/* ===== 基础变量 ===== */
:root {
  --brand: #C62828;
  --brand-dark: #9E1B1B;
  --brand-light: #FFEBEE;
  --text: #1f2937;
  --text-secondary: #6b7280;
  --bg: #ffffff;
  --bg-alt: #f8f9fa;
  --bg-dark: #1a1a1a;
  --border: #e5e7eb;
  --radius: 12px;
  --radius-sm: 8px;
  --shadow: 0 4px 20px rgba(0,0,0,0.06);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.12);
  --max-width: 1200px;
  --header-height: 72px;
  --transition: 0.25s ease;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
  color: var(--text);
  line-height: 1.7;
  background: var(--bg);
}
img { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }

.container {
  width: 92%;
  max-width: var(--max-width);
  margin: 0 auto;
}

.section {
  padding: 90px 0;
}
.section-light { background: var(--bg); }
.section-alt { background: var(--bg-alt); }
.section-dark {
  background: var(--bg-dark);
  color: #fff;
}

.section-head {
  text-align: center;
  margin-bottom: 56px;
}
.section-en {
  font-size: 13px;
  letter-spacing: 2px;
  color: var(--brand);
  font-weight: 600;
  margin-bottom: 8px;
}
.section-title {
  font-size: 34px;
  font-weight: 700;
  margin-bottom: 12px;
}
.section-title.light { color: #fff; }
.section-subtitle {
  color: var(--text-secondary);
  font-size: 16px;
  max-width: 600px;
  margin: 0 auto;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 15px;
  transition: var(--transition);
  cursor: pointer;
  border: none;
}
.btn-primary {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 6px 18px rgba(198,40,40,0.25);
}
.btn-primary:hover { background: var(--brand-dark); transform: translateY(-2px); }
.btn-outline {
  background: transparent;
  color: #fff;
  border: 1.5px solid rgba(255,255,255,0.7);
}
.btn-outline:hover { background: rgba(255,255,255,0.1); }
.btn-block { width: 100%; }
.mt-2 { margin-top: 24px; }

/* ===== 导航 ===== */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--header-height);
  background: rgba(255,255,255,0.96);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 rgba(0,0,0,0.05);
  z-index: 1000;
  transition: var(--transition);
}
.nav-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
}
.brand-icon {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  object-fit: cover;
}
.main-nav {
  display: flex;
  align-items: center;
  gap: 6px;
}
.nav-link {
  padding: 8px 14px;
  font-size: 14px;
  color: var(--text-secondary);
  border-radius: 50px;
  transition: var(--transition);
}
.nav-link:hover, .nav-link.active {
  color: var(--brand);
  background: var(--brand-light);
}
.nav-link.cta-link {
  background: var(--brand);
  color: #fff;
  margin-left: 8px;
}
.nav-link.cta-link:hover { background: var(--brand-dark); }
.menu-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}
.menu-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text);
  transition: var(--transition);
}

/* ===== HERO ===== */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  color: #fff;
  overflow: hidden;
  padding-top: var(--header-height);
}
.hero-bg {
  position: absolute;
  inset: 0;
  z-index: 0;
}
.hero-bg img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  filter: brightness(0.75);
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(0,0,0,0.55) 0%, rgba(0,0,0,0.25) 100%);
  z-index: 1;
}
.hero-content {
  position: relative;
  z-index: 2;
  max-width: 880px;
}
.hero-label {
  font-size: 13px;
  letter-spacing: 3px;
  opacity: 0.85;
  margin-bottom: 18px;
}
.hero-title {
  font-size: 56px;
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 24px;
}
.hero-subtitle {
  font-size: 18px;
  opacity: 0.92;
  max-width: 720px;
  margin: 0 auto 36px;
  line-height: 1.8;
}
.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
}
.scroll-down {
  position: absolute;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 2;
  width: 32px;
  height: 52px;
  border: 2px solid rgba(255,255,255,0.6);
  border-radius: 16px;
}
.scroll-down span {
  display: block;
  width: 6px;
  height: 10px;
  background: #fff;
  border-radius: 3px;
  margin: 10px auto 0;
  animation: scrollBounce 1.8s infinite;
}
@keyframes scrollBounce {
  0%, 100% { transform: translateY(0); opacity: 1; }
  50% { transform: translateY(10px); opacity: 0.5; }
}

/* ===== 数据条 ===== */
.stats {
  background: var(--brand);
  color: #fff;
  padding: 56px 0;
}
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
  text-align: center;
}
.stat-number {
  font-size: 42px;
  font-weight: 800;
  line-height: 1;
  margin-bottom: 10px;
}
.stat-label {
  font-size: 15px;
  opacity: 0.9;
}

/* ===== 关于 ===== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: center;
}
.about-media {
  position: relative;
}
.about-image-main {
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.about-image-main img { width: 100%; height: 380px; object-fit: cover; }
.about-image-sub {
  position: absolute;
  right: -24px;
  bottom: -32px;
  width: 55%;
  border-radius: var(--radius);
  overflow: hidden;
  border: 6px solid #fff;
  box-shadow: var(--shadow);
}
.about-image-sub img { width: 100%; height: 180px; object-fit: cover; }
.about-lead {
  font-size: 24px;
  font-weight: 700;
  line-height: 1.5;
  margin-bottom: 24px;
  color: var(--text);
}
.about-body p {
  color: var(--text-secondary);
  margin-bottom: 16px;
}
.about-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 24px 0;
}
.badge {
  display: inline-block;
  padding: 6px 14px;
  background: var(--brand-light);
  color: var(--brand);
  font-size: 13px;
  font-weight: 600;
  border-radius: 50px;
}

/* ===== 五大体系 ===== */
.systems-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 20px;
}
.system-card {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px 22px;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.system-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.system-icon {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--brand);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  margin-bottom: 18px;
}
.system-card h3 {
  font-size: 18px;
  margin-bottom: 6px;
}
.system-en {
  font-size: 11px;
  letter-spacing: 1px;
  color: var(--brand);
  font-weight: 600;
  margin-bottom: 12px;
}
.system-card p:last-child {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== 高配证据 ===== */
.spec-group { margin-bottom: 56px; }
.spec-group:last-child { margin-bottom: 0; }
.spec-group-title {
  font-size: 22px;
  margin-bottom: 24px;
  padding-left: 14px;
  border-left: 4px solid var(--brand);
}
.material-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.material-card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  transition: var(--transition);
}
.material-card:hover { border-color: var(--brand); box-shadow: var(--shadow); }
.material-name {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 6px;
}
.material-value {
  font-size: 18px;
  font-weight: 700;
  color: var(--brand);
  margin-bottom: 8px;
}
.material-note { font-size: 14px; color: var(--text-secondary); }

.craft-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 20px;
}
.craft-item {
  background: #fff;
  border-radius: var(--radius);
  padding: 26px;
  box-shadow: var(--shadow);
}
.craft-num {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--brand-light);
  color: var(--brand);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  margin-bottom: 16px;
}
.craft-item h4 { font-size: 17px; margin-bottom: 10px; }
.craft-item p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

.table-wrap { overflow-x: auto; }
.spec-table {
  width: 100%;
  border-collapse: collapse;
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.spec-table th, .spec-table td {
  padding: 16px 20px;
  text-align: left;
  border-bottom: 1px solid var(--border);
}
.spec-table th {
  background: var(--bg-dark);
  color: #fff;
  font-weight: 600;
}
.spec-table tr:last-child td { border-bottom: none; }
.spec-table td:first-child { font-weight: 600; }
.spec-table td:nth-child(2) { color: var(--brand); font-weight: 700; }

/* ===== 产品中心 ===== */
.product-category { margin-bottom: 64px; }
.product-category:last-child { margin-bottom: 0; }
.category-head {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 28px;
  flex-wrap: wrap;
  gap: 12px;
}
.category-title {
  font-size: 24px;
  font-weight: 700;
}
.category-guide {
  font-size: 14px;
  color: var(--text-secondary);
  max-width: 520px;
}
/* ===== 产品中心：Tab + 列表 + 左文右图 ===== */
.product-tabs {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-bottom: 36px;
  flex-wrap: wrap;
}
.product-tabs .ptab {
  border: 1.5px solid var(--line);
  background: #fff;
  color: var(--text-secondary);
  padding: 11px 30px;
  border-radius: 999px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}
.product-tabs .ptab:hover { border-color: var(--brand); color: var(--brand); }
.product-tabs .ptab.active {
  background: var(--brand);
  border-color: var(--brand);
  color: #fff;
  box-shadow: 0 8px 20px rgba(198, 40, 40, .25);
}

.product-main {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 28px;
  align-items: start;
}

/* 左侧产品列表 */
.product-list { display: flex; flex-direction: column; gap: 10px; }
.pl-item {
  text-align: left;
  background: #fff;
  border: 1.5px solid var(--line);
  border-left: 4px solid transparent;
  border-radius: 12px;
  padding: 14px 16px;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.pl-item:hover { border-color: var(--brand); transform: translateX(2px); }
.pl-item.active {
  border-color: var(--brand);
  border-left-color: var(--brand);
  background: #fff5f5;
  box-shadow: var(--shadow);
}
.pl-name { font-size: 15px; font-weight: 600; color: var(--text); }
.pl-en { font-size: 11px; color: var(--text-secondary); letter-spacing: .3px; }

/* 右侧详情：左文右图 */
.product-detail {
  background: #fff;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 540px;
}
.product-detail.fade-in { animation: pdFade .4s ease; }
@keyframes pdFade {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}
.pd-info { padding: 32px 34px; overflow-y: auto; }
.pd-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 12px; margin-bottom: 8px; }
.pd-name { font-size: 22px; margin: 0; }
.pd-en { font-size: 12px; color: var(--text-secondary); margin: 2px 0 0; letter-spacing: .3px; }
.pd-tag {
  flex-shrink: 0;
  font-size: 12px;
  font-weight: 600;
  color: var(--brand);
  background: #fff5f5;
  border: 1px solid #ffd9d9;
  padding: 5px 10px;
  border-radius: 999px;
  white-space: nowrap;
}
.pd-desc { font-size: 14px; color: var(--text-secondary); line-height: 1.8; margin: 10px 0 18px; }
.pd-sub {
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  margin: 18px 0 10px;
  padding-left: 10px;
  border-left: 3px solid var(--brand);
}
.pd-config { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 16px; }
.cfg-item { display: flex; flex-direction: column; gap: 2px; padding: 8px 0; border-bottom: 1px dashed var(--line); }
.cfg-k { font-size: 12px; color: var(--text-secondary); }
.cfg-v { font-size: 14px; font-weight: 600; color: var(--text); }
.pd-colors { display: flex; align-items: center; gap: 12px; }
.color-dots { display: inline-flex; gap: 8px; }
.color-dot { width: 22px; height: 22px; border-radius: 50%; border: 2px solid #fff; box-shadow: 0 0 0 1px var(--line); }
.color-names { font-size: 13px; color: var(--text-secondary); }
.pd-perf { display: flex; flex-direction: column; gap: 1px; background: #f7f8fa; border-radius: 10px; overflow: hidden; }
.perf-row { display: flex; justify-content: space-between; padding: 9px 14px; font-size: 13px; }
.perf-row:nth-child(odd) { background: #fff; }
.perf-k { color: var(--text-secondary); }
.perf-v { font-weight: 700; color: var(--brand); }

.pd-image {
  background: linear-gradient(135deg, #f3f4f6, #e9ecef);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 28px;
}
.pd-image img { max-width: 100%; max-height: 520px; width: auto; height: auto; object-fit: contain; filter: drop-shadow(0 12px 24px rgba(0,0,0,.12)); }
.pd-cap { margin-top: 14px; font-size: 12px; color: var(--text-secondary); letter-spacing: .5px; }

/* 产品结构图 / 效果示意 切换 */
.pd-view-toggle {
  display: inline-flex;
  background: #fff;
  border: 1.5px solid var(--line);
  border-radius: 999px;
  padding: 4px;
  margin-bottom: 18px;
  box-shadow: 0 2px 8px rgba(0,0,0,.05);
}
.pdv-btn {
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 600;
  padding: 7px 16px;
  border-radius: 999px;
  cursor: pointer;
  transition: var(--transition);
}
.pdv-btn:hover { color: var(--brand); }
.pdv-btn.active {
  background: var(--brand);
  color: #fff;
  box-shadow: 0 4px 12px rgba(198, 40, 40, .25);
}

.sunroom-card {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 0;
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
}
.sunroom-image { height: 100%; min-height: 360px; display: flex; align-items: center; justify-content: center; background: #f3f4f6; }
.sunroom-image img { max-width: 100%; max-height: 100%; width: auto; height: auto; object-fit: contain; }
.sunroom-body { padding: 40px; display: flex; flex-direction: column; justify-content: center; }
.sunroom-body h4 { font-size: 24px; margin-bottom: 8px; }
.sunroom-body > p:last-of-type {
  color: var(--text-secondary);
  margin: 16px 0;
  line-height: 1.8;
}
.sunroom-list {
  list-style: none;
  margin-top: 8px;
}
.sunroom-list li {
  padding: 8px 0 8px 24px;
  position: relative;
  font-size: 14px;
}
.sunroom-list li::before {
  content: "";
  position: absolute;
  left: 0; top: 15px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--brand);
}

/* ===== 应用场景 ===== */
.scenario-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.scenario-card {
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.scenario-card:hover { transform: translateY(-5px); }
.scenario-image { height: 200px; }
.scenario-image img { width: 100%; height: 100%; object-fit: cover; }
.scenario-body { padding: 22px; }
.scenario-body h4 { font-size: 18px; margin-bottom: 12px; }
.scenario-pain {
  font-size: 13px;
  color: var(--brand);
  font-weight: 600;
  margin-bottom: 8px;
}
.scenario-solution {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== 服务流程 ===== */
.process-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 16px;
  position: relative;
}
.process-grid::before {
  content: "";
  position: absolute;
  top: 34px;
  left: 10%;
  right: 10%;
  height: 2px;
  background: linear-gradient(90deg, var(--brand) 0%, rgba(198,40,40,0.2) 100%);
  z-index: 0;
}
.process-step {
  background: #fff;
  border-radius: var(--radius);
  padding: 28px 20px;
  box-shadow: var(--shadow);
  text-align: center;
  position: relative;
  z-index: 1;
}
.process-num {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--brand);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-size: 16px;
  margin: 0 auto 18px;
}
.process-step h4 { font-size: 17px; margin-bottom: 10px; }
.process-step p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* ===== 工程案例 ===== */
.case-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}
.case-card {
  background: #fff;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  transition: var(--transition);
}
.case-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }
.case-image { height: 220px; }
.case-image img { width: 100%; height: 100%; object-fit: cover; }
.case-body { padding: 22px; }
.case-body h4 { font-size: 18px; margin-bottom: 6px; }
.case-meta {
  font-size: 12px;
  color: var(--brand);
  font-weight: 600;
  margin-bottom: 10px;
}
.case-body p:last-child {
  font-size: 14px;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ===== FAQ ===== */
.faq-list {
  max-width: 800px;
  margin: 0 auto;
}
.faq-item {
  background: #fff;
  border-radius: var(--radius);
  margin-bottom: 14px;
  box-shadow: var(--shadow);
  overflow: hidden;
}
.faq-item summary {
  padding: 20px 24px;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-size: 22px;
  color: var(--brand);
  font-weight: 400;
}
.faq-item[open] summary::after { content: "−"; }
.faq-item p {
  padding: 0 24px 20px;
  color: var(--text-secondary);
  line-height: 1.8;
  font-size: 15px;
}

/* ===== 新闻 ===== */
.news-list {
  max-width: 900px;
  margin: 0 auto;
}
.news-item {
  display: flex;
  gap: 24px;
  padding: 28px 0;
  border-bottom: 1px solid var(--border);
}
.news-item:last-child { border-bottom: none; }
.news-date {
  flex-shrink: 0;
  width: 72px;
  text-align: center;
}
.news-date .day {
  display: block;
  font-size: 32px;
  font-weight: 800;
  color: var(--brand);
  line-height: 1;
}
.news-date .month {
  font-size: 13px;
  color: var(--text-secondary);
}
.news-body h4 { font-size: 18px; margin-bottom: 8px; transition: color 0.2s; }
.news-item:hover .news-body h4 { color: var(--brand); }
.news-body p { font-size: 14px; color: var(--text-secondary); line-height: 1.7; }

/* ===== 联系我们 ===== */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 56px;
  align-items: start;
}
.contact-info .section-en { color: var(--brand); }
.contact-lead {
  color: rgba(255,255,255,0.75);
  margin: 16px 0 32px;
  font-size: 16px;
}
.contact-list { list-style: none; margin-bottom: 32px; }
.contact-list li {
  display: flex;
  flex-direction: column;
  padding: 14px 0;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.contact-label { font-size: 13px; color: rgba(255,255,255,0.55); margin-bottom: 4px; }
.contact-value { font-size: 16px; color: #fff; }
.contact-brand {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-top: 24px;
}
.contact-logo {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  object-fit: cover;
}
.contact-form-wrap {
  background: #fff;
  border-radius: var(--radius);
  padding: 36px;
  color: var(--text);
}
.contact-form-wrap h3 { font-size: 22px; margin-bottom: 24px; }
.contact-form input,
.contact-form select,
.contact-form textarea {
  width: 100%;
  padding: 14px 16px;
  margin-bottom: 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  font-size: 15px;
  font-family: inherit;
  transition: var(--transition);
}
.contact-form input:focus,
.contact-form select:focus,
.contact-form textarea:focus {
  outline: none;
  border-color: var(--brand);
  box-shadow: 0 0 0 3px var(--brand-light);
}
.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}
.form-note {
  font-size: 12px;
  color: var(--text-secondary);
  margin-top: 12px;
  text-align: center;
}

/* ===== 页脚 ===== */
.site-footer {
  background: #111;
  color: rgba(255,255,255,0.7);
  padding: 64px 0 24px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr 1.4fr;
  gap: 40px;
  margin-bottom: 48px;
}
.footer-logo {
  height: 42px;
  width: auto;
  margin-bottom: 16px;
  filter: brightness(1.1);
}
.footer-brand p { font-size: 14px; line-height: 1.8; }
.footer-links h4,
.footer-contact h4 {
  color: #fff;
  font-size: 15px;
  margin-bottom: 18px;
}
.footer-links a {
  display: block;
  font-size: 14px;
  margin-bottom: 10px;
  transition: color 0.2s;
}
.footer-links a:hover { color: var(--brand); }
.footer-contact p { font-size: 14px; margin-bottom: 10px; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 24px;
  text-align: center;
  font-size: 13px;
  color: rgba(255,255,255,0.5);
}
.footer-bottom p { margin-bottom: 6px; }
.footer-bottom .footer-beian a { color: rgba(255,255,255,0.7); text-decoration: none; transition: var(--transition); }
.footer-bottom .footer-beian a:hover { color: #fff; }
.footer-bottom .dot-sep { margin: 0 8px; color: rgba(255,255,255,0.4); }

/* ===== 返回顶部 ===== */
.back-to-top {
  position: fixed;
  right: 24px;
  bottom: 24px;
  width: 44px;
  height: 44px;
  background: var(--brand);
  color: #fff;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  visibility: hidden;
  transition: var(--transition);
  box-shadow: 0 4px 14px rgba(198,40,40,0.35);
  z-index: 999;
}
.back-to-top.visible { opacity: 1; visibility: visible; }
.back-to-top svg { width: 20px; height: 20px; }

/* ===== 滚动动画 ===== */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.active {
  opacity: 1;
  transform: translateY(0);
}

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
  .systems-grid { grid-template-columns: repeat(3, 1fr); }
  .process-grid { grid-template-columns: repeat(3, 1fr); }
  .process-grid::before { display: none; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 768px) {
  :root { --header-height: 64px; }
  .section { padding: 64px 0; }
  .section-title { font-size: 26px; }
  .hero-title { font-size: 34px; }
  .hero-subtitle { font-size: 15px; }
  .hero-actions { flex-direction: column; align-items: center; }
  .hide-mobile { display: none; }
  .menu-toggle { display: flex; }
  .main-nav {
    position: fixed;
    top: var(--header-height);
    left: 0; right: 0;
    background: #fff;
    flex-direction: column;
    align-items: stretch;
    padding: 16px 20px;
    gap: 4px;
    box-shadow: var(--shadow);
    transform: translateY(-120%);
    opacity: 0;
    transition: var(--transition);
    pointer-events: none;
  }
  .main-nav.open {
    transform: translateY(0);
    opacity: 1;
    pointer-events: auto;
  }
  .nav-link { padding: 12px 16px; }
  .nav-link.cta-link { margin-left: 0; text-align: center; }
  .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 24px 12px; }
  .stat-number { font-size: 32px; }
  .about-grid { grid-template-columns: 1fr; gap: 36px; }
  .about-image-sub { position: static; width: 70%; margin: -40px auto 0; }
  .systems-grid,
  .material-grid,
  .craft-grid,
  .product-main,
  .product-detail,
  .scenario-grid,
  .case-grid { grid-template-columns: 1fr; }
  .process-grid { grid-template-columns: 1fr; }
  .category-head { flex-direction: column; align-items: flex-start; }
  .product-list { flex-direction: row; overflow-x: auto; padding-bottom: 6px; gap: 8px; }
  .pl-item { flex: 0 0 auto; min-width: 150px; }
  .pd-info { padding: 24px; }
  .pd-image { min-height: 280px; padding: 20px; }
  .pd-image img { max-height: 360px; }
  .pd-view-toggle { margin-bottom: 12px; }
  .contact-grid { grid-template-columns: 1fr; gap: 40px; }
  .form-row { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; gap: 32px; }
  .news-item { flex-direction: column; gap: 12px; }
}

@media (max-width: 480px) {
  .hero-title { font-size: 28px; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .brand-text { font-size: 15px; }
  .brand-icon { width: 36px; height: 36px; }
}