/* ==============================================
杭州锂动科技 · 官方官网定制版
蓝色科技风 | 毛玻璃 | 微动效 | 全响应式 | 商业级UI
=============================================== */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
}

::before,
::after {
  box-sizing: border-box;
}

:root {
  --primary-gradient: linear-gradient(135deg, #004182 0%, #002D59 100%);
  --secondary-gradient: linear-gradient(135deg, #4FC3F7 0%, #0288D1 100%);
  --accent-gradient: linear-gradient(135deg, #00C6FF 0%, #0072FF 100%);
  --light-gradient: linear-gradient(135deg, #F8FAFC 0%, #E2E8F0 100%);
  --dark-gradient: linear-gradient(135deg, #0A192F 0%,#112240 100%);
  
  --primary: #004182;
  --secondary: #0288D1;
  --accent: #4FC3F7;
  --light: #F8FAFC;
  --dark: #0A192F;
  --gray-100: #F7FAFC;
  --gray-200: #EDF2F7;
  --gray-300: #E2E8F0;
  --gray-400: #CBD5E0;
  --gray-500: #718096;
  --gray-600: #4A5568;
  --gray-700: #2D3748;
  --gray-800: #1A202C;
  
  --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-sm: 0 4px 6px rgba(0, 0, 0, 0.07);
  --shadow-md: 0 10px 15px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 15px 25px rgba(0, 0, 0, 0.12);
  --shadow-xl: 0 20px 40px rgba(0, 0, 0, 0.15);
  --shadow-2xl: 0 25px 50px rgba(0, 0, 0, 0.2);
  
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 24px;
  --radius-xl: 32px;
  --radius-full: 999px;
  
  --transition-fast: all 0.25s cubic-bezier(0.25, 0.8, 0.25, 1);
  --transition-normal: all 0.35s cubic-bezier(0.25, 0.8, 0.25, 1);
  --transition-slow: all 0.5s cubic-bezier(0.25, 0.8, 0.25, 1);
}

html {
  scroll-behavior: smooth;
}

body {
  background: var(--primary);
  color: white;
  line-height: 1.9;
  font-size: 16px;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  background-image: radial-gradient(circle at 10% 10%, rgba(79, 195, 247, 0.08) 0%, transparent 50%),
                    radial-gradient(circle at 90% 90%, rgba(0, 114, 255, 0.08) 0%, transparent 50%);
}

a {
  text-decoration: none;
  color: inherit;
  transition: var(--transition-normal);
}

a:hover {
  text-decoration: none;
}

ul, ol {
  list-style: none;
}

img {
  max-width: 100%;
  height: auto;
  display: block;
  object-fit: cover;
}

button, input, select, textarea {
  font-family: inherit;
  outline: none;
  border: none;
}

button {
  cursor: pointer;
}

.container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 24px;
}

.section {
  padding: 100px 0;
  position: relative;
}

.section-bg {
  background: rgba(0, 35, 70, 0.3);
  backdrop-filter: blur(10px);
}

.text-center {
  text-align: center;
}

.text-left {
  text-align: left;
}

.text-right {
  text-align: right;
}

/* =====================================
  导航栏 - 毛玻璃 + 渐变 + 滚动效果
===================================== */
.header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 9999;
  transition: var(--transition-normal);
  background: rgba(0, 40, 80, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid rgba(79, 195, 247, 0.1);
  box-shadow: var(--shadow-sm);
}

.header.active {
  background: rgba(0, 30, 60, 0.98);
  box-shadow: var(--shadow-md);
}

.nav {
  height: 90px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  position: relative;
}

.logo {
  font-size: 28px;
  font-weight: 800;
  letter-spacing: 1.5px;
  background: var(--secondary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  position: relative;
  display: flex;
  align-items: center;
  gap: 10px;
}

.logo::before {
  content: "";
  width: 0;
  height: 0;
  background: none;
  border-radius: var(--radius-sm);
}

.nav-list {
  display: flex;
  align-items: center;
  gap: 42px;
}

.nav-item {
  position: relative;
}

.nav-link {
  font-size: 15px;
  font-weight: 600;
  color: rgba(255, 255, 255, 0.9);
  padding: 8px 0;
  position: relative;
  transition: var(--transition-normal);
}

.nav-link::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 0;
  width: 0;
  height: 3px;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  transition: var(--transition-normal);
}

.nav-link:hover {
  color: var(--accent);
}

.nav-link:hover::after {
  width: 100%;
}

.nav-link.active {
  color: var(--accent);
}

.nav-link.active::after {
  width: 100%;
}

/* =====================================
  Banner 区域 - 渐变遮罩 + 高清大图
===================================== */
.banner {
  width: 100%;
  height: 800px;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  overflow: hidden;
  margin-top: 90px;
}

.banner::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 2;
}

.banner-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: 1;
}

.banner-content {
  position: relative;
  z-index: 3;
  max-width: 900px;
  padding: 0 24px;
  color: white;
  transform: translateY(-75px);
}

.banner-title {
  font-size: 58px;
  font-weight: 800;
  line-height: 1.2;
  margin-bottom: 24px;
  text-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
  animation: fadeInUp 1s ease forwards;
}

.banner-desc {
  font-size: 22px;
  margin-bottom: 40px;
  opacity: 0.95;
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.2);
  animation: fadeInUp 1s ease 0.2s forwards;
  opacity: 0;
}

.banner-buttons {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 24px;
  animation: fadeInUp 1s ease 0.4s forwards;
  opacity: 0;
}

/* =====================================
  按钮样式 - 渐变 + 悬浮动效
===================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 16px 48px;
  font-size: 16px;
  font-weight: 600;
  border-radius: var(--radius-md);
  transition: var(--transition-normal);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
  box-shadow: var(--shadow-md);
}

.btn-primary {
  background: var(--secondary-gradient);
  color: white;
}

.btn-secondary {
  background: var(--accent-gradient);
  color: white;
}

.btn-outline {
  background: transparent;
  border: 2px solid var(--accent);
  color: var(--accent);
}

.btn:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
}

.btn:active {
  transform: translateY(-2px);
}

/* =====================================
  标题样式 - 渐变文字
===================================== */
.section-title {
  text-align: center;
  margin-bottom: 70px;
  position: relative;
}

.section-title h2 {
  font-size: 44px;
  font-weight: 800;
  background: var(--secondary-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 20px;
  line-height: 1.3;
}

.section-title p {
  font-size: 18px;
  color: rgba(255, 255, 255, 0.7);
  max-width: 700px;
  margin: 0 auto;
  line-height: 1.9;
}

.section-title::after {
  content: "";
  width: 80px;
  height: 4px;
  background: var(--accent-gradient);
  border-radius: var(--radius-full);
  display: block;
  margin: 24px auto 0;
}

/* =====================================
  卡片组件 - 高级悬浮 + 阴影
===================================== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 36px;
}

.card {
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  transition: var(--transition-slow);
  position: relative;
  border: 1px solid rgba(79, 195, 247, 0.1);
  backdrop-filter: blur(10px);
}

.card:hover {
  transform: translateY(-12px);
  box-shadow: var(--shadow-2xl);
  border-color: rgba(79, 195, 247, 0.3);
}

.card-img {
  width: 100%;
  height: 280px;
  object-fit: cover;
  transition: var(--transition-slow);
}

.card:hover .card-img {
  transform: scale(1.08);
}

.card-body {
  padding: 36px;
  padding-top: 60px;
  flex: 1;
}

.card h3 {
  font-size: 24px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 16px;
  line-height: 1.4;
}

.card p {
  font-size: 15px;
  color: rgba(255, 255, 255, 0.8);
  line-height: 1.9;
}

.card-tag {
  position: absolute;
  top: 20px;
  left: 20px;
  padding: 6px 16px;
  background: var(--accent-gradient);
  color: white;
  font-size: 13px;
  font-weight: 600;
  border-radius: var(--radius-full);
  z-index: 2;
}

/* =====================================
  内容面板 - 高级信息展示
===================================== */
.info-panel {
  background: rgba(255, 255, 255, 0.05);
  border-radius: var(--radius-lg);
  padding: 48px;
  margin-bottom: 36px;
  box-shadow: var(--shadow-md);
  transition: var(--transition-normal);
  border: 1px solid rgba(79, 195, 247, 0.1);
  backdrop-filter: blur(10px);
}

.info-panel:hover {
  box-shadow: var(--shadow-xl);
  border-color: rgba(79, 195, 247, 0.3);
}

.info-panel h3 {
  font-size: 28px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 24px;
  position: relative;
  padding-left: 20px;
}

.info-panel h3::before {
  content: "";
  position: absolute;
  left: 0;
  top: 8px;
  width: 6px;
  height: 28px;
  background: var(--accent-gradient);
  border-radius: var(--radius-sm);
}

.info-panel p {
  font-size: 16px;
  color: rgba(255, 255, 255, 0.85);
  line-height: 2;
  margin-bottom: 16px;
}

.info-panel ul {
  padding-left: 24px;
  margin: 16px 0;
}

.info-panel li {
  font-size: 16px;
  color: rgba(255, 255, 255, 0.85);
  margin-bottom: 12px;
  position: relative;
  padding-left: 20px;
}

.info-panel li::before {
  content: "•";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: bold;
}

/* =====================================
  产品系列卡片
===================================== */
.product-card {
  background: rgba(0, 50, 100, 0.4);
  border-radius: var(--radius-lg);
  padding: 40px;
  margin-bottom: 30px;
  box-shadow: var(--shadow-md);
  transition: var(--transition-normal);
  border: 1px solid rgba(79, 195, 247, 0.2);
}

.product-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-xl);
  border-color: rgba(79, 195, 247, 0.4);
}

.product-card h3 {
  font-size: 26px;
  font-weight: 700;
  color: var(--accent);
  margin-bottom: 20px;
}

.product-card h4 {
  font-size: 20px;
  color: var(--accent);
  margin: 15px 0 10px;
}

.product-card p {
  color: rgba(255, 255, 255, 0.85);
  line-height: 1.8;
  margin-bottom: 12px;
}

.product-model {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
}

.product-model span {
  background: rgba(79, 195, 247, 0.1);
  padding: 8px 16px;
  border-radius: 8px;
  font-size: 14px;
  color: var(--accent);
  border: 1px solid rgba(79, 195, 247, 0.3);
}

/* =====================================
  统计数字样式
===================================== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 30px;
  margin: 60px 0;
}

.stat-item {
  background: rgba(255, 255, 255, 0.05);
  padding: 40px 24px;
  border-radius: var(--radius-lg);
  text-align: center;
  box-shadow: var(--shadow-md);
  transition: var(--transition-normal);
  border: 1px solid rgba(79, 195, 247, 0.1);
}

.stat-item:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-xl);
  border-color: rgba(79, 195, 247, 0.3);
}

.stat-number {
  font-size: 48px;
  font-weight: 800;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  margin-bottom: 12px;
}

.stat-label {
  font-size: 16px;
  color: rgba(255, 255, 255, 0.7);
  font-weight: 500;
}

/* =====================================
  联系表单
===================================== */
.contact-form {
  background: rgba(255, 255, 255, 0.05);
  padding: 50px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  max-width: 800px;
  margin: 0 auto;
  border: 1px solid rgba(79, 195, 247, 0.1);
}

.form-group {
  margin-bottom: 28px;
}

.form-label {
  display: block;
  font-size: 16px;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 12px;
}

.form-control {
  width: 100%;
  padding: 18px 24px;
  font-size: 16px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(79, 195, 247, 0.2);
  border-radius: var(--radius-md);
  transition: var(--transition-normal);
  color: white;
}

.form-control::placeholder {
  color: rgba(255, 255, 255, 0.5);
}

.form-control:focus {
  border-color: var(--accent);
  background: rgba(255, 255, 255, 0.1);
  box-shadow: 0 0 0 4px rgba(79, 195, 247, 0.1);
}

textarea.form-control {
  min-height: 160px;
  resize: vertical;
}

/* =====================================
  底部区域 - 渐变背景
===================================== */
.footer {
  background: var(--primary-gradient);
  color: white;
  padding: 80px 0 30px;
  position: relative;
  overflow: hidden;
  border-top: 1px solid rgba(79, 195, 247, 0.1);
}

.footer::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1440 320"><path fill="rgba(255,255,255,0.05)" fill-opacity="1" d="M0,192L48,176C96,160,192,128,288,128C384,128,480,160,576,176C672,192,768,192,864,176C960,160,1056,128,1152,117.3C1248,107,1344,117,1392,122.7L1440,128L1440,320L1392,320C1344,320,1248,320,1152,320C1056,320,960,320,864,320C768,320,672,320,576,320C480,320,384,320,288,320C192,320,96,320,48,320L0,320Z"></path></svg>');
  background-size: cover;
  background-position: center;
  opacity: 0.1;
  z-index: 0;
}

.footer-content {
  position: relative;
  z-index: 2;
  text-align: center;
}

.footer-logo {
  font-size: 32px;
  font-weight: 800;
  margin-bottom: 24px;
  color: var(--accent);
}

.footer-desc {
  font-size: 16px;
  opacity: 0.85;
  max-width: 700px;
  margin: 0 auto 40px;
  line-height: 1.9;
}

.footer-copyright {
  padding-top: 30px;
  margin-top: 50px;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  text-align: center;
  font-size: 15px;
  opacity: 0.7;
}

/* =====================================
  动画关键帧
===================================== */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* =====================================
  响应式布局 - 全设备适配
===================================== */
@media (max-width: 1200px) {
  .card-grid {
    gap: 24px;
  }
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 992px) {
  .banner-title {
    font-size: 46px;
  }
  .section-title h2 {
    font-size: 38px;
  }
  .card-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .nav-list {
    gap: 24px;
  }
}

@media (max-width: 768px) {
  .banner {
    height: 600px;
  }
  .banner-title {
    font-size: 36px;
  }
  .banner-desc {
    font-size: 18px;
  }
  .section {
    padding: 70px 0;
  }
  .card-grid {
    grid-template-columns: 1fr;
  }
  .stats-grid {
    grid-template-columns: 1fr;
  }
  .nav {
    height: 80px;
  }
  .logo {
    font-size: 22px;
  }
  .nav-list {
    display: none;
  }
  .info-panel,
  .product-card,
  .contact-form {
    padding: 30px 24px;
  }
}

@media (max-width: 480px) {
  .banner-buttons {
    flex-direction: column;
    gap: 16px;
  }
  .btn {
    width: 100%;
  }
  .banner-title {
    font-size: 30px;
  }
  .section-title h2 {
    font-size: 32px;
  }
}