Lightningbeam/src/jsMenus.css

html, body {
	margin: 0;
	height: 100%;
}
body { display: flex; flex-direction: column }
.menubar { flex: 0 0 22px }
div.below-menubar { flex: 1 1 0; min-height: 0;}

.menu-item > [role=button] {
    display: flex;
    width: 100%;
    border: none;
    padding: 0px;
    color: inherit;
    background-color: inherit;
    appearance: none;
    outline: none;
}

.nwjs-menu {
	font-family: 'Helvetica Neue', HelveticaNeue, 'TeX Gyre Heros', TeXGyreHeros, FreeSans, 'Nimbus Sans L', 'Liberation Sans', Arimo, Helvetica, Arial, sans-serif;
	font-size: 14px;
	color: #2c2c2c;
	-webkit-user-select: none;
	user-select: none;
	-webkit-font-smoothing: subpixel-antialiased;
	font-weight: 400;
        white-space: pre;
}

.contextmenu {
	min-width: 100px;
	background-color: #fafafa;
	position: fixed;
	opacity: 0;
	transition: opacity 250ms;
	margin: 0;
	padding: 0 0;
	list-style: none;
	pointer-events: none;
	border: 1px rgba(191, 191, 191, 0.8) solid;
	border-radius: 4px;
	box-shadow: rgba(43, 43, 43, 0.34) 1px 1px 11px 0px;
	z-index: 2147483647;
}

.contextmenu {
	opacity: 1;
	transition: opacity 30ms;
	pointer-events: all;
}

.contextmenu.submenu {
    transition: opacity 250ms;
}

.contextmenu.submenu {
	transition: opacity 150ms;
	transition-timing-function: step-end;
}

.menu-item.normal,
.menu-item.checkbox,
.menu-item.radio {
	cursor: default;
	margin: 2px 0;
	padding: 0 0;
	box-sizing: border-box;
	position: relative;
	display: flex;
	flex-direction: row;
	flex-wrap: nowrap;
	justify-content: flex-start;
	align-content: stretch;
	align-items: flex-start;
	width: 100%;
}

.contextmenu .menu-item.active,
.menu-item.normal.submenu-active, .menu-item.normal.submenu-active:hover {
	background-color: #499BFE;
	color: #fff;
}
.menu-item:hover { background-color: inherit; }

.menu-item.normal > div,
.menu-item.checkbox > div,
.menu-item.radio > div {
    align-self: center;
    vertical-align: middle;
    display: inline-flex;
    justify-content: flex-start;
    flex-shrink: 0;
}

.menu-item.normal .icon {
    display: inline-flex;
    vertical-align: middle;
    max-width: 16px;
    max-height: 16px;
    align-self: center;
}

li.menu-item.separator {
	height: 2px;
	background-color: rgba(128, 128, 128, 0.2);
	margin: 5px 0;
}

.menu-item .modifiers,
.menu-item .keys,
.menu-item .icon-wrap,
.menu-item .checkmark {
	display: inline-flex;
	align-items: center;
	vertical-align: middle;
}

.menu-item .keys {
    opacity: 0.4;
}

.menu-item .checkmark {
	width: 22px;
}
.menu-item > [role=button] > .modifiers,
.menu-item > [role=button] > .keys {
    box-sizing: border-box;
    padding: 0 6px;
    text-align: right;
    order: 0;
    flex: 0 0 auto;
    align-self: center;
}

.menu-item > [role=button] > .label {
    padding: 0 22px 0 0;
    order: 0;
    flex: 1 0 auto;
    align-self: center;
    text-align: left;
}

.menu-item.disabled,
.menu-item.disabled:hover,
.contextmenu .menu-item.disabled:hover {
    color: #ababab;
}

.menu-item.disabled:hover,
.contextmenu .menu-item.disabled:hover {
    background-color: transparent;
}

.menu-item .icon-wrap {
    padding: 0 6px 0 0;
    display: inline-flex;
    align-self: center;
}

.menu-item .label-text {
    align-items: center;
    vertical-align: middle;
}

.menu-item.checkbox.checked .checkmark::before {
	content: '✔';
	text-align: center;
	width: 100%;
}

.menu-item.radio.checked .checkmark::before {
	content: '⊚';
	text-align: center;
	width: 100%;
}

.menubar {
	height: 22px;
	margin: 0;
	padding: 0;
	top: 0;
	left: 0;
	right: 0;
	background-color: #eee;
	z-index: 2147483647;
}

.menubar > .menu-item.normal {
    display: inline-block;
    width: auto;
    height: 100%;
}

.menubar .menu-item.normal > div {
    vertical-align: top;
}
.menubar > .menu-item {
    margin: 0 4px 0 0;
}
.menubar > .menu-item.normal .checkmark,
.menubar > .menu-item.normal .modifiers {
    display: none;
}

.menubar .menu-item.normal .label {
    padding: 0 3px;
}

.contextmenu.menubar-submenu {
    transition: opacity 0ms;
}

/* Mac only?
.contextmenu {
    border-radius: 7px;
}
.contextmenu.menubar-submenu {
    border-radius: 0 0 7px 7px;
}
*/