@@ -503,81 +503,6 @@ Overflow in Print and Other Static Media</h3>
503503 for example, e-book readers paginate content,
504504 but are interactive.
505505
506- <h3 id="scrollbar-layout">
507- Scrollbars and Layout</h3>
508-
509- When reserving space for a scrollar placed at the edge of an element's box,
510- the reserved space is inserted between the inner border edge
511- and the outer padding edge.
512- For the purpose of the <a spec=css-backgrounds>background positioning area</a> and <a spec=css-backgrounds>background painting area</a> however,
513- this reserved space is considered to be part of the [=padding box=] .
514-
515- <div class="example">
516- In the following document fragment,
517- both an absolutely-positioned element
518- and a background image
519- are positioned to the top right of the box.
520-
521- <xmp highlight=html>
522- <style>
523- article {
524- background: top right no-repeat url(circle.png);
525- position: relative;
526- overflow: auto; }
527- aside { position: absolute; top: 0; right: 0; }
528- </style>
529- <article>
530- <aside> ×</aside>
531- </article>
532- </xmp>
533-
534- If no scrollbars are present on <code> <article></code> ,
535- they will both coincide in the top right padding edge corner.
536- However, if scrollbars are present
537- then <code> <aside></code> will be completely visible,
538- on the right padding-box edge adjacent to the scrollbars;
539- whereas the background image will be tucked underneath the scrollbars,
540- in the top right corner of the scrollbar-extended <a spec=css-backgrounds>background positioning area</a> .
541- </div>
542-
543- When the box is intrinsically sized,
544- this reserved space is added to the size of its contents.
545- It is otherwise subtracted from space alotted to the [=content area=] .
546- To the extent that the presence of scrollbars can affect sizing,
547- UAs must start with the assumption that no scrollbars are needed,
548- and recalculate sizes if it turns out they are.
549-
550- <div class="example">
551- In the following document fragment,
552- the outer <code> <article></code> has ''height: auto'' , but ''max-height: 5em'' .
553- The inner <code> <section></code> has large margins and would normally just fit:
554-
555- <xmp highlight=html>
556- ...
557- article { overflow: auto; max-height: 5em; width: max-content; }
558- section { margin: 2em; line-height: 1 }
559- ...
560- <article>
561- <section>
562- This section has big margins.
563- </section>
564- </article>
565- </xmp>
566-
567- If we assumed that <code> <article></code> needed scrollbars,
568- then the height of <code> <section></code> ,
569- including the single line of text and twice 2em of margins,
570- adds up to 5em plus a scrollbar.
571- Since that is greater than 5em, the maximum allowed height,
572- it seems we made the right assumption and d1 indeed needs scrollbars.
573-
574- However, we should have started by assuming that no scrollbars are needed.
575- In that case the content height of <code> <article></code>
576- is exactly the maximum height of 5em,
577- proving that the assumption was correct
578- and <code> <article></code> indeed should not have scrollbars.
579- </div>
580-
581506<h3 id="scrolling-direction">
582507Scrolling Origin, Direction, and Restriction</h3>
583508
@@ -744,8 +669,86 @@ Smooth Scrolling: the 'scroll-behavior' Property</h3>
744669
745670 User agents may ignore this property. <!--fingerprint-->
746671
747- <h2 id="scrollbar-gutter-property">
748- Reserving space for the scrollbar: the 'scrollbar-gutter' property</h2>
672+ <h2 id="scrollbar-layout">
673+ Scrollbars and Layout</h2>
674+
675+ <h3 id="scrollbar-sizing">
676+ Reserving Space for the Scrollbar</h3>
677+
678+ When reserving space for a scrollar placed at the edge of an element's box,
679+ the reserved space is inserted between the inner border edge
680+ and the outer padding edge.
681+ For the purpose of the <a spec=css-backgrounds>background positioning area</a> and <a spec=css-backgrounds>background painting area</a> however,
682+ this reserved space is considered to be part of the [=padding box=] .
683+
684+ <div class="example">
685+ In the following document fragment,
686+ both an absolutely-positioned element
687+ and a background image
688+ are positioned to the top right of the box.
689+
690+ <xmp highlight=html>
691+ <style>
692+ article {
693+ background: top right no-repeat url(circle.png);
694+ position: relative;
695+ overflow: auto; }
696+ aside { position: absolute; top: 0; right: 0; }
697+ </style>
698+ <article>
699+ <aside> ×</aside>
700+ </article>
701+ </xmp>
702+
703+ If no scrollbars are present on <code> <article></code> ,
704+ they will both coincide in the top right padding edge corner.
705+ However, if scrollbars are present
706+ then <code> <aside></code> will be completely visible,
707+ on the right padding-box edge adjacent to the scrollbars;
708+ whereas the background image will be tucked underneath the scrollbars,
709+ in the top right corner of the scrollbar-extended <a spec=css-backgrounds>background positioning area</a> .
710+ </div>
711+
712+ When the box is intrinsically sized,
713+ this reserved space is added to the size of its contents.
714+ It is otherwise subtracted from space alotted to the [=content area=] .
715+ To the extent that the presence of scrollbars can affect sizing,
716+ UAs must start with the assumption that no scrollbars are needed,
717+ and recalculate sizes if it turns out they are.
718+
719+ <div class="example">
720+ In the following document fragment,
721+ the outer <code> <article></code> has ''height: auto'' , but ''max-height: 5em'' .
722+ The inner <code> <section></code> has large margins and would normally just fit:
723+
724+ <xmp highlight=html>
725+ ...
726+ article { overflow: auto; max-height: 5em; width: max-content; }
727+ section { margin: 2em; line-height: 1 }
728+ ...
729+ <article>
730+ <section>
731+ This section has big margins.
732+ </section>
733+ </article>
734+ </xmp>
735+
736+ If we assumed that <code> <article></code> needed scrollbars,
737+ then the height of <code> <section></code> ,
738+ including the single line of text and twice 2em of margins,
739+ adds up to 5em plus a scrollbar.
740+ Since that is greater than 5em, the maximum allowed height,
741+ it seems we made the right assumption and d1 indeed needs scrollbars.
742+
743+ However, we should have started by assuming that no scrollbars are needed.
744+ In that case the content height of <code> <article></code>
745+ is exactly the maximum height of 5em,
746+ proving that the assumption was correct
747+ and <code> <article></code> indeed should not have scrollbars.
748+ </div>
749+
750+ <h3 id="scrollbar-gutter-property">
751+ Reserving space for the scrollbar: the 'scrollbar-gutter' property</h3>
749752
750753 The space between the inner border edge and the outer padding edge
751754 which user agents may reserve to display the scrollbar
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