.rectangle {
counter-reset: li; 
list-style: none; 
font: 14px "Trebuchet MS", "Lucida Sans";
padding: 0;
text-shadow: 0 1px 0 rgba(255,255,255,.5);
}
.rectangle a {
position: relative;
display: block;
padding: .4em .4em .4em .8em;
margin: .5em 0 .5em 2.5em;
background: #D3D4DA;
color: #444;
text-decoration: none;
transition: all .3s ease-out;
}
.rectangle a:hover {
background: #DCDDE1;
}       
.rectangle a:before {
content: counter(li);
counter-increment: li;
position: absolute;
left: -2.5em;
top: 50%;
margin-top: -1em;
background: #A4A4A4;
height: 2em;
width: 2em;
line-height: 2em;
text-align: center;
font-weight: bold;
}
.rectangle a:after {
position: absolute;
content: "";
border: .5em solid transparent;
left: -1em;
top: 50%;
margin-top: -.5em;
transition: all .3s ease-out;
}
.rectangle a:hover:after {
left: -.5em;
border-left-color: #A4A4A4;
}