how can I define css in root

[themoneyevo]

I want to change css in root

custom_css="""
    #.fc-event-past {
    #    opacity: 0.8;
    #}
    .fc-event-time {
        font-style: italic;
    }
    .fc-event-title {
        font-weight: 700;
        #color: #FFD700;
        color: #FFFFFF;
    }
    .fc-toolbar-title {
        font-size: 2rem;
    }
    .root {
        --fc-page-bg-color: #380304;
    }
"""

I tried root :root, they are not work. And， get error：

site-packages\streamlit\web\server\component_request_handler.py", line 56, in get
    with open(abspath, "rb") as file:
FileNotFoundError: [Errno 2]  site-packages\\streamlit_calendar\\frontend\\build\\bootstrap.min.css.map'