diff --git a/layout/reftests/css-ruby/reftest.list b/layout/reftests/css-ruby/reftest.list
index a4dab50c6b55..2b3c7db0cf45 100644
--- a/layout/reftests/css-ruby/reftest.list
+++ b/layout/reftests/css-ruby/reftest.list
@@ -23,9 +23,9 @@ test-pref(font.minimum-size.ja,16) == min-font-size-1.html min-font-size-1-ref.h
 load nested-ruby-1.html
 
 # Inter-character ruby is not enabled, and its spec is not considered stable enough.
-pref(layout.css.ruby.intercharacter.enabled,true) fuzzy(0-198,0-70) == ruby-intercharacter-1.htm ruby-intercharacter-1-ref.htm
+pref(layout.css.ruby.intercharacter.enabled,true) fuzzy(0-255,0-148) == ruby-intercharacter-1.htm ruby-intercharacter-1-ref.htm
 pref(layout.css.ruby.intercharacter.enabled,false) != ruby-intercharacter-1.htm ruby-intercharacter-1-ref.htm
-pref(layout.css.ruby.intercharacter.enabled,true) fuzzy(0-92,0-186) == ruby-intercharacter-2.htm ruby-intercharacter-2-ref.htm
+pref(layout.css.ruby.intercharacter.enabled,true) fuzzy(0-255,0-300) == ruby-intercharacter-2.htm ruby-intercharacter-2-ref.htm
 pref(layout.css.ruby.intercharacter.enabled,false) != ruby-intercharacter-2.htm ruby-intercharacter-2-ref.htm
 
 # Testing a specific bug for RTL handling.
diff --git a/layout/reftests/css-ruby/ruby-intercharacter-1-ref.htm b/layout/reftests/css-ruby/ruby-intercharacter-1-ref.htm
index 6327ad90f780..eeb8101a64d2 100644
--- a/layout/reftests/css-ruby/ruby-intercharacter-1-ref.htm
+++ b/layout/reftests/css-ruby/ruby-intercharacter-1-ref.htm
@@ -5,24 +5,25 @@ Reftest 1 for Bug 1395777 (reference file)
 <html lang="zh-TW">
 <head>
 <meta charset="UTF-8">
+<link rel="stylesheet" href="common.css">
 <style>
 body {
-  font-size: 30px;
+  font: 100px Ahem;
   line-height: 1;
 }
 .rbc {
-  height: 30px;
+  height: 100px;
   display: inline-block;
   vertical-align: top;
 }
 .rtc {
-  height: 30px;
+  height: 100px;
   display: inline-block;
   writing-mode: vertical-rl;
   text-orientation: upright;
   vertical-align: top;
   text-align: center;
-  font-size: 30%;
+  font-size: 25%;
 }
 </style>
 </head>
diff --git a/layout/reftests/css-ruby/ruby-intercharacter-1.htm b/layout/reftests/css-ruby/ruby-intercharacter-1.htm
index bb681a286bcb..acc548995884 100644
--- a/layout/reftests/css-ruby/ruby-intercharacter-1.htm
+++ b/layout/reftests/css-ruby/ruby-intercharacter-1.htm
@@ -5,14 +5,16 @@ Reftest 1 for Bug 1395777 (test file)
 <html lang="zh-TW">
 <head>
 <meta charset="UTF-8">
+<link rel="stylesheet" href="common.css">
 <style>
 body {
-  font-size: 30px;
+  font: 100px Ahem;
   line-height: 1;
 }
 rtc {
   writing-mode: vertical-rl;
   text-orientation: upright;
+  font-size: 25%;
 }
 </style>
 </head>
diff --git a/layout/reftests/css-ruby/ruby-intercharacter-2-ref.htm b/layout/reftests/css-ruby/ruby-intercharacter-2-ref.htm
index 90d47ae1d53b..ed8a65ae7d46 100644
--- a/layout/reftests/css-ruby/ruby-intercharacter-2-ref.htm
+++ b/layout/reftests/css-ruby/ruby-intercharacter-2-ref.htm
@@ -5,12 +5,10 @@ Reftest 2 for Bug 1395777 (reference file)
 <html lang="zh-TW">
 <head>
 <meta charset="UTF-8">
+<link rel="stylesheet" href="common.css">
 <style>
 html {
-  font-size: xx-large;
-}
-ruby {
-  width: 1.4em;
+  font: 50px/1 Ahem;
 }
 rtc {
   display: inline-block;
@@ -18,6 +16,9 @@ rtc {
   text-orientation: upright;
   vertical-align: text-top;
 }
+rtc:lang(zh-TW) {
+  font-size: 50%;
+}
 </style>
 </head>
 <body>
diff --git a/layout/reftests/css-ruby/ruby-intercharacter-2.htm b/layout/reftests/css-ruby/ruby-intercharacter-2.htm
index 2819784f166a..0719a0a15968 100644
--- a/layout/reftests/css-ruby/ruby-intercharacter-2.htm
+++ b/layout/reftests/css-ruby/ruby-intercharacter-2.htm
@@ -5,14 +5,18 @@ Reftest 2 for Bug 1395777 (test file)
 <html lang="zh-TW">
 <head>
 <meta charset="UTF-8">
+<link rel="stylesheet" href="common.css">
 <style>
 html {
-  font-size: xx-large;
+  font: 50px/1 Ahem;
 }
 rtc {
   writing-mode: vertical-rl;
   text-orientation: upright;
 }
+rtc:lang(zh-TW) {
+  font-size: 50%;
+}
 </style>
 </head>
 <body>
