For browsers that comply with the CSS3 standard, you can use thewhite-space-collapsing:discardattribute

See:http://www.w3.org/TR/2010/WD-css3-text-20101005/#white-space-collapsing

Alternatively, you can useflexboxto achieve many of the layouts you might have previously achieved using inline-block:https://css-tricks.com/snippets/css/a-guide-to -flexbox/

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Since this answer has become quite popular, I'm rewriting it.

Let us not forget the actual question asked:

This problem can be solved using just CSS, but there is no completely stable CSS fix.

The solution I proposed in my original answer was to addfont-size: 0to the parent element and then declare a reasonablefont-sizein the child element.

http://jsfiddle.net/thirtydot/dGHFV/1361/

This works in the latest versions of all modern browsers. It works in IE8. It doesn't work in Safari 5, but works in Safari 6. Safari 5 is almost a dead browser (0.33%, August 2015).

Most issues related to relative font sizes are not complicated.

However, if you are free to change the HTML (most people are), this is a reasonable solution, but not one I would recommend.

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As an experienced web developer, this is how I actually solved this problem:

 FooBar 

Yes, that's it. I removed the spaces in the HTML between inline block elements.

It's easy. this is very simple. It works everywhere. This is a pragmatic solution.

You sometimes have to think carefully about the source of whitespace. Will spaces be added if I append another element using JavaScript? No, if you do it correctly.

Let's take a magical journey and learn about some different ways to remove spaces, using some new HTML:

 
Item 1
 
Item 2
 
Item 3
 

• You can do what I usually do:

   
  Item 1
  Item 2
  Item 3
   

http://jsfiddle.net/thirtydot/dGHFV/1362/

• Or, do this:

   
  Item 1
  Item 2
  Item 3
   

• Or, use comments:

   
  Item 1
  Item 2
  Item 3
   

• Or if you use PHP or something similar:

   
  Item 1
  Item 2
  Item 3
   

• Alternatively,you can evenomitcertainclosing tags entirely (supported by all browsers):

   
  Item 1 
  Item 2 
  Item 3 

Now that I've bored you with "thirtydot's thousand different ways to remove spaces", I hope you've forgottenfont-size: 0.