Index: includes/theme.inc
===================================================================
RCS file: /cvs/drupal/drupal/includes/theme.inc,v
retrieving revision 1.609
diff -u -p -r1.609 theme.inc
--- includes/theme.inc	5 Sep 2010 02:21:37 -0000	1.609
+++ includes/theme.inc	7 Sep 2010 06:50:50 -0000
@@ -143,6 +143,7 @@ function _drupal_theme_initialize($theme
 
   // Grab stylesheets from base theme
   foreach ($base_theme as $base) {
+    // Add stylesheets.
     if (!empty($base->stylesheets)) {
       foreach ($base->stylesheets as $media => $stylesheets) {
         foreach ($stylesheets as $name => $stylesheet) {
@@ -150,8 +151,17 @@ function _drupal_theme_initialize($theme
         }
       }
     }
+    // Remove base stylesheets.
+    if (!empty($base->stylesheets_remove)) {
+      foreach ($final_stylesheets as $media => $stylesheets) {
+        foreach ($stylesheets as $name => $stylesheet) {
+          if (isset($base->stylesheets_remove[$name])) {
+            unset($final_stylesheets[$media][$name]);
+          }
+        }
+      }
+    }
   }
-
   // Add stylesheets used by this theme.
   if (!empty($theme->stylesheets)) {
     foreach ($theme->stylesheets as $media => $stylesheets) {
@@ -160,11 +170,23 @@ function _drupal_theme_initialize($theme
       }
     }
   }
+  // Remove stylesheets specified by this theme.
+  if (!empty($theme->stylesheets_remove)) {
+    foreach ($final_stylesheets as $media => $stylesheets) {
+      foreach ($stylesheets as $name => $stylesheet) {
+        if (isset($theme->stylesheets_remove[$name])) {
+          unset($final_stylesheets[$media][$name]);
+        }
+      }
+    }
+  }
 
   // And now add the stylesheets properly
   foreach ($final_stylesheets as $media => $stylesheets) {
     foreach ($stylesheets as $stylesheet) {
-      drupal_add_css($stylesheet, array('weight' => CSS_THEME, 'media' => $media, 'preprocess' => TRUE));
+      if (file_exists($stylesheet)) {
+        drupal_add_css($stylesheet, array('weight' => CSS_THEME, 'media' => $media, 'preprocess' => TRUE));
+      }
     }
   }
 
@@ -600,7 +622,14 @@ function list_themes($refresh = FALSE) {
     foreach ($themes as $theme) {
       foreach ($theme->info['stylesheets'] as $media => $stylesheets) {
         foreach ($stylesheets as $stylesheet => $path) {
-          $theme->stylesheets[$media][$stylesheet] = $path;
+          if (file_exists($path)) {
+            $theme->stylesheets[$media][$stylesheet] = $path;
+          }
+        }
+      }
+      if (isset($theme->info['stylesheets-remove'])) {
+        foreach ($theme->info['stylesheets-remove'] as $stylesheet) {
+          $theme->stylesheets_remove[$stylesheet] = $stylesheet;
         }
       }
       foreach ($theme->info['scripts'] as $script => $path) {