Hello,
As you can see the button “Back to top” uses background image (wp-content/themes/crown_jules_diamonds.co.uk/images/top.png). You need to edit this image if you want to change its color.
To change selection color use this css code in custom.css:
::selection {
background-color: #008000;
}
Set the value to yours.
To create custom.css you need rename default.custom.css to custom.css in wp-content/themes/blanco directory via FTP and enable it in Blanco – Theme Settings, tick “Enable Custom CSS file”.
Best regards,
Jack Richardson.