Customizing Bootstrap CSS template

Question

I am just getting started with Bootstrap from Twitter and am wondering what the ‘best practices’ is for customization. I want to develop a system that will take advantage of all the power of a css template (Bootstrap or other), be completely (and easily) modifiable, be sustainable (ie – when the next version of Bootstrap is released from Twitter I don’t have to start over.

For example, I want to add background images to the top navigation. It looks like there are 3 ways to go about this:

1. Modify the .topbar classes in bootstrap.css . I don’t particularly like this because I will have lots of .topbar items and I don’t necessarily want to modify them all the same way.
2. Create new classes with my background images and apply both styles (the new and the bootstrap to my element). This may create style conflicts, which could be avoided by stripping the .topbar class into separate classes and then only using the pieces that are not stepped on by my custom class. Again this requires more work than I think should be necessary and while it is flexible, it won’t allow me to easily update bootstrap.css when Twitter releases the next installment.
3. Use variables in .LESS to achieve the customization. Offhand this seems like a good approach but having not used .LESS I have concerns about compiling css on the client and about code sustainability.

Though I am using Bootstrap, this question can be generalized to any css template.

Thanks in advance for input.

Answer 1

I recently wrote a post about how I've been doing it at Udacity for the last couple years. This method has meant we've been able to update Bootstrap whenever we wanted to without having merge conflicts, thrown out work, etc. etc.

The the post goes more in depth with examples, but the basic idea is:

• Keep a pristine copy of bootstrap and overwrite it externally.
• Modify one file (bootstrap's variables.less) to include your own variables.
• Make your site file @include bootstrap.less and then your overrides.

This does mean using LESS, and compiling it down to CSS before shipping it to the client (client-side LESS if finicky, and I generally avoid it) but it is EXTREMELY good for maintainability/upgradability, and getting LESS compilation is really really easy. The linked github code has an example using grunt, but there are many ways to achieve this -- even GUIs if that's your thing.

Using this solution, your example problem would look like:

• Change the nav bar color with @navbar-inverse-bg in your variables.less (not bootstrap's)
• Add your own nav bar styles to your bootstrap_overrides.less, overwriting anything you need to as you go.
• Happiness.

When it comes time to upgrade your bootstrap, you just swap out the pristine bootstrap copy and everything will still work (if bootstrap makes breaking changes, you'll need to update your overrides, but you'd have to do that anyway)

Blog post with walk-through is here.

Code example on github is here.

Answer 2

The best thing to do is.

1. fork twitter-bootstrap from github and clone locally.

they are changing really quickly the library/framework (they diverge internally. Some prefer library, i'd say that it's a framework, because change your layout from the time you load it on your page). Well... forking/cloning will let you fetch the new upcoming versions easily.

2. Do not modify the bootstrap.css file

It's gonna complicate your life when you need to upgrade bootstrap (and you will need to do it).

3. Create your own css file and overwrite whenever you want original bootstrap stuff

if they set a topbar with, let's say, color: black; but you wan it white, create a new very specific selector for this topbar and use this rule on the specific topbar. For a table for example, it would be <table class="zebra-striped mycustomclass">. If you declare your css file after bootstrap.css, this will overwrite whatever you want to.