CSS Units:
CSS has several different types of units that can be used to define lengths and sizes in your stylesheets. Here are some of the most commonly used units:
- px (pixels): A pixel is the smallest unit of measurement in CSS. It is used to define precise sizes and positions on the screen.
- em: An em is a relative unit of measurement that is based on the font size of the parent element. For example, if the font size of the parent element is 16 pixels, then 1em is equal to 16 pixels.
- rem: A rem is also a relative unit of measurement, but it is based on the font size of the root element (usually the <html> tag). This makes it easier to create scalable designs that are independent of the font sizes set by the user.
- % (percent): A percentage is a relative unit of measurement that is based on the size of the parent element. For example, if the parent element is 200 pixels wide, and you set the width of a child element to 50%, then the child element will be 100 pixels wide.
- vw and vh: Viewport width (vw) and viewport height (vh) are relative units of measurement that are based on the size of the browser window. For example, 1vw is equal to 1% of the width of the viewport.
- pt (points): A point is a unit of measurement that is commonly used in print design. It is equal to 1/72 of an inch.
- cm, mm, in: These units are used to define lengths in centimeters, millimeters, and inches, respectively. They are commonly used in print design.
- ch: The width of the “0” (zero) character in the font being used. This is useful for aligning text based on character width.
- ex: The height of the lowercase “x” character in the font being used. This is useful for aligning text based on character height.
Each unit has its own strengths and weaknesses, and the choice of which unit to use depends on the specific requirements of your design.