Dark/light mode

[UgurEkim]

Hi,

Implemented a dark/light toggle switch for changing theme's. Dark is more easier on the eyes on a big screen :). Besides that i've converted default css files to sass and also added the gulp-sass plugin in order to build the css files. This was needed for the dark/light mode.

Light Mode

Dark Mode

[carpikes]

Hi, thank you for the PR, I will have a look at it asap!

[UgurEkim]

Don't merge it yet, i still have a few optimizations and features. Right now there is nothing used regarding the sass (scss) files. The idea is that if you want to create your own theme you just create a new scss file with your theme colors and wrap them in this code block:

@include color-mode([insert_your_color_name]) {
// css color variables and others..
}

and with minimal changes to the code. Besides that i want to create scss for the controller part so people can customize them selfs with their own color choices. What we/i can introduce is creating a css class for every controller type. For example: you connect volcanic red controller so the controller svg shown is also volcanic red.

[UgurEkim]

You can review it fully now. I wanted to try and change colors of the controller. It did work but only for the buttons (all the infills) but not the body. For this i have to implement new svg's but thats tomuch work for now.

This PR contains code for switching between light and dark mode only.