how to decrease the brightness of a theme in vscode code example

Example 1: change vs code title bar theme color

"workbench.colorCustomizations": {
        "titleBar.activeBackground": "#ffffff",
        "titleBar.activeForeground": "#000000",
    }
    
    
    /*add this code in setting -> workbench -> edit json -> add above code */

Example 2: how can i change the color of the selection through mouse in fthe vscode

Add the following lines into "Editor: Token Color Customizations" setting, inside settings.json file.

"workbench.colorCustomizations": {
    "editor.selectionBackground": "#135564",
    "editor.selectionHighlightBackground": "#135564"
},