:root {
  color-scheme: light dark;
  --blue: #1677ff;
  --blue-deep: #075fcc;
  --cyan: #30b8e2;
  --orange: #ff9f1c;
  --ink: #10243e;
  --muted: #5c6f86;
  --line: rgba(16, 76, 135, 0.12);
  --card: rgba(255, 255, 255, 0.82);
  --soft: #eff7ff;
  --page: #f7fbff;
  --shadow: 0 18px 55px rgba(31, 91, 151, 0.11);
  --radius: 24px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  min-width: 320px;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 10% 4%, rgba(48, 184, 226, 0.14), transparent 28rem),
    radial-gradient(circle at 95% 20%, rgba(255, 159, 28, 0.1), transparent 25rem),
    var(--page);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Microsoft YaHei", sans-serif;
  font-size: 16px;
  line-height: 1.72;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--blue-deep);
  text-underline-offset: 3px;
}

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

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 20;
  padding: 8px 14px;
  color: #fff;
  background: var(--blue-deep);
  border-radius: 10px;
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  border-bottom: 1px solid rgba(255, 255, 255, 0.62);
  background: rgba(247, 251, 255, 0.78);
  backdrop-filter: blur(18px) saturate(150%);
  -webkit-backdrop-filter: blur(18px) saturate(150%);
}

.nav,
.container,
.footer-inner {
  width: min(1080px, calc(100% - 40px));
  margin-inline: auto;
}

.nav {
  min-height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 11px;
  color: var(--ink);
  font-weight: 760;
  letter-spacing: -0.02em;
  text-decoration: none;
}

.brand img {
  width: 42px;
  height: 42px;
  border-radius: 12px;
  box-shadow: 0 7px 18px rgba(30, 112, 204, 0.18);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-links a {
  padding: 7px 12px;
  color: var(--muted);
  border-radius: 999px;
  font-size: 14px;
  font-weight: 650;
  text-decoration: none;
}

.nav-links a[aria-current="page"],
.nav-links a:hover {
  color: var(--blue-deep);
  background: rgba(22, 119, 255, 0.09);
}

main {
  padding: 54px 0 80px;
}

.hero {
  position: relative;
  overflow: hidden;
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 40px;
  padding: clamp(30px, 6vw, 64px);
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.94), rgba(231, 246, 255, 0.88));
  border: 1px solid rgba(255, 255, 255, 0.92);
  border-radius: 34px;
  box-shadow: var(--shadow);
}

.hero::after {
  content: "";
  position: absolute;
  width: 270px;
  height: 270px;
  right: -90px;
  bottom: -130px;
  background: radial-gradient(circle, rgba(48, 184, 226, 0.22), transparent 68%);
  pointer-events: none;
}

.eyebrow {
  margin: 0 0 10px;
  color: var(--blue-deep);
  font-size: 13px;
  font-weight: 780;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  max-width: 760px;
  margin-bottom: 16px;
  font-size: clamp(36px, 6vw, 62px);
  line-height: 1.08;
  letter-spacing: -0.045em;
}

.lead {
  max-width: 720px;
  margin-bottom: 0;
  color: var(--muted);
  font-size: clamp(17px, 2.2vw, 20px);
}

.hero-logo {
  position: relative;
  z-index: 1;
  width: clamp(112px, 16vw, 164px);
  height: clamp(112px, 16vw, 164px);
  border: 8px solid rgba(255, 255, 255, 0.82);
  border-radius: 36px;
  box-shadow: 0 20px 42px rgba(41, 104, 174, 0.2);
}

.meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 14px;
}

.meta span {
  display: inline-flex;
  align-items: center;
  gap: 7px;
}

.meta span::before {
  content: "";
  width: 7px;
  height: 7px;
  background: var(--cyan);
  border-radius: 50%;
  box-shadow: 0 0 0 5px rgba(48, 184, 226, 0.11);
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 260px;
  gap: 30px;
  align-items: start;
  margin-top: 34px;
}

.content {
  min-width: 0;
}

.section-card,
.aside-card,
.faq details,
.support-card {
  background: var(--card);
  border: 1px solid rgba(255, 255, 255, 0.88);
  box-shadow: 0 10px 35px rgba(31, 91, 151, 0.07);
}

.section-card {
  margin-bottom: 18px;
  padding: clamp(23px, 4vw, 34px);
  border-radius: var(--radius);
  scroll-margin-top: 95px;
}

.section-heading {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 14px;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(20px, 3vw, 25px);
  line-height: 1.25;
  letter-spacing: -0.025em;
}

.number,
.mini-icon {
  flex: 0 0 auto;
  display: inline-grid;
  width: 36px;
  height: 36px;
  place-items: center;
  color: var(--blue-deep);
  background: rgba(22, 119, 255, 0.1);
  border-radius: 11px;
  font-size: 14px;
  font-weight: 780;
}

.section-card p:last-child,
.section-card ul:last-child {
  margin-bottom: 0;
}

.section-card p,
.section-card li,
.faq p {
  color: var(--muted);
}

.section-card ul {
  padding-left: 1.25em;
}

.section-card li + li {
  margin-top: 8px;
}

.callout {
  padding: 18px 20px;
  color: #15537d;
  background: linear-gradient(135deg, rgba(48, 184, 226, 0.12), rgba(22, 119, 255, 0.08));
  border: 1px solid rgba(48, 184, 226, 0.2);
  border-radius: 16px;
}

.aside {
  position: sticky;
  top: 96px;
}

.aside-card {
  padding: 20px;
  border-radius: 20px;
}

.aside-card + .aside-card {
  margin-top: 14px;
}

.aside-card h2 {
  margin-bottom: 10px;
  font-size: 15px;
}

.aside-card nav {
  display: grid;
  gap: 4px;
}

.aside-card nav a {
  padding: 7px 10px;
  color: var(--muted);
  border-radius: 9px;
  font-size: 14px;
  text-decoration: none;
}

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

.aside-card p {
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 14px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 46px;
  padding: 10px 18px;
  color: #fff;
  background: linear-gradient(135deg, var(--blue), var(--blue-deep));
  border-radius: 14px;
  box-shadow: 0 8px 22px rgba(22, 119, 255, 0.22);
  font-weight: 700;
  text-decoration: none;
}

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

.button.secondary {
  color: var(--blue-deep);
  background: rgba(22, 119, 255, 0.09);
  box-shadow: none;
}

.support-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
  margin: 34px 0;
}

.support-card {
  padding: 26px;
  border-radius: var(--radius);
}

.support-card h2 {
  margin: 14px 0 8px;
  font-size: 20px;
}

.support-card p {
  margin-bottom: 0;
  color: var(--muted);
}

.faq {
  margin-top: 34px;
}

.faq > h2 {
  margin-bottom: 16px;
  font-size: 28px;
  letter-spacing: -0.03em;
}

.faq details {
  margin-bottom: 12px;
  border-radius: 18px;
}

.faq summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  padding: 20px 22px;
  cursor: pointer;
  font-weight: 700;
  list-style: none;
}

.faq summary::-webkit-details-marker {
  display: none;
}

.faq summary::after {
  content: "+";
  flex: 0 0 auto;
  color: var(--blue);
  font-size: 24px;
  font-weight: 400;
  line-height: 1;
}

.faq details[open] summary::after {
  content: "−";
}

.faq details p {
  margin: -6px 22px 0;
  padding: 0 0 22px;
}

.contact-panel {
  margin-top: 34px;
  padding: clamp(28px, 5vw, 48px);
  text-align: center;
  background: linear-gradient(135deg, #e8f7ff, #f9fcff 62%, #fff4e6);
  border: 1px solid rgba(48, 184, 226, 0.16);
  border-radius: 30px;
  box-shadow: var(--shadow);
}

.contact-panel h2 {
  margin: 12px 0 8px;
  font-size: clamp(25px, 4vw, 34px);
}

.contact-panel p {
  max-width: 620px;
  margin: 0 auto 22px;
  color: var(--muted);
}

.contact-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 10px;
}

.site-footer {
  padding: 26px 0 40px;
  border-top: 1px solid var(--line);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  color: var(--muted);
  font-size: 13px;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.footer-links a {
  color: inherit;
  text-decoration: none;
}

@media (prefers-color-scheme: dark) {
  :root {
    --blue: #62b5ff;
    --blue-deep: #8bcaff;
    --ink: #eaf4ff;
    --muted: #a7bad0;
    --line: rgba(157, 203, 244, 0.13);
    --card: rgba(17, 42, 68, 0.82);
    --soft: rgba(49, 137, 218, 0.13);
    --page: #07182a;
    --shadow: 0 18px 55px rgba(0, 0, 0, 0.22);
  }

  body {
    background:
      radial-gradient(circle at 10% 4%, rgba(48, 184, 226, 0.13), transparent 28rem),
      radial-gradient(circle at 95% 20%, rgba(255, 159, 28, 0.07), transparent 25rem),
      var(--page);
  }

  .site-header {
    border-bottom-color: rgba(116, 179, 228, 0.1);
    background: rgba(7, 24, 42, 0.78);
  }

  .hero {
    background: linear-gradient(135deg, rgba(18, 48, 77, 0.96), rgba(12, 39, 65, 0.9));
    border-color: rgba(111, 182, 235, 0.12);
  }

  .section-card,
  .aside-card,
  .faq details,
  .support-card {
    border-color: rgba(111, 182, 235, 0.1);
  }

  .callout {
    color: #b9e9ff;
  }

  .button:not(.secondary) {
    color: #07182a;
    background: linear-gradient(135deg, #72d4f3, #68b4ff);
  }

  .button:not(.secondary):hover {
    color: #07182a;
  }

  .contact-panel {
    background: linear-gradient(135deg, rgba(24, 76, 109, 0.68), rgba(14, 43, 69, 0.9));
    border-color: rgba(91, 186, 231, 0.16);
  }
}

@media (max-width: 800px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .aside {
    position: static;
    order: -1;
  }

  .aside-card:first-child {
    display: none;
  }
}

@media (max-width: 620px) {
  .nav,
  .container,
  .footer-inner {
    width: min(100% - 28px, 1080px);
  }

  .nav {
    min-height: 64px;
  }

  .brand img {
    width: 38px;
    height: 38px;
  }

  .nav-links a {
    padding: 7px 9px;
    font-size: 13px;
  }

  main {
    padding-top: 26px;
  }

  .hero {
    grid-template-columns: 1fr;
    gap: 24px;
    border-radius: 26px;
  }

  .hero-logo {
    grid-row: 1;
    width: 88px;
    height: 88px;
    border-width: 5px;
    border-radius: 24px;
  }

  h1 {
    font-size: 38px;
  }

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

  .footer-inner {
    align-items: flex-start;
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition: none !important;
  }
}