.postcard-text {
  background-color: rgba(200,200,200,0.2);
  border: none;
  outline: none;
  resize: none;
  padding: 0;              /* no extra space */
  line-height: 1;          /* matches font size */
  height: auto;            /* grows with content */
}
.postcard-text.filled {
  background-color: transparent; /* disappears once typed */
}