How can I override Bootstrap CSS styles?

Question

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;
}

Answer 1

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.

Answer 2

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.

Answer 3

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'

Answer 4

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.

Answer 5

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.

Answer 6

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');
  });

Answer 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";
     

Answer 8

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;
}

Answer 9

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.

Answer 10

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/)

Answer 11

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>

Answer 12

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).

Answer 13

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;
}

Answer 14

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;

}

Answer 15

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; )