Design a sleek, modern icon symbolizing a Stage Development Environment. The icon should include elements like a layered server stack or a data center, representing the deployment process, alongside a progress bar or upward arrow, symbolizing pre-production readiness. Incorporate subtle representations of cloud infrastructure or an application window to indicate the near-final testing stage. Use a dark background with vibrant colors like teal, blue, and orange to highlight key elements. The design should convey stability, preparation, and readiness for production, with a clean, polished appearance.