Issue number: resolves#24638, resolves#18592
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issue. -->
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## What is the current behavior?
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Developers have requested that Ionic Framework support the dynamic type
feature on iOS for accessibility purposes. Ionic applications do not
respond to font scaling on iOS which can create inaccessible
applications particularly for users with low vision. Ionic apps on
Android devices currently support the Android equivalent due to
functionality in the Chromium webview.
Developers have also requested a way of adjusting the fonts in their
Ionic UI components consistently.
## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->
- Ionic components now use `rem` instead of `px` where appropriate. This
means devs can change the font size on `html` and the text in supported
Ionic components will scale up/down appropriately
- Add support for Dynamic Type on iOS (the iOS version of Dynamic Font
Scaling)
## Does this introduce a breaking change?
- [ ] Yes
- [x] No
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and migration path for existing applications below. -->
## Other information
<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->
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Co-authored-by: Maria Hutt <thetaPC@users.noreply.github.com>
Co-authored-by: Brandy Carney <brandyscarney@users.noreply.github.com>
Co-authored-by: Shawn Taylor <shawn@ionic.io>
Co-authored-by: ionitron <hi@ionicframework.com>
Co-authored-by: Sean Perkins <sean@ionic.io>
Co-authored-by: Sean Perkins <13732623+sean-perkins@users.noreply.github.com>
Co-authored-by: Amanda Johnston <90629384+amandaejohnston@users.noreply.github.com>
Updates all of the global variables to make sure their naming is consistent, their default values are correct, they are used properly by the related components, and remove any that are not used.
- removes some of the non mode-specific global Sass variables
- updates the md and ios values so that the default is the css variable
with different fallbacks
- removes non-color related css variables from the global file
- fixes item so it uses the background color that is set by the global
file
# Breaking Changes
## Removed Global CSS Variables
The following global CSS variables have been removed for the reasons listed.
| Variable Name | Reason |
| ----------------------------------| ------------------------------------------------|
| `--ion-toolbar-color-inactive` | Unused |
| `--ion-ripple-background-color` | Unused / Ripple color is based on component |
| `--ion-header-size` | Removed in favor of using CSS for h1-h6 |
| `--ion-header-step` | Removed in favor of using CSS for h1-h6 |
## Renamed Global CSS Variables
The following global CSS variables have been renamed for the reasons listed.
| Old Variable Name | New Variable Name | Reason |
| -----------------------------------------| -----------------------------------| ------------------------------------------------------------------------------|
| `--ion-toolbar-text-color` | `--ion-toolbar-color` | Variable is not limited to text color |
| `--ion-toolbar-color-active` | `--ion-toolbar-color-activated` | Consistency with our component variables |
| `--ion-tabbar-text-color` | `--ion-tab-bar-color` | Variable is not limited to text color |
| `--ion-tabbar-text-color-active` | `--ion-tab-bar-color-activated` | Consistency with our component variables |
| `--ion-tabbar-background-color` | `--ion-tab-bar-background` | Applies to the background property |
| `--ion-tabbar-background-color-focused` | `--ion-tab-bar-background-focused` | Applies to the background property |
| `--ion-item-background-color` | `--ion-item-background` | Applies to the background property |
| `--ion-item-background-color-active` | `--ion-item-background-activated` | Applies to the background property / Consistency with our component variables |
| `--ion-item-text-color` | `--ion-item-color` | Variable is not limited to text color |
| `--ion-placeholder-text-color` | `--ion-placeholder-color` | Consistency with other variables |
Fixes#15989Fixes#15559
