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

body {
    font-family: 'Helvetica Neue', Arial, Helvetica, sans-serif;
    padding: 1rem;
    background-color: whitesmoke;
    width: 100vw;
    height: 100vh;
    box-shadow: 0 0 10rem slateblue inset;
}

h1,
h2,
h3,
h4 {
    font-size: 1rem;
    font-weight: 400;
}

.bubble {
    position: absolute;
    width: 100px;
    height: 100px;
    border-radius: 50%;
    background-size: cover;
    background-position: center;
    transition: transform 0.1s;
    border: 1px dashed gray;
    box-shadow: 0 0 1rem inset slateblue;
    filter: grayscale(1);
    transition: 2s;
    cursor: pointer;
}

.bubble:hover {
    filter: grayscale(0);
    transform: rotate(360deg);
}

.go-back {
    background-color: white;
    display: flex;
    align-items: center;
    justify-content: center;
}