Length, Size Types and URL Values
Explore how to specify sizes in CSS using units like pixels, ems, and percentages, and understand their effects on layout and cross-platform compatibility. Learn how to apply URL values for setting background images. This lesson helps you accurately control element dimensions and backgrounds for better web page design.
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When designing the layout of a page, you often need to specify sizes, such as the width or height of a box, top and bottom margins of paragraphs, and so on.
To indicate size, CSS offers a number of type size options including:
- pixels
- points
- picas
- inches
- centimeters
- millimeters
- em-heights
- ex heights
- percentages
When you define a style property that specifies a size or length value, you always need to specify the unit of measure as well.
The above point is shown in the example below:
The only value that does not need a unit of measure is zero, for it is exactly the same independent of the unit used to calculate it.
The table below summarizes the size type options:
Size type options
Logical units ( ...