/* ============================================================
   云际竞技社 · 社团官网
   品牌色取自社徽实际像素：#0070C0 蓝 / #C03000 橙红
   ============================================================ */

:root{
  --blue:#0070C0;
  --blue-lt:#3FA9F5;
  --blue-dk:#004E8C;
  --flame:#C03000;
  --flame-lt:#FF6B35;

  --ink:#05080F;
  --ink-2:#0A1120;
  --ink-3:#0E1730;
  --line:rgba(120,170,230,.16);
  --line-2:rgba(120,170,230,.30);

  --tx:#E8F0FA;
  --tx-2:#9FB4CD;
  --tx-3:#6B82A0;

  --radius:16px;
  --wrap:1180px;
  --ease:cubic-bezier(.215,.61,.355,1);
  --ease-out:cubic-bezier(.23,1,.32,1);
}

*,*::before,*::after{box-sizing:border-box}

html{scroll-behavior:smooth}

body{
  margin:0;
  background:var(--ink);
  color:var(--tx);
  font:16px/1.7 "PingFang SC","Microsoft YaHei","Noto Sans SC",-apple-system,"Segoe UI",sans-serif;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}

img{max-width:100%;display:block}
/* 作者样式 img{display:block} 会覆盖 UA 的 [hidden]，这里显式补回 */
[hidden]{display:none !important}
a{color:inherit;text-decoration:none}
h1,h2,h3,h4{line-height:1.2;margin:0}
p{margin:0}

.wrap{width:100%;max-width:var(--wrap);margin-inline:auto;padding-inline:24px}

.skip{
  position:absolute;left:-9999px;top:0;z-index:999;
  background:var(--blue);color:#fff;padding:12px 20px;border-radius:0 0 10px 0;
}
.skip:focus{left:0}

/* ============================================================
   背景层（3D canvas + 极光 + 网格）
   ============================================================ */
#sky{
  position:fixed;inset:0;z-index:0;
  width:100%;height:100%;
  display:block;
}

.aurora{
  position:fixed;inset:-20% -10%;z-index:0;pointer-events:none;
  background:
    radial-gradient(46% 38% at 18% 22%, rgba(0,112,192,.32), transparent 62%),
    radial-gradient(40% 34% at 82% 18%, rgba(192,48,0,.18), transparent 64%),
    radial-gradient(52% 44% at 60% 86%, rgba(0,78,140,.28), transparent 68%);
  filter:blur(28px);
  animation:drift 26s var(--ease) infinite alternate;
}
@keyframes drift{
  0%{transform:translate3d(0,0,0) scale(1)}
  50%{transform:translate3d(-2.5%,1.8%,0) scale(1.06)}
  100%{transform:translate3d(2%,-1.4%,0) scale(1.03)}
}

.grid-plane{
  position:fixed;left:-25%;right:-25%;bottom:-12%;height:62vh;z-index:0;
  pointer-events:none;
  background-image:
    linear-gradient(rgba(0,112,192,.20) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0,112,192,.20) 1px, transparent 1px);
  background-size:64px 64px;
  transform:perspective(520px) rotateX(66deg);
  transform-origin:bottom center;
  mask-image:linear-gradient(to top, #000 6%, transparent 82%);
  -webkit-mask-image:linear-gradient(to top, #000 6%, transparent 82%);
  animation:scrollGrid 9s linear infinite;
}
@keyframes scrollGrid{to{background-position:0 64px, 64px 0}}

.vignette{
  position:fixed;inset:0;z-index:0;pointer-events:none;
  background:radial-gradient(120% 90% at 50% 40%, transparent 42%, rgba(5,8,15,.86) 100%);
}

.nav,.hero,.section,.foot{position:relative;z-index:2}

/* ============================================================
   导航
   ============================================================ */
.nav{
  position:fixed;top:0;left:0;right:0;z-index:50;
  transition:background .35s var(--ease), backdrop-filter .35s, border-color .35s;
  border-bottom:1px solid transparent;
}
.nav.is-stuck{
  background:rgba(5,8,15,.78);
  backdrop-filter:blur(14px) saturate(140%);
  -webkit-backdrop-filter:blur(14px) saturate(140%);
  border-bottom-color:var(--line);
}

.nav__inner{
  max-width:var(--wrap);margin-inline:auto;padding:14px 24px;
  display:flex;align-items:center;justify-content:space-between;gap:20px;
}

.brand{display:flex;align-items:center;gap:12px;min-width:0}
.brand__mark{
  width:46px;height:auto;object-fit:contain;flex:none;
  filter:drop-shadow(0 0 14px rgba(0,112,192,.55));
  transition:transform .4s var(--ease-out);
}
.brand:hover .brand__mark{transform:rotate(-6deg) scale(1.06)}
.brand__text{display:flex;flex-direction:column;line-height:1.25;min-width:0}
.brand__text strong{font-size:17px;letter-spacing:.5px}
.brand__text small{font-size:11px;color:var(--tx-3);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}

.nav__links{display:flex;align-items:center;gap:6px}
.nav__links a{
  position:relative;padding:9px 14px;border-radius:9px;
  font-size:14.5px;color:var(--tx-2);
  transition:color .25s, background .25s;
}
.nav__links a:hover{color:var(--tx);background:rgba(0,112,192,.12)}
.nav__links a::after{
  content:"";position:absolute;left:14px;right:14px;bottom:4px;height:1.5px;
  background:linear-gradient(90deg,var(--blue-lt),var(--flame-lt));
  transform:scaleX(0);transform-origin:left;
  transition:transform .3s var(--ease-out);
}
.nav__links a:hover::after{transform:scaleX(1)}

.nav__cta{
  background:linear-gradient(135deg,var(--blue),var(--blue-dk)) !important;
  color:#fff !important;font-weight:600;
  box-shadow:0 6px 20px rgba(0,112,192,.36);
}
.nav__cta::after{display:none}
.nav__cta:hover{box-shadow:0 8px 26px rgba(0,112,192,.55);transform:translateY(-1px)}

.nav__toggle{
  display:none;flex-direction:column;gap:5px;
  background:none;border:0;padding:10px;cursor:pointer;
}
.nav__toggle span{
  width:24px;height:2px;background:var(--tx);border-radius:2px;
  transition:transform .3s var(--ease), opacity .3s;
}
.nav__toggle[aria-expanded="true"] span:nth-child(1){transform:translateY(7px) rotate(45deg)}
.nav__toggle[aria-expanded="true"] span:nth-child(2){opacity:0}
.nav__toggle[aria-expanded="true"] span:nth-child(3){transform:translateY(-7px) rotate(-45deg)}

/* ============================================================
   首屏
   ============================================================ */
.hero{
  min-height:100svh;
  display:flex;align-items:center;
  padding:120px 0 90px;
  position:relative;
}
.hero__glow{
  position:absolute;inset:0;pointer-events:none;
  background:radial-gradient(58% 44% at 72% 46%, rgba(0,112,192,.18), transparent 70%);
}
.hero__wrap{
  display:grid;grid-template-columns:1.15fr .85fr;
  gap:60px;align-items:center;
}

.eyebrow{
  display:inline-flex;align-items:center;gap:9px;
  font-size:13px;letter-spacing:2.4px;text-transform:uppercase;
  color:var(--blue-lt);font-weight:600;margin-bottom:20px;
}
.dot{
  width:7px;height:7px;border-radius:50%;background:var(--flame-lt);
  box-shadow:0 0 0 0 rgba(255,107,53,.7);
  animation:pulse 2.2s infinite;
}
@keyframes pulse{
  0%{box-shadow:0 0 0 0 rgba(255,107,53,.65)}
  70%{box-shadow:0 0 0 11px rgba(255,107,53,0)}
  100%{box-shadow:0 0 0 0 rgba(255,107,53,0)}
}

.hero__title{
  font-size:clamp(2.7rem,7vw,5.1rem);
  font-weight:800;letter-spacing:2px;line-height:1.06;
  margin-bottom:26px;
}
.hero__title .line{display:block}
.hero__title em{
  font-style:normal;
  background:linear-gradient(120deg,var(--blue-lt),#8FD4FF 45%,var(--blue));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
.hero__title em.alt{
  background:linear-gradient(120deg,var(--flame-lt),#FFA36B 45%,var(--flame));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}

.hero__desc{max-width:56ch;color:var(--tx-2);font-size:16.5px;margin-bottom:34px}
.hero__desc strong{color:var(--tx);font-weight:600}

.hero__actions{display:flex;flex-wrap:wrap;gap:14px;margin-bottom:46px}

.btn{
  display:inline-flex;align-items:center;gap:9px;
  padding:13px 26px;border-radius:11px;
  font-size:15px;font-weight:600;cursor:pointer;
  border:1px solid transparent;
  transition:transform .28s var(--ease-out), box-shadow .28s, background .28s, border-color .28s;
}
.btn svg{width:17px;height:17px;fill:none;stroke:currentColor;stroke-width:2.1;stroke-linecap:round;stroke-linejoin:round}
.btn--primary{
  background:linear-gradient(135deg,var(--blue),var(--blue-dk));
  color:#fff;box-shadow:0 10px 30px rgba(0,112,192,.40);
}
.btn--primary:hover{transform:translateY(-3px);box-shadow:0 16px 40px rgba(0,112,192,.60)}
.btn--primary svg{transition:transform .3s var(--ease-out)}
.btn--primary:hover svg{transform:translateX(4px)}
.btn--ghost{
  border-color:var(--line-2);color:var(--tx);
  background:rgba(255,255,255,.03);
}
.btn--ghost:hover{border-color:var(--blue-lt);background:rgba(0,112,192,.14);transform:translateY(-3px)}

.stats{
  list-style:none;margin:0;padding:22px 0 0;
  display:grid;grid-template-columns:repeat(3,1fr);gap:18px;
  border-top:1px solid var(--line);
}
.stats li{display:flex;flex-direction:column;gap:2px}
.stats b{
  font-size:clamp(1.5rem,2.6vw,2.1rem);font-weight:800;
  background:linear-gradient(135deg,#fff,var(--blue-lt));
  -webkit-background-clip:text;background-clip:text;color:transparent;
  font-variant-numeric:tabular-nums;
}
.stats span{font-size:12.5px;color:var(--tx-3);line-height:1.4}

/* ============================================================
   3D 社徽舞台
   ============================================================ */
.hero__art{display:flex;flex-direction:column;align-items:center;gap:20px}

.stage3d{
  width:min(380px,80vw);aspect-ratio:1;
  perspective:1100px;
  perspective-origin:50% 50%;
}
.stage3d__inner{
  position:relative;width:100%;height:100%;
  transform-style:preserve-3d;
  display:grid;place-items:center;
  animation:stageFloat 7s ease-in-out infinite;
}
@keyframes stageFloat{
  0%,100%{transform:translateY(0) rotateX(0deg)}
  50%{transform:translateY(-12px) rotateX(3deg)}
}

.stage3d__glow{
  position:absolute;inset:12%;border-radius:50%;
  background:radial-gradient(circle, rgba(0,112,192,.42), rgba(0,112,192,0) 68%);
  filter:blur(20px);
  animation:glowPulse 4.4s ease-in-out infinite;
}
@keyframes glowPulse{
  0%,100%{transform:scale(1);opacity:.75}
  50%{transform:scale(1.14);opacity:1}
}

.stage3d__logo{
  position:relative;z-index:4;
  width:66%;height:auto;object-fit:contain;
  transform:translateZ(60px);
  filter:drop-shadow(0 22px 48px rgba(0,112,192,.55));
}

/* 三条 3D 轨道环
   结构：.orbit 负责静态倾斜，内层 i 负责自转，
   两者分离，倾斜角不会被动画覆盖 */
.orbit{
  position:absolute;inset:0;
  transform-style:preserve-3d;
  border-radius:50%;
}
.orbit i{
  position:absolute;inset:0;border-radius:50%;
  border:1.4px solid rgba(63,169,245,.34);
  transform-style:preserve-3d;
}

.orbit--1{transform:rotateX(74deg)}
.orbit--1 i{inset:4%;animation:spinZ 22s linear infinite}

.orbit--2{transform:rotateX(66deg) rotateY(22deg)}
.orbit--2 i{inset:16%;border-color:rgba(255,107,53,.34);animation:spinZ 16s linear infinite reverse}

.orbit--3{transform:rotateX(80deg) rotateY(-18deg)}
.orbit--3 i{inset:27%;border-style:dashed;border-color:rgba(63,169,245,.26);animation:spinZ 30s linear infinite}

@keyframes spinZ{
  from{transform:rotateZ(0deg)}
  to{transform:rotateZ(360deg)}
}

/* 轨道上的发光点 */
.orbit i::after{
  content:"";position:absolute;top:-3px;left:50%;
  width:6px;height:6px;border-radius:50%;
  background:var(--blue-lt);
  box-shadow:0 0 14px 3px rgba(63,169,245,.85);
}
.orbit--2 i::after{background:var(--flame-lt);box-shadow:0 0 14px 3px rgba(255,107,53,.85)}

.stage3d__scan{
  position:absolute;left:10%;right:10%;height:2px;z-index:5;
  background:linear-gradient(90deg,transparent,var(--blue-lt),transparent);
  box-shadow:0 0 16px 3px rgba(63,169,245,.7);
  animation:scan 4.2s var(--ease) infinite;
  opacity:.8;
  transform:translateZ(70px);
}
@keyframes scan{
  0%{top:14%;opacity:0}
  12%{opacity:.9}
  88%{opacity:.9}
  100%{top:86%;opacity:0}
}

.hero__artnote{font-size:12.5px;color:var(--tx-3);letter-spacing:1.2px}

.scrollhint{
  position:absolute;left:50%;bottom:34px;transform:translateX(-50%);
  width:26px;height:44px;border:1.6px solid var(--line-2);border-radius:14px;
  display:grid;place-items:start center;padding-top:8px;
}
.scrollhint span{
  width:3px;height:8px;border-radius:2px;background:var(--blue-lt);
  animation:wheel 1.9s ease-in-out infinite;
}
@keyframes wheel{
  0%{transform:translateY(0);opacity:0}
  35%{opacity:1}
  100%{transform:translateY(17px);opacity:0}
}

/* ============================================================
   通用区块
   ============================================================ */
.section{padding:110px 0}
.section--tint{
  background:linear-gradient(180deg,transparent,rgba(10,17,32,.72) 14%,rgba(10,17,32,.72) 86%,transparent);
}

.shead{max-width:760px;margin-bottom:56px}
.shead h2{font-size:clamp(1.85rem,3.9vw,2.9rem);font-weight:800;letter-spacing:1px;margin-bottom:16px}
.shead__lead{color:var(--tx-2);font-size:16.5px}
.shead__lead strong{color:var(--tx)}

/* 卡片（带 3D 倾斜） */
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(255px,1fr));gap:20px}
.card{
  position:relative;padding:30px 26px 28px;
  border:1px solid var(--line);border-radius:var(--radius);
  background:linear-gradient(160deg,rgba(14,23,48,.86),rgba(8,13,26,.72));
  overflow:hidden;
  transform-style:preserve-3d;
  will-change:transform;
  transition:transform .35s var(--ease-out), border-color .35s, box-shadow .35s;
}
.card::before{
  content:"";position:absolute;inset:0;border-radius:var(--radius);
  background:radial-gradient(70% 60% at 50% 0%, rgba(0,112,192,.20), transparent 70%);
  opacity:0;transition:opacity .35s;
}
.card:hover{border-color:var(--line-2);box-shadow:0 22px 50px rgba(0,0,0,.5)}
.card:hover::before{opacity:1}
.card>*{position:relative;z-index:1;transform:translateZ(24px)}

.card__ico{
  width:46px;height:46px;border-radius:12px;margin-bottom:18px;
  background:linear-gradient(135deg,rgba(0,112,192,.30),rgba(192,48,0,.20));
  border:1px solid var(--line-2);
  display:grid;place-items:center;
}
.card__ico::after{
  content:"";width:19px;height:19px;background:var(--blue-lt);
  -webkit-mask-repeat:no-repeat;mask-repeat:no-repeat;
  -webkit-mask-position:center;mask-position:center;
  -webkit-mask-size:contain;mask-size:contain;
}
.card__ico[data-ico="target"]::after{
  -webkit-mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Ccircle cx='12' cy='12' r='9'/%3E%3Ccircle cx='12' cy='12' r='4'/%3E%3C/svg%3E");
  mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Ccircle cx='12' cy='12' r='9'/%3E%3Ccircle cx='12' cy='12' r='4'/%3E%3C/svg%3E");
}
.card__ico[data-ico="users"]::after{
  -webkit-mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Cpath d='M16 20v-2a4 4 0 0 0-4-4H6a4 4 0 0 0-4 4v2'/%3E%3Ccircle cx='9' cy='7' r='4'/%3E%3Cpath d='M22 20v-2a4 4 0 0 0-3-3.9'/%3E%3C/svg%3E");
  mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Cpath d='M16 20v-2a4 4 0 0 0-4-4H6a4 4 0 0 0-4 4v2'/%3E%3Ccircle cx='9' cy='7' r='4'/%3E%3Cpath d='M22 20v-2a4 4 0 0 0-3-3.9'/%3E%3C/svg%3E");
}
.card__ico[data-ico="chip"]::after{
  -webkit-mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Crect x='6' y='6' width='12' height='12' rx='2'/%3E%3Cpath d='M9 2v3M15 2v3M9 19v3M15 19v3M2 9h3M2 15h3M19 9h3M19 15h3'/%3E%3C/svg%3E");
  mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Crect x='6' y='6' width='12' height='12' rx='2'/%3E%3Cpath d='M9 2v3M15 2v3M9 19v3M15 19v3M2 9h3M2 15h3M19 9h3M19 15h3'/%3E%3C/svg%3E");
}
.card__ico[data-ico="trophy"]::after{
  -webkit-mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Cpath d='M8 21h8M12 17v4M7 4h10v5a5 5 0 0 1-10 0z'/%3E%3Cpath d='M17 5h2a2 2 0 0 1 0 4h-2M7 5H5a2 2 0 0 0 0 4h2'/%3E%3C/svg%3E");
  mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2'%3E%3Cpath d='M8 21h8M12 17v4M7 4h10v5a5 5 0 0 1-10 0z'/%3E%3Cpath d='M17 5h2a2 2 0 0 1 0 4h-2M7 5H5a2 2 0 0 0 0 4h2'/%3E%3C/svg%3E");
}

.card h3{font-size:18px;margin-bottom:10px}
.card p{color:var(--tx-2);font-size:14.5px}

/* 备战赛项 */
.arena{display:grid;grid-template-columns:repeat(auto-fit,minmax(300px,1fr));gap:20px}
.arena__item{
  position:relative;padding:26px 24px;
  border:1px solid var(--line);border-radius:var(--radius);
  background:linear-gradient(155deg,rgba(14,23,48,.80),rgba(7,11,22,.66));
  transform-style:preserve-3d;
  will-change:transform;
  transition:transform .35s var(--ease-out), border-color .35s, box-shadow .35s;
}
.arena__item::after{
  content:"";position:absolute;left:24px;right:24px;top:0;height:2px;
  background:linear-gradient(90deg,var(--blue),var(--flame-lt));
  transform:scaleX(0);transform-origin:left;
  transition:transform .45s var(--ease-out);
}
.arena__item:hover{border-color:var(--line-2);box-shadow:0 20px 46px rgba(0,0,0,.48)}
.arena__item:hover::after{transform:scaleX(1)}
.arena__item>*{position:relative;z-index:1;transform:translateZ(18px)}

.arena__tag{
  display:inline-block;font-size:11.5px;font-weight:700;letter-spacing:1px;
  padding:4px 11px;border-radius:20px;margin-bottom:14px;
  border:1px solid rgba(0,112,192,.45);
  background:rgba(0,112,192,.16);color:var(--blue-lt);
}
.arena__item h3{font-size:17px;margin-bottom:7px}
.arena__sub{font-size:13px;color:var(--flame-lt);font-weight:600;margin-bottom:10px}
.arena__item p:last-child{color:var(--tx-2);font-size:14.5px}

/* 技术方向 */
.tracks{display:grid;gap:16px}
.track{
  display:grid;grid-template-columns:70px minmax(180px,260px) 1fr;gap:24px;
  align-items:center;
  padding:22px 26px;border:1px solid var(--line);border-radius:var(--radius);
  background:linear-gradient(120deg,rgba(14,23,48,.72),rgba(8,13,26,.5));
  transform-style:preserve-3d;
  will-change:transform;
  transition:border-color .3s, transform .3s var(--ease-out), background .3s;
}
.track:hover{border-color:var(--line-2);background:linear-gradient(120deg,rgba(0,112,192,.16),rgba(8,13,26,.5))}
.track>*{position:relative;z-index:1;transform:translateZ(16px)}
.track__no{
  font-size:26px;font-weight:800;font-variant-numeric:tabular-nums;
  background:linear-gradient(135deg,var(--blue-lt),var(--blue));
  -webkit-background-clip:text;background-clip:text;color:transparent;
}
.track h3{font-size:17px}
.track p{color:var(--tx-2);font-size:14px}
.bar{height:5px;border-radius:4px;background:rgba(120,170,230,.14);overflow:hidden}
.bar i{
  display:block;height:100%;width:0;border-radius:4px;
  background:linear-gradient(90deg,var(--blue),var(--flame-lt));
  transition:width 1.2s var(--ease-out);
}
.track.is-in .bar i{width:var(--w)}

/* ============================================================
   加入 + 公众号
   ============================================================ */
.join__wrap{display:grid;grid-template-columns:1.15fr .85fr;gap:48px;align-items:start}
.join h2{font-size:clamp(1.85rem,3.9vw,2.9rem);font-weight:800;margin-bottom:18px}
.join__copy>p{color:var(--tx-2);font-size:16.5px;margin-bottom:22px}
.join__copy code{
  background:rgba(0,112,192,.20);color:var(--blue-lt);
  padding:2px 7px;border-radius:6px;font-size:14px;
}
.join__list{list-style:none;padding:0;margin:0 0 30px;display:grid;gap:12px}
.join__list li{position:relative;padding-left:26px;color:var(--tx-2);font-size:15px}
.join__list li strong{color:var(--tx)}
.join__list li::before{
  content:"";position:absolute;left:0;top:8px;
  width:9px;height:9px;border-radius:50%;
  background:var(--flame-lt);box-shadow:0 0 12px rgba(255,107,53,.8);
}

/* 公众号卡片 */
.wx{
  padding:30px 28px;border-radius:var(--radius);
  border:1px solid var(--line-2);
  background:linear-gradient(165deg,rgba(0,112,192,.20),rgba(8,13,26,.88));
  box-shadow:0 24px 60px rgba(0,0,0,.5);
  transform-style:preserve-3d;
  will-change:transform;
  transition:transform .35s var(--ease-out), box-shadow .35s;
}
.wx:hover{box-shadow:0 30px 70px rgba(0,112,192,.30)}
.wx>*{position:relative;z-index:1;transform:translateZ(20px)}

.wx__head{display:flex;align-items:center;gap:14px;margin-bottom:22px}
.wx__ico{
  width:42px;height:42px;flex:none;fill:#fff;
  padding:8px;border-radius:12px;
  background:linear-gradient(135deg,#2ECC71,#1FA85C);
  box-shadow:0 8px 22px rgba(46,204,113,.34);
}
.wx__head h3{font-size:16px;margin-bottom:2px}
.wx__name{font-size:15px;font-weight:700;color:var(--blue-lt);letter-spacing:.5px}

.wx__qr{
  position:relative;width:180px;height:180px;margin:0 auto 20px;
  border-radius:14px;overflow:hidden;
  background:#fff;padding:8px;
  box-shadow:0 14px 36px rgba(0,0,0,.45);
}
.wx__qr img{width:100%;height:100%;object-fit:contain;border-radius:8px}

.wx__qr-fallback{
  position:absolute;inset:8px;border-radius:8px;
  display:grid;place-content:center;gap:6px;text-align:center;
  background:repeating-linear-gradient(45deg,#f2f6fb,#f2f6fb 8px,#e6eef7 8px,#e6eef7 16px);
  color:#4A5C72;
}
.wx__qr-fallback span{font-size:13px;font-weight:700}
.wx__qr-fallback small{font-size:11px;line-height:1.5}
.wx__qr-fallback code{background:#dbe6f2;padding:1px 4px;border-radius:4px;font-size:10.5px}

.wx__tip{
  text-align:center;font-size:13.5px;color:var(--tx-2);line-height:1.75;
}
.wx__tip strong{color:var(--tx);font-size:14.5px}

/* 页脚 */
.foot{border-top:1px solid var(--line);padding:40px 0;background:rgba(5,8,15,.7)}
.foot__wrap{display:flex;flex-wrap:wrap;gap:20px;align-items:center;justify-content:space-between}
.foot__brand{display:flex;align-items:center;gap:13px}
.foot__brand img{width:40px;height:auto;object-fit:contain}
.foot__brand strong{font-size:15.5px}
.foot__brand p{font-size:12.5px;color:var(--tx-3)}
.foot__meta{font-size:13px;color:var(--tx-3);max-width:52ch}
.foot__meta strong{color:var(--blue-lt)}

/* ============================================================
   入场动画
   ============================================================ */
.reveal{opacity:0;transform:translateY(26px);transition:opacity .8s var(--ease-out), transform .8s var(--ease-out)}
.reveal.is-in{opacity:1;transform:none}

/* ============================================================
   响应式
   ============================================================ */
@media (max-width:960px){
  .hero__wrap{grid-template-columns:1fr;gap:48px}
  .hero__art{order:-1}
  .stage3d{width:min(280px,66vw)}
  .join__wrap{grid-template-columns:1fr;gap:36px}
  .track{grid-template-columns:56px 1fr;gap:18px}
  .track .bar{grid-column:1/-1}
}

@media (max-width:760px){
  .nav__toggle{display:flex}
  .nav__links{
    position:fixed;inset:70px 16px auto;flex-direction:column;align-items:stretch;
    padding:14px;gap:4px;border-radius:16px;
    background:rgba(8,13,26,.97);
    border:1px solid var(--line-2);
    backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
    box-shadow:0 26px 60px rgba(0,0,0,.65);
    opacity:0;visibility:hidden;transform:translateY(-12px);
    transition:opacity .3s var(--ease), transform .3s var(--ease), visibility .3s;
  }
  .nav__links.is-open{opacity:1;visibility:visible;transform:none}
  .nav__links a{padding:13px 16px}
  .nav__links a::after{display:none}
  .nav__cta{text-align:center}

  .section{padding:80px 0}
  .hero{padding:110px 0 80px}
  .stats{grid-template-columns:repeat(3,1fr);gap:14px}
  .scrollhint{display:none}
  .grid-plane{height:44vh}
  .wx__qr{width:160px;height:160px}
}

@media (max-width:420px){
  .wrap{padding-inline:18px}
  .btn{width:100%;justify-content:center}
  .stats{grid-template-columns:1fr 1fr}
}

/* 降低动态效果偏好 */
@media (prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:.001ms !important;
    animation-iteration-count:1 !important;
    transition-duration:.001ms !important;
    scroll-behavior:auto !important;
  }
  .reveal{opacity:1;transform:none}
  .bar i{width:var(--w)}
  #sky,.grid-plane,.aurora{display:none}
}