/* 北京泰普讯官网样式 - 基础与移动端（移动优先） */
:root {
    --primary: #c8161d; --primary-dark: #a01218; --dark: #1f2329;
    --gray-1: #f5f6f8; --gray-2: #e8eaee; --gray-3: #9aa0a8;
    --text: #333a45; --text-light: #6b7280; --white: #fff;
    --radius: 8px; --shadow: 0 4px 16px rgba(15,23,42,.08);
    --shadow-lg: 0 12px 32px rgba(15,23,42,.14);
    --header-h: 64px; --container: 1200px;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
    font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    color: var(--text); line-height: 1.7; background: var(--white); overflow-x: hidden;
}
img { max-width: 100%; display: block; border: 0; }
a { color: inherit; text-decoration: none; transition: color .2s; }
button { font-family: inherit; cursor: pointer; border: 0; background: none; }
.container { width: 100%; max-width: var(--container); margin: 0 auto; padding: 0 20px; }
.skip-link { position: absolute; left: -9999px; top: 0; z-index: 999; background: var(--primary); color: #fff; padding: 8px 16px; }
.skip-link:focus { left: 0; }

/* 通用 */
.section { padding: 56px 0; }
.section-head { text-align: center; margin-bottom: 36px; }
.section-head.left { text-align: left; }
.section-title { font-size: 26px; color: var(--dark); letter-spacing: 2px; display: inline-block; }
.section-title::after { content: ""; display: block; width: 42px; height: 3px; background: var(--primary); margin: 10px auto 0; border-radius: 2px; }
.section-en { color: var(--gray-3); font-size: 14px; letter-spacing: 4px; margin-top: 8px; text-transform: uppercase; }
.section-more { text-align: center; margin-top: 32px; }
.accent-title { color: var(--primary); font-size: 26px; margin-bottom: 18px; letter-spacing: 1px; }
.btn { display: inline-block; padding: 11px 34px; border-radius: 999px; font-size: 15px; letter-spacing: 1px; transition: all .25s; border: 1px solid transparent; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); color: #fff; }
.btn-outline { border-color: var(--primary); color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: #fff; }
.btn-outline-light { border-color: rgba(255,255,255,.7); color: #fff; }
.btn-outline-light:hover { background: #fff; color: var(--primary); }
.btn-light { background: #fff; color: var(--primary); }
.btn-light:hover { background: var(--primary); color: #fff; }
.empty-tip { color: var(--gray-3); text-align: center; padding: 60px 0; }

/* 头部 */
.site-header { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,.96); backdrop-filter: blur(8px); box-shadow: 0 1px 0 var(--gray-2); transition: box-shadow .3s; }
.site-header.scrolled { box-shadow: 0 4px 16px rgba(0,0,0,.08); }
.header-inner { display: flex; align-items: center; justify-content: space-between; height: var(--header-h); }
.logo img { height: 38px; width: auto; }
.main-nav { display: none; }
.nav-list { display: flex; gap: 4px; list-style: none; }
.nav-item { position: relative; }
.nav-item > a { display: block; padding: 8px 16px; font-size: 16px; color: var(--dark); letter-spacing: 1px; border-radius: var(--radius); }
.nav-item > a:hover, .nav-item.active > a { color: var(--primary); }
.nav-item.active > a::after { content: ""; position: absolute; left: 16px; right: 16px; bottom: -2px; height: 2px; background: var(--primary); border-radius: 1px; }
.dropdown { position: absolute; top: 100%; left: 0; min-width: 150px; background: #fff; border-radius: var(--radius); box-shadow: var(--shadow-lg); padding: 6px; opacity: 0; visibility: hidden; transform: translateY(8px); transition: all .25s; list-style: none; z-index: 50; }
.nav-item:hover .dropdown { opacity: 1; visibility: visible; transform: translateY(0); }
.dropdown a { display: block; padding: 9px 14px; font-size: 14px; color: var(--text); border-radius: 6px; white-space: nowrap; }
.dropdown a:hover { background: var(--gray-1); color: var(--primary); }
.header-actions { display: flex; align-items: center; gap: 16px; }
.header-tel { display: none; text-align: right; line-height: 1.3; }
.tel-label { display: block; font-size: 11px; color: var(--gray-3); }
.tel-num { display: block; font-size: 17px; font-weight: 700; color: var(--primary); letter-spacing: .5px; }
.nav-toggle { display: flex; flex-direction: column; gap: 5px; padding: 10px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--dark); border-radius: 2px; transition: all .3s; }
.nav-toggle.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle.open span:nth-child(2) { opacity: 0; }
.nav-toggle.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* 移动端抽屉导航 */
.mobile-nav { position: fixed; inset: 0; top: var(--header-h); background: #fff; transform: translateX(100%); transition: transform .3s ease; overflow-y: auto; z-index: 99; padding: 12px 20px 40px; }
.mobile-nav.open { transform: translateX(0); }
.mobile-nav > ul { list-style: none; }
.mobile-nav > ul > li > a { display: block; padding: 14px 4px; font-size: 17px; color: var(--dark); border-bottom: 1px solid var(--gray-2); }
.mobile-sub { list-style: none; padding-left: 16px; }
.mobile-sub a { display: block; padding: 10px 4px; color: var(--text-light); border-bottom: 1px dashed var(--gray-2); font-size: 15px; }

/* 首页轮播 */
.hero { position: relative; overflow: hidden; background: #0e1116; }
.hero-slider { position: relative; }
.hero-track { display: flex; transition: transform .6s ease; }
.hero-slide { flex: 0 0 100%; }
.hero-slide img { width: 100%; height: 62vh; min-height: 320px; max-height: 620px; object-fit: cover; }
.hero-dots { position: absolute; bottom: 16px; left: 0; right: 0; text-align: center; z-index: 5; }
.hero-dots button { width: 28px; height: 3px; margin: 0 4px; background: rgba(255,255,255,.45); border-radius: 2px; transition: background .3s; }
.hero-dots button.active { background: #fff; }
.hero-cta { position: absolute; inset: 0; z-index: 4; display: flex; align-items: center; background: linear-gradient(180deg, rgba(10,12,16,.15) 0%, rgba(10,12,16,.55) 100%); }
.hero-title { color: #fff; font-size: 30px; letter-spacing: 3px; text-shadow: 0 2px 12px rgba(0,0,0,.4); }
.hero-sub { color: rgba(255,255,255,.85); margin: 10px 0 26px; letter-spacing: 2px; }

/* 首页：解决方案 */
.section-solutions { background: var(--gray-1); }
.sol-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.sol-card { background: #fff; border-radius: var(--radius); padding: 26px 16px; text-align: center; box-shadow: var(--shadow); transition: all .3s; }
.sol-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.sol-icon { width: 64px; height: 64px; margin: 0 auto 14px; }
.sol-icon img { width: 100%; height: 100%; object-fit: contain; }
.sol-title { font-size: 17px; color: var(--dark); margin-bottom: 4px; }
.sol-en { font-size: 12px; color: var(--gray-3); letter-spacing: 1px; }
.sol-more { display: inline-block; margin-top: 14px; font-size: 13px; color: var(--primary); opacity: 0; transform: translateY(4px); transition: all .3s; }
.sol-card:hover .sol-more { opacity: 1; transform: translateY(0); }

/* 首页：关于我们 */
.section-about { background: #171a1f; color: #d6d9de; }
.about-grid { display: grid; gap: 30px; }
.about-media { min-height: 260px; background-size: cover; background-position: center; border-radius: var(--radius); position: relative; overflow: hidden; display: flex; align-items: flex-end; }
.about-media::before { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, transparent 30%, rgba(10,12,16,.72)); }
.about-media-text { position: relative; padding: 24px; }
.about-media-text h2 { color: #fff; font-size: 22px; letter-spacing: 2px; }
.about-media-text p { color: rgba(255,255,255,.72); font-size: 13px; margin-top: 4px; }
.about-body .accent-title { color: #fff; }
.about-text { font-size: 14.5px; color: #b9bec6; text-align: justify; }
.section-about .section-more { text-align: left; }

/* 首页：知名客户 */
.customer-slider { position: relative; }
.slider-track { display: flex; gap: 12px; overflow-x: auto; scroll-snap-type: x mandatory; scrollbar-width: none; padding-bottom: 4px; }
.slider-track::-webkit-scrollbar { display: none; }
.customer-item { flex: 0 0 44%; scroll-snap-align: start; background: #fff; border: 1px solid var(--gray-2); border-radius: var(--radius); padding: 14px; display: flex; align-items: center; justify-content: center; min-height: 84px; }
.customer-item img { max-height: 56px; width: auto; object-fit: contain; }
.slider-btn { display: none; position: absolute; top: 50%; transform: translateY(-50%); width: 36px; height: 36px; border-radius: 50%; background: rgba(255,255,255,.9); box-shadow: var(--shadow); color: var(--dark); font-size: 16px; z-index: 5; }
.slider-btn:hover { background: var(--primary); color: #fff; }
.slider-prev { left: -8px; }
.slider-next { right: -8px; }
.slider-btn::before { content: "‹"; font-size: 24px; line-height: 1; }
.slider-next::before { content: "›"; }

/* 内页横幅 */
.page-banner { background-size: cover; background-position: center; padding: 70px 0; position: relative; background-color: #171a1f; }
.page-banner::before { content: ""; position: absolute; inset: 0; background: linear-gradient(180deg, rgba(10,12,16,.35), rgba(10,12,16,.6)); }
.page-banner .container { position: relative; }
.page-banner-title { color: #fff; font-size: 28px; letter-spacing: 3px; }
.page-banner-en { color: rgba(255,255,255,.6); font-size: 13px; letter-spacing: 4px; margin-top: 6px; text-transform: uppercase; }

/* 内页主体 */
.page-body { display: grid; gap: 26px; padding: 40px 0 64px; }
.page-side { display: flex; flex-direction: column; gap: 16px; }
.side-box { background: var(--gray-1); border-radius: var(--radius); padding: 18px; }
.side-title { font-size: 16px; color: var(--dark); padding-left: 10px; margin-bottom: 10px; border-left: 3px solid var(--primary); }
.side-nav { list-style: none; }
.side-nav a { display: block; padding: 9px 10px; border-radius: 6px; font-size: 14.5px; color: var(--text-light); }
.side-nav li.active a, .side-nav a:hover { background: #fff; color: var(--primary); font-weight: 600; box-shadow: var(--shadow); }
.side-contact .side-tel { color: var(--primary); font-size: 18px; font-weight: 700; margin: 4px 0 8px; }
.side-addr { font-size: 13px; color: var(--text-light); }
.page-main { min-width: 0; }

/* 富文本 */
.rich-content { font-size: 15.5px; color: var(--text); }
.rich-content p { margin: 0 0 14px; text-align: justify; }
.rich-content h3 { font-size: 19px; color: var(--dark); margin: 28px 0 12px; padding-left: 12px; border-left: 4px solid var(--primary); }
.rich-content h4 { font-size: 16.5px; color: var(--dark); margin: 20px 0 8px; }
.rich-content ul, .rich-content ol { margin: 0 0 14px; padding-left: 6px; }
.rich-content li { margin-bottom: 6px; }
.rich-content .rich-img img { border-radius: var(--radius); margin: 18px auto; box-shadow: var(--shadow); }
.rich-content .hotline-callout { background: #fdf0f0; border: 1px solid #f3c9ca; color: var(--primary); border-radius: var(--radius); padding: 12px 16px; font-weight: 600; text-align: center; }
.rich-content .service-list { list-style: none; }
.rich-content .value-grid { list-style: none; display: grid; grid-template-columns: 1fr; gap: 10px; }
.rich-content .value-grid li { background: var(--gray-1); border-radius: var(--radius); padding: 12px 16px; }

/* 企业文化 */
.culture-grid { display: grid; grid-template-columns: 1fr; gap: 16px; margin-top: 22px; }
.culture-item { background: #fff; border: 1px solid var(--gray-2); border-radius: var(--radius); padding: 26px 18px; text-align: center; transition: all .3s; }
.culture-item:hover { border-color: var(--primary); box-shadow: var(--shadow-lg); transform: translateY(-4px); }
.culture-icon { width: 56px; height: 56px; margin: 0 auto 12px; }
.culture-icon img { width: 100%; height: 100%; object-fit: contain; }
.culture-item h3 { font-size: 17px; color: var(--primary); margin-bottom: 6px; }
.culture-item p { font-size: 14px; color: var(--text-light); }

/* 案例 */
.case-grid { display: grid; grid-template-columns: 1fr; gap: 22px; padding: 8px 0 40px; }
.case-card { background: #fff; }
.case-img { display: block; border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); aspect-ratio: 16 / 10; }
.case-img img { width: 100%; height: 100%; object-fit: cover; transition: transform .4s; }
.case-card:hover .case-img img { transform: scale(1.05); }
.case-title { text-align: center; font-size: 15px; color: var(--dark); margin-top: 14px; padding: 0 6px; font-weight: 500; }

/* 荣誉 / 合作伙伴 */
.honor-grid { display: grid; grid-template-columns: 1fr; gap: 22px; padding-bottom: 30px; }
.honor-card { text-align: center; }
.honor-img { display: block; border-radius: var(--radius); overflow: hidden; border: 1px solid var(--gray-2); background: #fff; transition: all .3s; }
.honor-img:hover { box-shadow: var(--shadow-lg); transform: translateY(-4px); }
.honor-card img { width: 100%; aspect-ratio: 728 / 460; object-fit: contain; padding: 10px; }
.honor-card figcaption { margin-top: 12px; font-size: 15px; color: var(--dark); font-weight: 500; }
.partner-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; padding-bottom: 30px; }
.partner-item { background: #fff; border: 1px solid var(--gray-2); border-radius: var(--radius); padding: 18px 12px; display: flex; align-items: center; justify-content: center; min-height: 90px; transition: all .3s; }
.partner-item:hover { box-shadow: var(--shadow); }
.partner-item img { max-height: 60px; width: auto; object-fit: contain; }

/* FAQ */
.faq-list { display: flex; flex-direction: column; gap: 12px; }
.faq-item { background: #fff; border: 1px solid var(--gray-2); border-radius: var(--radius); overflow: hidden; transition: border-color .25s; }
.faq-item[open] { border-color: var(--primary); }
.faq-item summary { cursor: pointer; padding: 15px 18px; font-size: 15.5px; font-weight: 600; color: var(--dark); list-style: none; position: relative; padding-right: 44px; }
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after { content: "+"; position: absolute; right: 18px; top: 50%; transform: translateY(-50%); width: 22px; height: 22px; border-radius: 50%; background: var(--gray-1); display: flex; align-items: center; justify-content: center; color: var(--primary); font-size: 16px; line-height: 1; }
.faq-item[open] summary::after { content: "−"; }
.faq-answer { padding: 2px 18px 16px; font-size: 14.5px; color: var(--text-light); }

/* 联系我们 */
.contact-main { width: 100%; }
.contact-grid { display: grid; gap: 26px; }
.contact-media img { border-radius: var(--radius); box-shadow: var(--shadow); width: 100%; }
.contact-detail { list-style: none; margin: 6px 0 26px; }
.contact-detail li { padding: 13px 4px; border-bottom: 1px dashed var(--gray-2); display: flex; flex-wrap: wrap; font-size: 15.5px; }
.ci-label { color: var(--gray-3); flex: 0 0 auto; margin-right: 4px; }
.contact-detail a { color: var(--primary); font-weight: 600; }

/* 404 */
.error-page { text-align: center; padding: 70px 0 90px; }
.error-code { font-size: 88px; font-weight: 800; color: var(--primary); line-height: 1; }
.error-msg { color: var(--text-light); margin: 18px 0 30px; }
.error-actions { display: flex; gap: 14px; justify-content: center; flex-wrap: wrap; }

/* 灯箱 */
.lightbox { position: fixed; inset: 0; z-index: 300; background: rgba(10,12,16,.88); display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 30px; }
.lightbox[hidden] { display: none; }
.lightbox-img { max-width: 92%; max-height: 78vh; border-radius: 6px; box-shadow: var(--shadow-lg); }
.lightbox-caption { color: rgba(255,255,255,.85); margin-top: 16px; font-size: 15px; }
.lightbox-close { position: absolute; top: 18px; right: 22px; color: #fff; font-size: 34px; width: 44px; height: 44px; line-height: 1; }

/* 页脚 */
.site-footer { background: #171a1f; color: #b9bec6; }
.footer-grid { display: grid; grid-template-columns: 1fr; gap: 28px; padding: 44px 0 30px; }
.footer-logo { height: 34px; width: auto; margin-bottom: 14px; }
.footer-desc { font-size: 13.5px; color: #8b9099; max-width: 300px; }
.footer-col h3 { color: #fff; font-size: 15.5px; margin-bottom: 14px; letter-spacing: 1px; position: relative; padding-bottom: 10px; }
.footer-col h3::after { content: ""; position: absolute; left: 0; bottom: 0; width: 26px; height: 2px; background: var(--primary); }
.footer-col ul { list-style: none; }
.footer-col ul li { margin-bottom: 9px; }
.footer-col a { font-size: 13.5px; color: #8b9099; }
.footer-col a:hover { color: #fff; }
.footer-contact .contact-list { list-style: none; }
.footer-contact li { font-size: 13.5px; color: #8b9099; margin-bottom: 9px; }
.footer-contact .ci-label { display: inline; }
.footer-bar { border-top: 1px solid rgba(255,255,255,.08); padding: 16px 0; }
.footer-bar-inner { display: flex; flex-direction: column; gap: 6px; text-align: center; }
.footer-bar p { font-size: 12.5px; color: #6f747c; }
.footer-bar a { color: #6f747c; }
.footer-bar a:hover { color: #fff; }

/* 返回顶部 */
.back-top {
    position: fixed; right: 18px; bottom: 24px; z-index: 90;
    width: 42px; height: 42px; border-radius: 50%;
    background: var(--primary); color: #fff; font-size: 18px;
    box-shadow: var(--shadow-lg); opacity: 0; visibility: hidden;
    transition: all .3s;
}
.back-top.show { opacity: 1; visibility: visible; }
.back-top:hover { background: var(--primary-dark); }

/* 动效 */
.reveal { opacity: 0; transform: translateY(22px); transition: opacity .6s ease, transform .6s ease; }
.reveal.visible { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
    .reveal { opacity: 1; transform: none; transition: none; }
    html { scroll-behavior: auto; }
}

/* ============ 平板 ≥768px ============ */
@media (min-width: 768px) {
    .section { padding: 72px 0; }
    .hero-title { font-size: 38px; }
    .sol-grid { grid-template-columns: repeat(4, 1fr); gap: 18px; }
    .customer-item { flex: 0 0 23%; }
    .case-grid { grid-template-columns: repeat(2, 1fr); gap: 26px; }
    .honor-grid { grid-template-columns: repeat(2, 1fr); gap: 26px; }
    .partner-grid { grid-template-columns: repeat(3, 1fr); }
    .culture-grid { grid-template-columns: repeat(2, 1fr); }
    .rich-content .value-grid { grid-template-columns: repeat(2, 1fr); }
    .footer-grid { grid-template-columns: repeat(2, 1fr); gap: 36px; }
    .footer-bar-inner { flex-direction: row; justify-content: space-between; }
    .slider-btn { display: block; }
    .error-code { font-size: 110px; }
    .page-banner { padding: 90px 0; }
    .page-banner-title { font-size: 32px; }
}

/* ============ 桌面 ≥1024px ============ */
@media (min-width: 1024px) {
    .section { padding: 84px 0; }
    .nav-toggle { display: none; }
    .main-nav { display: block; }
    .header-tel { display: block; }
    .hero-title { font-size: 44px; }
    .hero-sub { font-size: 17px; }
    .about-grid { grid-template-columns: 1fr 1fr; align-items: center; }
    .page-body { grid-template-columns: 250px 1fr; gap: 36px; }
    .case-grid { grid-template-columns: repeat(3, 1fr); }
    .honor-grid { grid-template-columns: repeat(4, 1fr); }
    .partner-grid { grid-template-columns: repeat(5, 1fr); }
    .culture-grid { grid-template-columns: repeat(4, 1fr); }
    .contact-grid { grid-template-columns: 1fr 1fr; align-items: center; }
    .footer-grid { grid-template-columns: 1.4fr 1fr 1fr 1.2fr 1.4fr; gap: 30px; }
    .customer-item { flex: 0 0 15.5%; }
    .sol-grid-page { grid-template-columns: repeat(4, 1fr); }
    .section-title { font-size: 30px; }
    .page-banner { padding: 110px 0; }
    .page-banner-title { font-size: 36px; }
    .rich-content { font-size: 16px; }
}

/* 无侧栏页面（案例/联系）保持单列全宽 */
.page-body.no-side { grid-template-columns: 1fr; }