You can customize the info window with infowindow width, border color, border-radius, background color. In this tutorial, we’ll help you how to customize or change the color of the infowindow.
Customize infowindow in a Leaflet map

Step 1 Go to Manage Map -> Edit Page.

Step 2: Scroll down to ‘Infowindow Customization Settings’ section and enable ‘Turn On Infowindow Customization’ checkbox.

Step 3: Configure the infowindow height, Border Color , Border Radius , Background Color.

Step 4: Then click Save Map. Now you’ll see infowindow color display according to your customization.