html {
    height: 100%;
    overflow: hidden;
  }
  body {
    background: url("https://images.pexels.com/photos/1323550/pexels-photo-1323550.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=2") no-repeat center center fixed;
    color: #fff;
    font-family: sans-serif;
    text-align: center;
    min-height: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
  }

  h1 {
    font-size: 4rem;
    text-shadow: 1px 1px 5px #000;  
    margin: 0;
  }
  p {
    font-size: 1.2rem;  
    text-shadow: 1px 1px 2px #000;
  }
  a {
    color: #fff;
  }

  #countdown {
    max-width: 600px;
  }
  #countdown ul {
    margin: 5% 0 0 0;
    padding: 0;
    display: flex;
    gap: 5%;
  }
  #countdown ul li {
    flex: 25%;
    padding: 5%;
    margin: 0;
    list-style: none;
    background: #001f2f;
    border-radius: 5px;
  }
  #countdown ul li span {
    display: block;
    font-size: 3rem;
  }