discourse/plugins/chat/assets/stylesheets/common/chat-upload-drop-zone.scss

.chat-upload-drop-zone {
  position: absolute;
  visibility: hidden;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: z("max");
  align-items: center;
  justify-content: center;
  display: flex;
  background: rgba(var(--always-black-rgb), 0.85);

  .uppy-is-drag-over & {
    visibility: visible;
  }

  &__content {
    position: relative;
    width: 50%;
    height: 50%;
  }

  &__background {
    svg {
      transform: scale(0.1);
      transition: transform 200ms ease-in-out;
      height: 80px;

      .uppy-is-drag-over & {
        transform: scale(1);
      }
    }

    position: absolute;
    top: 0;
    left: calc(50% - 100px / 2);
    z-index: 1;
  }

  &__illustration {
    svg {
      transform: scale(0.1);
      transition: transform 200ms ease-in-out;
      height: 80px;

      .uppy-is-drag-over & {
        transform: scale(1);
      }
    }

    position: absolute;
    top: 0;
    left: calc(50% - 100px / 2);
    z-index: 1;
  }

  &__text {
    position: absolute;
    top: 100px;
    left: 0;
    right: 0;
    width: 100%;
    z-index: 1;
    display: flex;
    justify-content: center;

    &__title {
      width: 100%;
      font-weight: 600;
      text-align: center;
      font-size: var(--font-up-2);
      padding-inline: 1rem;
      color: var(--secondary-or-primary);
    }
  }
}