How to edit default dark theme for Visual Studio Code?

In VS code 'User Settings', you can edit visible colours using the following tags (this is a sample and there are much more tags):

"workbench.colorCustomizations": {
    "list.inactiveSelectionBackground": "#C5DEF0",
    "sideBar.background": "#F8F6F6",
    "sideBar.foreground": "#000000",
    "editor.background": "#FFFFFF",
    "editor.foreground": "#000000",
    "sideBarSectionHeader.background": "#CAC9C9",
    "sideBarSectionHeader.foreground": "#000000",
    "activityBar.border": "#FFFFFF",
    "statusBar.background": "#102F97",
    "scrollbarSlider.activeBackground": "#77D4CB",
    "scrollbarSlider.hoverBackground": "#8CE6DA",
    "badge.background": "#81CA91"
}

If you want to edit some C++ color tokens, use the following tag:

"editor.tokenColorCustomizations": {
    "numbers": "#2247EB",
    "comments": "#6D929C",
    "functions": "#0D7C28"
}

The file you are looking for is at,

Microsoft VS Code\resources\app\extensions\theme-defaults\themes

on Windows and search for filename dark_vs.json to locate it on any other system.

---

Update:

With new versions of VSCode you don't need to hunt for the settings file to customize the theme. Now you can customize your color theme with the workbench.colorCustomizations and editor.tokenColorCustomizations user settings. Documentation on the matter can be found here.

As far as the themes, VS Code is every bit as editable as Sublime. You can edit any of the default themes that come with VS code. You just have to know where to find the theme files.

Side note: I love the Monokai theme. However, all I wanted to change about it was the background. I don't like the dark grayish background. Instead, I think the contrast is WAY better with a solid black background. The code pops out much more.

Anyways, I hunted for the theme file and found it (in windows) at:

c:\Program Files (x86)\Microsoft VS Code\resources\app\extensions\theme-monokai\themes\

In that folder I found the Monokai.tmTheme file and modified the first background key as follows:

<key>background</key>
<string>#000000</string>

There are a few 'background' key in the theme file, make sure you edit the correct one. The one I edited was at the very top. Line 12 I think.

The simplest way is to edit the user settings and customise workbench.colorCustomizations

If you want to make your theme

There is also the option modify the current theme which will copy the current theme settings and let you save it as a *.color-theme.json JSON5 file