How can I override Bootstrap CSS styles?

Asked 21/12, 2013 at 16:47 Answered 26/5, 2022 at 3:1

318

I need to modify bootstrap.css to fit my website. I feel it's better to create a separate custom.css file instead of modifying bootstrap.css directly, one reason being that should bootstrap.css get an update, I'll suffer trying to re-include all my modifications. I'll sacrifice some load time for these styles, but it's negligible for the few styles I'm overriding.

Hw do I override bootstrap.css so that I remove the style of an anchor/class? For example, if I want to remove all the styling rules for legend:

legend {
  display: block;
  width: 100%;
  padding: 0;
  margin-bottom: 20px;
  font-size: 21px;
  line-height: inherit;
  color: #333333;
  border: 0;
  border-bottom: 1px solid #e5e5e5;
}

I can just delete all that in bootstrap.css, but if my understanding about best practices on overriding CSS is correct, what should I do instead?

To be clear, I want to remove all those styles of legend and use parent's CSS values. So combining Pranav's answer, will I be doing the following?

legend {
  display: inherit !important;
  width: inherit !important;
  padding: inherit !important;
  margin-bottom: inherit !important;
  font-size: inherit !important;
  line-height: inherit !important;
  color: inherit !important;
  border: inherit !important;
  border-bottom: inherit !important;
}

(I was hoping there's a way to do something like the following:)

legend {
  clear: all;
}

Contempt answered 21/12, 2013 at 16:47 Comment(1)

Just make sure your own css loads after the bootstrap css. – Dike 12/9, 2022 at 20:18

612

Using !important is not a good option, as you will most likely want to override your own styles in the future. That leaves us with CSS priorities.

Basically, every selector has its own numerical 'weight':

100 points for IDs
10 points for classes and pseudo-classes
1 point for tag selectors and pseudo-elements
Note: If the element has inline styling that automatically wins (1000 points)

Among two selector styles browser will always choose the one with more weight. Order of your stylesheets only matters when priorities are even - that's why it is not easy to override Bootstrap.

Your option is to inspect Bootstrap sources, find out how exactly some specific style is defined, and copy that selector so your element has equal priority. But we kinda loose all Bootstrap sweetness in the process.

The easiest way to overcome this is to assign additional arbitrary ID to one of the root elements on your page, like this: <body id="bootstrap-overrides">

This way, you can just prefix any CSS selector with your ID, instantly adding 100 points of weight to the element, and overriding Bootstrap definitions:

/* Example selector defined in Bootstrap */
.jumbotron h1 { /* 10+1=11 priority scores */
  line-height: 1;
  color: inherit;
}

/* Your initial take at styling */
h1 { /* 1 priority score, not enough to override Bootstrap jumbotron definition */
  line-height: 1;
  color: inherit;
}

/* New way of prioritization */
#bootstrap-overrides h1 { /* 100+1=101 priority score, yay! */
  line-height: 1;
  color: inherit;
}

Fraase answered 30/12, 2014 at 11:13 Comment(9)

since IDs can only be used once, why not make #bootstrap-overrides a class? – Widera 19/8, 2015 at 3:7

@chharvey: because you would end up having to calculate better. if it were a class in this example it would be prio 11 and if the css definition would be after the bootstrap.css then we would be good to go. However this would be pretty close and setting it as an id which boosts the prio big time, we don't have to worry about calculating prio and testing as hard whether we have it always right. easier with an id if you want to definitively overwrite the default. – Zannini 11/9, 2015 at 6:15

just made my day. i know this and still get stuck trying to figure out why my styles aren't interpreted. – Zannini 11/9, 2015 at 6:17

Are the points you mentioned (100 for id's, 10 for classes/pseudo classes, 1 for tag selectors/pseudo elements) literal, or did you just make those values up for this example? – Flintlock 20/7, 2017 at 19:17

Your explanation is good, it makes sense as a way to explain it to someone new to css, but is misleading. The correct name for what you mentioned is css specificity which defines the "weight" of each css selector. Here some more details about it: css-tricks.com/specifics-on-css-specificity/… – Squarerigger 16/10, 2018 at 6:11

Would it be possible using this approach to simply add the id="bootstrap-overrides" to the <html> element thus making the whole page use custom css when available – Posturize 12/1, 2019 at 1:50

Your approach is not a good practice at all, your approach needs heavy manipulation in markup files and adding id's to every element, when it became a good practice. – Iritis 20/6, 2019 at 7:51

Excellent answer, I had 3 buttons which were reduced to 60% on screens less than 1200px. so I used #bootstrap-override-1,#bootstrap-override-2,#bootstrap-override-3 It's so rare to do this I didn't mind repeating the code and I needed to further customize #bootstrap-override-3 anyway. – Unknowing 23/11, 2020 at 22:1

@KyleVassella I looked it up because I had the same question. The values the above user mentioned for specificity (1, 10, 100) are indeed correct. See this section on W3: w3schools.com/css/…! – Acciaccatura 28/7, 2023 at 14:15

121

In the head section of your html place your custom.css below bootstrap.css.

<link href="bootstrap.min.css" rel="stylesheet">
<link href="custom.css" rel="stylesheet">

Then in custom.css you have to use the exact same selector for the element you want to override. In the case of legend it just stays legend in your custom.css because bootstrap hasn't got any selectors more specific.

legend {
  display: inline;
  width: auto;
  padding: 0;
  margin: 0;
  font-size: medium;
  line-height: normal;
  color: #000000;
  border: 0;
  border-bottom: none;
}

But in case of h1 for example you have to take care of the more specific selectors like .jumbotron h1 because

h1 {
  line-height: 2;
  color: #f00;
}

will not override

.jumbotron h1,
.jumbotron .h1 {
  line-height: 1;
  color: inherit;
}

Here is a helpfull explantion of specificity of css selectors which you need to understand to know exactly which style rules will apply to an element. http://css-tricks.com/specifics-on-css-specificity/

Everything else is just a matter of copy/paste and edit styles.

Whilom answered 21/12, 2013 at 17:4 Comment(1)

Can you show us how to do this in scss? I'm trying to override a BS class style in scss by doing this method and it doesn't work. – Clothe 17/4, 2022 at 2:32

It should not effect the load time much since you are overriding parts of the base stylesheet.

Here are some best practices I personally follow:

Always load custom CSS after the base CSS file (not responsive).
Avoid using !important if possible. That can override some important styles from the base CSS files.
Always load bootstrap-responsive.css after custom.css if you don't want to lose media queries. - MUST FOLLOW
Prefer modifying required properties (not all).

Dilute answered 21/12, 2013 at 16:54 Comment(1)

since bootstrap-responsive.css no longer exists, does this still stand true, or is this no longer relevant? – Ecclesiasticus 31/1, 2017 at 0:38

Link your custom.css file as the last entry below the bootstrap.css. Custom.css style definitions will override bootstrap.css

Html

<link href="css/bootstrap.min.css" rel="stylesheet">
<link href="css/custom.css" rel="stylesheet">

Copy all style definitions of legend in custom.css and make changes in it (like margin-bottom:5px; -- This will overrider margin-bottom:20px; )

Mur answered 21/12, 2013 at 16:50 Comment(4)

Yes, I did that already. Sorry my question wasn't clear. My question was asking what to do in custom.css to override styles from bootstrap.min.css. – Contempt 21/12, 2013 at 16:59

What if I'm also using bootstrap-theme.min.css? – Burtonburty 20/8, 2015 at 1:32

Worked for me, even with min css – Amundson 12/7, 2019 at 6:18

And what about compiling your own custom version of Bootstrap using .scss files ? (Bootstrap provides source bundle with .scss files, so you can compile the original Bootstrap css and import your custom .scss files after all the original .scss; you can override variables values as well for minor changes like theming). Indeed, the most common way for overwritting Bootstrap styles is to update Sass variables (it seems to be the recommended way). – Latoria 26/1 at 9:31

Update 2021 - Bootstrap 4 and Bootstrap 5

There are 3 rules to follow when overriding Bootstrap CSS..

import/include bootstrap.css before your CSS rules (overrides)
use more CSS Specificity (or equal) than the Bootstrap CSS selectors
if any rule is overridden, use !important attribute to force your rules. If you follow rules 1 & 2 this shouldn't be necessary except for when using Bootstrap utility classes which often contain !important as explained here

Yes, overrides should be put in a separate styles.css (or custom.css) file so that the bootstrap.css remains unmodified. This makes it easier to upgrade the Bootstrap version without impacting the overrides. The reference to the styles.css follows after the bootstrap.css for the overrides to work.

<link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="css/styles.css">

Just add whatever changes are needed in the custom CSS. For example:

legend {
  display: block;
  width: inherit;
  padding: 0;
  margin-bottom: 0;
  font-size: inherit;
  line-height: inherit;
  color: inherit;
  white-space: initial;
}

Note: It's not a good practice to use !important in the override CSS, unless you're overriding one of the Bootstrap Utility classes. CSS specificity always works for one CSS class to override another. Just make sure you use a CSS selector that is that same as, or more specific than the bootstrap.css

For example, consider the Bootstrap 4 dark Navbar link color. Here's the bootstrap.css...

.navbar-dark .navbar-nav .nav-link {
    color: rgba(255,255,255,.5);
}

So, to override the Navbar link color, you can use the same selector, or a more specific selector such as:

#mynavbar .navbar-nav .nav-link {
    color: #ffcc00;
}

For example: https://codeply.com/p/FyQapHImHg

When the CSS selectors are the same, the last one takes precedence, which it why the styles.css should follow the bootstrap.css.

Simonesimoneau answered 28/8, 2018 at 2:15 Comment(3)

This doesn't seem to say anything new; several existing answers discuss putting your styles in a new CSS file that loads after the Bootstrap CSS files. – Flinch 28/8, 2018 at 2:26

#mynavbar is the id of the nav bar :D for new comers – Mullen 9/12, 2021 at 15:11

@Mullen #mynavbar is the id of the navbar, and the parent of the navbar-nav – Simonesimoneau 9/12, 2021 at 15:41

To reset the styles defined for legend in bootstrap, you can do following in your css file:

legend {
  all: unset;
}

Ref: https://css-tricks.com/almanac/properties/a/all/

The all property in CSS resets all of the selected element's properties, except the direction and unicode-bidi properties that control text direction.

Possible values are: initial, inherit & unset.

Side note: clear property is used in relation with float (https://css-tricks.com/almanac/properties/c/clear/)

Angevin answered 28/8, 2018 at 4:57 Comment(0)

See https://bootstrap.themes.guide/how-to-customize-bootstrap.html

For simple CSS Overrides, you can add a custom.css below the bootstrap.css

<link rel="stylesheet" type="text/css" href="css/bootstrap.min.css">
<link rel="stylesheet" type="text/css" href="css/custom.css">

For more extensive changes, SASS is the recommended method.

create your own custom.scss
import Bootstrap after the changes in custom.scss

For example, let’s change the body background-color to light-gray #eeeeee, and change the blue primary contextual color to Bootstrap's $purple variable...

/* custom.scss */    

/* import the necessary Bootstrap files */
@import "bootstrap/functions";
@import "bootstrap/variables";

/* -------begin customization-------- */   

/* simply assign the value */ 
$body-bg: #eeeeee;

/* or, use an existing variable */
$theme-colors: (
  primary: $purple
);
/* -------end customization-------- */  

/* finally, import Bootstrap to set the changes! */
@import "bootstrap";

Deliladelilah answered 5/8, 2019 at 20:12 Comment(0)

A bit late but what I did is I added a class to the root div then extends every bootstrap elements in my custom stylesheet:

.overrides .list-group-item {
    border-radius: 0px;
}
.overrides .some-elements-from-bootstrap { 
    /* styles here */
}

<div class="container-fluid overrides">
    <div class="row">
        <div class="col-sm-4" style="background-color: red">
            <ul class="list-group">
                <li class="list-group-item"><a href="#">Hey</a></li>
                <li class="list-group-item"><a href="#">I was doing</a></li>
                <li class="list-group-item"><a href="#">Just fine</a></li>
                <li class="list-group-item"><a href="#">Until I met you</a></li>
                <li class="list-group-item"><a href="#">I drink too much</a></li>
                <li class="list-group-item"><a href="#">And that's an issue</a></li>
                <li class="list-group-item"><a href="#">But I'm okay</a></li>
            </ul>
        </div>
        <div class="col-sm-8" style="background-color: blue">
            right
        </div>
    </div>
</div>

Quigley answered 10/12, 2017 at 8:35 Comment(4)

Does body tag reside in div tag? – Pauwles 3/11, 2020 at 11:11

@SubratoPatnaik it should not. – Quigley 4/11, 2020 at 7:2

How can we override the css for the body element? It is good practice to use id instead of class selector? Can you help me with this? – Pauwles 4/11, 2020 at 7:20

@SubratoPatnaik Iook at the top-most answer of this question. Overriding CSS rules this way have a lesser priority over id. Maybe? Try it. – Quigley 4/11, 2020 at 7:41

If you are planning to make any rather big changes, it might be a good idea to make them directly in bootstrap itself and rebuild it. Then, you could reduce the amount of data loaded.

Please refer to Bootstrap on GitHub for the build guide.

Inverness answered 21/12, 2013 at 17:11 Comment(3)

Depending on the extent of required customization this could be the simplest option. For example, changing any theme colors would require so many overrides that I'd rather opt for a template change, and custom build. – Stelle 18/9, 2014 at 14:55

@alex Bump sources and rebuild? – Lorca 29/10, 2015 at 16:7

IMHO - My personal rule is to NEVER EVER modify the source files in CSS, JS or any other lib - In today's world there should always be a graceful workaround, otherwise you get into problems updating your sources. – Nonentity 18/8, 2020 at 14:55

I found out that (bootstrap 4) putting your own CSS behind bootstrap.css and .js is the best solution.

Find the item you want to change (inspect element) and use the exact same declaration then it will override.

It took me some little time to figure this out.

Resumption answered 25/11, 2017 at 10:21 Comment(0)

for ruby on rails users--

in your application css file, make sure the bootstrap file is mentioned first then the custom css stylesheet. This way the latter CSS code that you wrote overwrites the former. Use !important if needed as well

 *= require 'bootstrap.min'
 *= require_self
 *= require 'name_of_your_stylesheet'

Trove answered 26/5, 2022 at 3:1 Comment(0)

-2

Inspect the target button on the console.
Go to elements tab then hover over the code and be sure to find the default id or class used by the bootstrap.
Use jQuery/javascript to overwrite the style/text by calling the function.

See this example:

  $(document).ready(function(){
      $(".dropdown-toggle").css({ 
        "color": "#212529",
        "background-color": "#ffc107",
        "border-color": "#ffc107"
       });
      $(".multiselect-selected-text").text('Select Tags');
  });

Cadmann answered 3/8, 2019 at 17:48 Comment(0)

-4

Give ID to legend and apply css. Like add id hello to legend() the css is as follw:

#legend  legend {
  display: block;
  width: 100%;
  padding: 0;
  margin-bottom: 20px;
  font-size: 21px;
  line-height: inherit;
  color: #333333;
  border: 0;
  border-bottom: 1px solid #e5e5e5;
}

Thunderstruck answered 25/5, 2018 at 7:10 Comment(0)

-10

Use jquery css instead of css . . . jquery have priority than bootstrap css...

e.g

$(document).ready(function(){
        $(".mnu").css({"color" : "#CCFF00" , "font-size": "16px" , "text-decoration" : "overline"});    


);

 instead of

.mnu
{

font-family:myfnt;
font-size:20px;
color:#006699;

}

Funds answered 29/5, 2017 at 2:4 Comment(1)

HTML should be used to provide structure, CSS should be used to provide style, and Javascript (including jQuery) should only be used to provide interactivity. Using jQuery to override styles is counter to the principles of good architecture, and will be extremely confusing to anyone trying to work on the code 6 months from now. – Smoodge 15/7, 2017 at 21:44

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