Turn One Idea Into a Full Newsletter Issue

You've got the seed of next week's issue and nothing else. This grows that single idea into a full read: a working subject line, an opening hook, and a body that stays on one thread rather than sprawling. Good for the Sunday-night writer staring at a one-line note, wondering how it becomes 800 words people finish.

I have a single idea for my next newsletter issue but I need to expand it into a complete, satisfying read.

My core idea: {CORE_IDEA}
Newsletter name: {NEWSLETTER_NAME}
Approximate word count target: {WORD_COUNT}
Tone: {TONE}

Using the one-idea-per-issue principle, expand this idea into a full issue. Structure your output as:
1. A working subject line
2. An opening hook (first 3 sentences only: make them irresistible)
3. The main body broken into 2 to 3 logical sections with subheadings
4. One concrete example, story, or data point that illustrates the idea
5. A clear takeaway or actionable close
6. A call to action

Do not pad the issue with unrelated content. Every paragraph must serve the single idea.