'How to override styles from another css file

I have a css file (main.css) and I'd like to override it using another css file (overrides.css). But I have problem doing it as they are in different files and they get different hashes.

This is my css:

/* main.css */
.mainContainer {
    padding: 16px;
    margin: 16px;
    background-color: palevioletred;
    border-radius: 5px;
}

.mainContainer h1{
    color: white;
}


/* overrides.css */
.mainContainer h1{
    color: blue;
}

From here, I used Object.assign() to combine css files but it didn't help. This is my component:

import React from 'react';
import Main from './main.css';
import Overrides from './overrides.css';
const Style = Object.assign({}, Overrides, Main);

class Sample extends React.Component{
  render(){
    return (
      <div className={Style.mainContainer}>
        <h1>Hello</h1>
        <p>Hello CSS modules!</p>
      </div>
    );
  }
}

export default Sample;

I expect my h1 to become blue but it won't. This is my compiled css:

/* main.css */
._1pXpG {
    padding: 16px;
    margin: 16px;
    background-color: palevioletred;
    border-radius: 5px;
}
._1pXpG h1{
    color: white;
}


/* overrides.css */
.Wmy0p h1{
  color: blue;
}

I expect .Wmy0p h1 to be ._1pXpG h1 so it can override. But it won't. Note that if you just paste the content of overrides.css at the bottom of the main css it will work but I need my override css file to be in a separate file.

Thanks in advance

cssreactjscss-modulesreact-css-modules


Solution 1:[1]

To over ride styles from other file can be made by giving one more specificity from parent div. Mostly specificity solves to override other files CSS. 

class Sample extends React.Component{
render(){
    return (
      <div className={Style.mainContainerDetails}>
        <div className={Style.mainContainer}>
          <h1>Hello</h1>
          <p>Hello CSS modules!</p>
        </div>
      </div>
    );
  }
}


/* main.css */
.mainContainer {
    padding: 16px;
    margin: 16px;
    background-color: palevioletred;
    border-radius: 5px;
}

.mainContainer h1{
    color: white;
}


/* overrides.css */
.mainContainerDetails .mainContainer h1{
    color: blue;
}

Solution 2:[2]

You can just use vanilla JavaScript to replace that specific css link on the webpage. I also suggest using an event listener to wait until the page is loaded & then make the replacement.

Here is an example:

function overrideCommonCss() {
    var webpageCurrentLink = "main.css", webpageNewLink = "overrides.css", webpageFoundLink, webpageCssTags = 0,webpageAllCssLinks = document.getElementsByTagName("LINK");
    if (webpageAllCssLinks) {
        for (webpageCssTags = 0;webpageCssTags < webpageAllCssLinks.length;webpageCssTags++) {
            webpageFoundLink = webpageAllCssLinks[webpageCssTags].href;                                 
            if (webpageFoundLink.indexOf(webpageCurrentLink) !== -1) {
                webpageAllCssLinks[webpageCssTags].href = webpageAllCssLinks[webpageCssTags].href.replace(webpageCurrentLink, webpageNewLink);                  
                break;
            }                       
        }
    }
}
if(window.attachEvent) {
    window.attachEvent("onload", overrideCommonCss);            
}
else {
    window.addEventListener("load", overrideCommonCss, false);          
}

Solution 3:[3]

have you tried using the !important in css? I believe that seems to be the problem. Below is an example, in plain html:

/* main.css */
.mainContainer {
    padding: 16px;
    margin: 16px;
    background-color: palevioletred;
    border-radius: 5px;
}

.mainContainer h1{
    color: white;
}


/* overrides.css */
.mainContainer h1{
    color: blue;
}
<div class="mainContainer">
<h1>Hello World!</h1>
</div>

As you can see, using !important works pretty well for me...

Sources

This article follows the attribution requirements of Stack Overflow and is licensed under CC BY-SA 3.0.

Source: Stack Overflow

Solution Source
Solution 1 Ajay.k
Solution 2 user3447836
Solution 3 Lethal Code

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