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
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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>
