metamask-extension/ui/app/css/itcss/components/network.scss

.network-component--disabled {
  border-color: transparent !important;
  cursor: default;

  .fa-caret-down {
    opacity: 0;
  }
}

.network-component.pointer {
  border: 1px solid $shark;
  border-radius: 82px;
  padding: 6px;
  flex: 0 0 auto;

  &.ethereum-network {
    border-color: rgb(3, 135, 137);

    .menu-icon-circle div {
      background-color: rgba(3, 135, 137, .7) !important;
    }
  }

  &.ropsten-test-network {
    border-color: rgb(233, 21, 80);

    .menu-icon-circle div {
      background-color: rgba(233, 21, 80, .7) !important;
    }
  }

  &.kovan-test-network {
    border-color: rgb(105, 4, 150);

    .menu-icon-circle div {
      background-color: rgba(105, 4, 150, .7) !important;
    }
  }

  &.rinkeby-test-network {
    border-color: rgb(235, 179, 63);

    .menu-icon-circle div {
      background-color: rgba(235, 179, 63, .7) !important;
    }
  }
}

.dropdown-menu-item {
  .menu-icon-circle,
  .menu-icon-circle--active {
    margin: 0 14px;
  }
}

.network-indicator {
  display: flex;
  align-items: center;
  font-size: .6em;

  .fa-caret-down {
    line-height: 15px;
    font-size: 12px;
    padding: 0 4px;
  }
}

.network-name {
  line-height: 15px;
  padding: 0 4px;
  font-family: Roboto;
  font-size: 12px;
  flex: 1 0 auto;
}

.network-droppo {
  right: 2px;

  @media screen and (min-width: 576px) {
    right: calc(((100% - 85vw) / 2) + 2px);
  }

  @media screen and (min-width: 769px) {
    right: calc(((100% - 80vw) / 2) + 2px);
  }

  @media screen and (min-width: 1281px) {
    right: calc(((100% - 65vw) / 2) + 2px);
  }
}

.network-name-item {
  font-weight: 100;
  flex: 1 0 auto;
  color: $dusty-gray;
}

.network-check,
.network-check__transparent {
  color: $white;
  margin-left: 7px;
}

.network-check__transparent {
  opacity: 0;
  width: 16px;
  margin: 0;
}

.menu-icon-circle,
.menu-icon-circle--active {
  background: none;
  border-radius: 22px;
  display: flex;
  justify-content: center;
  align-items: center;
  border: 1px solid transparent;
  margin: 0 4px;
}

.menu-icon-circle--active {
  border: 1px solid $white;
  background: rgba(100, 100, 100, .4);
}

.menu-icon-circle div,
.menu-icon-circle--active div {
  height: 12px;
  width: 12px;
  border-radius: 17px;
}

.menu-icon-circle--active div {
  opacity: 1;
}

.network-dropdown-header {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
}

.network-dropdown-divider {
  width: 100%;
  height: 1px;
  margin: 10px 0;
  background-color: $scorpion;
}

.network-dropdown-title {
  height: 25px;
  width: 75px;
  color: $white;
  font-family: Roboto;
  font-size: 18px;
  line-height: 25px;
  text-align: center;
}

.network-dropdown-content {
  height: 36px;
  width: 265px;
  color: $dusty-gray;
  font-family: Roboto;
  font-size: 14px;
  line-height: 18px;
}