(* ::Package:: *)
values = "
/* Keyword values */
flex: auto;
flex: initial;
flex: none;
/* One value, unitless number: flex-grow
flex-basis is then equal to 0. */
flex: 2;
/* One value, width/height: flex-basis */
flex: 10em;
flex: 30%;
flex: min-content;
/* Two values: flex-grow | flex-basis */
flex: 1 30px;
/* Two values: flex-grow | flex-shrink */
flex: 2 2;
/* Three values: flex-grow | flex-shrink | flex-basis */
flex: 2 2 10%;
/* Global values */
flex: inherit;
flex: initial;
flex: revert;
flex: unset;
";
all = Sort@StringCases[
values,
RegularExpression[":\\s*([a-zA-Z0-9-]+);"] :> "$1"
];
"[\"" <> StringRiffle[all, "\",\""] <> "\"].contains(&mode)"