body {
    width: 800px;
    margin: auto;
}

h1 {
    padding: 20px;
    background-color: olivedrab;
}

#top_img {
    background-color: coral;
    margin: 2em;
    width: 20em;
    height: 20em;
    float: left;
}

section {
    clear: left;
}

#second {
    background-color: cornflowerblue;
}

#cols {
    column-count: 3;
}

#btt_button {
    position: fixed;
    bottom: 20px;
    right: 30px;
    z-index: 99;
    border: none;
    outline: none;
    background-color: rgb(255, 0, 106);
    color: white;
    cursor: pointer;
    padding: 15px;
    border-radius: 10px;
    font-size: 1.3em;
    display: none;
}