css phantom cache
this is not an optimal solution.
You are actually dealing with 2 levels of cache: the server's and the browser's. What you just did is tell your browser to only cache your CSS files for 1 second. So anytime someone comes to your website, the browser will have to ask the server again for the CSS instead of leveraging the cache.
You should set that value back to what it was to improve on user experience.
Now concerning your problem, it is just a matter of cleating the browser's cache.
One easy way is to reload your page by clicking Ctrl + F5 on your keyboard.
Another way, if you're using Chrome (I didn't try other browsers) is to open the developers' tools by clicking F12. Once they're open, if you push the browser's reload button and keep it pushed, a drop-down will appear with 3 options. The last one will be "Empty cache and hard reload". This will clear the cache and make your CSS changes appear right away.
Hope that helps