*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;
}
body,html{
    width: 100%;
    height: 100vh;
}
li{
    list-style: none;
}
/** 重置文本格式元素 **/
a{
    text-decoration: none;
}
a:hover{
    text-decoration: underline;
}