:root {
  color-scheme: dark;
  font-family: "Noto Serif SC", "Songti SC", "STSong", serif;
  background: #020715;
}

* { box-sizing: border-box; }

html, body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
}

body { background: #020715; }

.hero {
  --turn: 0deg;
  --stage-x: 0px;
  --stage-y: 0px;
  --stage-scale: 1;
  position: relative;
  width: 100vw;
  height: 100svh;
  min-height: 620px;
  overflow: hidden;
  isolation: isolate;
  background: #020715;
  color: #effbff;
}

.visual-stage {
  position: absolute;
  left: var(--stage-x);
  top: var(--stage-y);
  width: 1672px;
  height: 941px;
  transform: scale(var(--stage-scale));
  transform-origin: 0 0;
  pointer-events: none;
}

.scene-picture {
  position: absolute;
  inset: 0;
  display: block;
}

.scene {
  position: absolute;
  inset: 0;
  width: 1672px;
  height: 941px;
  transition: opacity .68s cubic-bezier(.22,.61,.19,1), filter .68s ease;
  will-change: opacity, filter;
}

.scene__background {
  position: absolute;
  inset: 0;
  width: 1672px;
  height: 941px;
  object-fit: fill;
  user-select: none;
  pointer-events: none;
}

.scene--tech { opacity: 1; z-index: 1; }
.scene--art { opacity: 0; z-index: 2; filter: brightness(.85); }

.scene--tech::after,
.scene--art::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
}

.scene--tech::after {
  z-index: 4;
  clip-path: inset(69% 0 0);
  background: linear-gradient(102deg, transparent 32%, rgba(105,234,255,0) 42%, rgba(174,245,255,.28) 50%, rgba(105,234,255,0) 58%, transparent 68%);
  mix-blend-mode: screen;
  transform: translateX(-118%);
  animation: techReflection 10s cubic-bezier(.35,.04,.25,1) infinite;
}

.scene--art::after {
  z-index: 4;
  clip-path: circle(32% at 72.5% 43%);
  background: linear-gradient(104deg, transparent 35%, rgba(177,229,255,0) 45%, rgba(255,255,255,.42) 50%, rgba(167,225,255,0) 55%, transparent 65%);
  mix-blend-mode: screen;
  transform: translateX(-115%);
  animation: prismSweep 12s cubic-bezier(.35,.04,.25,1) infinite 1.8s;
}

.hero[data-scene="art"] .scene--tech { opacity: 0; filter: brightness(1.25); }
.hero[data-scene="art"] .scene--art { opacity: 1; filter: brightness(1); }

.tech-ring-motion {
  position: absolute;
  z-index: 2;
  left: 883px;
  top: 83px;
  width: 670px;
  height: 670px;
}

.tech-ring {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  pointer-events: none;
  filter: saturate(1.08) drop-shadow(0 0 13px rgba(0,157,255,.46));
  mix-blend-mode: screen;
}

.tech-hill-picture {
  position: absolute;
  z-index: 3;
  inset: 0;
  pointer-events: none;
}

.tech-hill {
  display: block;
  width: 1672px;
  height: 941px;
  object-fit: fill;
  pointer-events: none;
}

.rotating-ring {
  transform: rotate(var(--turn));
  transform-origin: 50% 50%;
  transition: transform 1s cubic-bezier(.16,.78,.18,1);
  will-change: transform;
}

.ring-ambient {
  transform-origin: 50% 50%;
  animation: ambientRing 34s linear infinite;
  will-change: transform;
}

.ring-ambient--art { animation-duration: 42s; animation-direction: reverse; }

.art-ring-motion {
  position: absolute;
  z-index: 3;
  left: 918px;
  top: 118px;
  width: 603px;
  height: 603px;
}

.art-ring {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  pointer-events: none;
}

.loading-intro {
  position: absolute;
  z-index: 30;
  inset: 0;
  display: grid;
  place-items: center;
  overflow: hidden;
  background: #020715;
  color: #eafaff;
  transition: opacity .7s cubic-bezier(.22,.61,.19,1), visibility 0s linear .7s;
}

.loading-intro__ring {
  position: absolute;
  width: min(23vw, 300px);
  aspect-ratio: 1;
  border: 1px solid rgba(89,223,255,.46);
  border-radius: 50%;
  box-shadow: 0 0 26px rgba(41,194,255,.18), inset 0 0 24px rgba(41,194,255,.08);
  animation: introRing 2.2s cubic-bezier(.16,.78,.18,1) infinite;
}

.loading-intro__ring::before,
.loading-intro__ring::after {
  content: "";
  position: absolute;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: #c9faff;
  box-shadow: 0 0 16px #42dfff;
}

.loading-intro__ring::before { top: -4px; left: 50%; }
.loading-intro__ring::after { right: 8%; bottom: 8%; }

.loading-intro__copy {
  position: relative;
  z-index: 1;
  text-align: center;
  animation: introCopy 1.5s cubic-bezier(.22,.61,.19,1) both;
}

.loading-intro__copy p,
.loading-intro__copy h1,
.loading-intro__copy span { margin: 0; display: block; }
.loading-intro__copy p { font: 400 clamp(13px, .9vw, 17px)/1 "Microsoft YaHei", sans-serif; letter-spacing: .52em; opacity: .66; }
.loading-intro__copy h1 { margin: 18px 0 16px; font-size: clamp(38px, 4vw, 70px); font-weight: 400; letter-spacing: .22em; }
.loading-intro__copy span { font: 500 9px/1 Arial, sans-serif; letter-spacing: .55em; opacity: .54; }

.hero--ready .loading-intro { opacity: 0; visibility: hidden; pointer-events: none; }

.site-header {
  position: absolute;
  z-index: 10;
  top: clamp(28px, 4.25vh, 52px);
  left: 7.15vw;
  right: 7.15vw;
  display: grid;
  grid-template-columns: 190px 1fr 190px;
  align-items: start;
  color: currentColor;
  transition: color 1.35s ease;
}

.brand {
  width: max-content;
  color: inherit;
  text-decoration: none;
  text-align: center;
}

.brand__cn {
  display: block;
  font-size: clamp(19px, 1.35vw, 27px);
  letter-spacing: .16em;
  line-height: 1;
}

.brand__en {
  display: block;
  margin-top: 8px;
  font: 500 8px/1 Arial, sans-serif;
  letter-spacing: .42em;
}

.site-nav {
  grid-column: 2;
  display: flex;
  justify-content: center;
  gap: clamp(28px, 3vw, 56px);
  font-family: "Microsoft YaHei", sans-serif;
  font-size: clamp(13px, .8vw, 16px);
}

.site-nav a {
  position: relative;
  padding: 2px 2px 16px;
  color: inherit;
  text-decoration: none;
  white-space: nowrap;
}

.site-nav a::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: 0;
  width: 0;
  height: 1px;
  background: #30dbff;
  transform: translateX(-50%);
  box-shadow: 0 0 9px #30dbff;
  transition: width .35s ease;
}

.site-nav a:hover::after,
.site-nav a.is-active::after { width: 100%; }

.hero-copy {
  position: absolute;
  z-index: 8;
  left: 10.9vw;
  top: 48.5%;
  width: 48vw;
  transform: translateY(-50%);
  transition: opacity 1s ease, transform 1.35s cubic-bezier(.22,.61,.19,1), color 1.2s ease;
}

.hero-copy--tech { opacity: 1; }
.hero-copy--art { opacity: 0; transform: translateY(calc(-50% + 24px)); color: #183b67; }
.hero[data-scene="art"] .hero-copy--tech { opacity: 0; transform: translateY(calc(-50% - 24px)); }
.hero[data-scene="art"] .hero-copy--art { opacity: 1; transform: translateY(-50%); }

.hero-copy__eyebrow {
  margin: 0 0 20px;
  font: 500 clamp(9px, .68vw, 13px)/1.2 Arial, sans-serif;
  letter-spacing: .36em;
  opacity: .62;
}

.hero-copy h1 {
  margin: 0;
  font-size: clamp(46px, 4.25vw, 82px);
  font-weight: 400;
  line-height: 1.12;
  letter-spacing: .12em;
  white-space: nowrap;
  text-shadow: 0 0 24px rgba(109,207,255,.36);
}

.hero-copy--art h1 { text-shadow: 0 5px 24px rgba(74,110,158,.12); }

.hero-copy__sub {
  display: flex;
  align-items: center;
  gap: 20px;
  width: max-content;
  margin: 32px 0 0;
  font-size: clamp(17px, 1.35vw, 26px);
  letter-spacing: .28em;
}

.hero-copy__sub::after {
  content: "";
  width: 150px;
  height: 1px;
  background: currentColor;
  opacity: .4;
}

.hero-copy__en {
  margin: 17px 0 0;
  font: 400 clamp(9px, .64vw, 12px)/1.4 Arial, sans-serif;
  letter-spacing: .3em;
  opacity: .56;
}

.phase-control {
  position: absolute;
  z-index: 12;
  left: 50%;
  bottom: clamp(28px, 4.6vh, 54px);
  display: grid;
  grid-template-columns: 38px 106px 38px;
  grid-template-rows: 38px auto;
  align-items: center;
  gap: 0 8px;
  transform: translateX(-50%);
  font-family: "Microsoft YaHei", sans-serif;
  color: currentColor;
  transition: color 1.2s ease;
}

.phase-control__button {
  width: 38px;
  height: 38px;
  border: 1px solid currentColor;
  border-radius: 50%;
  background: rgba(5,21,48,.18);
  color: inherit;
  font: 300 25px/32px Arial, sans-serif;
  cursor: pointer;
  opacity: .75;
  backdrop-filter: blur(8px);
}

.phase-control__track {
  height: 1px;
  background: currentColor;
  opacity: .28;
  overflow: hidden;
}

.phase-control__progress {
  display: block;
  width: 25%;
  height: 100%;
  background: #35dcff;
  transform: translateX(0);
  transition: transform 1.2s cubic-bezier(.22,.61,.19,1);
  box-shadow: 0 0 9px #35dcff;
}

.phase-control__hint {
  grid-column: 1 / -1;
  margin-top: 10px;
  text-align: center;
  font-size: 10px;
  letter-spacing: .24em;
  opacity: .55;
}

.scene-index {
  position: absolute;
  z-index: 10;
  right: 4.2vw;
  top: 50%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  transform: translateY(-50%);
  font: 10px/1 Arial, sans-serif;
  color: currentColor;
  opacity: .62;
  transition: color 1.2s ease;
}

.scene-index__current { font-size: 14px; }
.scene-index__line { width: 1px; height: 54px; background: currentColor; opacity: .45; }

.transition-veil {
  position: absolute;
  z-index: 7;
  inset: 0;
  opacity: 0;
  pointer-events: none;
  background: radial-gradient(circle at 72.5% 41.8%, rgba(211,245,255,.45), transparent 24%);
  transition: opacity .75s ease;
}

.hero.is-switching .transition-veil { animation: veil .68s ease both; }

.hero[data-scene="art"] { color: #183b67; }
.hero[data-scene="art"] .phase-control__button { background: rgba(255,255,255,.45); }
.hero[data-scene="art"] .phase-control__progress { background: #278bd9; box-shadow: 0 0 8px rgba(39,139,217,.5); }

@keyframes veil {
  0%, 100% { opacity: 0; }
  45% { opacity: .72; }
}

@keyframes ambientRing {
  to { transform: rotate(360deg); }
}

@keyframes techReflection {
  0%, 28% { transform: translateX(-118%); opacity: 0; }
  38% { opacity: .5; }
  57% { transform: translateX(118%); opacity: .36; }
  68%, 100% { transform: translateX(118%); opacity: 0; }
}

@keyframes prismSweep {
  0%, 34% { transform: translateX(-115%); opacity: 0; }
  43% { opacity: .42; }
  58% { transform: translateX(115%); opacity: .3; }
  70%, 100% { transform: translateX(115%); opacity: 0; }
}

@keyframes introRing {
  0% { transform: rotate(0deg) scale(.92); opacity: .12; }
  32% { opacity: .92; }
  100% { transform: rotate(360deg) scale(1.08); opacity: .2; }
}

@keyframes introCopy {
  from { opacity: 0; transform: translateY(14px); }
  to { opacity: 1; transform: translateY(0); }
}

@media (max-aspect-ratio: 4/3) {
  .site-header { left: 5vw; right: 5vw; grid-template-columns: auto 1fr; }
  .site-nav { justify-content: flex-end; gap: 24px; }
  .hero-copy { left: 7vw; top: 45%; width: 58vw; }
  .hero-copy h1 { font-size: clamp(38px, 6vw, 64px); }
}

@media (max-width: 780px) {
  .hero { min-height: 560px; }
  .site-header { grid-template-columns: 1fr; }
  .site-nav { display: none; }
  .hero-copy { left: 7vw; top: 30%; width: 86vw; }
  .hero-copy h1 { font-size: clamp(30px, 9vw, 48px); letter-spacing: .04em; }
  .hero-copy__sub { margin-top: 20px; font-size: 15px; }
  .hero-copy__sub::after { width: 52px; }
  .scene-index { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}