title: Implementation of dark mode with variables in React/Sass project
body: <p>I am working on a Sass project and I am pretty new to it.</p>
  <p>I have a <code>_variables.scss</code> file which contains the variables for UI. I want to change the values of those variables <strong>dynamically</strong> (<em>not creating new ones</em>), with the use of React. How can I do so?</p>
  <p>Expected Outcome is something like:
  In scss file,
  Check if dark mode is active or not and define a set of variables.</p>
  <p>In js file,
  Change the state of light and dark mode programmatically.</p>