div {
    /* Unknown property, always generic */
    unknown-property: u;
    unknown-property: a value;
    unknown-property: one-value;
    unknown-property: multiple values;
    unknown-property: delimited, values;
    unknown-property: delimited / slash / values;
    unknown-property: mixed, delimiters / can be, used;

    /* Custom property, always generic */
    --custom-property: u;
    --custom-property: a value;
    --custom-property: one-value;
    --custom-property: multiple values;
    --custom-property: delimited, values;
    --custom-property: delimited / slash / values;
    --custom-property: mixed, delimiters / can be, used;


    /* Known property, incorrect values become generic */
    all: 10s;
    all: one-value;
    all: multiple values;
    all: delimited, values;
    all: delimited / slash / values;
    all: mixed, delimiters / can be, used;
}