title is h1 class "heading title", sized above h1

html & epub (share css): with <h0> gone the title became <h1>. The title
now carries class "heading title", and each stylesheet's h0 rules are
h1.title rules with the same values; h0 leaves the grouped selectors,
being emitted by nothing. In html the title looks as it did.

(assisted by Claude-Code)

4 files changed, 68 insertions, 44 deletions

diff --git a/org/out_xmls.org b/org/out_xmls.org
index 852fcf6..9ea8260 100644
--- a/org/out_xmls.org
+++ b/org/out_xmls.org
@@ -343,6 +343,18 @@ int _heading_element_level(O)(O obj, string _xml_type) {
   if (_lev < 1) { return 1; }
   return (_lev > 6) ? 6 : _lev;
 }
+/+ ↓ the class a heading carries. The title (level A) shares <h1> with level B,
+     having no element of its own since bespoke <h0> is not recognized and no
+     longer used, so it is told apart by class: "heading title", which the
+     stylesheets size a step above h1, as h0 was. Shifting every level down one
+     instead would give the title alone h1, and would further compress the
+     limited html heading range (h1 - h6).
++/
+string _heading_class(O)(O obj) {
+  return (obj.metainfo.heading_lev_markup == 0)
+    ? obj.metainfo.is_a ~ " title"
+    : obj.metainfo.is_a;
+}
 #+END_SRC
 
 **** anchor tags
@@ -1208,7 +1220,7 @@ string heading(O,M)(
           ? "" : ((obj.metainfo.object_number.empty)
             ? "" : obj.metainfo.identifier),
         _heading_element_level(obj, _xml_type),
-        obj.metainfo.is_a,
+        _heading_class(obj),
         obj.metainfo.identifier,
         tags,
         heading_lev_anchor_tag,
@@ -1224,7 +1236,7 @@ string heading(O,M)(
   </div>┃",
         _horizontal_rule,
         _heading_element_level(obj, _xml_type),
-        obj.metainfo.is_a,
+        _heading_class(obj),
         tags,
         heading_lev_anchor_tag,
         _txt,
diff --git a/org/out_xmls_css.org b/org/out_xmls_css.org
index ae361c0..4a7eccf 100644
--- a/org/out_xmls_css.org
+++ b/org/out_xmls_css.org
@@ -382,7 +382,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -704,7 +704,7 @@ ul { }
 
 #+NAME: css_light_shared_headings
 #+BEGIN_SRC css
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -715,7 +715,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.85rem; }
+h1.title { font-size       : 1.85rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -723,7 +723,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #808080;
 }
 h1.i { margin-left         : 2em; }
@@ -740,7 +740,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.85rem;
   line-height              : 150%%;
@@ -1341,7 +1341,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -1653,7 +1653,7 @@ ul { }
 
 #+NAME: css_dark_shared_headings
 #+BEGIN_SRC css
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -1664,7 +1664,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.9rem; }
+h1.title { font-size       : 1.9rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -1672,7 +1672,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #999999;
 }
 h1.i { margin-left         : 2em; }
@@ -1689,7 +1689,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.8rem;
   line-height              : 150%%;
diff --git a/src/sisudoc/outputs/io_out/xmls.d b/src/sisudoc/outputs/io_out/xmls.d
index aba0e4f..b6001ea 100644
--- a/src/sisudoc/outputs/io_out/xmls.d
+++ b/src/sisudoc/outputs/io_out/xmls.d
@@ -236,6 +236,18 @@ template outputXHTMLs() {
       if (_lev < 1) { return 1; }
       return (_lev > 6) ? 6 : _lev;
     }
+    /+ ↓ the class a heading carries. The title (level A) shares <h1> with level B,
+         having no element of its own since bespoke <h0> is not recognized and no
+         longer used, so it is told apart by class: "heading title", which the
+         stylesheets size a step above h1, as h0 was. Shifting every level down one
+         instead would give the title alone h1, and would further compress the
+         limited html heading range (h1 - h6).
+    +/
+    string _heading_class(O)(O obj) {
+      return (obj.metainfo.heading_lev_markup == 0)
+        ? obj.metainfo.is_a ~ " title"
+        : obj.metainfo.is_a;
+    }
     /+ ↓ the anchors an object carries.
          "name" on an <a> is obsolete; "id" is what a link target is. The
          two are not interchangeable here, because these tags are not all
@@ -983,7 +995,7 @@ string tail(M)(M doc_matters) {
               ? "" : ((obj.metainfo.object_number.empty)
                 ? "" : obj.metainfo.identifier),
             _heading_element_level(obj, _xml_type),
-            obj.metainfo.is_a,
+            _heading_class(obj),
             obj.metainfo.identifier,
             tags,
             heading_lev_anchor_tag,
@@ -999,7 +1011,7 @@ string tail(M)(M doc_matters) {
       </div>┃",
             _horizontal_rule,
             _heading_element_level(obj, _xml_type),
-            obj.metainfo.is_a,
+            _heading_class(obj),
             tags,
             heading_lev_anchor_tag,
             _txt,
diff --git a/src/sisudoc/outputs/io_out/xmls_css.d b/src/sisudoc/outputs/io_out/xmls_css.d
index 6cab68e..1d44c5c 100644
--- a/src/sisudoc/outputs/io_out/xmls_css.d
+++ b/src/sisudoc/outputs/io_out/xmls_css.d
@@ -649,7 +649,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -935,7 +935,7 @@ ul, li {
 }
 li { }   /* bullets are rendered as text; the background image was never shipped */
 ul { }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -946,7 +946,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.85rem; }
+h1.title { font-size       : 1.85rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -954,7 +954,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #808080;
 }
 h1.i { margin-left         : 2em; }
@@ -971,7 +971,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.85rem;
   line-height              : 150%%;
@@ -1465,7 +1465,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -1741,7 +1741,7 @@ ul, li {
 }
 li { }   /* bullets are rendered as text; the background image was never shipped */
 ul { }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -1752,7 +1752,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.9rem; }
+h1.title { font-size       : 1.9rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -1760,7 +1760,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #999999;
 }
 h1.i { margin-left         : 2em; }
@@ -1777,7 +1777,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.8rem;
   line-height              : 150%%;
@@ -2272,7 +2272,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -2558,7 +2558,7 @@ ul, li {
 }
 li { }   /* bullets are rendered as text; the background image was never shipped */
 ul { }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -2569,7 +2569,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.85rem; }
+h1.title { font-size       : 1.85rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -2577,7 +2577,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #808080;
 }
 h1.i { margin-left         : 2em; }
@@ -2594,7 +2594,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.85rem;
   line-height              : 150%%;
@@ -3014,7 +3014,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -3290,7 +3290,7 @@ ul, li {
 }
 li { }   /* bullets are rendered as text; the background image was never shipped */
 ul { }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -3301,7 +3301,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.9rem; }
+h1.title { font-size       : 1.9rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -3309,7 +3309,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #999999;
 }
 h1.i { margin-left         : 2em; }
@@ -3326,7 +3326,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.8rem;
   line-height              : 150%%;
@@ -3747,7 +3747,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -4033,7 +4033,7 @@ ul, li {
 }
 li { }   /* bullets are rendered as text; the background image was never shipped */
 ul { }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -4044,7 +4044,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.85rem; }
+h1.title { font-size       : 1.85rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -4052,7 +4052,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #808080;
 }
 h1.i { margin-left         : 2em; }
@@ -4069,7 +4069,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.85rem;
   line-height              : 150%%;
@@ -4329,7 +4329,7 @@ nav#toc ol {
   padding-left             : 0em;
   text-indent              : 0em;
 }
-p, h0, h1, h2, h3, h4, h5, h6, h7, ul, li {
+p, h1, h2, h3, h4, h5, h6, h7, ul, li {
   display                  : block;
   font-family              : verdana, arial, georgia, tahoma, sans-serif, helvetica, times, roman;
   margin-left              : 5%%;
@@ -4605,7 +4605,7 @@ ul, li {
 }
 li { }   /* bullets are rendered as text; the background image was never shipped */
 ul { }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   font-weight              : bold;
   line-height              : 120%%;
   text-align               : left;
@@ -4616,7 +4616,7 @@ h4.norm, h5.norm, h6.norm, h7.norm {
   margin-top               : 10px;
   margin-bottom            : 0px;
 }
-h0 { font-size             : 1.9rem; }
+h1.title { font-size       : 1.9rem; }
 h1 { font-size             : 1.8rem; }
 h2 { font-size             : 1.75rem; }
 h3 { font-size             : 1.7rem; }
@@ -4624,7 +4624,7 @@ h4 { font-size             : 1.65rem; }
 h5 { font-size             : 1.6rem; }
 h6 { font-size             : 1.55rem; }
 h7 { font-size             : 1.5rem; }
-h0, h1, h2, h3, h4, h5, h6, h7 {
+h1, h2, h3, h4, h5, h6, h7 {
   text-shadow              : .2em .2em .3em #999999;
 }
 h1.i { margin-left         : 2em; }
@@ -4641,7 +4641,7 @@ h9.i { margin-left         : 10em; }
   margin-top               : 6px;
   margin-bottom            : 6px;
 }
-h0.toc {
+h1.title.toc {
   margin-left              : 1em;
   font-size                : 1.8rem;
   line-height              : 150%%;