1rem;
  }
}