Not Able to Change the Color of the alert Message in javascript react

I am trying to program an alert component but I am not able to change the colour of the alert message.

It will show an alert message that dark mode is enabled when I enable it in the navbar(present at the last in the navbar component code). I am using bootstrap CSS

Alert component:

import React from "react";

export default function Alert(props) {
 const capital = (word) => {
   const lower = word.toLowerCase();

   return lower.charAt(0).toUpperCase() + lower.slice(1);
 };
 return (
   props.alert && (
     <div
       className={`alert alert-${props.alert.type} alert-dismissible fade show`}
       role="alert"
     >
       <strong>{capital(props.alert.type)}</strong>: {props.alert.msg}
     </div>
   )
 );
}

Navbar component:

import React from "react";
import PropTypes from "prop-types";
export default function Navbar(props) {
  return (
    <>
      <nav
        className={`navbar navbar-expand-lg navbar-${props.mode} bg-${props.mode}`}
      >
        <div className="container-fluid">
          <a className="navbar-brand" href="/">
            Navbar
          </a>
          <div className="collapse navbar-collapse" id="navbarSupportedContent">
            <ul className="navbar-nav me-auto mb-2 mb-lg-0">
              <li className="nav-item">
                <a className="nav-link active" aria-current="page" href="/">
                  Home
                </a>
              </li>
              <li className="nav-item">
                <a className="nav-link" href="/">
                  Link
                </a>
              </li>

              <li className="nav-item">
                <a
                  className="nav-link "
                  href="/"
                  tabIndex="-1"
                  aria-current="page"
                >
                  {props.aboutText}
                </a>
              </li>
            </ul>
            <form className="d-flex mx-2">
              <input
                className="form-control me-2"
                type="search"
                placeholder="Search"
                aria-label="Search"
              />
              <button className="btn btn-outline-success" type="submit">
                Search
              </button>
            </form>

            <div
              className={`form-check form-switch text-${
                props.mode === "light" ? "dark" : "light"
              } mx-2`}
            >
              <input
                className="form-check-input "
                onClick={props.togglemode}
                type="checkbox"
                id="flexSwitchCheckDefault"
              />
              <label
                className={`form-check-label `}
                htmlFor="flexSwitchCheckDefault"
              >
                Enable Dark Mode
              </label>
            </div>
          </div>
        </div>
      </nav>
    </>
  );
}

App.js:

import "./App.css";
import Navbar from "./components/Navbar";
import React, { useState } from "react";
import Alert from "./components/Alert";
function App() {
  const [mode, setMode] = useState("light");
  const [alert, setAlert] = useState(null);
  const showAlert = (message, type) => {
    setAlert({
      msg: message,
      type: type,
    });
    setTimeout(() => {
      setAlert(null);
    }, 1500);
  };
  const togglemode = () => {
    if (mode === "light") {
      setMode("dark");
      document.body.style.backgroundColor = "#042743";
      showAlert("Dark mode has been enabled", "Success");
    } else {
      setMode("light");
      document.body.style.backgroundColor = "white";
      showAlert("Light mode has been enabled", "Success");
    }
  };
  return (
    <>
      <Navbar aboutText="About Myself" mode={mode} togglemode={togglemode} />
      <div className="container " my-3="true">
        <Alert alert={alert} />
      </div>
    </>
  );
}

export default App;