local custom_highlights = function(C)
  return {
    HopNextKey               = { bg    = C.text, fg           = C.base, style = { "bold", "underline" } },
    HopNextKey1              = { bg    = C.text, fg           = C.base, style = { "bold" } },
    HopNextKey2              = { bg    = C.text, fg           = C.base, style = { "bold", "italic" } },
    DiagnosticUnderlineError = { style = { "undercurl" } },
    DiagnosticUnderlineWarn  = { style = { "undercurl" } },
    DiagnosticUnderlineInfo  = { style = { "undercurl" } },
    DiagnosticUnderlineHint  = { style = { "undercurl" } },
    DiagnosticUnderlineOk    = { style = { "undercurl" } },
    -- Function              = { fg    = C.blue, style        = { "bold" } },
    -- Keyword               = { fg    = C.black, style       = { "italic" } },
    Type                     = { fg    = C.text },
    --
    -- syntax
    Constant                 = { fg    = C.text },
    String                   = { fg    = C.text },
    Character                = { fg    = C.text },
    Number                   = { fg    = C.text },
    Float                    = { fg    = C.text },
    Boolean                  = { fg    = C.text },
    Identifier               = { fg    = C.text },
    Function                 = { fg    = C.text },
    Statement                = { fg    = C.text },
    Conditional              = { fg    = C.text },
    Repeat                   = { fg    = C.text },
    Label                    = { fg    = C.text },
    Operator                 = { fg    = C.text },
    Keyword                  = { fg    = C.text },
    Exception                = { fg    = C.text },
    PreProc                  = { fg    = C.pink },
    Include                  = { fg    = C.pink },
    Define                   = { fg    = C.pink },
    Macro                    = { fg    = C.pink },
    PreCondit                = { fg    = C.pink },
    StorageClass             = { fg    = C.text },
    Structure                = { fg    = C.text },
    Special                  = { fg    = C.text },
    Type                     = { fg    = C.text },
    Typedef                  = { fg    = C.text },
    SpecialChar              = { fg    = C.text },
    Tag                      = { fg    = C.text },
    Delimiter                = { fg    = C.text },
    Debug                    = { fg    = C.text },

    -- Underlined               = { style = { "underline" } },                          -- (preferred) text that stands out, HTML links
    -- Bold                     = { style = { "bold" } },
    -- Italic                   = { style = { "italic" } },
    -- ("Ignore", below, may be invisible...)
    -- Ignore                = { }, -- (preferred) left blank, hidden  |hl-Ignore|

    -- Error                    = { fg    = C.red },                                    -- (preferred) any erroneous construct
    -- Todo                     = { bg    = C.flamingo, fg       = C.base, style = { "bold" } }, -- (preferred) anything that needs extra attention; mostly the keywords TODO FIXME and XXX
    -- qfLineNr                 = { fg    = C.yellow },
    -- qfFileName               = { fg    = C.blue },
    -- htmlH1                   = { fg    = C.pink, style        = { "bold" } },
    -- htmlH2                   = { fg    = C.blue, style        = { "bold" } },
    -- -- mkdHeading            = { fg    = C.peach, style       = { "bold" } },
    -- -- mkdCode               = { bg    = C.terminal_black, fg = C.text },
    -- mkdCodeDelimiter         = { bg    = C.base, fg           = C.text },
    -- mkdCodeStart             = { fg    = C.flamingo, style    = { "bold" } },
    -- mkdCodeEnd               = { fg    = C.flamingo, style    = { "bold" } },
    -- -- mkdLink               = { fg    = C.blue, style        = { "underline" } },
    --
    -- -- debugging
    -- debugPC                  = { bg    = O.transparent_background and C.none or C.crust }, -- used for highlighting the current line in terminal-debug
    -- debugBreakpoint          = { bg    = C.base, fg           = C.overlay0 },              -- used for breakpoint colors in terminal-debug
    -- -- illuminate
    -- illuminatedWord          = { bg    = C.surface1 },
    -- illuminatedCurWord       = { bg    = C.surface1 },
    -- -- diff
    -- diffAdded                = { fg    = C.green },
    -- diffRemoved              = { fg    = C.red },
    -- diffChanged              = { fg    = C.blue },
    -- diffOldFile              = { fg    = C.yellow },
    -- diffNewFile              = { fg    = C.peach },
    -- diffFile                 = { fg    = C.blue },
    -- diffLine                 = { fg    = C.overlay0 },
    -- diffIndexLine            = { fg    = C.teal },
    -- DiffAdd                  = { bg    = U.darken(C.green, 0.18, C.base) }, -- diff mode: Added line |diff.txt|
    -- DiffChange               = { bg    = U.darken(C.blue, 0.07, C.base) }, -- diff mode: Changed line |diff.txt|
    -- DiffDelete               = { bg    = U.darken(C.red, 0.18, C.base) }, -- diff mode: Deleted line |diff.txt|
    -- DiffText                 = { bg    = U.darken(C.blue, 0.30, C.base) }, -- diff mode: Changed text within a changed line |diff.txt|
    -- -- NeoVim
    -- healthError              = { fg    = C.red },
    -- healthSuccess            = { fg    = C.teal },
    -- healthWarning            = { fg    = C.yellow },
    -- -- misc
    --
    -- -- glyphs
    -- GlyphPalette1            = { fg    = C.red },
    -- GlyphPalette2            = { fg    = C.teal },
    -- GlyphPalette3            = { fg    = C.yellow },
    -- GlyphPalette4            = { fg    = C.blue },
    -- GlyphPalette6            = { fg    = C.teal },
    -- GlyphPalette7            = { fg    = C.text },
    -- GlyphPalette9            = { fg    = C.red },
    --
    -- -- rainbow
    -- rainbow1                 = { fg    = C.red },
    -- rainbow2                 = { fg    = C.peach },
    -- rainbow3                 = { fg    = C.yellow },
    -- rainbow4                 = { fg    = C.green },
    -- rainbow5                 = { fg    = C.sapphire },
    -- rainbow6                 = { fg    = C.lavender },
    --
    -- -- csv
    -- csvCol0                  = { fg    = C.red },
    -- csvCol1                  = { fg    = C.peach },
    -- csvCol2                  = { fg    = C.yellow },
    -- csvCol3                  = { fg    = C.green },
    -- csvCol4                  = { fg    = C.sky },
    -- csvCol5                  = { fg    = C.blue },
    -- csvCol6                  = { fg    = C.lavender },
    -- csvCol7                  = { fg    = C.mauve },
    -- csvCol8                  = { fg    = C.pink },
  }
end

return custom_highlights