/* 基础样式：白底黑字 */
:root {
  --bg: #ffffff;
  --text: #111111;
  --muted: #555555;
  --border: #e5e5e5;
  --accent: #0a7f44; /* 绿色点缀 */
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.6;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 16px;
}

/* Header */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: transparent;
  transition: background 240ms ease, box-shadow 240ms ease, border-color 240ms ease;
}
.site-header.is-scrolled {
  background: #ffffff;
  border-bottom: 1px solid var(--border);
  box-shadow: 0 6px 20px rgba(0,0,0,0.06);
}
.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.brand { display: inline-block; }
.brand-logo { height: 28px; width: auto; display: block; }
.site-header:not(.is-scrolled) .brand-logo { filter: brightness(0) invert(1); }
.nav { display: flex; gap: 16px; }
.nav-link {
  text-decoration: none;
  padding: 8px 10px;
  border-radius: 6px;
  transition: color 180ms ease, background 180ms ease;
}
.site-header:not(.is-scrolled) .nav-link { color: #ffffff; }
.site-header:not(.is-scrolled) .nav-link:hover { background: rgba(255,255,255,0.12); }
.site-header.is-scrolled .nav-link { color: var(--text); }
.site-header.is-scrolled .nav-link:hover { background: #f7f7f7; }
.lang-switch {
  border: 1px solid var(--border);
  padding: 8px 10px;
  border-radius: 6px;
  cursor: pointer;
  transition: all 180ms ease;
}
.site-header:not(.is-scrolled) .lang-switch {
  background: transparent;
  border-color: rgba(255,255,255,0.6);
  color: #ffffff;
}
.site-header.is-scrolled .lang-switch {
  background: #ffffff;
  color: var(--text);
}

/* 语言选择下拉 */
.lang { position: relative; }
.lang-menu {
  position: absolute; right: 0; top: calc(100% + 8px);
  min-width: 140px;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 10px 24px rgba(0,0,0,0.08);
  padding: 6px;
  display: none;
}
.lang.open .lang-menu { display: block; }
.lang-item {
  display: block;
  padding: 8px 10px;
  border-radius: 6px;
  text-decoration: none;
  color: var(--text);
}
.lang-item:hover { background: #f7f7f7; }
.site-header:not(.is-scrolled) .lang-menu { background: rgba(255,255,255,0.95); }

/* Hero */
.hero {
  position: relative;
  height: 100vh;
  min-height: 540px;
  overflow: hidden;
}
.hero-bg {
  position: absolute; inset: 0;
  background-image: url('images/hero-top.jpg');
  background-size: cover;
  background-position: center;
  filter: brightness(0.8);
}
.hero-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(0,0,0,0.35) 0%, rgba(0,0,0,0.25) 40%, rgba(0,0,0,0.1) 100%);
}
.hero-content {
  position: relative;
  z-index: 1;
  height: 100%;
  display: grid;
  place-items: center;
  text-align: center;
  padding: 0 16px;
}
.hero-inner { width: 100%; }
@media (min-width: 800px) {
  .hero-content { align-items: center; justify-items: start; text-align: left; }
}
.hero-copy { max-width: 800px; }
.hero-title {
  color: #ffffff;
  font-size: clamp(28px, 6vw, 56px);
  margin: 0 0 4px; /* 让标题与副标题更接近 */
}
.hero-sub {
  color: #ffffff;
  font-size: clamp(16px, 2.3vw, 22px);
  margin: 0;
}

/* Sections */
.section { padding: 64px 0; }
.section-title { font-size: 28px; margin: 0 0 8px; }
.section-lead { color: var(--muted); margin-bottom: 24px; }

/* Page hero (用于二级页面顶部横幅) */
.page-hero {
  position: relative;
  margin-top: 0; /* 与首页 hero 一致，背景直达顶部 */
  min-height: 240px;
  display: grid;
  place-items: center;
  background-size: cover;
  background-position: center;
}
.page-hero::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(0,0,0,0.35), rgba(0,0,0,0.15));
}
.page-hero-inner { position: relative; z-index: 1; text-align: center; }
.page-hero-title { color: #fff; font-size: clamp(26px, 5vw, 40px); margin: 0 0 6px; }
.page-hero-sub { color: #fff; opacity: 0.9; margin: 0; }
.services-hero { background-image: url('images/world.png'); }
.about-hero { background-image: url('images/head.png'); }

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}
@media (max-width: 960px) {
  .card-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 560px) {
  .card-grid { grid-template-columns: 1fr; }
}
.card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
  text-align: left;
  padding: 0;
  cursor: pointer;
}
.card-media { position: relative; }
.card-media img { width: 100%; aspect-ratio: 16 / 9; object-fit: cover; background: #f0f0f0; display: block; }
.badge {
  position: absolute;
  left: 12px; bottom: 12px;
  background: rgba(10,127,68,0.9);
  color: #fff;
  padding: 4px 8px;
  border-radius: 999px;
  font-size: 12px;
}
.card { transition: transform 200ms ease, box-shadow 200ms ease; }
.card:hover { transform: translateY(-4px); box-shadow: 0 10px 26px rgba(0,0,0,0.08); }
.card-body { padding: 12px; }
.card h3 { margin: 0 0 6px; font-size: 18px; }
.card p { margin: 0; color: var(--muted); }
.card:focus, .card:hover { outline: none; box-shadow: 0 0 0 3px rgba(10,127,68,0.15); }

/* Detail panel */
.detail-panel {
  margin-top: 24px;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  background: #fff;
}
.detail-hero {
  position: relative;
  height: 220px;
  border-radius: 10px;
  overflow: hidden;
  margin-bottom: 12px;
  background-size: cover;
  background-position: center;
}
.detail-hero::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, rgba(0,0,0,0.25), rgba(0,0,0,0.05));
}
.detail-body { padding: 4px; }
.detail-panel h3 { margin-top: 0; }
.detail-panel p { margin: 0 0 12px; }
.detail-panel ul { margin: 0 0 12px 18px; }
.detail-panel li { margin-bottom: 6px; }

/* About */
.prose h3 { margin: 24px 0 8px; }
.prose p { margin: 0 0 12px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0;
  background: linear-gradient(180deg, #f2f2f2 0%, #ffffff 100%);
}
.footer-inner {
  display: flex; align-items: center; gap: 16px;
}
.footer-logo { height: 60px; width: auto; }
.footer-text { color: var(--muted); }
.services-preview { position: relative; }
.services-preview::before {
  content: "";
  position: absolute; inset: 0;
  background-image: url('images/world.png');
  background-size: cover; background-position: center;
  opacity: 0.12;
}
.services-preview .container { position: relative; z-index: 1; }
.long-cards {
  position: relative; z-index: 1;
  display: grid;
  grid-template-columns: 1fr; /* 移动端保持单列 */
  gap: 16px;
  padding: 0; /* 放入 container 后移除额外内边距以对齐版式 */
}
.long-card {
  position: relative;
  display: block;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
  text-decoration: none;
  height: 400px; /* 首页业务卡片统一高度 */
}
.long-card img { width: 100%; height: 100%; object-fit: cover; display: block; }
.long-card img { transition: transform 240ms ease; will-change: transform; }
.long-card:hover img { transform: scale(1.06); }
.long-card-title {
  position: absolute; left: 16px; bottom: 12px;
  background: rgba(0,0,0,0.6); color: #fff;
  padding: 6px 10px; border-radius: 8px; font-size: 14px;
}
.long-card:hover { box-shadow: 0 10px 26px rgba(0,0,0,0.08); transform: translateY(-2px); transition: 160ms ease; }

/* About preview */
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; align-items: center; }
@media (max-width: 800px) { .about-grid { grid-template-columns: 1fr; } }
.about-image img { width: 100%; border-radius: 12px; border: 1px solid var(--border); display: block; }
.about-brief p { margin: 0 0 12px; }
.about-brief { margin: 0; }
.about-brief p { line-height: 1.85; }
.btn {
  display: inline-block; text-decoration: none;
  background: var(--text); color: #fff; padding: 8px 14px;
  border-radius: 8px; font-size: 14px; border: 1px solid var(--text);
}
.btn:hover { opacity: 0.9; }

/* 图文交替段落（services 页面） */
.feature-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; align-items: center; }
@media (max-width: 900px) { .feature-grid { grid-template-columns: 1fr; } }
.feature-media { overflow: hidden; border-radius: 12px; }
.feature-media img { width: 100%; border-radius: 12px; border: 1px solid var(--border); display: block; transition: transform 240ms ease; will-change: transform; }
.feature-row:hover .feature-media img, .feature-media:hover img { transform: scale(1.03); }
.feature-copy h2 { margin: 0 0 8px; }
.feature-row.reverse .feature-grid { direction: rtl; }
.feature-row.reverse .feature-copy, .feature-row.reverse .feature-media { direction: ltr; }

/* 服务页：堆叠布局（标题-图片-内容） */
.feature-title { margin: 0 0 10px; font-size: 24px; }
.feature-row .container > .feature-media { margin-bottom: 14px; }

/* 关于页：补全产业链模块增加图片与文字间距 */
.chain-gap { gap: 32px; }
/* 兼容堆叠布局时增加上下间距 */
.chain-gap .feature-media { margin-bottom: 16px; }

/* 服务页：优点卡片化布局 */
.feature-items { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 8px; }
@media (max-width: 800px) { .feature-items { grid-template-columns: 1fr; } }
.feature-item { border: none; border-radius: 12px; padding: 12px; background: #fff; }
.feature-item h3 { margin: 0 0 8px; font-size: 16px; border-bottom: 1px solid var(--border); padding-bottom: 6px; }
.feature-item p { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.6; }
/* 品类图标样式 */
.feature-icon { color: var(--accent); text-align: center; }
/* 左大图标 + 右文字布局 */
.icon-row { display: grid; grid-template-columns: 56px 1fr; column-gap: 12px; align-items: start; }
.feature-text { min-width: 0; }

/* 轻量图标：使用 SVG 蒙版实现可配色的矢量图标 */
.icon-mask-base { display: inline-block; background-color: currentColor; }
.icon-mask-base { -webkit-mask-size: contain; mask-size: contain; -webkit-mask-repeat: no-repeat; mask-repeat: no-repeat; -webkit-mask-position: center; mask-position: center; }
/* 服务品类大图标尺寸（与原布局保持一致） */
.feature-icon-lg { width: 56px; height: 56px; }
/* 语言切换小图标尺寸 */
.lang-switch .icon-globe { width: 18px; height: 18px; }
/* 各具体图标：引用 images/icons 目录下的本地 SVG 作为蒙版 */
.icon-globe { -webkit-mask-image: url('images/icons/globe.svg'); mask-image: url('images/icons/globe.svg'); }
.icon-oil-can { -webkit-mask-image: url('images/icons/oil-can.svg'); mask-image: url('images/icons/oil-can.svg'); }
.icon-fire { -webkit-mask-image: url('images/icons/fire.svg'); mask-image: url('images/icons/fire.svg'); }
.icon-droplet { -webkit-mask-image: url('images/icons/droplet.svg'); mask-image: url('images/icons/droplet.svg'); }
.icon-truck { -webkit-mask-image: url('images/icons/truck.svg'); mask-image: url('images/icons/truck.svg'); }
.icon-gas-pump { -webkit-mask-image: url('images/icons/gas-pump.svg'); mask-image: url('images/icons/gas-pump.svg'); }
.icon-road { -webkit-mask-image: url('images/icons/road.svg'); mask-image: url('images/icons/road.svg'); }

/* LNG/LPG 介绍左右配图布局 */
.intro-row { display: flex; align-items: stretch; gap: 16px; margin: 0;  }
.intro-row .intro-media { flex: 1 1 0; }
.intro-row .intro-media img { width: 100%; object-fit: cover; display: block; }
.intro-row .intro-copy { flex: 1 1 0; min-width: 0; display: flex; flex-direction: column; justify-content: center; }
.intro-row.reverse { flex-direction: row-reverse; }
@media (max-width: 700px) {
  .intro-row { flex-direction: column; }
  .intro-row.reverse { flex-direction: column; }
  .intro-row .intro-media { flex: none; width: 100%; }
  .intro-row .intro-copy { flex: none; width: 100%; justify-content: flex-start; }
}

/* LNG/LPG 介绍标题加大字号 */
.intro-title { font-size: 22px; margin: 0 0 8px; }

/* LNG/LPG 统一背景与间距 */
.intro-group { display: flex; flex-direction: column; gap: 12px; margin: 30px 0; }

/* 统计条与数字 */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; align-items: start; }
@media (max-width: 900px) { .stats { grid-template-columns: 1fr 1fr; } }
@media (max-width: 560px) { .stats { grid-template-columns: 1fr; } }
.stat { display: flex; flex-direction: column; align-items: flex-start; gap: 4px; background: transparent; border: none; padding: 0; }
.stat-number { font-size: clamp(36px, 6vw, 56px); font-weight: 700; color: var(--accent); min-width: 2ch; }
.stat-number[data-plus="true"]::after { content: '+'; font-size: 0.7em; vertical-align: super; margin-left: 2px; }
.stat-suffix { color: var(--muted); }
.stat-label { color: var(--muted); }
.stat-band { background: linear-gradient(180deg, rgba(10,127,68,0.06), rgba(10,127,68,0)); }

/* 进入动画：淡入上移 */
.reveal { opacity: 0; transform: translateY(14px); transition: opacity 420ms ease, transform 420ms ease; }
.reveal.in { opacity: 1; transform: translateY(0); }

/* 关于我们页优势网格 */
.adv-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
@media (max-width: 900px) { .adv-grid { grid-template-columns: 1fr; } }
.adv-item { display: flex; align-items: center; gap: 12px; border: none; border-radius: 0; padding: 0; background: transparent; }
.adv-item img { display: none; }
.adv-item h3 { margin: 0 0 8px; font-size: 18px; border-bottom: 1px solid var(--border); padding-bottom: 6px; }

/* PC 端优化首页业务预览的大图尺寸 */
@media (min-width: 1024px) {
  /* 桌面端：一行四列 */
  .long-cards { grid-template-columns: repeat(4, 1fr); }
}