.wrapper
{
    width: 960px;
    margin: auto;
    background-color: aqua;
    border-radius: 15px;
}

.main
{
    float: left;
    width: 640px;
}

.intro
{
    border-radius: 15px;
    background-color: yellowgreen;
    box-shadow: 5px 5px;
    width: 150px;
}

aside
{
    float: right;
    width: 320px;
}

footer
{
    clear: both;
}

ol
{
    list-style: decimal-leading-zero;
}

a:hover
{
    color: orange;
}