/* ============================================================
   公共样式（三页共享）
   抽取自 首页 / 视频页 / 文章页 中逐字一致的基础与占位图样式。
   各页面通过 <link rel="stylesheet" href="style/common.css"> 引用。
   ============================================================ */

:root{
  --brand-900:#083A63;
  --brand-800:#0B4A7E;
  --brand-700:#0F5E96;
  --brand-600:#1577B6;
  --brand-500:#2489CC;
  --brand-400:#4FA6DC;
  --brand-300:#9BD0F2;
  --brand-200:#C7E5F7;
  --brand-100:#E3F1FB;
  --brand-050:#F2F8FE;
  --cyan-600:#0E9BB8;
  --cyan-500:#17A9C4;
  --cyan-400:#3FB9D4;
  --warm-600:#DC4A28;
  --warm-400:#F58A5B;
  --ink:#16232E;
  --ink-2:#3E4E5C;
  --ink-3:#667585;
  --line:#E1ECF6;
  --line-2:#EDF3FA;
  --bg:#F2F7FC;
  --white:#ffffff;
  --r:10px;
  --r-sm:8px;
  --sh-sm:0 2px 10px rgba(16,58,96,.07);
  --sh:0 8px 26px rgba(16,58,96,.10);
  --sh-lg:0 20px 48px rgba(12,52,92,.16);
  --maxw:1240px;
  --ease:.26s cubic-bezier(.4,.2,.2,1);
}

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

html{scroll-behavior:smooth}

a{color:inherit;text-decoration:none}

button{font:inherit;color:inherit;background:none;border:0;cursor:pointer;padding:0}

.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}

.ph{position:absolute;inset:0;overflow:hidden;background:#E9F3FC}

.ph::before{content:"";position:absolute;inset:0;background:radial-gradient(115% 90% at 84% 12%,rgba(255,255,255,.9),transparent 58%),radial-gradient(95% 85% at 12% 18%,rgba(140,196,236,.85),transparent 62%),radial-gradient(120% 100% at 72% 96%,rgba(160,210,240,.85),transparent 60%),linear-gradient(135deg,#E7F2FC,#DCEBF9)}

.ph::after{content:"";position:absolute;inset:0;background-image:radial-gradient(rgba(255,255,255,.6) 1px,transparent 1px);background-size:15px 15px;opacity:.42;-webkit-mask-image:linear-gradient(150deg,#000,transparent 72%);mask-image:linear-gradient(150deg,#000,transparent 72%)}

.ph.b::before{background:radial-gradient(115% 90% at 84% 12%,rgba(255,255,255,.9),transparent 58%),radial-gradient(95% 85% at 14% 20%,rgba(150,205,235,.9),transparent 62%),radial-gradient(120% 100% at 70% 96%,rgba(150,205,235,.80),transparent 60%),linear-gradient(135deg,#E1EFFC,#E0F4FA)}

.ph.c::before{background:radial-gradient(110% 88% at 82% 14%,rgba(255,255,255,.88),transparent 58%),radial-gradient(92% 82% at 16% 22%,rgba(158,212,238,.92),transparent 62%),radial-gradient(118% 98% at 74% 94%,rgba(176,214,238,.82),transparent 60%),linear-gradient(135deg,#E6F1FC,#E1F0FA)}

.ph.d::before{background:radial-gradient(110% 86% at 80% 16%,rgba(255,255,255,.88),transparent 56%),radial-gradient(92% 82% at 18% 26%,rgba(178,214,244,.95),transparent 62%),radial-gradient(118% 96% at 66% 92%,rgba(160,204,238,.85),transparent 60%),linear-gradient(150deg,#E6F1FC,#E4F2FB)}

.svg-sprite{position:absolute}

/* 页头 LOGO 图片（替代原 SVG 图标 + 文字标识） */
.brand-img{display:block;width:auto;flex:none}