Easy way to see the Bootstrap grid?

Question

I am playing with a simple HTML page using Bootstrap and I would love to have a way to visualize the columns, as in see them \"underneath\" the actual content as a different sha

Answer 1

Updated Sherbrow's answer for Bootstrap 3:

div[class="row"] {
    outline: 1px dotted rgba(0, 0, 0, 0.25);
}

div[class^="col-"] {
    background-color: rgba(255, 0, 0, 0.2);
    outline: 1px dotted rgba(0, 0, 0, 0.5);
}