The seven deadly sins are not the mortal sins, and the two are confused constantly, including in works that ought to know better. They are different classifications answering different questions, and the atlas holds both.
The seven are capital sins, and the word is doing precise work. Capital comes from caput, a head, and they are so called because they are heads or sources from which other sins spring. Pride, avarice, envy, wrath, lust, gluttony and sloth are named as roots of further sin rather than as a ranked schedule of offences, and nothing about membership of that list makes an act mortal. Whether a particular flash of anger or a particular indulgence is mortal is settled by the same three conditions as any other act: grave matter, full knowledge, deliberate consent. Most instances of most of the seven fail at least one of them.
The lineage of the list also lies outside this doctrine. It descends from the eight thoughts catalogued by Evagrius Ponticus in fourth century Egypt as assaults on a monk, carried west by John Cassian and reworked by Gregory the Great, where they were diagnostic categories in an ascetic programme rather than a penitential code. That history is treated in the atlas under the Orthodox reading of sin as illness.
There is a third layer, later again, and it should not be mistaken for either. The correspondences that pair each of the seven with a planet and a commanding demon come from the Renaissance and early modern esoteric tradition, not from the theological literature. The atlas carries them on the vice entries because they are a real feature of that tradition, and they are no part of the distinction described here.
The Reformation confessions rejected the mortal and venial scheme in the form the medieval penitential system had given it, holding that every sin is of itself worthy of God's wrath, while still allowing that not every sin extinguishes faith.