/* ==========================================================================
   江苏大津重工有限公司官网 — 样式表
   设计基准：红帽官网排版骨架 × 海洋钢青色系（1440px 桌面设计稿 1:1 还原）
   ========================================================================== */

/* ---------- 设计变量（与画布设计稿逐像素对应） ---------- */
:root {
  /* 色彩 */
  --ink: #151515;            /* 主黑（导航/深色板块底） */
  --ink-2: #292929;          /* 深色卡片底 */
  --ink-3: #383838;          /* 深色描边 */
  --sea: #0B2E3F;            /* 深海钢青（Hero/页脚底） */
  --sea-2: #143D52;          /* 青色胶囊/次级按钮底 */
  --sea-3: #2E6B85;          /* 青色描边 */
  --sea-line: #1F4557;       /* 页脚分隔线 */
  --sea-text: #9CC4D6;       /* 深底上的青色文字 */
  --accent: #EE3D0A;         /* 强调橙红 */
  --gray-bg: #F2F2F2;        /* 浅灰板块底 */
  --gray-line: #E0E0E0;      /* 浅灰描边 */
  --gray-mid: #C7C7C7;       /* 深底正文/浅灰描边 */
  --gray-text: #4D4D4D;      /* 浅底正文 */
  --gray-mute: #8C8C8C;      /* 弱化文字 */
  --white: #FFFFFF;

  /* 字体 */
  --font-display: "Red Hat Display", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;
  --font-body: "Red Hat Text", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Source Han Sans SC", sans-serif;

  /* 布局 */
  --container: 1440px;
  --pad-x: 64px;
  --radius: 4px;
  --radius-pill: 999px;
  --nav-h: 80px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ---------- 基础重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--white);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; }
a { color: inherit; text-decoration: none; }
ul, ol, dl, dd, figure, p, h1, h2, h3 { margin: 0; padding: 0; }
ul, ol { list-style: none; }
button { font: inherit; border: 0; background: none; cursor: pointer; }

.container {
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: var(--pad-x);
}
section { scroll-margin-top: var(--nav-h); }

/* ---------- 通用组件 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border-radius: var(--radius-pill);
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 15px;
  line-height: 1;
  padding: 13px 26px;
  white-space: nowrap;
  transition: transform 0.2s var(--ease), background-color 0.2s var(--ease),
              border-color 0.2s var(--ease), box-shadow 0.2s var(--ease);
}
.btn-lg { font-size: 16px; padding: 15px 30px; }
.btn-primary { background: var(--accent); color: var(--white); }
.btn-primary:hover { background: #D53405; transform: translateY(-1px); }
.btn-ghost-sea { background: var(--sea-2); color: var(--sea-text); border: 1px solid var(--sea-3); }
.btn-ghost-sea:hover { border-color: var(--sea-text); transform: translateY(-1px); }

.eyebrow {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 13px;
  color: var(--accent);
  letter-spacing: 0.02em;
}

/* ---------- 占位图（替换真实图片时直接换成 <img>） ---------- */
.ph {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  margin: 0;
  background:
    linear-gradient(rgba(21, 21, 21, 0.04) 1px, transparent 1px) 0 0 / 100% 32px,
    linear-gradient(90deg, rgba(21, 21, 21, 0.04) 1px, transparent 1px) 0 0 / 32px 100%,
    #E6E8EA;
  border-radius: var(--radius);
  overflow: hidden;
}
.ph-ic { width: 34px; height: 34px; color: #9AA1A8; }
.ph figcaption,
.ph > figcaption {
  font-family: var(--font-body);
  font-size: 14px;
  color: #7A8087;
  letter-spacing: 0.04em;
}

/* ---------- 真实图片媒体块（.media；多图位加 .gallery 由脚本交叉淡切） ---------- */
.media {
  position: relative;
  display: block;
  margin: 0;
  background: #E6E8EA;
  border-radius: var(--radius);
  overflow: hidden;
}
.media img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  opacity: 0;
  transition: opacity 0.9s var(--ease);
}
.media img.on { opacity: 1; }
/* ---------- 铺满模式（.media-contain 全站统一）：图片铺满卡片内区域，外边缘与卡片边框完全贴合无缝（cover 由 .media img 基础规则提供，无补边无黑边） ---------- */
.media-contain { background: #E6E8EA; }
@media (prefers-reduced-motion: reduce) {
  .media img { transition: none; }
}



/* ---------- 页头导航 ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--ink);
  transition: box-shadow 0.25s var(--ease);
}
.navbar.scrolled { box-shadow: 0 4px 24px rgba(0, 0, 0, 0.35); }
.navbar-inner {
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-text { display: flex; flex-direction: column; gap: 1px; }
.brand-name {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 18px;
  color: var(--white);
  line-height: 1.25;
}
.brand-sub {
  font-family: var(--font-body);
  font-size: 9px;
  letter-spacing: 0.18em;
  color: var(--gray-mute);
}
.nav-menu { display: flex; align-items: center; gap: 36px; }
.nav-link {
  font-family: var(--font-body);
  font-size: 15px;
  color: var(--gray-line);
  transition: color 0.2s var(--ease);
  position: relative;
}
.nav-link:hover { color: var(--white); }
.nav-link.active { color: var(--white); }
.nav-link.active::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: -8px;
  height: 2px;
  background: var(--accent);
  border-radius: 2px;
}
.nav-link-soon { opacity: 0.55; cursor: not-allowed; }
.nav-right { display: flex; align-items: center; gap: 24px; }
.icon-btn { display: inline-flex; padding: 4px; border-radius: 50%; transition: background 0.2s var(--ease); }
.icon-btn:hover { background: rgba(224, 224, 224, 0.12); }
.nav-toggle { display: none; flex-direction: column; gap: 5px; padding: 8px; }
.nav-toggle span {
  width: 22px; height: 2px;
  background: var(--white);
  border-radius: 2px;
  transition: transform 0.25s var(--ease), opacity 0.25s var(--ease);
}
.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); }

/* ---------- Hero ---------- */
.hero { background: var(--sea); }
.hero-grid {
  display: flex;
  align-items: center;
  gap: 64px;
  padding-block: 96px;
}
.hero-left { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 28px; }
.hero-badge {
  align-self: flex-start;
  display: inline-flex;
  padding: 5px 14px;
  border-radius: var(--radius);
  background: var(--sea-2);
  border: 1px solid var(--sea-3);
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 12px;
  color: var(--sea-text);
}
.hero-title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 66px;
  line-height: 78px;
  color: var(--white);
  letter-spacing: 0.01em;
}
.hero-sub {
  font-size: 17px;
  line-height: 30px;
  color: var(--gray-mid);
  max-width: 640px;
}
.hero-cta-row { display: flex; flex-wrap: wrap; align-items: center; gap: 20px; }
.hero-stats { display: flex; flex-wrap: wrap; gap: 48px; padding-top: 28px; }
.stat { display: flex; flex-direction: column; gap: 6px; }
.stat dt {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 34px;
  line-height: 1.15;
  color: var(--white);
}
.stat dd { font-size: 13px; color: var(--gray-mute); }

.hero-visual {
  flex: 0 0 560px;
  width: 560px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}
.hero-ph-main { height: 372px; }
.hero-ph-row { display: flex; gap: 14px; flex: 1 1 auto; min-height: 142px; }
.hero-ph-sub { flex: 1 1 0; height: auto; }

/* ---------- 信任条 ---------- */
.trust-bar { background: var(--gray-bg); }
.trust-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  padding-block: 40px;
}
.trust-label { display: flex; flex-direction: column; gap: 8px; }
.trust-main {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 15px;
  color: var(--ink);
}
.trust-sub {
  font-family: var(--font-body);
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--gray-text);
}
.cert-row { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; }
.cert-chip {
  display: inline-flex;
  padding: 9px 18px;
  border-radius: var(--radius);
  border: 1px solid var(--gray-mid);
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 13px;
  color: var(--gray-text);
  background: transparent;
}

/* ---------- 通用 Section ---------- */
.section { padding-block: 96px; }
.section-light { background: var(--white); }
.section-dark { background: var(--ink); }

.section-head {
  display: flex;
  align-items: flex-end;
  gap: 64px;
  margin-bottom: 56px;
}
.section-head-left { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 16px; }
.section-title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 44px;
  line-height: 56px;
  letter-spacing: 0.01em;
}
.section-light .section-title { color: var(--ink); }
.section-dark .section-title { color: var(--white); }
.section-desc {
  flex: 0 0 auto;
  width: 420px;
  font-size: 16px;
  line-height: 26px;
  color: var(--gray-text);
}
.section-dark .section-desc { color: var(--gray-mid); line-height: 28px; }

/* ---------- 核心业务 ---------- */
.biz-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  margin-bottom: 24px;
}
.biz-card {
  display: flex;
  flex-direction: column;
  background: var(--gray-bg);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}
.biz-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(21, 21, 21, 0.10); }
.biz-ph { height: 210px; border-radius: 0; }
.biz-body { display: flex; flex-direction: column; gap: 12px; padding: 28px; }
.card-no {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 12px;
  color: var(--accent);
}
.biz-title {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 22px;
  line-height: 1.35;
  color: var(--ink);
}
.biz-desc { font-size: 14px; line-height: 24px; color: var(--gray-text); }
.biz-wide { width: 100%; height: 380px; }
.biz-caption {
  margin-top: 16px;
  font-size: 14px;
  line-height: 24px;
  color: var(--gray-text);
}

/* ---------- 企业实力与建造基地 ---------- */
.base-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.base-card {
  display: flex;
  flex-direction: column;
  gap: 20px;
  padding: 28px;
  background: var(--ink-2);
  border: 1px solid var(--ink-3);
  border-radius: var(--radius);
  transition: border-color 0.25s var(--ease), transform 0.25s var(--ease);
}
.base-card:hover { border-color: var(--sea-3); transform: translateY(-3px); }
.base-name {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 24px;
  color: var(--white);
}
.base-sub { font-size: 12px; color: var(--gray-mute); margin-top: -12px; }
.base-list { display: flex; flex-direction: column; gap: 12px; }
.base-list li { font-size: 13px; line-height: 22px; color: var(--gray-mid); }

.tech-block {
  display: flex;
  gap: 48px;
  padding-top: 40px;
  margin-top: 8px;
}
.tech-left { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 16px; }
.tech-title {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 30px;
  line-height: 40px;
  color: var(--white);
}
.tech-desc { font-size: 15px; line-height: 26px; color: var(--gray-mid); }
.tech-chips {
  flex: 0 0 620px;
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-content: flex-start;
}
.tech-chip {
  display: inline-flex;
  padding: 11px 20px;
  border-radius: var(--radius-pill);
  background: var(--ink-2);
  border: 1px solid #4D4D4D;
  font-size: 14px;
  color: var(--gray-mid);
  white-space: nowrap;
}

/* ---------- 产品业绩 ---------- */
.prod-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.prod-card {
  display: flex;
  flex-direction: column;
  background: var(--gray-bg);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease);
}
.prod-card:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(21, 21, 21, 0.10); }
.prod-ph { height: 220px; border-radius: 0; }
.prod-body { display: flex; flex-direction: column; gap: 10px; padding: 24px; }
.prod-tag {
  font-family: var(--font-body);
  font-weight: 500;
  font-size: 12px;
  color: var(--accent);
}
.prod-name {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 19px;
  line-height: 28px;
  color: var(--ink);
}
.prod-specs { display: flex; flex-direction: column; gap: 4px; }
.prod-specs li { font-size: 13px; line-height: 22px; color: var(--gray-text); }


/* ---------- 页脚 ---------- */
.footer { background: var(--sea); color: var(--white); }
.footer-top {
  display: flex;
  justify-content: space-between;
  gap: 64px;
  padding-block: 72px;
}
.footer-brand { flex: 1 1 auto; min-width: 0; display: flex; flex-direction: column; gap: 20px; max-width: 560px; }
.footer-brand .brand { gap: 12px; }
.footer-brand-name {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 19px;
  color: var(--white);
}
.footer-tagline {
  font-family: var(--font-display);
  font-weight: 300;
  font-size: 20px;
  line-height: 30px;
  color: var(--sea-text);
}
.footer-address { font-size: 14px; line-height: 24px; color: var(--gray-mute); }
.footer-cols { display: flex; gap: 72px; }
.footer-col { display: flex; flex-direction: column; gap: 16px; }
.footer-col-title {
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 13px;
  color: var(--white);
  margin-bottom: 2px;
}
.footer-col a {
  font-size: 14px;
  line-height: 26px;
  color: var(--gray-mute);
  transition: color 0.2s var(--ease);
}
.footer-col a:hover { color: var(--sea-text); }
.footer-wordmark {
  padding-bottom: 24px;
  font-family: var(--font-display);
  font-weight: 500;
  font-size: 13px;
  letter-spacing: 0.3em;
  color: var(--sea-3);
}
.footer-bottom { border-top: 1px solid var(--sea-line); }
.footer-bottom-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding-block: 22px;
  font-size: 13px;
  color: var(--gray-mute);
  flex-wrap: wrap;
}
.footer-legal { display: flex; gap: 28px; }
.footer-legal a { color: var(--gray-mute); transition: color 0.2s var(--ease); }
.footer-legal a:hover { color: var(--sea-text); }
.icp-link {
  font-size: 13px;
  color: var(--gray-mute);
  transition: color 0.2s var(--ease);
}
.icp-link:hover { color: var(--sea-text); }

/* ---------- 返回顶部 ---------- */
.back-top {
  position: fixed;
  right: 28px;
  bottom: 28px;
  z-index: 90;
  width: 46px;
  height: 46px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: var(--accent);
  color: var(--white);
  box-shadow: 0 8px 24px rgba(238, 61, 10, 0.35);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0.25s;
}
.back-top.show { opacity: 1; visibility: visible; transform: none; }
.back-top:hover { transform: translateY(-3px); }

/* ---------- 进场动画 ---------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal[data-delay="1"] { transition-delay: 0.1s; }
.reveal[data-delay="2"] { transition-delay: 0.2s; }
.reveal[data-delay="3"] { transition-delay: 0.3s; }
.reveal[data-delay="4"] { transition-delay: 0.4s; }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
}

/* ==========================================================================
   响应式
   ========================================================================== */
@media (max-width: 1360px) {
  .hero-title { font-size: 56px; line-height: 68px; }
  .hero-visual { flex-basis: 480px; width: 480px; }
}

@media (max-width: 1180px) {
  :root { --pad-x: 40px; }
  .hero-grid { gap: 40px; }
  .hero-title { font-size: 48px; line-height: 60px; }
  .hero-visual { flex: 1 1 auto; width: auto; }
  .section-title { font-size: 36px; line-height: 48px; }
  .section-head { flex-direction: column; align-items: flex-start; gap: 20px; }
  .section-desc { width: auto; max-width: 640px; }
  .biz-grid { grid-template-columns: repeat(2, 1fr); }
  .base-grid { grid-template-columns: repeat(2, 1fr); }
  .prod-grid { grid-template-columns: repeat(2, 1fr); }
  .tech-block { flex-direction: column; }
  .tech-chips { flex-basis: auto; }
}

@media (max-width: 920px) {
  .nav-menu {
    position: fixed;
    top: var(--nav-h);
    right: 0;
    z-index: 99;
    flex-direction: column;
    align-items: flex-start;
    gap: 4px;
    width: min(320px, 86vw);
    height: calc(100vh - var(--nav-h));
    padding: 24px;
    background: var(--ink);
    box-shadow: -12px 0 40px rgba(0, 0, 0, 0.4);
    transform: translateX(100%);
    transition: transform 0.3s var(--ease);
    overflow-y: auto;
  }
  .nav-menu.open { transform: none; }
  .nav-link { width: 100%; padding: 14px 8px; font-size: 16px; border-bottom: 1px solid var(--ink-3); }
  .nav-link.active::after { display: none; }
  .nav-toggle { display: flex; }
  .icon-btn { display: none; }

  .hero-grid { flex-direction: column; align-items: stretch; padding-block: 64px; }
  .hero-visual { width: 100%; flex-basis: auto; }
  .hero-ph-main { height: 300px; }
  .trust-inner { flex-direction: column; align-items: flex-start; gap: 20px; }
}

@media (max-width: 680px) {
  :root { --pad-x: 20px; --nav-h: 68px; }
  .section { padding-block: 64px; }
  .hero-title { font-size: 36px; line-height: 48px; }
  .hero-sub { font-size: 15px; line-height: 26px; }
  .hero-stats { gap: 24px 32px; }
  .stat dt { font-size: 26px; }
  .section-title { font-size: 28px; line-height: 38px; }
  .section-head { margin-bottom: 36px; }
  .biz-grid { grid-template-columns: 1fr; }
  .base-grid { grid-template-columns: 1fr; }
  .prod-grid { grid-template-columns: 1fr; }
  .biz-wide { height: 220px; }
  .footer-top { flex-direction: column; gap: 40px; padding-block: 56px; }
  .footer-cols { flex-wrap: wrap; gap: 32px 48px; }
  .footer-bottom-inner { flex-direction: column; gap: 10px; }
  .cert-row { gap: 6px; }
  .cert-chip { padding: 7px 12px; font-size: 12px; }
  .back-top { right: 16px; bottom: 16px; }
}