/* ============================================================
   庆阳市尧润通石油技术有限公司 - 企业官网
   主题色：深藏青 #163a63（呼应 logo 深藏青）+ 石油橙 #f0832a
   ============================================================ */
:root {
  --navy: #163a63;
  --navy-deep: #0e2a49;
  --navy-light: #1f4a7d;
  --accent: #f0832a;
  --accent-deep: #d96f17;
  --red: #d93b2d;
  --bg: #f4f6f9;
  --white: #ffffff;
  --text: #2b3442;
  --muted: #6b7686;
  --line: #e3e8ef;
  --radius: 10px;
  --shadow: 0 4px 20px rgba(14, 42, 73, .10);
  --shadow-lg: 0 12px 40px rgba(14, 42, 73, .16);
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--white);
  font-size: 15px;
  line-height: 1.75;
}
a { text-decoration: none; color: inherit; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
.container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* ---------------- 顶部信息条 ---------------- */
.topbar { background: var(--navy-deep); color: #cdd9e8; font-size: 13px; }
.topbar .container { display: flex; justify-content: space-between; align-items: center; min-height: 38px; flex-wrap: wrap; }
.topbar a { color: #cdd9e8; }
.topbar a:hover { color: var(--accent); }
.topbar .tb-left span { margin-right: 22px; }
.topbar .tb-left i { color: var(--accent); margin-right: 6px; font-style: normal; }
.topbar .tb-right a { margin-left: 18px; }

/* ---------------- 主头部 ---------------- */
.main-header { background: var(--navy); position: sticky; top: 0; z-index: 999; box-shadow: 0 2px 12px rgba(0,0,0,.18); }
.main-header .container { display: flex; align-items: center; justify-content: space-between; height: 78px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand img { height: 52px; width: auto; }
.brand .brand-txt { color: #fff; line-height: 1.25; }
.brand .brand-txt b { font-size: 20px; letter-spacing: 1px; display: block; }
.brand .brand-txt span { font-size: 12px; color: #9fb4cc; letter-spacing: 2px; }

.nav { display: flex; gap: 4px; }
.nav a { color: #e6edf5; padding: 10px 14px; font-size: 15px; border-radius: 6px; transition: .2s; position: relative; }
.nav a:hover, .nav a.active { color: #fff; background: rgba(255,255,255,.12); }
.nav a.active::after { content: ""; position: absolute; left: 14px; right: 14px; bottom: 4px; height: 2px; background: var(--accent); }

/* 移动端菜单按钮 */
.menu-btn { display: none; background: none; border: none; color: #fff; font-size: 24px; cursor: pointer; padding: 6px 10px; }

/* ---------------- 轮播 Banner ---------------- */
.banner { position: relative; height: 560px; overflow: hidden; background: var(--navy-deep); }
.banner .slide { position: absolute; inset: 0; opacity: 0; transition: opacity .8s; display: flex; align-items: center; }
.banner .slide.active { opacity: 1; z-index: 1; }
.banner .slide-inner { display: flex; align-items: center; justify-content: space-between; gap: 40px; width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 20px; position: relative; z-index: 2; }
.banner .slide-bg { position: absolute; inset: 0; background:
  radial-gradient(1200px 500px at 85% 20%, rgba(240,131,42,.18), transparent 60%),
  linear-gradient(120deg, #0a2140 0%, #14365f 55%, #1e4a80 100%); }
.banner h2 { color: #fff; font-size: 42px; line-height: 1.3; letter-spacing: 1px; margin-bottom: 16px; }
.banner h2 em { font-style: normal; color: var(--accent); }
.banner p { color: #c9d8e9; font-size: 16px; margin-bottom: 26px; max-width: 520px; }
.banner .btn { display: inline-block; padding: 12px 30px; border-radius: 6px; background: var(--accent); color: #fff; font-size: 15px; margin-right: 14px; transition: .2s; }
.banner .btn:hover { background: var(--accent-deep); }
.banner .btn.ghost { background: transparent; border: 1px solid rgba(255,255,255,.5); }
.banner .btn.ghost:hover { border-color: var(--accent); color: var(--accent); }
.banner .slide-img { width: 440px; flex: 0 0 440px; border-radius: 14px; overflow: hidden; box-shadow: 0 20px 50px rgba(0,0,0,.4); border: 1px solid rgba(255,255,255,.15); }
.banner .slide-img img { width: 100%; height: 320px; object-fit: cover; }
.banner-dots { position: absolute; bottom: 26px; left: 0; right: 0; z-index: 5; display: flex; justify-content: center; gap: 10px; }
.banner-dots span { width: 34px; height: 4px; border-radius: 2px; background: rgba(255,255,255,.35); cursor: pointer; transition: .3s; }
.banner-dots span.active { background: var(--accent); }

/* ---------------- 通用区块 ---------------- */
.section { padding: 72px 0; }
.section.bg { background: var(--bg); }
.sec-head { text-align: center; margin-bottom: 46px; }
.sec-head .en { font-size: 13px; letter-spacing: 4px; color: var(--accent); text-transform: uppercase; }
.sec-head h2 { font-size: 30px; color: var(--navy); margin: 8px 0 12px; }
.sec-head .bar { width: 56px; height: 3px; background: var(--accent); margin: 0 auto; border-radius: 2px; }
.sec-head p { color: var(--muted); margin-top: 12px; }

/* ---------------- 首页公司简介 ---------------- */
.intro { display: flex; gap: 50px; align-items: center; }
.intro .text { flex: 1; }
.intro .text h3 { color: var(--navy); font-size: 24px; margin-bottom: 16px; }
.intro .text p { color: #4a5568; margin-bottom: 14px; text-align: justify; }
.intro .stats { display: flex; gap: 30px; margin-top: 26px; }
.intro .stats .stat { flex: 1; background: var(--bg); border-radius: var(--radius); padding: 18px 10px; text-align: center; border-left: 3px solid var(--accent); }
.intro .stats .stat b { font-size: 28px; color: var(--navy); display: block; }
.intro .stats .stat span { font-size: 13px; color: var(--muted); }
.intro .media { flex: 0 0 460px; }
.intro .media .pic { border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }
.intro .media .pic img { height: 340px; width: 100%; object-fit: cover; }

/* ---------------- 产品卡片 ---------------- */
.grid { display: grid; gap: 26px; }
.grid.cols-2 { grid-template-columns: 1fr 1fr; }
.grid.cols-3 { grid-template-columns: repeat(3, 1fr); }
.grid.cols-4 { grid-template-columns: repeat(4, 1fr); }
.card { background: #fff; border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); transition: .25s; border: 1px solid var(--line); }
.card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.card .pic { overflow: hidden; }
.card .pic img { width: 100%; height: 220px; object-fit: cover; transition: .4s; }
.card:hover .pic img { transform: scale(1.06); }
.card .body { padding: 20px 22px 24px; }
.card .body h3 { font-size: 18px; color: var(--navy); margin-bottom: 8px; }
.card .body p { color: var(--muted); font-size: 14px; margin-bottom: 12px; height: 44px; overflow: hidden; }
.card .more { color: var(--accent); font-size: 14px; }
.card .more:hover { color: var(--accent-deep); }

/* ---------------- 特点/服务步骤 ---------------- */
.feature { text-align: center; background: #fff; border-radius: var(--radius); padding: 30px 20px; box-shadow: var(--shadow); border: 1px solid var(--line); }
.feature .icon { width: 66px; height: 66px; margin: 0 auto 16px; border-radius: 50%; background: linear-gradient(135deg, var(--navy), var(--navy-light)); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 26px; font-weight: bold; }
.feature h3 { font-size: 17px; color: var(--navy); margin-bottom: 8px; }
.feature p { font-size: 13px; color: var(--muted); }

/* ---------------- 数据/亮点条 ---------------- */
.highlight-band { background: linear-gradient(120deg, var(--navy-deep), var(--navy-light)); padding: 54px 0; }
.highlight-band .grid { grid-template-columns: repeat(4, 1fr); }
.hl { text-align: center; color: #fff; border-right: 1px solid rgba(255,255,255,.15); }
.hl:last-child { border-right: none; }
.hl b { font-size: 40px; color: var(--accent); display: block; line-height: 1.2; }
.hl span { font-size: 14px; color: #c9d8e9; }

/* ---------------- 图文模块（技术实力/案例） ---------------- */
.media-row { display: flex; gap: 40px; align-items: center; margin-bottom: 60px; }
.media-row.reverse { flex-direction: row-reverse; }
.media-row .pic { flex: 1; border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); border: 1px solid var(--line); }
.media-row .pic img { width: 100%; max-height: 420px; object-fit: cover; }
.media-row .txt { flex: 1; }
.media-row .txt h3 { font-size: 22px; color: var(--navy); margin-bottom: 12px; }
.media-row .txt h3 i { color: var(--accent); font-style: normal; margin-right: 8px; }
.media-row .txt p { color: #4a5568; margin-bottom: 10px; text-align: justify; }
.media-row .txt ul li { padding-left: 20px; position: relative; color: #4a5568; margin-bottom: 6px; font-size: 14px; }
.media-row .txt ul li::before { content: "◆"; color: var(--accent); position: absolute; left: 0; font-size: 10px; top: 5px; }

/* ---------------- 视频卡片 ---------------- */
.video-card { background: #fff; border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); border: 1px solid var(--line); }
.video-card .vid { position: relative; background: #000; }
.video-card video { width: 100%; height: 210px; object-fit: cover; }
.video-card .body { padding: 14px 18px; }
.video-card .body p { font-size: 14px; color: var(--text); }

/* ---------------- 联系我们 CTA ---------------- */
.cta { background: linear-gradient(120deg, var(--navy-deep), var(--navy)); color: #fff; text-align: center; padding: 56px 20px; }
.cta h2 { font-size: 28px; margin-bottom: 12px; }
.cta p { color: #c9d8e9; margin-bottom: 24px; }
.cta .btn { display: inline-block; background: var(--accent); color: #fff; padding: 13px 36px; border-radius: 6px; font-size: 16px; }
.cta .btn:hover { background: var(--accent-deep); }

/* ---------------- 页脚 ---------------- */
.footer { background: var(--navy-deep); color: #b9c8db; font-size: 13px; }
.footer .container { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 40px; padding: 48px 20px 36px; }
.footer h4 { color: #fff; font-size: 16px; margin-bottom: 16px; position: relative; padding-bottom: 10px; }
.footer h4::after { content: ""; position: absolute; left: 0; bottom: 0; width: 30px; height: 2px; background: var(--accent); }
.footer .f-brand img { height: 40px; margin-bottom: 14px; }
.footer .f-brand p { color: #8fa3bb; line-height: 2; }
.footer .f-links a { display: block; color: #b9c8db; padding: 4px 0; }
.footer .f-links a:hover { color: var(--accent); padding-left: 6px; transition: .2s; }
.footer .f-contact li { padding: 4px 0; }
.footer .f-contact li b { color: var(--accent); }
.footer .f-contact .phone { font-size: 22px; color: var(--accent); font-weight: bold; }
.copyright { border-top: 1px solid rgba(255,255,255,.1); padding: 16px 0; text-align: center; color: #7e93ab; font-size: 12px; }
.copyright a { color: #7e93ab; }
.copyright a:hover { color: var(--accent); }

/* ---------------- 内页 ---------------- */
.page-banner { background: linear-gradient(120deg, var(--navy-deep), var(--navy-light)); color: #fff; padding: 46px 0; }
.page-banner .container { display: flex; justify-content: space-between; align-items: center; }
.page-banner h2 { font-size: 28px; }
.page-banner .crumb { color: #9fb4cc; font-size: 13px; }
.page-banner .crumb a { color: var(--accent); }
.page-banner .crumb span { margin: 0 8px; }

/* 资质证书 */
.cert-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.cert { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 14px; box-shadow: var(--shadow); }
.cert img { border: 1px solid var(--line); border-radius: 6px; width: 100%; height: 260px; object-fit: contain; background: #fafbfc; }
.cert h4 { font-size: 14px; color: var(--navy); margin-top: 10px; text-align: center; }

/* 联系页 */
.contact-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: 40px; }
.contact-info .c-item { display: flex; gap: 16px; padding: 18px 0; border-bottom: 1px dashed var(--line); align-items: center; }
.contact-info .c-item:last-child { border-bottom: none; }
.contact-info .c-icon { width: 52px; height: 52px; flex: 0 0 52px; border-radius: 10px; background: linear-gradient(135deg, var(--navy), var(--navy-light)); color: #fff; display: flex; align-items: center; justify-content: center; font-size: 20px; }
.contact-info .c-item b { display: block; color: var(--navy); font-size: 16px; }
.contact-info .c-item span { color: var(--muted); font-size: 14px; }
.map-box { border-radius: var(--radius); overflow: hidden; border: 1px solid var(--line); min-height: 320px; background: #eef1f5; position: relative; }
.map-box .map-tip { position: absolute; inset: 0; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; color: var(--muted); }
.map-box .map-tip b { color: var(--navy); font-size: 16px; margin-bottom: 6px; }

/* 页内小工具 */
.panel { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 34px; margin-bottom: 34px; }
.panel h3 { color: var(--navy); font-size: 20px; margin-bottom: 14px; padding-left: 14px; border-left: 4px solid var(--accent); }
.panel p { color: #4a5568; margin-bottom: 10px; text-align: justify; }
.panel ul li { padding-left: 20px; position: relative; color: #4a5568; margin-bottom: 8px; }
.panel ul li::before { content: "◆"; color: var(--accent); position: absolute; left: 0; font-size: 10px; top: 6px; }
.panel table { width: 100%; border-collapse: collapse; margin-top: 8px; font-size: 14px; }
.panel table th, .panel table td { border: 1px solid var(--line); padding: 10px 12px; text-align: left; }
.panel table th { background: var(--bg); color: var(--navy); font-weight: 600; }
.panel table tr:nth-child(even) td { background: #fafbfc; }

/* 回到顶部 */
#toTop { position: fixed; right: 24px; bottom: 30px; width: 44px; height: 44px; background: var(--navy); color: #fff; border-radius: 8px; display: none; align-items: center; justify-content: center; cursor: pointer; z-index: 900; box-shadow: var(--shadow); border: none; font-size: 18px; }
#toTop.show { display: flex; }
#toTop:hover { background: var(--accent); }

/* ---------------- 响应式 ---------------- */
@media (max-width: 992px) {
  .banner { height: 440px; }
  .banner h2 { font-size: 30px; }
  .banner .slide-img { width: 320px; flex-basis: 320px; }
  .banner .slide-img img { height: 240px; }
  .grid.cols-4 { grid-template-columns: repeat(2, 1fr); }
  .grid.cols-3 { grid-template-columns: repeat(2, 1fr); }
  .cert-grid { grid-template-columns: repeat(2, 1fr); }
  .intro, .media-row, .media-row.reverse { flex-direction: column; }
  .intro .media { flex: none; width: 100%; }
  .contact-grid { grid-template-columns: 1fr; }
  .footer .container { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .menu-btn { display: block; }
  .nav { display: none; position: absolute; top: 78px; left: 0; right: 0; background: var(--navy); flex-direction: column; padding: 10px 20px 20px; }
  .nav.open { display: flex; }
  .nav a { padding: 12px 10px; border-bottom: 1px solid rgba(255,255,255,.08); }
  .topbar .tb-right { display: none; }
  .banner { height: 400px; }
  .banner .slide-inner { flex-direction: column; justify-content: center; text-align: center; gap: 20px; }
  .banner .slide-img { display: none; }
  .banner h2 { font-size: 24px; }
  .banner p { font-size: 14px; }
  .brand .brand-txt span { display: none; }
  .grid.cols-2, .grid.cols-3, .grid.cols-4 { grid-template-columns: 1fr; }
  .highlight-band .grid { grid-template-columns: repeat(2, 1fr); gap: 26px; }
  .hl { border-right: none; }
  .cert-grid { grid-template-columns: 1fr; }
  .section { padding: 48px 0; }
  .footer .container { grid-template-columns: 1fr; }
  .intro .stats { flex-direction: column; }
}