Originalecken in den Tabs statt Gausskurven

.tabmail-tab {
margin: 2px 0px !important;
}




.tab-background {
background-image: none !important;
border: 1px solid threedshadow !important;
border-bottom: none !important;
border-top-left-radius: 4px !important;
border-top-right-radius: 4px !important;
-moz-margin-start: 0px !important;
-moz-margin-end: 2px !important;
background-color: threeDshadow !important;
background-image: -moz-linear-gradient(rgba(255,255,255,0.35) 25%, rgba(255,255,255,0)) !important;
}




.tabmail-tab:not([selected]):not(:hover) +
.tabmail-tab:not([selected]):not(:hover)::before,
.tabmail-tab:last-child:not([selected]):not(:hover)::after {
background: none !important;
}




.tabmail-tab:hover .tab-background,
.tabmail-tab[selected] .tab-background {
background: -moz-dialog !important;
background-image: -moz-linear-gradient(rgba(255,255,255,0.35) 25%, rgba(255,255,255,0)) !important;
}




.tabmail-tab:hover .tab-text,
.tabmail-tab[selected] .tab-text {
color: black !important;
opacity: 1 !important;
}




.tabmail-tab:last-child:not([selected]):not(:hover)::after {
-moz-margin-start: 0px;
-moz-margin-end: 2px;
}







.tab-background-middle[selected=true] {
  background-clip: padding-box, padding-box, content-box;
  background-color: var(--fgTabBackgroundColor);
  background-image: none !important;
  background-repeat: repeat-x;
  background-size: auto 100%;
  /* The padding-top combined with background-clip: content-box
     (the bottom-most) ensure the background-color doesn't extend
     above the top border. */
  padding-top: 2px;
}




.tab-background-start[selected=true]::after,
.tab-background-start[selected=true]::before,
.tab-background-start,
.tab-background-end,
.tab-background-end[selected=true]::after,
.tab-background-end[selected=true]::before {
  min-height: auto !important;
  width: auto !important;
}




/* Lässt die unschönen Ecken gänzlich verschwinden */




.tab-background-start[selected=true]:-moz-locale-dir(ltr):not(:-moz-lwtheme)::before,
.tab-background-end[selected=true]:-moz-locale-dir(rtl):not(:-moz-lwtheme)::before {
  background-image: none !important;
  background-size: 100% 100%;
}




.tab-background-end[selected=true]:-moz-locale-dir(ltr):not(:-moz-lwtheme)::before,
.tab-background-start[selected=true]:-moz-locale-dir(rtl):not(:-moz-lwtheme)::before {
  background-image: none !important;
  background-size: 100% 100%;
}