JSFiddle - React, Tailwind, and code Playground

HTML

<body>      
        <div id="header">        
                <h1>Test Text but it's not inside the actual div...</h1>
        </div>
        <div id="content">
            <div id="topcontent">
                <img src="http://www.curiousfix.com/wp-content/uploads/2013/06/only_god_forgives_xxlg-2000x2964.jpg" id="left" >                    
                <img src="http://www.curiousfix.com/wp-content/uploads/2013/06/only_god_forgives_xxlg-2000x2964.jpg" id="right"/>   
                <img src="http://typographica.org/wp-content/uploads/2009/04/Lakside-styles-315x165.png" id="mid" />
            </div>
            </br>
            <div id="botcontent">
                <div class="slidercontainer">                      
                    <div id="area">
                        <div id="knob"></div>

                    </div>
                </div>
            </div>
        </div>
        <div id="footer">
            <img src="http://www.duv-ev.de/images/Leiste_Impressum_511x127_rgb-srgb_72.jpg"/>
        </div>

CSS

body,
html {
    height: 98%;
}
#header {
    height: 15.69%;
    background-color: gray;
    line-height:  15.69%;
}

#header h1{
    text-align: center;
    color: white;    
    vertical-align: middle;
}

#content{
    height: 71.16%;
    left:0;
    margin-left: 15%;
    margin-right: 15%;
    right:0;       
}
#topcontent{
    height:56.245%; 
}

.slidercontainer{
    width: 100%;
}
#botcontent{
    height: 43.755%;
}

img {
    max-height:100%;
}

#footer{
    text-align: center;
    background-color: gray;
    height: 13.15%;
}


#left{
    float:left;
    margin-left: 10%;
    max-width: 30%;
}

#right{
    float: right;
    max-width: 30%;
    margin-right:10%;
}
#mid{
    display: block;
    margin-left: auto;
    margin-right: auto;
    max-width: 10%;
}

#area {
    background: gray;
    height:6em;
    width: 100%;  
    border-radius: 1em;
}

#knob {      
    height: 6em;
    width: 6em;
    background: orange;
    border-radius: 1em;
}