style: enhance Matplotlib chart with premium dark background, value labels, and tight margins

app/services/export_service.py

@@ -102,16 +102,43 @@ REQUIREMENTS:
             elif s >= 40: colors.append('#3b82f6') # Blue
             else: colors.append('#10b981')         # Emerald
 
-        plt.figure(figsize=(10, 6))
-        plt.style.use('dark_background')
-        bars = plt.barh(descriptions, scores, color=colors)
-        plt.xlabel('Importance Score (%)')
-        plt.title('Identified Research Gaps - Priority Map')
-        plt.grid(axis='x', linestyle='--', alpha=0.3)
-        plt.tight_layout()
+        # Setup modern dark style with baked-in slate background
+        fig, ax = plt.subplots(figsize=(10, 6), facecolor='#0b0f19')
+        ax.set_facecolor('#0b0f19')
+        
+        # Plot horizontal bars
+        bars = ax.barh(descriptions, scores, color=colors, height=0.55)
+        
+        # Customize labels & title
+        ax.set_xlabel('Importance Score (%)', color='#94a3b8', fontsize=11, fontweight='bold', labelpad=10)
+        ax.set_title('Identified Research Gaps - Priority Map', color='#f8fafc', fontsize=14, fontweight='bold', pad=20)
+        
+        # Grid and spines configuration
+        ax.grid(axis='x', linestyle='--', alpha=0.15, color='#94a3b8')
+        ax.set_axisbelow(True)
+        
+        # Style ticks and text color
+        ax.tick_params(colors='#94a3b8', labelsize=10)
+        for spine in ax.spines.values():
+            spine.set_color('#1e293b')
+            
+        # Add beautiful value labels next to the bars
+        for bar in bars:
+            width = bar.get_width()
+            ax.text(
+                width + 1.5, 
+                bar.get_y() + bar.get_height()/2, 
+                f'{int(width)}%', 
+                va='center', 
+                ha='left', 
+                color='#f8fafc', 
+                fontweight='bold',
+                fontsize=9
+            )
 
         os.makedirs(os.path.dirname(output_path), exist_ok=True)
-        plt.savefig(output_path, transparent=True)
+        # Save with explicit facecolor to bake the premium dark background into the PNG
+        plt.savefig(output_path, facecolor='#0b0f19', edgecolor='none', bbox_inches='tight', dpi=150)
         plt.close()
         
         return output_path