#characters {
  display: grid;
  grid-template-columns: repeat(10, 1fr); /* 10 equal flexible columns */
  gap: 10px;
}

#characters > div {
  display: flex;
  justify-content: center;
  align-items: center;
}

#characters img {
  width: 100%;      /* scale to fit cell */
  max-width: 100px; /* prevent it from growing too big */
  height: auto;     /* keep aspect ratio */
  display: block;
}

#addchars{
  text-align: center;
  width: 410px;
  margin: auto;
  margin-top: 30px;
  background: green;
  display: none;
  border-radius: 10px;
  padding: 10px;
  cursor: pointer;
}
#addchars span{
  font-weight: bold;
}