<h2>Why Clean CSS Matters</h2><p>CSS is deceptively simple to write and <strong>incredibly hard</strong> to maintain. A codebase with messy CSS becomes a minefield where changing one rule breaks three others.</p><h3>Naming Conventions</h3><p>Adopt a methodology like <em>BEM</em> (Block Element Modifier):</p><pre><code>.card { }\n.card__title { }\n.card__title--highlighted { }</code></pre><h3>Avoid These Anti-Patterns</h3><ul><li>Using <code>!important</code> as a fix for specificity issues</li><li>Deeply nested selectors (more than 3 levels)</li><li>Magic numbers like <code>margin-top: 37px</code></li><li>Styling IDs instead of classes</li></ul><h3>Modern CSS Features Worth Using</h3><ol><li><strong>CSS Custom Properties</strong> for theming and consistency</li><li><strong>CSS Grid</strong> for two-dimensional layouts</li><li><strong>Container queries</strong> for truly reusable components</li><li><strong><code>:has()</code> selector</strong> for parent-based styling</li></ol><blockquote><p>The best CSS is the CSS you don't have to write. Utility frameworks like <strong>Tailwind CSS</strong> eliminate entire categories of maintenance burden.</p></blockquote><hr><p>Remember: every line of CSS you write is a line someone else has to understand later.</p>