tests/testgtk.css

/* testgtk2.css sets all the buttons in the main window to blue by default */
@import url("testgtk2.css");

* {
    font-family: Sans;
    font-size: 12px;
}

label:selected {
    background-color: gray;
}

label:hover {
    background-color: mix(#a0a0a0, rgb(75%, 78%, 0%), 0.9);
}

/* override testgtk2, introduce the green color in the button list */
#main_window scrolledwindow button:hover {
    background-color: rgb(0%, 75%, 0%);
}