.display-container {
  border: 1px solid #ccc;
  border-radius: 5px;
  padding: 20px;
}

.binary-tree {
/*  width: fit-content; */
}

.binary-tree div {                /* null node */
  display: grid;
  grid-template-columns: 1fr 1fr; /* L and R children */
  grid-template-rows: auto 1fr;   /* data above, tree below */
  gap: 0.5rem;
  position: relative;                /* relative to the span (?) */
  margin-bottom: 1rem;               /* vertical separation between nodes */
}

/* Hide binary trees by default */
.binary-tree {
  display: none;
}

/* Show the active binary trees */
.binary-tree.active {
  display: grid;
}

.binary-tree span {    /* the node itself, with the data */
  grid-column: 1 / 3;  /* occupy both columns */
  border: 1px solid;
  width: 9rem;
  height: 4rem;
  border-radius: 25%;
  display: grid;       /* center the content */
  place-items: center;
  text-align: center;
  margin: auto auto;   /* distributes nodes horizontally */
}

.binary-tree span::after {
  content: "";              /* to be visible */
  position: absolute;       /* position relative to the div, not the span */
  width: 50%;
  height: 1.5rem;           /* margin-bottom + gap */
  left: 50%;
  bottom: 0;
  transform: translateY(100%);
  background: linear-gradient(to top right, #0000 49%, #000 0 51%, #0000 0);
}

.binary-tree :nth-child(2) > span::after {
  left: auto;
  right: 50%;
  background: linear-gradient(to top left, #0000 49%, #000 0 51%, #0000 0);
}

.binary-tree > div > span::after {
  content: none;
}

.binary-tree.ext > div:first-child > span {
  background: #666666;
  color: white;
}

/* Basic button styling */
.controls {
  display: flex;
  gap: 10px;
  margin-bottom: 10px;
}

.binary-tree .tab-btn {
  background: #ddd;
  cursor: pointer;
}

.binary-tree .tab-btn.active {
  background: #666666;
  color: white;
}

/* display containers */
.banner {
  position: sticky;
  text-align: center;
  color: black;
  top: 0;
  right: 0;
  left: 0;
  z-index: 999;
}

.family-grid {
  display: grid;
  grid-template-rows: auto auto auto;
  background-color: Gainsboro;
  gap: 8px;
  padding: 8px;
  margin: 4px;
  border: 1px solid black;
  border-radius: 8px;

}

.root-row {
  display: grid;
  align-items: center;
  justify-items: stretch;
  background-color: White;
  padding: 10px 10px 10px 10px;  /* between content and border */
  border: 1px solid black;
  border-radius: 8px;
  margin: 0 0 10px 0;  /* outside the border */
}

.extension-row {
  display: grid;
  align-content: center;
  background-color: White;
  padding: 10px 10px 10px 10px;  /* between content and border */
  border: 1px solid black;
  border-radius: 8px;
  margin: 0 0 10px 0;  /* outside the border */
}

.dot {
  height: 25px;
  width: 25px;
  background-color: blue;
  border-radius: 50%;
  border: 1px solid black;
  display: inline-block;
}