Update main.py

main.py

@@ -396,17 +396,32 @@ def get_user_greeting(profile: gr.OAuthProfile | None):
 # BUILD UI
 # =========================
 
-OVERVIEW_MD = """
-## VizWiz Object Localization Challenge
-
-Submit your model predictions and get scored automatically against hidden ground-truth annotations.
-
-- 📤 **Submit Predictions** — Upload your prediction JSON for Dev, Standard, or Challenge phases
-- 🏆 **Leaderboard** — View public rankings for the Standard phase
-- 📋 **My Submissions** — Track all your past submissions and scores
-
-> Log in with your HuggingFace account to submit predictions.
-"""
+CHALLENGES = [
+    {
+        "id": "object-localization",
+        "title": "Object Localization",
+        "emoji": "🎯",
+        "description": "Detect and segment objects in images taken by blind photographers. Submit bounding box and instance segmentation predictions evaluated with pycocotools.",
+        "metrics": "bbox_mAP · bbox_AP50 · segm_mAP · segm_AP50",
+        "active": True,
+    },
+    {
+        "id": "vqa",
+        "title": "Visual Question Answering",
+        "emoji": "🤔",
+        "description": "Answer open-ended questions about images taken by blind users. Models are evaluated on answer accuracy and relevance.",
+        "metrics": "Coming soon",
+        "active": False,
+    },
+    {
+        "id": "answer-grounding",
+        "title": "Answer Grounding",
+        "emoji": "📍",
+        "description": "Ground free-form answers to visual regions in images taken by blind photographers.",
+        "metrics": "Coming soon",
+        "active": False,
+    },
+]
 
 EVAL_DETAILS_MD = """
 ### How is the Score Calculated?
@@ -441,19 +456,126 @@ Your JSON file must be a **list of annotation objects**, each containing:
 ```
 """
 
-with gr.Blocks(title="VizWiz Benchmark Arena", theme=gr.themes.Soft()) as demo:
+OBJ_LOC_OVERVIEW_MD = """
+## 🎯 Object Localization Challenge
+
+Submit your model predictions and get scored automatically against hidden ground-truth annotations.
+
+- 📤 **Submit Predictions** — Upload your prediction JSON for Dev, Standard, or Challenge phases
+- 🏆 **Leaderboard** — View public rankings for the Standard phase
+- 📋 **My Submissions** — Track all your past submissions and scores
+"""
 
-    gr.Markdown("# 🏆 VizWiz Benchmark Arena")
+# Build challenge cards HTML for landing page
+def _build_challenge_cards_html() -> str:
+    cards = ""
+    for c in CHALLENGES:
+        if c["active"]:
+            card = f"""
+            <div style="
+                border: 2px solid #2563eb;
+                border-radius: 12px;
+                padding: 24px;
+                background: #f0f7ff;
+                flex: 1;
+                min-width: 220px;
+                max-width: 340px;
+            ">
+                <div style="font-size: 2.5rem; margin-bottom: 8px;">{c['emoji']}</div>
+                <h3 style="margin: 0 0 8px 0; color: #1e40af; font-size: 1.1rem;">{c['title']}</h3>
+                <p style="margin: 0 0 12px 0; color: #374151; font-size: 0.9rem; line-height: 1.5;">{c['description']}</p>
+                <div style="
+                    background: #dbeafe;
+                    border-radius: 6px;
+                    padding: 6px 10px;
+                    font-size: 0.78rem;
+                    color: #1d4ed8;
+                    font-family: monospace;
+                ">📊 {c['metrics']}</div>
+                <div style="margin-top: 14px;">
+                    <span style="
+                        background: #2563eb;
+                        color: white;
+                        padding: 6px 14px;
+                        border-radius: 6px;
+                        font-size: 0.85rem;
+                        font-weight: 600;
+                    ">✅ Active — scroll down to participate</span>
+                </div>
+            </div>"""
+        else:
+            card = f"""
+            <div style="
+                border: 2px solid #d1d5db;
+                border-radius: 12px;
+                padding: 24px;
+                background: #f9fafb;
+                flex: 1;
+                min-width: 220px;
+                max-width: 340px;
+                opacity: 0.65;
+            ">
+                <div style="font-size: 2.5rem; margin-bottom: 8px;">{c['emoji']}</div>
+                <h3 style="margin: 0 0 8px 0; color: #6b7280; font-size: 1.1rem;">{c['title']}</h3>
+                <p style="margin: 0 0 12px 0; color: #9ca3af; font-size: 0.9rem; line-height: 1.5;">{c['description']}</p>
+                <div style="
+                    background: #f3f4f6;
+                    border-radius: 6px;
+                    padding: 6px 10px;
+                    font-size: 0.78rem;
+                    color: #9ca3af;
+                    font-family: monospace;
+                ">📊 {c['metrics']}</div>
+                <div style="margin-top: 14px;">
+                    <span style="
+                        background: #e5e7eb;
+                        color: #6b7280;
+                        padding: 6px 14px;
+                        border-radius: 6px;
+                        font-size: 0.85rem;
+                        font-weight: 600;
+                    ">🔒 Coming Soon</span>
+                </div>
+            </div>"""
+        cards += card
+
+    return f"""
+    <div style="display: flex; gap: 20px; flex-wrap: wrap; margin: 16px 0;">
+        {cards}
+    </div>
+    """
+
+
+with gr.Blocks(title="VizWiz Benchmark Arena", theme=gr.themes.Soft()) as demo:
 
+    # ── HEADER ───────────────────────────────────────────────────────────
     with gr.Row():
-        with gr.Column(scale=4):
-            gr.Markdown(OVERVIEW_MD)
-        with gr.Column(scale=1):
+        with gr.Column(scale=5):
+            gr.Markdown("# 🏆 VizWiz Benchmark Arena")
+            gr.Markdown(
+                "An automated evaluation platform for VizWiz challenges — "
+                "datasets collected from blind photographers using a smartphone app."
+            )
+        with gr.Column(scale=1, min_width=160):
             login_btn = gr.LoginButton(size="lg")
-            user_greeting = gr.Markdown("👋 Log in with HuggingFace to submit.")
+            user_greeting = gr.Markdown("👋 Log in to submit.")
+
+    gr.Markdown("---")
+
+    # ── LANDING PAGE ─────────────────────────────────────────────────────
+    gr.Markdown("## Challenges")
+    gr.Markdown(
+        "Select a challenge below to view its leaderboard, submit predictions, "
+        "and track your results. New challenges will be added over time."
+    )
+    gr.HTML(_build_challenge_cards_html())
 
     gr.Markdown("---")
 
+    # ── OBJECT LOCALIZATION CHALLENGE ────────────────────────────────────
+    gr.Markdown("## 🎯 Object Localization")
+    gr.Markdown(OBJ_LOC_OVERVIEW_MD)
+
     with gr.Tabs():
 
         # ── LEADERBOARD TAB ──────────────────────────────────────────────