style.css

body {
    font-family: 'Lato', sans-serif;
}

img {
    max-width: 800px;
    border: 3px solid black;
    display: block;
    margin: 10px 0px;
}

#header {
    background-color: black;
    padding: 5px;
    padding-left: 30px;
    color: white;
}

#header a {
    text-decoration: none;
}

#header a:visited {
    text-decoration: none;
    color: white;
}

#header h2 {
    font-style: italic;
}

#menu a {
    text-decoration: none;
    list-style-type: none;
    text-transform: uppercase;
    color: white;

}

#menu ul {
    display: flex;
    justify-content: space-evenly;
}

#menu li {
    padding-top: 16px;
    background-color: black;
}

#menu {
    height: 54px;
    width: 150px;
    background-color: black;
    width: 100%;
}

body>h2 {
    text-align: center;
    text-decoration: underline;
    font-size: 40px;
}

.content {
    width: 1184px;
    margin-left: auto;
    margin-right: auto;
    padding: 20px;
    margin-top: 20px;
    border: 10px solid black
}

table {
    margin-left: auto;
    margin-right: auto;
    border-collapse: collapse;
    border: 1px solid black;
    margin-top: 10px;
    margin-bottom: 20px;
}

tr,
td {
    border: 1px solid black;
    min-width: 150px;
}

th {
    background-color: black;
    color: white;
}

.subsection {
    margin-left: auto;
    margin-right: auto;
    padding: 10px;
    border: 10px solid lightgrey;
}

a,
a:visited {
    text-decoration: none;
    color: black;
}

.theoryImg {
    margin-left: auto;
    margin-right: auto;
}

dfn{
font-weight:800;
}