- Fix 6 overlapping widget bugs in StepHeader (title/desc, btn/icon,
run/rerun) with proper 5-column grid layout
- Merge run/rerun buttons into single _action_btn with state-driven text
- Fix DARK_CARD NameError (undefined import → STEP_CARD_BG)
- Replace fragile vertical connector lines with full-width dividers
- Add panel.grid_columnconfigure(0, weight=1) for horizontal scaling
- Unify button text across all states (▶ pending/disabled, ↻ retry)
- Tighten padding and reduce whitespace between steps
- Replace Segoe UI with Roboto for cross-platform compatibility
- Increase font sizes for better readability (9→11, 11→12, 14→15)
- Update dark theme to VS Code-like colors (#1E1E1E bg)
- Brighten accent colors and improve contrast ratios
- Fix StepHeader: number circle background, status icon positioning
- Enlarge accent bar (4→5px) and buttons (28→32px)
- Simplify status text (Completed → Done)
- Improve connector line sizing and alignment