Cells adjacent to green marks must total less than 10, blue must total 10, red must total more than 10. Also NC so horizontally/vertically adjacent cells cannot be {12}, {23}, … {78}, {89}, therefore at least one of the cells adjacent to each green mark must contain one of 1,2,3 as they cannot be {45}; similarly at least one of the cells adjacent to each red mark must contain one of 7,8,9 as they cannot be {56}.
[Note to myself for solving further MeanDokus. I note from wellbeback’s walkthrough that a cell with two red marks cannot contain 2. Similarly a cells with three red marks cannot contain 3, a cell with two green marks cannot contain 8 and a cell with three green marks cannot contain 7.]
Prelims.
Delete 9 from cells either side of green marks.
Delete 5 from cells either side of blue marks.
Delete 1 from cells either side of red marks.
Clean-ups and NCs only as stated.
1. No 9 in R45C4 -> no 1 in R45C4 (blue)
1a. R6C4 = 1 (hidden single in N5), placed for D/, R6C5 = 9 (blue), no 2 in R57C4 + R6C3, no 8 in R57C5 + R6C6 (NC)
1b. No 1 in R4C45 + R5C5 -> no 8 in R4C45 + R5C46 (green)
1c. R4C6 = 8 (hidden single in N5), placed for D/ -> no 2 in R4C5 + R5C6 (red), no 7 in R4C5 + R5C6, no 7,9 in R3C6 + R4C7 (NC)
1d. No 8 in R5C46 -> no 2 in R4C4 + R6C6 (blue)
1e. R5C5 = 2 (hidden single in N5), placed for both diagonals, no 3 in R4C5 + R5C46 (NC)
1f. R5C6 = {46} -> R56C6 = {46} (blue), locked for C6 and N5, no 5 in R6C7 (NC)
1g. R4C5 = 5, R5C4 = 7, R4C4 = 3, placed for D\
2. R23C6 = [73] (blue, only remaining permutation), no 6,8 in R2C5 (NC)
2a. R2C5 = 4 -> R1C5 = 6 (blue), R3C5 = 8, no 5 in R2C4 (NC)
2b. R2C4 = 2 -> R13C4 = [95], R1C6 = 1
2c. No 8 in R1C3, no 2 in R1C7, no 1,3 in R2C3, no 6,8 in R2C7, no 4,6 in R3C3, no 4 in R3C7, no 2,4 in R4C3, no 6,8 in R5C3 (NC)
2d. R78C4 must contain 8 (red) -> no 8 in R9C4
2e. R78C6 must contain 9 (red) -> no 9 in R9C6
2f. R9C4 = {46} -> no 5 in R9C3 (NC)
3. R3C23 = {19} (blue, only remaining permutation), locked for R3 and N1
3a. R2C23 = {58/68} (cannot be {56}, NC), 8 locked for R2 and N1
4. R56C3 = [37/46] (blue)
4a. Naked pair {67} in R46C3, locked for C3 and N4
4b. R6C3 = {67} -> R6C2 = {23} (green), no 3 in R5C2, no 2,3 in R6C1 + R7C2 (NC)
4c. R5C3 = {34} -> no 8 in R5C2 (green)
4d. 8 in N4 only in R56C1, locked for C1, no 9 in R5C1 (NC)
4e. 9 in N4 only in R4C12, locked for R4
4f. R4C3 = {67} -> no 2 in R4C2 (NC)
5. R3C7 = {67} -> no 6,7 in R3C8, no 6 in R4C7 (NC)
5a. R3C8 = {24} -> no 3 in R2C8 (NC)
5b. No 1 in R6C7 -> no 8 in R5C7 (green)
5c. R45C7 = [46] (blue, only remaining permutation), R3C7 = 7, placed for D/, R5C6 = 4, R6C6 = 6, placed for D\, R5C3 = 3, R46C3 = [67], R4C2 = 9, R3C2 = 1, R3C3 = 9, placed for D\, R5C2 = 5, R2C2 = 8, placed for D\, R2C3 = 5, R7C3 = 4, placed for D/, R1C3 = 2, R6C2 = 2, R4C1 = 1, R56C1 = [84], R1C1 = 7, placed for D\
6. R7C2 = {67} -> no 6,7 in R7C1, no 6 in R8C2 (NC)
6a. R8C2 = 3, placed for D/, R1C9 = 5, placed for D/, R3C1 = 6, R9C1 = 9, placed for D/
6b. R6C1 = 4 -> no 5 in R7C1 (NC)
6c. R78C1 = [25], R7C6 = 9 -> R7C5 = 1 (blue)
7. R6C78 = [35] (green, only remaining combination), R1C7 = 8, no 9 in R2C7 (NC)
The rest is naked singles, without using NC, diagonals or coloured marks.