body {
    text-align: center;
    margin: 0;
    padding: 0;
}


#app {
    margin: 20px;
}

#abacus-canvas {
    display: block;
    margin: 20px auto;
    border: 1px solid #ccc;
}

#settings, #flashcards {
    max-width: 600px;
    margin: auto;
}

.section {
    margin: auto;
    max-width: 600px;
}


#tutorial {
    margin-top: 20px;
    text-align: left;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
    font-size: 16px;
    line-height: 1.5;
}

#tutorial h2 {
    text-align: center;
}

#tutorial h3 {
    margin-top: 20px;
}

#tutorial p {
    margin-bottom: 10px;
}

#tutorial ul {
    list-style-type: disc;
    margin-left: 20px;
    margin-bottom: 20px;
}

.perspective-1000 {
    -webkit-perspective: 1e3px;
    -moz-perspective: 1e3px;
    perspective: 1e3px;
}

.transform-style-preserve-3d {
    -moz-transform-style: preserve-3d;
    transform-style: preserve-3d;
    -webkit-transform-style: preserve-3d;
}