index.css

body {
    background-image: url("butterflies.jpeg");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    height: 100vh;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    font-weight: bold;
    text-align: center;
    
}

#container-div {

    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%,-50%);
}

h1 {
    margin-top: 10px;
    margin-bottom: 10px;
    text-shadow: 0 0 10px purple
}

h2 {
    font-size: 50px;
    margin-top: 0;
    margin-bottom: 20px;
    text-shadow: 0 0 10px purple
}

p {
    color: black;
    text-shadow: 0 0 10px purple
}

button {
    border: 2px solid purple;
    padding-top: 10px;
    padding-bottom: 10px;
    color: white;
    font-weight: bold;
    width: 200px;
    margin-bottom: 5px;
    border-radius: 15px;
}

#increment-btn {
    background: darkred;
    
}

#save-btn {
    background: darkgreen;
}

#reset-btn {
    background: teal;
}