A good page for the standard BS media queries is [[https://scotch.io/tutorials/default-sizes-for-twitter-bootstraps-media-queries|Default Sizes for Twitter Bootstrap Media Queries]]

and another more detailed page is [[https://css-tricks.com/snippets/css/media-queries-for-standard-devices/|Media Queries for Standard Devices]]

Usage example:
<code>
@media screen and (min-width: 768px) {.rwd-hide {display:none;}}
@media screen and (max-width: 992px) {.em-show {display:none;}}
@media screen and (max-width: 768px) {.rwd-show {display:none;}}
</code>
Also, to hide things, use
<code>
visibility: hidden // use 'collapse' for table elements
</code>

Standard breakpoints:\\
320px\\
480px\\
768px\\
992px\\
1200px\\