#snowflake {
  position: absolute;   /* overlay the whole page */
  top: 0;
  left: 0;
  width: 100%;          /* match page width */
  height: auto;         /* JS sets actual height */
  pointer-events: none; /* don’t block clicks */
  z-index: 9999;        /* sit above content */
}
.snow-line {
  position: absolute;
  height: 2px;
  background: white;
  opacity: 1;
  transition: opacity 5s linear;
}
/* Generic invisible hitbox */
.snowflake-block,
.snowflake-complete-block {
  display: inline-block;   /* size matches content by default */
}