| name | better-interface |
| description | Design engineering principles for making TUI interfaces feel polished. Use when building Textual widgets, reviewing TUI code, implementing transitions, focus states, alignment, spacing, or any visual detail work. Triggers on TUI polish, design details, "make it feel better", "feels off", layout alignment, color consistency, responsive sizing. |
Details that make TUI interfaces feel better
Great TUIs rarely come from a single thing. It's a collection of small details that compound into a professional experience. Apply these principles when building or reviewing Textual/terminal UI code.
Quick Reference
| Category | When to Use |
|---|
| Layout | Alignment, spacing, responsive sizing, content regions |
| Color | Palette consistency, contrast, semantic color usage |
| Interaction | Focus management, key hints, modal flow, feedback |
| Typography | Text truncation, wrapping, Unicode, monospace alignment |
Core Principles
1. Consistent Spacing
Use a spacing scale (1, 2, 4 cells). Mismatched padding between related
elements is the most common thing that makes TUIs feel off. Textual's
padding and margin CSS properties use cell units.
2. Optical Alignment Over Grid Alignment
When geometric centering looks wrong in a terminal, adjust optically.
Asymmetric Unicode characters (arrows, bullets) and mixed-width content
need manual nudging. A centered title above left-aligned content often
needs 1 cell of left padding removed.
3. Color Hierarchy
Use 3-4 color tiers consistently:
- Primary: key actions, active focus (bright, saturated)
- Secondary: labels, metadata (dimmed)
- Muted: borders, separators (very dim)
- Danger/Success: semantic states only (red/green)
Never use bright colors for passive elements. Reserve saturation for
things the user needs to notice.
4. Focus is Sacred
The focused widget must be visually distinct at a glance. Use border
color changes, not just cursor position. A user glancing at the screen
should instantly know where input will go.
5. Responsive Layout
TUI must work at 80x24 minimum. Use fr units and max-width/
min-width in Textual CSS to adapt. Content that overflows should
truncate with ellipsis, never wrap into garbage.
6. Feedback on Every Action
Every keypress that does something should produce visible feedback
within one frame. If an operation takes time, show a spinner or
status message immediately — don't let the user wonder if their
input was received.
7. Subtle Transitions
Textual supports CSS transitions. Use short durations (150-300ms)
for background color and opacity changes on hover/focus. Never
animate layout properties (width, height) — terminal reflow is
not smooth.
8. Border Consistency
Pick one border style and stick with it. tall for primary
containers, round for cards/modals, heavy for emphasis. Mixing
ascii, tall, round, and heavy in one screen looks
incoherent.
9. Key Hints
Always show available keys in a footer or status bar. Format as
key action pairs separated by thin spaces. Dim the keys relative
to the actions. Update hints contextually as focus moves.
10. Content Density
Terminal space is precious. Default to dense layouts. Use blank
lines only to separate logical groups, never for decoration.
Single-line headers over multi-line. Abbreviate labels when
the full form is obvious from context.
Common Mistakes
| Mistake | Fix |
|---|
| Inconsistent padding between similar widgets | Use a spacing constant |
| Bright colors on passive/decorative elements | Reserve bright for actions and focus |
| No visible focus indicator | Add border color or background change on focus |
| Content overflows and wraps badly | Set overflow: hidden with text-overflow: ellipsis |
| No key hints visible | Add contextual footer with available actions |
| Large empty regions at default size | Use fr units to distribute space |
| Mixed border styles in one view | Standardize on one style per element tier |
| No feedback on async operations | Show spinner/status immediately on action |
Review Checklist
Reference Files
