Two-Line Firefox Setup

/* Giant Speck's Two-Line Firefox Setup */
/* Version 1.0 - 27 November 2017       */
/* Works in Firefox 57+                 */

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* Reduce width of pinned tabs by reducing the left and right padding */

#TabsToolbar .tab-content[pinned] {
    padding:    0 9px !important;
}

/* Move tabs over to right to make room for address bar */

#TabsToolbar {
    margin:         0 44px 0 40vw !important;
    height:         30px !important;
    padding-left:   5px !important;
}

/* Move address bar to titlebar with tabs */

#nav-bar {
    margin:         -30px 60vw -2px 80px !important;
    height:         29px !important;
    border-bottom:  1px solid #9E9E9E !important;
}

/* URL bar width adjustments */

#urlbar {
    background:     none !important;
    border:         none !important;
    margin-left:    -5px !important;
    min-width:      470px !important;
    font-size:      12px !important;
}

#urlbar:hover {
    background:     none !important;
    border:         none !important;
    box-shadow:     none !important;
}

#urlbar[focused="true"] {
    background:     none !important;
    border:         none !important;
    box-shadow:     none !important;
}

/* Hide bookmark folder icons */

.bookmark-item > .toolbarbutton-icon {
    display:    none !important;
}

/* Increase bookmarks toolbar height */

#PersonalToolbar {
    margin-top: 2px !important;
    height:     28px !important;
    border-top: 1px solid #9E9E9E !important;
}

/* Minor bookmarks toolbar spacing adjustments */

#personal-bookmarks toolbarbutton.bookmark-item, #personal-bookmarks toolbarbutton {
    background:      none !important;
    box-shadow:      none !important;
    margin:          -1px 0px -1px 2px !important;
    padding:         2px 5px 0 5px !important;
    -moz-appearance: none !important; }

#personal-bookmarks toolbarbutton:hover {
    -moz-appearance: none !important;
    background:      none !important;
    text-shadow:     none !important;
    color:           #000 !important;   }

/* Add vibrancy to toolbar, titlebar, and navbar */

#TabsToolbar, #titlebar, #nav-bar {
    -moz-appearance: -moz-mac-vibrancy-light !important;
}


/* Remove line under address bar */

#navigator-toolbox::after{
    content:    none;
}

#nav-bar {
    background: none !important;
    border-bottom: none !important;
}

/* Affix hamburger menu to top right */

#PanelUI-button{
    position:   fixed;
    top:        2px;
    right:      4px;
}

/* Hide titlebar placeholder for caption buttons so that padding between tabs and address bar isn't so ridiculously large */

.titlebar-placeholder[type="caption-buttons"] {
    -moz-box-ordinal-group: 1 !important;
}

/* Give the identity icon some space */

#identity-icon { margin-right: 2px !important;}

/* Customize identity box */

#identity-box-labels {
    font-size: 10px !important;
    text-transform: uppercase !important;
}

/* Customize toolbar icon size */

toolbar .toolbarbutton-1 > .toolbarbutton-icon {
    max-width: calc(2 * var(--toolbarbutton-inner-padding) + 14px) !important;
}

#back-button { margin-left: 4px !important}
#forward-button { margin-right: 8px !important;}

/* Hide Close Buttons in Tabs */

.tab-close-button {display: none !important;}

/* Hide Toolbar Icon Badges */

#PersonalToolbar .toolbarbutton-badge {display: none !important;}

/* Make Toolbar Buttons Grayscale */

.toolbarbutton-1 {filter: grayscale(100%) !important;}