This page demonstrates how browsers give embedded iframe documents an opaque or transparent canvas depending on the combination of colour schemes determined for the documents.
Embedded content with a background colour that doesn't match the container's background colour demonstrates the browser applying an opaque background canvas with a default colour appropriate for the colour scheme applied to the document.
This column should always display with a light background. It expresses support only for a light scheme.
This column should always display with a dark background. It expresses support only for a dark scheme.
This column should display with a background matching user preference, defaulting to light.
This column should display with a light blue background. No support is expressed for any colour scheme.