Add floating labels to InputField

src/app/components/client/InputField.module.scss

@@ -7,14 +7,36 @@
   flex-direction: column;
   position: relative;
 
+  .inputFieldWrapper {
+    position: relative;
+  }
+
+  .floatingLabel {
+    background: $color-white;
+    border-radius: $border-radius-sm;
+    color: $color-black;
+    display: inline-block;
+    // Add a bit more space: The next spacing step is too much.
+    left: calc($spacing-sm * 1.5);
+    line-height: 1em;
+    padding: 0 calc($spacing-xs * 0.5);
+    pointer-events: none;
+    position: absolute;
+    top: 50%;
+    transform-origin: top left;
+    transform: translate(-0.05em, -50%) scale(1);
+    transition: transform 0.2s ease-in-out;
+    user-select: none;
+  }
+
   .inputField {
     border: 1px solid $color-grey-30;
     border-radius: $border-radius-sm;
     color: $color-black;
-    // Add a bit more vertical space: The next spacing step is too much.
-    padding: calc($spacing-sm * 1.5) $spacing-md;
+    // Add a bit more space: The next spacing step is too much.
+    padding: calc($spacing-sm * 1.5);
+    width: 100%;
 
-    &::placeholder,
     &.noValue {
       color: $color-grey-40;
     }
@@ -39,6 +61,25 @@
     }
   }
 
+  &:has(.floatingLabel) {
+    ::placeholder {
+      @include visually-hidden;
+    }
+    .inputField {
+      // Move the value string off-center.
+      padding: calc($spacing-md * 1.25) calc($spacing-sm * 1.5) $spacing-xs;
+    }
+  }
+
+  &:focus-within,
+  &:not(:has(:placeholder-shown)) {
+    .floatingLabel {
+      color: $color-grey-40;
+      // Make the floating label visually align with the input value.
+      transform: translate(-0.05em, -115%) scale(0.75);
+    }
+  }
+
   .inputLabel {
     font-weight: 600;
     margin-bottom: $spacing-sm;

src/app/components/client/InputField.test.tsx

@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+import { expect } from "@jest/globals";
+import { render } from "@testing-library/react";
+import { composeStory } from "@storybook/react";
+import { axe } from "jest-axe";
+import Meta, {
+  TextInputFieldEmpty,
+  TextInputFieldEmptyFloatingLabel,
+  TextInputFieldFilled,
+  TextInputFieldFilledFloatingLabel,
+} from "./stories/InputField.stories";
+
+describe("InputField", () => {
+  test.each([
+    TextInputFieldEmpty,
+    TextInputFieldFilled,
+    TextInputFieldEmptyFloatingLabel,
+    TextInputFieldFilledFloatingLabel,
+  ])("passes the axe accessibility test suite for %s", async (component) => {
+    const ComposedInput = composeStory(component, Meta);
+    const { container } = render(<ComposedInput hasFloatingLabel />);
+    expect(await axe(container)).toHaveNoViolations();
+  });
+});

src/app/components/client/InputField.tsx

@@ -13,6 +13,7 @@ import { useL10n } from "../../hooks/l10n";
 export const InputField = (
   props: AriaTextFieldProps & {
     iconButton?: ReactNode;
+    hasFloatingLabel?: boolean;
   },
 ) => {
   const { isRequired, label, isInvalid, value, description } = props;
@@ -29,13 +30,14 @@ export const InputField = (
   return (
     <div className={styles.input}>
       {label && (
-        <label {...labelProps} className={styles.inputLabel}>
-          {label}
-          {
-            // TODO: Add unit test when changing this code:
-            /* c8 ignore next */
-            isRequired ? <span aria-hidden="true">*</span> : ""
+        <label
+          {...labelProps}
+          className={
+            props.hasFloatingLabel ? styles.floatingLabel : styles.inputLabel
           }
+        >
+          {label}
+          {isRequired ? <span aria-hidden="true">*</span> : ""}
         </label>
       )}
       <input

src/app/components/client/stories/InputField.stories.ts

@@ -81,3 +81,22 @@ export const DateInputFieldInvalidWithMessage: Story = {
     errorMessage: "Select a date",
   },
 };
+
+export const TextInputFieldEmptyFloatingLabel: Story = {
+  args: {
+    label: "Text input floating label",
+    placeholder: "Type here",
+    type: "text",
+    hasFloatingLabel: true,
+  },
+};
+
+export const TextInputFieldFilledFloatingLabel: Story = {
+  args: {
+    label: "Text input floating label",
+    placeholder: "Type here",
+    type: "text",
+    value: "Input is filled",
+    hasFloatingLabel: true,
+  },
+};