Changing the look of a navigation menu button

My website is:

I’d like to make that button “Kontakt” has white text and a purple background, like this or maybe purple text surrounded by a pill shape, like this.

Is it possible to do it with CSS or do I need to download some plugin?

I downloaded MaxButtons and made a button as I desired. It gave me a shortcode [maxbutton id=“1”] but I don’t know where to put it to change the look of the button.

Hello there,

I hope you are doing well today.

You can use the following CSS code to change the button colors by going to Appearance > Customize > Additional CSS and pasting it there.

/*Button appearance*/
.btn, .button {
    font-family: "Raleway", "Helvetica Neue", Helvetica, Arial, sans-serif;
    border: 2px solid #745cf9;
    font-size: 12px;
    border-radius: 10px;
    color: #745cf9;

.btn-filled {
    background: #fff;
    color: #745cf9;

Best Regards,