Prompt for a social media cover with your brand

Act as a brand identity designer and an expert in prompts for image generators.

From my brand details, write me a prompt in English to generate a cover image (banner) for social media, consistent with my color palette and my message.

My brand or business: [DESCRIBE WHAT YOU DO IN ONE SENTENCE]
Platform and size: [E.G. LinkedIn 1584x396, Facebook 820x312, X 1500x500, YouTube 2560x1440]
My brand colors: [E.G. #EC4899 magenta, #7C3AED purple, dark background]
Message or feeling I want to convey: [E.G. innovative and approachable / luxurious and minimal / warm and human]
Must-have elements (optional): [E.G. my logo on the left, space for text on the right]

Give me:
1. A detailed main prompt in English: visual style, composition, exact color palette, lighting, and "no text, no logos, high resolution, banner composition" (text and logo get added afterward, not inside the generated image).
2. 2 variations (different composition or style) in case the first one doesn't fit.
3. Where to leave negative space based on the platform I chose, so text or a logo won't cover anything important when I add it later.
4. A short tip so the cover looks professional and not generic.

Rules: use ONLY the colors and message I gave you, without inventing brand elements I didn't mention. Clear prompt, comma-separated.