JSFiddle - React, Tailwind, and code Playground

HTML

<header class="clearfix">
    <div class="firstDiv">
        <img class="myImage" src="font.jpg">
    </div>
    <div class="secondDiv">
        <nav>
            <ul>
                <li><a href="index.php">Home</a>
                </li>
                <li><a href="page1.php">Page 1</a>
                </li>
            </ul>
        </nav>
    </div>
</header>

CSS

nav {
    display: block;
    width: 100%;
    overflow: hidden;
    text-align: center;
}
nav ul {
    padding: .7em;
    list-style: none;
    background: #2f2b23;
    box-shadow: 0 1px 0 rgba(255, 255, 255, .5), 0 2px 1px rgba(0, 0, 0, .3) inset;
    border: 3px solid black;
    /* added*/
    display: inline-block;
}
nav li {
    float:left;
}
nav a {
    float:left;
    padding: .8em .7em;
    text-decoration: none;
    color: black;
    text-shadow: 0 1px 0 rgba(255, 255, 255, .5);
    font: bold 1.1em/1'trebuchet MS', Arial, Helvetica;
    letter-spacing: 1px;
    text-transform: uppercase;
    border-width: 1px;
    border-style: solid;
    border-color: #black #BF7530;
    background: #BF4630;
}
nav a:hover, nav a:focus {
    outline: 0;
    color: #black;
    text-shadow: 0 1px 0 rgba(0, 0, 0, .2);
    background: #FFDB73;
}
nav a:active {
    box-shadow: 0 0 2px 2px rgba(0, 0, 0, .3) inset;
}
nav li:first-child a {
    border-left: 0;
    border-radius: 4px 0 0 4px;
}
nav li:last-child a {
    border-right: 0;
    border-radius: 0 4px 4px 0;
}
.firstDiv {
    border: 5px solid black;
    width:100px;
    height: 110px;
    float:left;
}
header{
    padding: 5px;
    background: #999;
}
.secondDiv {
    border-spacing: 15px;
    border: 4px solid black;
    background-color: #FF8700;
    float:left;
}

.clearfix:before,
.clearfix:after {
    content: " "; /* 1 */
    display: table; /* 2 */
}

.clearfix:after {
    clear: both;
}