.play-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 30px;
  height: 30px;
  margin-right: 12px;
  vertical-align: middle;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--card);
  color: var(--red);
  font-size: 11px;
  line-height: 1;
  cursor: pointer;
  transition: border-color .18s ease, background .18s ease, color .18s ease;
}

.play-btn:hover { border-color: var(--red); }
.play-btn.on { background: var(--red); border-color: var(--red); color: #fff; }