Make API Integration card span full width

- Easy Invoice and Fork EasyInvoice in 2-column layout
- Build with API card below spans full width

Author: MantisClone

use-cases/checkout.mdx

@@ -99,43 +99,41 @@ Not sure which approach fits your needs? [See our detailed comparison of integra
 
     [View repository →](https://github.com/RequestNetwork/easy-invoice)
   </Card>
-  
-  <Card 
-    title="Build with API" 
-    icon="code"
-    href="/api-features/payouts"
-  >
-    **Full API integration**
-    
-    Build custom checkout experience using Request Network API directly.
-    
-    - Complete control over UX and flows
-    - Use payout endpoints for immediate payments
-    - Add platform fees and custom logic
-    
-    [Payout API docs →](/api-features/payouts)
-  </Card>
 </CardGroup>
 
+<Card 
+  title="Build with API" 
+  icon="code"
+  href="/api-features/payouts"
+>
+  **Full API integration**
+  
+  Build custom checkout experience using Request Network API directly.
+  
+  - Complete control over UX and flows
+  - Use payout endpoints for immediate payments
+  - Add platform fees and custom logic
+  
+  [Payout API docs →](/api-features/payouts)
+</Card>
+
 ## Developer Tools
 
-<CardGroup cols={1}>
-  <Card 
-    title="Payment Widget Button" 
-    icon="credit-card"
-    href="#"
-  >
-    **Pre-built React checkout component**
-    
-    Drop-in component for crypto payments—works with Easy Invoice Client IDs or direct API integration.
-    
-    - Wallet connection and payment processing included
-    - Fully customizable styling
-    - Compatible with all integration options above
-    
-    [View demo →](https://checkout.request.network)
-  </Card>
-</CardGroup>
+<Card 
+  title="Payment Widget Button" 
+  icon="credit-card"
+  href="#"
+>
+  **Pre-built React checkout component**
+  
+  Drop-in component for crypto payments—works with Easy Invoice Client IDs or direct API integration.
+  
+  - Wallet connection and payment processing included
+  - Fully customizable styling
+  - Compatible with all integration options above
+  
+  [View demo →](https://checkout.request.network)
+</Card>
 
 ## When to Use Checkout