style.css

body {
    font-family: 'Helvetica Neue', Verdana, Helvetica, Arial, sans-serif;
    max-width: 800px;
    margin: 0 auto;
    padding: 72px 0;
    -webkit-font-smoothing: antialiased;
    font-size: 1.125em;
    color: #333;
    line-height: 1.5em;
}

h1, h2, h3, h4, h5, h6 {
    line-height: 1;
}

h1 {
    font-size: 2.5em
}

h2 {
    font-size: 1.85em;
    padding-bottom: 0.3em;
    border-bottom: 1px solid #eaecef;
}

h3 {
    font-size: 1.35em
}

h4 {
    font-size: 1.2em
}

h5 {
    font-size: 1.15em
}

h6 {
    font-size: 1.1em
}

a {
    text-decoration: none;
    color: #4165a2;
}

a:hover {
    border-bottom: 1px dotted black;
}
pre {
    font-size: 16px;
    padding: 16px 18px;
    border-radius: 5px;
    background-color:  rgb(240, 242, 245);
}

*:not(pre) > code {
    font-size: 1.15em;
    padding: 3px 5px;
    border-radius: 5px;
    background-color:  rgb(240, 242, 245);
}

.hidden {
    display: none;
}