opencode-ide-plugin/packages/ui/src/components/resize-handle.css

[data-component="resize-handle"] {
	position: absolute;
	z-index: 10;

	&::after {
		content: "";
		position: absolute;
		opacity: 0;
		transition-property: opacity;
		transition-duration: var(--transition-duration);
		transition-timing-function: var(--transition-easing);
	}

	&:hover::after,
	&:active::after {
		opacity: 1;
	}

	&[data-direction="horizontal"] {
		inset-block: 0;
		inset-inline-end: 0;
		width: 8px;
		transform: translateX(50%);
		cursor: col-resize;

		&[data-edge="start"] {
			inset-inline-start: 0;
			inset-inline-end: auto;
			transform: translateX(-50%);
		}

		&::after {
			width: 3px;
			inset-block: 0;
			inset-inline-start: 50%;
			transform: translateX(-50%);
		}
	}

	&[data-direction="vertical"] {
		inset-inline: 0;
		inset-block-start: 0;
		height: 8px;
		transform: translateY(-50%);
		cursor: row-resize;

		&[data-edge="end"] {
			inset-block-start: auto;
			inset-block-end: 0;
			transform: translateY(50%);
		}

		&::after {
			height: 3px;
			inset-inline: 0;
			inset-block-start: 50%;
			transform: translateY(-50%);
		}
	}
}