Mensaje de error

Notice: Undefined index: HTTP_REFERER in eval() (line 45 of modules/php/php.module(81) : eval()'d code).
eval() (Line: 81)
php_eval('@media (min-width:320px)  { 
 #consultabd {
  width: 980%; 
 }
}
@media (min-width:480px)  { 
 #consultabd {
 width: 400px;
 }
}
@media (min-width:600px)  { 
 #consultabd {
width: 550px;
 }
}
@media (min-width:801px)  { 
 #consultabd {
    width: 720px;
 }
}
@media (min-width:900px) { 
 #consultabd {
 width: 850px;
 }
}
@media (min-width:1025px) { 
 #consultabd {
    width: 1000px;
 }
}
@media (min-width:1281px) { 
 #consultabd {
   width: 1200px;
 }
}

<?php
$url = "";
if(isset($_SERVER['HTTP_REFERER']))
{
$url = "?url=".$_SERVER['HTTP_REFERER'];
$url = "";
}
?>
Origen: <?php echo $_SERVER['HTTP_REFERER']; ?>
">
<?php
unset($url);
?>
') (Line: 26)
Drupal\php\Plugin\Filter\Php->process('@media (min-width:320px)  { 
 #consultabd {
  width: 980%; 
 }
}
@media (min-width:480px)  { 
 #consultabd {
 width: 400px;
 }
}
@media (min-width:600px)  { 
 #consultabd {
width: 550px;
 }
}
@media (min-width:801px)  { 
 #consultabd {
    width: 720px;
 }
}
@media (min-width:900px) { 
 #consultabd {
 width: 850px;
 }
}
@media (min-width:1025px) { 
 #consultabd {
    width: 1000px;
 }
}
@media (min-width:1281px) { 
 #consultabd {
   width: 1200px;
 }
}

<?php
$url = "";
if(isset($_SERVER['HTTP_REFERER']))
{
$url = "?url=".$_SERVER['HTTP_REFERER'];
$url = "";
}
?>
Origen: <?php echo $_SERVER['HTTP_REFERER']; ?>
">
<?php
unset($url);
?>
', 'es') (Line: 118)
Drupal\filter\Element\ProcessedText::preRenderText(Array)
call_user_func(Array, Array) (Line: 378)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 87)
__TwigTemplate_2e04604d40adfffe9696b81b9ebd4d3153930632843ca30993944ac2578305e6->doDisplay(Array, Array) (Line: 432)
Twig_Template->displayWithErrorHandling(Array, Array) (Line: 403)
Twig_Template->display(Array) (Line: 411)
Twig_Template->render(Array) (Line: 64)
twig_render_template('themes/librarian/templates/field.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('field', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array) (Line: 450)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array) (Line: 490)
Drupal\Core\Template\TwigExtension->escapeFilter(Object, Array, 'html', NULL, 1) (Line: 104)
__TwigTemplate_a44d8d14136bdb92ed90efcdff71144baac9e8b0ec5ac2b33d5a5a56babb265f->doDisplay(Array, Array) (Line: 432)
Twig_Template->displayWithErrorHandling(Array, Array) (Line: 403)
Twig_Template->display(Array) (Line: 411)
Twig_Template->render(Array) (Line: 64)
twig_render_template('themes/librarian/templates/node--page.html.twig', Array) (Line: 384)
Drupal\Core\Theme\ThemeManager->render('node', Array) (Line: 437)
Drupal\Core\Render\Renderer->doRender(Array, ) (Line: 195)
Drupal\Core\Render\Renderer->render(Array, ) (Line: 226)
Drupal\Core\Render\MainContent\HtmlRenderer->Drupal\Core\Render\MainContent\{closure}() (Line: 582)
Drupal\Core\Render\Renderer->executeInRenderContext(Object, Object) (Line: 227)
Drupal\Core\Render\MainContent\HtmlRenderer->prepare(Array, Object, Object) (Line: 117)
Drupal\Core\Render\MainContent\HtmlRenderer->renderResponse(Array, Object, Object) (Line: 90)
Drupal\Core\EventSubscriber\MainContentViewSubscriber->onViewRenderArray(Object, 'kernel.view', Object)
call_user_func(Array, Object, 'kernel.view', Object) (Line: 111)
Drupal\Component\EventDispatcher\ContainerAwareEventDispatcher->dispatch('kernel.view', Object) (Line: 156)
Symfony\Component\HttpKernel\HttpKernel->handleRaw(Object, 1) (Line: 68)
Symfony\Component\HttpKernel\HttpKernel->handle(Object, 1, 1) (Line: 57)
Drupal\Core\StackMiddleware\Session->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\KernelPreHandle->handle(Object, 1, 1) (Line: 184)
Drupal\page_cache\StackMiddleware\PageCache->fetch(Object, 1, 1) (Line: 121)
Drupal\page_cache\StackMiddleware\PageCache->lookup(Object, 1, 1) (Line: 75)
Drupal\page_cache\StackMiddleware\PageCache->handle(Object, 1, 1) (Line: 47)
Drupal\Core\StackMiddleware\ReverseProxyMiddleware->handle(Object, 1, 1) (Line: 52)
Drupal\Core\StackMiddleware\NegotiationMiddleware->handle(Object, 1, 1) (Line: 23)
Stack\StackedHttpKernel->handle(Object, 1, 1) (Line: 690)
Drupal\Core\DrupalKernel->handle(Object) (Line: 19)

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