nth-child
by Petra1999
HTML
<div>
<a>1</a>
<a>2</a>
<a>3</a>
<a>4</a>
<a>5</a>
<a>6</a>
<a>7</a>
<a>8</a>
<a>9</a>
</div>
CSS
a:nth-child(2n+2){
background-color:lightblue;
}
a:nth-child(4n+1){
background-color:pink;
}
/* aaaaa */
a {
display:inline-block;
width:30px;
height:30px;
margin-right:20px;
background-color:#efefef;
}