The class of an element is unique within a page, so the class selector is used to select one unique element!

To select an element with a specific id, write .. character, followed by the id of the element.

The id selector uses the id attribute of an HTML element to select a specific element

To group selectors, separate each selector with a …

It will be better to group the selectors, to minimize the code.

The grouping selector selects all the HTML elements with the same style definitions

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inserting a style sheet

you can change the look of an entire website by changing just one file!

Each HTML page must include a reference to the external style sheet file inside the element …. , inside the head section

The external .css file can contain HTML tags

may be used if one single HTML page has a unique style

The … is defined inside the <style>

may be used to apply a unique style for a single element

If some properties have been defined for the same selector (element) in different style sheets, the value from the last read style sheet will be used

If the internal style is defined after the link to the external style sheet, the elements will apply external style

if the internal style is defined before the link to the external style sheet, the elements will apply the external style