Fixed Firefox only printing the first page

src/assets/stylesheets/base/_typeset.scss

@@ -58,8 +58,7 @@ kbd {
 .md-typeset {
   font-size: ms(0);
   line-height: 1.6;
-  // Colors should be kept when printing
-  -webkit-print-color-adjust: exact; // stylelint-disable-line
+  color-adjust: exact;
 
   // Default spacing
   p,

src/assets/stylesheets/layout/_base.scss

@@ -80,6 +80,12 @@ body {
       position: fixed;
     }
   }
+
+  // Hack: we must not use flex, or Firefox will only print the first page
+  // see https://mzl.la/39DgR3m
+  @media print {
+    display: block;
+  }
 }
 
 // Horizontal separators
@@ -102,6 +108,12 @@ hr {
   display: flex;
   flex-direction: column;
   flex-grow: 1;
+
+  // Hack: we must not use flex, or Firefox will only print the first page
+  // see https://mzl.la/39DgR3m
+  @media print {
+    display: block;
+  }
 }
 
 // The main content should stretch to maximum height in the table