def toggle_settings(toolbar=False, nbname=False, hideprompt=False,
    kernellogo=False):
    """Toggle main notebook toolbar (e.g., buttons), filename,
    and kernel logo."""
    toggle = ''
    if toolbar:
        toggle += 'div#maintoolbar {margin-left: 8px !important;}\n'
        toggle += '.toolbar.container {width: 100% !important;}\n'
    else:
        toggle += 'div#maintoolbar {display: none !important;}\n'
    if nbname:
        toggle += """span.save_widget span.filename {margin-left: 8px; height: initial;font-size: 100%; color: @nb-name-fg; background-color:@cc-input-bg;}
"""
        toggle += """span.save_widget span.filename:hover {color:@nb-name-hover; background-color: @cc-input-bg;}
"""
        toggle += (
            '#menubar {padding-top: 4px; background-color:@notebook-bg;}\n')
    else:
        toggle += '#header-container {display: none !important;}\n'
    if hideprompt:
        toggle += 'div.prompt.input_prompt {display: none !important;}\n'
        toggle += 'div.prompt.output_prompt {width: 5ex !important;}\n'
        toggle += """div.out_prompt_overlay.prompt:hover {width: 5ex !important; min-width: 5ex !important;}
"""
        toggle += """.CodeMirror-gutters, .cm-s-ipython .CodeMirror-gutters{ position: absolute; left: 0; top: 0; z-index: 3; width: 2em; display: inline-block !important; }
"""
        toggle += """div.cell.code_cell .input { border-left: 5px solid @cm-gutters !important; border-bottom-left-radius: 5px; border-top-left-radius: 5px; }
"""
    if kernellogo:
        toggle += '@kernel-logo-display: block;'
    else:
        toggle += '@kernel-logo-display: none;'
    return toggle
