docs(slides): document css vars (#19872)

Author: brandyscarney

core/api.txt

@@ -1091,6 +1091,10 @@ ion-slides,event,ionSlideTransitionStart,void,true
 ion-slides,event,ionSlideWillChange,void,true
 ion-slides,css-prop,--bullet-background
 ion-slides,css-prop,--bullet-background-active
+ion-slides,css-prop,--progress-bar-background
+ion-slides,css-prop,--progress-bar-background-active
+ion-slides,css-prop,--scroll-bar-background
+ion-slides,css-prop,--scroll-bar-background-active
 
 ion-spinner,shadow
 ion-spinner,prop,color,string | undefined,undefined,false,false

core/src/components/slides/readme.md

@@ -761,10 +761,14 @@ Type: `Promise<void>`
 
 ## CSS Custom Properties
 
-| Name                         | Description                                |
-| ---------------------------- | ------------------------------------------ |
-| `--bullet-background`        | Background of the pagination bullets       |
-| `--bullet-background-active` | Background of the active pagination bullet |
+| Name                               | Description                                      |
+| ---------------------------------- | ------------------------------------------------ |
+| `--bullet-background`              | Background of the pagination bullets             |
+| `--bullet-background-active`       | Background of the active pagination bullet       |
+| `--progress-bar-background`        | Background of the pagination progress-bar        |
+| `--progress-bar-background-active` | Background of the active pagination progress-bar |
+| `--scroll-bar-background`          | Background of the pagination scroll-bar          |
+| `--scroll-bar-background-active`   | Background of the active pagination scroll-bar   |
 
 
 ----------------------------------------------

core/src/components/slides/slides.scss

@@ -8,6 +8,12 @@ ion-slides {
   /**
    * @prop --bullet-background: Background of the pagination bullets
    * @prop --bullet-background-active: Background of the active pagination bullet
+   *
+   * @prop --progress-bar-background: Background of the pagination progress-bar
+   * @prop --progress-bar-background-active: Background of the active pagination progress-bar
+   *
+   * @prop --scroll-bar-background: Background of the pagination scroll-bar
+   * @prop --scroll-bar-background-active: Background of the active pagination scroll-bar
    */
   display: block;