def default_graph_layout_options():
    """
    Default layout options for all graphs.
    :returns: a dict of default options.
    """
    return {
        "paper_bgcolor": "rgb(52, 58, 64)",
        "plot_bgcolor": "rgb(52, 58, 64)",
        "font": {
            "color": "rgba(255, 255, 255, 1)",
            # Bootstrap 4 font family.
            "family": '-apple-system, BlinkMacSystemFont, "Segoe UI", '
            'Roboto, "Helvetica Neue", Arial, sans-serif, '
            '"Apple Color Emoji", "Segoe UI Emoji", '
            '"Segoe UI Symbol"',
            "size": 14,
        },
        "margin": {"b": 80, "t": 80},
        "xaxis": {
            "titlefont": {"color": "rgba(255, 255, 255, 0.5)"},
            "gridcolor": "rgba(0, 0, 0, 0.25)",
            "zerolinecolor": "rgba(0, 0, 0, 0.5)",
        },
        "yaxis": {
            "titlefont": {"color": "rgba(255, 255, 255, 0.5)"},
            "gridcolor": "rgba(0, 0, 0, 0.25)",
            "zerolinecolor": "rgba(0, 0, 0, 0.5)",
        },
    }

    Default layout options for all graphs.
    :returns: a dict of default options.
    
reports/utils.py