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+- Fixed-positioned `EuiHeader`s now set a global CSS `--euiFixedHeadersOffset` variable, which updates dynamically based on the number of fixed headers on the page.
+- `EuiFlyout`s now dynamically set their position, height, and mask based on the number of fixed headers on the page.
+- Sticky-positioned `EuiPageSidebar`s now dynamically set their position and height based on the number of fixed headers on the page. This can still be overridden via the `sticky.offset` prop if needed.
+- `EuiPageTemplate` now dynamically offsets content from any fixed headers on the page. This can still be overridden via the `offset` prop if needed.
+
+**Deprecations**
+
+- Deprecated the Sass `euiHeaderAffordForFixed` mixin. Use the new global CSS `var(--euiFixedHeadersOffset)` variable instead.