title: How to have a text input with padding fill its container
body: <p>Of course, <code>width: 100%</code> on a block element fills the container, but only if border, padding, and margin are zero. Putting such an <code>input</code> in a containing <code>div</code> with padding does the trick, but I'm curious why simply <code>input {display: block; width: auto;}</code> doesn't work. Suggestions?</p>