# Configuring The default options can be permanently set with a configuration file found in a standard folder for configuration, depending on your operating system: - Linux: `$XDG_CONFIG_HOME/oasis/default.json`. Usually this is `/home//.config/oasis/default.json` - Windows `%APPDATA%\oasis\default.json`. - Mac OS, `/Users//Library/Preferences/oasis/default.json` The configuration file can override any or all of the command-line _defaults_. Here is an example customizing the port number and the "open" settings: ```json { "open": false, "port": 19192 } ``` If you run `oasis --help` you'll see all of the parameters, which are also defined in the source code here: https://github.com/fraction/oasis/blob/master/src/cli.js ## Semantics Which value is given is decided like this: 1. If an argument is given on the command-line, use that value. 2. Otherwise, use the value from the configuration file if present. 3. If neither command-line nor configuration file are given, use the built-in default value. # Custom Styles The stylesheet values may be overridden by adding custom values to a file found in a standard folder for configuration, depending on your operating system: - Linux: `$XDG_CONFIG_HOME/oasis/custom-style.css`. Usually this is `/home//.config/oasis/custom-style.css` - Windows `%APPDATA%\oasis\custom-style.css`. - Mac OS, `/Users//Library/Preferences/oasis/custom-style.css` As an example the width used for the main body may be changed to a different fixed width or a dynamic width: ```css :root { --measure: 75%; } ```