Web development
CSS Rules and the Box Model
Updated Oct 28, 2026
A CSS rule has a selector and declarations: p { color: navy; }. Link a stylesheet from the HTML head. The box model includes content, padding, border and margin. Font size and contrast affect readabil
What you’ll learn
Understand and practise css rules and the box model.
Explanation
A CSS rule has a selector and declarations: p { color: navy; }. Link a stylesheet from the HTML head. The box model includes content, padding, border and margin. Font size and contrast affect readability. Inspect the page to see which styles apply.
CSS មាន selector និង declarations។ Box model រួមមាន content, padding, border និង margin។ ជ្រើសពណ៌ និងទំហំអក្សរដែលងាយអាន។
Example
p { color: navy; margin: 1rem; } styles paragraphs.
Practice
Which space is outside the border?
Answer and explanation
Show answer / បង្ហាញចម្លើយ
Margin is outside the border; padding is inside it.
Quick recap
A CSS rule has a selector and declarations: p { color: navy; }.