metamask-extension/ui/app/components/app/connected-accounts-permissions/index.scss

.connected-accounts-permissions {
  display: flex;
  flex-direction: column;
  font-size: 12px;
  line-height: 17px;
  color: $Grey-500;

  strong {
    font-weight: bold;
  }

  p + p {
    padding-top: 8px;
  }

  &__header {
    display: flex;
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
    cursor: pointer;
    font-size: 14px;
    line-height: 20px;
    color: #24292e;

    button {
      font-size: 16px;
      line-height: 24px;
      background: none;
      padding: 0;
      margin-left: 8px;
    }
  }

  &__list {
    padding-top: 8px;
  }

  &__list-item {
    display: flex;
  }

  & &__checkbox {
    margin: 0 8px 0 0;
    font-size: 18px;
  }

  &__list-container {
    max-height: 0;
    overflow: hidden;
    height: auto;
    transition: max-height 0.8s cubic-bezier(0.4, 0, 0.2, 1);

    &--expanded {
      // arbitrarily set hard coded value for effect to work
      max-height: 100px;
    }
  }
}