HTML: Includes a link to the external CSS file styles.css and the JavaScript file script.js.
CSS:
Adds basic styling to the button (padding, font-size, color, background-color, border, border-radius, cursor, and transition for smooth color change).
The button:hover selector changes the background color to red when the mouse hovers over the button.
JavaScript:
Adds an event listener for the mouseover event to change the background color to red when the mouse is over the button.
Adds an event listener for the mouseout event to change the background color back to blue when the mouse leaves the button.