Add Dark and Light "Professional" Themes

[GeorgeBerdovskiy]

Background

While PureChart provides maximal flexibility when it comes to chart styling, we do want to provide an abundance of default themes to choose from.

Following Ruby on Rails conventions, we've chosen to store chart styles in a specific folder. In the gem source code, they may be found under lib/purechart/styles as YML files. In a project using the gem, they must be inside of app/purechart and may be JSON, TOML, or YML / YAML files. Here's the default light theme as an example -

---
title:
  font: Inter Tight
  weight: 700
  color: "#000000"
labels:
  font: Inter Tight
  weight: 700
  color: "#000000"
ticks:
  font: Inter Tight
  weight: 400
  color: "#000000"
axes:
  style: "2px solid #000000"
gridlines:
  style: "2px dashed #00000033"
...

Goal

Create a new theme called "professional" that uses a serif font like Times New Roman (although the choice is yours) and provides a palette of muted or pastel colors.

• Use this page as a source on YAML syntax, including list definition
  • You'll need this because the colors should be defined as a list of dictionaries representing colors with two fields - name and hex value
• Visit Google Fonts for an excellent selection of free fonts!

[viveknarayana]

I'll work on this

[GeorgeBerdovskiy]

Closed by #8