/* ============================================================
   时来桥梁工程 · 官网
   风格：混凝土灰极简（Concrete Minimal）
   ============================================================ */

:root {
  --ink: #1b1d1f;            /* 近黑 */
  --concrete: #8a8e92;       /* 水泥灰 */
  --concrete-mid: #c9cdd0;   /* 中灰 */
  --concrete-light: #eef0f2; /* 浅灰底 */
  --paper: #ffffff;
  --accent: #ff6b1a;         /* 安全橙点缀 */
  --line: #d9dcdf;
  --mono: "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: -apple-system, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  color: var(--ink);
  background: var(--paper);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

.mono { font-family: var(--mono); font-weight: 400; letter-spacing: .02em; }

.container { max-width: 1180px; margin: 0 auto; padding: 0 28px; }

a { color: inherit; text-decoration: none; }

img { display: block; width: 100%; }

/* ---------- 顶部导航 ---------- */
.site-header {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex; align-items: center; justify-content: space-between;
  height: 68px;
}
.logo { display: flex; align-items: center; gap: 12px; }
.logo-img { width: 42px; height: 42px; object-fit: contain; }
.logo-text { display: flex; flex-direction: column; line-height: 1.2; }
.logo-mark {
  font-size: 17px; font-weight: 800; letter-spacing: .05em;
  white-space: nowrap;
}
.logo-sub {
  font-family: var(--mono); font-size: 8.5px; color: var(--concrete);
  letter-spacing: .12em; white-space: nowrap;
}
.main-nav { display: flex; gap: 34px; }
.main-nav a {
  font-size: 14.5px; font-weight: 500; color: #3a3e42;
  position: relative; padding: 6px 0;
  transition: color .2s;
}
.main-nav a::after {
  content: ""; position: absolute; left: 0; bottom: 0;
  width: 0; height: 2px; background: var(--accent);
  transition: width .25s;
}
.main-nav a:hover { color: var(--ink); }
.main-nav a:hover::after { width: 100%; }
.header-tel { display: flex; flex-direction: column; align-items: flex-end; line-height: 1.2; }
.tel-icon {
  font-family: var(--mono); font-size: 9px; color: var(--concrete);
  letter-spacing: .3em;
}
.tel-num { font-weight: 700; font-size: 16px; letter-spacing: .03em; }
.header-tel:hover .tel-num { color: var(--accent); }

/* 移动端菜单按钮 */
.nav-toggle { display: none; flex-direction: column; gap: 5px;
  background: none; border: none; cursor: pointer; padding: 8px; }
.nav-toggle span { width: 24px; height: 2px; background: var(--ink); display: block; }

/* ---------- HERO ---------- */
.hero {
  position: relative; min-height: 100vh;
  display: flex; flex-direction: column; justify-content: flex-end;
  color: #fff;
}
.hero-bg {
  position: absolute; inset: 0;
  background: url("../img/hero.png") center 35% / cover no-repeat;
}
.hero-shade {
  position: absolute; inset: 0;
  background: linear-gradient(180deg,
    rgba(20,22,24,.30) 0%,
    rgba(20,22,24,.45) 45%,
    rgba(20,22,24,.82) 100%);
}
.hero-content {
  position: relative; z-index: 2;
  padding-top: 140px; padding-bottom: 48px;
}
.hero-kicker {
  font-size: 13px; color: var(--accent);
  letter-spacing: .1em; margin-bottom: 18px;
}
.hero-title {
  font-size: clamp(44px, 7vw, 84px);
  font-weight: 900; line-height: 1.12; letter-spacing: .01em;
  margin-bottom: 22px;
}
.hero-title em { font-style: normal; color: var(--concrete-mid); }
.hero-desc {
  font-size: 17px; color: rgba(255,255,255,.85);
  max-width: 560px; margin-bottom: 36px;
}
.hero-actions { display: flex; gap: 16px; flex-wrap: wrap; }

.btn {
  display: inline-block; padding: 14px 34px;
  font-size: 15px; font-weight: 600; letter-spacing: .06em;
  border: 1px solid transparent; transition: all .22s;
}
.btn-solid { background: var(--accent); color: #fff; }
.btn-solid:hover { background: #e55a0d; transform: translateY(-2px); }
.btn-ghost { border-color: rgba(255,255,255,.6); color: #fff; }
.btn-ghost:hover { border-color: #fff; background: rgba(255,255,255,.1); }

/* 数据条 */
.hero-stats {
  position: relative; z-index: 2;
  border-top: 1px solid rgba(255,255,255,.22);
  background: rgba(15,17,19,.55);
  backdrop-filter: blur(6px);
}
.stats-row {
  display: grid; grid-template-columns: repeat(4, 1fr);
  padding-top: 22px; padding-bottom: 22px;
}
.stat { text-align: center; border-left: 1px solid rgba(255,255,255,.14); }
.stat:first-child { border-left: none; }
.stat b {
  font-size: 34px; font-weight: 800; display: inline-block;
}
.stat b i {
  font-style: normal; font-size: 15px; font-weight: 600;
  color: var(--accent); margin-left: 2px;
}
.stat span {
  display: block; font-size: 12.5px;
  color: rgba(255,255,255,.62); letter-spacing: .12em; margin-top: 2px;
}

/* ---------- 通用 Section ---------- */
.section { padding: 96px 0; }
.section-grey { background: var(--concrete-light); }

.section-head {
  display: flex; align-items: flex-start; gap: 20px;
  margin-bottom: 52px;
}
.sec-no {
  font-size: 13px; color: var(--accent);
  border: 1px solid currentColor;
  padding: 4px 9px; border-radius: 2px; margin-top: 8px;
  white-space: nowrap;
}
.sec-title { font-size: clamp(28px, 3.6vw, 40px); font-weight: 800; letter-spacing: .02em; }
.sec-sub { font-size: 14.5px; color: var(--concrete); margin-top: 6px; }

/* ---------- 业务体系 ---------- */
.services-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px;
}
.service-card {
  position: relative;
  background: var(--paper);
  border: 1px solid var(--line);
  padding: 30px 28px 26px;
  transition: transform .25s, box-shadow .25s, border-color .25s;
}
.service-card:nth-child(4), .service-card:nth-child(5) { grid-column: span 1; }
.service-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 40px rgba(27,29,31,.10);
  border-color: var(--concrete-mid);
}
.card-no { font-size: 11px; color: var(--concrete); letter-spacing: .12em; }
.service-card h3 { font-size: 20px; font-weight: 700; margin: 12px 0 10px; }
.service-card p { font-size: 14px; color: #5a5f64; margin-bottom: 18px; }
.card-tags { display: flex; flex-wrap: wrap; gap: 8px; }
.card-tags i {
  font-style: normal; font-size: 12px; color: #4a4f54;
  background: var(--concrete-light);
  padding: 4px 10px; border-radius: 2px;
}
.card-arrow {
  position: absolute; right: 24px; top: 26px;
  font-size: 18px; color: var(--concrete-mid);
  transition: color .2s, transform .2s;
}
.service-card:hover .card-arrow { color: var(--accent); transform: translateX(4px); }

/* ---------- 产品目录（列表 + 侧边预览 + 弹层） ---------- */
.catalog-layout {
  display: grid; grid-template-columns: 1.15fr .85fr; gap: 48px;
  align-items: start;
}
.product-list { list-style: none; border-top: 1px solid #dfe2e5; }
.product-list li {
  display: flex; align-items: baseline; gap: 18px;
  padding: 15px 14px;
  border-bottom: 1px solid #dfe2e5;
  cursor: pointer;
  transition: padding .25s ease, background .25s, transform .25s;
  position: relative;
}
/* 分组标题行 */
.product-list li.list-group-head {
  cursor: default;
  padding: 30px 14px 10px;
  background: transparent;
  border-bottom: 2px solid var(--ink);
  display: flex; align-items: center; gap: 12px;
  font-size: 15px; font-weight: 800; letter-spacing: .08em;
  color: var(--ink);
}
.product-list li.list-group-head .mono {
  font-size: 11px; font-weight: 400; color: var(--accent);
  border: 1px solid currentColor; padding: 3px 8px;
}
.product-list li.list-group-head:first-child { padding-top: 6px; }
.p-no {
  font-size: 11px; color: var(--concrete);
  letter-spacing: .1em; min-width: 38px;
  transition: color .2s;
}
.p-name {
  font-size: 17px; font-weight: 600;
  white-space: nowrap;
  transition: font-size .25s ease, color .2s;
}
.p-tag {
  font-size: 12.5px; color: var(--concrete);
  margin-left: auto; white-space: nowrap;
  transition: opacity .2s;
  opacity: .75;
}
.p-go {
  font-size: 15px; color: transparent;
  transition: color .2s, transform .2s;
}
/* 悬停：行放大 + 橙色编号 + 右箭头浮现 */
.product-list li:hover {
  background: var(--paper);
  padding-left: 24px;
  transform: translateX(4px);
}
.product-list li:hover .p-no { color: var(--accent); }
.product-list li:hover .p-name { font-size: 19.5px; color: var(--ink); }
.product-list li:hover .p-tag { opacity: 1; color: #6a7076; }
.product-list li:hover .p-go { color: var(--accent); transform: translateX(2px); }
.product-list li.active {
  background: var(--paper);
  padding-left: 24px;
}
.product-list li.active .p-no { color: var(--accent); }

/* 侧边预览（sticky 跟随） */
.product-preview { position: sticky; top: 96px; }
.preview-frame {
  position: relative; overflow: hidden;
  border: 1px solid #d5d9dc;
  background: #e4e7ea;
}
.preview-frame img {
  aspect-ratio: 4/3; object-fit: cover; width: 100%;
  display: block;
  animation: fadeImg .45s ease;
}
@keyframes fadeImg {
  from { opacity: .25; transform: scale(1.015); }
  to   { opacity: 1;  transform: scale(1); }
}
.preview-cap {
  position: absolute; left: 0; bottom: 0;
  background: rgba(23,25,28,.78);
  color: #fff; font-size: 11px; letter-spacing: .1em;
  padding: 7px 14px;
}
.preview-hint {
  display: block; margin-top: 12px;
  font-size: 11.5px; color: var(--concrete);
  letter-spacing: .04em;
}

/* ---------- 产品详情弹层 ---------- */
.modal { display: none; }
.modal.open { display: block; }
.modal-mask {
  position: fixed; inset: 0; z-index: 200;
  background: rgba(18,20,22,.62);
  backdrop-filter: blur(3px);
}
.modal-body {
  position: fixed; z-index: 201;
  top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: min(960px, calc(100vw - 36px));
  max-height: calc(100vh - 60px);
  overflow: auto;
  background: var(--paper);
  border: 1px solid var(--line);
  box-shadow: 0 30px 80px rgba(0,0,0,.35);
  animation: modalIn .3s ease;
}
@keyframes modalIn {
  from { opacity: 0; transform: translate(-50%, -47%); }
  to   { opacity: 1; transform: translate(-50%, -50%); }
}
.modal-close {
  position: absolute; top: 10px; right: 14px; z-index: 5;
  width: 40px; height: 40px;
  background: none; border: none;
  font-size: 30px; color: #fff;
  cursor: pointer; line-height: 1;
  text-shadow: 0 1px 6px rgba(0,0,0,.5);
  transition: color .2s;
}
.modal-close:hover { color: var(--accent); }
.modal-grid { display: grid; grid-template-columns: 1fr 1fr; }
.modal-visual {
  position: relative; background: #e4e7ea;
  display: flex; flex-direction: column; justify-content: center;
}
.modal-visual img#modalImg {
  width: 100%; height: 100%; min-height: 340px; object-fit: cover;
  transition: opacity .13s ease;
}
.modal-thumbs {
  display: flex; gap: 8px;
  padding: 10px; background: rgba(23,25,28,.72);
}
.modal-thumbs .thumb {
  width: 62px; height: 62px; padding: 0;
  border: 2px solid transparent; cursor: pointer;
  background: none; overflow: hidden;
  transition: border-color .2s, transform .2s;
}
.modal-thumbs .thumb img { width: 100%; height: 100%; object-fit: cover; display: block; }
.modal-thumbs .thumb:hover { transform: translateY(-2px); }
.modal-thumbs .thumb.cur { border-color: var(--accent); }
.modal-info { padding: 42px 38px 36px; }
.modal-no { font-size: 11.5px; color: var(--accent); letter-spacing: .14em; }
.modal-info h3 { font-size: 26px; font-weight: 800; margin: 10px 0 4px; }
.modal-tagline {
  font-size: 14.5px; color: var(--concrete); margin-bottom: 16px;
}
.modal-desc { font-size: 14.5px; color: #3a3e42; margin-bottom: 18px; }
.modal-specs {
  list-style: none; margin-bottom: 26px;
  border-top: 1px solid var(--line);
}
.modal-specs li {
  font-size: 12.5px; color: #4a4f54;
  padding: 8px 0; border-bottom: 1px dashed var(--line);
  display: flex; gap: 14px;
}
.modal-specs li b {
  color: var(--concrete); font-weight: 400; min-width: 70px;
}
.modal-wechat {
  margin-top: 12px; font-size: 11.5px; color: var(--concrete);
}

/* ---------- 项目案例 ---------- */
.cases-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px;
}
.case-card {
  position: relative; overflow: hidden;
  border: 1px solid var(--line); background: var(--paper);
  cursor: pointer;
  transition: border-color .25s, transform .25s, box-shadow .25s;
}
.case-card:hover {
  border-color: var(--accent);
  transform: translateY(-5px);
  box-shadow: 0 14px 34px rgba(20,24,28,.10);
}
.case-card img { aspect-ratio: 4/3; object-fit: cover; transition: transform .5s; }
.case-card:hover img { transform: scale(1.05); }
.case-card figcaption { padding: 16px 18px 20px; }
.case-card figcaption .mono { font-size: 10.5px; color: var(--accent); letter-spacing: .14em; }
.case-card figcaption b { display: block; font-size: 16.5px; margin: 6px 0 4px; }
.case-card figcaption p { font-size: 13px; color: var(--concrete); }
.case-card::after {
  content: "查看现场图"; position: absolute; right: 12px; top: 12px;
  font-family: var(--mono); font-size: 10px; letter-spacing: .12em;
  color: #fff; background: rgba(20,24,28,.55);
  padding: 4px 9px; border-radius: 2px;
  opacity: 0; transition: opacity .25s;
}
.case-card:hover::after { opacity: 1; }

.case-placeholder {
  display: flex; align-items: center; justify-content: center;
  min-height: 280px;
  background:
    repeating-linear-gradient(45deg, #f4f5f7 0 14px, #eef0f2 14px 28px);
  border: 1px dashed var(--concrete-mid);
}
.case-placeholder figcaption { text-align: center; padding: 20px; }
.case-placeholder b { color: var(--concrete); }

/* ---------- 抖音实拍 ---------- */
.section-dark { background: #23262a; color: #fff; }
.head-on-dark .sec-sub { color: #9aa0a6; }

.douyin-layout {
  display: grid; grid-template-columns: 1fr 300px; gap: 48px;
  align-items: center;
}
.douyin-feed {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px;
}
.dy-card { display: block; transition: transform .25s; background: none; border: none; padding: 0; cursor: pointer; text-align: left; }
.dy-card:hover { transform: translateY(-6px); }
.dy-cover {
  display: block; aspect-ratio: 16/10;
  background: #23262a;
  border: 1px solid #3d4249;
  position: relative; overflow: hidden;
}
.dy-cover img {
  width: 100%; height: 100%; object-fit: cover; display: block;
  filter: saturate(.9);
  transition: filter .25s;
}
.dy-card:hover .dy-cover img { filter: saturate(1.05); }
.dy-play {
  position: absolute; left: 50%; top: 50%;
  width: 54px; height: 54px; margin: -27px 0 0 -27px;
  border-radius: 50%;
  background: rgba(255,255,255,.92);
  color: var(--ink);
  display: flex; align-items: center; justify-content: center;
  font-size: 20px; padding-left: 4px;
  box-shadow: 0 4px 18px rgba(0,0,0,.35);
  transition: transform .2s, background .2s;
}
.dy-card:hover .dy-play { transform: scale(1.12); background: #fff; }
.dy-duration {
  position: absolute; right: 8px; bottom: 8px;
  background: rgba(0,0,0,.65); color: #fff;
  font-family: var(--mono); font-size: 11px;
  padding: 2px 7px; border-radius: 2px;
}
.dy-title {
  display: block; padding: 12px 4px;
  font-size: 13.5px; color: #c9cdd0;
}
.dy-card:hover .dy-title { color: #fff; }

.douyin-cta { text-align: center; }
.qr-slot {
  width: 170px; height: 170px; margin: 0 auto 14px;
  border: 1px solid #4a5058;
  display: flex; flex-direction: column; align-items: center; justify-content: center;
  background: #fff;
  overflow: hidden;
  padding: 8px;
}
.qr-img { width: 100%; height: 100%; object-fit: contain; }
.qr-caption { color: #c9cdd0; font-size: 12px; margin-top: 12px; }
.douyin-cta p { color: #c9cdd0; font-size: 14.5px; margin-bottom: 20px; }
.btn-dy { background: #fff; color: var(--ink); width: 100%; }
.btn-dy:hover { background: var(--accent); color: #fff; }

/* ---------- 视频播放弹层 ---------- */
.video-modal {
  position: fixed; inset: 0; z-index: 220;
  display: none;
  align-items: center; justify-content: center;
}
.video-modal.open { display: flex; }
.video-mask {
  position: absolute; inset: 0;
  background: rgba(10,12,14,.88);
}
.video-body {
  position: relative; z-index: 1;
  width: min(920px, 92vw);
  max-height: 88vh;
  animation: modalIn .25s ease;
}
.video-body video {
  width: 100%; max-height: 82vh; display: block;
  background: #000;
  outline: none;
  border: 1px solid #3d4249;
}
.video-close {
  position: absolute; right: -14px; top: -46px;
  font-size: 30px; color: #fff;
  background: none; border: none; cursor: pointer;
  line-height: 1;
}
.video-close:hover { color: var(--accent); }

/* ---------- 关于我们 ---------- */
.about-grid {
  display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px;
  align-items: center;
}
.about-p { font-size: 16px; color: #3a3e42; margin-bottom: 16px; }
.about-meta {
  list-style: none; margin-top: 28px;
  border-top: 1px solid var(--line); padding-top: 20px;
}
.about-meta li {
  font-size: 13px; color: #5a5f64;
  display: flex; gap: 18px; padding: 7px 0;
}
.about-meta li span {
  color: var(--concrete); min-width: 64px;
  letter-spacing: .08em;
}
.about-visual img {
  border: 1px solid var(--line);
  filter: saturate(.85);
}

/* ---------- 页脚 ---------- */
.site-footer {
  background: #1b1d1f; color: #9aa0a6;
  padding: 56px 0 40px;
}
.footer-inner { display: flex; flex-wrap: wrap; gap: 40px; justify-content: space-between; }
.footer-brand .footer-logo { width: 54px; height: 54px; object-fit: contain; margin-bottom: 14px; }
.footer-brand .footer-co {
  display: block; color: #fff; font-size: 20px; font-weight: 800; letter-spacing: .05em;
}
.footer-slogan { display: block; font-size: 9px; letter-spacing: .26em; margin-top: 8px; color: #5c6268; }
.footer-nav { display: flex; gap: 26px; align-items: center; }
.footer-nav a { font-size: 13.5px; color: #c9cdd0; }
.footer-nav a:hover { color: #fff; }
.footer-info { text-align: right; font-size: 11.5px; line-height: 2; color: #6b7178; }
.footer-info a { color: #8a9096; text-decoration: underline; }
.footer-info a:hover { color: #fff; }

/* ---------- 响应式 ---------- */
@media (max-width: 1060px) {
  .logo-sub { display: none; }
  .logo-mark { font-size: 15px; }
  .main-nav { gap: 22px; }
}

@media (max-width: 960px) {
  .services-grid { grid-template-columns: repeat(2, 1fr); }
  .cases-grid { grid-template-columns: repeat(2, 1fr); }
  .catalog-layout { grid-template-columns: 1fr; gap: 26px; }
  .product-preview { position: static; }
  .modal-grid { grid-template-columns: 1fr; }
  .modal-visual img { min-height: 220px; max-height: 300px; }
  .modal-info { padding: 28px 24px; }
  .douyin-layout { grid-template-columns: 1fr; }
  .douyin-cta { max-width: 300px; margin: 0 auto; }
  .about-grid { grid-template-columns: 1fr; gap: 36px; }
  .footer-info { text-align: left; }
}

@media (max-width: 720px) {
  .section { padding: 68px 0; }
  .main-nav {
    position: fixed; top: 68px; left: 0; right: 0;
    background: #fff; border-bottom: 1px solid var(--line);
    flex-direction: column; gap: 0; padding: 10px 28px 18px;
    display: none;
  }
  .main-nav.open { display: flex; }
  .main-nav a { padding: 12px 0; border-bottom: 1px dashed var(--line); font-size: 16px; }
  .nav-toggle { display: flex; }
  .header-tel { display: none; }
  .services-grid { grid-template-columns: 1fr; }
  .cases-grid { grid-template-columns: 1fr; }
  .douyin-feed { grid-template-columns: repeat(3, 1fr); gap: 10px; }
  .p-name { font-size: 15.5px; }
  .p-tag { display: none; }
  .product-list li { padding: 13px 10px; }
  .product-list li:hover { padding-left: 16px; }
  .product-list li:hover .p-name { font-size: 17px; }
  .stats-row { grid-template-columns: repeat(2, 1fr); row-gap: 14px; }
  .stat:nth-child(3) { border-left: none; }
}