hotfix pagebreak

static/js/pdf-export.js

@@ -530,12 +530,26 @@ function printStyles(cssSize, pageWidthMm, pageHeightMm, marginMm, preserveColor
     }
 
     .pdf-content .pdf-keep-unit {
+      /*
+       * Chromium can leave a 1-2 px fragment of an avoided block on the
+       * previous page before moving the real block to the next page.
+       * Making the keep unit an atomic inline-block prevents that ghost
+       * fragment while preserving book-like pagination.
+       */
+      display: inline-block;
+      width: 100%;
+      vertical-align: top;
+      box-sizing: border-box;
       break-inside: avoid-page;
       page-break-inside: avoid;
     }
     .pdf-content .pdf-keep-unit > :first-child { margin-top: 0 !important; }
     .pdf-content .pdf-keep-unit > :last-child { margin-bottom: 0 !important; }
     .pdf-content .pdf-atomic-visual {
+      display: inline-block;
+      width: 100%;
+      vertical-align: top;
+      box-sizing: border-box;
       break-before: avoid-page;
       page-break-before: avoid;
     }