Hey there! 
The User Interface looks nice, but I do have some feedback on this admin panel User Interface design.
Firstly, I suggest adding more detail to the UI. Perhaps rounded corners, more frames for the “X” and the other admin commands on the base frame. Adding more color to the UI maybe, like adding gradients to the UI and such. These are a few things you can do to add more detail to the User Interface.
Secondly, the positioning is off. Everything is just packed up all together. I see that the text labels and other UI elements on the User Interface are a bit squashed together. I would suggest to add a layout or just position the elements manually yourself (which every way works for you).
I’d mainly suggest adding more detail to the UI, positioning the elements a bit more properly so the elements don’t look squashed, and lastly, working on the sizing of the UI can make it look better. The sizes of the text labels are very different. I’d recommend resizing the text labels better so the UI is more tidy.
The contrast and such look fine, except for the “Reason Here” text and the “X” (close button). I’d recommend adding a non-transparent button base for the “X” as well as for the “Reason Here” recolored to be white.
Overall, the User Interface looks nice, but with working on the positioning, sizing, and detail of the User Interface, you can make the UI look better.
Good work on this User Interface you’ve designed! 
Hope this helped. 
-GameDevSky