Preparing for Entra ID Company Branding CSS Changes

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Why Is Microsoft Retiring Custom CSS Positioning?

Entra ID company branding just lost a customization option, by design. Microsoft is retiring support for custom CSS positioning properties—such as transform, clip-path, and opacity—within Microsoft Entra company branding configurations.

This change directly addresses cybersecurity concerns. Threat actors have historically manipulated positioning properties and transparent overlays to build convincing, malicious sign-in look-alikes. By enforcing strict layout rules, Microsoft is closing that phishing vector across all tenants.

While new additions stopped working in July 2026, existing CSS customizations will continue rendering until October 2026, when support ends completely with no migration path.

The Impact on Custom Sign-In Experiences

This update affects any organization utilizing a custom-branded sign-in page, regardless of industry. Understanding the layout fallback behavior is critical for maintaining professional brand consistency:

  • Default placement fallback: Custom elements using prohibited CSS will not disappear completely; instead, they automatically revert to Microsoft’s default layout placement.
  • Visual degradation risks: Custom-designed sign-in portals can visually shift into mismatched, generic layouts without prior warning to end users.
  • Security vs. brand alignment: While security operations teams welcome this change as an anti-phishing win, corporate communications and brand managers may face unexpected layout shifts if templates are unmanaged.

Action Items Before the October Cutover

To prevent broken sign-in portals across your enterprise, IT and identity teams should take three proactive measures:

  • Inventory CSS templates: Review every custom CSS property currently deployed in your tenant’s company branding settings.
  • Test rendering behavior: Preview how sign-in pages render once positional properties revert to default placements.
  • Redesign layout elements: Rebuild custom branding assets to align with native Entra ID styling guidelines before October 2026.

A broken sign-in page creates a poor first impression for employees, new hires, and external partners. After October, no CSS fallback remains to catch broken positioning.

How we help you navigate this change:

  • Branding Audit: We analyze your active Entra ID sign-in templates to spot prohibited CSS positioning rules.
  • Layout Remediation: We help re-architect your company branding using supported, compliant design elements.
  • Cross-Team Alignment: We bridge technical security requirements with your brand standards to keep sign-in pages secure and professional.
Graphic with text: Entra ID Company Branding: CSS Retirement by Oct 2026. Simple SharePoint, a division of Rego Consulting.

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