fix(checkbox): improve states and colors (#30559)

Issue number: internal

---------

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issue. -->

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## What is the new behavior?
<!-- Please describe the behavior or changes that are being added by
this PR. -->

- update scss to use vars;
- add more examples to states page;
- now the invalid state is only possible for unchecked checkboxes;

## Does this introduce a breaking change?

- [ ] Yes
- [x] No

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  2. Update the BREAKING.md file with the breaking change.
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## Other information

<!-- Any other information that is important to this PR such as
screenshots of how the component looks before and after the change. -->

[basic](https://ionic-framework-git-rou-12073-ionic1.vercel.app/src/components/checkbox/test/basic?ionic:theme=ionic)

[indeterminate](https://ionic-framework-git-rou-12073-ionic1.vercel.app/src/components/checkbox/test/indeterminate?ionic:theme=ionic)
[Bottom
Content](https://ionic-framework-git-rou-12073-ionic1.vercel.app/src/components/checkbox/test/bottom-content?ionic:theme=ionic)

[States](https://ionic-framework-git-rou-12073-ionic1.vercel.app/src/components/checkbox/test/states?ionic:theme=ionic)

---------

Co-authored-by: ionitron <[email protected]>

Author: JoaoFerreira-FrontEnd

core/src/components/checkbox/checkbox.ionic.scss

@@ -27,7 +27,8 @@
 
   // Size
   --size: #{globals.$ion-scale-600};
-  --checkbox-background-checked: #{globals.$ion-semantics-primary-base};
+  --checkbox-background: #{globals.$ion-bg-input-default};
+  --checkbox-background-checked: #{globals.$ion-bg-primary-base-default};
   --border-color-checked: #{globals.$ion-semantics-primary-base};
   --checkmark-color: #{globals.$ion-primitives-base-white};
   --transition: none;
@@ -120,7 +121,7 @@ input {
 }
 
 .checkbox-bottom .helper-text {
-  color: globals.$ion-primitives-neutral-800;
+  color: globals.$ion-text-subtlest;
 }
 
 // Label Placement - Start
@@ -187,7 +188,6 @@ input {
 
 // Checked / Indeterminate Checkbox
 // ---------------------------------------------
-
 :host(.checkbox-checked) .native-wrapper,
 :host(.checkbox-indeterminate) .native-wrapper {
   border-color: var(--border-color-checked);
@@ -199,9 +199,12 @@ input {
 // --------------------------------------------------
 :host(.ion-invalid) {
   --focus-ring-color: #{globals.$ion-border-focus-error};
+}
 
+:host(.ion-invalid:not(.checkbox-checked)),
+:host(.ion-invalid:not(.checkbox-checked).checkbox-disabled) {
   .native-wrapper {
-    border-color: globals.$ion-semantics-danger-800;
+    border-color: globals.$ion-border-danger-default;
   }
 }
 
@@ -222,7 +225,7 @@ input {
 :host(.checkbox-disabled.checkbox-checked) .native-wrapper {
   border-width: globals.$ion-border-size-0;
 
-  background-color: globals.$ion-semantics-primary-base;
+  background-color: globals.$ion-bg-primary-base-default;
 }
 
 // Checkbox Hover
@@ -233,7 +236,9 @@ input {
   }
 
   :host(:hover.checkbox-checked) .native-wrapper,
-  :host(:hover.checkbox-indeterminate) .native-wrapper {
+  :host(:hover.checkbox-checked) .checkbox-icon,
+  :host(:hover.checkbox-indeterminate) .native-wrapper,
+  :host(:hover.checkbox-indeterminate) .checkbox-icon {
     background-color: globals.$ion-semantics-primary-800;
   }
 }
@@ -248,12 +253,22 @@ input {
 // Checkbox: Active
 // --------------------------------------------------------
 :host(.ion-activated) .native-wrapper {
-  background-color: globals.$ion-primitives-neutral-200;
+  background-color: globals.$ion-bg-input-press;
 }
 
 :host(.ion-activated.checkbox-checked) .native-wrapper,
-:host(.ion-activated.checkbox-indeterminate) .native-wrapper {
-  background-color: globals.$ion-semantics-primary-900;
+:host(.ion-activated.checkbox-checked) .checkbox-icon,
+:host(.ion-activated.checkbox-indeterminate) .native-wrapper,
+:host(.ion-activated.checkbox-indeterminate) .checkbox-icon {
+  background-color: globals.$ion-bg-primary-base-press;
+}
+
+:host(.ion-activated.ion-invalid:not(.checkbox-checked)) {
+  background-color: globals.$ion-bg-input-press;
+
+  .native-wrapper {
+    border-color: globals.$ion-border-danger-press;
+  }
 }
 
 // Ionic Design Checkbox Shapes

core/src/components/checkbox/test/states/checkbox.e2e.ts

@@ -15,6 +15,18 @@ configs({ modes: ['ios', 'md', 'ionic-md'], directions: ['ltr'] }).forEach(({ ti
       await expect(checkbox).toHaveScreenshot(screenshot(`checkbox-disabled`));
     });
 
+    test('should render disabled invalid checkbox correctly', async ({ page }) => {
+      await page.setContent(
+        `
+          <ion-checkbox disabled="true" error-text="Error text" class="ion-invalid">Label</ion-checkbox>
+      `,
+        config
+      );
+
+      const checkbox = page.locator('ion-checkbox');
+      await expect(checkbox).toHaveScreenshot(screenshot(`invalid-checkbox-disabled`));
+    });
+
     test('should render disabled checked checkbox correctly', async ({ page }) => {
       await page.setContent(
         `
@@ -57,6 +69,7 @@ configs({ modes: ['ios', 'md', 'ionic-md'], directions: ['ltr'] }).forEach(({ ti
           <div id="checkboxes" style="padding: 8px">
             <ion-checkbox class="ion-focused">Label</ion-checkbox>
             <ion-checkbox class="ion-focused" checked>Label</ion-checkbox>
+            <ion-checkbox class="ion-invalid ion-focused">Label</ion-checkbox>
           </div>
       `,
         config