/* --- 全局与重置样式 --- */
:root {
  --primary-color: #4f46e5; /* 充满科技感的靛蓝色 */
  --dark-color: #111827;
  --light-color: #f9fafb;
  --text-color: #374151;
  --white-color: #fff;
  --footer-bg: #1f2937;
}

html { scroll-behavior: smooth; }
* { margin: 0; padding: 0; box-sizing: border-box; }

body {
  font-family: 'PingFang SC', 'Microsoft YaHei', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.7;
  color: var(--text-color);
  background-color: var(--white-color);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container { max-width: 1140px; margin: auto; padding: 0 20px; }
section { padding: 6rem 0; }

/* --- 排版样式 --- */
h1, h2, h3 { color: var(--dark-color); line-height: 1.3; }
h1 { font-size: 3.8rem; font-weight: 800; }
h2 { font-size: 2.5rem; text-align: center; margin-bottom: 1rem; }
.section-subtitle { text-align: center; max-width: 700px; margin: 0 auto 4rem auto; font-size: 1.1rem; color: #6b7280; }

/* --- 头部导航 --- */
.main-header { background: rgba(255,255,255,0.8); backdrop-filter: blur(10px); box-shadow: 0 2px 10px rgba(0,0,0,0.05); padding: 1rem 0; position: sticky; top: 0; z-index: 1000; }
.main-header .container { display: flex; justify-content: space-between; align-items: center; }
.main-header .logo { font-size: 2rem; font-weight: 800; color: var(--primary-color); text-decoration: none; font-family: 'Microsoft YaHei', 'STXingkai', 'STKaiti', sans-serif; letter-spacing: 1px; text-shadow: 0 2px 4px rgba(0,0,0,0.15); transition: all 0.3s ease; transform: perspective(1000px) rotateX(0deg); } .main-header .logo:hover { text-shadow: 0 4px 12px rgba(79, 70, 229, 0.3); transform: perspective(1000px) rotateX(5deg); }
.main-nav ul { display: flex; list-style: none; }
.main-nav a { color: var(--dark-color); text-decoration: none; padding: 0.5rem 1rem; transition: color 0.3s; position: relative; font-weight: 500; }
.main-nav a:hover, .main-nav a.active { color: var(--primary-color); }
.main-nav a.active::after { content: ''; position: absolute; bottom: -5px; left: 1rem; right: 1rem; height: 2px; background: var(--primary-color); }

/* --- 汉堡菜单 (移动端) --- */
.hamburger { display: none; cursor: pointer; flex-direction: column; gap: 5px; }
.hamburger .line { width: 25px; height: 3px; background-color: var(--dark-color); transition: all 0.3s; }

/* --- Hero 区域 --- */
.hero {
  height: 90vh;
  min-height: 600px;
  display: flex;
  align-items: center;
  text-align: center;
  position: relative;
  color: var(--white-color);
  background-image: url('	https://static-cse.canva.cn/blob/209470/Snipaste_20200614_221327.png');/*./images/background.jpg*/
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(17, 24, 39, 0.6);
  z-index: 1;
}

.hero .container {
  position: relative;
  z-index: 2;
}

.hero h1 {
  color: var(--white-color);
}

.hero-content p { 
  font-size: 1.25rem; 
  max-width: 700px; 
  margin: 1.5rem auto 2.5rem auto; 
  color: #e5e7eb;
}

.btn { display: inline-block; background: var(--primary-color); color: var(--white-color); padding: 1rem 2.5rem; border-radius: 50px; text-decoration: none; font-size: 1rem; font-weight: 500; border: none; cursor: pointer; transition: all 0.3s; }
.btn:hover { background: #4338ca; transform: translateY(-3px); box-shadow: 0 4px 20px rgba(79, 70, 229, 0.3); }
.btn-secondary { background: transparent; color: var(--white-color); border: 1px solid rgba(255, 255, 255, 0.5); margin-left: 1rem; }
.btn-secondary:hover { background: rgba(255, 255, 255, 0.1); border-color: var(--white-color); box-shadow: none; }

/* --- 数据见证实力 --- */
.metrics { padding: 4rem 0; border-top: 1px solid #e5e7eb; border-bottom: 1px solid #e5e7eb; }
.metrics .grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; text-align: center; }
.metric-item .number { font-size: 3rem; font-weight: 700; color: var(--primary-color); }
.metric-item .label { font-size: 1rem; color: #6b7280; }

/* --- 产品选择列表 --- */
.products { background-color: var(--light-color); }
.products .grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 2.5rem; }
.product-card { background: var(--white-color); padding: 2.5rem; border-radius: 16px; border: 1px solid #e5e7eb; transition: all 0.4s cubic-bezier(0.25, 0.8, 0.25, 1); text-align: center; box-shadow: 0 4px 20px rgba(0,0,0,0.05); }
.product-card:hover { transform: translateY(-10px); box-shadow: 0 15px 30px rgba(0,0,0,0.1); }
.product-card .icon-container { display: flex; justify-content: center; align-items: center; height: 180px; margin-bottom: 1.5rem; color: var(--primary-color); }
.product-card h3 { font-size: 1.5rem; margin-bottom: 0.8rem; }
.product-card p { margin-bottom: 1.5rem; color: #6b7280; }
.btn-primary { background: var(--primary-color); color: var(--white-color); padding: 0.8rem 1.8rem; border-radius: 50px; text-decoration: none; font-size: 0.9rem; font-weight: 500; border: none; cursor: pointer; transition: all 0.3s; display: inline-block; }
.btn-primary:hover { background: #4338ca; transform: translateY(-3px); box-shadow: 0 4px 20px rgba(79, 70, 229, 0.3); }

/* --- 动画效果 --- */
.fade-in-up { opacity: 0; transform: translateY(30px); transition: opacity 0.6s ease-out, transform 0.6s ease-out; }
.fade-in-up.visible { opacity: 1; transform: translateY(0); }

/* --- 返回顶部按钮 --- */
#back-to-top { position: fixed; bottom: 20px; right: 20px; background-color: var(--primary-color); color: var(--white-color); width: 45px; height: 45px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 20px; text-decoration: none; opacity: 0; visibility: hidden; transition: all 0.3s; z-index: 999; }
#back-to-top:hover { background-color: #4338ca; }
#back-to-top.show { opacity: 1; visibility: visible; }

/* --- 页脚 --- */
.main-footer { background: var(--footer-bg); color: #9ca3af; padding-top: 5rem; }
.footer-content { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 2.5rem; padding-bottom: 4rem; }
.footer-content h4 { color: var(--white-color); margin-bottom: 1.2rem; font-weight: 500; }
.footer-content ul { list-style: none; }
.footer-content ul li { margin-bottom: 0.8rem; }
.footer-content a { color: #9ca3af; text-decoration: none; transition: color 0.3s; }
.footer-content a:hover { color: var(--white-color); }
.footer-bottom { border-top: 1px solid #374151; padding: 1.5rem 0; text-align: center; font-size: 0.9rem; }
.footer-bottom p { margin: 0; }
.footer-bottom a { color: #9ca3af; text-decoration: none; margin-left: 10px; }
.footer-bottom a:hover { text-decoration: underline; }

/* --- 响应式设计 --- */
@media (max-width: 992px) {
  .footer-content { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
  h1 { font-size: 2.8rem; }
  h2 { font-size: 2rem; }
  section { padding: 4rem 0; }
  .hero { height: auto; min-height: 70vh; }
  
  .hamburger { display: flex; }
  .hamburger.active .line:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
  .hamburger.active .line:nth-child(2) { opacity: 0; }
  .hamburger.active .line:nth-child(3) { transform: rotate(-45deg) translate(7px, -6px); }
  
  .main-nav { position: fixed; top: 70px; right: -100%; width: 100%; height: calc(100vh - 70px); background-color: rgba(255, 255, 255, 0.98); backdrop-filter: blur(5px); flex-direction: column; justify-content: center; align-items: center; transition: right 0.4s ease-in-out; }
  .main-nav.open { right: 0; }
  .main-nav ul { flex-direction: column; text-align: center; }
  .main-nav li { margin: 1.5rem 0; }
  .main-nav a { font-size: 1.5rem; }

  .metrics .grid { grid-template-columns: 1fr; gap: 3rem; }
  .hero-buttons { display: flex; flex-direction: column; gap: 1rem; align-items: center; }
  .btn-secondary { margin-left: 0; }
}