5px extra margin getting added to the bottom of each div - css

Question

I am trying to design a simple header to a page in css. I planned to stack two divs on top of each other. The top one has many tabs and the bottom one is a plain solid single image div. But when rendering i see that an extra 5px is getting added to the the heights of both these divs. So i am not able to place the bottom on exactly on top of the other one.
There is a 5px bottom margin automatically. I tried negative margins, reset the global margins and paddings to zero. Still no use.
Heres the code.
<div class ="main_nav">
<div class="first_tab">
<img src ="images/startup/tab1_brown.png" height="25" width="90" alt="Temp" />
</div>
<div class = "ind_tab">
<img src ="images/startup/tab1_orange.png" height="25" width="90" alt="Temp"/>
</div>
<div class = "ind_tab">
<img src ="images/startup/tab1_brown.png" height="25" width="90" alt="Temp" />
</div>
</div>
<div class="lock">
<img src ="images/startup/divbg_new.png" alt="Temp" />
</div>
CSS:
*{ margin:0; padding:0; }
ul.master_navigation
{
font-size: 125%;
font-weight: bold;
text-align: center;
list-style: none;
margin: 0.5em 0;
padding: 0;
}
ul.master_navigation li
{
display: inline-block;
padding: 0 1%;
}
a
{
color: #08f;
font-weight: bold;
text-decoration: none;
}
a:visited
{
color: #88f;
}
a:hover
{
color: #f00;
}
p
{
text-align: justify;
}
p.cent
{
text-align: left;
}
div.header
{
height: 200;
}
div.main_nav
{
display: inline-block;
height: 25;
width: 900;
padding: 0;
margin: 0;
vertical-align: bottom;
}
div.first_tab
{
height: 25;
float: left;
}
div.ind_tab
{
height: 25;
float: left;
margin-left: -10px;
z-index: -5;
}
div.lock
{
margin-top: -100;
height: 91;
width: 900;
padding: 0;
margin: -5;
}
body
{
width:900px;
max-width: 100%;
margin: auto;
padding: 0;
background-image:url(images/startup/bg_2.gif);
background-repeat:repeat-x;
}
.pad
{
padding: 0;
margin: 0;
}
Here's the link to the page
http://net4.ccs.neu.edu/home/pradep/
Ive been spending too much time on this. Please help.

Answer 1

Ege's answer was very useful for me. I have spent hours to find the reason of a bottom padding of some images in div's. It was the line-height. Set it to 0px on the interesting areas:
.divclass {
line-height: 0px; /* crucial for bottom padding 0 !!! */
}

Answer 2

I think your problem is the line-height. Yup, there it is. Just added line-height:0, on firebug and they stuck together.
The thing about inline-blocks is that they behave just like any inline text, you also have a similar issue on the navigation below, because you pressed enter in your code, it will render it as a non-breaking space and add extra x margins to the right and left sides as well. X here will depend on the font size.
In order to solve this, you can either close and open tags on the same line like below:
<div>
.
.
.
</div><div>
.
.
.
</div>
or you can set the font-size and line-height to 0, but thats not always possible if you don't have other selectors inside that div.

Answer 3

You need to specify units on your CSS declarations.
http://jsfiddle.net/m7YCW/
div.main_nav
{
display: inline-block;
height: 25px; /* set px */
width: 900;
padding: 0;
margin: 0;
vertical-align: bottom;
}
Learn to make use of your developer tools in Chrome, if you had right mouse buttoned on the elements and chosen -> inspect it would bring up the dev tools. You can then view the 'metrics' and 'computed styles' areas to see that main_nav was rendering as 30px instead of 25px and also that there was a warning symbol next to the 25 css declaration and it was being explicitly dropped.

Answer 4

Try setting vertical-align:bottom on the images.