fix(web): size contact shadows to content bounds

Lay flat card/tile/token meshes so the scene-level contact shadow has a
surface to project onto, and size the shadow plane to the measured content
bounds instead of a fixed 22-unit default that left small objects shadowless.
Give deck carousel cards their own soft radial shadow so the fanned arc reads
as floating over a floor.

apps/web/src/components/viewers/CardViewer.tsx

@@ -28,7 +28,12 @@ import type { ViewerProps } from '../viewers';
 export default function CardViewer({ object, fill }: ViewerProps) {
   return (
     <Scene fill={fill}>
-      <CardObjectMesh object={object} />
+      {/* Cards are authored standing (face in XY, thickness along Z); lay them
+          flat on the ground so the face points up like a card on a table, which
+          is also what the contact shadow needs to project. */}
+      <group rotation={[-Math.PI / 2, 0, 0]}>
+        <CardObjectMesh object={object} />
+      </group>
     </Scene>
   );
 }

apps/web/src/components/viewers/DeckViewer.tsx

@@ -63,6 +63,7 @@ export default function DeckViewer({ object, fill }: ViewerProps) {
       fit={false}
       autoRotate={false}
       fill={fill}
+      shadow={false}
       overlay={
         hasCards ? (
           <CarouselControls active={active} count={count} onStep={step} />
@@ -90,7 +91,11 @@ export default function DeckViewer({ object, fill }: ViewerProps) {
           />
         </>
       ) : (
-        <CardObjectMesh object={object} />
+        // No contained cards: show the deck object itself, laid flat so the
+        // shared scene's contact shadow has a surface to project onto.
+        <group rotation={[-Math.PI / 2, 0, 0]}>
+          <CardObjectMesh object={object} />
+        </group>
       )}
     </Scene>
   );
@@ -187,10 +192,69 @@ function CarouselCard({
   return (
     <group ref={group}>
       <CardObjectMesh object={card} />
+      {/* A soft radial shadow under this card; it inherits the card group's
+          position/rotation/scale, so it tweens with the card. Card meshes are
+          laid flat (face up), so the plane sits just below the card's bottom. */}
+      <CardShadow />
     </group>
   );
 }
 
+// A soft elliptical drop shadow under a single carousel card. The card mesh is
+// ~2 world-units tall (centered), so its bottom sits at local y = -1; we put a
+// radial-gradient plane just below it. I can't use `ContactShadows` here
+// because the card is a thin vertical panel — a top-down capture would only
+// catch a line. Instead we fake a soft ambient contact shadow with a gradient.
+const CARD_HALF_HEIGHT = 1;
+const SHADOW_SCALE = 2.6;
+
+function CardShadow() {
+  // A soft radial gradient, dark at the center fading to transparent — reads as
+  // a soft blob of shadow rather than a hard cast shadow.
+  const texture = useMemo(makeSoftShadowTexture, []);
+  return (
+    <mesh
+      position={[0, -CARD_HALF_HEIGHT, 0]}
+      rotation={[-Math.PI / 2, 0, 0]}
+      scale={[SHADOW_SCALE, SHADOW_SCALE, 1]}
+    >
+      <planeGeometry args={[1, 1]} />
+      <meshBasicMaterial map={texture} transparent depthWrite={false} />
+    </mesh>
+  );
+}
+
+/** Build a radial-gradient texture: dark center fading out to transparent. */
+function makeSoftShadowTexture(): THREE.Texture {
+  const size = 256;
+  const canvas = document.createElement('canvas');
+  canvas.width = canvas.height = size;
+  const ctx = canvas.getContext('2d');
+  if (!ctx) return new THREE.Texture();
+  const g = ctx.createRadialGradient(
+    size / 2,
+    size / 2,
+    0,
+    size / 2,
+    size / 2,
+    size / 2,
+  );
+  const stops: [number, number][] = [
+    [0, 0.55],
+    [0.45, 0.35],
+    [0.75, 0.12],
+    [1, 0],
+  ];
+  for (const [t, a] of stops) {
+    g.addColorStop(t, `rgba(0, 0, 0, ${a})`);
+  }
+  ctx.fillStyle = g;
+  ctx.fillRect(0, 0, size, size);
+  const texture = new THREE.CanvasTexture(canvas);
+  texture.needsUpdate = true;
+  return texture;
+}
+
 interface Slots {
   x: number;
   z: number;

apps/web/src/components/viewers/Scene.tsx

@@ -1,9 +1,10 @@
-import { Suspense, useEffect, useRef, useState, type ReactNode } from 'react';
+import { Suspense, useEffect, useRef, useState, type RefObject, type ReactNode } from 'react';
 import { Icon } from '@iconify/react';
-import { Canvas } from '@react-three/fiber';
+import { Canvas, useFrame } from '@react-three/fiber';
 import { Bounds, ContactShadows, Environment, Lightformer, OrbitControls, useProgress } from '@react-three/drei';
 import { BrightnessContrast, EffectComposer, ToneMapping, Vignette } from '@react-three/postprocessing';
 import { ToneMappingMode } from 'postprocessing';
+import * as THREE from 'three';
 
 /**
  * Shared 3D scene wrapper for object viewers. Provides a consistent camera,
@@ -39,6 +40,8 @@ export default function Scene({
   overlay,
   shadowScale = 22,
   maxPolarAngle = Math.PI,
+  shadowBlur = 0.012,
+  shadow = true,
 }: {
   children: ReactNode;
   autoRotate?: boolean;
@@ -52,11 +55,18 @@ export default function Scene({
   overlay?: ReactNode;
   /** Contact shadow plane size in world units; defaults to a generous 22. */
   shadowScale?: number;
+  /** Contact shadow blur as a fraction of the plane size; a larger value is softer. */
+  shadowBlur?: number;
+  /** Whether to render a scene-level contact shadow under the content (default true). */
+  shadow?: boolean;
   /** Max camera polar angle in radians; defaults to unrestricted (π). */
   maxPolarAngle?: number;
 }) {
   const containerRef = useRef<HTMLDivElement>(null);
   const [isFullscreen, setIsFullscreen] = useState(false);
+  // Points at the wrapped children so the shadow can measure the real content
+  // bounding box (independent of drei's `Bounds` camera fit).
+  const contentRef = useRef<THREE.Group>(null);
 
   useEffect(() => {
     const onChange = () => setIsFullscreen(!!document.fullscreenElement);
@@ -100,19 +110,15 @@ export default function Scene({
           <Lightformer intensity={1} color="#b3c7ff" position={[-5, 2, -1]} scale={[3, 3, 1]} />
         </Environment>
 
-        <Suspense fallback={null}>
-          <Bounds fit={fit} observe={fit} clip={fit}>{children}</Bounds>
-        </Suspense>
+        {shadow && (
+          <AdaptiveContactShadow shadowScale={shadowScale} shadowBlur={shadowBlur} contentRef={contentRef} />
+        )}
 
-        <ContactShadows
-          position={[0, -0.01, 0]}
-          opacity={0.2}
-          scale={shadowScale}
-          blur={shadowScale * 0.005}
-          far={shadowScale * 0.01}
-          resolution={1024}
-          color="#000000"
-        />
+        <Suspense fallback={null}>
+          <Bounds fit={fit} observe={fit} clip={fit}>
+            <group ref={contentRef}>{children}</group>
+          </Bounds>
+        </Suspense>
         <OrbitControls
           enablePan={enablePan}
           minDistance={0.01}
@@ -152,3 +158,84 @@ function LoadingOverlay() {
     </div>
   );
 }
+
+/**
+ * A contact shadow sized and placed to the scene's actual content bounds.
+ *
+ * A fixed-size shadow plane baked for a 2-unit token is invisible to a whole
+ * card or model ten times larger, so the plane is (re)sized to the bounding
+ * box of whatever is wrapped in the scene, measured each frame from a ref.
+ * Keeping it scene-level (instead of per mesh) keeps it world-horizontal at
+ * the table and costs one shadow render per frame even when there are many
+ * meshes, which per-mesh planes would multiply.
+ *
+ * The plane sits on the very bottom (y minimum) of the content, centered on
+ * its footprint, and spans a bit wider so the shadow edge doesn't fall inside
+ * the object. `far` covers the full content height so tall objects aren't
+ * clipped. Falls back to `shadowScale` while the bounds are still empty.
+ */
+function AdaptiveContactShadow({
+  shadowScale,
+  shadowBlur,
+  contentRef,
+}: {
+  shadowScale: number;
+  shadowBlur: number;
+  contentRef: RefObject<THREE.Group | null>;
+}) {
+  // Current computed shadow config, kept in a ref so it's stable between frames
+  // and only recomputed when the content bounds actually change.
+  const state = useRef({ scale: 0, posX: 0, posY: 0, posZ: 0, far: 0 });
+  // Scratch box, reused each frame to avoid allocations.
+  const box = useRef(new THREE.Box3()).current;
+
+  useFrame(() => {
+    const content = contentRef.current;
+    if (!content) return;
+    content.updateWorldMatrix(true, true);
+    box.setFromObject(content);
+    if (box.isEmpty()) return;
+
+    const size = box.getSize(new THREE.Vector3());
+    const center = box.getCenter(new THREE.Vector3());
+    // The shadow plane rests on the very bottom of the content, centered on its
+    // footprint. `far` covers the full content height (plus margin) so the
+    // capture doesn't clip tall objects; `scale` covers the footprint.
+    const scale = Math.max(size.x, size.z) * SHADOW_PAD;
+    const posY = box.min.y;
+    const far = size.y + SHADOW_HEIGHT_MARGIN;
+    const s = state.current;
+    if (
+      scale !== s.scale ||
+      center.x !== s.posX ||
+      posY !== s.posY ||
+      center.z !== s.posZ ||
+      far !== s.far
+    ) {
+      Object.assign(s, { scale, posX: center.x, posY, posZ: center.z, far });
+    }
+  });
+
+  const s = state.current;
+  const scale = s.scale || shadowScale;
+  // Sit just below the lowest point of the content so it rests on it without
+  // intersecting; the plane uses a (fixed) world-horizontal orientation.
+  const position = [s.posX, s.posY - 0.01, s.posZ] as [number, number, number];
+
+  return (
+    <ContactShadows
+      position={position}
+      opacity={0.2}
+      scale={scale}
+      blur={scale * shadowBlur}
+      far={s.far || scale * 0.01}
+      resolution={1024}
+      color="#000000"
+    />
+  );
+}
+
+/** How far the shadow plane extends past the content footprint, as a multiple. */
+const SHADOW_PAD = 1.1;
+/** Extra capture depth beyond the content height, so the falloff edge isn't clipped. */
+const SHADOW_HEIGHT_MARGIN = 0.5;

apps/web/src/components/viewers/TileViewer.tsx

@@ -14,7 +14,10 @@ import type { ViewerProps } from '../viewers';
 export default function TileViewer({ object, fill }: ViewerProps) {
   return (
     <Scene fill={fill}>
-      <TileObjectMesh object={object} />
+      {/* Lay the tile flat on the ground (the mesh is authored standing). */}
+      <group rotation={[-Math.PI / 2, 0, 0]}>
+        <TileObjectMesh object={object} />
+      </group>
     </Scene>
   );
 }

apps/web/src/components/viewers/TokenViewer.tsx

@@ -12,7 +12,10 @@ import type { ViewerProps } from '../viewers';
 export default function TokenViewer({ object, fill }: ViewerProps) {
   return (
     <Scene fill={fill}>
-      <TokenObjectMesh object={object} />
+      {/* Lay the token flat on the ground (see CardViewer). */}
+      <group rotation={[-Math.PI / 2, 0, 0]}>
+        <TokenObjectMesh object={object} />
+      </group>
     </Scene>
   );
 }