diff --git a/src/index.css b/src/index.css
index cf3caea1..e9539472 100644
--- a/src/index.css
+++ b/src/index.css
@@ -90,16 +90,29 @@ body.lotus-transparent[data-background="gradient"]::before {
   display: none !important;
 }
 
+/* [cinny #43] lotusHostControls=1: the host renders its own call bar, so EC's
+footer is hidden but stays in the DOM and in layout-independent position. */
+body.lotus-host-controls [data-testid="footer-container"] {
+  position: absolute !important;
+  visibility: hidden !important;
+}
+
 /* [lotus] Native Lotus/TDS theme, applied when lotusTheme=1, instead of the
 host injecting CSS into the iframe after load. Overrides Compound design tokens
 with Lotus values at the source so theming is complete and flash-free. Extend
 this block with the full Lotus token map from the design system; the canvas
 override below is a safe starting point that matches the Lotus dark surface. */
 body.lotus-theme {
-  --cpd-color-bg-canvas-default: #0c0d10;
   --video-tile-background: var(--cpd-color-bg-subtle-secondary);
 }
 
+/* Dark themes only: in the light theme this near-black canvas sat behind
+light-theme (dark) text, e.g. the tile name tags were unreadable. */
+body.lotus-theme.cpd-theme-dark,
+body.lotus-theme.cpd-theme-dark-hc {
+  --cpd-color-bg-canvas-default: #0c0d10;
+}
+
 /* [lotus #21] Subtle contrast guard for elements that sit directly on the
 transparent canvas (no opaque tile background behind them) when
 lotusTransparent is set: the host's real wallpaper is unknown to us, so a
diff --git a/src/useTheme.ts b/src/useTheme.ts
index 1e3a2e16..eee8699a 100644
--- a/src/useTheme.ts
+++ b/src/useTheme.ts
@@ -76,7 +76,17 @@ export const useTheme = (): void => {
           "lotusTheme anyway since the two flags are only meaningful together.",
       );
     }
-    if (lotusTheme || lotusTransparent)
+    if (lotusTheme || lotusTransparent) {
       document.body.classList.add("lotus-theme");
+      // [cinny #43] The frame's root colour scheme must match the host's, or
+      // the browser paints an opaque backdrop behind the transparent frame.
+      // (The host used to inject `:root { color-scheme }` for this.)
+      document.documentElement.style.colorScheme = theme;
+    }
+    // [cinny #43] The host draws its own call bar: hide EC's footer, but keep
+    // it in the DOM (the host still clicks its screenshare button on engines
+    // without Capability Delegation). Replaces the host's injected styles.
+    if (lotusFlag("lotusHostControls"))
+      document.body.classList.add("lotus-host-controls");
   }, [previousTheme, requestedTheme]);
 };