* Add additional root variables, rename $variable-prefix to $prefix

- Adds new root CSS variables for border-radius, border-width, border-color, and border-style
- Adds new root CSS variables for heading-color, link-colors, code color, and highlight color
- Replaces most instances of Sass variables (for border-radius, border-color, border-style, and border-width) for CSS variables inside _variables.scss
- Updates $mark-padding to be an even pixel number
- Renames $variable-prefix to $prefix throughout

* Bundlewatch

- Adds new functions to generate additional Sass maps
- Adds new root variables for rgb() versions of our theme colors, plus a few extras
- Adds ability to change the alpha transparency of text color and background color utilities with new utilities, inline styles, or local CSS var
- Updates documentation for color and background-color utilities pages
- Deprecates .text-black-50 and .text-white-50 since those (and additional transparency levels) can be generated on the fly

Change approach slightly to prevent cascade

* Add maps for all colors, document how to extend color utilities

* Updates to make this more functional for v5

- Moves color maps into _variables.scss for now (felt weird to split them out when the variables are there)
- Adds a new function, map-merge-multiple(), and updates docs that reference combo-map
- Updates code snippet and docs guidance about how to extend the color utils to handle this

* Update site/content/docs/5.0/customize/color.md

Co-authored-by: Gaël Poupard <ffoodd@users.noreply.github.com>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>

* Convert bulk of division to multiplication

* Use custom divide() function instead of Dart Sass math module for greater compatibility

* Apply suggestions from code review

* Fix functions

Rename scale-color() function to shift-color() to avoid collision with Sass's own color function (#32149)

 Closes #30835 by leaving a comment in the source that the escape-svg() function must have quotes around data URIs.

feat(color-contrast): ensure we return a contrasted enough color (light-first), the most contrasted one otherwise

Co-authored-by: Martijn Cuppens <martijn.cuppens@gmail.com>

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

Co-authored-by: XhmikosR <xhmikosr@gmail.com>

* Add variables for shades and tints of each major color

* getting-started/theming.md: use a `range`.

Drop `color()`, `theme-color()` & `gray()` functions  in favor of variables. The functions just called a `map-get()` of a map where just the variables were defined. 

Also the `theme-color-level()` now accepts any color you want instead of only `$theme-colors` colors. The first value now is a variable instead of the `$theme-colors` key.

* Use escape-svg() function

* Update theming.md

Co-Authored-By: Martijn Cuppens <martijn.cuppens@gmail.com>

* Add map-name param to _assert-starts-at-zero

* Set default value for backwards compatibility

Closes #25313