body{
    margin: 0;
    background-image: url("ai.gif");
    background-repeat: no-repeat;
    background-size: 2000px;
}
ul{
    list-style-type: none;
    margin: 0;
    padding: 0;
    width: 140px;
    background-color: #896C6C;
    position: fixed;
    height: 100%;
    overflow: auto;
}
li a{
    display: block;
    color: white;
    padding: 25px 16px;
    text-decoration: none;
}
li a.active{
    background-color: #F14A00;
    color: black;
}
li a:hover:not(.active){
    background-color: #E19898;
    color: rgb(177, 12, 12);
}
*{
    box-sizing: border-box;
}
.column{
    float: left;
    width: 25%;
    padding: 0 10px;
}
.row{
    margin: 5px;
}
.row::after{
    content: " ";
    display: table;
    clear: both;
}
@media screen and (max-width:600px){
    .column{
        width: 100%;
        display: block;
        margin-bottom: 20px;
    }
}
.card1{
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2);
    padding: 16px;
    text-align: center;
    background-image: url("ai2.jpg");
    background-repeat: no-repeat;
    background-size: 400px 300px;
    border-width: 10px;
    border-color: #DC143C;
}
.card2{
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2);
    padding: 16px;
    text-align: center;
    background-image: url("dl.jpg");
    background-repeat: no-repeat;
    background-size: 400px 300px;
    border-width: 10px;
    border-color: #DC143C;
}
.card3{
    box-shadow: 0 4px 8px 0 rgba(0,0,0,0.2);
    padding: 16px;
    text-align: center;
    background-image: url("nlp.jpg");
    background-repeat: no-repeat;
    background-size: 400px 300px;
    border-width: 10px;
    border-color: #DC143C;
}