/* ============================================================
   GRID & STEEL · 输变电装备用钢指南
   杂志编辑 × 工业实用：衬线大标题 / 细线网格 / 编号章节
   主色 #D83A2E · 底色 #F5F3F3
   ============================================================ */
:root{
  --red:#D83A2E;
  --red-deep:#B22B20;
  --bg:#F5F3F3;
  --paper:#FFFFFF;
  --ink:#1C1B1A;
  --ink-2:#57534E;
  --ink-3:#8A8580;
  --line:#E4E0DE;
  --dark:#191716;
  --dark-2:#242120;
  --dark-line:#37322F;
  --serif:"Noto Serif SC","Source Han Serif SC","STSong","SimSun",serif;
  --sans:"Noto Sans SC","Source Han Sans SC","Microsoft YaHei",sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  font-family:var(--sans);
  background:var(--bg);
  color:var(--ink);
  font-size:16px;
  line-height:1.9;
  overflow-x:hidden;
  -webkit-font-smoothing:antialiased;
}
img,svg{display:block;max-width:100%}
a{color:inherit;text-decoration:none}
ul,ol{list-style:none}
.wrap{width:min(1180px,92%);margin:0 auto}
.en{font-family:Georgia,"Times New Roman",serif}

/* ---------- 顶部导航 ---------- */
.site-head{
  position:sticky;top:0;z-index:50;
  background:rgba(245,243,243,.92);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.head-in{display:flex;align-items:center;justify-content:space-between;height:76px}
.logo{display:flex;align-items:center;gap:12px}
.logo-mark{width:34px;height:34px}
.logo-txt{display:flex;flex-direction:column;line-height:1.25}
.logo-txt b{font-family:var(--serif);font-size:19px;letter-spacing:2px}
.logo-txt span{font-size:10px;letter-spacing:3.5px;color:var(--ink-3);text-transform:uppercase}
.nav{display:flex;align-items:center;gap:38px}
.nav a{font-size:15px;letter-spacing:1px;color:var(--ink-2);position:relative;padding:6px 0}
.nav a::after{content:"";position:absolute;left:0;bottom:0;width:0;height:2px;background:var(--red);transition:width .25s}
.nav a:hover{color:var(--ink)}
.nav a:hover::after,.nav a[aria-current]::after{width:100%}
.nav a[aria-current]{color:var(--ink);font-weight:600}
.nav .nav-en{font-size:10px;letter-spacing:1.5px;color:var(--ink-3);display:block;line-height:1}
.nav-item{text-align:left}
.burger{display:none;background:none;border:1px solid var(--line);border-radius:4px;width:44px;height:40px;cursor:pointer;position:relative}
.burger span{position:absolute;left:10px;right:10px;height:2px;background:var(--ink);transition:.2s}
.burger span:nth-child(1){top:12px}.burger span:nth-child(2){top:19px}.burger span:nth-child(3){top:26px}
@media (max-width:900px){
  .nav{
    display:none;position:absolute;top:76px;left:0;right:0;
    background:var(--paper);border-bottom:1px solid var(--line);
    flex-direction:column;align-items:flex-start;gap:0;padding:10px 5%;
  }
  .nav.open{display:flex}
  .nav a{padding:14px 0;width:100%;border-bottom:1px solid var(--line);font-size:16px}
  .burger{display:block}
}

/* ---------- 首屏 ---------- */
.hero{position:relative;overflow:hidden;border-bottom:1px solid var(--line);background:var(--bg)}
.hero-grid-bg{
  position:absolute;inset:0;opacity:.5;pointer-events:none;
  background-image:
    linear-gradient(var(--line) 1px,transparent 1px),
    linear-gradient(90deg,var(--line) 1px,transparent 1px);
  background-size:64px 64px;
  mask-image:radial-gradient(ellipse 90% 80% at 70% 30%,#000 30%,transparent 75%);
  -webkit-mask-image:radial-gradient(ellipse 90% 80% at 70% 30%,#000 30%,transparent 75%);
}
.hero-in{position:relative;display:grid;grid-template-columns:1.25fr .75fr;gap:64px;align-items:center;padding:110px 0 120px}
.kicker{display:flex;align-items:center;gap:12px;font-size:13px;letter-spacing:4px;color:var(--red);margin-bottom:28px}
.kicker::before{content:"";width:34px;height:2px;background:var(--red)}
.hero h1{
  font-family:var(--serif);font-weight:900;
  font-size:clamp(38px,5vw,60px);line-height:1.32;letter-spacing:1px;
}
.hero h1 em{font-style:normal;color:var(--red)}
.hero .hero-en{margin-top:16px;font-size:14px;letter-spacing:2px;color:var(--ink-3)}
.hero .lead{margin-top:30px;font-size:17px;color:var(--ink-2);max-width:34em}
.hero-cta{margin-top:42px;display:flex;gap:18px;flex-wrap:wrap}
.btn{
  display:inline-flex;align-items:center;gap:10px;
  padding:15px 32px;font-size:15px;letter-spacing:1px;border-radius:2px;
  transition:.2s;border:1px solid var(--ink);
}
.btn-red{background:var(--red);border-color:var(--red);color:#fff}
.btn-red:hover{background:var(--red-deep)}
.btn-ghost{color:var(--ink)}
.btn-ghost:hover{background:var(--ink);color:var(--bg)}
.hero-side{position:relative}
.hero-figure{border:1px solid var(--line);background:var(--paper);padding:22px 22px 14px;border-radius:3px}
.hero-figure figcaption{font-size:11.5px;color:var(--ink-3);letter-spacing:1px;padding:10px 2px 4px;display:flex;justify-content:space-between}
.hero-stats{position:absolute;left:-26px;bottom:-34px;background:var(--dark);color:#EDEAE8;padding:22px 26px;border-radius:3px;display:flex;gap:30px;box-shadow:0 20px 40px rgba(28,27,26,.18)}
.hero-stats div b{font-family:Georgia,serif;font-size:27px;color:#fff;display:block;line-height:1.2}
.hero-stats div b i{font-style:normal;color:var(--red);font-size:16px;margin-left:2px}
.hero-stats div span{font-size:11.5px;color:#A39C97;letter-spacing:1px}
@media (max-width:900px){
  .hero-in{grid-template-columns:1fr;padding:72px 0 96px;gap:48px}
  .hero-stats{position:static;margin-top:26px;justify-content:space-between}
}

/* ---------- 章节通用 ---------- */
.sec{padding:110px 0}
.sec-tight{padding:86px 0}
.sec-head{display:flex;align-items:flex-end;justify-content:space-between;gap:32px;margin-bottom:64px}
.sec-no{font-family:Georgia,serif;font-size:14px;color:var(--red);letter-spacing:3px;display:flex;align-items:center;gap:12px;margin-bottom:18px}
.sec-no::after{content:"";width:44px;height:1px;background:var(--red);opacity:.5}
.sec-head h2{font-family:var(--serif);font-weight:900;font-size:clamp(28px,3.6vw,42px);line-height:1.35;letter-spacing:1px}
.sec-head .sub{font-size:14.5px;color:var(--ink-2);max-width:30em}
.sec-head .sub-en{font-size:11px;color:var(--ink-3);letter-spacing:2px;text-transform:uppercase;margin-top:8px}
.dark{background:var(--dark);color:#E8E4E1}
.dark .sec-head h2{color:#F5F2EF}
.dark .sec-no{color:var(--red)}
.dark p{color:#B7B0AB}

/* ---------- 首页产品速览 ---------- */
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.grid-2{display:grid;grid-template-columns:repeat(2,1fr);gap:26px}
.grid-4{display:grid;grid-template-columns:repeat(4,1fr);gap:26px}
.card{
  background:var(--paper);border:1px solid var(--line);border-radius:3px;
  padding:34px 30px 30px;position:relative;transition:.22s;
}
.card:hover{transform:translateY(-4px);border-color:#CFC9C5;box-shadow:0 18px 36px rgba(28,27,26,.07)}
.card .c-no{font-family:Georgia,serif;font-size:13px;color:var(--ink-3);letter-spacing:2px}
.card h3{font-family:var(--serif);font-size:21px;margin:14px 0 4px;letter-spacing:.5px}
.card .c-en{font-size:11px;letter-spacing:1.5px;color:var(--red);text-transform:uppercase}
.card p{font-size:14px;color:var(--ink-2);margin-top:14px}
.card .c-line{width:30px;height:2px;background:var(--red);margin-top:18px;transition:.22s}
.card:hover .c-line{width:56px}
.ico{width:42px;height:42px;color:var(--red);margin-bottom:6px}

/* ---------- 钢材表 ---------- */
.tbl{width:100%;border-collapse:collapse;background:var(--paper);border:1px solid var(--line)}
.tbl th{
  font-size:13px;font-weight:600;letter-spacing:1px;text-align:left;color:var(--ink);
  background:#EFECEB;padding:15px 18px;border-bottom:2px solid var(--ink);
}
.tbl td{font-size:14px;padding:15px 18px;border-bottom:1px solid var(--line);vertical-align:top;color:var(--ink-2)}
.tbl tr:last-child td{border-bottom:none}
.tbl td b{color:var(--ink)}
.tbl .grade{font-family:Georgia,serif;color:var(--ink);font-weight:600;white-space:nowrap}
.tbl-wrap{overflow-x:auto}

/* ---------- 编号行文 ---------- */
.ed{display:grid;grid-template-columns:140px 1fr;gap:34px;padding:44px 0;border-top:1px solid var(--line)}
.ed:last-child{border-bottom:1px solid var(--line)}
.ed .ed-no{font-family:Georgia,serif;font-size:34px;color:var(--red);line-height:1}
.ed h3{font-family:var(--serif);font-size:23px;letter-spacing:.5px}
.ed .ed-en{font-size:11px;letter-spacing:2px;color:var(--ink-3);text-transform:uppercase;margin:4px 0 14px}
.ed p{font-size:15px;color:var(--ink-2);max-width:44em}
.ed .ed-tags{margin-top:14px;display:flex;gap:10px;flex-wrap:wrap}
.tag{font-size:12px;color:var(--ink-2);border:1px solid var(--line);background:var(--paper);padding:4px 12px;border-radius:99px}
.dark .ed{border-color:var(--dark-line)}
.dark .ed p{color:#B7B0AB}
.dark .tag{background:var(--dark-2);border-color:var(--dark-line);color:#C9C2BD}

/* ---------- 参数卡 ---------- */
.spec-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:26px;margin-top:52px}
.spec{
  background:var(--paper);border:1px solid var(--line);border-left:3px solid var(--red);
  border-radius:2px;padding:26px 28px;
}
.spec h4{font-family:var(--serif);font-size:17px;margin-bottom:10px}
.spec .v{font-family:Georgia,serif;font-size:24px;color:var(--ink);line-height:1.3}
.spec .v i{font-style:normal;font-size:13px;color:var(--ink-3);margin-left:4px}
.spec p{font-size:12.5px;color:var(--ink-3);margin-top:6px}

/* ---------- 数据带 ---------- */
.band{background:var(--red);color:#fff}
.band-in{display:grid;grid-template-columns:repeat(4,1fr);gap:24px;padding:64px 0}
.band div b{font-family:Georgia,serif;font-size:40px;line-height:1.15;display:block}
.band div b i{font-style:normal;font-size:18px;margin-left:2px;opacity:.85}
.band div span{font-size:13px;opacity:.9;letter-spacing:1px}
.band .src{grid-column:1/-1;font-size:11px;opacity:.75;border-top:1px solid rgba(255,255,255,.35);padding-top:14px}

/* ---------- 引用块 ---------- */
.quote{border-left:3px solid var(--red);padding:6px 0 6px 28px;margin:36px 0;font-family:var(--serif);font-size:19px;line-height:2;color:var(--ink)}
.quote small{display:block;font-family:var(--sans);font-size:12px;color:var(--ink-3);margin-top:10px;letter-spacing:1px}

/* ---------- 关键词区 ---------- */
.kw{background:var(--paper);border-top:1px solid var(--line);padding:40px 0}
.kw-in{display:flex;align-items:baseline;gap:22px;flex-wrap:wrap}
.kw b{font-size:13px;letter-spacing:3px;color:var(--ink-3);font-weight:600;white-space:nowrap}
.kw a{
  font-size:13.5px;color:var(--ink-2);border:1px solid var(--line);border-radius:99px;
  padding:6px 18px;transition:.2s;
}
.kw a:hover{color:#fff;background:var(--red);border-color:var(--red)}

/* ---------- 页脚 ---------- */
.site-foot{background:var(--dark);color:#A8A19B;padding:78px 0 0}
.foot-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:48px;padding-bottom:60px}
.foot-grid h4{color:#F0EDEA;font-size:14px;letter-spacing:2px;margin-bottom:20px;font-weight:600}
.foot-grid ul li{margin-bottom:11px;font-size:13.5px}
.foot-grid a:hover{color:var(--red)}
.foot-brand .logo-txt b{color:#F0EDEA}
.foot-brand p{font-size:13px;line-height:2;margin-top:18px;max-width:26em}
.foot-bar{border-top:1px solid var(--dark-line);padding:22px 0;display:flex;justify-content:space-between;gap:16px;flex-wrap:wrap;font-size:12px;color:#7A736E}

/* ---------- 页内导航 / 锚点 ---------- */
.anchor-list{display:flex;gap:12px;flex-wrap:wrap;margin:44px 0 8px}
.anchor-list a{font-size:13px;border:1px solid var(--line);background:var(--paper);padding:8px 20px;border-radius:2px;color:var(--ink-2);transition:.2s}
.anchor-list a:hover{border-color:var(--red);color:var(--red)}

/* ---------- 动效 ---------- */
@keyframes rise{from{opacity:0;transform:translateY(22px)}to{opacity:1;transform:none}}
.rise{animation:rise .7s ease both}
.rise.d1{animation-delay:.12s}.rise.d2{animation-delay:.24s}.rise.d3{animation-delay:.36s}
@media (prefers-reduced-motion:reduce){.rise{animation:none}}

/* ---------- 响应式 ---------- */
@media (max-width:980px){
  .grid-3,.grid-4{grid-template-columns:repeat(2,1fr)}
  .foot-grid{grid-template-columns:1fr 1fr}
  .band-in{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:640px){
  .grid-2,.grid-3,.grid-4,.spec-grid{grid-template-columns:1fr}
  .sec{padding:76px 0}
  .sec-head{flex-direction:column;align-items:flex-start;gap:18px;margin-bottom:44px}
  .ed{grid-template-columns:1fr;gap:12px;padding:32px 0}
  .hero-stats{flex-wrap:wrap;gap:18px 28px;padding:20px 22px}
  .hero-stats div b{font-size:22px}
  .foot-grid{grid-template-columns:1fr}
}