The letter-spacing property in CSS uses the standard CSS absolute units of measurement, such as inches (in) and points (pt) and relative values such as em (em) and percent (%). For more information ...

About the space-start value in this definition, I have proposed to change it to space-first in the following issue: [css-text-4] Propose 'text-spacing: space-first' (trim-start-except-first-line) as a ...