Gentle grass mowing curve along sidewalk?

Hello. Does anyone with more experience than me have any ideas for how to landscape along our new home addition's sidewalk? The large slope visible still needs some more dirtwork added/shaped to where it won't be quite as steep, blended into the grass below not pictured. I'd like a more gentle curve along the sidewalk for mowing purposes. I should've just had the concrete poured that way, but now that this what I have, what's the best looking way to fill in between the sidewalk and the grass, in a more gentle curved landscaping?

Hello. Does anyone with more experience than me have any ideas for how to landscape along our new home addition's sidewalk? The large slope visible still needs some more dirtwork added/shaped to where it won't be quite as steep, blended into the grass below not pictured. I'd like a more gentle curve along the sidewalk for mowing purposes. I should've just had the concrete poured that way, but now that this what I have, what's the best looking way to fill in between the sidewalk and the grass, in a more gentle curved landscaping?