The flag of Czechia consists of two horizontal stripes and a blue isosceles triangle. The aspect ratio of the flag is 2:3.

Colors:

1. White (top stripe): HEX #FFFFFF, RGB(255, 255, 255)
2. Red (bottom stripe): HEX #D7141A, RGB(215, 20, 26)
3. Blue (triangle): HEX #11457E, RGB(17, 69, 126)

Geometric properties and measurements:

1. The top white stripe and bottom red stripe are equal in height, each occupying half of the flag's total height.
2. The blue isosceles triangle has its base on the hoist side of the flag and extends to the midpoint of the flag's length.
3. The triangle's height is equal to the flag's height, and its base is equal to half of the flag's length.