diff --git a/NEWS.mdtext b/NEWS.mdtext
index 72ea380..58cabd5 100644
--- a/NEWS.mdtext
+++ b/NEWS.mdtext
@@ -1,5 +1,10 @@
 # InDefero 1.2.1 - XXX XXX XX XX:XX:XX UTC 201X
 
+## Bugfixes
+
+- The diff view now renders properly in Firefox when a minimum font size
+  is configured or the user zooms the web page (fixes issue 773)
+
 ## Language and Translations
 
 - Multiple fixes to English source strings (fixes issues 763, 766, and 772,
diff --git a/src/IDF/Diff.php b/src/IDF/Diff.php
index 6c76ce2..ac86934 100644
--- a/src/IDF/Diff.php
+++ b/src/IDF/Diff.php
@@ -184,12 +184,12 @@ class IDF_Diff
             $added = $added[0] + $added[1];
             $leftwidth = 0;
             if ($added > 0)
-                $leftwidth = ((ceil(log10($added)) + 1) * 8) + 12;
+                $leftwidth = ((ceil(log10($added)) + 1) * 8) + 17;
 
             $removed = $removed[0] + $removed[1];
             $rightwidth = 0;
             if ($removed > 0)
-                $rightwidth = ((ceil(log10($removed)) + 1) * 8) + 12;
+                $rightwidth = ((ceil(log10($removed)) + 1) * 8) + 17;
 
             // we need to correct the width of a single column a little
             // to take less space and to hide the empty one
@@ -411,11 +411,11 @@ class IDF_Diff
 
         $leftwidth = 1;
         if ($max_lineno_left > 0)
-            $leftwidth = ((ceil(log10($max_lineno_left)) + 1) * 8) + 12;
+            $leftwidth = ((ceil(log10($max_lineno_left)) + 1) * 8) + 17;
 
         $rightwidth = 1;
         if ($max_lineno_right > 0)
-            $rightwidth = ((ceil(log10($max_lineno_right)) + 1) * 8) + 12;
+            $rightwidth = ((ceil(log10($max_lineno_right)) + 1) * 8) + 17;
 
         $inner_linecounts_left =
           '<table class="diff-linecounts">' ."\n".
diff --git a/www/media/idf/css/style.css b/www/media/idf/css/style.css
index 481c3d9..8e12ddc 100644
--- a/www/media/idf/css/style.css
+++ b/www/media/idf/css/style.css
@@ -652,7 +652,7 @@ table.diff-contents {
 
 table.diff-linecounts tr,
 table.diff-contents tr {
-  height: 18px;
+  height: 22px;
 }
 
 table.diff-linecounts tr {
@@ -664,8 +664,9 @@ table.diff-linecounts tr:first-child {
 }
 
 table.diff-linecounts td {
+  line-height: 12px;
   font-size: 90%;
-  padding: 1px 10px;
+  padding: 2px 10px;
   text-align: right;
   border-left: 1px solid #d3d7cf;
 }