Custom Karabiner-Elements ccos complex modification rule

karabiner.json

// ... all the bits before
{
    "description": "ccos + s to open Slack.",
    "manipulators": [
        {
            "from": {
                "key_code": "s",
                "modifiers": {
                    "mandatory": [
                        "shift",
                        "control",
                        "command",
                        "option"
                    ]
                }
            },
            "to": [
                {
                    "shell_command": "open -a /Applications/Slack.app"
                }
            ],
            "type": "basic"
        }
    ]
}
// ... all the bits after