fix printing

IPython/html/static/base/less/page.less

@@ -14,7 +14,9 b' body {'
     right: 0px;
     top: 0px;
     bottom: 0px;
+    @media not print {
     .vbox();
+    }
     overflow: visible;
 }
 
@@ -82,10 +84,12 b' body {'
     width: 100%;
     display: none;
     .border-box-sizing();
-    flex: 1;
     overflow: auto;
+    @media not print {
+      flex: 1;
     height: 0px; // triggers overflow, but overridded by flex
 }
+}
 
 /* Smaller buttons */
 .ui-button .ui-button-text {

IPython/html/static/style/style.min.css

@@ -8265,6 +8265,10 b' body {'
   right: 0px;
   top: 0px;
   bottom: 0px;
+  overflow: visible;
+}
+@media not print {
+  body {
     /* Old browsers */
     display: -webkit-box;
     -webkit-box-orient: vertical;
@@ -8279,7 +8283,7 b' body {'
     display: flex;
     flex-direction: column;
     align-items: stretch;
-  overflow: visible;
+  }
 }
 #header {
   /* Initially hidden to prevent FLOUC */
@@ -8343,10 +8347,14 b' body {'
   box-sizing: border-box;
   -moz-box-sizing: border-box;
   -webkit-box-sizing: border-box;
-  flex: 1;
   overflow: auto;
+}
+@media not print {
+  #site {
+    flex: 1;
     height: 0px;
   }
+}
 /* Smaller buttons */
 .ui-button .ui-button-text {
   padding: 0.2em 0.8em;