Light and Darkness Rules

These are alternate and I think superior rules governing illumination. The goal is to have darkness be dangerous without being completely deadly to characters without darkvision, and still have Darkness spells be useful to dark dwellers.
I operate with three levels of illumination: Light (no concealment), Dim Light (concealment 20% mischance), and Darkness (total concealment 50% mischance).
I do not give "Bright Light" its own illumination category, because it is has the same concealment properties as Light, and that is what illumination is about. Whether the light is hurtful to a creature's eyes is a separate issue.
We all have a pretty clear idea of what happens when we light a torch in the dark, and the standard rules work fine for mundane light. A torch creates 20 feet radius of Light and an additional 20 feet of Dim Light. The problem occurs when we introduce magical light and darkness.
Here are the re-imagined Darkness Spells. With these spells darkness is not considered an opposite of light, but an absence of light, so the Darkness spells are an abjuration of light and not a radiation of darkness. No mundane source of light can penetrate an area of magical darkness. That means that the Darkness spell results in darkness (total concealment 50% mischance), if there are no magical sources of light present, and no matter what the mundane lighting conditions were before. Mundane light cannot penetrate magical darkness. This makes the Darkness Spell actually useful to a dark dweller, as a second level spell should be.
While mundane light cannot penetrate magical darkness, magical light can depending on its potency. The image above shows how the Light Cantrip interacts with the Darkness Spell creating an area of dim light within the are of darkness. Just like torches do not stack, multiple Light Spells cannot create more than dim light within the area of the Darkness Spell. The same is true for other spells that create light such as Dancing Lights and Continual Flame. Daylight* however is different, it is more potent than the other Light Spells, so it creates actual light within the area of the Darkness Spell.
Deeper Darkness is more potent than Darkness, so the Light Spells that create dim light under the Darkness Spell cannot illuminate an area of Deeper Darkness, but a Daylight* Spell can create dim light within Deeper Darkness, just like Light Spells can within Darkness.
I think these rules are more balanced in power between Light and Darkness, and easy to operate, because they keep magical and mundane light separate. Yet the magical Light and Darkness operate in a manner similar to the mundane.
One issue that has come up is seeing through an area of magical darkness to an area of light or dim light. I would suggest that you cannot see through an area of magical darkness without magical light.
*Daylight; I have moved Daylight to be a second level spell in stead of a third level spell, because I think it is too weak for a third level spell, and a second level Light Spell was called for.
*Low light vision; I decided to allow creatures with low light vision 5 feet without concealment under conditions of dim light (20% concealment), in addition to their normal double visibility range.