body {
    margin: 0;
    padding: 0;
  }
  
  .container {
    border: 2px solid blue;
    width: 90%;
    margin: 20px auto;
    padding: 10px;
  }
  
  .banner {
    background-color: deeppink;
    color: black;
    text-align: center;
    padding: 20px;
    font-weight: bold;
    font-size: 20px;
    transition: all 0.5s ease;
  }
  
  .content {
    display: flex;
    justify-content: space-around;
    align-items: center;
    margin-top: 20px;
    flex-wrap: wrap;
  }
  
  /* Khung 1 */
  .item {
    position: relative;
    border: 3px solid red;
    width: 150px;
    height: 150px;
    overflow: hidden;
  }
  
  .item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
  }
  
  .text {
    position: absolute;
    top: 5px;
    left: 10px;
    color: yellow;
    font-size: 24px;
    font-weight: bold;
  }
  
  /* Box 2 & 3 */
  .box {
    width: 150px;
    height: 150px;
    background-color: cyan;
    text-align: center;
    line-height: 150px;
    color: yellow;
    font-size: 32px;
    font-weight: bold;
    margin: 10px;
  }
  
  .box2 {
    border: 3px dashed blue;
    background-color: cyan;
    color: yellow;
    border-top-right-radius: 20px;
    border-bottom-left-radius: 20px;
  }
  
  
  .box3 {
    border: 3px dotted magenta;
    background-color: cyan;
    color: yellow;
    border-top-left-radius: 20px;
    border-bottom-right-radius: 20px;
  }
  
  /* Box 4: Xoay liên tục */
  .rotate {
    width: 150px;
    height: 150px;
    background-color: darkcyan;
    color: yellow;
    text-align: center;
    line-height: 150px;
    border: 2px solid olive;
    font-size: 20px;
    font-family: serif;
    animation: spin 4s linear infinite;
  }
  
  @keyframes spin {
    0%   { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
  }