:root {
  color-scheme: light;
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  color: #172326;
  background: #f5f7f7;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  --accent: #177d92;
  --gutter: clamp(28px, 5.5vw, 100px);
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { min-width: 320px; margin: 0; }
button, a { -webkit-tap-highlight-color: transparent; }
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; vertical-align: middle; }
h1, h2, p { margin: 0; }
a:focus-visible { outline: 2px solid var(--accent); outline-offset: 5px; }
::selection { background: #bce5e5; }
.skip-link { position: fixed; z-index: 40; top: 12px; left: 12px; padding: 10px 15px; color: white; background: #172326; transform: translateY(-160%); }
.skip-link:focus { transform: translateY(0); }
.site-header { position: fixed; z-index: 30; inset: 0 0 auto; height: 74px; background: rgba(245,247,247,.78); backdrop-filter: blur(18px); -webkit-backdrop-filter: blur(18px); }
.header-inner, .footer-inner { width: calc(100% - var(--gutter) * 2); max-width: 1640px; height: 100%; margin: auto; display: flex; justify-content: space-between; align-items: center; gap: 24px; }
.brand { display: inline-flex; align-items: center; gap: 9px; flex-shrink: 0; font-size: 16px; font-weight: 650; white-space: nowrap; }
.brand img { width: 30px; height: 30px; object-fit: contain; }
.site-nav { display: flex; align-items: center; gap: 32px; font-size: 12px; font-weight: 500; }
.site-nav a:hover, .site-footer a:hover, .chapter-next:hover { color: var(--accent); }
.nav-action { display: inline-flex; align-items: center; gap: 12px; padding: 10px 17px; color: white; background: #172326; border-radius: 30px; }
.site-nav .nav-action:hover { color: white; background: #177d92; }
.nav-action span { font-size: 15px; }
.story { position: relative; height: 280svh; background: #f5f7f7; }
.story-lens { height: 240svh; }
.story-field { height: 250svh; }
.story-sticky { position: sticky; top: 0; width: 100%; height: 100svh; min-height: 440px; overflow: hidden; isolation: isolate; }
.scene { position: absolute; z-index: 0; inset: 0; background: #f5f7f7; }
.scene iframe { display: block; width: 100%; height: 100%; border: 0; pointer-events: none; background: #f5f7f7; mix-blend-mode: multiply; }
.story-content { position: absolute; z-index: 2; inset: 0 var(--gutter); max-width: 1640px; margin: auto; pointer-events: none; }
.story-phase { position: absolute; top: clamp(115px, 16svh, 195px); left: 0; width: min(830px, 82%); opacity: 0; visibility: hidden; transform: translateY(10px); }
.story-phase.is-visible { visibility: visible; }
.story-phase a { pointer-events: auto; }
.eyebrow { display: flex; align-items: center; gap: 14px; color: var(--accent); font-size: 11px; line-height: 1.5; font-weight: 650; letter-spacing: .04em; }
.eyebrow span { padding-left: 14px; border-left: 1px solid #b9cccc; color: #607376; font-weight: 450; letter-spacing: .05em; }
.story-phase h1, .story-phase h2 { margin-top: 20px; font-size: clamp(58px, 6.2vw, 94px); line-height: 1.14; font-weight: 640; letter-spacing: -.045em; }
.accent { color: var(--accent); }
.phase-lead { margin-top: 24px; color: #607074; font-size: clamp(14px, 1.15vw, 18px); line-height: 1.85; font-weight: 400; letter-spacing: .01em; }
.main-action { display: inline-flex; align-items: center; justify-content: space-between; gap: 32px; min-height: 47px; margin-top: 24px; padding: 12px 21px; color: white; background: #172326; border-radius: 30px; font-size: 13px; font-weight: 550; }
.main-action:hover { background: var(--accent); }
.main-action span { font-size: 17px; }
.story-bottom { position: absolute; z-index: 3; right: var(--gutter); bottom: 32px; left: var(--gutter); display: flex; align-items: center; justify-content: space-between; gap: 16px; color: #6b7b7e; font-size: 11px; font-weight: 450; }
.scroll-prompt, .chapter-next { display: inline-flex; align-items: center; gap: 13px; }
.scroll-prompt span, .chapter-next span { color: var(--accent); font-size: 17px; }
.chapter-count { color: #28454d; font-size: 13px; font-variant-numeric: tabular-nums; }
.chapter-count span { margin-left: 5px; color: #9aa7aa; font-size: 11px; }
.scroll-track { position: absolute; z-index: 3; right: 0; bottom: 0; left: 0; height: 2px; background: rgba(22,65,75,.08); }
.scroll-track span { display: block; width: 100%; height: 100%; background: #158ba5; transform-origin: left; transform: scaleX(0); }
.site-footer { min-height: 115px; background: #f5f7f7; border-top: 1px solid #dce5e5; }
.footer-inner { min-height: 115px; color: #6b787b; font-size: 11px; }
.site-footer .brand { color: #273337; font-size: 13px; }
.site-footer .brand img { width: 25px; height: 25px; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 28px; }
@media (max-width: 600px) {
  :root { --gutter: 23px; }
  .site-header { height: 62px; }
  .brand { font-size: 14px; gap: 7px; }
  .brand img { width: 26px; height: 26px; }
  .site-nav { gap: 15px; font-size: 11px; }
  .site-nav > a:first-child { display: none; }
  .nav-action { gap: 8px; padding: 9px 14px; }
  .story { height: 270svh; }
  .story-lens, .story-field { height: 230svh; }
  .story-sticky { min-height: 0; }
  .story-phase { top: clamp(108px, 14svh, 155px); width: 100%; max-width: 500px; }
  .story-phase h1, .story-phase h2 { margin-top: 18px; font-size: clamp(40px, 10.7vw, 60px); line-height: 1.2; letter-spacing: -.04em; }
  .phase-lead { margin-top: 18px; max-width: 25em; font-size: 12px; line-height: 1.8; }
  .eyebrow { font-size: 10px; }
  .main-action { min-height: 43px; margin-top: 19px; font-size: 12px; }
  .story-bottom { bottom: 25px; font-size: 9px; gap: 12px; }
  .scroll-prompt, .chapter-next { gap: 7px; }
  .scroll-prompt { max-width: 134px; line-height: 1.7; }
  .chapter-count { font-size: 12px; }
  .chapter-count span { font-size: 9px; }
  .footer-inner { min-height: 125px; flex-wrap: wrap; justify-content: flex-start; padding: 22px 0; gap: 17px 24px; }
  .site-footer nav { order: 3; flex-basis: 100%; gap: 16px; }
  .site-footer .brand { margin-right: auto; }
}
@media (max-height: 700px) and (min-width: 601px) {
  .story-phase { top: 94px; }
  .story-phase h1, .story-phase h2 { margin-top: 15px; font-size: clamp(48px, 6.2vw, 67px); line-height: 1.12; }
  .phase-lead { margin-top: 16px; font-size: 14px; }
  .main-action { margin-top: 17px; }
}
@media (max-height: 500px) and (min-width: 601px) {
  .site-header { height: 56px; }
  .story-phase { top: 70px; }
  .story-phase h1, .story-phase h2 { font-size: 36px; }
  .phase-lead { margin-top: 10px; font-size: 12px; }
  .story-bottom { bottom: 16px; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .story { height: 100svh; }
  .story-phase { transform: none; }
}