feat(ui): add multiselect selection microinteractions

- Animate selected pills and item feedback in multiselect components
- Add checkbox state transitions for provider group selections
- Cover shared selection motion with focused unit tests

ui/components/shadcn/checkbox/checkbox.test.tsx

@@ -0,0 +1,52 @@
+import { render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { useState } from "react";
+import { describe, expect, it } from "vitest";
+
+import { Checkbox } from "./checkbox";
+
+function ControlledCheckbox() {
+  const [checked, setChecked] = useState(false);
+
+  return (
+    <Checkbox
+      aria-label="Select provider"
+      checked={checked}
+      onCheckedChange={(value) => setChecked(value === true)}
+    />
+  );
+}
+
+describe("Checkbox", () => {
+  it("animates the background and check mark as one state change", async () => {
+    // Given - A controlled checkbox in the unchecked state
+    const user = userEvent.setup();
+    render(<ControlledCheckbox />);
+
+    const checkbox = screen.getByRole("checkbox", { name: /select provider/i });
+    const indicator = checkbox.querySelector(
+      "[data-slot='checkbox-indicator']",
+    );
+
+    // When - The user checks the checkbox
+    await user.click(checkbox);
+
+    // Then - The background and check mark transitions use the same timing
+    expect(checkbox).toHaveClass(
+      "transition-colors",
+      "duration-200",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+    expect(indicator).toHaveClass(
+      "transition-[opacity,transform]",
+      "duration-200",
+      "ease-out",
+      "data-[state=checked]:scale-100",
+      "data-[state=checked]:opacity-100",
+      "data-[state=unchecked]:scale-75",
+      "data-[state=unchecked]:opacity-0",
+      "motion-reduce:transition-none",
+    );
+  });
+});

ui/components/shadcn/checkbox/checkbox.tsx

@@ -41,7 +41,7 @@ function Checkbox({
       checked={indeterminate ? "indeterminate" : checked}
       className={cn(
         // Base styles
-        "peer shrink-0 rounded-sm border transition-all outline-none",
+        "peer shrink-0 rounded-sm border transition-colors duration-200 ease-out outline-none motion-reduce:transition-none",
         sizeStyles.root,
         // Default state
         "bg-bg-input-primary border-border-input-primary shadow-[0_1px_2px_0_rgba(0,0,0,0.1)]",
@@ -58,8 +58,9 @@ function Checkbox({
       {...props}
     >
       <CheckboxPrimitive.Indicator
+        forceMount
         data-slot="checkbox-indicator"
-        className="grid place-content-center text-current transition-none"
+        className="grid place-content-center text-current transition-[opacity,transform] duration-200 ease-out data-[state=checked]:scale-100 data-[state=checked]:opacity-100 data-[state=indeterminate]:scale-100 data-[state=indeterminate]:opacity-100 data-[state=unchecked]:scale-75 data-[state=unchecked]:opacity-0 motion-reduce:scale-100 motion-reduce:transition-none"
       >
         {indeterminate || checked === "indeterminate" ? (
           <MinusIcon className={sizeStyles.icon} />

ui/components/shadcn/select/enhanced-multi-select.test.tsx

@@ -0,0 +1,138 @@
+import { render, screen, within } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { beforeAll, describe, expect, it, vi } from "vitest";
+
+import { EnhancedMultiSelect } from "./enhanced-multi-select";
+
+const options = [
+  { value: "aws-prod", label: "Production AWS" },
+  { value: "azure-dev", label: "Development Azure" },
+];
+
+beforeAll(() => {
+  global.ResizeObserver = class ResizeObserver {
+    observe = vi.fn();
+    unobserve = vi.fn();
+    disconnect = vi.fn();
+  } as unknown as typeof ResizeObserver;
+
+  Object.defineProperty(HTMLElement.prototype, "scrollIntoView", {
+    configurable: true,
+    value: vi.fn(),
+  });
+});
+
+describe("EnhancedMultiSelect", () => {
+  it("uses visible trigger and chevron open-state motion", () => {
+    render(
+      <EnhancedMultiSelect
+        options={options}
+        onValueChange={() => {}}
+        placeholder="Select providers"
+        aria-label="Select providers"
+      />,
+    );
+
+    const trigger = screen.getByRole("combobox", { name: /select providers/i });
+    const icon = trigger.querySelector("svg");
+
+    expect(trigger).toHaveClass(
+      "group",
+      "transition-[background-color,border-color,color,box-shadow]",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+    expect(icon).toHaveClass(
+      "transition-transform",
+      "duration-200",
+      "ease-out",
+      "group-aria-expanded:rotate-180",
+      "motion-reduce:rotate-0",
+      "motion-reduce:transition-none",
+    );
+  });
+
+  it("animates item selection feedback and checkbox visibility", async () => {
+    const user = userEvent.setup();
+
+    render(
+      <EnhancedMultiSelect
+        options={options}
+        onValueChange={() => {}}
+        placeholder="Select providers"
+        aria-label="Select providers"
+      />,
+    );
+
+    await user.click(
+      screen.getByRole("combobox", { name: /select providers/i }),
+    );
+
+    const option = screen.getByRole("option", { name: /production aws/i });
+    const checkbox = option.querySelector("[data-slot='checkbox']");
+    const checkboxIndicator = checkbox?.querySelector(
+      "[data-slot='checkbox-indicator']",
+    );
+
+    expect(option).toHaveClass(
+      "transition-colors",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+    expect(checkbox).toHaveClass(
+      "transition-colors",
+      "duration-200",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+    expect(checkboxIndicator).toHaveClass(
+      "transition-[opacity,transform]",
+      "duration-200",
+      "ease-out",
+      "data-[state=checked]:scale-100",
+      "data-[state=checked]:opacity-100",
+      "data-[state=unchecked]:scale-75",
+      "data-[state=unchecked]:opacity-0",
+      "motion-reduce:transition-none",
+    );
+  });
+
+  it("animates selected pills when values are added to the trigger", async () => {
+    const user = userEvent.setup();
+    const onValueChange = vi.fn();
+
+    render(
+      <EnhancedMultiSelect
+        options={options}
+        onValueChange={onValueChange}
+        placeholder="Select providers"
+        aria-label="Select providers"
+      />,
+    );
+
+    await user.click(
+      screen.getByRole("combobox", { name: /select providers/i }),
+    );
+    await user.click(screen.getByRole("option", { name: /production aws/i }));
+
+    const pill = within(
+      screen.getByRole("combobox", { name: /select providers/i }),
+    )
+      .getByText("Production AWS")
+      .closest("[data-slot='enhanced-multiselect-pill']");
+
+    expect(onValueChange).toHaveBeenCalledWith(["aws-prod"]);
+    expect(pill).toHaveClass(
+      "animate-in",
+      "fade-in-0",
+      "zoom-in-95",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:animate-none",
+      "motion-reduce:transform-none",
+      "motion-reduce:transition-none",
+    );
+  });
+});

ui/components/shadcn/select/enhanced-multi-select.tsx

@@ -183,7 +183,7 @@ export function EnhancedMultiSelect({
           aria-controls={open ? listboxId : undefined}
           aria-label={ariaLabel}
           className={cn(
-            "border-border-input-primary bg-bg-input-primary text-text-neutral-primary data-[placeholder]:text-text-neutral-tertiary [&_svg:not([class*='text-'])]:text-text-neutral-tertiary aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive hover:bg-bg-input-primary active:bg-bg-input-primary focus-visible:border-border-input-primary-press focus-visible:ring-border-input-primary-press flex h-auto min-h-12 w-full items-center justify-between gap-2 rounded-lg border px-3 py-2 text-sm shadow-xs transition-[color,box-shadow] outline-none focus-visible:ring-1 focus-visible:ring-offset-1 [&_svg]:pointer-events-auto",
+            "group border-border-input-primary bg-bg-input-primary text-text-neutral-primary data-[placeholder]:text-text-neutral-tertiary [&_svg:not([class*='text-'])]:text-text-neutral-tertiary aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive hover:bg-bg-input-primary active:bg-bg-input-primary focus-visible:border-border-input-primary-press focus-visible:ring-border-input-primary-press flex h-auto min-h-12 w-full items-center justify-between gap-2 rounded-lg border px-3 py-2 text-sm shadow-xs transition-[background-color,border-color,color,box-shadow] duration-150 ease-out outline-none focus-visible:ring-1 focus-visible:ring-offset-1 motion-reduce:transition-none [&_svg]:pointer-events-auto",
             disabled && "cursor-not-allowed opacity-50",
             className,
           )}
@@ -200,7 +200,8 @@ export function EnhancedMultiSelect({
                       <Badge
                         key={value}
                         variant="tag"
-                        className="m-1 cursor-default [&>svg]:pointer-events-auto"
+                        data-slot="enhanced-multiselect-pill"
+                        className="animate-in fade-in-0 zoom-in-95 m-1 cursor-default duration-150 ease-out motion-reduce:transform-none motion-reduce:animate-none motion-reduce:transition-none [&>svg]:pointer-events-auto"
                       >
                         <span className="cursor-default">{option.label}</span>
                         <span
@@ -224,7 +225,8 @@ export function EnhancedMultiSelect({
                 {selectedValues.length > maxCount && (
                   <Badge
                     variant="tag"
-                    className="m-1 cursor-default [&>svg]:pointer-events-auto"
+                    data-slot="enhanced-multiselect-pill"
+                    className="animate-in fade-in-0 zoom-in-95 m-1 cursor-default duration-150 ease-out motion-reduce:transform-none motion-reduce:animate-none motion-reduce:transition-none [&>svg]:pointer-events-auto"
                   >
                     {`+ ${selectedValues.length - maxCount} more`}
                     <span
@@ -271,7 +273,7 @@ export function EnhancedMultiSelect({
                   className="flex h-full min-h-6"
                 />
                 <ChevronDown
-                  className="text-text-neutral-tertiary mx-2 h-4 cursor-pointer"
+                  className="text-text-neutral-tertiary mx-2 h-4 cursor-pointer transition-transform duration-200 ease-out group-aria-expanded:rotate-180 motion-reduce:rotate-0 motion-reduce:transition-none"
                   aria-hidden="true"
                 />
               </div>
@@ -281,7 +283,7 @@ export function EnhancedMultiSelect({
               <span className="text-text-neutral-tertiary mx-3 text-sm">
                 {placeholder}
               </span>
-              <ChevronDown className="text-text-neutral-tertiary mx-2 h-4 cursor-pointer" />
+              <ChevronDown className="text-text-neutral-tertiary mx-2 h-4 cursor-pointer transition-transform duration-200 ease-out group-aria-expanded:rotate-180 motion-reduce:rotate-0 motion-reduce:transition-none" />
             </div>
           )}
         </Button>
@@ -339,7 +341,7 @@ export function EnhancedMultiSelect({
                     aria-selected={isSelected}
                     aria-disabled={option.disabled}
                     className={cn(
-                      "cursor-pointer",
+                      "cursor-pointer transition-colors duration-150 ease-out motion-reduce:transition-none",
                       option.disabled && "cursor-not-allowed opacity-50",
                     )}
                     disabled={option.disabled}

ui/components/shadcn/select/multiselect.test.tsx

@@ -83,6 +83,138 @@ describe("MultiSelect", () => {
     ).not.toBeInTheDocument();
   });
 
+  it("uses visible trigger and chevron open-state motion", () => {
+    render(
+      <MultiSelect values={[]} onValuesChange={() => {}}>
+        <MultiSelectTrigger>
+          <MultiSelectValue placeholder="Select accounts" />
+        </MultiSelectTrigger>
+        <MultiSelectContent search={false}>
+          <MultiSelectItem value="aws-prod">Production AWS</MultiSelectItem>
+        </MultiSelectContent>
+      </MultiSelect>,
+    );
+
+    const trigger = screen.getByRole("combobox");
+    const icon = trigger.querySelector("svg");
+
+    expect(trigger).toHaveClass(
+      "transition-[background-color,border-color,color,box-shadow]",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+    expect(icon).toHaveClass(
+      "transition-transform",
+      "duration-200",
+      "ease-out",
+      "group-aria-expanded:rotate-180",
+      "motion-reduce:rotate-0",
+      "motion-reduce:transition-none",
+    );
+  });
+
+  it("uses visible content open and close motion", async () => {
+    const user = userEvent.setup();
+
+    render(
+      <MultiSelect values={[]} onValuesChange={() => {}}>
+        <MultiSelectTrigger>
+          <MultiSelectValue placeholder="Select accounts" />
+        </MultiSelectTrigger>
+        <MultiSelectContent search={false}>
+          <MultiSelectItem value="aws-prod">Production AWS</MultiSelectItem>
+        </MultiSelectContent>
+      </MultiSelect>,
+    );
+
+    await user.click(screen.getByRole("combobox"));
+
+    const content = document.querySelector("[data-slot='multiselect-content']");
+
+    expect(content).toHaveClass(
+      "duration-200",
+      "ease-out",
+      "data-[state=open]:animate-in",
+      "data-[state=open]:fade-in-0",
+      "data-[state=open]:zoom-in-95",
+      "data-[state=closed]:animate-out",
+      "data-[state=closed]:fade-out-0",
+      "data-[state=closed]:zoom-out-95",
+      "data-[state=closed]:duration-100",
+      "data-[state=closed]:ease-in",
+      "motion-reduce:animate-none",
+      "motion-reduce:transform-none",
+      "motion-reduce:transition-none",
+    );
+  });
+
+  it("animates item selection feedback and check visibility", async () => {
+    const user = userEvent.setup();
+
+    render(
+      <MultiSelect defaultValues={[]} onValuesChange={() => {}}>
+        <MultiSelectTrigger>
+          <MultiSelectValue placeholder="Select accounts" />
+        </MultiSelectTrigger>
+        <MultiSelectContent search={false}>
+          <MultiSelectItem value="aws-prod">Production AWS</MultiSelectItem>
+        </MultiSelectContent>
+      </MultiSelect>,
+    );
+
+    await user.click(screen.getByRole("combobox"));
+
+    const option = screen.getByRole("option", { name: /production aws/i });
+    const checkIcon = option.querySelector("svg");
+
+    expect(option).toHaveClass(
+      "transition-colors",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+    expect(checkIcon).toHaveClass(
+      "transition-[opacity,transform]",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:transition-none",
+    );
+  });
+
+  it("animates selected pills when values are added to the trigger", async () => {
+    const user = userEvent.setup();
+
+    render(
+      <MultiSelect defaultValues={[]} onValuesChange={() => {}}>
+        <MultiSelectTrigger>
+          <MultiSelectValue placeholder="Select accounts" />
+        </MultiSelectTrigger>
+        <MultiSelectContent search={false}>
+          <MultiSelectItem value="aws-prod">Production AWS</MultiSelectItem>
+        </MultiSelectContent>
+      </MultiSelect>,
+    );
+
+    await user.click(screen.getByRole("combobox"));
+    await user.click(screen.getByRole("option", { name: /production aws/i }));
+
+    const pill = within(screen.getByRole("combobox"))
+      .getByText("Production AWS")
+      .closest("[data-selected-item]");
+
+    expect(pill).toHaveClass(
+      "animate-in",
+      "fade-in-0",
+      "zoom-in-95",
+      "duration-150",
+      "ease-out",
+      "motion-reduce:animate-none",
+      "motion-reduce:transform-none",
+      "motion-reduce:transition-none",
+    );
+  });
+
   it("filters items without crashing when search is enabled", async () => {
     const user = userEvent.setup();
 

ui/components/shadcn/select/multiselect.tsx

@@ -153,15 +153,14 @@ export function MultiSelectTrigger({
         data-slot="multiselect-trigger"
         data-size={size}
         className={cn(
-          "border-border-input-primary bg-bg-input-primary text-bg-button-secondary data-[placeholder]:text-bg-button-secondary [&_svg:not([class*='text-'])]:text-bg-button-secondary aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:bg-input/30 dark:hover:bg-input/50 focus-visible:border-border-input-primary-press focus-visible:ring-border-input-primary-press flex w-full items-center justify-between gap-2 overflow-hidden rounded-lg border px-4 py-3 text-sm whitespace-nowrap shadow-xs transition-[color,box-shadow] outline-none focus-visible:ring-1 focus-visible:ring-offset-1 disabled:cursor-not-allowed disabled:opacity-50 data-[size=default]:h-[52px] data-[size=sm]:h-10 *:data-[slot=multiselect-value]:line-clamp-1 *:data-[slot=multiselect-value]:flex *:data-[slot=multiselect-value]:items-center *:data-[slot=multiselect-value]:gap-2 dark:focus-visible:ring-slate-400 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-6",
+          "group border-border-input-primary bg-bg-input-primary text-bg-button-secondary data-[placeholder]:text-bg-button-secondary [&_svg:not([class*='text-'])]:text-bg-button-secondary aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:bg-input/30 dark:hover:bg-input/50 focus-visible:border-border-input-primary-press focus-visible:ring-border-input-primary-press flex w-full items-center justify-between gap-2 overflow-hidden rounded-lg border px-4 py-3 text-sm whitespace-nowrap shadow-xs transition-[background-color,border-color,color,box-shadow] duration-150 ease-out outline-none focus-visible:ring-1 focus-visible:ring-offset-1 disabled:cursor-not-allowed disabled:opacity-50 data-[size=default]:h-[52px] data-[size=sm]:h-10 *:data-[slot=multiselect-value]:line-clamp-1 *:data-[slot=multiselect-value]:flex *:data-[slot=multiselect-value]:items-center *:data-[slot=multiselect-value]:gap-2 motion-reduce:transition-none dark:focus-visible:ring-slate-400 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-6",
           className,
         )}
       >
         {children}
         <ChevronDown
           className={cn(
-            "text-bg-button-secondary size-6 shrink-0 opacity-70 transition-transform duration-200",
-            open && "rotate-180",
+            "text-bg-button-secondary size-6 shrink-0 opacity-70 transition-transform duration-200 ease-out group-aria-expanded:rotate-180 motion-reduce:rotate-0 motion-reduce:transition-none",
           )}
         />
       </Button>
@@ -267,7 +266,7 @@ export function MultiSelectValue({
           <Badge
             variant="tag"
             data-selected-item
-            className="group flex items-center gap-1.5 px-2 py-1 text-xs font-medium"
+            className="group animate-in fade-in-0 zoom-in-95 flex items-center gap-1.5 px-2 py-1 text-xs font-medium duration-150 ease-out motion-reduce:transform-none motion-reduce:animate-none motion-reduce:transition-none"
             key={value}
             onClick={
               clickToRemove
@@ -415,7 +414,7 @@ export function MultiSelectItem({
       keywords={keywords}
       data-slot="multiselect-item"
       className={cn(
-        "focus:bg-accent focus:text-accent-foreground [&_svg:not([class*='text-'])]:text-bg-button-secondary text-bg-button-secondary my-1 flex w-full cursor-pointer items-center justify-between gap-3 overflow-hidden rounded-lg px-4 py-3 text-sm outline-hidden select-none first:mt-0 last:mb-0 hover:bg-slate-200 data-[disabled=true]:pointer-events-none data-[disabled=true]:opacity-50 dark:hover:bg-slate-700/50 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-5",
+        "focus:bg-accent focus:text-accent-foreground [&_svg:not([class*='text-'])]:text-bg-button-secondary text-bg-button-secondary my-1 flex w-full cursor-pointer items-center justify-between gap-3 overflow-hidden rounded-lg px-4 py-3 text-sm outline-hidden transition-colors duration-150 ease-out select-none first:mt-0 last:mb-0 hover:bg-slate-200 data-[disabled=true]:pointer-events-none data-[disabled=true]:opacity-50 motion-reduce:transition-none dark:hover:bg-slate-700/50 [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-5",
         isSelected && "bg-slate-100 dark:bg-slate-800/50",
         disabled && "cursor-not-allowed opacity-50 hover:bg-transparent",
         className,
@@ -431,8 +430,8 @@ export function MultiSelectItem({
       </span>
       <CheckIcon
         className={cn(
-          "text-bg-button-secondary size-5 shrink-0",
-          isSelected ? "opacity-100" : "opacity-0",
+          "text-bg-button-secondary size-5 shrink-0 transition-[opacity,transform] duration-150 ease-out motion-reduce:transition-none",
+          isSelected ? "scale-100 opacity-100" : "scale-95 opacity-0",
         )}
       />
     </CommandItem>