I have no doubt that the days mentioned in the first chapter of Genesis are “literal days”. They each involve morning and evening, and so we can be even more specific: they are days according to traditional Jewish reckoning, beginning at sundown. Personally, I think that these literal days are part of a larger, extended metaphor of a divine “work-week”, but that isn’t the issue I want to focus on here.
There is at least one other place in the Bible where it is just as clear that literal days must be in view. In Matthew 12:38-40, Jesus is recorded as saying that the Son of Man will be in the belly of the earth for three days and three nights. Not ‘days’ in a broad, partial sense, but days and nights, in the literal sense.
From a scholarly perspective, this detail is a reinterpretation of the “sign of Jonah” by the author of Matthew’s Gospel. Originally, the “sign of Jonah” meant “no sign” since Jonah had given no sign (compare Mark and Luke on this point). And we already know from his genealogy that Matthew was interested in the symbolic value of numbers rather than numeric precision.
For those who claim to be Biblical literalists, scholarly considerations of that sort shouldn’t matter. Instead, self-proclaimed “Biblical literalists” should be arguing for the celebration either of Good Thursday or of Easter Monday.
But I have a better suggestion. If you are someone that wants a perfect Scripture that speak inerrantly and with precision, please go elsewhere. Stop trying to force Christianity and the Bible into this mold. It just doesn’t fit, and in trying to force it to, you do harm to the reputation of the Bible and its appreciation by those who actually read and study it, in detail, and are genuinely interested in understanding it on its own terms.