a {
color: blue;
transition: color 1s;
}
a:hover {
color: red;
}
.bar {
width: 200px;
height: 20px;
border: 1px solid #333;
}
.bar div {
width: 0%;
height: 20px;
background: lime;
transition: width 3s;
}
.bar:hover div {
width: 100%;
}