*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}

/* ==================== 主题令牌（浅色默认） ==================== */
:root{
  color-scheme:light;
  --font:-apple-system,BlinkMacSystemFont,"SF Pro Text","PingFang SC","HarmonyOS Sans SC","Microsoft YaHei",sans-serif;
  --font-display:"Manrope",var(--font);

  /* 基底 */
  --bg:#f0f2f8;
  --mask:#f0f2f8;
  --aurora-a:rgba(99,102,241,.15);
  --aurora-b:rgba(6,182,212,.12);
  --aurora-c:rgba(168,85,247,.10);
  --aurora-d:rgba(99,102,241,.06);
  --noise-opacity:.025;

  /* 玻璃面 */
  --glass:rgba(255,255,255,.72);
  --glass-strong:rgba(255,255,255,.88);
  --glass-hover:rgba(255,255,255,.95);
  --sheen:rgba(255,255,255,.9);
  --glass-edge:rgba(255,255,255,.85);
  --stroke:rgba(15,20,50,.08);
  --stroke-strong:rgba(15,20,50,.16);
  --inner-bright:inset 0 1px 0 rgba(255,255,255,.8);

  /* 文字 */
  --text:#111322;
  --text-2:#555770;
  --text-3:#8e90a6;

  /* 强调 */
  --accent:#6366f1;
  --accent-2:#06b6d4;
  --accent-soft:rgba(99,102,241,.10);
  --accent-contrast:#ffffff;
  --ring:rgba(99,102,241,.20);
  --glow:0 0 0 1px rgba(99,102,241,.25),0 0 16px -2px rgba(99,102,241,.30);

  --navbar-bg:rgba(240,242,248,.75);

  /* 圆角 */
  --radius:20px;
  --radius-lg:28px;
  --radius-sm:12px;
}
[data-theme="dark"]{
  color-scheme:dark;
  --bg:#0a0a10;
  --mask:#0a0a10;
  --aurora-a:rgba(99,102,241,.12);
  --aurora-b:rgba(6,182,212,.08);
  --aurora-c:rgba(168,85,247,.08);
  --aurora-d:rgba(99,102,241,.04);
  --noise-opacity:.02;

  --glass:rgba(255,255,255,.04);
  --glass-strong:rgba(255,255,255,.07);
  --glass-hover:rgba(255,255,255,.10);
  --sheen:rgba(255,255,255,.05);
  --glass-edge:rgba(255,255,255,.08);
  --stroke:rgba(255,255,255,.06);
  --stroke-strong:rgba(255,255,255,.12);
  --inner-bright:inset 0 1px 0 rgba(255,255,255,.05);

  --text:#e8eaf0;
  --text-2:#8a8ca0;
  --text-3:#5a5c70;

  --accent:#818cf8;
  --accent-2:#22d3ee;
  --accent-soft:rgba(129,140,248,.10);
  --accent-contrast:#0b0d1a;
  --ring:rgba(129,140,248,.20);
  --glow:0 0 0 1px rgba(129,140,248,.25),0 0 16px -2px rgba(129,140,248,.30);

  --navbar-bg:rgba(10,10,16,.75);
}

html{scroll-behavior:smooth}

/* ==================== 背景：极光 + 噪点 ==================== */
body{
  font-family:var(--font);
  color:var(--text);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
  background-color:var(--bg);
  transition:background-color .5s ease,color .5s ease;
}
body::before{
  content:"";position:fixed;inset:-20%;
  z-index:-2;pointer-events:none;
  background:
    radial-gradient(44% 44% at 20% 16%,var(--aurora-a),transparent 70%),
    radial-gradient(42% 42% at 82% 74%,var(--aurora-b),transparent 72%),
    radial-gradient(36% 36% at 62% 6%,var(--aurora-c),transparent 72%),
    radial-gradient(30% 30% at 40% 96%,var(--aurora-d),transparent 72%);
  filter:blur(46px);
  animation:aurora 30s ease-in-out infinite alternate;
  will-change:transform;
}
body::after{
  content:"";position:fixed;inset:0;z-index:2000;pointer-events:none;opacity:var(--noise-opacity);
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}
@keyframes aurora{
  0%{transform:translate3d(0,0,0) rotate(0deg) scale(1)}
  50%{transform:translate3d(2%,-3%,0) rotate(3deg) scale(1.04)}
  100%{transform:translate3d(-2%,2%,0) rotate(-3deg) scale(1.02)}
}

.container{max-width:1160px;margin:0 auto;padding:0 24px}
section>.container{position:relative;z-index:1}

/* ============ 玻璃面板通用 ============ */
.glass{
  position:relative;
  background:var(--glass);
  border:1px solid var(--stroke);
  backdrop-filter:blur(28px) saturate(1.6);
  -webkit-backdrop-filter:blur(28px) saturate(1.6);
  border-radius:var(--radius);
}
.glass::after{
  content:"";position:absolute;inset:0;
  border-radius:inherit;
  background:linear-gradient(160deg,rgba(255,255,255,.15) 0%,transparent 35%);
  opacity:.6;
  pointer-events:none;
}
.glass::before{
  content:"";position:absolute;inset:0;z-index:2;
  pointer-events:none;
}

/* ==================== 导航栏 ==================== */
.navbar{position:fixed;top:0;left:0;right:0;z-index:1000;border-bottom:1px solid transparent;transition:background-color .4s ease,border-color .4s ease}
.navbar.scrolled{background:var(--navbar-bg);backdrop-filter:blur(22px) saturate(1.4);-webkit-backdrop-filter:blur(22px) saturate(1.4);border-color:var(--stroke)}
.nav-content{display:flex;align-items:center;justify-content:space-between;height:64px}
.logo{font-size:17px;font-weight:650;text-decoration:none;color:var(--text);letter-spacing:-.2px;display:flex;align-items:center}
.logo-icon{width:28px;height:28px;border-radius:8px;margin-right:10px;display:block;object-fit:cover}
.nav-right{display:flex;align-items:center;gap:8px}
.nav-links{display:flex;align-items:center;gap:2px;padding:4px;background:var(--glass);border:1px solid var(--stroke);border-radius:999px;backdrop-filter:blur(18px) saturate(1.4);-webkit-backdrop-filter:blur(18px) saturate(1.4)}
.nav-links a{color:var(--text-2);text-decoration:none;font-size:13.5px;font-weight:520;padding:7px 14px;border-radius:999px;transition:color .2s ease,background .2s ease}
.nav-links a:hover{color:var(--text);background:var(--glass-hover)}
.nav-cta{color:var(--text)!important;border:1px solid var(--stroke-strong)!important}
.nav-cta:hover{color:var(--accent)!important;border-color:var(--accent)!important;box-shadow:var(--glow)}
.theme-toggle{width:36px;height:36px;display:flex;align-items:center;justify-content:center;border:1px solid var(--stroke-strong);border-radius:999px;background:var(--glass);color:var(--text);cursor:pointer;backdrop-filter:blur(18px) saturate(1.4);-webkit-backdrop-filter:blur(18px) saturate(1.4);transition:color .2s ease,border-color .2s ease,box-shadow .25s ease}
.theme-toggle:hover{border-color:var(--accent);color:var(--accent);box-shadow:var(--glow)}
.theme-toggle:active{transform:scale(.93)}
.theme-toggle svg{width:16px;height:16px}
.theme-toggle .icon-dark{display:none}
.theme-toggle .icon-light{display:block}
[data-theme="dark"] .theme-toggle .icon-dark{display:block}
[data-theme="dark"] .theme-toggle .icon-light{display:none}

:focus-visible{outline:2px solid var(--accent);outline-offset:3px;border-radius:6px}

/* ============ 汉堡菜单按钮 ============ */
.hamburger{display:none;width:36px;height:36px;align-items:center;justify-content:center;border:1px solid var(--stroke-strong);border-radius:999px;background:var(--glass);cursor:pointer;backdrop-filter:blur(18px) saturate(1.4);-webkit-backdrop-filter:blur(18px) saturate(1.4);transition:border-color .2s ease,background .2s ease,box-shadow .25s ease;flex-direction:column;gap:4px;padding:0;position:relative;z-index:1001}
.hamburger span{display:block;width:15px;height:1.5px;background:var(--text);border-radius:2px;transition:transform .3s cubic-bezier(.4,0,.2,1),opacity .3s ease}
.hamburger[aria-expanded="true"] span:nth-child(1){transform:translateY(5.5px) rotate(45deg)}
.hamburger[aria-expanded="true"] span:nth-child(2){opacity:0}
.hamburger[aria-expanded="true"] span:nth-child(3){transform:translateY(-5.5px) rotate(-45deg)}
.hamburger:hover{border-color:var(--accent);box-shadow:var(--glow)}
.hamburger[aria-expanded="true"]{background:var(--accent);border-color:var(--accent);box-shadow:var(--glow)}
.hamburger[aria-expanded="true"] span{background:#fff}

/* ============ 移动端悬浮菜单 ============ */
.mobile-menu{
  position:fixed;
  top:62px;right:18px;
  z-index:1000;
  min-width:200px;
  padding:12px;
  background:var(--glass-strong);
  border:1px solid var(--stroke);
  border-radius:16px;
  backdrop-filter:blur(28px) saturate(1.6);
  -webkit-backdrop-filter:blur(28px) saturate(1.6);
  flex-direction:column;
  gap:0px;
  opacity:0;
  visibility:hidden;
  transform:translateY(-8px);
  transform-origin:top right;
  pointer-events:none;
  transition:opacity .18s ease,transform .18s ease,visibility 0s .18s;
}
.mobile-menu.open{
  opacity:1;
  visibility:visible;
  transform:translateY(0);
  pointer-events:auto;
  transition:opacity .18s ease,transform .18s ease,visibility 0s 0s;
}
.mobile-menu a{
  color:var(--text);
  text-decoration:none;
  font-size:14.5px;
  font-weight:520;
  padding:12px 14px;
  border-radius:var(--radius-sm);
  transition:background .15s ease,color .15s ease;
  white-space:nowrap;
}
.mobile-menu a:hover{background:var(--accent-soft);color:var(--accent)}
.mobile-menu .nav-cta{
  border:1px solid var(--stroke-strong);
  margin-top:2px;
  text-align:center;
  justify-content:center;
  display:flex;
}
.mobile-menu .nav-cta:hover{border-color:var(--accent);color:var(--accent);background:var(--accent-soft);box-shadow:var(--glow)}

/* ==================== Hero ==================== */
.hero{position:relative;padding:160px 0 90px;overflow:hidden}
.hero-grid{display:grid;grid-template-columns:1.05fr .95fr;gap:48px;align-items:center}
.hero-badge{display:inline-flex;align-items:center;gap:8px;padding:6px 16px 6px 12px;border-radius:999px;font-size:12.5px;font-weight:560;color:var(--text-2);letter-spacing:.2px;margin-bottom:28px;border:1px solid var(--stroke);background:var(--glass);backdrop-filter:blur(16px) saturate(1.4);-webkit-backdrop-filter:blur(16px) saturate(1.4)}
.hero-badge .badge-dot{width:7px;height:7px;border-radius:50%;background:var(--accent);box-shadow:0 0 6px var(--accent);animation:pulse-dot 2.5s ease-in-out infinite}
.hero-badge .badge-version{font-family:var(--font-display);font-weight:650;color:var(--text)}
@keyframes pulse-dot{0%,100%{opacity:1;box-shadow:0 0 6px var(--accent)}50%{opacity:.6;box-shadow:0 0 12px var(--accent)}}
.hero-title{font-size:clamp(38px,5vw,58px);font-weight:700;line-height:1.08;letter-spacing:-.028em;margin-bottom:20px;text-wrap:balance}
.hero-title .line{display:block}
.aurora-text{
  background:linear-gradient(135deg,var(--accent),var(--accent-2));
  background-size:200% 100%;
  -webkit-background-clip:text;background-clip:text;color:transparent;
  animation:sheen 7s linear infinite;
}
@keyframes sheen{to{background-position:200% 0}}
.hero-desc{font-size:15.5px;color:var(--text-2);line-height:1.85;margin-bottom:36px;max-width:34em}
.hero-actions{display:flex;gap:12px;margin-bottom:48px}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 26px;border-radius:999px;font-size:14px;font-weight:560;text-decoration:none;transition:all .25s ease;border:none;cursor:pointer;font-family:var(--font)}
.btn-primary{
  position:relative;overflow:hidden;
  background:linear-gradient(135deg,#6366f1,#818cf8 50%,#6366f1);
  background-size:200% 100%;
  color:#fff;font-weight:600;
}
.btn-primary::after{content:"";position:absolute;inset:0;background:linear-gradient(105deg,transparent 42%,rgba(255,255,255,.55) 50%,transparent 58%);transform:translateX(-130%);transition:transform .7s ease}
.btn-primary:hover::after{transform:translateX(130%)}
.btn-primary:hover{transform:translateY(-2px);box-shadow:var(--glow)}
.btn-primary:active{transform:translateY(0)}
.btn-ghost{background:var(--glass);color:var(--text);border:1px solid var(--stroke-strong);backdrop-filter:blur(16px) saturate(1.3);-webkit-backdrop-filter:blur(16px) saturate(1.3)}
.btn-ghost:hover{color:var(--accent);border-color:var(--accent);transform:translateY(-1px);box-shadow:var(--glow)}
.hero-stats{display:flex;align-items:baseline;gap:0}
.stat{padding:0 28px;position:relative}
.stat:first-child{padding-left:0}
.stat + .stat::before{content:"";position:absolute;left:0;top:10%;bottom:10%;width:1px;background:var(--stroke)}
.stat .stat-label{display:block;font-size:11px;color:var(--text-3);text-transform:uppercase;letter-spacing:.16em;margin-top:4px}
.stat-num{font-family:var(--font-display);font-size:25px;font-weight:650;color:var(--text);letter-spacing:-.02em;font-variant-numeric:tabular-nums;font-feature-settings:"tnum"}

.hero-content,.hero-visual{position:relative;z-index:2}
.hero-visual{display:flex;justify-content:center;align-items:center;padding-right:6px}
.hero-shot{position:relative;width:280px;max-width:92%;animation:float 7s ease-in-out infinite}
.hero-shot-glow{position:absolute;inset:-22% -14%;z-index:-1;border-radius:50%;background:radial-gradient(55% 55% at 50% 44%,var(--ring),var(--aurora-b) 55%,transparent 72%);filter:blur(50px);opacity:.5;animation:breathe 6s ease-in-out infinite;will-change:transform}
.hero-shot::after{content:"";position:absolute;left:18%;right:18%;bottom:-3%;height:26px;z-index:-2;border-radius:50%;background:radial-gradient(50% 50% at 50% 50%,rgba(15,20,50,.12),transparent 70%);filter:blur(14px);animation:ground 7s ease-in-out infinite}
.hero-shot img{width:100%;height:auto;display:block;will-change:transform}
@keyframes float{0%,100%{transform:translateY(0)}50%{transform:translateY(-12px)}}
@keyframes breathe{0%,100%{opacity:.45;transform:scale(1) translateY(0)}50%{opacity:.8;transform:scale(1.12) translateY(-3px)}}
@keyframes ground{0%,100%{opacity:.5;transform:scaleX(1)}50%{opacity:.32;transform:scaleX(.86)}}

/* ==================== 区块标题 ==================== */
section{position:relative;scroll-margin-top:72px;z-index:1;padding:88px 0}
.section-header{text-align:center;margin-bottom:48px}
.section-tag{display:inline-flex;align-items:center;gap:10px;padding:5px 14px;border-radius:999px;font-family:var(--font-display);font-size:11px;font-weight:650;color:var(--accent);text-transform:uppercase;letter-spacing:.22em;margin-bottom:16px;background:var(--glass);border:1px solid var(--stroke);backdrop-filter:blur(16px) saturate(1.4);-webkit-backdrop-filter:blur(16px) saturate(1.4)}
.section-tag .idx{opacity:.55;font-weight:500}
.section-header h2{font-size:clamp(26px,3.6vw,40px);font-weight:700;letter-spacing:-.02em;text-wrap:balance}
.section-header h2 .thin{font-weight:460;color:var(--text-2)}
.section-header .sub{margin-top:10px;font-size:14px;color:var(--text-2)}

/* ==================== 功能 ==================== */
.features-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.feature-card{position:relative;padding:28px 24px 26px;border-radius:var(--radius);overflow:hidden;transition:transform .4s cubic-bezier(.16,1,.3,1),border-color .3s ease,box-shadow .3s ease}
.feature-card::before{content:"";position:absolute;inset:0 0 auto;height:1px;background:linear-gradient(90deg,transparent,rgba(255,255,255,.4),transparent);opacity:0;transition:opacity .4s ease;z-index:3}
.feature-card::after{content:"";position:absolute;width:180px;height:180px;border-radius:50%;background:radial-gradient(circle at center,var(--ring),transparent 70%);transform:translate(-50%,-50%);filter:blur(28px);opacity:0;z-index:1;pointer-events:none;transition:opacity .4s ease;left:var(--gx,50%);top:var(--gy,0%);will-change:left,top}
.feature-card:hover{transform:translateY(-4px);border-color:var(--accent);box-shadow:var(--glow)}
.feature-card:hover::before{opacity:1}
.feature-card:hover::after{opacity:.6}
.feature-card .fi{position:relative;z-index:2}
.fi{width:44px;height:44px;display:flex;align-items:center;justify-content:center;border-radius:var(--radius-sm);background:var(--accent-soft);color:var(--accent);margin-bottom:20px;border:1px solid var(--stroke);transition:transform .4s cubic-bezier(.34,1.56,.64,1),background .3s ease,color .3s ease,box-shadow .3s ease}
.feature-card:hover .fi{transform:rotate(-8deg) scale(1.08);background:linear-gradient(135deg,var(--accent),var(--accent-2));color:var(--accent-contrast);box-shadow:var(--glow)}
.fi svg{width:22px;height:22px}
.feature-card h3{position:relative;z-index:2;font-size:15.5px;font-weight:640;letter-spacing:-.01em;margin-bottom:6px}
.feature-card p{position:relative;z-index:2;font-size:13px;color:var(--text-2);line-height:1.7}

@media(max-width:620px){
  .features-grid{
    grid-template-columns:1fr 1fr;gap:18px;
    margin:0;
  }
  .feature-card{
    padding:18px 14px 16px;
    border-radius:16px;
  }
  .feature-card .fi{
    width:36px;height:36px;border-radius:var(--radius-sm);
    margin-bottom:12px;
  }
  .fi svg{width:17px;height:17px}
  .feature-card h3{font-size:13.5px;font-weight:620;margin-bottom:4px}
  .feature-card p{font-size:11.5px;line-height:1.55;color:var(--text-3)}
}

/* ============ 预览（中央展示台） ============ */
.showcase{max-width:860px;margin:0 auto;padding:44px 36px 40px;display:grid;grid-template-columns:280px 1fr;gap:40px;align-items:center;border-radius:var(--radius-lg)}
.showcase-stage{position:relative;width:280px}
.showcase-shot{position:relative}
.showcase-glow{position:absolute;inset:-20% -12%;z-index:-1;border-radius:50%;background:radial-gradient(55% 55% at 50% 44%,var(--ring),transparent 72%);filter:blur(50px);opacity:.4}
.showcase-shot img{width:100%;height:auto;display:block;transition:opacity .3s ease,transform .4s cubic-bezier(.16,1,.3,1);animation:float 7s ease-in-out infinite}
.showcase-shot img.swap-out{opacity:0;transform:translateY(12px) scale(.98)}
.showcase-right{display:flex;flex-direction:column;justify-content:center}
.showcase-caption{text-align:left}
.showcase-caption h3{font-size:20px;font-weight:680;letter-spacing:-.01em;margin-bottom:6px}
.showcase-caption p{font-size:13.5px;color:var(--text-2);max-width:24em}
.showcase-thumbs{display:flex;flex-wrap:wrap;gap:7px;margin-top:24px}
.thumb{position:relative;display:inline-flex;align-items:center;gap:6px;padding:6px 12px;border-radius:999px;border:1px solid var(--stroke);background:var(--glass);color:var(--text-2);font-family:var(--font);font-size:12px;font-weight:560;cursor:pointer;transition:all .22s ease;white-space:nowrap}
.thumb span{width:16px;height:16px;display:flex;align-items:center;justify-content:center;border-radius:50%;background:var(--accent-soft);color:var(--accent);font-size:10px;font-weight:650;transition:all .22s ease}
.thumb:hover{border-color:var(--stroke-strong);color:var(--text);transform:translateY(-1px)}
.thumb.active{border-color:var(--accent);color:var(--text);box-shadow:var(--glow)}
.thumb.active span{background:linear-gradient(135deg,var(--accent),var(--accent-2));color:var(--accent-contrast);transform:scale(1.06)}

@media(max-width:620px){
  .glass{border:none}
  .showcase{
    display:flex;flex-direction:column;
    padding:20px 12px 18px;
    gap:0;
    border-radius:var(--radius);
    border:none;
  }
  .showcase-stage{width:70%;max-width:240px;margin:0 auto;overflow:visible;border-radius:16px}
  .showcase-shot{position:relative;height:0;padding-bottom:170%;overflow:hidden;border-radius:16px}
  .showcase-shot img{position:absolute;top:6%;left:0;width:100%;height:94%;object-fit:cover;object-position:top;animation-duration:9s}
  .showcase-right{width:100%;text-align:center}
  .showcase-caption{margin-top:10px;text-align:center}
  .showcase-caption h3{font-size:15px;margin-bottom:2px}
  .showcase-caption p{font-size:11.5px;color:var(--text-3);max-width:none}
  .showcase-thumbs{
    display:flex;flex-wrap:wrap;justify-content:center;gap:6px;
    margin-top:14px;
    padding:0;
  }
  .thumb{
    padding:7px 14px;font-size:12.5px;font-weight:550;
    justify-content:center;
    border-radius:20px;letter-spacing:.01em;
    border:none;
    background:var(--accent-soft);color:var(--accent);
    transition:all .2s ease;
  }
  .thumb.active{background:linear-gradient(135deg,var(--accent),var(--accent-2));color:#fff;box-shadow:0 2px 12px rgba(99,102,241,.3)}
  .thumb:active{transform:scale(.95)}
  .thumb span{display:none}
}

/* ==================== 下载 ==================== */
.download-grid{display:grid;grid-template-columns:1fr 1fr;gap:14px;max-width:640px;margin:0 auto}
.dl-card{display:flex;align-items:center;gap:20px;text-align:left;padding:24px 26px;border-radius:var(--radius);text-decoration:none;color:var(--text);transition:transform .3s ease,border-color .3s ease,box-shadow .3s ease}
.dl-card:hover{transform:translateY(-3px);border-color:var(--accent);box-shadow:var(--glow)}
.dl-icon{flex:0 0 auto;width:44px;height:44px;display:flex;align-items:center;justify-content:center;border-radius:var(--radius-sm);background:var(--accent-soft);color:var(--accent);border:1px solid var(--stroke);transition:box-shadow .3s ease}
.dl-card:hover .dl-icon{box-shadow:var(--glow)}
.dl-icon svg{width:22px;height:22px}
.dl-meta h3{font-size:15.5px;font-weight:640;margin-bottom:2px}
.dl-meta p{font-size:13px;color:var(--text-2)}

/* ==================== 社区 ==================== */
.community-inner{text-align:center;padding:68px 36px;border-radius:var(--radius-lg)}
.community-inner h2{font-size:25px;font-weight:700;letter-spacing:-.02em;margin-bottom:6px}
.community-inner p{color:var(--text-2);margin-bottom:28px;font-size:14.5px}
.community-links{display:flex;gap:10px;justify-content:center;flex-wrap:wrap}

/* ==================== 页脚 ==================== */
footer{padding:36px 0;border-top:1px solid var(--stroke);text-align:center;color:var(--text-3);font-size:12.5px;position:relative;z-index:1}
.foot-links{display:flex;gap:10px;justify-content:center;align-items:center;margin-bottom:10px}
.foot-links a{color:var(--text-3);text-decoration:none;transition:color .2s ease}
.foot-links a:hover{color:var(--accent)}
.foot-links span{opacity:.4}

/* ==================== 回到顶部 ==================== */
.back-to-top{position:fixed;bottom:28px;right:28px;z-index:900;width:42px;height:42px;display:flex;align-items:center;justify-content:center;border-radius:999px;border:1px solid var(--stroke-strong);background:var(--glass);color:var(--text);cursor:pointer;backdrop-filter:blur(18px) saturate(1.4);-webkit-backdrop-filter:blur(18px) saturate(1.4);opacity:0;transform:translateY(14px);pointer-events:none;transition:opacity .3s ease,transform .3s ease,border-color .2s ease,color .2s ease,box-shadow .25s ease}
.back-to-top.visible{opacity:1;transform:none;pointer-events:auto}
.back-to-top:hover{border-color:var(--accent);color:var(--accent);box-shadow:var(--glow);transform:translateY(-2px)}
.back-to-top:active{transform:scale(.92)}
.back-to-top svg{width:18px;height:18px}

/* ==================== 入场动效 ==================== */
.reveal{opacity:0;transform:translateY(16px);transition:opacity .5s ease,transform .5s cubic-bezier(.16,1,.3,1)}
.reveal.visible{opacity:1;transform:none}
.features-grid .reveal:nth-child(2){transition-delay:.05s}
.features-grid .reveal:nth-child(3){transition-delay:.1s}
.fade-el{opacity:0;animation:fadeUp .5s cubic-bezier(.16,1,.3,1) forwards}
.hero-content .fade-el:nth-child(1){animation-delay:.05s}
.hero-content .fade-el:nth-child(2){animation-delay:.1s}
.hero-content .fade-el:nth-child(3){animation-delay:.15s}
.hero-content .fade-el:nth-child(4){animation-delay:.2s}
.hero-content .fade-el:nth-child(5){animation-delay:.25s}
.hero-visual .fade-el{animation-delay:.2s}
@keyframes fadeUp{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:none}}

/* ==================== 响应式 ==================== */
@media(max-width:920px){
  .hero{padding:140px 0 72px}
  .hero-grid{grid-template-columns:1fr;text-align:center;gap:48px}
  .hero-desc{margin-left:auto;margin-right:auto}
  .hero-actions{justify-content:center}
  .hero-stats{justify-content:center}
  .hero-visual{margin-top:8px}
  .features-grid{grid-template-columns:1fr 1fr}
}
@media(max-width:620px){
  .hamburger{display:flex}
  .nav-links{display:none}
  .nav-cta{margin-left:auto}
  .download-grid{grid-template-columns:1fr}
  .dl-card{padding:18px 16px;gap:14px}
  .dl-icon{width:38px;height:38px}
  .dl-meta h3{font-size:14px}
  .dl-meta p{font-size:12px}
  .hero-stats{flex-wrap:wrap;gap:16px 0}
  .stat + .stat::before{display:none}
  .stat:nth-child(n+2){padding-left:0}
  body::before{filter:blur(28px);animation-duration:45s}
  .hero{padding:120px 0 56px}
  .hero-badge{padding:5px 12px 5px 10px;font-size:11.5px}
  .hero-desc{font-size:14px;line-height:1.75}
  .hero-actions .btn{padding:11px 22px;font-size:13px}
  .hero-stats{gap:0}
  .stat{padding:0 20px}
  .stat .stat-label{font-size:10px}
  .stat-num{font-size:22px}
  .back-to-top{bottom:18px;right:18px;width:40px;height:40px}
  section{padding:56px 0}
  .section-header{margin-bottom:24px}
  .section-header h2{font-size:22px}
  .section-header .sub{font-size:12.5px;margin-top:8px}
  .section-tag{margin-bottom:12px;padding:4px 11px;font-size:10px}
  .community-inner{padding:40px 20px}
  .community-inner h2{font-size:20px}
  .community-inner p{font-size:13px;margin-bottom:20px}
  .community-links{gap:8px}
  .community-links .btn{padding:10px 20px;font-size:13px}
  footer{padding:28px 0;font-size:11.5px}
  .foot-links{gap:8px}
}

@media(prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation:none!important;transition:none!important}
  .reveal,.fade-el{opacity:1;transform:none;filter:none}
  body::before{animation:none}
}