:root {
  --navy: #092b3d;
  --ink: #092b3d;
  --foam: #edf8f7;
  --aqua: #9de5dc;
  --sand: #eec27f;    /* 日出暖沙色：第二强调色，呼应视频里的太阳 */
  --ease: cubic-bezier(.16, 1, .3, 1); /* easeOutExpo：全站统一缓动 */
  /* 4pt 间距刻度 */
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 20px;
  --space-6: 24px;
  --space-7: 28px;
  --line: rgba(9, 43, 61, .2);
  /* 五档字号体系：micro < caption < body < title < display */
  --fs-micro: 10px;   /* 眉题/页脚/标签/深度计等微型大写标注 */
  --fs-caption: 12px; /* 说明文字、按钮、元信息 */
  --fs-body: 14px;    /* 正文 */
  --fs-title: 20px;   /* 卡片标题 */
  --hero-opacity: 1;
  --hero-y: 0px;
  --hero-blur: 0px;
  --dive-opacity: 0;
  --resource-opacity: 0;
  --resource-y: 56px;
  --underwater: 0;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  overflow: hidden;
  color: var(--ink);
  background: #031c29;
  font-family: "DM Sans", "PingFang SC", "Microsoft YaHei", sans-serif;
  -webkit-font-smoothing: antialiased;
}
button, input { font: inherit; }
button, a { -webkit-tap-highlight-color: transparent; }
button { color: inherit; cursor: pointer; }
a { color: inherit; text-decoration: none; }
button:focus-visible, a:focus-visible, input:focus-visible {
  outline: 2px solid #8de4dc;
  outline-offset: 4px;
}
::selection { color: #082c41; background: var(--sand); }

.page-progress {
  position: fixed;
  z-index: 100;
  top: 0;
  left: 0;
  width: 100%;
  height: 2px;
  pointer-events: none;
}
.page-progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: #b8f3e8;
  transform: scaleX(0);
  transform-origin: left;
}

.ocean-journey { height: 100vh; height: 100svh; }
.ocean-stage {
  position: relative;
  top: 0;
  height: 100vh;
  height: 100svh;
  min-height: 600px;
  overflow: hidden;
  isolation: isolate;
  background: #06384a;
  color: var(--ink);
  transition: color .7s var(--ease);
}
.ocean-stage.is-underwater { --ink: #edf8f7; --line: rgba(237, 248, 247, .22); }
.ocean-video {
  position: absolute;
  z-index: -6;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 50% 50%;
  transform: scale(1.2);
  filter: saturate(.85) contrast(1.02);
  transition: opacity .45s var(--ease);
}
.dive-video {
  z-index: -4;
  opacity: 0;
  pointer-events: none;
  transition: opacity .5s var(--ease);
}
.underwater-video {
  z-index: -4;
  opacity: 0;
  pointer-events: none;
  transition: opacity .5s var(--ease);
}
.stage-diving .dive-video { opacity: 1; }
.stage-diving .ocean-video:not(.dive-video) { opacity: 0; }
/* 下潜完成后，切到水下循环视频，保持持续涌动 */
.is-resources .underwater-video { opacity: 1; }
.is-resources .ocean-video:not(.underwater-video) { opacity: 0; }
.is-resources .underwater-video {
  animation: ocean-float 18s ease-in-out infinite alternate;
}
@keyframes ocean-float {
  from { transform: scale(1.2) translate3d(0, 0, 0); }
  to { transform: scale(1.22) translate3d(-1.2%, -1.4%, 0); }
}
.ocean-color {
  position: absolute;
  z-index: -5;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(90deg, rgba(227, 241, 238, .16) 0%, transparent 48%),
    linear-gradient(180deg, rgba(5, 27, 39, .04), transparent 56%, rgba(2, 29, 41, .18));
  transition: opacity .6s var(--ease);
}
.is-underwater .ocean-color {
  background:
    linear-gradient(90deg, rgba(1, 23, 35, .32), transparent 56%),
    linear-gradient(180deg, rgba(0, 22, 34, .12), rgba(0, 20, 31, .48));
}
.ocean-grain {
  position: absolute;
  z-index: 20;
  inset: -50%;
  opacity: .06;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.8'/%3E%3C/svg%3E");
  animation: grain .24s steps(2) infinite;
}
@keyframes grain {
  0% { transform: translate(0, 0); }
  25% { transform: translate(2%, -3%); }
  50% { transform: translate(-3%, 2%); }
  75% { transform: translate(3%, 4%); }
  100% { transform: translate(-2%, -4%); }
}
.light-rays {
  position: absolute;
  z-index: -3;
  inset: 0;
  opacity: var(--underwater);
  overflow: hidden;
  pointer-events: none;
  mix-blend-mode: screen;
  transition: opacity 1.1s var(--ease);
}
.light-rays i {
  position: absolute;
  top: -28%;
  width: 11%;
  height: 130%;
  background: linear-gradient(180deg, rgba(179, 240, 230, .28), transparent 76%);
  filter: blur(18px);
  transform: rotate(-24deg);
  transform-origin: top;
  animation: rays 7s ease-in-out infinite alternate;
}
.light-rays i:nth-child(1) { left: 58%; }
.light-rays i:nth-child(2) { left: 72%; width: 5%; animation-delay: -2.4s; }
.light-rays i:nth-child(3) { left: 88%; width: 17%; animation-delay: -4.8s; }
@keyframes rays {
  from { transform: rotate(-24deg) translateX(0); opacity: .5; }
  to { transform: rotate(-17deg) translateX(70px); opacity: .9; }
}
.bubbles { position: absolute; z-index: -2; inset: 0; pointer-events: none; opacity: var(--underwater); transition: opacity 1.1s var(--ease); }
.bubble {
  position: absolute;
  bottom: -30px;
  width: 4px;
  height: 4px;
  border: 1px solid rgba(213, 249, 246, .5);
  border-radius: 50%;
  animation: bubble-rise linear infinite;
}
@keyframes bubble-rise {
  from { transform: translate3d(0, 0, 0); opacity: 0; }
  12% { opacity: .65; }
  to { transform: translate3d(45px, -110vh, 0); opacity: 0; }
}

.announcement {
  position: absolute;
  z-index: 5;
  top: 0;
  left: 0;
  right: 0;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  border-bottom: 1px solid var(--line);
  font-size: var(--fs-caption);
  letter-spacing: .12em;
  transition: opacity .4s var(--ease);
}
.announcement a { opacity: .85; }
.announcement a:hover { opacity: 1; }
.is-underwater .announcement { opacity: 0; pointer-events: none; }
.site-header {
  position: absolute;
  z-index: 6;
  top: 32px;
  left: 0;
  right: 0;
  height: 86px;
  padding: 0 4.2vw;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
}
.brand { display: inline-flex; align-items: center; gap: 12px; width: max-content; }
.brand svg { width: 44px; fill: none; stroke: currentColor; stroke-width: 1.4; }
.brand > span { display: flex; flex-direction: column; gap: var(--space-1); font-size: var(--fs-body); font-weight: 600; letter-spacing: .25em; }
.brand small { font-size: var(--fs-micro); font-weight: 500; letter-spacing: .19em; opacity: .75; }
.main-nav { display: flex; align-items: center; gap: 40px; font-size: var(--fs-caption); }
.main-nav a { position: relative; opacity: .9; }
.main-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: -7px;
  height: 1px;
  background: currentColor;
  transition: right .3s var(--ease);
}
.main-nav a:hover { opacity: 1; }
.main-nav a:hover::after { right: 0; }
.round-button {
  justify-self: end;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--line);
  border-radius: 100px;
  background: rgba(237, 248, 247, .12);
  backdrop-filter: blur(10px);
  font-size: var(--fs-caption);
  transition: background .25s var(--ease), transform .25s var(--ease);
}
.round-button span { margin-left: var(--space-4); }
.round-button:hover { background: rgba(237, 248, 247, .2); transform: translateY(-2px); }

.hero {
  position: absolute;
  z-index: 3;
  top: 21.5%;
  left: 5.7vw;
  opacity: var(--hero-opacity);
  transform: translate3d(0, var(--hero-y), 0);
  filter: blur(var(--hero-blur));
  pointer-events: none;
}
.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 0 0 var(--space-5);
  font-size: var(--fs-micro);
  font-weight: 600;
  letter-spacing: .27em;
}
.eyebrow > span { width: 22px; height: 1px; background: currentColor; }
.hero h1 {
  margin: 0 0 var(--space-6);
  font-family: "Instrument Serif", Georgia, "Times New Roman", serif;
  font-size: clamp(76px, 8.4vw, 142px);
  font-weight: 400;
  line-height: .78;
  letter-spacing: -.045em;
}
.hero h1 em { font-weight: 400; }
.hero-description { margin: 0 0 12px; font-size: var(--fs-body); line-height: 1.9; letter-spacing: .08em; opacity: .8; }
.hero-quote {
  margin: 0 0 var(--space-7);
  color: #0a3140;
  font-family: "Noto Serif SC", "Songti SC", "STSong", serif;
  font-size: var(--fs-body);
  line-height: 2;
  letter-spacing: .1em;
  opacity: .92;
}
.hero-actions { display: flex; align-items: center; gap: var(--space-6); pointer-events: auto; }
.primary-button {
  min-width: 165px;
  padding: var(--space-4) var(--space-5);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  border: 1px solid transparent;
  border-radius: 100px;
  color: #eef9f6;
  background: #082c41;
  font-size: var(--fs-caption);
  box-shadow: 0 8px 30px rgba(0, 24, 39, .12);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease), background .3s var(--ease);
}
.is-underwater .primary-button { color: #073043; background: #d9f4ef; }
.primary-button:hover { transform: translateY(-3px); box-shadow: 0 12px 30px rgba(0, 24, 39, .25); }
.sound-button {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: 8px 0;
  border: 0;
  background: none;
  font-size: var(--fs-caption);
}
.sound-icon { height: 17px; display: flex; align-items: center; gap: 2px; }
.sound-icon i { display: block; width: 1px; height: 5px; background: currentColor; }
.sound-icon i:nth-child(2) { height: 12px; }
.sound-icon i:nth-child(3) { height: 17px; }
.sound-icon i:nth-child(4) { height: 8px; }
.sound-button[aria-pressed="true"] { color: var(--sand); }
.sound-button[aria-pressed="true"] .sound-icon i { animation: sound .8s ease-in-out infinite alternate; }
.sound-button[aria-pressed="true"] .sound-icon i:nth-child(2) { animation-delay: -.3s; }
.sound-button[aria-pressed="true"] .sound-icon i:nth-child(3) { animation-delay: -.6s; }
@keyframes sound { to { transform: scaleY(.3); } }

.dive-caption {
  position: absolute;
  z-index: 2;
  left: 50%;
  top: 50%;
  text-align: center;
  color: #effbf8;
  opacity: var(--dive-opacity);
  transform: translate(-50%, -50%);
  transition: opacity .7s ease;
  pointer-events: none;
}
.dive-caption span { font-size: var(--fs-micro); letter-spacing: .35em; }
.dive-caption p { margin: var(--space-4) 0; font-family: "Noto Serif SC", "Songti SC", serif; font-size: clamp(24px, 3vw, 44px); letter-spacing: .2em; }

.resource-world {
  position: absolute;
  z-index: 4;
  inset: 0;
  opacity: var(--resource-opacity);
  transform: translate3d(0, var(--resource-y), 0);
  /* ease-in-out 起步轻，避免标题"一秒出现"的断层感 */
  transition: opacity 1.2s cubic-bezier(.4, 0, .2, 1), transform 1.2s cubic-bezier(.4, 0, .2, 1);
  pointer-events: none;
  overflow-y: auto;
  scrollbar-width: none;
  scroll-behavior: smooth;
}
.resource-world::-webkit-scrollbar { display: none; }
.resource-world.is-active { pointer-events: auto; }
.deep-scroll {
  min-height: 100%;
  padding: 13vh 6.5vw 12vh;
  color: #eef9f6;
}
.deep-layer {
  min-height: 76vh;
  display: flex;
  flex-direction: column;
  scroll-margin-top: 14vh;
}
.about-layer { justify-content: center; }
.resource-heading { display: flex; align-items: flex-end; justify-content: space-between; }
.resource-heading .eyebrow { margin-bottom: 12px; color: #a5d8d3; }
.resource-heading h2, .layer-title {
  margin: 0;
  font-family: "Noto Serif SC", "Songti SC", "STSong", serif;
  font-size: clamp(32px, 3.5vw, 56px);
  font-weight: 400;
  letter-spacing: .08em;
}
.layer-title { margin-bottom: 4vh; }
.resource-heading > p { margin: 0; text-align: right; color: rgba(230, 248, 246, .72); font-size: var(--fs-caption); line-height: 1.8; letter-spacing: .08em; }
.resource-heading > p strong { margin-right: 4px; color: var(--sand); font-family: "Instrument Serif", Georgia, serif; font-size: 24px; font-weight: 400; }

.site-list { margin-top: 4.5vh; display: grid; grid-template-columns: repeat(6, 1fr); gap: var(--space-3); }
.site-card {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-4) var(--space-5);
  border: 1px solid rgba(211, 241, 236, .14);
  border-radius: 6px;
  background: linear-gradient(120deg, rgba(207, 239, 233, .08), rgba(8, 49, 61, .14));
  backdrop-filter: blur(14px);
  transition: transform .3s var(--ease), border-color .3s var(--ease);
}
/* 层级：两座博客各占 3 列作特辑，其余三枚资源站各占 2 列，破掉均分呆感 */
.site-card:nth-child(-n+2) { grid-column: span 3; padding: 22px var(--space-6); }
.site-card:nth-child(-n+2) .site-info h3 {
  font-family: "Instrument Serif", "Noto Serif SC", Georgia, serif;
  font-size: var(--fs-title);
  font-weight: 400;
  letter-spacing: .03em;
}
.site-card:nth-child(n+3) { grid-column: span 2; }
.site-card:hover { transform: translateY(-3px); border-color: rgba(211, 241, 236, .4); }
.site-card.accent { border-color: rgba(157, 229, 220, .35); background: linear-gradient(120deg, rgba(93, 202, 165, .12), rgba(8, 49, 61, .16)); }
/* 暖沙 accent：两张特调卡一冷一暖，形成节奏 */
.site-card.accent.warm { border-color: rgba(238, 194, 127, .38); background: linear-gradient(120deg, rgba(238, 194, 127, .1), rgba(8, 49, 61, .16)); }
.site-card.accent.warm .site-icon { border-color: rgba(238, 194, 127, .55); color: var(--sand); }
.site-card.accent.warm:hover { border-color: rgba(238, 194, 127, .6); }
.site-icon {
  width: 34px;
  height: 34px;
  flex: 0 0 auto;
  display: grid;
  place-items: center;
  border: 1px solid rgba(218, 245, 240, .2);
  border-radius: 50%;
  color: #c3e9e3;
  font-family: "Noto Serif SC", "Songti SC", "STSong", serif;
  font-size: 15px;
}
.site-card.accent .site-icon { border-color: rgba(157, 229, 220, .5); color: #9de5dc; }
.site-info { flex: 1; min-width: 0; }
.site-info h3 { margin: 0 0 4px; font-size: var(--fs-body); font-weight: 500; }
.site-info p { margin: 0; color: rgba(230, 247, 244, .68); font-size: var(--fs-caption); letter-spacing: .05em; }
.site-arrow { font-size: 14px; opacity: .6; transition: transform .3s var(--ease), opacity .3s var(--ease), color .3s var(--ease); }
.site-card:hover .site-arrow { opacity: 1; color: var(--sand); transform: translate(2px, -2px); }

.scroll-cue {
  margin-top: auto;
  padding-top: 6vh;
  text-align: center;
  color: rgba(230, 248, 246, .68);
  font-size: var(--fs-micro);
  letter-spacing: .25em;
  line-height: 2;
}
.scroll-cue span {
  display: inline-grid;
  place-items: center;
  width: 30px;
  height: 30px;
  margin-bottom: 6px;
  border: 1px solid rgba(222, 246, 243, .25);
  border-radius: 50%;
  font-size: 12px;
  animation: down 1.8s ease-in-out infinite;
}

.carousel { display: grid; grid-template-columns: auto 1fr auto; gap: var(--space-4); align-items: center; }
.car-arrow {
  width: 40px;
  height: 40px;
  border: 1px solid rgba(211, 241, 236, .2);
  border-radius: 50%;
  background: rgba(237, 248, 247, .05);
  color: #c3e9e3;
  font-size: 13px;
  transition: background .25s var(--ease), transform .25s var(--ease);
}
.car-arrow:hover { background: rgba(237, 248, 247, .15); transform: scale(1.06); }
.car-stage {
  border: 1px solid rgba(211, 241, 236, .14);
  border-radius: 8px;
  overflow: hidden;
  background: linear-gradient(120deg, rgba(207, 239, 233, .09), rgba(8, 49, 61, .16));
  backdrop-filter: blur(14px);
  animation: card-in .5s var(--ease) both;
}
/* 轮播滑动：轨道横移，0.5s 滚到下一张 */
.car-track { display: flex; transition: transform .5s var(--ease); }
.car-slide { width: 100%; flex-shrink: 0; }
@keyframes card-in { from { opacity: 0; transform: translateY(16px); } }
.car-visual {
  position: relative;
  height: clamp(300px, 40vh, 420px);
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(3, 28, 41, .42);
  border-bottom: 1px solid rgba(211, 241, 236, .1);
  overflow: hidden;
}
.car-visual img {
  display: block;
  max-width: 100%;
  max-height: 100%;
  width: auto;
  height: auto;
  object-fit: contain;
}
.car-visual svg { width: 76%; height: 82%; }
/* 查看原图按钮 */
.car-fullscreen {
  position: absolute;
  right: 12px;
  bottom: 12px;
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(211, 241, 236, .3);
  border-radius: 50%;
  background: rgba(3, 28, 41, .55);
  backdrop-filter: blur(8px);
  color: #c3e9e3;
  font-size: 16px;
  line-height: 1;
  cursor: pointer;
  opacity: 0;
  transform: translateY(6px);
  transition: opacity .25s var(--ease), transform .25s var(--ease), background .25s var(--ease);
}
.car-visual:hover .car-fullscreen { opacity: 1; transform: translateY(0); }
.car-fullscreen:hover { background: rgba(157, 229, 220, .25); color: #eef9f6; }
.car-body { padding: var(--space-5) var(--space-6); display: flex; justify-content: space-between; align-items: flex-end; gap: var(--space-5); }
.car-body h3 { margin: 0 0 var(--space-1); font-family: "Instrument Serif", Georgia, serif; font-size: var(--fs-title); font-weight: 400; letter-spacing: .02em; }
.car-body p { margin: 0; max-width: 460px; color: rgba(230, 247, 244, .72); font-size: var(--fs-caption); line-height: 1.8; }
/* 作品集三行结构化介绍：定位一行 + 亮点两条 */
.car-desc { color: rgba(237, 248, 247, .9) !important; font-weight: 500; }
.car-points { margin: var(--space-3) 0 0; padding: 0; list-style: none; display: grid; gap: var(--space-1); }
.car-points li {
  position: relative;
  padding-left: 16px;
  color: rgba(230, 247, 244, .68);
  font-size: var(--fs-caption);
  line-height: 1.7;
}
.car-points li::before {
  content: "";
  position: absolute;
  left: 2px;
  top: .62em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--aqua);
  opacity: .7;
}
.car-tags { margin-top: var(--space-3); display: flex; flex-wrap: wrap; gap: var(--space-2); }
.car-tags span { padding: var(--space-1) var(--space-3); border: 1px solid rgba(211, 241, 236, .18); border-radius: 100px; color: rgba(224, 246, 242, .75); font-size: var(--fs-micro); letter-spacing: .12em; }
.car-link {
  flex: 0 0 auto;
  padding: 10px 18px;
  border: 1px solid rgba(157, 229, 220, .4);
  border-radius: 100px;
  color: #9de5dc;
  font-size: var(--fs-caption);
  transition: background .25s var(--ease);
}
.car-link:hover { background: rgba(157, 229, 220, .12); }
.car-dots { margin-top: var(--space-4); display: flex; justify-content: center; gap: var(--space-2); }
.car-dots button { width: 6px; height: 6px; padding: 0; border: 0; border-radius: 50%; background: rgba(237, 248, 247, .25); transition: background .25s var(--ease), transform .25s var(--ease); }
.car-dots button.active { background: #9de5dc; transform: scale(1.3); }

.github-block { margin-top: 6vh; }
.github-block .eyebrow { color: #a5d8d3; }
.gh-list { margin-top: 2.2vh; display: flex; flex-direction: column; gap: 8px; }
.gh-row {
  display: flex;
  align-items: center;
  gap: var(--space-4);
  padding: var(--space-3) var(--space-4);
  border: 1px solid rgba(211, 241, 236, .12);
  border-radius: 6px;
  background: rgba(8, 49, 61, .2);
  transition: transform .3s var(--ease), border-color .3s var(--ease);
}
.gh-row:hover { transform: translateX(4px); border-color: rgba(211, 241, 236, .35); }
.gh-name { font-size: var(--fs-caption); font-weight: 500; }
.gh-desc { flex: 1; min-width: 0; color: rgba(230, 247, 244, .68); font-size: var(--fs-caption); }
.gh-stars { color: var(--sand); font-size: var(--fs-caption); }

.about-me { margin: auto; max-width: 560px; text-align: center; }
.about-avatar {
  width: 76px;
  height: 76px;
  margin: 0 auto var(--space-5);
  display: grid;
  place-items: center;
  border: 1px solid rgba(157, 229, 220, .5);
  border-radius: 50%;
  overflow: hidden;
  background: rgba(12, 68, 124, .35);
}
.about-avatar img { width: 100%; height: 100%; object-fit: cover; display: block; }
.about-name { margin: 0 0 var(--space-2); font-family: "Instrument Serif", Georgia, serif; font-size: 26px; }
.about-role { margin: 0 0 4vh; color: rgba(230, 247, 244, .7); font-size: var(--fs-caption); letter-spacing: .12em; }
.about-intro { margin: 0 auto 4.5vh; max-width: 430px; color: rgba(237, 248, 247, .88); font-size: var(--fs-body); line-height: 2.1; }
.contact-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-3); margin-bottom: 5vh; }
.contact-grid a { padding: var(--space-3) 0; border: 1px solid rgba(211, 241, 236, .16); border-radius: 6px; background: rgba(8, 49, 61, .2); font-size: var(--fs-caption); transition: border-color .25s var(--ease), color .25s var(--ease); }
.contact-grid a:hover { border-color: rgba(157, 229, 220, .5); color: #9de5dc; }
.about-quote { margin: 0 0 4vh; color: #c3e9e3; font-family: "Noto Serif SC", "Songti SC", "STSong", serif; font-size: 15px; letter-spacing: .12em; }
.surface-back {
  padding: var(--space-3) var(--space-6);
  border: 1px solid rgba(211, 241, 236, .35);
  border-radius: 100px;
  background: transparent;
  color: rgba(237, 248, 247, .9);
  font-size: var(--fs-caption);
  letter-spacing: .15em;
  transition: background .25s var(--ease);
}
.surface-back:hover { background: rgba(237, 248, 247, .12); }

.depth-meter {
  position: absolute;
  z-index: 3;
  right: 2.1vw;
  top: 44%;
  display: flex;
  flex-direction: column;
  align-items: center;
  color: var(--ink);
  opacity: .75;
}
.depth-label { margin-bottom: 12px; font-size: var(--fs-micro); letter-spacing: .22em; writing-mode: vertical-rl; }
.depth-track { position: relative; width: 1px; height: 76px; margin-bottom: 10px; background: var(--line); }
.depth-track i { position: absolute; top: 0; left: -1px; width: 3px; height: 100%; background: currentColor; transform: scaleY(0); transform-origin: top; }
.depth-meter strong { font-family: "Instrument Serif", Georgia, serif; font-size: 18px; font-weight: 400; }
.depth-meter small { font-size: var(--fs-micro); }
.ocean-footer {
  position: absolute;
  z-index: 6;
  left: 4.2vw;
  right: 4.2vw;
  bottom: 24px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  font-size: var(--fs-micro);
  letter-spacing: .2em;
  transition: opacity .5s var(--ease);
}
/* 下潜后隐藏页脚，避免盖住深海区内容 */
.is-underwater .ocean-footer { opacity: 0; pointer-events: none; }
.ocean-footer button { width: max-content; padding: 0; border: 0; background: none; font-size: inherit; letter-spacing: inherit; }
.pause-symbol { display: inline-grid; place-items: center; width: 22px; height: 22px; margin-right: 8px; border: 1px solid var(--line); border-radius: 50%; font-size: var(--fs-micro); }
.scroll-hint { justify-self: center; transition: opacity .4s var(--ease); }
.scroll-hint i { display: inline-block; margin-left: var(--space-3); font-size: 13px; font-style: normal; animation: down 1.8s ease-in-out infinite; }
@keyframes down { 50% { transform: translateY(5px); } }
.coordinate { justify-self: end; opacity: .7; }

.is-diving .ocean-video,
.motion-paused .ocean-video {
  animation: none;
}
.stage-diving .ocean-video {
  animation: none;
}

@media (max-width: 900px) {
  .main-nav { display: none; }
  .site-header { grid-template-columns: 1fr 1fr; }
  .hero { top: 24%; }
  .hero h1 { font-size: clamp(70px, 12vw, 110px); }
  .deep-scroll { padding-left: 5vw; padding-right: 5vw; }
  .site-list { grid-template-columns: 1fr; }
  .site-list .site-card:nth-child(n) { grid-column: auto; }
  .site-info p { display: none; }
  .car-body { flex-direction: column; align-items: flex-start; gap: 14px; }
  .contact-grid { grid-template-columns: repeat(2, 1fr); }
  .depth-meter { display: none; }
}
@media (max-width: 600px) {
  .ocean-journey { height: 100vh; height: 100svh; }
  .ocean-stage { min-height: 560px; }
  .announcement { justify-content: space-between; padding: 0 6vw; }
  .site-header { padding: 0 6vw; }
  .brand small { display: none; }
  .round-button { padding: 10px 13px; }
  .round-button span { margin-left: 8px; }
  .hero { top: 23%; left: 7vw; }
  .hero h1 { font-size: clamp(64px, 20vw, 90px); line-height: .84; }
  .hero-description { font-size: var(--fs-caption); }
  .hero-quote { font-size: var(--fs-caption); }
  .hero-actions { gap: 16px; }
  .primary-button { min-width: 145px; }
  .sound-button { font-size: var(--fs-caption); }
  .ocean-footer { left: 6vw; right: 6vw; grid-template-columns: 1fr 1fr; }
  .scroll-hint { justify-self: end; }
  .coordinate { display: none; }
  .deep-scroll { padding: 13vh 6vw 10vh; }
  .deep-layer { min-height: 82vh; }
  .resource-heading h2, .layer-title { font-size: 29px; }
  .resource-heading > p { display: none; }
  .site-card { padding: var(--space-3) var(--space-4); gap: var(--space-3); }
  .site-card:nth-child(-n+2) { padding: var(--space-3) var(--space-4); }
  .car-visual { height: clamp(200px, 30vh, 280px); }
  .car-visual img { max-height: 100%; }
  .car-arrow { width: 32px; height: 32px; }
  .carousel { gap: 8px; }
  .car-body { padding: var(--space-3) var(--space-4) var(--space-4); }
  .car-body h3 { font-size: 17px; }
  .gh-row { flex-wrap: wrap; gap: 8px; }
  .dive-caption { width: 100%; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    transition-delay: 0ms !important;
  }
  .ocean-grain { display: none; }
  .ocean-video { animation: none !important; }
  .scroll-hint i, .scroll-cue span { animation: none !important; }
}

/* 五岛气泡入场：JS（WAAPI）驱动，类名不复用背景微气泡的 .bubble */
.isle-bubble {
  position: fixed;
  width: 70px;
  height: 70px;
  margin: -35px 0 0 -35px;
  border-radius: 50%;
  border: 1.5px solid rgba(157, 229, 220, .6);
  background:
    radial-gradient(circle at 32% 26%, rgba(255,255,255,.30), rgba(157,229,220,.08) 45%, rgba(6,40,52,.16) 100%);
  box-shadow: inset 0 0 0 1px rgba(255,255,255,.10), 0 8px 26px rgba(0,0,0,.30);
  pointer-events: none;
  z-index: 30;
  opacity: 0;
  will-change: transform, opacity;
}
.isle-bubble::after {
  content: "";
  position: absolute;
  top: 16%;
  left: 24%;
  width: 30%;
  height: 18%;
  border-radius: 50%;
  background: rgba(255,255,255,.40);
  filter: blur(1px);
  transform: rotate(-24deg);
}
.isle-particle {
  position: fixed;
  border-radius: 50%;
  background: var(--aqua);
  pointer-events: none;
  z-index: 31;
  opacity: 0;
  will-change: transform, opacity;
}

/* 查看原图 —— 站内放大预览（lightbox） */
.lightbox {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 5vh 5vw;
  background: rgba(4, 22, 31, .92);
  backdrop-filter: blur(14px);
  opacity: 0;
  pointer-events: none;
  transition: opacity .35s var(--ease);
}
.lightbox.is-open {
  opacity: 1;
  pointer-events: auto;
}
.lightbox-figure {
  margin: 0;
  max-width: min(92vw, 1280px);
  max-height: 88vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-4);
  transform: scale(.96);
  transition: transform .35s var(--ease);
}
.lightbox.is-open .lightbox-figure { transform: scale(1); }
.lightbox-img {
  display: block;
  max-width: 100%;
  max-height: 78vh;
  width: auto;
  height: auto;
  border-radius: 10px;
  border: 1px solid rgba(211, 241, 236, .16);
  box-shadow: 0 24px 80px rgba(0, 0, 0, .5);
  object-fit: contain;
}
.lightbox-caption {
  display: flex;
  align-items: baseline;
  gap: var(--space-3);
  color: rgba(237, 248, 247, .85);
}
.lightbox-caption strong {
  font-family: "Instrument Serif", Georgia, serif;
  font-size: var(--fs-title);
  font-weight: 400;
  letter-spacing: .02em;
}
.lightbox-caption span {
  color: var(--sand);
  font-size: var(--fs-micro);
  letter-spacing: .18em;
}
.lightbox-close {
  position: absolute;
  top: 20px;
  right: 22px;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border: 1px solid rgba(211, 241, 236, .3);
  border-radius: 50%;
  background: rgba(3, 28, 41, .5);
  color: #eef9f6;
  font-size: 24px;
  line-height: 1;
  cursor: pointer;
  transition: background .25s var(--ease), transform .25s var(--ease);
}
.lightbox-close:hover { background: rgba(157, 229, 220, .25); transform: rotate(90deg); }
@media (max-width: 720px) {
  .lightbox { padding: 4vh 4vw; }
  .lightbox-close { top: 12px; right: 12px; width: 38px; height: 38px; }
}