added toggle button to index.html

Author: SuhainaFathimaM

Website/index.html

@@ -26,6 +26,11 @@
                         <img src="https://github.githubassets.com/images/modules/logos_page/GitHub-Mark.png" alt="GitHub" width="25" height="25"> <!-- GitHub Icon -->
                     </a>
                 </li>
+                <li>
+                    <button id="toggle-dark-mode">
+                        <i class="fas fa-moon"></i> 
+                    </button>
+                </li>
             </ul>
         </nav>
     </header>