/* ============================================================
   SA203GrD 钢板专题站 —— 工业实用风
   主色 #3b75bc (60%) / 辅色 #ec5029 (30%) / 点缀 #f7d260 (10%)
   线性图标（SVG stroke）、移动端优先、锐利工业感
   ============================================================ */
:root {
  --c1: #3b75bc;        /* 主色调 */
  --c1-deep: #27517f;   /* 主色加深 */
  --c1-dark: #1d3f63;   /* 深蓝底 */
  --c1-ink: #22334a;    /* 正文墨色 */
  --c1-pale: #eef4fa;   /* 主色浅底 */
  --c1-line: #d5e2ef;   /* 主色浅线 */
  --c2: #ec5029;        /* 辅助色 */
  --c2-deep: #c43f1e;
  --c3: #f7d260;        /* 点缀色 */
  --c3-pale: #fdf6e0;
  --c4: #f7f9fb;        /* 页面底色 */
  --white: #ffffff;
  --gray: #5d6f83;
  --radius: 6px;
  --mono: "JetBrains Mono", Consolas, "Courier New", monospace;
  --sans: "Noto Sans SC", "Source Han Sans SC", "Microsoft YaHei", "PingFang SC", sans-serif;
  --shadow: 0 2px 10px rgba(39, 81, 127, 0.10);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  color: var(--c1-ink);
  background: var(--c4);
  line-height: 1.75;
  font-size: 16px;
}
img, svg { vertical-align: middle; }
a { color: var(--c1); text-decoration: none; }
a:hover { color: var(--c2); text-decoration: underline; }

/* ---------- 顶部条 ---------- */
.topbar { background: var(--c1-dark); color: #cfe0f2; font-size: 13px; }
.topbar .wrap {
  max-width: 1120px; margin: 0 auto; padding: 6px 20px;
  display: flex; justify-content: space-between; align-items: center; gap: 12px; flex-wrap: wrap;
}
.topbar a { color: var(--c3); font-family: var(--mono); font-weight: 700; }
.topbar a:hover { color: var(--white); }

/* ---------- 页头导航 ---------- */
.site-header {
  background: var(--white);
  border-top: 3px solid var(--c2);
  box-shadow: var(--shadow);
  position: sticky; top: 0; z-index: 50;
}
.nav-wrap {
  max-width: 1120px; margin: 0 auto; padding: 0 20px;
  display: flex; align-items: center; justify-content: space-between; height: 62px;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand-mark {
  width: 38px; height: 38px; background: var(--c1); border-radius: 4px;
  display: flex; align-items: center; justify-content: center; flex: none;
}
.brand-mark svg { stroke: var(--white); }
.brand-text { line-height: 1.15; }
.brand-text b { display: block; color: var(--c1-deep); font-size: 18px; letter-spacing: 0.5px; }
.brand-text span { display: block; font-size: 11px; color: var(--gray); font-family: var(--mono); }

.nav-links { display: flex; gap: 0; list-style: none; }
.nav-links a {
  display: block; padding: 8px 9px; color: var(--c1-ink); font-size: 14px; font-weight: 500;
  white-space: nowrap;
  border-bottom: 3px solid transparent; transition: border-color 0.2s, color 0.2s;
}
.nav-links a:hover { color: var(--c1); text-decoration: none; }
.nav-links a.active { color: var(--c1); border-bottom-color: var(--c2); font-weight: 700; }
.nav-toggle { display: none; background: none; border: 2px solid var(--c1); border-radius: 4px; padding: 6px 8px; cursor: pointer; }
.nav-toggle svg { stroke: var(--c1); display: block; }

/* ---------- 面包屑 ---------- */
.crumbs { background: var(--c1-pale); border-bottom: 1px solid var(--c1-line); font-size: 13px; }
.crumbs .wrap { max-width: 1120px; margin: 0 auto; padding: 8px 20px; color: var(--gray); }
.crumbs a { color: var(--c1-deep); }
.crumbs .sep { margin: 0 6px; color: var(--c1-line); }

/* ---------- Hero ---------- */
.hero { background: linear-gradient(135deg, var(--c1-dark) 0%, var(--c1) 70%, #4a83c9 100%); color: var(--white); position: relative; overflow: hidden; }
.hero::after {
  content: ""; position: absolute; inset: 0; pointer-events: none;
  background:
    repeating-linear-gradient(90deg, rgba(255,255,255,0.045) 0 1px, transparent 1px 90px),
    repeating-linear-gradient(0deg, rgba(255,255,255,0.03) 0 1px, transparent 1px 90px);
}
.hero .wrap { max-width: 1120px; margin: 0 auto; padding: 54px 20px 46px; position: relative; z-index: 1; }
.hero .kicker {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(236, 80, 41, 0.18); border: 1px solid var(--c2); color: #ffd9cd;
  font-size: 13px; padding: 3px 12px; border-radius: 999px; font-family: var(--mono);
}
.hero .grade-code {
  font-family: var(--mono); font-weight: 800; letter-spacing: 1px;
  font-size: clamp(40px, 7vw, 64px); line-height: 1.15; margin: 14px 0 6px;
  text-shadow: 0 2px 0 rgba(0,0,0,0.15);
}
.hero .grade-code .g { color: var(--c3); }
.hero h1 { font-size: clamp(20px, 3vw, 26px); font-weight: 600; color: #eaf3fb; }
.hero .hero-en { font-size: 14px; color: #b9d2ea; font-family: var(--mono); margin-top: 6px; word-break: break-word; overflow-wrap: anywhere; }
.hero .hero-lead { margin-top: 16px; font-size: 16px; color: #dcebfa; max-width: 720px; }
.hero-stats { display: flex; gap: 14px; margin-top: 26px; flex-wrap: wrap; }
.hstat {
  background: rgba(255,255,255,0.10); border: 1px solid rgba(255,255,255,0.25);
  border-left: 4px solid var(--c3); padding: 10px 16px; min-width: 150px; border-radius: 4px;
}
.hstat .v { font-family: var(--mono); font-weight: 800; font-size: 20px; color: var(--c3); }
.hstat .k { font-size: 12px; color: #c9ddef; margin-top: 2px; }

/* ---------- 版式骨架 ---------- */
.wrap { max-width: 1120px; margin: 0 auto; padding: 0 20px; }
main.wrap { padding-top: 40px; padding-bottom: 30px; }
.section { margin-bottom: 44px; }
.sec-head { display: flex; align-items: baseline; gap: 12px; border-left: 6px solid var(--c2); padding-left: 14px; margin-bottom: 18px; }
.sec-head .no { font-family: var(--mono); font-weight: 800; color: var(--c2); font-size: 15px; }
.sec-head h2 { font-size: 24px; color: var(--c1-deep); letter-spacing: 0.5px; }
.sec-head .en { font-size: 12px; color: var(--gray); font-family: var(--mono); }
h3.sub { font-size: 19px; color: var(--c1-deep); margin: 26px 0 10px; padding-left: 10px; border-left: 4px solid var(--c3); }
p { margin: 10px 0; color: var(--c1-ink); }
.lead { font-size: 17px; color: var(--c1-deep); font-weight: 500; }
.muted { color: var(--gray); font-size: 14px; }
strong { color: var(--c1-deep); }

/* ---------- 卡片网格 ---------- */
.grid { display: grid; gap: 16px; }
.grid.c2 { grid-template-columns: repeat(2, 1fr); }
.grid.c3 { grid-template-columns: repeat(3, 1fr); }
.grid.c4 { grid-template-columns: repeat(4, 1fr); }
.card {
  background: var(--white); border: 1px solid var(--c1-line); border-radius: var(--radius);
  border-top: 4px solid var(--c1); padding: 18px 18px 14px; box-shadow: var(--shadow);
}
.card.warm { border-top-color: var(--c2); }
.card h4 { font-size: 17px; color: var(--c1-deep); margin-bottom: 8px; display: flex; align-items: center; gap: 8px; }
.card h4 svg { stroke: var(--c2); flex: none; }
.card p { font-size: 14px; color: var(--gray); margin: 6px 0; }
.card .big { font-family: var(--mono); font-weight: 800; font-size: 22px; color: var(--c2); }

/* ---------- 数据速览 ---------- */
.data-strip { display: grid; grid-template-columns: repeat(5, 1fr); gap: 12px; }
.dcell { background: var(--white); border: 1px solid var(--c1-line); border-radius: var(--radius); padding: 14px 10px; text-align: center; }
.dcell .v { font-family: var(--mono); font-weight: 800; font-size: 19px; color: var(--c1); }
.dcell .v em { color: var(--c2); font-style: normal; }
.dcell .k { font-size: 12px; color: var(--gray); margin-top: 4px; }

/* ---------- 表格 ---------- */
.tbl-scroll { overflow-x: auto; border: 1px solid var(--c1-line); border-radius: var(--radius); background: var(--white); box-shadow: var(--shadow); }
table { width: 100%; border-collapse: collapse; font-size: 14.5px; min-width: 560px; }
caption { text-align: left; padding: 12px 16px 0; font-size: 13px; color: var(--gray); caption-side: top; }
th, td { padding: 10px 14px; text-align: center; border-bottom: 1px solid var(--c1-line); }
thead th { background: var(--c1); color: var(--white); font-weight: 600; white-space: nowrap; }
tbody tr:nth-child(even) { background: var(--c1-pale); }
tbody tr:last-child td { border-bottom: none; }
td.num, th.num { font-family: var(--mono); }
td.hl { color: var(--c2); font-weight: 700; }
table.notes td, table.notes th { text-align: left; }

/* ---------- 提示框 ---------- */
.note {
  background: var(--c3-pale); border: 1px solid var(--c3); border-left: 5px solid var(--c3);
  border-radius: var(--radius); padding: 12px 16px; font-size: 14px; margin: 14px 0;
}
.note b { color: var(--c1-deep); }
.danger { background: #fdeee9; border-color: var(--c2); border-left-color: var(--c2); }
.info { background: var(--c1-pale); border-color: var(--c1-line); border-left-color: var(--c1); }

/* ---------- 列表 ---------- */
ul.tick { list-style: none; margin: 10px 0; }
ul.tick li { padding: 6px 0 6px 26px; position: relative; }
ul.tick li::before {
  content: ""; position: absolute; left: 2px; top: 13px;
  width: 14px; height: 8px; border-left: 3px solid var(--c2); border-bottom: 3px solid var(--c2);
  transform: rotate(-45deg);
}
ol.steps { counter-reset: step; list-style: none; margin: 12px 0; }
ol.steps li { counter-increment: step; padding: 8px 0 8px 44px; position: relative; }
ol.steps li::before {
  content: counter(step); position: absolute; left: 0; top: 8px;
  width: 28px; height: 28px; background: var(--c1); color: var(--white);
  font-family: var(--mono); font-weight: 800; display: flex; align-items: center; justify-content: center;
  border-radius: 4px; font-size: 14px;
}

/* ---------- FAQ ---------- */
.faq-item { background: var(--white); border: 1px solid var(--c1-line); border-left: 5px solid var(--c1); border-radius: var(--radius); margin-bottom: 12px; padding: 14px 18px; }
.faq-item .q { font-weight: 700; color: var(--c1-deep); display: flex; gap: 10px; align-items: baseline; }
.faq-item .q::before { content: "Q"; font-family: var(--mono); color: var(--c2); font-weight: 800; flex: none; }
.faq-item .a { margin-top: 8px; color: var(--c1-ink); font-size: 15px; }
.faq-item .a::before { content: "A："; font-family: var(--mono); color: var(--c1); font-weight: 700; }

/* ---------- 对照卡 ---------- */
.duo { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; align-items: stretch; }
.lang-en {
  background: var(--c1-pale); border: 1px dashed var(--c1); border-radius: var(--radius);
  padding: 12px 16px; font-size: 14px; color: var(--c1-deep);
}
.lang-en .tag { display: inline-block; background: var(--c1); color: var(--white); font-size: 11px; font-family: var(--mono); padding: 1px 8px; border-radius: 3px; margin-bottom: 6px; }

/* ---------- 关键词区 ---------- */
.keywords {
  background: var(--white); border: 1px solid var(--c1-line); border-radius: var(--radius);
  padding: 16px 20px; margin: 34px 0 10px; border-top: 4px solid var(--c3);
}
.keywords .kw-title { font-size: 13px; color: var(--gray); font-weight: 600; margin-bottom: 10px; display: flex; align-items: center; gap: 8px; }
.keywords .kw-title svg { stroke: var(--c2); }
.kw-list { display: flex; flex-wrap: wrap; gap: 10px; list-style: none; }
.kw-list a {
  display: inline-flex; align-items: center; gap: 6px;
  background: var(--c1-pale); color: var(--c1-deep); font-size: 13.5px;
  padding: 5px 14px; border-radius: 999px; border: 1px solid var(--c1-line);
  transition: all 0.2s;
}
.kw-list a::before { content: "#"; font-family: var(--mono); color: var(--c2); font-weight: 800; }
.kw-list a:hover { background: var(--c1); color: var(--white); text-decoration: none; border-color: var(--c1); }

/* ---------- 页脚 ---------- */
.site-footer { background: var(--c1-dark); color: #b9cfe4; margin-top: 40px; }
.footer-cta { background: var(--c2); color: var(--white); }
.footer-cta .wrap { display: flex; align-items: center; justify-content: space-between; gap: 14px; padding-top: 18px; padding-bottom: 18px; flex-wrap: wrap; }
.footer-cta .cta-text { font-size: 17px; font-weight: 700; }
.footer-cta .cta-tel { display: flex; align-items: center; gap: 10px; font-family: var(--mono); font-size: 24px; font-weight: 800; color: var(--c3); letter-spacing: 1px; }
.footer-cta .cta-tel svg { stroke: var(--c3); }
.footer-main { max-width: 1120px; margin: 0 auto; padding: 28px 20px 10px; display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 24px; }
.footer-main h5 { color: var(--white); font-size: 15px; margin-bottom: 10px; padding-bottom: 6px; border-bottom: 1px solid rgba(255,255,255,0.15); }
.footer-main ul { list-style: none; font-size: 13.5px; }
.footer-main li { margin: 5px 0; }
.footer-main a { color: #b9cfe4; }
.footer-main a:hover { color: var(--c3); }
.footer-base { max-width: 1120px; margin: 0 auto; padding: 14px 20px 22px; font-size: 12px; color: #7f9dbb; border-top: 1px solid rgba(255,255,255,0.12); }

/* ---------- 图标通用 ---------- */
.ic { width: 20px; height: 20px; stroke-width: 2; fill: none; stroke-linecap: round; stroke-linejoin: round; }
.ic-lg { width: 26px; height: 26px; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .grid.c3, .grid.c4 { grid-template-columns: repeat(2, 1fr); }
  .data-strip { grid-template-columns: repeat(2, 1fr); }
  .footer-main { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  body { font-size: 15px; }
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute; top: 65px; left: 0; right: 0;
    background: var(--white); flex-direction: column; border-bottom: 3px solid var(--c2);
    box-shadow: var(--shadow); padding: 8px 16px 14px;
  }
  .nav-links.open { display: flex; }
  .nav-links a { border-bottom: 1px solid var(--c1-line); padding: 12px 4px; }
  .nav-links a.active { border-bottom-color: var(--c1-line); }
  .grid.c2, .grid.c3, .grid.c4 { grid-template-columns: 1fr; }
  .duo { grid-template-columns: 1fr; }
  .data-strip { grid-template-columns: repeat(2, 1fr); }
  .footer-main { grid-template-columns: 1fr; }
  .hero .wrap { padding: 36px 20px 32px; }
  .footer-cta .cta-tel { font-size: 20px; }
  .sec-head h2 { font-size: 20px; }
  table { font-size: 13.5px; }
}