div {
font-family: Arial, "Helvetica Neue", Helvetica, sans-serif;
}
div {
font-family: font-stack("Arial");
}
div {
background: #f00;
background: rgba(255,0,0,0.5);
}
div {
background: color-fallback(rgba(255,0,0,0.5));
}
button {
appearance: none;
}