Cascade and Rule Declarations

Cascade

Styles passing from higher to lower hierarchy levels.

Cascade Rules

Cascade Rules p57:

1. Find all declarations that apply to each element and property
2. Sort by order and weight
3. Sort by specificity
4. Sort by order

Weight of declaration

Define a rule as important using the exclamation point. Marking a tag as important will override the cascade.

p {color:red !important; font-size:12pt;}

Rule Declarations

Declarations are made up of a property and value.

Example:

p {color:red;}

color = property and red = value

Values fall into three main types:

1. Words
2. Numerical values
3. Color values

Numerical values

Use to decribe the "distance" or height, width, depth, length, etc. for many values. p61

Two main groups of numerical values:

1. Absolute
2. Relative

Absolute value describes a real distance. Relative value compared to another.

Absolute value chart:

Absolute Value	Unit Abbreviation
Inches	in
Centimeters	cm
Millimeters	mm
Points	pt
Picas	pc
Pixels	px

Relative value chart:

Relative Value	Unit Abbreviation	Note
Em	em	Width of character in a font.
Ex	ex	Equivalent to the x-height of the given font.
Percentage	%

Color Values

Hexadecimal format

#RRGGBB

Percentages format

R%, G%, B% 

Back to Cascade Style Sheets