.main{
	    transition-duration: 2s;

    display: flex;
    flex-direction: column; /* 设置 flex 容器为垂直方向 */
  align-items: center; /* 垂直居中 */
}
.form{
    display: flex;
   flex-direction: column; /* 设置 flex 容器为垂直方向 */
 align-items: center; /* 垂直居中 */
}
.box {
    margin: 120px auto;
    border: 1px solid #e5e5e5;
    border-radius: 4px;
    box-shadow: 0 4px 18px rgba(0,0,0,0.2);

}

.username , .yx , .password , .password2{
    height: 44px;
    width: 100%;
}