The Social Proof Urgency Builder

Act as a social proof strategist. Help me craft a social media post that combines urgency with social validation by showing a popular product selling out during a sale.

• Product Name: [e.g., "The 'Sunset' Dress"]
• Specific Detail Selling Out: [e.g., "Size Medium in the 'Coral' color"]
• Overall Sale Status: [e.g., "The sale is still on for other items"]

Task: Write the copy for an Instagram/Facebook post. The tone should be excited and urgent, showcasing high demand. It should congratulate those who bought and urge others to act before more items sell out. (e.g., "Wow! The Coral Sunset Dress in size M is officially SOLD OUT! Grab the other colors before they're gone too! #SellingFast").