.message > .attachments { grid-column: 2; }

.attachment-preview { position: relative; }
.attachment-preview::after {
  content: "Download ↓";
  position: absolute;
  right: 7px;
  bottom: 7px;
  padding: 4px 7px;
  border-radius: 5px;
  background: rgb(0 0 0 / 0.80);
  color: rgb(0 255 255 / 0.96);
  font-size: 10px;
  opacity: 0;
  transition: opacity .15s;
}
.attachment-preview:hover::after { opacity: 1; }
.video-preview::after { display: none; }