Code Reference

Getting Started with CSS

CSS · Reference cheat sheet

Getting Started with CSS

CSS · Reference cheat sheet


📋 Overview

CSS (Cascading Style Sheets) controls how HTML looks: colors, spacing, layout, and responsive behavior. You select elements and declare properties inside rules.

🔧 Core concepts

IdeaMeaning
Ruleselector \{ property: value; \}
SelectorWhich elements the rule targets
PropertyWhat to change (color, margin, …)
CascadeHow conflicting rules are resolved
StylesheetA .css file or <style> block

Link CSS from HTML with <link rel="stylesheet" href="styles.css" />.

💡 Examples

Inline link in HTML:

<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="utf-8" />
    <title>CSS demo</title>
    <link rel="stylesheet" href="styles.css" />
  </head>
  <body>
    <h1 class="title">Hello, CSS</h1>
  </body>
</html>

styles.css:

body {
  font-family: system-ui, sans-serif;
  margin: 2rem;
  background: #f6f7f9;
}

.title {
  color: #0f172a;
  font-size: 2rem;
}

Quick experiment in a <style> tag:

<style>
  p {
    line-height: 1.5;
  }
</style>

⚠️ Pitfalls

  • Typos in property names fail silently (nothing happens).
  • Specificity wars — prefer simple class selectors while learning.
  • Browser default styles differ; a small reset/normalize helps later.
  • Inline style="" attributes override stylesheets and are hard to maintain.

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