html简单的菜单

/* navigation start */
.nav {
max-width: ;
height: ;
display: -webkit-box;
display: -ms-flexbox;
display: flex;
-webkit-box-orient: horizontal;
-webkit-box-direction: normal;
-ms-flex-flow: row wrap;
flex-flow: row wrap;
-webkit-box-align: center;
-ms-flex-align: center;
align-items: center;
margin: auto;
}