The Color struct defines colours as a 0->1 float, it does not use 0->255.
If you do want to use 256 stops in a channel (32 bit) use the Color32 datatype instead.
Otherwise, convert your values to 0->1 and use Color.
Color is used by most APIs, and can support HDR values.
Color32 is implicitly convertable to Color, it's used in some contexts to reduce memory footprint (Mesh.colors32 for example).
The values shown in the color picker are based on your current settings and are not indicative of how they're stored in code.
Unity, huh, how?