Answer
CSS variables usually means custom properties whose values can be reused with var(). • Custom property names begin with two hyphens. • They participate in the cascade and normally inherit. • A var() fallback is used only when the referenced custom property is missing or invalid.
💡 Simple Example
:root { --brand: royalblue; }
.button { background: var(--brand, blue); }
⚡ Quick Revision
Custom properties store cascading values that var() can substitute.