nx_css_color_decode.nx

nx_css_color_decode.nx -- decode a CSS HEXCOLOR byte range into concrete (r, g, b, a) integers in [0, 255]. Phase 2.5 primitive bridging the value-as-bytes representation (from nx_css_tokenize / nx_css_parse / nx_css_apply) to the integer color consumed by the eventual nx_layout + nx_paint pipeline. Per CSS spec section 4.4 (CSS Color Module Level 4), valid hex color shapes are: #RGB 3-char form: each digit doubled (#abc -> #aabbcc) #RGBA 4-char form: same as above, last digit -> alpha #RRGGBB 6-char form: full RGB #RRGGBBAA 8-char form: full RGB + alpha All hex digits case-insensitive (0-9, a-f, A-F). What it does NOT handle (Phase 2b improvements): - named colors (red, blue, ...) -- handled by separate nx_css_color_named primitive (queued) - rgb() / rgba() / hsl() / hsla() functional notation - color-mix() / color() CSS-4 functions - currentColor / system colors / transparent keyword genealogy_id: w3c_css_color_module_level_4 + substrate_browser_phase_2_color_decode lineage_id: nishi_browser_css_color_decode_v1 nx_safety_envelope: intended_use: "CSS hex color decode -- layout/paint input" sil_target: SIL1 evidence: [W3C_CSS_Color_module_canonical_basis, sealed_4_supported_lengths, pure_function_no_allocation] verdict: NOT_YET_EVALUATED