* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
      background: linear-gradient(135deg, #0056a7, #165fa3, #477aaa);
    }

    header{
	 display: flex;
      justify-content: center;
      align-items: center;
      flex-direction: column;
      height: 100vh;
      color: #eee;
      text-align: center;
      animation: finsDon 2s ease-in-out;
    }
    @keyframes finsDon {
      from{ /*注意别写错啦*/
        opacity: 0;
      }
      to{
        opacity: 1;
      }
    }