style.css

body {
    margin: 0;
    background: linear-gradient(to left bottom, #abf479, #A95EA3, #DC3A79, #1686CD);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: center;
    font-family: monospace;
}

.container {
    background-color: rgba(255, 255, 255, .3);
    padding: 20px;
    box-shadow: 0 6px 10px rgba(0, 0, 0, .3);
    border-radius: 15px;
    width: 70%;
    text-align: center;
    color: darkgreen;
}

.heading {
    font-size: 35px;
    font-weight: 200;
    font-family: Impact, Haettenschweiler, 'Arial Narrow Bold', sans-serif;
    text-shadow: 3px 4px 2px rgba(0, 0, 0, .3);
    letter-spacing: 2px;
}

.joke {
    font-size: 25px;
    font-weight: 500;
    margin: 40px
}

.btn {
    font-size: 18px;
    font-weight: 550;
    border-radius: 8px;
    cursor: pointer;
    padding: 10px;
    background-color: green;
    border-color: rgb(255, 255, 255);
    text-transform: uppercase;
    width: 200px;
    color: white;
    box-shadow: 6px 6px 12px rgba(0, 0, 0, 0.4);
    transition: background-color 0.3s, color 0.3s;
}

.btn:hover {
    box-shadow: 0 4px 15px 0 rgba(23, 168, 108, 0.75);
}