Basic CSS concepts

1) A style sheet is composed of rules.
2) Rules are composed of selectors and declarations.
3) declarations are composed of attributes and values.
4) The value can be a keyword, length, color, String, integer, real type, or Uri.
5) Em brightness is best used for screen layout. Absolute Measurement Units in inches and centimeters are more suitable for printing la S. pixel units are used when users do not require the font size.
6) jitter is used to simulate unknown colors by mixing known colors.
7) RGB is an overlay color.
8) the hexadecimal color is another way to represent the RGB color.
9) Short hexadecimal notation is a Web security color method.
10) URI is used to include style sheets and background images in CSS.
11) You can use the <style> element to embed a style sheet into an HTML file.
12) a style sheet can exist in an independent document. You can use the <link> element to link it to an HTML document or use the @ import rule to import it to another style sheet.
13) You can use the style attribute to inline include styles in HTML elements.