purescript_web_ext/extension/sidebar.css

html, body {
  width: 100%;
}

#tabs {
  margin-top: 1px;
  width: 100%;
}

.tab {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  border: solid #cfcfcf 1px;
  margin-bottom: 1px;
  padding-left: 2px;
  padding-bottom: 2px;
  width: 100%;
}

.tab.active {
  background-color: #d4f2fc;
}

.tab:hover {
  background-color: #cccccc;
}

.tab.active:hover {
  background-color: #b2dceb;
}

.tab-title {
  display: inline-block;
  align-self: center;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  width: 100%;
}

.tab-favicon {
  /* necessary to avoid flicker when hovering the close button */
  flex-shrink: 0;
  display: inline-block;
  background-size: cover;
  background-position: center;
  width: 15px;
  height: 15px;
  margin-left: 5px;
  margin-right: 5px;
  vertical-align: middle;
}

.close-button-parent {
  width: 17px;
  height: 17px;
  margin-right: 4px;
  display: none;
}

.tab:hover > .close-button-parent {
  display: inline-block;
}

.close-button-parent:hover {
  background-color: #707070;
}

.close-button-outer {
  height: 15px;
  width: 2px;
  margin-left: 6.2px;
  margin-top: 1.2px;
  background-color: black;
  transform: rotate(45deg);
  Z-index: 1;
}

.close-button-inner {
  height: 15px;
  width: 2px;
  background-color: black;
  transform: rotate(90deg);
  Z-index: 2;
}

.close-button-parent:hover .close-button-outer {
  background-color: #cccccc;
}
.close-button-parent:hover .close-button-inner {
  background-color: #cccccc;
}