* {
    margin: 0;
    padding: 0;
    /* c3盒子模型 */
    box-sizing: border-box;}

body {
    background-color: rgb(245,
            245,
            245);
            font-family: 'Microsoft YaHei', sans-serif;
                line-height: 1.5;
                font-size: 1vw;
                overflow-y: auto;}

/* em和i斜体的文字不倾斜 */
em,
i {
    font-style: normal;}

li {
    list-style: none;}

img {
    border: 0;
    vertical-align: middle;}

button {
    cursor: pointer;}

a {
    color: #666;
    text-decoration: none;}

a:hover {
    color: red;}

button,
input {
    /* 去除默认的黑色边框 */
    border: 0;
    outline: none;}