/* ============================================================
   OSO 绿色低碳科技 — 前台样式（绿色主题，响应式）
   ============================================================ */
:root {
  --primary: #0e7a5f;
  --primary-dark: #0a5c48;
  --primary-deeper: #064e3b;
  --primary-light: #e8f5f0;
  --accent: #22c55e;
  --accent-dark: #16a34a;
  --gold: #f59e0b;
  --ink: #1f2937;
  --muted: #6b7280;
  --bg: #ffffff;
  --bg-soft: #f4faf7;
  --border: #e6ebe9;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 12px 34px rgba(10, 92, 72, .09);
  --shadow-sm: 0 4px 14px rgba(10, 92, 72, .08);
  --maxw: 1200px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }
img { max-width: 100%; display: block; }
button, input, textarea, select { font: inherit; }

.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.section { padding: 76px 0; }
.section--soft { background: var(--bg-soft); }

/* ---------- 通用组件 ---------- */
.eyebrow {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; font-weight: 600; letter-spacing: .12em;
  color: var(--primary); text-transform: uppercase;
}
.eyebrow::before { content: ''; width: 22px; height: 2px; background: var(--accent); border-radius: 2px; }

.section-head { max-width: 720px; margin: 0 auto 46px; text-align: center; }
.section-head h2 { font-size: 34px; line-height: 1.25; margin: 14px 0 14px; color: var(--ink); }
.section-head p { color: var(--muted); font-size: 16px; }

.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  padding: 12px 26px; border-radius: 999px; font-weight: 600; font-size: 15px;
  cursor: pointer; border: 1px solid transparent; transition: all .22s ease; white-space: nowrap;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); transform: translateY(-2px); box-shadow: var(--shadow-sm); }
.btn-accent { background: var(--accent); color: #fff; }
.btn-accent:hover { background: var(--accent-dark); transform: translateY(-2px); }
.btn-outline { border-color: rgba(255,255,255,.55); color: #fff; }
.btn-outline:hover { background: rgba(255,255,255,.14); }
.btn-ghost { border-color: var(--primary); color: var(--primary); }
.btn-ghost:hover { background: var(--primary-light); }

.tag {
  display: inline-block; padding: 4px 12px; border-radius: 999px;
  font-size: 12px; font-weight: 600; background: var(--primary-light); color: var(--primary);
}

/* ---------- 顶栏 ---------- */
.topbar {
  background: var(--primary-deeper); color: rgba(255,255,255,.9);
  font-size: 13px;
}
.topbar .container { display: flex; align-items: center; justify-content: space-between; height: 40px; }
.topbar .tb-left { display: flex; gap: 22px; }
.topbar a:hover { color: #fff; }
.topbar .tb-right a { margin-left: 18px; }

/* ---------- 头部导航 ---------- */
.site-header { position: sticky; top: 0; z-index: 100; background: #fff; box-shadow: 0 1px 0 var(--border); }
.site-header .container { display: flex; align-items: center; justify-content: space-between; height: 72px; }
.brand { display: flex; align-items: center; gap: 12px; }
.brand .logo-mark {
  width: 44px; height: 44px; border-radius: 12px; flex: none;
  background: linear-gradient(135deg, var(--accent), var(--primary));
  display: flex; align-items: center; justify-content: center; color: #fff;
}
.brand .logo-mark svg { width: 26px; height: 26px; }
.brand .logo-mark img { width: 100%; height: 100%; object-fit: contain; border-radius: 12px; }
.brand .brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand .brand-text b { font-size: 18px; color: var(--ink); letter-spacing: .02em; }
.brand .brand-text span { font-size: 11px; color: var(--muted); letter-spacing: .06em; }

.main-nav { display: flex; align-items: center; gap: 4px; }
.main-nav a {
  padding: 10px 16px; border-radius: 8px; font-size: 15px; font-weight: 500; color: #374151;
  transition: all .18s ease;
}
.main-nav a:hover { color: var(--primary); background: var(--primary-light); }
.main-nav a.active { color: var(--primary); font-weight: 700; }
.main-nav .nav-cta { margin-left: 10px; }

.nav-toggle { display: none; background: none; border: 0; cursor: pointer; color: var(--ink); }
.nav-toggle svg { width: 28px; height: 28px; }

/* ---------- Hero 轮播 ---------- */
.hero { position: relative; overflow: hidden; user-select: none; -webkit-user-select: none; }
.hero-slide {
  position: relative; min-height: 520px; display: flex; align-items: center;
  color: #fff; transition: opacity .6s ease;
}
.hero-slide .container { position: relative; z-index: 2; padding-top: 70px; padding-bottom: 70px; }
.hero-slide .hero-tag {
  display: inline-block; padding: 6px 16px; border-radius: 999px; font-size: 13px; font-weight: 600;
  background: rgba(255,255,255,.16); border: 1px solid rgba(255,255,255,.3); backdrop-filter: blur(4px);
  margin-bottom: 18px;
}
.hero-slide h1 { font-size: 46px; line-height: 1.2; font-weight: 800; max-width: 720px; margin-bottom: 16px; }
.hero-slide .hero-sub { font-size: 20px; font-weight: 600; color: rgba(255,255,255,.92); margin-bottom: 10px; }
.hero-slide .hero-desc { font-size: 16px; color: rgba(255,255,255,.82); max-width: 560px; margin-bottom: 28px; }
.hero-slide .hero-actions { display: flex; gap: 14px; }

.hero-theme-forest { background: radial-gradient(1100px 600px at 85% -10%, #2fbf8f 0%, transparent 55%), linear-gradient(120deg, #06321f 0%, #0a5c48 55%, #0e7a5f 100%); }
.hero-theme-teal   { background: radial-gradient(1000px 600px at 80% -10%, #38c9a8 0%, transparent 55%), linear-gradient(120deg, #04323a 0%, #0b5f6b 55%, #12898c 100%); }
.hero-theme-moss   { background: radial-gradient(1000px 600px at 85% -10%, #a3d977 0%, transparent 55%), linear-gradient(120deg, #1d3a1a 0%, #3c6b2f 60%, #4f8a3c 100%); }

.hero-pattern {
  position: absolute; inset: 0; opacity: .14; z-index: 1; pointer-events: none;
  background-image: radial-gradient(rgba(255,255,255,.5) 1px, transparent 1px);
  background-size: 26px 26px;
}
.hero-dots { position: absolute; bottom: 26px; left: 50%; transform: translateX(-50%); z-index: 3; display: flex; gap: 8px; }
.hero-dots button { width: 10px; height: 10px; border-radius: 999px; border: 0; background: rgba(255,255,255,.4); cursor: pointer; padding: 0; transition: all .2s; }
.hero-dots button.active { width: 28px; background: #fff; }
.hero-arrow { position: absolute; top: 50%; transform: translateY(-50%); z-index: 3; width: 46px; height: 46px; border-radius: 50%; border: 0; background: rgba(0,0,0,.25); color: #fff; font-size: 28px; line-height: 1; cursor: pointer; display: flex; align-items: center; justify-content: center; transition: all .2s; }
.hero-arrow:hover { background: rgba(0,0,0,.45); }
.hero-prev { left: 20px; }
.hero-next { right: 20px; }

/* ---------- 数据统计 ---------- */
.stats-strip { background: #fff; margin-top: -54px; position: relative; z-index: 5; border-radius: var(--radius); box-shadow: var(--shadow); }
.stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); }
.stat-item { padding: 30px 20px; text-align: center; border-right: 1px solid var(--border); }
.stat-item:last-child { border-right: 0; }
.stat-item b { display: block; font-size: 34px; font-weight: 800; color: var(--primary); line-height: 1; }
.stat-item span { color: var(--muted); font-size: 14px; }

/* ---------- 卡片 ---------- */
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 22px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 24px; }

.card { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 30px; transition: all .25s ease; }
.card:hover { transform: translateY(-5px); box-shadow: var(--shadow); border-color: transparent; }

.icon-badge {
  width: 56px; height: 56px; border-radius: 14px; display: flex; align-items: center; justify-content: center;
  background: var(--primary-light); color: var(--primary); margin-bottom: 20px;
}
.icon-badge svg { width: 28px; height: 28px; }

.service-card .card-title { font-size: 20px; font-weight: 700; margin-bottom: 8px; }
.service-card .card-tagline { font-size: 13px; color: var(--accent-dark); font-weight: 600; margin-bottom: 12px; }
.service-card .card-desc { color: var(--muted); font-size: 14.5px; margin-bottom: 18px; }
.service-card .card-link { font-weight: 600; color: var(--primary); font-size: 14.5px; display: inline-flex; align-items: center; gap: 6px; }
.service-card .card-link:hover { gap: 10px; }

.advantage-card .card-title { font-size: 17px; font-weight: 700; margin-bottom: 8px; }

/* ---------- 新闻 / 案例 ---------- */
.news-item { display: flex; gap: 20px; padding: 20px 0; border-bottom: 1px dashed var(--border); }
.news-item:last-child { border-bottom: 0; }
.news-date { flex: none; width: 64px; text-align: center; }
.news-date .d { font-size: 26px; font-weight: 800; color: var(--primary); line-height: 1; }
.news-date .m { font-size: 12px; color: var(--muted); }
.news-body h4 { font-size: 17px; font-weight: 600; margin-bottom: 6px; }
.news-body h4 a:hover { color: var(--primary); }
.news-body p { color: var(--muted); font-size: 14px; }

.case-card { overflow: hidden; padding: 0; display: flex; flex-direction: column; }
.case-cover {
  height: 170px; display: flex; align-items: center; justify-content: center; color: #fff;
  font-size: 40px; font-weight: 800; letter-spacing: .02em;
}
.case-body { padding: 24px; display: flex; flex-direction: column; flex: 1; }
.case-body h4 { font-size: 18px; font-weight: 700; margin-bottom: 8px; }
.case-meta { font-size: 13px; color: var(--muted); margin-bottom: 10px; }
.case-body p { color: var(--muted); font-size: 14px; flex: 1; margin-bottom: 16px; }
.case-tags { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }

/* ---------- 产品系统 ---------- */
.prod-card { overflow: hidden; padding: 0; display: flex; flex-direction: column; }
.prod-cover { height: 120px; display: flex; align-items: center; justify-content: center; color: #fff; }
.prod-cover svg { width: 44px; height: 44px; opacity: .92; }
.prod-body { padding: 24px; display: flex; flex-direction: column; flex: 1; }
.prod-body h4 { font-size: 18px; font-weight: 700; margin-bottom: 4px; }
.prod-subtitle { font-size: 13px; color: var(--accent-dark); font-weight: 600; margin-bottom: 10px; }
.prod-body p { color: var(--muted); font-size: 14px; flex: 1; margin-bottom: 16px; }
.prod-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.prod-actions .btn { padding: 9px 16px; font-size: 14px; }

/* ---------- 服务详情 ---------- */
.page-hero { background: linear-gradient(120deg, var(--primary-deeper), var(--primary)); color: #fff; padding: 66px 0; }
.page-hero h1 { font-size: 38px; font-weight: 800; margin-bottom: 12px; }
.page-hero p { color: rgba(255,255,255,.85); max-width: 720px; font-size: 16px; }
.crumb { font-size: 13px; color: rgba(255,255,255,.75); margin-bottom: 16px; }
.crumb a:hover { color: #fff; }

.layout { display: grid; grid-template-columns: 320px 1fr; gap: 32px; align-items: start; }
.side-nav { position: sticky; top: 100px; background: #fff; border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden; }
.side-nav h3 { padding: 18px 20px; background: var(--primary); color: #fff; font-size: 16px; }
.side-nav a { display: flex; align-items: center; justify-content: space-between; padding: 14px 20px; border-bottom: 1px solid var(--border); color: #374151; font-size: 15px; transition: all .18s; }
.side-nav a:last-child { border-bottom: 0; }
.side-nav a:hover { background: var(--primary-light); color: var(--primary); }
.side-nav a.active { background: var(--primary-light); color: var(--primary); font-weight: 700; }

.content-panel { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 36px; }
.content-panel .prose { font-size: 16px; color: #374151; }
.prose h3 { font-size: 20px; margin: 26px 0 12px; color: var(--ink); padding-left: 12px; border-left: 4px solid var(--accent); }
.prose p { margin-bottom: 14px; }
.prose ul { padding-left: 4px; }
.prose li { position: relative; padding-left: 22px; margin-bottom: 8px; }
.prose li::before { content: '✓'; position: absolute; left: 0; top: 1px; color: var(--accent-dark); font-weight: 700; }
.prose img { max-width: 100%; height: auto; border-radius: 8px; margin: 8px 0; }

.block-title { font-size: 18px; font-weight: 700; margin: 8px 0 16px; }

/* 流程步骤 */
.steps { display: grid; gap: 14px; }
.step { display: flex; gap: 16px; background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius-sm); padding: 18px 20px; }
.step .step-no { flex: none; width: 40px; height: 40px; border-radius: 50%; background: var(--primary); color: #fff; display: flex; align-items: center; justify-content: center; font-weight: 800; }
.step h5 { font-size: 16px; font-weight: 700; margin-bottom: 4px; }
.step p { color: var(--muted); font-size: 14px; }

/* FAQ */
.faq-item { border: 1px solid var(--border); border-radius: var(--radius-sm); margin-bottom: 12px; overflow: hidden; }
.faq-q { padding: 16px 20px; font-weight: 600; cursor: pointer; display: flex; justify-content: space-between; align-items: center; background: #fff; }
.faq-q:hover { color: var(--primary); }
.faq-q::after { content: '+'; font-size: 22px; color: var(--primary); }
.faq-item.open .faq-q::after { content: '−'; }
.faq-a { padding: 0 20px; max-height: 0; overflow: hidden; transition: all .25s ease; color: var(--muted); }
.faq-item.open .faq-a { padding: 0 20px 18px; max-height: 300px; }

/* ---------- 关于 ---------- */
.about-intro { display: grid; grid-template-columns: 1.1fr 1fr; gap: 48px; align-items: center; }
.about-intro .lead { font-size: 17px; color: #374151; }
.about-intro p { margin-bottom: 14px; color: var(--muted); }
.about-visual { border-radius: var(--radius); background: linear-gradient(135deg, var(--accent), var(--primary)); color: #fff; padding: 40px; min-height: 320px; display: flex; flex-direction: column; justify-content: center; }
.about-visual b { font-size: 28px; margin-bottom: 14px; }
.about-visual p { color: rgba(255,255,255,.92); }

.qual-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 22px; }

/* ---------- 联系 ---------- */
.contact-grid { display: grid; grid-template-columns: 1fr 1.3fr; gap: 32px; }
.contact-info .info-item { display: flex; gap: 16px; padding: 18px 0; border-bottom: 1px dashed var(--border); }
.contact-info .info-item:last-child { border-bottom: 0; }
.contact-info .info-icon { flex: none; width: 46px; height: 46px; border-radius: 12px; background: var(--primary-light); color: var(--primary); display: flex; align-items: center; justify-content: center; }
.contact-info .info-icon svg { width: 22px; height: 22px; }
.contact-info h5 { font-size: 15px; margin-bottom: 4px; }
.contact-info p { color: var(--muted); font-size: 14.5px; }

.form-panel { background: #fff; border: 1px solid var(--border); border-radius: var(--radius); padding: 34px; box-shadow: var(--shadow-sm); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
.field { margin-bottom: 16px; }
.field label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 7px; }
.field input, .field textarea, .field select {
  width: 100%; padding: 12px 14px; border: 1px solid var(--border); border-radius: var(--radius-sm);
  outline: none; transition: border .18s; background: #fff; color: var(--ink);
}
.field input:focus, .field textarea:focus, .field select:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(14,122,95,.12); }
.field textarea { resize: vertical; min-height: 120px; }
.form-note { font-size: 13px; color: var(--muted); margin-top: 10px; }
.form-success { display: none; padding: 14px 16px; border-radius: var(--radius-sm); background: var(--primary-light); color: var(--primary-dark); font-weight: 600; margin-bottom: 16px; }

/* ---------- 页脚（参考 bfb.cn：链接分栏 + 关注我们 + 联系 + 版权） ---------- */
.site-footer { background: var(--primary-deeper); color: rgba(255,255,255,.72); }
.site-footer .footer-nav { display: flex; justify-content: space-between; gap: 32px; padding: 52px 0 36px; }
.site-footer .fn-col { flex: 1 1 0; min-width: 0; }
.site-footer .fn-follow { flex: 1.4 1 0; }
.site-footer h4 { color: #fff; font-size: 16px; font-weight: 700; margin-bottom: 18px; }
.site-footer .fn-col li { margin-bottom: 10px; }
.site-footer .fn-col a { color: rgba(255,255,255,.7); font-size: 14px; transition: color .15s; }
.site-footer .fn-col a:hover { color: #fff; }
.site-footer .fn-phone { display: flex; align-items: center; gap: 8px; margin-bottom: 10px; font-size: 16px; font-weight: 600; }
.site-footer .fn-phone a { color: #fff; font-size: 16px; }
.site-footer .fn-phone svg { color: var(--accent); }
.site-footer .fn-wechat { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; font-size: 14px; color: rgba(255,255,255,.7); }
.site-footer .fn-wechat svg { color: var(--accent); }
.site-footer .fn-slogan { font-size: 13px; color: rgba(255,255,255,.55); line-height: 1.7; }
.site-footer .fn-qr { margin-bottom: 10px; }
.site-footer .fn-qr img { width: 96px; height: 96px; object-fit: contain; border-radius: 8px; background: #fff; padding: 4px; }
.site-footer .footer-links { display: flex; flex-wrap: wrap; align-items: center; padding: 14px 0; border-bottom: 1px solid rgba(255,255,255,.1); font-size: 13px; color: rgba(255,255,255,.6); }
.site-footer .footer-links span { color: rgba(255,255,255,.5); margin-right: 8px; }
.site-footer .footer-links a { color: rgba(255,255,255,.6); margin-right: 14px; }
.site-footer .footer-links a:hover { color: #fff; }
.site-footer .footer-bottom { border-top: 1px solid rgba(255,255,255,.12); padding: 18px 0; }
.site-footer .footer-bottom .container { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; font-size: 13px; color: rgba(255,255,255,.6); }
.site-footer .fb-contact { display: flex; gap: 20px; flex-wrap: wrap; }
.site-footer .fb-contact span { display: inline-flex; align-items: center; gap: 6px; }
.site-footer .fb-contact svg { width: 15px; height: 15px; color: var(--accent); }
.site-footer .fb-copy a { color: rgba(255,255,255,.6); }
.site-footer .fb-copy a:hover { color: #fff; }

/* ---------- 返回顶部 ---------- */
.to-top {
  position: fixed; right: 24px; bottom: 24px; width: 46px; height: 46px; border-radius: 50%;
  background: var(--primary); color: #fff; border: 0; cursor: pointer; display: none;
  align-items: center; justify-content: center; box-shadow: var(--shadow-sm); z-index: 90;
}
.to-top.show { display: flex; }

/* ---------- 空状态 ---------- */
.empty { text-align: center; padding: 60px 20px; color: var(--muted); }
.empty svg { width: 60px; height: 60px; opacity: .3; margin-bottom: 14px; }

/* ---------- 响应式 ---------- */
@media (max-width: 992px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .stats-grid { grid-template-columns: repeat(2, 1fr); }
  .stat-item:nth-child(2) { border-right: 0; }
  .layout { grid-template-columns: 1fr; }
  .side-nav { position: static; }
  .about-intro, .contact-grid { grid-template-columns: 1fr; }
  .site-footer .footer-nav { flex-wrap: wrap; gap: 28px; }
  .site-footer .fn-col { flex: 1 1 30%; }
  .hero-slide h1 { font-size: 34px; }
}

@media (max-width: 640px) {
  body { overflow-x: hidden; }
  .container { padding: 0 18px; }
  .section { padding: 48px 0; }
  .section-head { margin-bottom: 32px; }
  .section-head h2 { font-size: 25px; }
  .grid-3, .grid-4, .grid-2, .qual-grid { grid-template-columns: 1fr; }
  .form-row { grid-template-columns: 1fr; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .stats-strip { margin-top: -40px; }
  .stat-item { padding: 22px 12px; }
  .stat-item b { font-size: 26px; }
  .stat-item span { font-size: 13px; }
  .site-footer .footer-nav { display: none; }
  .site-footer .footer-links { display: none; }
  .site-footer .fb-contact { display: none; }
  .site-footer .footer-bottom .container { flex-direction: column; align-items: center; text-align: center; gap: 8px; }
  .main-nav {
    position: absolute; top: 72px; left: 0; right: 0; background: #fff; flex-direction: column;
    align-items: stretch; padding: 12px; box-shadow: var(--shadow); display: none; border-top: 1px solid var(--border);
  }
  .main-nav.open { display: flex; }
  .main-nav a { padding: 13px 16px; }
  .main-nav .nav-cta { margin-left: 0; }
  .nav-toggle { display: block; }
  .hero-slide { min-height: 430px; }
  .hero-arrow { width: 38px; height: 38px; font-size: 22px; }
  .hero-prev { left: 8px; }
  .hero-next { right: 8px; }
  .hero-slide h1 { font-size: 26px; }
  .hero-slide .hero-sub { font-size: 16px; }
  .hero-slide .hero-desc { font-size: 14.5px; }
  .hero-slide .hero-actions { flex-wrap: wrap; }
  .hero-slide .hero-actions .btn { padding: 11px 20px; font-size: 14px; }
  .page-hero { padding: 44px 0; }
  .page-hero h1 { font-size: 27px; }
  .page-hero p { font-size: 14.5px; }
  .content-panel { padding: 22px; }
  .step { flex-direction: column; gap: 10px; }
  .about-visual { min-height: auto; padding: 26px; }
  .about-visual b { font-size: 21px; }
  .case-cover { height: 140px; }
  .news-item { flex-direction: column; gap: 8px; }
  .news-date { width: auto; display: flex; align-items: baseline; gap: 6px; }
  .news-date .d { font-size: 20px; }
  .contact-grid { gap: 22px; }
  .form-panel { padding: 22px; }
  .to-top { right: 14px; bottom: 14px; width: 42px; height: 42px; }
  .topbar .tb-left { display: none; }
}