my-nvim-setup/lua/plugins/bufferline.lua

local global_theme = "themes/" .. vim.g.nvchad_theme
local colors = require(global_theme)

local present, bufferline = pcall(require, "bufferline")
if not present then
    return
end

bufferline.setup {
    options = {
        offsets = {{filetype = "NvimTree", text = "", padding = 1}},
        buffer_close_icon = "",
        modified_icon = "",
        close_icon = "",
        left_trunc_marker = "",
        right_trunc_marker = "",
        max_name_length = 14,
        max_prefix_length = 13,
        tab_size = 20,
        show_tab_indicators = true,
        enforce_regular_tabs = false,
        view = "multiwindow",
        show_buffer_close_icons = true,
        separator_style = "thin",
        mappings = true,
        always_show_bufferline = true
    },
    highlights = {
        fill = {
            guifg = colors.grey_fg,
            guibg = colors.black2
        },
        background = {
            guifg = colors.grey_fg,
            guibg = colors.black2
        },
        -- buffers
        buffer_visible = {
            guifg = colors.light_grey,
            guibg = colors.black2
        },
        buffer_selected = {
            guifg = colors.white,
            guibg = colors.black,
            gui = "bold"
        },
        -- tabs
        tab = {
            guifg = colors.light_grey,
            guibg = colors.one_bg3
        },
        tab_selected = {
            guifg = colors.black2,
            guibg = colors.nord_blue
        },
        tab_close = {
            guifg = colors.red,
            guibg = colors.black
        },
        indicator_selected = {
            guifg = colors.black,
            guibg = colors.black
        },
        -- separators
        separator = {
            guifg = colors.black2,
            guibg = colors.black2
        },
        separator_visible = {
            guifg = colors.black2,
            guibg = colors.black2
        },
        separator_selected = {
            guifg = colors.black2,
            guibg = colors.black2
        },
        -- modified
        modified = {
            guifg = colors.red,
            guibg = colors.black2
        },
        modified_visible = {
            guifg = colors.red,
            guibg = colors.black2
        },
        modified_selected = {
            guifg = colors.green,
            guibg = colors.black
        },
        -- close buttons

        close_button = {
            guifg = colors.light_grey,
            guibg = colors.black2
        },
        close_button_visible = {
            guifg = colors.light_grey,
            guibg = colors.black2
        },
        close_button_selected = {
            guifg = colors.red,
            guibg = colors.black
        }
    }
}