I made a cleaner looking UI using the available JSON setting key value pairs to hopefully make your day a tad bit easier in editing colors.
"GUI": {
"Enabled": true,
"Main Box - Min Anchor (in Rust Window)": "0 1",
"Main Box - Max Anchor (in Rust Window)": "0 1",
"Main Box - Min Offset (in Rust Window)": "30 -330",
"Main Box - Max Offset (in Rust Window)": "470 -40",
"Main Box - Background Color": "0 0 0 0",
"Remove Title - Box - Min Anchor (in Main Box)": "0 0.84",
"Remove Title - Box - Max Anchor (in Main Box)": "0.996 1",
"Remove Title - Box - Background Color": "0.39 0.43 0.45 0.75",
"Remove Title - Text - Min Anchor (in Main Box)": "0.05 0.84",
"Remove Title - Text - Max Anchor (in Main Box)": "0.6 1",
"Remove Title - Text - Text Color": "0.87 0.90 0.91 1",
"Remove Title - Text - Text Size": 18,
"Timeleft - Box - Min Anchor (in Main Box)": "0.6 0.84",
"Timeleft - Box - Max Anchor (in Main Box)": "1 1",
"Timeleft - Box - Background Color": "0 0 0 0",
"Timeleft - Text - Min Anchor (in Timeleft Box)": "0 0",
"Timeleft - Text - Max Anchor (in Timeleft Box)": "0.9 1",
"Timeleft - Text - Text Color": "0.87 0.90 0.91 1",
"Timeleft - Text - Text Size": 15,
"Entity - Box - Min Anchor (in Main Box)": "0 0.68",
"Entity - Box - Max Anchor (in Main Box)": "1 0.84",
"Entity - Box - Background Color": "0.39 0.43 0.45 0.75",
"Entity - Text - Min Anchor (in Entity Box)": "0.05 0",
"Entity - Text - Max Anchor (in Entity Box)": "1 1",
"Entity - Text - Text Color": "0.87 0.90 0.91 1",
"Entity - Text - Text Size": 16,
"Entity - Image - Enabled": true,
"Entity - Image - Min Anchor (in Entity Box)": "0.795 0.01",
"Entity - Image - Max Anchor (in Entity Box)": "0.9 0.99",
"Authorization Check Enabled": true,
"Authorization Check - Box - Min Anchor (in Main Box)": "0 0.6",
"Authorization Check - Box - Max Anchor (in Main Box)": "1 0.68",
"Authorization Check - Box - Allowed Background Color": "0.18 0.80 0.44 0.75",
"Authorization Check - Box - Refused Background Color": "0.91 0.30 0.24 0.75",
"Authorization Check - Text - Min Anchor (in Authorization Check Box)": "0.05 0",
"Authorization Check - Text - Max Anchor (in Authorization Check Box)": "1 1",
"Authorization Check - Text - Text Color": "0.87 0.90 0.91 1",
"Authorization Check Box - Text - Text Size": 14,
"Price & Refund - Image Enabled": true,
"Price & Refund - Image Scale": 0.18,
"Price & Refund - Distance of image from right border": 0.05,
"Price Enabled": true,
"Price - Box - Min Anchor (in Main Box)": "0 0.3",
"Price - Box - Max Anchor (in Main Box)": "1 0.6",
"Price - Box - Background Color": "0.39 0.43 0.45 0.75",
"Price - Text - Min Anchor (in Price Box)": "0.05 0",
"Price - Text - Max Anchor (in Price Box)": "0.25 1",
"Price - Text - Text Color": "0.87 0.90 0.91 1",
"Price - Text - Text Size": 18,
"Price - Text2 - Min Anchor (in Price Box)": "0.3 0",
"Price - Text2 - Max Anchor (in Price Box)": "1 1",
"Price - Text2 - Text Color": "0.87 0.90 0.91 1",
"Price - Text2 - Text Size": 16,
"Refund Enabled": true,
"Refund - Box - Min Anchor (in Main Box)": "0 0",
"Refund - Box - Max Anchor (in Main Box)": "1 0.3",
"Refund - Box - Background Color": "0.39 0.43 0.45 0.75",
"Refund - Text - Min Anchor (in Refund Box)": "0.05 0",
"Refund - Text - Max Anchor (in Refund Box)": "0.25 1",
"Refund - Text - Text Color": "0.87 0.90 0.91 1",
"Refund - Text - Text Size": 18,
"Refund - Text2 - Min Anchor (in Refund Box)": "0.3 0",
"Refund - Text2 - Max Anchor (in Refund Box)": "1 1",
"Refund - Text2 - Text Color": "0.87 0.90 0.91 1",
"Refund - Text2 - Text Size": 16
},