Not enough light

What's happening

Golden Pothos earns its variegation from good light; the creamy-yellow patches have no chlorophyll, so in dim conditions the plant reverts to plain green to capture what little light there is. Low light also makes the vines stretch toward the window with long gaps between small leaves, a habit called legginess.

How to fix it

Move the plant to a brighter spot with plenty of bright, indirect light — a few feet back from an east or north window, or filtered south/west light. If your space is genuinely dim, a full-spectrum grow light makes a real difference and is often the only way to bring the variegation back. Note that already-greened leaves usually stay green, but new growth in better light will return marbled and compact.

This is general guidance based on common symptoms; individual plants vary.