CSS (Cascading Style Sheets) is the language used to design, format, and control the visual presentation of HTML web documents. CSS manages layout positioning, colors, typography, spacing, responsive viewports, and visual effects.
CSS separates visual design presentation from HTML document structure:
/* CSS ruleset styling page elements */
body {
background-color: #0f172a;
color: #f8fafc;
font-family: system-ui, sans-serif;
}
Core benefits of CSS:
flowchart LR
A["HTML (Document Structure)"] --> B["Browser Rendering Engine"]
C["CSS (Visual Presentation & Layout)"] --> B
D["JavaScript (Dynamic Behavior)"] --> B
B --> E["Visual Web Page"]
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>CSS Introduction Example</title>
<style>
/* Internal CSS Stylesheet */
.card {
background-color: #1e293b;
border-left: 4px solid #38bdf8;
padding: 1.5rem;
border-radius: 8px;
max-width: 500px;
}
.card-title {
color: #38bdf8;
margin-top: 0;
}
</style>
</head>
<body style="background-color: #0f172a; color: #f8fafc; font-family: system-ui, sans-serif; padding: 2rem;">
<div class="card">
<h2 class="card-title">Welcome to CSS Styling</h2>
<p>CSS allows developers to transform plain HTML tags into modern, visually polished user interfaces.</p>
</div>
</body>
</html>
.css files linked via <link rel="stylesheet"> to enable browser caching.style="..." attributes to a minimum to maintain clean code separation.:root variables (--primary-color: #38bdf8;).Create a CSS rule targeting a .banner class that sets a dark background color (#1e293b), rounded corners (8px), and padding (1rem)!
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