diff --git a/DeepDrftShared.Client/Components/ParallaxImage.razor b/DeepDrftShared.Client/Components/ParallaxImage.razor
new file mode 100644
index 0000000..e8aa3b7
--- /dev/null
+++ b/DeepDrftShared.Client/Components/ParallaxImage.razor
@@ -0,0 +1,20 @@
+@inherits ParallaxImageBase
+
+
+
+
+
+
+ @if (Image2 != null)
+ {
+
+
+ }
+
diff --git a/DeepDrftShared.Client/Components/ParallaxImage.razor.cs b/DeepDrftShared.Client/Components/ParallaxImage.razor.cs
new file mode 100644
index 0000000..2ced165
--- /dev/null
+++ b/DeepDrftShared.Client/Components/ParallaxImage.razor.cs
@@ -0,0 +1,124 @@
+using Microsoft.AspNetCore.Components;
+using Microsoft.JSInterop;
+
+namespace DeepDrftShared.Client.Components;
+
+///
+/// Scroll-driven parallax image window. As the component scrolls up through the viewport,
+/// the image pans through the window faster than the page scrolls. An optional second image
+/// crossfades in on hover (pure CSS). A flag breaks the container out
+/// of parent padding to span the viewport.
+///
+///
+/// Progressive enhancement: renders a static framed image at SSR; the parallax attaches after
+/// interactive boot via OnAfterRenderAsync(firstRender). When
+/// is left null, the window renders at 300px and recomputes to naturalHeight/2 once the image
+/// decodes — this can cause a one-time layout shift on first paint. Pass an explicit
+/// for above-the-fold hero usage to avoid the shift.
+///
+public abstract class ParallaxImageBase : ComponentBase, IAsyncDisposable
+{
+ [Inject] private IJSRuntime JS { get; set; } = default!;
+
+ /// Primary image URL, shown at rest.
+ [Parameter, EditorRequired] public string Image1 { get; set; } = default!;
+
+ /// Optional hover image (assumed same dimensions as ).
+ [Parameter] public string? Image2 { get; set; }
+
+ /// Accessible name for . When null, the window is decorative.
+ [Parameter] public string? Alt1 { get; set; }
+
+ /// Accessible name for (only relevant if it adds semantic meaning).
+ [Parameter] public string? Alt2 { get; set; }
+
+ /// CSS height of the parallax window. When null, renders at 300px and recomputes to naturalHeight/2.
+ [Parameter] public string? WindowHeight { get; set; }
+
+ /// background-size width.
+ [Parameter] public string ImageWidth { get; set; } = "auto";
+
+ /// background-size height.
+ [Parameter] public string ImageHeight { get; set; } = "auto";
+
+ /// When true, stretches the container to 100vw via a negative-margin breakout.
+ [Parameter] public bool FullWidth { get; set; }
+
+ /// Speed multiplier, clamped to [0,1] in the JS module.
+ [Parameter] public double ParallaxSpeed { get; set; } = 0.5;
+
+ /// When false: top-on-entry to bottom-at-top. When true: inverted.
+ [Parameter] public bool InvertDirection { get; set; }
+
+ /// Extra CSS classes on the outer element.
+ [Parameter] public string? Class { get; set; }
+
+ protected ElementReference WindowRef;
+ protected string WindowHeightValue { get; private set; } = "300px";
+
+ private IJSObjectReference? _module;
+ private DotNetObjectReference? _dotNetRef;
+ private string? _handle;
+
+ protected override void OnParametersSet()
+ {
+ WindowHeightValue = WindowHeight ?? "300px";
+ }
+
+ protected override async Task OnAfterRenderAsync(bool firstRender)
+ {
+ if (!firstRender)
+ {
+ return;
+ }
+
+ _module = await JS.InvokeAsync(
+ "import", "./_content/DeepDrftShared.Client/js/parallax/parallax.js");
+
+ var reportNaturalHeight = WindowHeight == null;
+ if (reportNaturalHeight)
+ {
+ _dotNetRef = DotNetObjectReference.Create(this);
+ }
+
+ _handle = await _module.InvokeAsync(
+ "register",
+ WindowRef,
+ new { speed = ParallaxSpeed, invertDirection = InvertDirection, onNaturalHeight = reportNaturalHeight, image1 = Image1 },
+ _dotNetRef);
+ }
+
+ ///
+ /// Invoked by the JS module once the background image decodes, when the consumer left
+ /// null. Sets the window height to half the image's natural height.
+ ///
+ [JSInvokable]
+ public void SetNaturalHeight(double naturalHeightPx)
+ {
+ WindowHeightValue = $"{(int)(naturalHeightPx / 2)}px";
+ StateHasChanged();
+ }
+
+ public async ValueTask DisposeAsync()
+ {
+ if (_module != null)
+ {
+ try
+ {
+ if (_handle != null)
+ {
+ await _module.InvokeVoidAsync("unregister", _handle);
+ }
+
+ await _module.DisposeAsync();
+ }
+ catch (JSDisconnectedException)
+ {
+ // Circuit already torn down (e.g. browser navigated away) — nothing to clean up.
+ }
+ }
+
+ _dotNetRef?.Dispose();
+ GC.SuppressFinalize(this);
+ }
+}
diff --git a/DeepDrftShared.Client/Components/ParallaxImage.razor.css b/DeepDrftShared.Client/Components/ParallaxImage.razor.css
new file mode 100644
index 0000000..25283a3
--- /dev/null
+++ b/DeepDrftShared.Client/Components/ParallaxImage.razor.css
@@ -0,0 +1,48 @@
+.parallax-window {
+ position: relative;
+ overflow: hidden;
+ height: var(--window-height, 300px);
+ width: 100%;
+}
+
+.parallax-window.full-width {
+ width: 100vw;
+ position: relative;
+ left: 50%;
+ right: 50%;
+ margin-left: -50vw;
+ margin-right: -50vw;
+}
+
+.layer {
+ position: absolute;
+ top: 0;
+ left: 0;
+ right: 0;
+ bottom: 0;
+ background-repeat: no-repeat;
+ background-position: 50% var(--parallax-pos, 50%);
+}
+
+.layer-1 {
+ opacity: 1;
+}
+
+.layer-2 {
+ opacity: 0;
+ transition: opacity 400ms ease;
+}
+
+.parallax-window:hover .layer-2 {
+ opacity: 1;
+}
+
+@media (prefers-reduced-motion: reduce) {
+ .parallax-window {
+ --parallax-pos: 0%;
+ }
+
+ .layer-2 {
+ transition-duration: 0ms;
+ }
+}
diff --git a/DeepDrftShared.Client/DeepDrftShared.Client.csproj b/DeepDrftShared.Client/DeepDrftShared.Client.csproj
index aa30580..9e3db0a 100644
--- a/DeepDrftShared.Client/DeepDrftShared.Client.csproj
+++ b/DeepDrftShared.Client/DeepDrftShared.Client.csproj
@@ -19,4 +19,28 @@
+
+
+ all
+ runtime; build; native; contentfiles; analyzers; buildtransitive
+
+
+
+
+
+
+ false
+ Latest
+ true
+ true
+
+
+
+
+
+ Never
+ Never
+
+
+
diff --git a/DeepDrftShared.Client/Interop/parallax/parallax.ts b/DeepDrftShared.Client/Interop/parallax/parallax.ts
new file mode 100644
index 0000000..2cb06af
--- /dev/null
+++ b/DeepDrftShared.Client/Interop/parallax/parallax.ts
@@ -0,0 +1,137 @@
+/**
+ * parallax - scroll-driven background-position panning for ParallaxImage.
+ *
+ * Single Responsibility: own the parallax math and scroll/observer lifecycle.
+ * Blazor owns the component lifecycle and calls register/unregister; this module
+ * writes only the `--parallax-pos` CSS custom property — never concrete style.
+ */
+
+interface RegisterOptions {
+ speed: number; // ParallaxSpeed, clamped [0,1]
+ invertDirection: boolean; // selects the formula branch
+ onNaturalHeight?: boolean; // if true, report natural height via dotNetRef callback
+ image1?: string; // primary image URL, used by reportNaturalHeight probe
+}
+
+interface DotNetObjectReference {
+ invokeMethodAsync(methodName: string, ...args: unknown[]): Promise;
+}
+
+interface Handle {
+ element: HTMLElement;
+ options: RegisterOptions;
+ observer: IntersectionObserver;
+ scrollListener: (() => void) | null;
+ rafId: number | null;
+ dotNetRef: DotNetObjectReference | null;
+}
+
+const handles = new Map();
+
+let _handleCounter = 0;
+
+const reducedMotion = (): boolean =>
+ window.matchMedia('(prefers-reduced-motion: reduce)').matches;
+
+function clamp(value: number, min: number, max: number): number {
+ return Math.max(min, Math.min(max, value));
+}
+
+function applyParallax(handle: Handle): void {
+ const { element, options } = handle;
+ const rect = element.getBoundingClientRect();
+ const viewportH = window.innerHeight;
+
+ let progress = options.invertDirection
+ ? rect.top / viewportH
+ : 1 - rect.top / viewportH;
+ progress = clamp(progress, 0, 1);
+
+ const pos = progress * clamp(options.speed, 0, 1) * 100;
+ element.style.setProperty('--parallax-pos', `${pos}%`);
+}
+
+function attachScrollListener(handle: Handle): void {
+ if (handle.scrollListener || reducedMotion()) return;
+
+ const listener = (): void => {
+ if (handle.rafId !== null) return;
+ handle.rafId = requestAnimationFrame(() => {
+ handle.rafId = null;
+ applyParallax(handle);
+ });
+ };
+
+ handle.scrollListener = listener;
+ window.addEventListener('scroll', listener, { passive: true });
+ // Prime position immediately so entry isn't a frame behind the first scroll.
+ applyParallax(handle);
+}
+
+function detachScrollListener(handle: Handle): void {
+ if (handle.scrollListener) {
+ window.removeEventListener('scroll', handle.scrollListener);
+ handle.scrollListener = null;
+ }
+ if (handle.rafId !== null) {
+ cancelAnimationFrame(handle.rafId);
+ handle.rafId = null;
+ }
+}
+
+function reportNaturalHeight(handle: Handle): void {
+ if (!handle.dotNetRef || !handle.options.image1) return;
+
+ const probe = new Image();
+ probe.onload = (): void => {
+ handle.dotNetRef?.invokeMethodAsync('SetNaturalHeight', probe.naturalHeight);
+ };
+ probe.src = handle.options.image1;
+}
+
+export function register(
+ element: HTMLElement,
+ options: RegisterOptions,
+ dotNetRef?: DotNetObjectReference,
+): string {
+ const id = `parallax-${++_handleCounter}`;
+
+ const realObserver = new IntersectionObserver((entries) => {
+ for (const entry of entries) {
+ if (entry.isIntersecting) {
+ attachScrollListener(handle);
+ } else {
+ detachScrollListener(handle);
+ }
+ }
+ });
+
+ const handle: Handle = {
+ element,
+ options: { ...options, speed: clamp(options.speed, 0, 1) },
+ observer: realObserver,
+ scrollListener: null,
+ rafId: null,
+ dotNetRef: dotNetRef ?? null,
+ };
+
+ handle.observer.observe(element);
+
+ handles.set(id, handle);
+
+ if (options.onNaturalHeight) {
+ reportNaturalHeight(handle);
+ }
+
+ return id;
+}
+
+export function unregister(handleId: string): void {
+ const handle = handles.get(handleId);
+ if (!handle) return;
+
+ detachScrollListener(handle);
+ handle.observer.disconnect();
+ handle.dotNetRef = null;
+ handles.delete(handleId);
+}
diff --git a/DeepDrftShared.Client/tsconfig.json b/DeepDrftShared.Client/tsconfig.json
new file mode 100644
index 0000000..14e35a1
--- /dev/null
+++ b/DeepDrftShared.Client/tsconfig.json
@@ -0,0 +1,27 @@
+{
+ "compilerOptions": {
+ "target": "ESNext",
+ "module": "ESNext",
+ "esModuleInterop": true,
+ "allowSyntheticDefaultImports": true,
+ "forceConsistentCasingInFileNames": true,
+ "strict": true,
+ "skipLibCheck": true,
+ "noEmitOnError": true,
+ "removeComments": false,
+ "sourceMap": true,
+ "rootDir": "Interop",
+ "outDir": "wwwroot/js",
+ "sourceRoot": "/Interop",
+ "mapRoot": "/js"
+ },
+ "include": [
+ "Interop/**/*.ts"
+ ],
+ "exclude": [
+ "node_modules",
+ "bin/**/*",
+ "obj/**/*",
+ "publish/**/*"
+ ]
+}