/* ===== TreeUp 树腾新材料 · 基础重置 ===== */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: #fff;
  line-height: 1.75;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }
ul { list-style: none; margin: 0; padding: 0; }
h1, h2, h3, h4 { margin: 0; font-weight: 700; line-height: 1.35; }
p { margin: 0; }
button { font-family: inherit; }

/* ===== 设计变量 ===== */
:root {
  --brand: #0B4FA0;
  --brand-dark: #083A78;
  --brand-light: #E8F1FC;
  --accent: #00A5C8;
  --accent-orange: #F58220;
  --text: #26313D;
  --text-sub: #6A7684;
  --line: #E4E9F0;
  --bg-soft: #F5F8FC;
  --white: #fff;
  --radius: 10px;
  --shadow: 0 6px 24px rgba(11, 79, 160, .08);
  --shadow-hover: 0 14px 36px rgba(11, 79, 160, .16);
  --maxw: 1200px;
}

/* ===== 布局工具 ===== */
.container { width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 0 24px; }
.section { padding: 76px 0; }
.section--soft { background: var(--bg-soft); }
.section-head { text-align: center; margin-bottom: 48px; }
.section-head .eyebrow {
  display: inline-block; font-size: 13px; letter-spacing: 2px; text-transform: uppercase;
  color: var(--accent); font-weight: 700; margin-bottom: 10px;
}
.section-head h2 { font-size: 32px; color: var(--brand-dark); }
.section-head h2::after {
  content: ""; display: block; width: 56px; height: 3px; background: var(--accent-orange);
  margin: 16px auto 0; border-radius: 2px;
}
.section-head p { color: var(--text-sub); margin-top: 14px; font-size: 15px; }

/* ===== 按钮 ===== */
.btn {
  display: inline-flex; align-items: center; gap: 8px; justify-content: center;
  padding: 12px 26px; border-radius: 6px; font-size: 15px; font-weight: 600;
  border: 1px solid transparent; cursor: pointer; transition: .25s;
}
.btn-primary { background: var(--brand); color: #fff; }
.btn-primary:hover { background: var(--brand-dark); transform: translateY(-2px); box-shadow: var(--shadow-hover); }
.btn-ghost { border-color: #fff; color: #fff; }
.btn-ghost:hover { background: #fff; color: var(--brand); }
.btn-accent { background: var(--accent-orange); color: #fff; }
.btn-accent:hover { filter: brightness(1.08); transform: translateY(-2px); }
.btn-outline { border-color: var(--brand); color: var(--brand); background: transparent; }
.btn-outline:hover { background: var(--brand); color: #fff; }

/* ===== 顶部信息条 ===== */
.topbar { background: var(--brand-dark); color: #cfe0f5; font-size: 13px; }
.topbar .container { display: flex; align-items: center; justify-content: space-between; gap: 20px; min-height: 38px; flex-wrap: wrap; }
.topbar span { display: inline-flex; align-items: center; gap: 6px; }
.topbar svg { opacity: .8; }

/* ===== 导航 ===== */
.navbar {
  position: sticky; top: 0; z-index: 100; background: #fff;
  border-bottom: 1px solid var(--line); transition: box-shadow .25s;
}
.navbar.is-sticky { box-shadow: 0 4px 18px rgba(0,0,0,.07); }
.navbar .container { display: flex; align-items: center; justify-content: space-between; min-height: 72px; gap: 24px; }
.logo { display: flex; align-items: center; gap: 11px; }
.logo-mark {
  width: 42px; height: 42px; border-radius: 9px; flex: none;
  background: linear-gradient(135deg, var(--brand), var(--accent));
  display: grid; place-items: center;
}
.logo-text strong { display: block; font-size: 20px; color: var(--brand-dark); letter-spacing: .5px; line-height: 1.1; }
.logo-text span { display: block; font-size: 12px; color: var(--text-sub); letter-spacing: 1.5px; }
.nav-menu { display: flex; align-items: center; gap: 6px; }
.nav-menu a {
  padding: 10px 15px; font-size: 15px; font-weight: 500; color: var(--text);
  border-radius: 6px; position: relative; transition: .2s;
}
.nav-menu a::after {
  content: ""; position: absolute; left: 15px; right: 15px; bottom: 2px; height: 2px;
  background: var(--accent-orange); transform: scaleX(0); transition: .25s;
}
.nav-menu a:hover { color: var(--brand); }
.nav-menu a:hover::after, .nav-menu a.active::after { transform: scaleX(1); }
.nav-menu a.active { color: var(--brand); font-weight: 600; }
.nav-toggle { display: none; background: none; border: 0; cursor: pointer; padding: 8px; }

/* ===== Hero ===== */
.hero {
  position: relative; color: #fff; overflow: hidden;
  background: linear-gradient(120deg, #052A56 0%, var(--brand-dark) 40%, var(--brand) 100%);
}
.hero::before {
  content: ""; position: absolute; inset: 0;
  background-image: radial-gradient(circle at 20% 30%, rgba(0,165,200,.35), transparent 55%),
                    radial-gradient(circle at 85% 70%, rgba(245,130,32,.28), transparent 50%);
}
.hero::after {
  content: ""; position: absolute; inset: 0; opacity: .16;
  background-image: linear-gradient(rgba(255,255,255,.5) 1px, transparent 1px),
                    linear-gradient(90deg, rgba(255,255,255,.5) 1px, transparent 1px);
  background-size: 46px 46px;
}
.hero .container { position: relative; z-index: 2; padding: 96px 24px 88px; }
.hero-grid { display: grid; grid-template-columns: 1.1fr .9fr; gap: 56px; align-items: center; }
.hero h1 { font-size: 44px; line-height: 1.25; margin-bottom: 20px; font-weight: 800; }
.hero h1 em { font-style: normal; color: #FFC68A; }
.hero-lead { font-size: 16.5px; color: #D7E6F8; margin-bottom: 30px; max-width: 560px; }
.hero-tags { display: flex; flex-wrap: wrap; gap: 10px; margin-bottom: 32px; }
.hero-tags span {
  background: rgba(255,255,255,.13); border: 1px solid rgba(255,255,255,.25);
  padding: 5px 13px; border-radius: 40px; font-size: 13px;
}
.hero-actions { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-card {
  background: rgba(255,255,255,.1); backdrop-filter: blur(8px);
  border: 1px solid rgba(255,255,255,.22); border-radius: 14px; padding: 26px;
}
.hero-card h3 { font-size: 17px; margin-bottom: 18px; display: flex; align-items: center; gap: 8px; }
.hero-card li {
  display: flex; justify-content: space-between; gap: 14px; padding: 11px 0;
  border-bottom: 1px dashed rgba(255,255,255,.2); font-size: 14px;
}
.hero-card li:last-child { border-bottom: 0; }
.hero-card li b { color: #FFC68A; font-variant-numeric: tabular-nums; }

/* ===== 数据条 ===== */
.stats { background: var(--bg-soft); border-bottom: 1px solid var(--line); }
.stats .container { display: grid; grid-template-columns: repeat(4, 1fr); padding: 0 24px; }
.stat { text-align: center; padding: 34px 12px; border-right: 1px solid var(--line); }
.stat:last-child { border-right: 0; }
.stat strong { display: block; font-size: 34px; color: var(--brand); font-weight: 800; line-height: 1.1; }
.stat strong i { font-style: normal; font-size: 18px; margin-left: 2px; }
.stat span { font-size: 13.5px; color: var(--text-sub); }

/* ===== 通用卡片网格 ===== */
.grid { display: grid; gap: 26px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

/* 优势卡 */
.feature {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 30px 26px; transition: .28s;
}
.feature:hover { transform: translateY(-6px); box-shadow: var(--shadow); border-color: #cddff5; }
.feature-icon {
  width: 52px; height: 52px; border-radius: 12px; background: var(--brand-light);
  display: grid; place-items: center; margin-bottom: 18px;
}
.feature h3 { font-size: 18px; color: var(--brand-dark); margin-bottom: 10px; }
.feature p { color: var(--text-sub); font-size: 14.5px; }

/* 产品卡 */
.product-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden; display: flex; flex-direction: column; transition: .28s;
}
.product-card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }
.product-thumb {
  height: 150px; display: grid; place-items: center; color: #fff;
  background: linear-gradient(135deg, var(--brand), var(--accent));
}
.product-thumb svg { opacity: .92; }
.product-body { padding: 22px; flex: 1; display: flex; flex-direction: column; }
.product-body h3 { font-size: 17px; color: var(--brand-dark); margin-bottom: 8px; }
.product-body p { color: var(--text-sub); font-size: 14px; flex: 1; }
.product-meta {
  margin-top: 16px; padding-top: 14px; border-top: 1px dashed var(--line);
  font-size: 13px; color: var(--text-sub); display: grid; gap: 5px;
}
.product-meta div { display: flex; justify-content: space-between; gap: 12px; }
.product-meta b { color: var(--text); font-weight: 600; }
.product-link { margin-top: 16px; color: var(--brand); font-size: 14px; font-weight: 600; }
.product-link:hover { color: var(--accent-orange); }

/* 应用领域 */
.app-row { display: grid; grid-template-columns: 1fr 1fr; gap: 46px; align-items: center; margin-bottom: 56px; }
.app-row:last-child { margin-bottom: 0; }
.app-row:nth-child(even) .app-visual { order: -1; }
.app-visual {
  border-radius: 14px; min-height: 250px; color: #fff; padding: 34px;
  display: flex; flex-direction: column; justify-content: flex-end;
  box-shadow: var(--shadow);
}
.app-visual h4 { font-size: 20px; margin-bottom: 6px; }
.app-visual span { font-size: 14px; opacity: .85; }
.v1 { background: linear-gradient(135deg, #0B4FA0, #00A5C8); }
.v2 { background: linear-gradient(135deg, #F58220, #C2571A); }
.v3 { background: linear-gradient(135deg, #10794F, #3DBE86); }
.v4 { background: linear-gradient(135deg, #5B3FA8, #9277E0); }
.v5 { background: linear-gradient(135deg, #12456B, #2E86AB); }
.app-text h3 { font-size: 24px; color: var(--brand-dark); margin-bottom: 14px; }
.app-text p { color: var(--text-sub); margin-bottom: 18px; }
.app-list li { position: relative; padding-left: 22px; margin-bottom: 9px; font-size: 15px; }
.app-list li::before {
  content: ""; position: absolute; left: 0; top: 11px; width: 8px; height: 8px;
  border-radius: 50%; background: var(--accent-orange);
}

/* 流程 */
.steps { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; }
.step { text-align: center; position: relative; }
.step-num {
  width: 54px; height: 54px; margin: 0 auto 14px; border-radius: 50%;
  display: grid; place-items: center; background: #fff; border: 2px solid var(--brand);
  color: var(--brand); font-weight: 800; font-size: 18px;
}
.step h4 { font-size: 16px; color: var(--brand-dark); margin-bottom: 6px; }
.step p { font-size: 13.5px; color: var(--text-sub); }

/* 新闻 */
.news-card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  overflow: hidden; transition: .28s; display: flex; flex-direction: column;
}
.news-card:hover { box-shadow: var(--shadow); transform: translateY(-5px); }
.news-date {
  background: linear-gradient(135deg, var(--brand), var(--accent)); color: #fff;
  padding: 14px 22px; font-size: 13px; display: flex; justify-content: space-between; align-items: center;
}
.news-body { padding: 22px; flex: 1; display: flex; flex-direction: column; }
.news-body h3 { font-size: 16.5px; color: var(--brand-dark); margin-bottom: 10px; }
.news-body p { font-size: 14px; color: var(--text-sub); flex: 1; }
.news-more { margin-top: 14px; font-size: 14px; color: var(--brand); font-weight: 600; }

/* CTA 条 */
.cta-band {
  background: linear-gradient(110deg, var(--brand-dark), var(--brand) 60%, var(--accent));
  color: #fff; padding: 52px 0;
}
.cta-band .container { display: flex; align-items: center; justify-content: space-between; gap: 30px; flex-wrap: wrap; }
.cta-band h2 { font-size: 27px; margin-bottom: 8px; }
.cta-band p { color: #DCE9F8; font-size: 15px; }

/* 面包屑 */
.breadcrumb { background: var(--bg-soft); border-bottom: 1px solid var(--line); padding: 26px 0; }
.breadcrumb h1 { font-size: 28px; color: var(--brand-dark); margin-bottom: 6px; }
.breadcrumb p { color: var(--text-sub); font-size: 14px; }
.crumb { font-size: 13px; color: var(--text-sub); margin-bottom: 10px; }
.crumb a:hover { color: var(--brand); }

/* 表格 */
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; }
table { width: 100%; border-collapse: collapse; font-size: 14.5px; min-width: 680px; }
th, td { padding: 14px 18px; text-align: left; border-bottom: 1px solid var(--line); }
thead th { background: var(--brand); color: #fff; font-weight: 600; white-space: nowrap; }
tbody tr:last-child td { border-bottom: 0; }
tbody tr:hover { background: var(--brand-light); }
td b { color: var(--brand-dark); }

/* 筛选按钮 */
.filters { display: flex; flex-wrap: wrap; gap: 10px; justify-content: center; margin-bottom: 40px; }
.filter-btn {
  padding: 9px 20px; border-radius: 40px; border: 1px solid var(--line); background: #fff;
  color: var(--text); font-size: 14.5px; cursor: pointer; transition: .22s;
}
.filter-btn:hover { border-color: var(--brand); color: var(--brand); }
.filter-btn.active { background: var(--brand); border-color: var(--brand); color: #fff; }
.filter-item[hidden] { display: none; }

/* 关于我们 */
.about-intro { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; align-items: center; }
.about-intro h2 { font-size: 28px; color: var(--brand-dark); margin-bottom: 16px; }
.about-intro p { color: var(--text-sub); margin-bottom: 14px; }
.about-visual {
  border-radius: 14px; padding: 44px 34px; color: #fff; min-height: 300px;
  background: linear-gradient(135deg, var(--brand-dark), var(--accent));
  display: flex; flex-direction: column; justify-content: center; gap: 18px;
  box-shadow: var(--shadow);
}
.about-visual h3 { font-size: 22px; }
.about-visual li { display: flex; gap: 12px; align-items: flex-start; font-size: 14.5px; }

.timeline { position: relative; padding-left: 34px; }
.timeline::before { content: ""; position: absolute; left: 9px; top: 6px; bottom: 6px; width: 2px; background: var(--line); }
.tl-item { position: relative; padding-bottom: 30px; }
.tl-item::before {
  content: ""; position: absolute; left: -30px; top: 6px; width: 12px; height: 12px;
  border-radius: 50%; background: var(--accent-orange); border: 2px solid #fff; box-shadow: 0 0 0 3px var(--brand-light);
}
.tl-item strong { display: block; color: var(--brand); font-size: 15px; }
.tl-item p { color: var(--text-sub); font-size: 14.5px; }

.values { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.value-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 26px 22px; text-align: center; }
.value-card .k { font-size: 22px; color: var(--brand); font-weight: 800; margin-bottom: 8px; }
.value-card p { font-size: 14px; color: var(--text-sub); }

.certs { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.cert {
  border: 1px dashed #B9CCE6; border-radius: var(--radius); padding: 26px 18px; text-align: center;
  background: #fff; transition: .25s;
}
.cert:hover { border-color: var(--brand); box-shadow: var(--shadow); }
.cert h4 { font-size: 15.5px; color: var(--brand-dark); margin: 12px 0 6px; }
.cert p { font-size: 13px; color: var(--text-sub); }

.partners { display: grid; grid-template-columns: repeat(6, 1fr); gap: 16px; }
.partner {
  height: 74px; display: grid; place-items: center; background: #fff;
  border: 1px solid var(--line); border-radius: 8px; color: var(--text-sub);
  font-weight: 700; font-size: 15px; transition: .25s;
}
.partner:hover { color: var(--brand); border-color: var(--brand); transform: translateY(-3px); }

/* 联系页 */
.contact-grid { display: grid; grid-template-columns: .9fr 1.1fr; gap: 46px; }
.info-card {
  background: var(--bg-soft); border-radius: var(--radius); padding: 26px; margin-bottom: 20px;
  border-left: 4px solid var(--brand);
}
.info-card h3 { font-size: 17px; color: var(--brand-dark); margin-bottom: 12px; }
.info-card li { display: flex; gap: 12px; margin-bottom: 12px; font-size: 14.5px; color: var(--text-sub); }
.info-card li b { color: var(--text); font-weight: 600; }
.form-card { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); padding: 34px; box-shadow: var(--shadow); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.field { margin-bottom: 18px; }
.field label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 7px; }
.field label i { color: #E0403F; font-style: normal; }
.field input, .field select, .field textarea {
  width: 100%; padding: 11px 14px; border: 1px solid var(--line); border-radius: 6px;
  font-size: 14.5px; font-family: inherit; color: var(--text); background: #fff; transition: .2s;
}
.field input:focus, .field select:focus, .field textarea:focus {
  outline: 0; border-color: var(--brand); box-shadow: 0 0 0 3px rgba(11,79,160,.1);
}
.field textarea { min-height: 118px; resize: vertical; }
.form-note { font-size: 12.5px; color: var(--text-sub); margin-top: 12px; }
.form-msg { margin-top: 14px; padding: 12px 16px; border-radius: 6px; font-size: 14px; display: none; }
.form-msg.ok { display: block; background: #E9F7EF; color: #1B7A4B; border: 1px solid #B6E3C9; }
.form-msg.err { display: block; background: #FDECEC; color: #C0392B; border: 1px solid #F5C6C6; }

/* 地图占位 */
.map-box {
  height: 260px; border-radius: var(--radius); border: 1px solid var(--line); overflow: hidden;
  background: var(--bg-soft); display: grid; place-items: center; text-align: center; color: var(--text-sub);
}

/* ===== 页脚 ===== */
.footer { background: #0A2E52; color: #B9CCE4; padding-top: 60px; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1.2fr; gap: 40px; padding-bottom: 44px; }
.footer h4 { color: #fff; font-size: 16.5px; margin-bottom: 18px; position: relative; padding-left: 13px; }
.footer h4::before { content: ""; position: absolute; left: 0; top: 6px; width: 3px; height: 15px; background: var(--accent-orange); }
.footer li { margin-bottom: 10px; font-size: 14px; }
.footer li:hover, .footer a:hover { color: #fff; }
.footer p { font-size: 14px; line-height: 1.85; }
.footer-contact li { display: flex; gap: 10px; }
.footer-contact b { color: #fff; font-weight: 600; }
.qrcode {
  width: 108px; height: 108px; background: #fff; border-radius: 8px; display: grid; place-items: center;
  color: var(--brand-dark); font-size: 12px; text-align: center; padding: 8px; line-height: 1.5;
}
.footer-bottom { border-top: 1px solid rgba(255,255,255,.12); padding: 20px 0; font-size: 13px; }
.footer-bottom .container { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

/* 返回顶部 */
#toTop {
  position: fixed; right: 22px; bottom: 26px; width: 44px; height: 44px; border: 0; border-radius: 50%;
  background: var(--brand); color: #fff; cursor: pointer; display: grid; place-items: center;
  box-shadow: 0 8px 20px rgba(11,79,160,.32); opacity: 0; pointer-events: none; transition: .25s; z-index: 90;
}
#toTop.show { opacity: 1; pointer-events: auto; }

/* 语言切换 */
.lang-switch { display: flex; align-items: center; gap: 2px; margin-left: 10px; padding-left: 16px; border-left: 1px solid var(--line); }
.lang-btn {
  background: none; border: 0; cursor: pointer; padding: 5px 9px; border-radius: 5px;
  font-size: 13.5px; font-weight: 700; letter-spacing: .5px; color: var(--text-sub); transition: .2s;
}
.lang-btn:hover { color: var(--brand); }
.lang-btn.active { color: var(--brand); background: var(--brand-light); }
.lang-sep { color: #C6D2E0; font-size: 12px; }

/* 导出/资质徽章 */
.export-badges { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; margin-top: 34px; }
.badge {
  display: inline-flex; align-items: center; gap: 8px; background: #fff; border: 1px solid var(--line);
  border-radius: 40px; padding: 8px 18px; font-size: 13.5px; color: var(--text-sub); font-weight: 600;
}
.badge svg { flex: none; }

/* 移动端菜单遮罩 */
.nav-backdrop { position: fixed; inset: 0; background: rgba(0,0,0,.4); z-index: 98; display: none; }
.nav-backdrop.show { display: block; }

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .hero-grid, .app-row, .about-intro, .contact-grid { grid-template-columns: 1fr; gap: 34px; }
  .hero .container { padding: 70px 24px; }
  .hero h1 { font-size: 34px; }
  .app-row:nth-child(even) .app-visual { order: 0; }
  .app-visual { min-height: 200px; }
  .steps, .certs { grid-template-columns: repeat(3, 1fr); }
  .values { grid-template-columns: repeat(2, 1fr); }
  .partners { grid-template-columns: repeat(3, 1fr); }
  .grid-4, .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  .topbar { display: none; }
  .nav-toggle { display: block; }
  .nav-menu {
    position: fixed; top: 0; right: 0; bottom: 0; width: 250px; background: #fff; z-index: 99;
    flex-direction: column; align-items: stretch; padding: 80px 20px 20px; gap: 2px;
    box-shadow: -8px 0 24px rgba(0,0,0,.12); transform: translateX(100%); transition: transform .28s;
  }
  .nav-menu.open { transform: translateX(0); }
  .nav-menu a { padding: 13px 10px; border-bottom: 1px solid var(--line); }
  .nav-menu a::after { display: none; }
  .nav-menu .btn { margin-top: 16px; }
  .section { padding: 54px 0; }
  .section-head h2 { font-size: 25px; }
  .stats .container { grid-template-columns: repeat(2, 1fr); }
  .stat { border-bottom: 1px solid var(--line); }
  .grid-4, .grid-3, .grid-2, .values, .certs, .steps, .partners { grid-template-columns: 1fr; }
  .partners { grid-template-columns: repeat(2, 1fr); }
  .form-row { grid-template-columns: 1fr; }
  .cta-band h2 { font-size: 22px; }
  .breadcrumb h1 { font-size: 23px; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .lang-switch { margin: 0; padding: 0; border: 0; justify-content: center; padding-top: 14px; }
}