This example demonstrates how to build both a color legend and a size legend using D3.js v5. The color legend maps ordinal categories (Apple, Lemon, Lime, Orange) to distinct colors via `scaleOrdinal`, while the size legend uses `scaleSqrt` to represent numerical values from 0 to 10 as circle radii. Both legends implement a general update pattern with `selection.merge()` for enter and exit transitions, rendering circles and text labels in SVG. The ticks for the size legend are generated using `sizeScale.ticks()`, with all elements styled via CSS classes.