chromium/third_party/blink/web_tests/fast/css-intrinsic-dimensions/resources/intrinsic-size-contribution.css

.container {
    border: 5px solid blue;
    background-color: gray;
    margin-top: 10px;
}

.item {
    font: 10px/1 Ahem;
    height: 30px;
    background-color: orange;
}

.border { border: 5px solid red; }

.padding { padding: 10px; }

.margin { margin: 20px; }