gitea/web_src/less/features/dropzone.less

.dropzone {
  border: 2px dashed var(--color-secondary) !important;
  background: none !important;
  box-shadow: none !important;
  padding: 0 !important;
  min-height: 5rem !important;
  border-radius: 4px !important;
}

.dropzone .dz-button {
  color: var(--color-text-light) !important;
}

.dropzone:hover .dz-button {
  color: var(--color-text) !important;
}

.dropzone .dz-error-message {
  top: 145px !important;
}

.dropzone .dz-image {
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  border-radius: 0 !important;
}

.dropzone .dz-image img {
  max-width: 100% !important;
  max-height: 100% !important;
  object-fit: contain !important;
}

.dropzone .dz-preview.dz-image-preview,
.dropzone-attachments .thumbnails img {
  background: transparent !important;
}

.dropzone-attachments .thumbnails img {
  height: 120px !important;
  width: 120px !important;
  object-fit: contain !important;
  margin-bottom: 0 !important;
}

.dropzone .dz-preview:hover .dz-image img {
  filter: opacity(.5) !important;
}