https://www.w3schools.com/css/css_background_image.asp
https://www.w3schools.com/css/css_background.asp
No-Library (pure JS), HTML, CSS, JavaScript
https://www.w3schools.com/css/css_colors_hsl.asp
https://www.w3schools.com/css/css_colors_hex.asp
https://www.w3schools.com/css/css_colors_rgb.asp
https://www.w3schools.com/css/css_colors.asp