A basic theme for hvega.
Usage, from the hvega example:
{-# LANGUAGE OverloadedStrings #-}
import Graphics.Vega.VegaLite
vl1 = toVegaLite [theme defaultConfiguration [], description desc, background "white", dat [], mark Bar barOpts, enc []] where
desc = "A very exciting bar chart"
dat = dataFromRows [Parse [("start", FoDate "%Y-%m-%d")]]
. dataRow [("start", Str "2011-03-25"), ("count", Number 23)]
. dataRow [("start", Str "2011-04-02"), ("count", Number 45)]
. dataRow [("start", Str "2011-04-12"), ("count", Number 3)]
barOpts = [MOpacity 0.4, MColor "teal"]
enc = encoding
. position X [PName "start", PmType Temporal, PAxis [AxTitle "Inception date"]]
. position Y [PName "count", PmType Quantitative]