refactor(split-button): simplify styles (#9326)

**Related Issue:** N/A

## Summary

✨🧹✨

---------

Co-authored-by: Jose Carcamo <jcarcamo@esri.com>
Co-authored-by: Jose Carcamo <138070439+josercarcamo@users.noreply.github.com>

packages/calcite-components/src/components/split-button/split-button.scss

@@ -14,52 +14,45 @@
   @apply w-full;
 }
 
-:host {
-  &:host([kind="brand"]) {
-    --calcite-split-button-background: theme("colors.brand");
-    --calcite-split-button-divider: theme("colors.background.foreground.1");
-  }
-  &:host([kind="danger"]) {
-    --calcite-split-button-background: theme("colors.danger");
-    --calcite-split-button-divider: theme("colors.background.foreground.1");
-  }
-  &:host([kind="neutral"]) {
-    --calcite-split-button-background: theme("colors.background.foreground.3");
-    --calcite-split-button-divider: theme("colors.color.1");
-  }
-  &:host([kind="inverse"]) {
-    --calcite-split-button-background: var(--calcite-color-inverse);
-    --calcite-split-button-divider: theme("colors.background.foreground.1");
-  }
+:host([kind="brand"]) {
+  --calcite-split-button-background: theme("colors.brand");
+  --calcite-split-button-divider: theme("colors.background.foreground.1");
+}
+
+:host([kind="danger"]) {
+  --calcite-split-button-background: theme("colors.danger");
+  --calcite-split-button-divider: theme("colors.background.foreground.1");
+}
+
+:host([kind="neutral"]) {
+  --calcite-split-button-background: theme("colors.background.foreground.3");
+  --calcite-split-button-divider: theme("colors.color.1");
+}
+
+:host([kind="inverse"]) {
+  --calcite-split-button-background: var(--calcite-color-inverse);
+  --calcite-split-button-divider: theme("colors.background.foreground.1");
 }
 
 :host([appearance="transparent"]) {
+  --calcite-split-button-background: transparent;
   &:host([kind="brand"]) {
     --calcite-split-button-divider: theme("colors.brand");
-    --calcite-split-button-background: transparent;
   }
   &:host([kind="danger"]) {
     --calcite-split-button-divider: theme("colors.danger");
-    --calcite-split-button-background: transparent;
   }
   &:host([kind="neutral"]) {
     --calcite-split-button-divider: theme("colors.color.1");
-    --calcite-split-button-background: transparent;
   }
   &:host([kind="inverse"]) {
     --calcite-split-button-divider: theme("colors.background.foreground.1");
-    --calcite-split-button-background: transparent;
   }
 }
 
 :host([appearance="outline"]),
 :host([appearance="outline-fill"]) {
-  &:host([kind="brand"]),
-  &:host([kind="danger"]),
-  &:host([kind="neutral"]),
-  &:host([kind="inverse"]) {
-    --calcite-split-button-background: transparent;
-  }
+  --calcite-split-button-background: transparent;
   &:host([kind="brand"]) {
     --calcite-split-button-divider: theme("colors.brand");
   }
@@ -125,12 +118,6 @@
   calcite-dropdown > calcite-button {
     @apply pointer-events-none;
   }
-  &:host([appearance="outline-fill"]),
-  &:host([appearance="outline"]) {
-    .divider-container {
-      background-color: transparent;
-    }
-  }
 }
 
 @include base-component();