/* Explanation annotation system */
.explain {
  cursor: help;
  position: relative;
  display: inline;
}

.explain-term {
  border-bottom: 1.5px dotted var(--text-accent);
  padding-bottom: 1px;
  transition: background var(--transition-speed) ease;
}

.explain:hover .explain-term,
.explain:focus .explain-term {
  background: var(--glow-color);
}

/* Popover */
.explain-popover {
  position: absolute;
  z-index: 200;
  left: 50%;
  transform: translateX(-50%);
  top: calc(100% + 8px);
  max-width: 360px;
  min-width: 200px;
  padding: 14px 18px;
  background: var(--bg-secondary);
  border: var(--border-width) solid var(--border-accent);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-card);
  backdrop-filter: blur(var(--blur-amount));
  -webkit-backdrop-filter: blur(var(--blur-amount));
  font-size: 0.88rem;
  line-height: 1.6;
  color: var(--text-secondary);
  opacity: 0;
  pointer-events: none;
  transition: opacity 150ms ease;
}

.explain-popover.visible {
  opacity: 1;
  pointer-events: auto;
}

/* Arrow */
.explain-popover::before {
  content: '';
  position: absolute;
  top: -6px;
  left: 50%;
  transform: translateX(-50%) rotate(45deg);
  width: 10px;
  height: 10px;
  background: var(--bg-secondary);
  border-top: var(--border-width) solid var(--border-accent);
  border-left: var(--border-width) solid var(--border-accent);
}

/* Flip above when near bottom */
.explain-popover.above {
  top: auto;
  bottom: calc(100% + 8px);
}
.explain-popover.above::before {
  top: auto;
  bottom: -6px;
  border-top: none;
  border-left: none;
  border-bottom: var(--border-width) solid var(--border-accent);
  border-right: var(--border-width) solid var(--border-accent);
}

.explain-popover code {
  font-size: 0.85em;
}