:root {
  color-scheme: dark;
  --bg: #12151b;
  --surface: #191d25;
  --line: rgba(141, 151, 171, 0.22);
  --text: #f5f7fb;
  --muted: #a4adbd;
  --accent: #7bb8ff;
  --accent-strong: #4397f2;
  --font: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; background: var(--bg); color: var(--text); font-family: var(--font); letter-spacing: 0; }
a { color: inherit; }
.support-header, main, .support-footer { width: min(1120px, calc(100% - 40px)); margin-inline: auto; }
.support-header { min-height: 76px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); }
.brand { display: inline-flex; align-items: center; gap: 11px; color: var(--text); font-size: 1.12rem; font-weight: 800; text-decoration: none; }
.brand img { width: 40px; height: 40px; object-fit: contain; }
.support-header nav { display: flex; gap: 28px; }
.support-header nav a { color: var(--muted); font-size: 0.92rem; text-decoration: none; transition: color 160ms ease; }
.support-header nav a:hover { color: var(--text); }
.support-hero { min-height: min(620px, calc(100svh - 76px)); display: grid; grid-template-columns: minmax(0, 1.15fr) minmax(260px, 0.85fr); align-items: center; gap: clamp(48px, 8vw, 112px); border-bottom: 1px solid var(--line); }
.hero-copy { animation: rise-in 520ms ease-out both; }
.eyebrow, .section-index { margin: 0; color: var(--accent); font-size: 0.78rem; font-weight: 800; }
h1 { margin: 18px 0 20px; font-size: clamp(3rem, 7vw, 6rem); line-height: 1.02; letter-spacing: 0; }
.hero-lead { max-width: 580px; margin: 0; color: var(--muted); font-size: 1.1rem; line-height: 1.9; }
.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 34px; }
.hero-actions a { min-height: 46px; padding: 0 19px; display: inline-flex; align-items: center; justify-content: center; border-radius: 6px; font-weight: 750; text-decoration: none; transition: transform 160ms ease, border-color 160ms ease, background 160ms ease; }
.hero-actions a:hover { transform: translateY(-2px); }
.primary-action { background: var(--accent-strong); border: 1px solid var(--accent-strong); color: #08121e; }
.secondary-action { border: 1px solid var(--line); color: var(--text); }
.secondary-action:hover { border-color: rgba(123, 184, 255, 0.62); background: rgba(123, 184, 255, 0.06); }
.hero-mark { width: min(100%, 390px); height: auto; justify-self: end; filter: drop-shadow(0 28px 48px rgba(0, 0, 0, 0.28)); animation: mark-in 640ms 80ms ease-out both; }
.support-section { padding: 104px 0; border-bottom: 1px solid var(--line); }
.section-heading { display: grid; grid-template-columns: 92px minmax(0, 1fr); margin-bottom: 50px; }
h2 { margin: 0 0 10px; font-size: clamp(2rem, 4vw, 3.2rem); line-height: 1.15; letter-spacing: 0; }
.section-heading p:last-child, .contact-copy > p:last-child { margin: 0; color: var(--muted); line-height: 1.8; }
.steps { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.steps li { min-height: 144px; display: grid; grid-template-columns: 92px minmax(0, 1fr); align-items: start; padding: 30px 0; border-bottom: 1px solid var(--line); }
.step-number { color: var(--accent); font-size: 0.88rem; font-weight: 800; }
.steps h3 { margin: 0 0 8px; font-size: 1.16rem; }
.steps p { max-width: 720px; margin: 0; color: var(--muted); line-height: 1.85; }
.faq-list { border-top: 1px solid var(--line); }
.faq-list details { border-bottom: 1px solid var(--line); }
.faq-list summary { min-height: 76px; padding: 23px 46px 23px 0; position: relative; cursor: pointer; font-size: 1.04rem; font-weight: 700; list-style: none; }
.faq-list summary::-webkit-details-marker { display: none; }
.faq-list summary::after { content: "+"; position: absolute; top: 19px; right: 2px; color: var(--accent); font-size: 1.55rem; font-weight: 400; transition: transform 180ms ease; }
.faq-list details[open] summary::after { transform: rotate(45deg); }
.faq-list details p { max-width: 760px; margin: -4px 0 26px; color: var(--muted); line-height: 1.85; }
.contact-section { display: grid; grid-template-columns: 0.82fr 1.18fr; gap: clamp(60px, 9vw, 120px); }
.contact-copy h2 { margin-top: 15px; }
.contact-methods { border-top: 1px solid var(--line); }
.contact-methods a { min-height: 106px; padding: 24px 4px; display: flex; flex-direction: column; justify-content: center; gap: 8px; border-bottom: 1px solid var(--line); text-decoration: none; transition: padding-left 180ms ease, color 180ms ease; }
.contact-methods a:hover { padding-left: 12px; color: var(--accent); }
.contact-methods span, .policy-links span { color: var(--muted); font-size: 0.82rem; }
.contact-methods strong, .policy-links strong { font-size: clamp(1.08rem, 2vw, 1.42rem); overflow-wrap: anywhere; }
.policy-links { display: grid; grid-template-columns: 1fr 1fr; gap: 1px; margin: 0; background: var(--line); }
.policy-links a { min-height: 168px; padding: 34px; display: flex; flex-direction: column; justify-content: flex-end; gap: 8px; background: var(--surface); text-decoration: none; transition: background 180ms ease; }
.policy-links a:hover { background: #1e2530; }
.support-footer { min-height: 104px; display: flex; align-items: center; justify-content: space-between; color: var(--muted); font-size: 0.88rem; }
.support-footer a { text-decoration: none; }
.support-footer a:hover { color: var(--text); }

@keyframes rise-in { from { transform: translateY(18px); } to { transform: translateY(0); } }
@keyframes mark-in { from { transform: translateY(14px) scale(0.96); } to { transform: translateY(0) scale(1); } }

@media (max-width: 760px) {
  .support-header, main, .support-footer { width: min(100% - 24px, 1120px); }
  .support-header nav { display: none; }
  .support-hero { min-height: auto; grid-template-columns: 1fr; gap: 36px; padding: 72px 0 64px; }
  .hero-mark { width: min(62vw, 250px); justify-self: start; }
  .support-section { padding: 72px 0; }
  .section-heading, .steps li { grid-template-columns: 42px minmax(0, 1fr); }
  .section-heading { margin-bottom: 36px; }
  .contact-section, .policy-links { grid-template-columns: 1fr; }
  .contact-section { gap: 40px; }
  .policy-links a { min-height: 132px; padding: 26px 22px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hero-copy, .hero-mark { animation: none; }
  .hero-actions a, .faq-list summary::after, .contact-methods a, .policy-links a { transition: none; }
}