319

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;
}
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1
  • Just make sure your own css loads after the bootstrap css.
    – José Rasmussen
    Commented Sep 12, 2022 at 20:18

15 Answers 15

Reset to default
614

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;
}
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9
  • 1
    since IDs can only be used once, why not make #bootstrap-overrides a class?
    – chharvey
    Commented Aug 19, 2015 at 3:07
  • 4
    @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.
    – hogan
    Commented Sep 11, 2015 at 6:15
  • 7
    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?
    – Kyle Vassella
    Commented Jul 20, 2017 at 19:17
  • 3
    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/…
    – Adriano
    Commented Oct 16, 2018 at 6:11
  • 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/…!
    – Omar Shishani
    Commented Jul 28, 2023 at 14:15
122

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.

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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.
    – KYin
    Commented Apr 17, 2022 at 2:32
31

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:

  1. Always load custom CSS after the base CSS file (not responsive).
  2. Avoid using !important if possible. That can override some important styles from the base CSS files.
  3. Always load bootstrap-responsive.css after custom.css if you don't want to lose media queries. - MUST FOLLOW
  4. Prefer modifying required properties (not all).
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1
  • 14
    since bootstrap-responsive.css no longer exists, does this still stand true, or is this no longer relevant?
    – wilson0x4d
    Commented Jan 31, 2017 at 0:38
29

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; )

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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.
    – Alex
    Commented Dec 21, 2013 at 16:59
  • What if I'm also using bootstrap-theme.min.css?
    – Quasaur
    Commented Aug 20, 2015 at 1:32
  • Worked for me, even with min css
    – mimi
    Commented Jul 12, 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).
    – Ishikawa
    Commented Jan 26 at 9:31
13

Update 2021 - Bootstrap 4 and Bootstrap 5

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

  1. import/include bootstrap.css before your CSS rules (overrides)
  2. use more CSS Specificity (or equal) than the Bootstrap CSS selectors
  3. 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.

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3
  • 1
    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.
    – TylerH
    Commented Aug 28, 2018 at 2:26
  • #mynavbar is the id of the nav bar :D for new comers
    – Zunair
    Commented Dec 9, 2021 at 15:11
  • @Zunair #mynavbar is the id of the navbar, and the parent of the navbar-nav
    – Carol Skelly
    Commented Dec 9, 2021 at 15:41
9

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/)

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7

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

  1. 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">

  2. 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";
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0
4

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>
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4
  • Does body tag reside in div tag?
    – Subrato Pattanaik
    Commented Nov 3, 2020 at 11:11
  • @SubratoPatnaik it should not.
    – mr5
    Commented Nov 4, 2020 at 7:02
  • 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?
    – Subrato Pattanaik
    Commented Nov 4, 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.
    – mr5
    Commented Nov 4, 2020 at 7:41
3

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.

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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.
    – David Kirkland
    Commented Sep 18, 2014 at 14:55
  • @alex Bump sources and rebuild?
    – Victor Häggqvist
    Commented Oct 29, 2015 at 16:07
  • 2
    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.
    – G-Man
    Commented Aug 18, 2020 at 14:55
1

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.

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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'
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0

I did the solution to define local css class. For instance I was using bootstrap navigation class like this -

<div className="collapse navbar-collapse menu-align" id="navbarNavAltMarkup">
  <div className="navbar-nav">
      <a className="nav-link active" aria-current="page" href="#">Home</a>
      <a className="nav-link" href="#">Login</a>
      <a className="nav-link" href="#">Sign-up</a>
  </div>
</div>

Here bootstrap class "navbar-collapse" and the property of this css class as below -

navbar-collapse {
  flex-basis: 100%;
  flex-grow: 1;
  align-items: center;
}

And want to remove/or alter flex-grow value, to solve this added a custom class like menu-align

menu-align {
  flex-grow: 0
}

and added this class after bootstrap class. finally this work for me.

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-2
  1. Inspect the target button on the console.
  2. Go to elements tab then hover over the code and be sure to find the default id or class used by the bootstrap.
  3. 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');
  });
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-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;
}
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-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;

}
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1
  • 7
    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.
    – Stephen R. Smith
    Commented Jul 15, 2017 at 21:44

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