style.css

*{
    padding: 0;
    margin: 0;
    box-sizing: border-box;

}
body{
  
    margin-top: 50px;
    /* background-color: #05386b; */
    background-image: linear-gradient(30deg,tomato,lightblue);
    background-size: cover;
    /* background-repeat: no-repeat; */
}
.container-fluid{
border: 2px solid gray;
border-radius: 16px;
padding: 50px;
text-align: center;
box-shadow: 10px 10px 20px gray;
/* background-image: linear-gradient(30deg,orange,tomato,tomato) */
background-color: #ffffff;
animation-duration: 10s;
animation-name: animation;
animation-iteration-count: infinite;
}
@keyframes animation {
    0%{
        border-color: tomato;
    }
    10%{
        border-color: rgb(153, 0, 0);
    }
    20%{
        border-color: rgb(138, 138, 138);
    }
    30%{
        border-color: rgb(5, 79, 92);
    }
    40%{
        border-color: rgb(71, 181, 255);
    }
    50%{
        border-color: rgb(0, 85, 124);
    }
    60%{
        border-color: rgb(101, 255, 109);
    }
    70%{
        border-color: rgb(255, 175, 71);
    }
    80%{
        border-color: rgb(106, 26, 255);
    }
    90%{
        border-color: rgb(255, 71, 71);
    }
    100%{
        border-color: rgb(71, 255, 224);
    }
}
h3{
    font-family:cursive;
    padding-bottom : 30px;
    /* color: white; */
    color: rgb(28, 219, 210);
    text-shadow: 5px 5px 20px gray;
}
.joke{
    margin-bottom: 20px;
    padding: 10px 50px;
    color: tomato;
    /* color: white; */
    font-size: 18px;
    font-weight: 700;
}
.btn{
    background-color:#14579b;
    /* padding: 8px;
    /* border: 2px solid gray; */
    /* border-radius: 4px; */
    color: white;
    box-shadow: 7px 10px 20px gray;
    font-size: large;
    cursor: pointer;

   
}
/* .btn i:hover{

} */
.btn:hover{
    /* transform: scale(1.1); */
    transform: translate(10px);
    transition-duration: 0.5s;
}