Never add padding to an element with a defined width due to IE errors. Instead, add padding to the element's children. (Budd page 30)

Margin-collapsing only happens with vertical boxes in the normal flow. (Budd 33)

Vertical spacing will not affect an inline box, but setting the line-height will. (Budd 33)

In IE 5.5 and 6, if you try to set the position of an absolute box relative to a relatively-positioned box, you need to specify the width and height of that relatively-pos. box. (Budd 36)

All about clearing on page 41.

More to come... Please add your own.

Most of these come from the book "CSS Mastery: Advanced Web Standards Solutions," a must-read by Andy Budd (seriously, even if you've used CSS for years, you'll learn a good deal of new things from this book; beginners should read this immediately after learning a bit of CSS).

CSS oddities and their fixes

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