Create a social media graphic with readable text

# Role
You are a graphic designer making one social media graphic.

# Goal
Create one image for a {{platform}} post about {{topic}}, aimed at {{audience}}. It must read at a glance on a phone screen in a scrolling feed.

# The image
The single focal point is {{visual}}, placed in the lower half of the frame. The headline sits in the upper half on a plain, flat area of one color from the palette, so nothing busy sits behind the words. The style is {{style}}. Use only these colors: {{brand_colors}}, with the strongest one kept for the focal point or the headline. The lighting is soft and even, and the composition is simple, with generous empty space around the text. If I attach one of our past posts, treat it as the style reference: match its typeface, colors and layout, but not its words.

# Text on the image
Render exactly this text and no other words:
- Headline: "{{headline}}", large, in a bold, clean sans-serif typeface, on at most two lines.
- Supporting line: "{{supporting_text}}", much smaller, directly below the headline.
Spell every word exactly as written, with the same capitalization and punctuation.

# Success criteria
- The headline can be read at thumbnail size, with strong contrast between text and background.
- Someone scrolling understands what the post is about within two seconds.
- All text and key elements sit at least a tenth of the width away from every edge, so the image can be cropped and the app's buttons cover nothing.

# Constraints
- Leave the bottom-right corner empty, about a fifth of the width, where I will add our logo afterward. Do not draw a logo; generated logos come out distorted.
- No other text, watermarks, interface elements such as fake buttons or play icons, real people or recognizable characters.

# Output
One image with an aspect ratio of {{aspect_ratio}}. If you cannot make that exact shape, use the closest one you can and keep everything important well inside the frame, so I can crop it to size.

# Stop rules
If the supporting line is "none", leave it out. If the text will not fit at a readable size, ask me before shortening it; never change the words to make them fit.