Bootstrap’s weight
Bootstrap’s
minified CSS weighs around 130 KB, which is quite a lot for what is essentially just base elements and grid structure. If you’re actually going to start using Bootstrap in a template, then you’ll need to customize it. By customize, we mean that you’ll need to override styles since it is
not possible to modify everything using on LESS variables, which justs adds even more lines to the final CSS code. Then, if you want to be fully compatible with Joomla! you should load the Bootstrap library from the media/jui directory, which means that you will use the full-fat Bootstrap styles even when you don’t need most of them. To add insult to injury, they are loaded on every single page reload, and you’re not even using them!
Bootstrap isn’t just CSS, it’s
JavaScript too, which adds an
extra 29KB to the overall weight. All in all, you’re looking at a bare minimum of
160 KB to create a template using the default Joomla! Bootstrap library. Now add in your custom styles and override rules, and your CSS may be too heavy to lift, as it were.