responsive.css

/* Responsive web design introduction */

.header {
    background-color: #0099cc;
    color: #ffffff;
    text-align: center;
    font-size: 24px;
    padding: 15px;
    border:1px solid black;
}

.footer {
    background-color: #0099cc;
    color: #ffffff;
    text-align: center;
    font-size: 24px;
    padding: 15px;
    border:1px solid black;
}

/* Sudo Element to clear float after row class */

.row::after {
    content: "";
    clear: both;
    display: table;
}

/* Selects all elements which have class name starting with col- */

[class*="col-"] {
    float: left;
    padding: 10px;
    background-color: #07cc00;
    margin:5px;
    height:150px;
    font-size: 24px;
    color:white;
    text-align: center;
    border:1px solid black;
}

[class*="col-"]{
    width: 98%;
}

/* Media Querries which are triggered when condition mentioned in brackets is encountered */


/* when width of screen is greater than equal to 1200px the following css is applied */

@media (min-width: 1200px){
    [class*="col-"]{
        height:400px;
    }
    .col-3{
        width:23%;
    }
    .col-6{
        width:46%;
    }
} 

@media (min-width: 1000px) and (max-width:1199px){
    [class*="col-"]{
        height:400px;
    }
    .col-3{
        width:22.5%;
    }
    .col-6{
        width:42%;
    }
}

@media (min-width: 750px) and (max-width:999px){
    [class*="col-"]{
        height:400px;
    }
    .col-3{
        width:22%;
    }
    .col-6{
        width:43%;
    }
}