Need Help Creating a custom version of bubbles theme

[HuM4NoiD]

I am trying to create a custom version of bubbles theme where sections lualine_a and lualine_z will appear as two pills/capsules at both the ends of the status line.
Declaration/Installation Using lazy.nvim:

return {
    "nvim-lualine/lualine.nvim",
    opts = require("config.statusline"),
}

Configuration:

local config = {}

local function modetext(str)
    return " " .. string.sub(str, 1, 3)
end

config.options = {
    icons_enabled = true,
    theme = "auto",
    section_separators = { left = "", right = "" },
    component_separators = "",
    globalstatus = true,
}

config.sections = {
    lualine_a = {
        { "mode", fmt = modetext, left_padding = 2, seperator = { left = "" } }
    },
    lualine_b = {
        { "diagnostics" },
    },
    lualine_c = {
        "%=",
        { "filetype", icon_only = true },
        { "filename" },
        { "location" },
    },
    lualine_x = {
    },
    lualine_y = {
        "diff",
    },
    lualine_z = {
        { "branch", right_padding = 2, seperator = { right = "" } },
    },
}

config.inactive_sections = {
    lualine_a = {},
    lualine_b = {},
    lualine_c = {
        "%=",
        { "filename" }
    },
    lualine_x = {},
    lualine_y = {},
    lualine_z = {},
}

return config

This is what I have achieved so far:

How do I get the lualine_a section to have a rounded (or any other shape) seperator on its left and lualine_z to have a seperator on its right?