diff --git a/CHANGELOG.md b/CHANGELOG.md
index f179147..1f62853 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,7 +1,18 @@
 # Changelog
+
 All notable changes to this project will be documented in this file. This
 project adheres to [Semantic Versioning].
 
+## [Unreleased]
+
+### Changed
+
+- The color of the highlight group 'Operator' has been modified. This group is
+  now associated to the green color.
+
+- The color of the highlight groups 'StorageClass', 'Structure' and 'Typedef'
+  have been modified. They are now colorized with the cyan colors.
+
 ## [0.3.0] - 2019-03-16
 
 ### Changed
@@ -108,6 +119,7 @@ project adheres to [Semantic Versioning].
 
   + Otherwise, a GUI version of Vim must be used.
 
+[Unreleased]: https://github.com/ludokng/vim-odyssey/compare/0.3.0...HEAD
 [0.3.0]: https://github.com/ludokng/vim-odyssey/compare/0.2.0...0.3.0
 [0.2.0]: https://github.com/ludokng/vim-odyssey/compare/0.1.0...0.2.0
 [Semantic Versioning]: https://semver.org/spec/v2.0.0.html
diff --git a/colors/odyssey.vim b/colors/odyssey.vim
index ab60f02..cfdc261 100644
--- a/colors/odyssey.vim
+++ b/colors/odyssey.vim
@@ -180,78 +180,85 @@ endfunction
 " }}}
 " User Interface {{{
 
-call s:HL(      'SpecialKey', 'background',    'warning', 'none')
-call s:HL(     'EndOfBuffer', 'background', 'linenumber', 'none')
-call s:HL(         'NonText', 'background', 'linenumber', 'none')
-call s:HL(       'Directory', 'background', 'foreground', 'none')
-call s:HL(        'ErrorMsg', 'background',      'error', 'bold')
-call s:HL(         'MoreMsg', 'background',    'warning', 'none')
-call s:HL(         'ModeMsg', 'background',    'warning', 'none')
-call s:HL(       'IncSearch', 'background', 'foreground', 'reverse')
-call s:HL(          'Search', 'background', 'linenumber', 'reverse')
-call s:HL(          'LineNr', 'background', 'linenumber', 'none')
-call s:HL(    'CursorLineNr', 'cursorline', 'foreground', 'none')
-call s:HL(        'Question', 'background',    'warning', 'none')
-call s:HL(      'StatusLine', 'cursorline', 'foreground', 'none')
-call s:HL(    'StatusLineNC', 'beyondback', 'linenumber', 'none')
-call s:HL(       'VertSplit', 'beyondback', 'beyondback', 'none')
-call s:HL(           'Title', 'background',  'procedure', 'none')
-call s:HL(          'Visual', 'background', 'foreground', 'reverse')
-call s:HL(       'VisualNOS', 'background', 'foreground', 'reverse')
-call s:HL(      'WarningMsg', 'background',    'warning', 'bold')
-call s:HL(        'WildMenu', 'cursorline',    'warning', 'none')
-call s:HL(          'Folded', 'foldedline', 'linenumber', 'none')
-call s:HL(      'FoldColumn', 'foldedline', 'linenumber', 'none')
-call s:HL(         'DiffAdd',  'procedure', 'background', 'none')
-call s:HL(      'DiffChange',    'warning', 'background', 'none')
-call s:HL(      'DiffDelete',      'error', 'background', 'none')
-call s:HL(        'DiffText',      'error', 'background', 'none')
-call s:HL(      'SignColumn', 'background',      'error', 'none')
-call s:HL(         'Conceal', 'background',    'keyword', 'none')
+call s:HL(      'SpecialKey', 'background',    'warning',      'none')
+call s:HL(     'EndOfBuffer', 'background', 'linenumber',      'none')
+call s:HL(         'NonText', 'background', 'linenumber',      'none')
+call s:HL(       'Directory', 'background', 'foreground',      'none')
+call s:HL(        'ErrorMsg', 'background',      'error',      'bold')
+call s:HL(         'MoreMsg', 'background',    'warning',      'none')
+call s:HL(         'ModeMsg', 'background',    'warning',      'none')
+call s:HL(       'IncSearch', 'background', 'foreground',   'reverse')
+call s:HL(          'Search', 'background', 'linenumber',   'reverse')
+call s:HL(          'LineNr', 'background', 'linenumber',      'none')
+call s:HL(    'CursorLineNr', 'cursorline', 'foreground',      'none')
+call s:HL(        'Question', 'background',    'warning',      'none')
+call s:HL(      'StatusLine', 'cursorline', 'foreground',      'none')
+call s:HL(    'StatusLineNC', 'beyondback', 'linenumber',      'none')
+call s:HL(       'VertSplit', 'beyondback', 'beyondback',      'none')
+call s:HL(           'Title', 'background',  'procedure',      'none')
+call s:HL(          'Visual', 'background', 'foreground',   'reverse')
+call s:HL(       'VisualNOS', 'background', 'foreground',   'reverse')
+call s:HL(      'WarningMsg', 'background',    'warning',      'bold')
+call s:HL(        'WildMenu', 'cursorline',    'warning',      'none')
+call s:HL(          'Folded', 'foldedline', 'linenumber',      'none')
+call s:HL(      'FoldColumn', 'foldedline', 'linenumber',      'none')
+call s:HL(         'DiffAdd',  'procedure', 'background',      'none')
+call s:HL(      'DiffChange',    'warning', 'background',      'none')
+call s:HL(      'DiffDelete',      'error', 'background',      'none')
+call s:HL(        'DiffText',      'error', 'background',      'none')
+call s:HL(      'SignColumn', 'background',      'error',      'none')
+call s:HL(         'Conceal', 'background',    'keyword',      'none')
 call s:HL(        'SpellBad', 'background',      'error', 'underline')
 call s:HL(        'SpellCap', 'background',    'warning', 'underline')
 call s:HL(       'SpellRare', 'background',   'constant', 'underline')
 call s:HL(      'SpellLocal', 'background',    'keyword', 'underline')
-call s:HL(           'Pmenu', 'foldedline', 'linenumber', 'none')
-call s:HL(        'PmenuSel', 'background', 'foreground', 'reverse')
-call s:HL(       'PmenuSbar', 'foldedline', 'foldedline', 'none')
-call s:HL(      'PmenuThumb', 'linenumber', 'linenumber', 'none')
-call s:HL(         'TabLine', 'background', 'linenumber', 'none')
-call s:HL(      'TabLineSel', 'background', 'foreground', 'none')
-call s:HL(     'TabLineFill', 'beyondback', 'linenumber', 'none')
-call s:HL(    'CursorColumn', 'cursorline', 'foreground', 'none')
-call s:HL(      'CursorLine', 'cursorline',       'none', 'none')
-call s:HL(     'ColorColumn', 'foldedline',       'none', 'none')
-call s:HL(  'StatusLineTerm', 'cursorline', 'foreground', 'none')
-call s:HL('StatusLineTermNC', 'beyondback', 'linenumber', 'none')
-call s:HL(          'Cursor', 'background', 'foreground', 'reverse')
-call s:HL(         'lCursor', 'background', 'foreground', 'reverse')
+call s:HL(           'Pmenu', 'foldedline', 'linenumber',      'none')
+call s:HL(        'PmenuSel', 'background', 'foreground',   'reverse')
+call s:HL(       'PmenuSbar', 'foldedline', 'foldedline',      'none')
+call s:HL(      'PmenuThumb', 'linenumber', 'linenumber',      'none')
+call s:HL(         'TabLine', 'background', 'linenumber',      'none')
+call s:HL(      'TabLineSel', 'background', 'foreground',      'none')
+call s:HL(     'TabLineFill', 'beyondback', 'linenumber',      'none')
+call s:HL(    'CursorColumn', 'cursorline', 'foreground',      'none')
+call s:HL(      'CursorLine', 'cursorline',       'none',      'none')
+call s:HL(     'ColorColumn', 'foldedline',       'none',      'none')
+call s:HL(  'StatusLineTerm', 'cursorline', 'foreground',      'none')
+call s:HL('StatusLineTermNC', 'beyondback', 'linenumber',      'none')
+call s:HL(          'Cursor', 'background', 'foreground',   'reverse')
+call s:HL(         'lCursor', 'background', 'foreground',   'reverse')
 call s:HL(      'MatchParen', 'background',    'warning', 'underline')
-call s:HL(     'ToolbarLine', 'linenumber', 'linenumber', 'none')
-call s:HL(   'ToolbarButton', 'background', 'linenumber', 'reverse')
+call s:HL(     'ToolbarLine', 'linenumber', 'linenumber',      'none')
+call s:HL(   'ToolbarButton', 'background', 'linenumber',   'reverse')
+call s:HL(          'Normal', 'background', 'foreground',      'none')
 
 " }}}
 " Default Syntax {{{
 
-call s:HL(         'Comment', 'background', 'linenumber', 'none')
-call s:HL(        'Constant', 'background',   'constant', 'none')
-call s:HL(         'Special', 'background',    'warning', 'none')
-call s:HL(      'Identifier', 'background',  'procedure', 'none')
-call s:HL(       'Statement', 'background',    'keyword', 'none')
-call s:HL(         'Preproc', 'background',    'warning', 'none')
-call s:HL(            'Type', 'background',       'type', 'none')
-call s:HL(      'Underlined', 'background', 'foreground', 'underline')
-call s:HL(          'Ignore', 'background', 'background', 'none')
-call s:HL(           'Error', 'background',      'error', 'bold')
-call s:HL(            'Todo', 'background',    'warning', 'bold')
-call s:HL(          'String', 'background',   'constant', 'none')
-call s:HL(          'Number', 'background',   'constant', 'none')
-call s:HL(        'Function', 'background',  'procedure', 'none')
-call s:HL(     'Conditional', 'background',    'keyword', 'none')
-call s:HL(             'Tag', 'background',    'warning', 'none')
-call s:HL(     'SpecialChar', 'background',    'warning', 'none')
-call s:HL(       'Delimiter', 'background',    'warning', 'none')
-call s:HL(          'Normal', 'background', 'foreground', 'none')
+call s:HL(     'Comment', 'background', 'linenumber',      'none')
+
+call s:HL(    'Constant', 'background',   'constant',      'none')
+
+call s:HL(  'Identifier', 'background',  'procedure',      'none')
+
+call s:HL(   'Statement', 'background',    'keyword',      'none')
+call s:HL(    'Operator', 'background',  'procedure',      'none')
+
+call s:HL(     'Preproc', 'background',    'warning',      'none')
+
+call s:HL(        'Type', 'background',       'type',      'none')
+call s:HL('StorageClass', 'background',    'keyword',      'none')
+call s:HL(   'Structure', 'background',    'keyword',      'none')
+call s:HL(     'Typedef', 'background',    'keyword',      'none')
+
+call s:HL(     'Special', 'background',    'warning',      'none')
+
+call s:HL(  'Underlined', 'background', 'foreground', 'underline')
+
+call s:HL(      'Ignore', 'background', 'background',      'none')
+
+call s:HL(       'Error', 'background',      'error',      'bold')
+
+call s:HL(        'Todo', 'background',    'warning',      'bold')
 
 " }}}
 " vim: foldmethod=marker