How to customize ‘read more’

This only makes the read more link a button.

add_filter( 'excerpt_more', 'wpsites_read_more_link' );
    function wpsites_read_more_link( $more ) {
        return '... <a class="more-link button" href="' . get_permalink() . '">Continue Reading</a>';
}

Replace the button class with your themes button class.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)