Embedding Explorer: force light appearance via _dark theme variants

JS execution on HF Spaces is broken (known Gradio bug #10250).
Instead of trying to redirect to ?__theme=light, mirror all light
mode theme values into their _dark counterparts so dark mode looks
identical to light mode.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

app.py

@@ -768,20 +768,39 @@ textarea, input[type="text"] {
 
 FORCE_LIGHT = '<script>if(!location.search.includes("__theme=light")){const u=new URL(location);u.searchParams.set("__theme","light");location.replace(u)}</script>'
 
+_LIGHT = {
+    "button_primary_background_fill": "#63348d",
+    "button_primary_background_fill_hover": "#4a2769",
+    "button_primary_text_color": "#ffffff",
+    "block_background_fill": "#f3f0f7",
+    "block_border_color": "#ded9f4",
+    "body_background_fill": "#ffffff",
+    "body_text_color": "#1a1a2e",
+    "block_label_text_color": "#63348d",
+    "block_title_text_color": "#63348d",
+    "background_fill_primary": "#ffffff",
+    "background_fill_secondary": "#f3f0f7",
+    "input_background_fill": "#ffffff",
+    "input_background_fill_focus": "#ffffff",
+    "input_border_color": "#ded9f4",
+    "input_border_color_focus": "#63348d",
+    "input_placeholder_color": "#888888",
+    "border_color_primary": "#ded9f4",
+    "border_color_accent": "#63348d",
+    "panel_background_fill": "#f3f0f7",
+    "shadow_drop": "rgba(0,0,0,0.05) 0px 1px 2px 0px",
+    "block_shadow": "none",
+}
+# Mirror every light value into _dark so dark mode looks identical
+_ALL = {}
+for k, v in _LIGHT.items():
+    _ALL[k] = v
+    _ALL[k + "_dark"] = v
+
 THEME = gr.themes.Soft(
     primary_hue="purple",
     font=gr.themes.GoogleFont("Inter"),
-).set(
-    button_primary_background_fill="#63348d",
-    button_primary_background_fill_hover="#4a2769",
-    button_primary_text_color="#ffffff",
-    block_background_fill="#f3f0f7",
-    block_border_color="#ded9f4",
-    body_background_fill="#ffffff",
-    block_label_text_color="#63348d",
-    block_title_text_color="#63348d",
-    body_text_color="#1a1a2e",
-)
+).set(**_ALL)
 
 with gr.Blocks(title="Embedding Explorer", theme=THEME, css=CSS, head=FORCE_LIGHT) as demo: