* Tweak green and cyan colors, bump min contrast ratio to 4.5

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

Replaces #30498 by adding four new null default variables for .nav-link. Doesn't carry over font-style from the original PR though since that's rarely used, at least by default Bootstrap. Nullifies all values from that PR, too, since we count on some basic inheritance here and don't need color by default.

currently, `$gray-200` is practically imperceptible. switch to reusing `$dropdown-border-color`.

Inherit `font-weight: bold` that comes from user agent stylesheets.

* v5: Redo blockquote attributions

- Renames -small-* variables to -footer-*
- Updates blockquote demos with attribution to place it outside the blockquote with a figure wrapper

* Updated class name

* docs(examples): refactor blockquotes in masonry example

Co-authored-by: Gaël Poupard <gael.poupard@orange.com>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>

- Use a semitransparent gradient from light to dark which works on any background-color
- Store the gradient as a custom property (--bs-gradient)
- Remove `.bg-gradient-*` variants in favour of `.bg-gradient` which works even when `$enable-gradients` are enabled
- Add gradients to navbar, active page links and badges when gradients are enabled

Replaces a custom hsla() value (dunno what I was thinking when I added this) with a reassigned existing variable. This variable goes up the stack and attaches to the component-active-bg variable, derived from our primary color out of the box. Fixes #30646.

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

- Rename `$enable-prefers-reduced-motion-media-query` to `$enable-reduced-motion`
- Rename `$enable-pointer-cursor-for-buttons` to `$enable-button-pointers`

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

* Disable negative margins by default

* Use shorter enable variable

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

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

- Define background properties in `.form-check-input`
- Use `background-size: contain` to simplify background sizes (especially for those with linear gradients)
- Remove double `color-adjust`
- Adjust svgs to 20x20 box. This way the strokes aren't rescaled.

- Convert to Sass map
- Consolidate font-weights into single option (matching line-height for them)
- Add two new sizes and create a new scale
- Update migration docs

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

- Updates mentions of number and exact tiers
- Updates grid example to include xxl container
- Adds some scss-docs references
- Cleans up other grid mentions and docs
- Updates navbar example to include an expand at XXL variant

- Staring at my laptop, I realized I'm wasting away space. This adds a 
significant amount of CSS, but it feels right already.
- Added the xxl tier with a width that divides by 12
- Motivation was originally trying to have a third column for our toc so 
that our docs are more useful

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

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

Co-authored-by: David Van Doninck <david.vandoninck@intracto.com>
Co-authored-by: XhmikosR <xhmikosr@gmail.com>
Co-authored-by: Martijn Cuppens <martijn.cuppens@gmail.com>

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

Fixes beeing able to control `.is-valid` & `.is-invalid` input:focus opacity