chromium/third_party/blink/web_tests/inspector-protocol/css/resources/set-rule-selector.css

* {
    box-sizing: border-box;
}

html, body, div, a {
    /* resetting some properties */
    padding: 0;
    margin: 0;
    border: 0;
    display: flex; /* flex FTW! */
}

p:first-letter { font-size: 200%; } div,
body {
    position: relative;
}