After playing around with this some I think I found a way to turn the radio buttons into tabs using a label tag.
With the css as follows:
.sheet-character-sheet { display: none; }
.sheet-expand:checked ~ .sheet-show,
.sheet-expand:not(:checked) ~ .sheet-hide
{
display: block;
}
And the html:
<label style="position:absolute;left:2px;top:4em;">
<input type="radio" value="1" name="attr_tab" style="display:none;" checked/>
<div style="float:left;">
<table style="width:64px;border-top:thin solid gray;border-right:thin solid gray;border-left:thin solid gray;border-radius: 3px 3px 0px 0px;">
<tr>
<td>tab1</td>
</tr>
</table>
<table style="width:800px;border-left:thin solid gray;border-right:thin solid gray;border-bottom:thin solid gray;">
<tr>
<td>
tab1 stuff goes here
</td>
</tr>
</table>
</div>
<div>
<table style="width:64px;border:thin solid gray;background-color:#acacac;color:#555555;">
<tr>
<td>tab1</td>
</tr>
</table>
</div>
</label>
<label style="position:absolute;left:64px;top:4em;">
<input type="radio" value="1" name="attr_tab" style="display:none;" />
<div style="float:left;">
<table style="width:64px;border-top:thin solid gray;border-right:thin solid gray;border-left:thin solid gray;">
<tr>
<td>tab2</td>
</tr>
</table>
<table style="width:800px;position:relative;left:-62px;border-left:thin solid gray;border-right:thin solid gray;border-bottom:thin solid gray;">
<tr>
<td>
tab2 stuff goes here
</td>
</tr>
</table>
</div>
<div>
<table style="width:64px;border:thin solid gray;background-color:#acacac;color:#555555;">
<tr>
<td>tab2</td>
</tr>
</table>
</div>
</label>
<label style="position:absolute;left:128px;top:4em;">
<input type="radio" value="1" name="attr_tab" style="display:none;" />
<div style="float:left;">
<table style="width:64px;border-top:thin solid gray;border-right:thin solid gray;border-left:thin solid gray;">
<tr>
<td>tab3</td>
</tr>
</table>
<table style="width:800px;position:relative;left:-126px;border-left:thin solid gray;border-right:thin solid gray;border-bottom:thin solid gray;">
<tr>
<td>
tab3 stuff goes here
</td>
</tr>
</table>
</div>
<div>
<table style="width:64px;border:thin solid gray;background-color:#acacac;color:#555555;">
<tr>
<td>tab3</td>
</tr>
</table>
</div>
</label>