React.js: How to override css property?

I have a footer in which its margin-left should adjust whenever I click the minimize sidebar menu. The margin-left property is declare on CSS as 270px, however, when the sidebar is closed I want to margin-left property in CSS to be set at 90px.

I can get the value if the sidebar is opened or closed (true or false), on my footer component. See code below:

Footer.js

import React from "react";
import logo from "../../images/test-logo-footer.png";
import { MDBFooter } from "mdbreact";
import { useLayoutState } from "../../context/LayoutContext";

const Footer = () => {
  var { isSidebarOpened } = useLayoutState();

  return (
    <MDBFooter color="grey" className="text-center font-small lighten-5">
      {console.log("isSidebarOpened ", isSidebarOpened)}
      {isSidebarOpened && (
        <p className="footer-copyright mb-0 p-0 py-1 text-center">
          {
            <a href="#!" className="logo-wrapper waves-effect">
              <img alt="" className="img-fluid" src={logo} />
            </a>
          }
        </p>
      )}
    </MDBFooter>
  );
};

export default Footer;

As you can see above, the isSidebarOpened variable is true when sidebar is opened, false when closed.

CSS code below:

body {
  margin: 0;
  /* font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol"; */
  font-size: 1rem;
  font-weight: 400;
  line-height: 1.5;
  color: #212529;
  text-align: left;
  background-color: #ededee;
}

a {
  color: inherit;
}

.list-group-flush {
  color: #495057;
}

.active {
  background-color: #e9ecef !;
}

main {
  background-color: #ededee;
}

.navbar-brand {
  margin-left: 15px;
  color: #2196f3 !important;
}

.flexible-navbar {
  transition: padding-left 0.5s;
  padding-left: 270px;
  background: #fff;
}

#content {
  margin-left: 270px;
  /* height: 80%; TO:DO - to change after testing responsiveness */
}

.sidebar-fixed {
  left: 0;
  top: 0;
  height: 100vh;
  width: 270px;
  box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.16), 0 2px 10px 0 rgba(0, 0, 0, 0.12);
  z-index: 1050;
  background-color: #fff;
  padding: 0rem 1rem 0rem 1rem;
}

.sidebar-fixed .logo-wrapper img {
  width: 100%;
  padding-top: 0rem;
  padding-left: 1rem;
  padding-right: 1rem;
  padding-bottom: 0rem;
}

.list-group-item-header {
  display: block !important;
  transition: background-color 0.3s;
  overflow: hidden;
  position: relative;
  border: none;
}

.list-group-item {
  display: block !important;
  transition: background-color 0.3s;
  overflow: hidden;
  position: relative;
  border: none;
}

.child-list-item {
  font-size: 13px;
  padding-left: 3em;
}

.list-group-item-header:hover {
  color: #49505b;
  text-decoration: none;
  background-color: none;
}

.list-group-item-header:hover {
  color: #49505b;
  text-decoration: none;
  background-color: none;
}

.list-group-item:hover {
  color: #49505b;
  text-decoration: none;
  background-color: #f8f9fa;
}

.list-group-item:hover {
  color: #49505b;
  text-decoration: none;
  background-color: #f8f9fa;
}

.list-group .active {
  box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.16), 0 2px 10px 0 rgba(0, 0, 0, 0.12);
  border-radius: 5px;
}

.card-title {
  font-size: 1.5rem;
  font-weight: 600;
}

.card-subtitle {
  font-size: 1.25rem;
  font-weight: 600;
}

.full {
  height: 70vh;
}

.bad-gateway-row {
  margin: 0;
  position: absolute;
  top: 50%;
  left: 55%;
  -webkit-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}

.card .view.gradient-card-header {
  padding: 1rem 1rem;
  text-align: center;
}

.card h3,
.card.card-cascade h4 {
  margin-bottom: 0px;
}

.cascading-admin-card .admin-up {
  margin-left: 4%;
  margin-right: 4%;
  margin-top: -20px;
}

.cascading-admin-card .admin-up .fa {
  box-shadow: 0 2px 9px 0 rgba(0, 0, 0, 0.2), 0 2px 13px 0 rgba(0, 0, 0, 0.19);
}

.cascading-admin-card .admin-up .fa {
  padding: 1.7rem;
  font-size: 2rem;
  color: #fff;
  text-align: left;
  margin-right: 1rem;
  border-radius: 3px;
}

.cascading-admin-card .admin-up .data {
  float: right;
  margin-top: 2rem;
  text-align: right;
}
.admin-up .data p {
  color: #999999;
  font-size: 12px;
}
.classic-admin-card .card-body {
  color: #fff;
  margin-bottom: 0;
  padding: 0.9rem;
}
.classic-admin-card .card-body p {
  font-size: 13px;
  opacity: 0.7;
  margin-bottom: 0;
}
.classic-admin-card .card-body h4 {
  margin-top: 10px;
}

.form-inline {
  flex-flow: unset;
}

.breadcrumb {
  margin: 0;
  /* tentative font size  */
  font-size: 1rem;
}

.activeClass .list-group-item {
  z-index: 5;
  color: #fff;
  border-color: #007bff;
  box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.16), 0 2px 10px 0 rgba(0, 0, 0, 0.12);
  border-radius: 5px !important;
  background-color: #007bff !important;
}

.activeClassItem .list-group-item {
  z-index: 5;
  color: #fff;
  border-color: #007bff;
  box-shadow: 0 2px 5px 0 rgba(0, 0, 0, 0.16), 0 2px 10px 0 rgba(0, 0, 0, 0.12);
  border-radius: 5px !important;
  background-color: #007bff !important;
}

.page-footer {
  margin-left: 270px;
  /* margin-left: 90px; */
}

In the last part of CSS which is .page-footer, this is where the margin for the footer comes from. However, I'm not sure how does my footer page calls the CSS property, therefore, I don't know how to toggle it depending on the sidebar.

TIA