Steam skin maker: how to create custom Steam skins in the new client

A Steam skin maker is a tool that changes the colors, fonts and layout of the Steam desktop client. The classic option, Steam Customizer, built skins for the old Steam interface, but Valve dropped built-in skin support when it moved the client to a web-based UI in 2023. Today you make and apply custom Steam skins with community patchers such as Millennium or SFP, which style the new client with CSS.

This guide explains what changed, which Steam customization tools work with the current client, how to create your own skin, and what to check before you install a patcher.

What happened to Steam Customizer and classic Steam skins

Steam Customizer was a free web-based Steam skin creator paired with a small open source Windows loader. On the site you picked a font, primary and secondary colors, client colors for elements such as the inbox and search field, a custom PNG logo, and status colors for online, offline and in-game. You then downloaded the generated skin and applied it with the Steam Customizer program, either from its list or by double-clicking the skin file.

That workflow depended on the old VGUI skin system covered in our classic Steam skins overview. Valve rebuilt the client interface on the Chromium Embedded Framework, and the Valve Developer Community wiki now states that Steam skins lost official support and only work through community patching methods. Users in the Steam Client Beta group confirmed in August 2023 that skin support was removed with the UI update. Skins made with Steam Customizer for the old client therefore do not load in the current one.

Steam skin makers compared: current and classic client

Two open source projects restore custom Steam skins on the new client: Millennium and SFP. Both inject CSS into the web-based interface instead of using the old skin folder.

Millennium is the most complete option for most people: you install it once, browse themes on steambrew.app and switch between them. SFP is lighter and suits users who want to write or drop in their own CSS files. Skin authors have followed the same path: the maker of the popular Metro skin pointed users to SFP after the switch and later recommended Millennium with the MetroSteam theme, according to the Metro for Steam group.

How to create a custom Steam skin with Millennium

Creating a custom Steam skin with Millennium means picking a base theme and editing its CSS in the built-in editor. The general workflow looks like this:

1. Close Steam and install Millennium using the installation guide linked from steambrew.app.
2. Start Steam and open the Millennium settings to see installed themes.
3. Download a theme from the steambrew.app theme library as a starting point, or start from the default look.
4. Open the built-in CSS editor and change colors, fonts, spacing or backgrounds; changes show live in the client.
5. Keep a copy of your CSS outside the Steam folder so you can restore it after an update.

If you want to build a full theme to share, Millennium's developer documentation at docs.steambrew.app covers themes and plugins. A practical tip from the old Steam Customizer days still applies: change one element at a time and check the friends list and dialog windows too, because large fonts can break alignment in parts of the client you do not look at often.

How to apply your own CSS skin with SFP

SFP applies a Steam skin from plain CSS files, which makes it a simple Steam skin maker for people comfortable with web styling. Its README lists the moving parts:

• Steam must run with the "-cef-enable-debugging" launch argument; SFP adds it when it starts Steam, and its "Force Steam arguments" setting (on by default) restarts Steam with it if it is missing.
• Library and client styles go into files such as "libraryroot.custom.css", and store or community page styles into "webkit.css".
• A "skin.json" file can define per-page rules.
• Custom JavaScript is supported but disabled by default; leave it off unless you trust the script.

Download SFP only from its GitHub releases page and pick the self-contained build unless you already have .NET 7 installed.

Is it safe to skin the Steam client?

Skinning the Steam client with a patcher is a cosmetic change, but the tools are unofficial and you should treat them that way. Millennium states that Steam Homebrew is not affiliated with or endorsed by Valve, and the Valve wiki describes all current skin methods as community patching. Before you install one, run through this checklist:

• Download Millennium or SFP only from steambrew.app or the official GitHub repositories, never from re-uploads.
• Install themes from the official library or from authors you can verify.
• Expect a Steam client update to break a theme now and then, and keep your own CSS backed up.
• Avoid enabling JavaScript injection or plugins you have not reviewed.
• If Steam misbehaves, disable the theme or remove the patcher before you troubleshoot anything else.

Millennium also says it blocks Steam analytics and crash reporting by default, which privacy-minded users may like, but it means crash reports will not reach Valve if you need support. Valve's own customization options are limited to your Steam profile, for example items from the Points Shop, and they do not change the look of the client itself.

FAQ

Related: change your Steam privacy settings, configure or block Steam notifications, stop Steam from updating games automatically