R (red), G (green), B (blue), and A (alpha) are hexadecimal characters (0–9, A–F). In browsers that implement the Level 4 standard, they accept the same parameters and behave the same way. Note: As of CSS Colors Level 4, rgba() is an alias for rgb().
![color 255 255 255 color 255 255 255](http://cdn-0.access-excel.tips/wp-content/uploads/2015/02/rgb-color.jpg)
The color keywords all represent plain, solid colors, without transparency.Unlike HTML, CSS will completely ignore unknown keywords.The other color keywords should only be used in CSS and SVG.
![color 255 255 255 color 255 255 255](https://cuongquoc.com.vn/media/product/10296_gach_inax_pastel_plain_color_255_ppc_209.jpg)
![color 255 255 255 color 255 255 255](https://d33v4339jhl8k0.cloudfront.net/docs/assets/56d89d3a9033600eafd436e0/images/585884eec697912ffd6c31e3/file-CeSz5qtQvk.png)
HTML only recognizes the 16 basic color keywords found in CSS1, using a specific algorithm to convert unrecognized values (often to completely different colors).There are a few caveats to consider when using color keywords: Although the names more or less describes their respective colors, they are essentially artificial, without a strict rationale behind the names used. Color keywords are case-insensitive identifiers that represent a specific color, such as red, blue, black, or lightseagreen.