index.css

body {
    background-image: url("https://cdn.magicawakened.com/app/uploads/2023/04/18143024/WBG_Mystical_Wallpapers_Hogwarts_16x9_03_LA-1200x900.png");
    background-size: cover;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    font-weight: bold;
    color:blanchedalmond;
    text-align: center;
    height: 100vh;
}

h1 {
    margin-top: 10px;
    margin-bottom: 10px;
}

h2 {
    font-size: 50px;
    margin-top: 0;
    margin-bottom: 20px;
}

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

#increment-btn {
    background:coral
}

#save-btn {
    background: darkgreen;
}
.myapp
{
    background:teal;
    border: 3px solid;
    border-radius: 15px;
    max-width: 80%;
    margin: auto;
    padding: auto;
}