:root {
  color-scheme: dark;
  --ink: #f0f8fc;
  --ink-muted: #bdd3df;
  --gold: #83b5cf;
  --gold-soft: #c5e0ef;
  --paper: #062d45;
  --paper-deep: #06263c;
  --ocean-edge: clamp(24px, 7vw, 112px);
}

html { scrollbar-color: #83b5cf #06263c; }
body { background: var(--paper); isolation: isolate; }
::selection { background: #b7deef; color: #06263c; }
a { text-underline-offset: 5px; }
a:focus-visible { outline: 2px solid #b7deef; outline-offset: 6px; }
.skip-link { background: var(--paper-deep); color: var(--ink); }
.site-header { padding: 28px var(--ocean-edge); color: var(--ink); background: linear-gradient(180deg, #06263c91, #06263c00); }
.brand { filter: none; animation: none; gap: 12px; }
.brand-mark { width: 30px; height: 30px; color: var(--ink); }
.brand-name { font-size: 21px; font-weight: 400; letter-spacing: .08em; }
.site-nav { display: flex; align-items: center; gap: clamp(22px, 3vw, 44px); }
.site-nav a { display: inline-flex; align-items: center; min-height: 44px; padding: 8px 2px; font-size: 14px; text-decoration: none; text-shadow: 0 1px 4px rgb(0 0 0 / 45%); }
.site-nav a:hover { text-decoration: underline; }

.ocean-journey { position: relative; }
.ocean-stage { position: fixed; z-index: 0; inset: 0; height: 100dvh; overflow: hidden; isolation: isolate; background: var(--paper); pointer-events: none; }
.ocean-stage::before { content: ""; position: absolute; z-index: 1; inset: 0; background: rgb(6 38 60 / 76%); opacity: var(--content-wash, 0); }
/* 首屏不叠加随滚动淡出的暗幕，海面与下潜初段使用同一亮度基准。 */
.ocean-poster, .ocean-video, .ocean-surface { position: absolute; inset: 0; display: block; width: 100%; height: 100%; max-width: none; object-fit: cover; object-position: center; }
.ocean-video { opacity: 0; }
.has-ocean-frame .ocean-video { opacity: 1; }
.ocean-surface { opacity: 0; transition: opacity 220ms ease-out; }
.has-surface-frame.surface-active .ocean-surface { opacity: 1; }
.ocean-intro { position: relative; z-index: 2; height: 100svh; }
.dive-enabled .ocean-intro { height: 90svh; }
.ocean-cover { position: relative; height: 100svh; opacity: var(--opening-opacity, 1); }
.ocean-opening { position: absolute; top: clamp(165px, 24svh, 280px); left: var(--ocean-edge); right: var(--ocean-edge); transform: translateY(var(--opening-shift, 0px)); pointer-events: none; }
.ocean-title { margin: 0; color: var(--ink); font: 400 clamp(52px, 7.1vw, 96px)/1.12 var(--serif); letter-spacing: .04em; text-shadow: 0 2px 14px rgb(0 0 0 / 45%); }
.ocean-tagline { display: inline-block; margin: 24px 0 0; padding: 4px 10px; border-radius: 4px; background: #06263cc7; color: var(--ink); font-size: 14px; line-height: 1.65; }
.ocean-bottom { position: absolute; z-index: 2; bottom: max(52px, env(safe-area-inset-bottom)); left: var(--ocean-edge); right: var(--ocean-edge); display: flex; align-items: center; justify-content: space-between; gap: 24px; }
.ocean-enter { display: inline-flex; align-items: center; gap: 12px; min-height: 44px; color: var(--ink); font-size: 14px; text-decoration: none; text-shadow: 0 1px 2px rgb(1 20 31 / 95%), 0 3px 10px rgb(1 20 31 / 75%); }
.ocean-enter:hover { text-decoration: underline; }
.ocean-motion { min-height: 44px; padding: 8px 12px; border: 1px solid #83b5cf88; border-radius: 4px; color: var(--ink); background: #06263cc7; font: 400 13px/1.6 var(--sans); cursor: pointer; }
.ocean-motion:hover { background: #06263c; }
.ocean-motion:focus-visible { outline: 2px solid #b7deef; outline-offset: 6px; }
.ocean-motion[hidden] { display: none; }
.ocean-enter svg, .site-footer svg { width: 20px; height: 20px; stroke: currentColor; stroke-width: 1.5; stroke-linecap: round; stroke-linejoin: round; flex: 0 0 auto; }
.ocean-progress { position: absolute; z-index: 2; left: var(--ocean-edge); bottom: 32px; width: min(58vw, 720px); height: 1px; background: #f0f8fc50; }
.ocean-progress span { display: block; width: 100%; height: 100%; background: var(--ink); transform: scaleX(var(--dive-progress, 0)); transform-origin: left; }
.ocean-status { position: absolute; z-index: 2; left: var(--ocean-edge); bottom: 112px; max-width: calc(100% - 2 * var(--ocean-edge)); margin: 0; padding: 6px 10px; background: #06263ce8; color: var(--ink); border-radius: 4px; font-size: 13px; line-height: 1.6; }
.ocean-status[hidden] { display: none; }
.ocean-dive-status { position: fixed; z-index: 4; bottom: max(24px, env(safe-area-inset-bottom)); pointer-events: none; }

.section-shell { padding-inline: var(--ocean-edge); }
.ocean-content { position: relative; z-index: 3; opacity: var(--content-opacity, 1); }
.ocean-content[inert] { pointer-events: none; }
html:not(.dive-enabled) .ocean-intro { z-index: 4; }
html:not(.dive-enabled) .ocean-content::before { content: ""; position: absolute; z-index: -1; inset: -240px 0 0; background: linear-gradient(180deg, rgb(6 38 60 / 0%) 0, rgb(6 38 60 / 76%) 240px, rgb(6 38 60 / 76%) 100%); pointer-events: none; }
.about { background: transparent; }
.about-grid { margin-top: 0; }
.about h2 { margin: 0; font: 400 clamp(36px, 4.6vw, 68px)/1.3 var(--serif); letter-spacing: .02em; }
.about-copy { max-width: 65ch; }
.about-copy p { color: var(--ink-muted); }
.catalogue { padding-top: 0; background: transparent; }
.catalogue-heading { margin-top: 0; }
.catalogue-heading h2 { font-weight: 400; }
.catalogue-row { grid-template-columns: minmax(0, 1fr) auto; border-color: #83b5cf55; scroll-margin-top: 36px; }
.catalogue-row:last-child { border-color: #83b5cf55; }
.catalogue-row:target { background: transparent; }
.catalogue-row:target .catalogue-body h3 { text-decoration: underline; text-decoration-color: var(--gold-soft); text-underline-offset: 9px; }
.catalogue-status { grid-column: auto; color: var(--ink-muted); border: 0; padding: 0; letter-spacing: 0; }
.catalogue-body h3 { font-weight: 400; }
.site-footer { background: transparent; color: var(--ink-muted); padding-inline: var(--ocean-edge); letter-spacing: 0; }
.site-footer span:first-child { color: var(--ink); font-weight: 400; }
.site-footer a { display: inline-flex; align-items: center; gap: 10px; min-height: 44px; }
.site-footer a:hover { color: var(--ink); }

@media (max-width: 700px) {
  .site-header { padding-block: 22px; }
  .brand { gap: 8px; }
  .brand-mark { width: 24px; height: 24px; }
  .brand-name { font-size: 18px; letter-spacing: .04em; }
  .site-nav { gap: 16px; }
  .site-nav a { font-size: 13px; }
  .ocean-poster, .ocean-video, .ocean-surface { object-position: 75% center; }
  .ocean-opening { top: 24svh; }
  .ocean-title { font-size: clamp(48px, 14vw, 68px); }
  .ocean-tagline { margin-top: 18px; font-size: 13px; }
  .ocean-bottom { bottom: max(60px, env(safe-area-inset-bottom)); gap: 12px; }
  .ocean-enter { font-size: 13px; gap: 8px; }
  .ocean-motion { font-size: 12px; }
  .ocean-progress { width: 55vw; bottom: 38px; }
  .about-grid { grid-template-columns: 1fr; gap: 32px; }
  .catalogue-heading { align-items: start; flex-direction: column; gap: 18px; margin-bottom: 40px; }
  .catalogue-row { gap: 18px; min-height: 158px; }
  .catalogue-body p { font-size: 14px; }
  .catalogue-status { grid-column: 1; font-size: 12px; }
  .catalogue-row { grid-template-columns: 1fr; gap: 14px; padding-block: 26px; }
  .site-footer { flex-wrap: wrap; gap: 18px; padding-block: 28px; }
  .site-footer a { margin-left: auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .dive-enabled .ocean-intro { height: 100svh; }
  .ocean-opening { transform: none; opacity: 1; }
  .ocean-content { opacity: 1; }
  .ocean-surface { transition: none; }
  .ocean-progress { display: none; }
}