style.css

/*
Theme Name: CSS-Tricks Theme Mod Demo
Theme URI: https://github.com/scofennell/csst-tmd
Author: Scott Fennell
Author URI: https://scottfennell.org/
Description: A placeholder theme to demonstrate the Theme Mod API.
Version: 1.0
License: GNU General Public License v2 or later
License URI: http://www.gnu.org/licenses/gpl-2.0.html
Tags: White, one-column, responsive-layout, custom-colors, editor-style, translation-ready
Text Domain: csst-tca

This theme, like WordPress, is licensed under the GPL.
Use it to make something cool, have fun, and share what you've learned with others.
*/

/**
 * Table of Contents
 *
 * 1.0. Frame
 * 2.0. Site Icon
 */

/**
 * 1.0. Frame
 */
	body {
		margin: 0 auto;
		color: #000;
		background: #fff;
	}

	.csst_tmd-page {
		background: rgba( 0, 0, 0, .15 );
		padding: 1em 2em;
		text-align: center;
		border: .25em solid #000;
	}

/**
 * 2.0 Site Icon
 */
	img {
		max-width: 100%;
		height: auto;
	}