@import url('https://fonts.googleapis.com/css2?family=Poppins:wght@300;400;600&display=swap');

    *{margin:0;padding:0;box-sizing:border-box;font-family:'Poppins',sans-serif;}
    body{background:#F5F7FA;color:#333;}

    header{
      background:#fff;
      display:flex;
      justify-content:space-between;
      align-items:center;
      padding:15px 50px;
      box-shadow:0 2px 5px rgba(0,0,0,0.1);
    }
    header img{height:50px;}
    nav a{
      margin-left:20px;
      text-decoration:none;
      color:#2F3E9E;
      font-weight:500;
    }
    nav a:hover{color:#E53935;}

    .container{padding:60px 50px;}

    h1{
      text-align:center;
      color:#2F3E9E;
      margin-bottom:40px;
    }

    .grid{
      display:grid;
      grid-template-columns:repeat(auto-fit,minmax(250px,1fr));
      gap:25px;
    }

    .card{
      background:#fff;
      padding:20px;
      border-radius:10px;
      text-align:center;
      box-shadow:0 2px 6px rgba(0,0,0,0.05);
      transition:0.3s;
    }
    .card:hover{transform:translateY(-5px);}

    .card img{
      width:100%;
      height:160px;
      object-fit:contain;
      margin-bottom:15px;
    }

    .card h3{color:#2F3E9E;margin-bottom:10px;}
    .card p{font-size:14px;margin-bottom:10px;}

    .card .button {
      background: #E53935; color: #fff; border: none;
      padding: 10px 20px; border-radius: 6px;
      cursor: pointer; transition: 0.3s;
      text-decoration: none;
    }
    .card .button:hover {background: #c62828;}

    footer{
      margin-top:50px;
      background:#2F3E9E;
      color:#fff;
      text-align:center;
      padding:30px;
    }

    /* ZALO BUTTON */
    .zalo-btn{
      position: fixed;
      bottom: 20px;
      right: 20px;
      background: #E53935;
      color: white;
      padding: 12px 18px;
      border-radius: 30px;
      text-decoration: none;
      box-shadow: 0 4px 10px rgba(0,0,0,0.2);
      z-index: 999;
      font-size:14px;
    }

    .zalo-btn:hover{
      background:#c62828;
    }
    /* THÊM VÀO CUỐI CSS */

@media(max-width:768px){

  header{
    flex-direction:column;
    padding:15px 20px;
  }

  nav{
    margin-top:10px;
  }

  nav a{
    margin:0 10px;
    font-size:13px;
  }

  .container{
    padding:40px 15px;
  }

  h1{
    font-size:24px;
  }

  .grid{
    grid-template-columns:1fr;
  }

  .card img{
    height:140px;
  }

}