JSFiddle - React, Tailwind, and code Playground

HTML

<nav>
        <div id="nav-container">
            <ul>
                <li class="select"><a href="">Home</a></li>
                <li><a href="">Gallery</a></li>
                <li><a href="">Song</a></li>
                <li><a href="">About</a></li>
                <li><a href="">Login</a></li>
                <li><a href="">Register</a></li>
            </ul>
        </div>
    </nav>
    <header>
        <div id="header-container">
            <div class="header-container-left">
                <img src="http://lorempixel.com/250/200/sports/">
            </div>
            <div class="header-container-right">
                <h1>This is my first photoshop web design :)</h1>
                <button class="header-button">More info <3</button>
            </div>
        </div>
    </header>

CSS

body {margin:0px;}
nav{
    width: 100%;
    height: 50px;
    background-color: #54598f;
}

#nav-container{
    width: 1200px;
    height: 50px;
    margin: 0 auto;
    background-color: #54598f;
}

#nav-container li, a{
    display: inline-block;
    text-decoration: none;
    color: white;
    font-family: 'agentorange';
    font-size: 17pt;
    margin-right: 10px;
    line-height: 50px;
    text-align: center;
}

.select a{
    color: white;
    background-color: #363a60;
    padding-left: 15px;
    padding-right: 15px;
}

/*header*/

header{
    width: 100%;
    height: 250px;
    background: url('http://lorempixel.com/400/300/nature/') center;
    background-size:cover;
}

#header-container{
    width: 1200px;
    height: 250px;
    margin: 0px auto;
}
.header-container-left{
    width: 270px;
    height: 250px;
    float: left;
    margin-top: 30px;
}

.header-container-right{
    width: 930px;
    height: 250px;
    margin-left: 280px;
    padding-top: 33px;
}
.header-container-right h1{
    font-family: 'agentorange';
    font-size: 18pt;
    color: white;
}
.header-button{
    border-radius: 10px;
    background-color: rgb( 54, 58, 95 );
    box-shadow: 2.5px 4.33px 5px 0px rgb( 0, 0, 0 );
    width: 220px;
    height: 50px;
    border: none;
    font-size: 16pt;
    color: white;
    font-family: 'agentorange';
    margin-top: 20px; 
}