Unless you have a userscript that modifies the site's design (or even if so), you should have noticed that we have our site design!

_{^{(It's November now)}}

So, to celebrate, let's make a program that retroactively applies this design (oversimplified, of course)!

So, the most important changes are:

• our new name is now Code Golf and Coding Challenges


• our site is no longer the default blue color and is instead a nice dark green

So, given a string, change:

• 
  PPCG to CGCC
  


• 
  Programming Puzzles non-whitespace Code Golf to Code Golf same-thing Coding Challenges (for example, Programming Puzzles + Code Golf, and Code Golf, and & Code Golf would all be changed to Code Golf + Coding Challenges, and Coding Challenges, and & Code Golf.


• 
  #abc to #acb (swap blue to green and vice versa - just ignore the fact that green shouldn't logically become blue but I don't want to complicate the color shifting)


• 
  #abcdef to #abefcd (same as above)

Note that for the color swaps, you should accept any hexadecimal digit from 0-9 to a-f. You can choose what case of hex digit to require, but it must be consistent and the same from input to output.

Your substitutions can be case-sensitive, and if not, please specify how the output works.

The substitutions should only happen when the string is surrounded by word boundaries (including the start of the #). In other words, each of the specified substitutions should only occur if the match is at the edge of the string or is bordered by non-alphanumeric characters (on both sides).

Standard loopholes apply. This is a code-golf challenge, so the shortest code wins!

Examples

PPCG -> CGCC
Programming Puzzles or Code Golf -> Code Golf or Coding Challenges
PPCG stands for Programming Puzzles and Code Golf and its site color is #abf -> CGCC stands for Code Golf and Coding Challenges and its site color is #afb
The color #00f is much more intense than #5568ed -> The color #0f0 is much more intense than #55ed68

Important Update

(Thanks @tsh)

The Programming Puzzles ... Code Golf substitution rule can include the other rules inside of it (Programming Puzzles PPCG Code Golf is valid). In this case, you may choose whether or not the rules are applied, but it must be deterministic. I'm not requiring that you be consistent between PPCG and #... because answers seem to implement the rules in my list ordering which results in inconsistencies. This is just a clarification; I believe all current answers remain valid.

Ruby -p, 165 164 159 bytes

It ended up being very similar to the sed answer, but it abuses Ruby's string interpolation to duplicate the hex group matching ([da-f]1,2) within the third regex three times instead of needing to repeat the whole thing again.

• -1 byte from @randomdude999.


• -5 bytes from leveraging @Xcali's Perl solution

gsub /bPPCGb/,"CGCC"
gsub /bProgramming Puzzles( S+ )(Code Golf)b/,'21Coding Challenges'
[1,2].map

Try it online!

GNU sed -E, 198 chars

s/bPPCGb/CGCC/g
s/bProgramming Puzzles( S* Cod)e Golfb/Code Golf1ing Challenges/g
s/((^|W)#[0-9a-f])([0-9a-f])([0-9a-f])b/143/g
s/((^|W)#[0-9a-f]2)([0-9a-f]2)([0-9a-f]2)b/143/g

Runnable using e.g. sed -E 'the above'; newlines can either be included literally, or replaced with ; if you so wish. Both work.

@HyperNeutrino come on that word boundary rule is stupid. Look what I had to do in the # case.

Yes, I didn't even try. :P

+9 by @Value Ink

Retina 0.8.2, 153 bytes

bPPCGb
CGCC
bProgramming Puzzles( S+ )(Code Golf)b
$2$1Coding Challenges
B(#[da-f]([da-f])?)([da-f](?(2)[da-f]))([da-f](?(2)[da-f]))b
$1$4$3

Try it online! Link includes test cases. All substitutions are case sensitive. Assumes normal regex word characters are acceptable so that B# matches only #s that don't follow a word character.

Python 2, 240 bytes

import re
lambda x,s=re.sub,b='(?<!w)',e='(?!w)',h='([da-f]',t=r'#132':s(b+'#%s2)'%h+h+'2)%s2)'%h+e,t,s(b+'#%s)'%h+h+')%s)'%h+e,t,s(b+'Programming Puzzles( S+ Cod)e Golf'+e,r'Code Golf1ing Challenges',s(b+'PPCG'+e,'CGCC',x))))

Try it online!