Why does increasing padding in this <a> increase the vertical margin? - google-chrome

Question

This is probably the most unusual CSS behavior I have ever seen:
I have an extremely simple table that consists of two cells - one with plain text and another with a link:
<div class="content">
<table>
<tr>
<td>
Hello, world!
</td>
<td>
Hello, world!
</td>
</tr>
</table>
</div>
I have also applied the following CSS to the table:
div.content {
background-color: green;
height: 100px;
}
table td {
background-color: red;
height: 50px;
}
table td a {
background-color: orange;
box-sizing: border-box;
display: block;
height: 100%;
padding: 8px;
width: 100%;
}
When rendered in Chrome 28, I see the following:
Why is there a large amount of red above and below the link? I have specified height: 100%; for the link, so it should be taking up the full height of the <td>, which has an explicit height.

Answer 1

It's definitely an issue with the box-sizing:border-box attribute. My guess is that putting that inside a table cell (which is treated differently then a div) is confusing the browser. Often, new techniques + old techniques don't mix.
I would suggest doing the following:
table td a {
background-color: orange;
display: block;
height: 100%;
padding: 8px;
}
The width:100% was unneeded since the table cell already expanded to the text width + padding width. For some reason, it doesn't seem to add the padding to the height 100% with the table cell (go figure, weirdness with tables! lol). If you need it to expand to a larger table cell width, I would suggest then putting the width:100% back but then ditch the horizontal padding (i.e. put padding:8px 0px;).

Answer 2

As far as I think its the box-sizing attribute causing this, change your css to:
table td a {
background-color: black;
height: 100%;
display:block;
margin: 0;
padding: 0px;
width: 100%;
padding-top: 12px;
}
Hope that helps;

Answer 3

Add This Code to table td:
display:inline-block;
because There is some difference between tables and divisions in box modeling.
you must set display-block on any none-block element for apply box-model style.

Answer 4

Try setting height in px for a as
table td a {
background-color: orange;
box-sizing: border-box;
display: block;
height: 50px;
padding: 8px;
width: 100%;
}

Answer 5

here's an example of a jury-rig: http://jsfiddle.net/rTAwd/
We're using a line height to adjust the cell's height, so we don't need to mess with vertical alignment, and relying on a wrapper div to provide our background and padding.
<div class="content">
<table>
<tr>
<td>Hello, world!</td>
<td>
<div> Hello, world!</div>
</td>
</tr>
</table>
</div>
css
div.content {
background-color: green;
height: 100px;
}
table td {
background-color: red;
}
table td div a {
line-height: 2em;
}
table td div {
background-color: orange;
padding: 8px;
}

Answer 6

I think its a bug, i had the same issue a while ago, if you want the text to vertically align in the middle, instead of using display:block on the <a> tag use display:table and use border-spacing instead of padding, like this:
table td a {
background-color: orange;
display: table;
height: 100%;
border-spacing: 8px 13px;
}
I removed the width:100% too since it will do it by default, you can see an example here.
border-spacing is the CSS property for cellpadding.