/* All <sections> to have 20px margin underneath */
section {
    margin-bottom: 20px;
}

/* The second <section> should have a 20px margin on top */
section:nth-of-type(2) {
    margin-top: 20px;
}

/* The <div> should have a 20px padding on top */
div {
    padding-top: 20px;
    background-color: lightgray;
}

/* All sections and div to have a padding of 5px underneath */
section, div {
    padding-bottom: 5px;
}

/* All text in the document to be set at a font size of 16px */
body {
    font-size: 16px;
}

/* All paragraphs under the <div> element needs to be set at 20px */
div p {
    font-size: 20px;
}

/* In the second section, all paragraphs after the first one should have an indent of 40px */
section:nth-of-type(2) p:not(:first-child) {
    text-indent: 40px;
}

/* In the fourth section, the second list item in the 1st list should have an underline */
section:nth-of-type(4) ul:first-child li:nth-child(2) {
    text-decoration: underline;
}

/* On hovering over the above, make the underline into a strikethrough */
section:nth-of-type(4) ul:first-child li:nth-child(2):hover {
    text-decoration: line-through;
}

/* Hovering over the third section changes the background of the fourth section */
section:nth-of-type(3):hover + section {
    background-color: lightblue;
}