[CSS] overview ДОМАШНО - 2 задача ( CSS FILE )

@charset "utf-8";
/* CSS Document */
body
{
    font-family:Helvetica, Arial, sans-serif;
}

table
{
    border-collapse:collapse;
    border-style:none;
    border-color:#CCC;
    width:825px;
    height:240px;
}

.firstCol
{
    width:30%;
}
.secondCol
{
    width:25%;
}

.fourthCol
{
    width:15%;
}

table th
{
    border-right:2px inset #FFF;
    border-top:none;
    border-bottom:none;
    line-height:38px;
    padding:5px;
    background-color:#55b806;
    text-align:left;
    font-weight: normal;
    color:#FFF;
    padding: 5px;
    line-height:30px;
}
th:nth-child(n)
{
    border-bottom:1px solid #1d381b;
}


table tr:nth-child(even)
{
    background-color:#ececd8;
}


td
{
    border-right:2px inset #FFF;

    border-top:none;
    border-bottom:none;
    line-height:38px;
    padding:5px;
}

table td:nth-child(4n)
{
    border-right:none;
}
table td:nth-child(4n+1)
{
    border-left:none;
}

table th:nth-child(4n)
{
    border-right:none;
}
table th:nth-child(4n+1)
{
    border-left:none;
}


img
{
    padding:10px;
    vertical-align:middle;
}