Hide tabs in Firefox 57

README.md

Hide tabs in Firefox 57

Place userChrome.css in ~/.mozilla/firefox/*.default/chrome/. Create the chrome folder if it does not exist.

• Hide the tab bar at the top of the window.
• Shrink sidebar-header.
• Make sidebar-header dark.

userChrome.css

#TabsToolbar {
    visibility: collapse;
}

#sidebar-header {
    font-size: 1em !important;
    padding: 0px !important;
}
#sidebar-box {
    background-color: var(--chrome-background-color) !important;
    color: var(--tab-text-color) !important;
}

#sidebar-header {
    border-bottom-color: var(--chrome-nav-bar-controls-border-color) !important;
}

#sidebar-splitter {
    width: 1px !important;
    border: 1px var(--chrome-secondary-background-color) !important;
}