:root {
  --seo-bg: #f3f5f1;
  --seo-surface: #fbfcf9;
  --seo-ink: #17201d;
  --seo-muted: #52605b;
  --seo-line: rgba(23, 32, 29, 0.14);
  --seo-accent: #245c4e;
  --seo-accent-strong: #173f35;
  --seo-soft: #dbe9e3;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body { margin: 0; }

.seo-page {
  min-height: 100dvh;
  overflow-x: hidden;
  background: var(--seo-bg);
  color: var(--seo-ink);
  font-family: "SF Pro Display", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
}

.seo-nav,
.seo-hero,
.seo-summary,
.seo-content,
.seo-faq,
.seo-footer {
  width: min(1180px, calc(100% - 40px));
  margin-inline: auto;
}

.seo-nav {
  display: flex;
  min-height: 72px;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border-bottom: 1px solid var(--seo-line);
}

.seo-brand {
  color: var(--seo-ink);
  font-size: 18px;
  font-weight: 800;
  letter-spacing: -0.03em;
  text-decoration: none;
  white-space: nowrap;
}

.seo-brand small { color: var(--seo-muted); font-size: 12px; font-weight: 650; }
.seo-nav > div { display: flex; align-items: center; gap: 24px; }
.seo-nav > div a { color: var(--seo-muted); font-size: 13px; font-weight: 650; text-decoration: none; white-space: nowrap; }
.seo-nav a:hover { color: var(--seo-accent); }

.seo-hero {
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(420px, 1.1fr);
  min-height: min(760px, calc(100dvh - 72px));
  align-items: center;
  gap: clamp(36px, 7vw, 96px);
  padding-block: clamp(48px, 8vw, 88px);
}

.seo-hero-copy { min-width: 0; max-width: 620px; }
.seo-kicker { margin: 0 0 18px; color: var(--seo-accent); font-size: 13px; font-weight: 750; }
.seo-hero h1 { margin: 0; font-size: clamp(42px, 5.2vw, 68px); line-height: 1.03; letter-spacing: -0.06em; text-wrap: balance; }
.seo-hero-copy > p:not(.seo-kicker) { max-width: 36em; margin: 24px 0 0; overflow-wrap: anywhere; color: var(--seo-muted); font-size: 17px; line-height: 1.75; }
.seo-hero > img { display: block; width: 100%; min-width: 0; max-width: 100%; height: auto; border-radius: 16px; box-shadow: 0 28px 80px rgba(26, 47, 40, 0.15); }

.seo-actions { display: flex; align-items: center; gap: 18px; margin-top: 30px; }
.seo-button { display: inline-flex; min-height: 44px; align-items: center; justify-content: center; border-radius: 12px; background: var(--seo-accent-strong); color: #f7faf8; padding: 0 20px; font-size: 14px; font-weight: 750; text-decoration: none; white-space: nowrap; }
.seo-button:hover { transform: translateY(-1px); background: var(--seo-accent); }
.seo-button:active { transform: translateY(1px); }
.seo-text-link { color: var(--seo-accent); font-size: 14px; font-weight: 750; text-underline-offset: 4px; }

.seo-summary { padding-block: 86px 100px; }
.seo-summary > h2 { max-width: 720px; margin: 0 0 46px; font-size: clamp(30px, 4vw, 48px); line-height: 1.12; letter-spacing: -0.045em; }
.seo-summary > div { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 0 72px; }
.seo-summary article { padding: 26px 0; border-top: 1px solid var(--seo-line); }
.seo-summary article:first-child { grid-row: span 2; padding-right: 10%; }
.seo-summary h3 { margin: 0 0 10px; color: var(--seo-accent); font-size: 22px; }
.seo-summary p { max-width: 34em; margin: 0; color: var(--seo-muted); font-size: 15px; line-height: 1.75; }

.seo-topic-hero { min-height: auto; padding-block: 72px 64px; }
.seo-topic-hero h1 { font-size: clamp(40px, 5vw, 64px); }
.seo-content { padding-block: 32px 96px; }
.seo-content-intro { max-width: 780px; margin-bottom: 56px; }
.seo-content h2 { margin: 0 0 18px; font-size: clamp(28px, 3.5vw, 44px); line-height: 1.15; letter-spacing: -0.04em; }
.seo-content p { color: var(--seo-muted); font-size: 16px; line-height: 1.8; }
.seo-process { display: grid; grid-template-columns: minmax(240px, 0.7fr) minmax(0, 1.3fr); gap: 48px 90px; align-items: start; }
.seo-process > h2 { position: sticky; top: 28px; }
.seo-process-list { display: grid; gap: 0; }
.seo-process article { padding: 28px 0; border-top: 1px solid var(--seo-line); }
.seo-process h3 { margin: 0 0 8px; font-size: 22px; }
.seo-process p { margin: 0; }
.seo-callout { display: grid; grid-template-columns: 1fr 0.8fr; gap: 48px; align-items: center; margin-top: 86px; border-radius: 16px; background: var(--seo-accent-strong); color: #f0f6f3; padding: clamp(30px, 5vw, 62px); }
.seo-callout h2 { margin-bottom: 0; color: inherit; }
.seo-callout p { color: #c8d8d2; }
.seo-callout .seo-button { justify-self: end; background: #eff6f3; color: #173f35; }

.seo-faq { padding-block: 20px 96px; }
.seo-faq h2 { margin: 0 0 34px; font-size: clamp(28px, 3vw, 42px); letter-spacing: -0.04em; }
.seo-faq details { border-top: 1px solid var(--seo-line); padding: 22px 0; }
.seo-faq summary { cursor: pointer; font-size: 17px; font-weight: 750; }
.seo-faq p { max-width: 740px; color: var(--seo-muted); line-height: 1.75; }
.seo-footer { display: grid; gap: 22px; border-top: 1px solid var(--seo-line); padding-block: 28px 42px; color: var(--seo-muted); font-size: 12px; }
.seo-footer-main { display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.seo-footer-copy { display: flex; align-items: flex-start; flex-direction: column; gap: 5px; }
.seo-footer-links { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px 18px; }
.seo-footer-registration { display: flex; justify-content: center; width: 100%; }
.seo-footer-registration a { white-space: nowrap; }
.seo-footer a { color: inherit; }
.seo-footer a:hover { color: var(--seo-accent); }

@media (prefers-color-scheme: dark) {
  :root {
    --seo-bg: #000000;
    --seo-surface: #1c1c1e;
    --seo-ink: #f5f5f7;
    --seo-muted: #a1a1a6;
    --seo-line: rgba(255, 255, 255, 0.16);
    --seo-accent: #409cff;
    --seo-accent-strong: #0a84ff;
    --seo-soft: #1f2b3a;
  }
  .seo-hero > img { opacity: 0.9; box-shadow: 0 28px 80px rgba(0, 0, 0, 0.3); }
  .seo-callout { background: #0d3b66; }
}

@media (max-width: 767px) {
  .seo-nav { min-height: 64px; }
  .seo-nav > div { display: none; }
  .seo-hero { grid-template-columns: minmax(0, 1fr); min-height: auto; gap: 34px; padding-block: 48px 60px; }
  .seo-hero h1 { font-size: clamp(38px, 11vw, 54px); }
  .seo-hero > img { border-radius: 12px; }
  .seo-summary { padding-block: 60px 72px; }
  .seo-summary > div, .seo-process, .seo-callout { grid-template-columns: 1fr; gap: 0; }
  .seo-summary article:first-child { grid-row: auto; padding-right: 0; }
  .seo-process > h2 { position: static; margin-bottom: 22px; }
  .seo-callout { gap: 22px; margin-top: 58px; }
  .seo-callout .seo-button { justify-self: start; }
  .seo-footer-main { align-items: flex-start; flex-direction: column; }
  .seo-footer-links { justify-content: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .seo-button { transition: none; }
}