How to highlight Python class names in Vim (custom colorscheme)?

I’m working on a custom Vim colorscheme (Monokai-inspired with a Gruvbox background, 256-color accurate) and I’d like to highlight Python class names in a different color. I'm using Vim macOS version - arm64.

Here’s what I’ve tried so far in my colors/cloud.vim:

    " Python specific
hi pythonFunction     ctermfg=118 cterm=bold
hi pythonBuiltin      ctermfg=81  cterm=bold
hi pythonSelf         ctermfg=161 cterm=italic

" Function and class name highlighting
autocmd FileType python syntax match pythonFunctionName /\<\h\w*\ze\s*(/
autocmd FileType python hi pythonFunctionName ctermfg=118 cterm=bold

autocmd FileType python syntax match pythonClassName /\<class\s\+\zs\h\w*/
autocmd FileType python hi pythonClassName ctermfg=81 cterm=bold

The function highlighting (pythonFunctionName) works fine, but the class name highlighting does not show up at all. For example:

class MyExample:
    def do_something(self):
        pass

Here, MyExample doesn’t get highlighted differently, even though my regex looks like it should catch it.

I’ve tried clearing/redefining pythonStatement and related groups, but no luck.

How can I properly highlight class names in Python files in Vim when using a custom colorscheme?

Do I need to contains / contained the match somewhere, or is there a better way to hook into Python syntax groups?

My full file is as follow:

" Monokai (Python-focused) with Gruvbox background - 256 colors accurate
hi clear
set background=dark
if version > 580
    hi clear
    if exists("syntax_on")
        syntax reset
    endif
endif
let g:colors_name="claude"
" Base UI (cterm)
hi Normal          ctermfg=188 ctermbg=235
hi Comment         ctermfg=244 cterm=italic
hi CursorLine                  ctermbg=237
hi CursorColumn                ctermbg=237
hi LineNr          ctermfg=241 ctermbg=235
hi NonText         ctermfg=239 ctermbg=235
hi VertSplit       ctermfg=239 ctermbg=235
hi StatusLine      ctermfg=188 ctermbg=239 cterm=bold
hi StatusLineNC    ctermfg=244 ctermbg=237
hi Visual                      ctermbg=239
hi Search          ctermfg=235 ctermbg=186 cterm=bold
hi IncSearch       ctermfg=235 ctermbg=208 cterm=bold
hi MatchParen      ctermfg=235 ctermbg=161 cterm=bold
" Popup menu
hi Pmenu           ctermfg=188 ctermbg=237
hi PmenuSel        ctermfg=235 ctermbg=118 cterm=bold
hi PmenuSbar                   ctermbg=239
hi PmenuThumb      ctermfg=81
" General syntax
hi Identifier      ctermfg=252              " Variables - Yellow
hi Function        ctermfg=118              " Functions - Green
hi Statement       ctermfg=135 cterm=bold   " Keywords - Purple
hi Operator        ctermfg=161              " Operators - Red
hi Keyword         ctermfg=135 cterm=bold   " Keywords - Purple
hi Constant        ctermfg=135              " Constants - Purple
hi String          ctermfg=221              " Strings - Orange
hi Number          ctermfg=135              " Numbers - Purple
hi Boolean         ctermfg=135 cterm=bold   " Booleans - Purple
hi Type            ctermfg=81               " Types - Blue
hi Special         ctermfg=81  cterm=italic
hi Delimiter       ctermfg=161
hi Error           ctermfg=161 ctermbg=235 cterm=bold,underline
hi Todo            ctermfg=235 ctermbg=220 cterm=bold
" Python specific
hi pythonStatement    ctermfg=135 cterm=bold
hi pythonConditional  ctermfg=161 cterm=bold
hi pythonRepeat       ctermfg=161 cterm=bold
hi pythonOperator     ctermfg=161 cterm=bold
hi pythonInclude      ctermfg=161 cterm=bold
hi pythonFunction     ctermfg=118 cterm=bold
hi pythonComment      ctermfg=244 cterm=italic
hi pythonString       ctermfg=221
hi pythonNumber       ctermfg=135
hi pythonBuiltin      ctermfg=81  cterm=bold
hi pythonSelf         ctermfg=161 cterm=italic
" Define colors for our custom attribute highlighting
hi MyDot              ctermfg=161              " Dots - Red  
hi MyAttr             ctermfg=208              " Attributes after dots - Orange
" Set up the working syntax highlighting for Python files
augroup PythonAttributeHighlight
    autocmd!
    autocmd FileType python syntax match MyDot /\./
    autocmd FileType python syntax match MyAttr /[a-zA-Z_][a-zA-Z0-9_]*/ contained
    autocmd FileType python syntax region MyDotted start=/\./ end=/\>/ contains=MyDot,MyAttr
    
    " Function name highlighting
    autocmd FileType python syntax match pythonFunctionName /\<\h\w*\ze\s*(/
    autocmd FileType python hi pythonFunctionName ctermfg=118 cterm=bold
    
    autocmd FileType python syntax match pythonClassName /\<class\s\+\zs\h\w*/
    autocmd FileType python hi pythonClassName ctermfg=81 cterm=bold
    " Custom flow control highlighting

    autocmd FileType python syntax clear pythonStatement
    autocmd FileType python syntax keyword pythonStatement def class with as import from global nonlocal lambda yield async await
    autocmd FileType python syntax keyword pythonFlowControl return break continue raise pass if else elif
    autocmd FileType python syntax keyword pythonRepeat for while do
    autocmd Filetype python syntax keyword pythonBoolean True False None
    autocmd FileType python hi pythonFlowControl ctermfg=161 cterm=bold 
    autocmd FileType python hi pythonRepeat ctermfg=161 cterm=bold
    autocmd FileType python hi pythonBoolean ctermfg=135 cterm=bold
    
    

augroup END

Thanks!