webawesome/src/components/split-panel/split-panel.css

:host {
  --divider-color: var(--wa-color-neutral-border-normal);
  --divider-width: 0.25rem;
  --divider-hit-area: 0.75rem;
  --min: 0%;
  --max: 100%;

  display: grid;
}

.start,
.end {
  overflow: hidden;
}

.divider {
  flex: 0 0 var(--divider-width);
  display: flex;
  position: relative;
  align-items: center;
  justify-content: center;
  background-color: var(--divider-color);
  color: var(--wa-color-neutral-on-normal);
  z-index: 1;
}

.divider:focus {
  outline: none;
}

:host(:not([disabled])) .divider:focus-visible {
  outline: var(--wa-focus-ring);
}

:host([disabled]) .divider {
  cursor: not-allowed;
}

/* Horizontal */
:host(:not([vertical], [disabled])) .divider {
  cursor: col-resize;
}

:host(:not([vertical])) .divider::after {
  display: flex;
  content: '';
  position: absolute;
  height: 100%;
  left: calc(var(--divider-hit-area) / -2 + var(--divider-width) / 2);
  width: var(--divider-hit-area);
}

/* Vertical */
:host([vertical]) {
  flex-direction: column;
}

:host([vertical]:not([disabled])) .divider {
  cursor: row-resize;
}

:host([vertical]) .divider::after {
  content: '';
  position: absolute;
  width: 100%;
  top: calc(var(--divider-hit-area) / -2 + var(--divider-width) / 2);
  height: var(--divider-hit-area);
}

@media (forced-colors: active) {
  .divider {
    outline: solid 1px transparent;
  }
}