# Plan: Split index.md into multiple files

## Current state
- ~4200 lines, 5 sessions + intro/outro
- Shared: frontmatter, styles, intro slides (title, about, schedule, survey, overview)
- Per-session: actual content

## Proposed structure

```
slides/
├── _frontmatter.yml      # shared marp config
├── _styles.md            # shared CSS
├── _intro.md             # title, about, schedule, survey, overview
├── termin-1.md           # Session 1 content
├── termin-2.md           # Session 2 content
├── termin-3.md           # Session 3 content
├── termin-4.md           # Session 4 content
├── termin-5.md           # TBA session
└── _outro.md             # Q&A, license
```

## Makefile targets

```makefile
# Shared parts
HEADER = slides/_frontmatter.yml slides/_styles.md
INTRO  = slides/_intro.md
OUTRO  = slides/_outro.md

# Build single termin (intro + content + outro)
build-termin-%:
	cat $(HEADER) $(INTRO) slides/termin-$*.md $(OUTRO) > build/termin-$*.md
	marp build/termin-$*.md -o build/termin-$*.html

# Dev mode for single termin
dev-%:
	cat $(HEADER) $(INTRO) slides/termin-$*.md $(OUTRO) > build/.dev.md
	PORT=1312 marp --server build/

# Build all
build-all:
	cat $(HEADER) $(INTRO) slides/termin-*.md $(OUTRO) > build/all.md
	marp build/all.md -o build/all.html
```

## Usage

```bash
make dev-1          # preview termin 1
make dev-3          # preview termin 3
make build-termin-2 # build termin 2
make build-all      # build everything
```

## Trade-offs
- Requires intermediate file generation
- Can't use `marp --watch` directly on source (need wrapper)
- But: clean separation, single source of truth for styles

## Status
- [ ] Learn Marp/Marpit in depth first
- [ ] Implement split
- [ ] Update Makefile
- [ ] Test all targets