A detailed cross-browser and cross-screen-reader compatibility study of the HTML `<details>`/`<summary>` elements. Testing across VoiceOver (macOS/iOS), TalkBack, NVDA, and JAWS reveals significant inconsistencies in how these elements are announced — ranging from minimal info on VoiceOver iOS to verbose announcements in Firefox. Key findings include: marker/triangle removal only affects Firefox screen reader pairings, Safari requires the proprietary `::-webkit-details-marker` pseudo-element to hide the triangle, and find-in-page auto-expansion only works in Chromium browsers. The recommendation is to either test with real users or build a custom disclosure widget with JavaScript and ARIA if consistent behavior is required.
