/* =========================================================
   base.css —— 设计令牌 + 全局基础样式
   ========================================================= */

/* ============ 0. Tokens ============ */
@property --ang { syntax: '<angle>'; initial-value: 0deg; inherits: false; }

:root{
  --ink:#0B0D10;
  --ink-2:#101318;
  --ink-3:#14181E;
  --paper:#F4F1EA;
  --paper-dim:rgba(244,241,234,.66);
  --paper-faint:rgba(244,241,234,.42);
  --line:rgba(244,241,234,.11);
  --line-strong:rgba(244,241,234,.2);
  --brand:#FF6A2B;
  --brand-deep:#D8430F;
  --sand:#E8C39E;
  --steel:#7C96A4;
  --ok:#4ADE80;
  --warn:#F5C451;
  --danger:#F2545B;

  --font-display:'Instrument Serif','Iowan Old Style','Palatino Linotype',Georgia,'Times New Roman',serif;
  --font-body:'PingFang SC','HarmonyOS Sans SC','Hiragino Sans GB','Noto Sans SC','Microsoft YaHei',system-ui,-apple-system,sans-serif;
  --font-mono:ui-monospace,'SF Mono','Cascadia Mono',Menlo,Consolas,monospace;

  --ease:cubic-bezier(.16,1,.3,1);
  --ease-io:cubic-bezier(.65,0,.35,1);
  --pad:clamp(20px,5vw,72px);
  --maxw:1400px;
  --r:22px;
}

/* ============ 1. Reset ============ */
*,*::before,*::after{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
html:focus-within{scroll-behavior:smooth}
body{
  margin:0;background:var(--ink);color:var(--paper);
  font-family:var(--font-body);font-size:16px;line-height:1.75;
  -webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;
  overflow-x:hidden;
}
img,svg{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
h1,h2,h3,h4,p{margin:0}
button{font:inherit;color:inherit;background:none;border:0}
ul,ol{margin:0;padding:0;list-style:none}
::selection{background:var(--brand);color:#0B0D10}
:focus-visible{outline:2px solid var(--brand);outline-offset:3px;border-radius:4px}
.sr{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}

/* ============ 2. 全局背景纹理 ============ */
body::before{
  content:'';position:fixed;inset:0;z-index:0;pointer-events:none;
  background-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.85' numOctaves='3'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='180' height='180' filter='url(%23n)' opacity='.5'/%3E%3C/svg%3E");
  opacity:.05;mix-blend-mode:overlay;
}
.wrap{position:relative;z-index:1}
.shell{width:100%;max-width:var(--maxw);margin-inline:auto;padding-inline:var(--pad)}

/* ============ 3. 进场动画 ============ */
/*
  修正：原设计把 .rv 的初始状态设为 opacity:0，
  一旦 JS 未执行（被拦截 / 出错 / 用户禁用），内容会永久不可见。
  现在改为「默认可见，只有在 JS 确认可用时才隐藏并接管动画」。
  JS 在 <head> 内同步执行，给 <html> 加 .js 类，
  CSS 仅在 html.js 下才对 .rv 做初始隐藏。
*/
.js .rv{opacity:0;transform:translateY(30px);transition:opacity 1s var(--ease),transform 1s var(--ease);transition-delay:var(--d,0ms)}
.js .rv.in{opacity:1;transform:none}
.js .rv-blur{opacity:0;filter:blur(9px);transform:translateY(18px);transition:opacity 1.1s var(--ease),filter 1.1s var(--ease),transform 1.1s var(--ease);transition-delay:var(--d,0ms)}
.js .rv-blur.in{opacity:1;filter:blur(0);transform:none}

/* ============ 4. 通用按钮 ============ */
.btn{position:relative;display:inline-flex;align-items:center;justify-content:center;gap:10px;
  padding:16px 28px;border-radius:999px;font-size:15.5px;font-weight:600;letter-spacing:.01em;
  overflow:hidden;isolation:isolate;transition:transform .45s var(--ease),box-shadow .45s var(--ease),color .3s,border-color .3s,background .3s;
  will-change:transform}
.btn .arw{width:16px;height:16px;transition:transform .45s var(--ease)}
.btn:hover .arw{transform:translateX(5px)}
.btn-primary{color:#0B0D10;background:linear-gradient(135deg,#FF8A4C,var(--brand) 45%,var(--brand-deep));
  box-shadow:0 8px 26px -10px rgba(255,106,43,.7),inset 0 1px 0 rgba(255,255,255,.35)}
.btn-primary::after{content:'';position:absolute;top:0;left:-60%;width:42%;height:100%;z-index:-1;
  background:linear-gradient(100deg,transparent,rgba(255,255,255,.65),transparent);transform:skewX(-22deg);transition:left .7s var(--ease-io)}
.btn-primary:hover{transform:translateY(-3px);box-shadow:0 18px 44px -12px rgba(255,106,43,.85),inset 0 1px 0 rgba(255,255,255,.4)}
.btn-primary:hover::after{left:120%}
.btn-primary:active{transform:translateY(-1px)}
.btn-ghost{color:var(--paper);border:1px solid var(--line-strong);background:rgba(244,241,234,.03);backdrop-filter:blur(10px)}
.btn-ghost::before{content:'';position:absolute;inset:0;z-index:-1;opacity:0;transition:opacity .45s var(--ease);
  background:radial-gradient(120% 140% at 50% 120%,rgba(255,106,43,.34),transparent 66%)}
.btn-ghost:hover{border-color:rgba(255,106,43,.55);color:#FFD9C4;transform:translateY(-3px);box-shadow:0 16px 40px -18px rgba(255,106,43,.55)}
.btn-ghost:hover::before{opacity:1}
.btn-sm{padding:12px 22px;font-size:14.5px}

/* ============ 5. 动效降级 ============ */
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{animation-duration:.01ms!important;animation-iteration-count:1!important;transition-duration:.01ms!important}
  html:focus-within{scroll-behavior:auto}
  .ecg path{stroke-dashoffset:0!important;animation:none!important}
}