diff --git a/resources/com/google/gitiles/templates/Common.soy b/resources/com/google/gitiles/templates/Common.soy
index c5fb238..6df4e43 100644
--- a/resources/com/google/gitiles/templates/Common.soy
+++ b/resources/com/google/gitiles/templates/Common.soy
@@ -24,7 +24,7 @@
       */
   {@param? customVariant: ?}  /** variant name for custom styling. */
   {@param breadcrumbs: ?}  /** navigation breadcrumbs for this page. */
-  {@param? css: list<?>}  /** optional list of CSS URLs to include. */
+  {@param? css: list<?>|null}  /** optional list of CSS URLs to include. */
   {@param? containerClass: ?}  /** optional class to append to the main container. */
   {@inject staticUrls: ?}
   {@inject SITE_TITLE: string}
@@ -44,7 +44,7 @@
   </title>
 
   <link rel="stylesheet" type="text/css" href="{$staticUrls.BASE_CSS_URL}">
-  {if $css and length($css)}
+  {if $css && length($css)}
     {for $url in $css}
       <link rel="stylesheet" type="text/css" href="{$url}">
     {/for}
@@ -57,7 +57,7 @@
     <div class="Header">
       {call customHeader variant="'' + ($customVariant ?? '')" /}
 
-      {if $menuEntries and length($menuEntries)}
+      {if $menuEntries && length($menuEntries)}
         <div class="Header-menu">
         {for $entry in $menuEntries}
           {sp}
@@ -75,7 +75,7 @@
 
   <div class="Site-content">
     <div class="Container {if $containerClass}{$containerClass}{/if}">
-      {if $breadcrumbs and length($breadcrumbs)}
+      {if $breadcrumbs && length($breadcrumbs)}
         <div class="Breadcrumbs">
           {for $entry, $index in $breadcrumbs}
             {if $index > 0}{sp}/{sp}{/if}
diff --git a/resources/com/google/gitiles/templates/ObjectDetail.soy b/resources/com/google/gitiles/templates/ObjectDetail.soy
index 5e5a3a8..1dd3a40 100644
--- a/resources/com/google/gitiles/templates/ObjectDetail.soy
+++ b/resources/com/google/gitiles/templates/ObjectDetail.soy
@@ -105,7 +105,7 @@
   </div>
 {/if}
 
-{if $diffTree and length($diffTree)}
+{if $diffTree && length($diffTree)}
   <ul class="DiffTree">
     {for $entry in $diffTree}
       <li>
@@ -333,7 +333,7 @@
     </tr>
   </table>
 </div>
-{if $message and length($message)}
+{if $message && length($message)}
   {call message_}
     {param className: 'u-pre u-monospace MetadataMessage' /}
     {param message: $message /}
diff --git a/resources/com/google/gitiles/templates/PathDetail.soy b/resources/com/google/gitiles/templates/PathDetail.soy
index 3b5c9be..4c0ddd7 100644
--- a/resources/com/google/gitiles/templates/PathDetail.soy
+++ b/resources/com/google/gitiles/templates/PathDetail.soy
@@ -30,7 +30,7 @@
   {@param data: ?}  /** path data, matching the params for one of .treeDetail, .blobDetail,
       .symlinkDetail, or .gitlinkDetail as appropriate. */
   {@inject staticUrls: ?}
-{if $type == 'REGULAR_FILE' or $type == 'EXECUTABLE_FILE'}
+{if $type == 'REGULAR_FILE' || $type == 'EXECUTABLE_FILE'}
   {call common.header data="all"}
     {param css: [$staticUrls.PRETTIFY_CSS_URL] /}
   {/call}
diff --git a/resources/com/google/gitiles/templates/RepositoryIndex.soy b/resources/com/google/gitiles/templates/RepositoryIndex.soy
index e8ec346..f069055 100644
--- a/resources/com/google/gitiles/templates/RepositoryIndex.soy
+++ b/resources/com/google/gitiles/templates/RepositoryIndex.soy
@@ -71,7 +71,7 @@
          readonly="readonly" value="git clone {$cloneUrl}">
 </div>
 
-{if $hasLog and (length($branches) or length($tags))}
+{if $hasLog && (length($branches) || length($tags))}
   <div class="RepoShortlog">
     <div class="RepoShortlog-refs">
       {call branches_ data="all" /}
@@ -87,7 +87,7 @@
 
 {elseif $hasLog}
   {call common.streamingPlaceholder /}
-{elseif length($branches) or length($tags)}
+{elseif length($branches) || length($tags)}
   {call branches_ data="all" /}
   {call tags_ data="all" /}
 {else}