* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
  
  body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f9;
    color: #333;
    line-height: 1.6;
  }
  
  .hero {
    background: url('Image/banner.jpg') no-repeat center center/cover;
    height: 250px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    color: #fff;
    position: relative;
  }
  
  .hero::after {
    content: "";
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 100%;
    background: rgba(17, 0, 31, 0.664); /* lớp phủ mờ */
  }
  
  .hero-content {
    position: relative;
    z-index: 1;
  }
  
  .hero h1 {
    font-size: 48px;
    margin-bottom: 15px;
  }
  
  .hero p {
    font-size: 20px;
    margin-bottom: 20px;
  }
  
  nav {
    background: #196397;
  }
  
  nav ul {
    list-style: none;
    display: flex;
    justify-content: center;
  }
  
  nav ul li {
    margin: 0 15px;
  }
  
  nav ul li a {
    color: #fff;
    text-decoration: none;
    padding: 12px;
    display: block;
    transition: background 0.3s ease;
  }
  
  nav ul li a:hover {
    background: #6cb5e9;
    border-radius: 5px;
  }
  
  /* Danh sách sản phẩm */
  .product-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    margin: 30px;
    gap: 20px;
  }
  
  /* Thẻ sản phẩm */
  .product-card {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    width: 250px;
    padding: 15px;
    text-align: center;
    transition: transform 0.2s ease;
  }
  
  .product-card:hover {
    transform: scale(1.05);
  }
  
  .product-card img {
    width: 100%;
    height: 150px;
    object-fit: cover;
    border-radius: 6px;
  }
  
  /* Nút mua ngay */
  .button {
    border: none;
    padding: 10px 15px;
    margin-top: 10px;
    cursor: pointer;
    border-radius: 5px;
    font-size: 14px;
  }
  
  .button4 {
    background-color: #0077cc;
    color: white;
  }
  
  .button4:hover {
    background-color: #005fa3;
  }
  
  /* Sidebar mạng xã hội */
  .sidebar {
    position: fixed;
    top: 50%;
    right: 0;
    transform: translateY(-50%);
    background: #0077cc;
    padding: 10px;
    border-radius: 8px 0 0 8px;
  }
  
  .social-icons a {
    display: block;
    color: #fff;
    text-decoration: none;
    margin: 8px 0;
    transition: color 0.3s ease;
  }
  
  .social-icons a:hover {
    color: #ffcc00;
  }
  
  /* Footer chia cột */
  .footer {
    background: #005fa3;
    color: #fff;
    padding: 30px;
    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
  }
  
  .footer-item {
    flex: 1;
    min-width: 200px;
    margin: 10px;
  }
  
  .footer-item h3 {
    margin-bottom: 10px;
    border-bottom: 2px solid #fff;
    padding-bottom: 5px;
  }
  
  .footer-item p {
    margin-top: 5px;
  }
  
  /* Responsive cho mobile */
  @media (max-width: 768px) {
    nav ul {
      flex-direction: column;
      align-items: center;
    }
  
    .product-list {
      flex-direction: column;
      align-items: center;
    }
  
    .sidebar {
      display: none; /* Ẩn sidebar trên màn hình nhỏ */
    }
  
    .footer {
      flex-direction: column;
      text-align: center;
    }
  
    .hero h1 {
      font-size: 32px;
    }
  
    .hero p {
      font-size: 16px;
    }
   
  }