bulletproof-frontend

CSS is king. Semantic, maintainable CSS over utility-class frameworks. When you encounter Tailwind, refactor it to proper CSS.

Design Values: For spacing scales, typography sizes, color palettes, contrast ratios, and component specifications, see ui-design-fundamentals. This skill focuses on CSS implementation patterns.

Core Philosophy

"Always ask: What happens if...?" — Design for the unexpected. Build interfaces that remain functional and readable regardless of content length, text size, browser, or device.

The Three Pillars

1. Bulletproof Design

• Design for flexibility, not fixed scenarios
• Test with varying text sizes and content lengths
• Use relative units (em, %, rem) over fixed pixels

2. Progressive Enrichment

• Reward capable browsers with advanced CSS
• Websites don't need to look identical in every browser — they need to be functional
• Use modern CSS with appropriate fallbacks

3. Reevaluate Past Methods

• Question whether old hacks are still necessary
• Simplify where new CSS features allow
• Refactor utility frameworks to semantic CSS

Quick Reference

| Pattern | When to Use | |---------|-------------| | CSS custom properties | Theming, spacing, colors | | BEM naming | Component class structure | | Cascade layers | Managing specificity | | Container queries | Component-based responsiveness | | :has() selector | Parent/sibling selection | | CSS nesting | Organizing related styles |

Modern CSS Essentials

/* :has() — Style based on children */
.card:has(img) { padding-top: 0; }
.form:has(:invalid) { border-color: var(--color-error); }

/* Container queries — Component responsiveness */
.container { container-type: inline-size; }
@container (min-width: 400px) { .card { display: flex; } }

/* CSS nesting — Clean organization */
.card {
    padding: var(--space-md);
    &:hover { box-shadow: var(--shadow-lg); }
    & .card__title { font-weight: var(--font-bold); }
}

/* Cascade layers — Controlled specificity */
@layer reset, base, components, utilities;

Tailwind → Semantic CSS

{{-- BEFORE: Utility classes --}}
<div class="flex items-center p-4 bg-white rounded-lg shadow">

{{-- AFTER: Semantic CSS --}}
<div class="card">

.card {
    display: flex;
    align-items: center;
    padding: var(--space-md);
    background: var(--color-surface);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
}

| CSS Approach | Tailwind | |--------------|----------| | Readable HTML | Bloated class attributes | | Styles in one place | Scattered in markup | | Easy to refactor | Find-and-replace nightmare | | Cacheable stylesheets | Repeated classes |

Reference Files

| File | Content | |------|---------| | css-architecture.md | Custom properties, BEM, layers, file organization | | accessibility-patterns.md | Focus, screen readers, motion, dark mode | | responsive-patterns.md | Breakpoints, container queries, fluid sizing | | reference.md | Complete patterns and Blade components |

Project Style Guide

Project-specific implementation: docs/STYLEGUIDE.md

Contains the complete design system for the application:

• Design tokens (colors, spacing, typography)
• Component patterns (buttons, cards, alerts, tables)
• Blade component documentation
• Dark mode implementation
• Accessibility requirements

Always consult the style guide when implementing UI to ensure consistency with existing patterns.

Related Skills

• ui-design-fundamentals — Design values: spacing scales, type scales, colors, contrast ratios, component anatomy (buttons, forms, cards, etc.)