What's the standard max width for CSS
<p>So I want the css to change when the user makes the window just a few tens of  pixels smaller. But I don't know what's the width I need to use.
My monitor is 1440x900, but other people have 1920x1080... and let's not forget about the 4K monitors.
What's the width that I put here?</p>

<pre><code>    @media screen and (max-width:.....?){}
</code></pre>