For example, you want to set 40% alpha transparence to #000000 (black color), you need to add 66 like this #66000000.
Code is clean if it can be understood easily – by everyone on the team. Clean code can be read and enhanced by a developer other than its original author. With understandability comes readability, changeability, extensibility and maintainability.
- Follow standard conventions.
 - Keep it simple stupid. Simpler is always better. Reduce complexity as much as possible.
 - Boy scout rule. Leave the campground cleaner than you found it.
 - Always find root cause. Always look for the root cause of a problem.