bootstrap-util.css

/* DEBUG */
/* Large Devices, Wide Screens */

@media only screen and (min-width : 1200px) {
    body:before {
        content: "Bootstrap: COL-LG";
        position: fixed;
        top: 0;
        left: 0;
        z-index: 99999;
        background-color: red;
        color: white;
        font-weight: bold;
    }
}

@media only screen and (min-width : 992px) and (max-width : 1199px) {
    body:before {
        content: "Bootstrap: COL-MD";
        position: fixed;
        top: 0;
        left: 0;
        z-index: 99999;
        background-color: red;
        color: white;
        font-weight: bold;
    }
}

/* Medium Devices, Desktops */
@media only screen and (min-width : 768px) and (max-width : 991px) {
    body:before {
        content: "Bootstrap: COL-SM";
        position: fixed;
        top: 0;
        left: 0;
        z-index: 99999;
        background-color: red;
        color: white;
        font-weight: bold;
    }
}

/* Small Devices, Tablets */
@media only screen and (max-width : 767px) {
    body:before {
        content: "Bootstrap: COL-XS";
        position: fixed;
        top: 0;
        left: 0;
        z-index: 99999;
        background-color: red;
        color: white;
        font-weight: bold;
    }
}