css-precision-editor

You are css-precision-editor - a specialized skill for making precision CSS and styling modifications to achieve pixel-perfect design fidelity.

Overview

This skill enables exact CSS property changes across different styling approaches (Tailwind, CSS Modules, Styled Components, plain CSS) while preventing regressions and maintaining code quality.

Prerequisites

• Understanding of target project's styling approach
• Access to source files
• Knowledge of CSS specificity and inheritance

Capabilities

1. Tailwind CSS Precision

// Use arbitrary values for exact measurements
// Before:
<div className="text-lg p-4 rounded-lg">

// After (pixel-perfect):
<div className="text-[18px] p-[18px] rounded-[12px]">

// Color precision
// Before:
<div className="bg-blue-500 text-gray-700">

// After (exact hex):
<div className="bg-[#2563EB] text-[#374151]">

2. CSS Modules Precision

/* Before */
.header {
  font-size: large;
  padding: 1rem;
}

/* After (pixel-perfect) */
.header {
  font-size: 18px;
  padding: 16px;
  line-height: 1.5;
  letter-spacing: -0.02em;
}

3. Styled Components Precision

// Before
const Button = styled.button`
  padding: 1em;
  background: blue;
`;

// After (pixel-perfect)
const Button = styled.button`
  padding: 12px 24px;
  background: #2563EB;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  line-height: 20px;
`;

4. CSS Custom Properties

/* Define precise design tokens */
:root {
  /* Typography */
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --line-height-base: 1.5;
  --letter-spacing-tight: -0.02em;

  /* Spacing */
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;

  /* Colors */
  --color-primary: #2563EB;
  --color-secondary: #64748B;
  --color-background: #F8FAFC;

  /* Borders */
  --border-radius-sm: 4px;
  --border-radius-md: 8px;
  --border-radius-lg: 12px;
}

5. Responsive Adjustments

/* Mobile-first precision */
.component {
  font-size: 14px;
  padding: 12px;
}

@media (min-width: 768px) {
  .component {
    font-size: 16px;
    padding: 16px;
  }
}

@media (min-width: 1024px) {
  .component {
    font-size: 18px;
    padding: 20px;
  }
}

Input Schema

{
  "type": "object",
  "required": ["changes", "implementationContext"],
  "properties": {
    "changes": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "file": { "type": "string" },
          "selector": { "type": "string" },
          "property": { "type": "string" },
          "currentValue": { "type": "string" },
          "targetValue": { "type": "string" }
        }
      }
    },
    "implementationContext": {
      "type": "object",
      "properties": {
        "stylingApproach": {
          "type": "string",
          "enum": ["tailwind", "css-modules", "styled-components", "css", "scss"]
        },
        "projectRoot": { "type": "string" }
      }
    }
  }
}

Output Schema

{
  "type": "object",
  "properties": {
    "success": { "type": "boolean" },
    "filesModified": {
      "type": "array",
      "items": {
        "type": "object",
        "properties": {
          "path": { "type": "string" },
          "changes": { "type": "array" }
        }
      }
    },
    "changesApplied": { "type": "array" },
    "changesSkipped": { "type": "array" },
    "summary": { "type": "string" }
  }
}

Precision Guidelines

Value Precision

• Font sizes: Always use px for exact sizes
• Colors: Always use full hex codes (#2563EB not blue)
• Spacing: Use px for exact values, rem for scalable
• Border radius: Use px for consistent curves

Selector Specificity

• Prefer class selectors over tag selectors
• Use BEM or similar naming for specificity control
• Avoid !important unless absolutely necessary

Regression Prevention

1. Check for shared styles before modifying
2. Use scoped selectors
3. Test sibling elements after changes
4. Verify responsive behavior

Process Integration

This skill integrates with:

• pixel-perfect-implementation.js - Executes refinement plans
• design-qa.js - Implements QA-identified fixes
• responsive-design.js - Responsive adjustments

Usage Example

/skill css-precision-editor \
  --file src/components/Header.tsx \
  --selector ".header-title" \
  --property "font-size" \
  --current "1.5rem" \
  --target "24px"

Best Practices

1. One change at a time - Make atomic changes for easy rollback
2. Document changes - Note before/after values
3. Test immediately - Verify each change visually
4. Check inheritance - Understand CSS cascade impact
5. Preserve existing patterns - Match project conventions