/* 远洋 — 深海主题 404 · 深青蓝海水 + 荧光青 */

:root{
  --deep:#03151f;
  --sea:#04202e;
  --sea2:#06334a;
  --ink:#e8f6f4;
  --muted:rgba(232,246,244,.62);
  --line:rgba(232,246,244,.14);
  --accent:#35e0c0;
  --accent-soft:rgba(53,224,192,.12);
  --ease:cubic-bezier(.22,.61,.36,1);
}

*{box-sizing:border-box}

html,body{margin:0;padding:0}

body{
  min-height:100vh;
  background:var(--deep);
  color:var(--ink);
  font-family:"PingFang SC","Hiragino Sans GB","Microsoft YaHei",system-ui,sans-serif;
  font-size:15px;
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}

/* ---------- 海水 ---------- */

.sea{
  position:fixed;
  inset:0;
  z-index:0;
  background:linear-gradient(180deg,#022430 0%, var(--sea2) 34%, var(--sea) 62%, var(--deep) 100%);
}

/* 水面透光：几道缓慢摆动的光柱 */
.beams{
  position:fixed;
  inset:0 0 auto 0;
  height:70vh;
  z-index:1;
  pointer-events:none;
  overflow:hidden;
}

.beam{
  position:absolute;
  top:-16vh;
  width:14vw;
  height:88vh;
  background:linear-gradient(180deg, rgba(53,224,192,.14) 0%, rgba(53,224,192,.04) 46%, transparent 100%);
  transform-origin:top center;
  filter:blur(6px);
  animation:sway 13s var(--ease) infinite;
}

@keyframes sway{
  0%,100%{transform:rotate(-7deg) scaleY(1)}
  50%{transform:rotate(6deg) scaleY(1.06)}
}

.beam:nth-child(1){left:9%;animation-delay:0s}
.beam:nth-child(2){left:31%;width:9vw;animation-delay:-3.5s}
.beam:nth-child(3){left:54%;width:17vw;animation-delay:-6s}
.beam:nth-child(4){left:76%;width:11vw;animation-delay:-9s}

/* 气泡 */
.bubbles{
  position:fixed;
  inset:0;
  z-index:1;
  pointer-events:none;
}

.bub{
  position:absolute;
  bottom:-40px;
  border-radius:50%;
  border:1px solid rgba(232,246,244,.22);
  background:rgba(232,246,244,.05);
  animation:rise 14s linear infinite;
}

@keyframes rise{
  0%{transform:translateY(0) translateX(0);opacity:0}
  8%{opacity:.75}
  92%{opacity:.5}
  100%{transform:translateY(-112vh) translateX(26px);opacity:0}
}

/* 海面：三层波浪横向漂移 + 航标灯。
   放弃了写实鲸鱼——抽象海洋生物在小尺寸下容易糊成色块，
   波浪和航标反而明确，也更贴「远洋 / 航线」这个品牌。 */
.floor{
  position:fixed;
  left:0;right:0;bottom:0;
  height:36vh;
  z-index:1;
  pointer-events:none;
}

.wave{
  position:absolute;
  left:0;bottom:0;
  width:200%;
  height:100%;
}

.wave svg{display:block;width:100%;height:100%}

.wave path{fill:#06587a}

.w1{animation:drift 20s linear infinite}
.w2{bottom:17%;opacity:.72;animation:drift 30s linear infinite reverse}
.w2 path{fill:#044a66}
.w3{bottom:34%;opacity:.5;animation:drift 42s linear infinite}
.w3 path{fill:#053a52}

@keyframes drift{
  from{transform:translateX(0)}
  to{transform:translateX(-50%)}
}

/* 航标灯：页脚精简后底部空出来了，回到居中 */
.buoy{
  position:absolute;
  left:50%;bottom:24%;
  width:56px;height:92px;
  margin-left:-28px;
  animation:bob 6s var(--ease) infinite;
}

.buoy svg{display:block;width:100%;height:100%}

.lamp{
  position:absolute;
  left:50%;top:-7px;
  width:17px;height:17px;
  margin-left:-8.5px;
  border-radius:50%;
  background:var(--accent);
  animation:glow 3.2s var(--ease) infinite;
}

@keyframes bob{
  0%,100%{transform:translateY(0) rotate(-2deg)}
  50%{transform:translateY(-10px) rotate(2deg)}
}

@keyframes glow{
  0%,100%{box-shadow:0 0 18px 5px rgba(53,224,192,.30)}
  50%{box-shadow:0 0 34px 12px rgba(53,224,192,.62)}
}

/* ---------- 导航 ---------- */

.nav{
  position:relative;
  z-index:3;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:20px;
  max-width:1060px;
  margin:0 auto;
  padding:22px 26px;
}

.brand{
  display:inline-flex;
  align-items:center;
  gap:9px;
  font-size:16.5px;
  font-weight:500;
  color:var(--ink);
  text-decoration:none;
  letter-spacing:.04em;
}

.brand .wave{
  width:22px;height:12px;
  flex:none;
  background:
    radial-gradient(circle at 25% 100%, var(--accent) 0 3px, transparent 3.5px),
    radial-gradient(circle at 75% 100%, var(--accent) 0 3px, transparent 3.5px);
  border-bottom:1.6px solid var(--accent);
  border-radius:0 0 11px 11px;
}

.nav ul{
  display:flex;
  gap:24px;
  margin:0;padding:0;
  list-style:none;
  font-size:13.5px;
}

.nav ul a{color:var(--muted);text-decoration:none;transition:color .2s var(--ease)}
.nav ul a:hover{color:var(--ink)}
.nav ul a.on{color:var(--accent)}

a:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:3px}

.nav .mini{
  padding:7px 16px;
  font-size:13px;
  color:var(--accent);
  border:1px solid var(--accent);
  border-radius:999px;
  text-decoration:none;
  transition:background .22s var(--ease), color .22s var(--ease);
}

.nav .mini:hover{background:var(--accent);color:var(--deep)}

/* ---------- 404 主体 ---------- */

.stage{
  position:relative;
  z-index:2;
  max-width:1060px;
  margin:0 auto;
  padding:6vh 26px 0;
  text-align:center;
}

.stage h1{
  max-width:22ch;
  margin:0 auto 10px;
  font-size:clamp(22px,2.8vw,31px);
  font-weight:500;
  line-height:1.44;
}

.stage .sub{
  max-width:40ch;
  margin:0 auto;
  font-size:14.5px;
  color:var(--muted);
}

/* 巨型数字：悬在鲸脊上方 */
.big{
  margin:2vh 0 0;
  font-size:clamp(120px,26vw,300px);
  font-weight:500;
  line-height:.86;
  letter-spacing:-.04em;
  color:var(--ink);
  text-shadow:0 0 80px rgba(53,224,192,.22);
  animation:bob 7s var(--ease) infinite;
}

@keyframes bob{
  0%,100%{transform:translateY(0)}
  50%{transform:translateY(-16px)}
}

.back{
  display:inline-block;
  margin-top:1vh;
  padding:12px 28px;
  font-size:14px;
  color:var(--ink);
  background:rgba(232,246,244,.07);
  border:1px solid var(--line);
  border-radius:999px;
  text-decoration:none;
  backdrop-filter:blur(8px);
  -webkit-backdrop-filter:blur(8px);
  transition:background .22s var(--ease), border-color .22s var(--ease), transform .22s var(--ease);
}

.back:hover{
  background:var(--accent-soft);
  border-color:var(--accent);
  transform:translateY(-2px);
}

.back:focus-visible{outline:2px solid var(--accent);outline-offset:3px}

/* 页脚叠在鲸之上 */
/* 404 页只留一行页脚：原来的五列链接块会占满底部，
   把 fixed 的波浪和航标整个盖住。一行足够，也不抢视觉。 */
.foot-simple{
  position:relative;
  z-index:3;
  max-width:1060px;
  margin:7vh auto 3vh;
  padding:14px 26px 0;
  display:flex;
  justify-content:space-between;
  gap:14px;
  flex-wrap:wrap;
  border-top:1px solid var(--line);
  font-size:12.5px;
  color:var(--muted);
}

.foot-simple a{text-decoration:none}
.foot-simple a:hover{color:var(--accent)}

.foot h3{
  margin:0 0 10px;
  font-size:11.5px;
  font-weight:500;
  letter-spacing:.14em;
  color:var(--accent);
}

.foot ul{margin:0;padding:0;list-style:none}
.foot li{margin-bottom:6px}
.foot a{color:var(--muted)}
.foot a:hover{color:var(--ink)}

.sub-form{
  display:flex;
  gap:6px;
  margin-top:8px;
}

.sub-form input{
  flex:1;
  min-width:0;
  padding:8px 11px;
  font:inherit;
  font-size:12.5px;
  color:var(--ink);
  background:rgba(232,246,244,.06);
  border:1px solid var(--line);
  border-radius:8px;
  outline:none;
  transition:border-color .2s var(--ease);
}

.sub-form input:focus{border-color:var(--accent)}
.sub-form input:focus-visible{outline:2px solid var(--accent);outline-offset:1px}

.sub-form button{
  padding:8px 13px;
  font:inherit;
  font-size:12.5px;
  color:var(--deep);
  background:var(--accent);
  border:none;
  border-radius:8px;
  cursor:pointer;
  transition:opacity .2s var(--ease);
}

.sub-form button:hover{opacity:.86}
.sub-form button:focus-visible{outline:2px solid var(--ink);outline-offset:2px}

/* ---------- 内页 ---------- */

.page{
  position:relative;
  z-index:2;
  max-width:860px;
  margin:0 auto;
  padding:52px 26px 100px;
}

.eyebrow{
  display:inline-block;
  margin-bottom:16px;
  padding:5px 13px;
  font-size:11.5px;
  letter-spacing:.16em;
  color:var(--accent);
  border:1px solid var(--accent);
  border-radius:999px;
}

.page h2{
  margin:0 0 16px;
  font-size:clamp(26px,4vw,40px);
  font-weight:500;
  line-height:1.36;
}

.page p.lede{
  max-width:46ch;
  margin:0 0 28px;
  font-size:15.5px;
  color:var(--muted);
}

.grid{
  display:grid;
  grid-template-columns:repeat(2,minmax(0,1fr));
  gap:16px;
  margin-top:36px;
}

.cell{
  padding:24px 22px;
  border:1px solid var(--line);
  border-radius:16px;
  background:rgba(232,246,244,.035);
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  transition:border-color .3s var(--ease), transform .3s var(--ease);
}

.cell:hover{border-color:var(--accent);transform:translateY(-3px)}

.cell h3{margin:0 0 8px;font-size:17px;font-weight:500}
.cell p{margin:0;font-size:13.5px;color:var(--muted);line-height:1.72}
.cell .num{
  display:block;
  margin-bottom:12px;
  font-size:12px;
  letter-spacing:.14em;
  color:var(--accent);
  opacity:.85;
}

.cta{
  display:inline-block;
  margin-top:32px;
  padding:12px 26px;
  font-size:14px;
  color:var(--deep);
  background:var(--accent);
  border-radius:999px;
  text-decoration:none;
  transition:transform .2s var(--ease), box-shadow .25s var(--ease);
}

.cta:hover{transform:translateY(-2px);box-shadow:0 10px 26px rgba(53,224,192,.24)}
.cta:focus-visible{outline:2px solid var(--ink);outline-offset:3px}

@media (max-width:720px){
  .grid{grid-template-columns:minmax(0,1fr)}
  .nav ul{display:none}
  .nav{padding:16px 18px}
  .stage{padding:4vh 18px 0}
  .page{padding:32px 18px 80px}
  .floor{height:22vh}
  .buoy{width:40px;height:66px;margin-left:-20px}
}

@media (prefers-reduced-motion:reduce){
  *{animation-duration:.01ms !important;animation-iteration-count:1 !important;transition-duration:.01ms !important}
}