Table Border - Highlight Selected Item

HTML

<div style="padding: 10px">
<table>
    <tr>
        <td class="active">1.1</td>
        <td>1.2</td>
        <td>1.3</td>
        <td>1.4</td>
        <td>1.5</td>
    </tr>
    <tr>
        <td>2.1</td>
        <td>2.2</td>
        <td class="active">2.3</td>
        <td class="active">2.4</td>
        <td class="active">2.5</td>
    </tr>
    <tr>
        <td>3.1</td>
        <td>3.2</td>
        <td class="active">3.3</td>
        <td>3.4</td>
        <td>3.5</td>
    </tr>
    <tr>
        <td class="active">4.1</td>
        <td>4.2</td>
        <td>4.3</td>
        <td>4.4</td>
        <td>4.5</td>
    </tr>
    <tr>
        <td>5.1</td>
        <td>5.2</td>
        <td>5.3</td>
        <td class="active">5.4</td>
        <td class="active">5.5</td>
    </tr>
</table>
</div>

CSS

table {
    table-layout: fixed;
    border-spacing: 0;
    border-collapse: collapse;
}

td {
    border: 1px solid lightgrey;
    height: 60px;
    width: 60px;
    text-align: center;
    vertical-align: middle;
}

td.active {
    border: 1px solid blue;
    border-style:double;
}