styles.css

@media (min-width: 1px) {
    body {
        display: block;
        margin:0 auto;
        font-family: 'IBM Plex Sans', sans-serif;
        padding-left: 20px;
        font-size: 1em;
        padding-right: 20px;
        padding-bottom: 20px;
        width: 600px;
    }
}

@media (min-width: 840px) {
    body {
        display: block;
        margin:0 auto;
        font-family: 'IBM Plex Sans', sans-serif;
        padding-left: 20px;
        font-size: 1.2em;
        padding-right: 20px;
        padding-bottom: 20px;
        width: 800px;
    }
}

@media (min-width: 1040px) {

    body {
        display: block;
        margin:0 auto;
        font-family: 'IBM Plex Sans', sans-serif;
        padding-left: 20px;
        font-size: 1.2em;
        padding-right: 20px;
        padding-bottom: 20px;
        width: 1000px;
    }
}

@media (min-width: 1px) {
    .large-img {
        width: 600px;
    }
}

@media (min-width: 800px) {
    .large-img {
        width: 800px;
    }
}


p {
    margin: 0;
    margin-bottom: 1em;
    margin-top: 1em;
}

h1, h2, h3, h4, h5 {
    margin-top: 1em;
    margin-bottom: 1em;
}

pre {
    background-color: #eee;
    padding-top: 1em;
    padding-bottom: 1em;
    padding-left: 1em;
    padding-right: 1em;
    white-space: pre-wrap;       /* Since CSS 2.1 */
    white-space: -moz-pre-wrap;  /* Mozilla, since 1999 */
    white-space: -pre-wrap;      /* Opera 4-6 */
    white-space: -o-pre-wrap;    /* Opera 7 */
    word-wrap: break-word;       /* Internet Explorer 5.5+ */
}

code {
    background-color: #eee;
    word-wrap: break-word;
}

.header {
    background-color: rgb(53, 53, 53);
    border-bottom: lightcoral;
    border-bottom-style: solid;
    border-bottom-width: 5px;
    color: #fff;
    display: flex;
    height: 3em;
    justify-content: space-between;
    line-height: 3em;
    width: 100%;
}

.header-title {
    padding-left: 2em;
}

.header-nav {
    padding-right: 2em;
}

.content-container {
    display: flex;
    justify-content: space-between;
    margin-top: 2em;
    width: 100%;
}

.content-body {
    padding-left: 2em;
    text-align: justify;
    width: 80%;
}

.content-body p {
    margin-bottom: 2em;
}

.content-body h1, h2, h3, h4, h5 {
    margin-bottom: 1em;
}

.content-nav {
    width: 17%;
}

.content-nav h1 {
    font-size: 1em;
    margin-bottom: .5em;
}

.content-nav h2 {
    font-size: .7em;
    padding-left: 1em;
}

li {
    margin: 1em 0;
}