I seem to have additional vertical space, the scrollbar shows (it looks about 60 pixels). I also want to add header type divs to each box but they keep shifting.
Here is a link to the main stuff
https://jsfiddle.net/rocky050371/bcm2w6rb/
Surrounding it is the master page
<body>
<form id="SiteMasterForm" runat="server">
<asp:ScriptManager ID="ScriptManager" runat="server"></asp:ScriptManager>
<div>
<div class="siteheader">
<div class="headercolumn1">
<div>
<asp:ImageButton ID="ibRFIDLogo" CssClass="rfidlogo" runat="server" AlternateText="RFID Discovery Logo" ImageUrl="/Images/RFiD_Discovery_Logo.jpg" OnClick="ibRFIDLogo_OnClick" />
</div>
</div>
<div class="headercolumn2">
<p class="companyline1"></p>
<p class="companyline2"></p>
</div>
<div class="headercolumn3">
<p class="companyline1"></p>
<p class="companyline2">Administrator</p>
</div>
<div class="headercolumn4">
<asp:ImageButton ID="ibLogout" ImageUrl="~/Images/log_out_64.png" OnClick="ibLogout_OnClick" runat="server" />
</div>
</div>
<div>
<asp:ContentPlaceHolder ID="sitecontent" runat="server">
</asp:ContentPlaceHolder>
</div>
</div>
</form>
</body>
