Thunderbird chrome (Ubuntu 16.10)

userChrome.css

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

#msgHeaderView {
    border-bottom: 0 !important;
}

#folderPaneBox {
    padding-top: 1em;
    border: 0 !important;    
}

#calendar-nav-control {
    padding-top: 1em;
    padding-right: 1em;
}

#quick-filter-bar-main-bar {
    padding: .4em;
    padding-top: .5em;
    border: 0 !important;
    border-bottom: 0 !important;
}

#attachmentView {
    -moz-appearance: none;
    min-height: 48px;
    overflow: auto;
}

#folderTree > treechildren, #folderTree > treechildren::-moz-tree-row {
    background-color: #F5F5F5 !important;
}

#folderTree > treechildren::-moz-tree-cell-text {
    font-size: 10pt !important; }

#threadTree > treechildren::-moz-tree-cell-text {
    font-size: 10.5pt;
}

#threadTree > treechildren::-moz-tree-row {
    border-bottom: 1px dotted #e1e1e1 !important;
    min-height: 1.5em !important;
}

#folderTree treechildren::-moz-tree-row(selected),
#folderTree treechildren::-moz-tree-row(selected, focus) {
    background-color: Highlight !important;
}

/* stop attachment filename being truncated */
.attachmentBox {
    width: auto;
    max-width: none;
    min-width: 15em;
}

/* hide status toolbar panel borders */
statusbarpanel, .calendar-sidebar-splitter {
    -moz-appearance: none;
    border-top: 0 !important;
}

/* decrease thickness of pane splitters */
#folderpane_splitter, #dirTree-splitter, #sidebar-splitter, #threadpane-splitter,
#results-splitter, #compose-toolbar-sizer, #attachment-splitter,
#additionalFolderPaneSplitter, #threadpane-splitter, #today-pane-splitter,
#calendarDisplayDeck {
    border: 0 !important;
    border-right: 0 !important;
    border-left: 0 !important;
}

#calendar-toolbar-deck, #today-pane-panel > sidebarheader, .mail-toolbox,
#calsidebar_splitter {
    display: none;
}