/* ============================================================
   靖江市三一零金属科技有限公司 — 官网改版样式
   现代工业风 · 深蓝 + 钢灰 · 响应式（PC / 平板 / 手机）
   ============================================================ */
:root {
  --blue-900: #0d2b4e;
  --blue-800: #123c6b;
  --blue-700: #17529b;
  --blue-600: #1a63b8;
  --blue-500: #2180d9;
  --steel-600: #64748b;
  --steel-400: #94a3b8;
  --steel-100: #e8edf3;
  --bg: #f4f6f9;
  --card: #ffffff;
  --ink: #1f2937;
  --ink-soft: #4b5563;
  --line: #dde4ec;
  --accent: #f97316;
  --accent-dark: #ea580c;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(15, 35, 66, .08), 0 6px 18px rgba(15, 35, 66, .06);
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html { -webkit-text-size-adjust: 100%; }
body {
  font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "Segoe UI", system-ui, sans-serif;
  color: var(--ink);
  background: var(--bg);
  font-size: 16px;
  line-height: 1.75;
}
a { color: var(--blue-700); text-decoration: none; }
a:hover { color: var(--blue-500); }
img { max-width: 100%; height: auto; display: block; }

/* ---------- 顶部信息条 ---------- */
.topbar {
  background: var(--blue-900);
  color: #c9d8ea;
  font-size: 13.5px;
}
.topbar-in {
  max-width: 1280px; margin: 0 auto; padding: 7px 20px;
  display: flex; flex-wrap: wrap; gap: 8px 26px; align-items: center; justify-content: flex-end;
}
.topbar a { color: #ffd9b3; }
.topbar .wx { color: #fff; font-weight: 600; }

/* ---------- 主头部 ---------- */
/* ---------- 主头部：图衬字上（铺满全宽） ---------- */
.masthead { position: relative; }
.banner-box { position: relative; width: 100%; height: 260px; overflow: hidden; }
.banner-box .banner {
  position: absolute; left: 0; top: 0; width: 100%; height: 100%;
  object-fit: cover; object-position: center 35%;
}
.banner-box .masthead-in {
  position: absolute; left: 0; top: 0; right: 0; bottom: 0;
  display: flex; flex-direction: column; justify-content: center;
  max-width: 1280px; margin: 0 auto; padding: 10px 20px;
  color: #fff;
  text-shadow: 0 2px 10px rgba(0,0,0,.7), 0 0 3px rgba(0,0,0,.85);
}
.masthead .cn {
  font-size: clamp(22px, 2.6vw, 30px);
  font-weight: 800; letter-spacing: 2px;
}
.masthead .en {
  font-size: 13px; letter-spacing: 3px; color: #e0ecf9;
  margin-top: 6px; text-transform: uppercase;
}
.masthead .tag {
  display: inline-block; margin-top: 14px; padding: 5px 14px;
  border-left: 4px solid var(--accent);
  background: rgba(255,255,255,.10);
  font-size: 15px; color: #f3f7fc;
}

/* ---------- 主导航 ---------- */
.mainnav { background: var(--blue-800); position: sticky; top: 0; z-index: 50; box-shadow: var(--shadow); }
.nav-in { max-width: 1280px; margin: 0 auto; padding: 0 20px; display: flex; align-items: center; gap: 4px; flex-wrap: wrap; }
.nav-toggle { display: none; }
.nav-toggle-btn {
  display: none; color: #fff; font-size: 17px; cursor: pointer;
  padding: 14px 20px; user-select: none; max-width: 1280px; margin: 0 auto;
}
.mainnav a.navlink {
  color: #e6eefb; padding: 15px 18px; font-size: 16px; font-weight: 500;
  display: inline-block; border-bottom: 3px solid transparent; transition: all .15s;
}
.mainnav a.navlink:hover { background: var(--blue-700); color: #fff; }
.mainnav a.navlink.active { background: var(--blue-700); color: #fff; border-bottom-color: var(--accent); }

/* ---------- 布局 ---------- */
.container {
  max-width: 1280px; margin: 26px auto 40px; padding: 0 20px;
  display: grid; grid-template-columns: 292px minmax(0, 1fr); gap: 24px; align-items: start;
}
@media (max-width: 960px) {
  .container { grid-template-columns: 1fr; margin-top: 16px; }
}

/* ---------- 侧边栏产品导航 ---------- */
.sidebar { position: sticky; top: 64px; }
@media (max-width: 960px) { .sidebar { position: static; } }
.sidebar .box {
  background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow);
  margin-bottom: 18px; overflow: hidden;
}
.sidebar .box-title {
  background: linear-gradient(135deg, var(--blue-800), var(--blue-600));
  color: #fff; font-size: 16px; font-weight: 700;
  padding: 12px 18px; letter-spacing: 1px;
}
.sidebar .box-title::before { content: "▍"; color: var(--accent); margin-right: 6px; }
.cat { border-bottom: 1px solid var(--line); }
.cat:last-child { border-bottom: 0; }
.cat > summary {
  list-style: none; cursor: pointer; user-select: none;
  padding: 11px 18px; font-weight: 600; font-size: 15px; color: var(--blue-800);
  background: #f7fafd; display: flex; justify-content: space-between; align-items: center;
}
.cat > summary::-webkit-details-marker { display: none; }
.cat > summary::after { content: "＋"; color: var(--steel-400); font-size: 14px; transition: transform .15s; }
.cat[open] > summary::after { content: "－"; }
.cat > summary:hover { background: #eef4fb; }
.cat ul { list-style: none; padding: 4px 0 8px; }
.cat li a {
  display: block; padding: 7px 18px 7px 30px; font-size: 14.5px; color: var(--ink-soft);
  border-left: 3px solid transparent;
}
.cat li a::before { content: "· "; color: var(--steel-400); }
.cat li a:hover { color: var(--blue-700); background: #f2f7fd; }
.cat li a.active { color: var(--blue-700); font-weight: 700; border-left-color: var(--accent); background: #eef4fb; }

.contact-mini { padding: 14px 18px; font-size: 14px; color: var(--ink-soft); }
.contact-mini strong { color: var(--blue-800); display: block; margin-bottom: 6px; font-size: 15px; }
.contact-mini .tel { font-size: 19px; font-weight: 800; color: var(--blue-700); letter-spacing: 1px; }

/* ---------- 主内容区 ---------- */
.content { min-width: 0; }
.page-head {
  background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 20px 26px; margin-bottom: 20px;
  border-top: 4px solid var(--blue-600);
}
.page-head h1 { font-size: clamp(20px, 2.4vw, 26px); color: var(--blue-900); font-weight: 800; letter-spacing: 1px; }
.crumb { margin-top: 8px; font-size: 13px; color: var(--steel-600); }
.crumb a { color: var(--steel-600); }
.crumb a:hover { color: var(--blue-700); }

.section {
  background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 26px 28px; margin-bottom: 22px;
}
.section-title {
  font-size: 19px; color: var(--blue-800); font-weight: 700;
  padding-bottom: 12px; margin-bottom: 18px;
  border-bottom: 2px solid var(--steel-100);
  display: flex; align-items: center; gap: 10px;
}
.section-title::before {
  content: ""; width: 5px; height: 20px; border-radius: 3px;
  background: linear-gradient(180deg, var(--blue-500), var(--blue-700));
  flex: 0 0 auto;
}

/* 正文排版 */
.section p, .section .prose { font-size: 15.5px; color: var(--ink-soft); margin: 10px 0; text-align: justify; }
.section strong { color: var(--ink); }
.section .hl { color: #d9480f; font-weight: 700; }
.section h2, .section h3 { color: var(--blue-900); margin: 18px 0 8px; font-size: 18px; }

/* 产品图片网格 */
.gallery {
  display: grid; gap: 18px; margin: 18px 0;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
}
.gallery figure {
  background: #fff; border: 1px solid var(--line); border-radius: 8px;
  overflow: hidden; box-shadow: 0 1px 2px rgba(15,35,66,.06);
  transition: box-shadow .18s, transform .18s;
  display: flex; flex-direction: column;
}
.gallery figure:hover { box-shadow: 0 8px 22px rgba(15,35,66,.14); transform: translateY(-2px); }
.gallery figure > a { display: block; }
.gallery img {
  width: 100%; aspect-ratio: 4 / 3.3; object-fit: cover; background: #f1f4f8;
}
.gallery figcaption {
  padding: 9px 12px; font-size: 13.5px; color: var(--ink-soft); text-align: center;
  background: #f8fafc; border-top: 1px solid var(--line); line-height: 1.5;
}

/* 规格参数表 */
.table-wrap { overflow-x: auto; margin: 18px 0; border-radius: 8px; border: 1px solid var(--line); }
table.data {
  width: 100%; border-collapse: collapse; font-size: 14.5px; background: #fff;
  min-width: 420px;
}
table.data th, table.data td {
  border: 1px solid var(--line); padding: 9px 14px; text-align: center; color: var(--ink-soft);
}
table.data th { background: #eef4fb; color: var(--blue-800); font-weight: 700; white-space: nowrap; }
table.data tr:nth-child(even) td { background: #fafcfe; }

/* 首页：快捷入口 */
.quickcards { display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 18px; margin: 26px 0; }
.qcard {
  background: linear-gradient(135deg, var(--blue-800), var(--blue-600));
  color: #fff; border-radius: var(--radius); padding: 26px 24px;
  display: flex; flex-direction: column; gap: 4px; position: relative; overflow: hidden;
  box-shadow: var(--shadow); transition: transform .18s, box-shadow .18s;
}
.qcard:nth-child(even) { background: linear-gradient(135deg, #243447, #3d5875); }
.qcard:hover { transform: translateY(-3px); box-shadow: 0 10px 26px rgba(15,35,66,.18); }
.qcard::after {
  content: "→"; position: absolute; right: 18px; bottom: 14px; font-size: 22px; opacity: .55;
}
.qcard .t { font-size: 20px; font-weight: 800; letter-spacing: 1px; }
.qcard .s { font-size: 12.5px; color: #cfe0f2; letter-spacing: 1px; }

/* 首页：特点条 */
.stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin: 22px 0;
}
.stat {
  background: var(--card); border-radius: var(--radius); box-shadow: var(--shadow);
  padding: 18px 20px; border-bottom: 3px solid var(--blue-600); text-align: center;
}
.stat .n { font-size: 22px; font-weight: 800; color: var(--blue-700); }
.stat .l { font-size: 13px; color: var(--steel-600); margin-top: 3px; }

/* 流程图 */
.flowchart img { margin: 0 auto; border-radius: 8px; box-shadow: var(--shadow); }

/* ---------- 页脚 ---------- */
.sitefoot { background: var(--blue-900); color: #b7c9dd; margin-top: 30px; }
.foot-in {
  max-width: 1280px; margin: 0 auto; padding: 34px 20px 26px;
  display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 28px; font-size: 14px;
}
@media (max-width: 860px) { .foot-in { grid-template-columns: 1fr; } }
.foot-in h4 { color: #fff; font-size: 15px; margin-bottom: 12px; letter-spacing: 1px; }
.foot-in h4::after { content: ""; display: block; width: 26px; height: 3px; background: var(--accent); margin-top: 6px; border-radius: 2px; }
.foot-in a { color: #cfe0f2; }
.foot-in a:hover { color: #fff; }
.foot-in .tel { font-size: 21px; font-weight: 800; color: #fff; letter-spacing: 1px; }
.icp {
  border-top: 1px solid rgba(255,255,255,.14);
  text-align: center; padding: 16px 20px 20px; font-size: 13px; color: #8ba3bf;
}
.icp img { margin: 10px auto 0; width: 50px; height: 50px; border-radius: 4px; }

/* ---------- 移动端 ---------- */
@media (max-width: 860px) {
  .nav-toggle-btn { display: block; }
  .nav-in { display: none; padding: 6px 12px 12px; }
  .nav-toggle:checked ~ .nav-in { display: flex; flex-direction: column; align-items: stretch; }
  .mainnav a.navlink { border-bottom: 1px solid rgba(255,255,255,.08); padding: 12px 18px; }
  .section { padding: 18px 16px; }
  .page-head { padding: 16px 18px; }
  .gallery { grid-template-columns: repeat(auto-fill, minmax(160px, 1fr)); gap: 12px; }
  .banner-box { height: 190px; }
  .banner-box .masthead-in { max-width: 64%; padding: 8px 20px; }
}