Angles are used with Aural CSS
properties to indicate the location of sounds/events relative to the
listener. An angle value is given using a number, followed by the angle
unit (listed below.) Angle values may be positive or negative (numbers
are prefixed with a plus or minus sign ("+"/"-".) Negative angle values
are of opposite rotation to the reference positive direction. If an
angle value is larger than one full rotation, the computed value is the
angle remainder from the reference zero angle axis.
Angle Units in CSS
Description: Degrees. Divides a circle in 360 equal parts.
Description: Grads. A 90 degree, right-angle
represents 100 grads. A full circle would be 400 equal grads.
Description: Radians. Divides a circle in 2*PI units.