Custom intro text in joomla 3.5 - joomla

Question

I am trying to make the intro text is seperated and isn't extracted from the full text of Joomla 3.5.
To do that: I make a
<div class="intro-custom">the content that i need to show as intro-text</div>
,
put this at the top position of each article and use CSS to hide in display content.
But i dont know how to bring
<div class="intro-custom">
this to the front.
I found this file components/com-contents/view/category/tmpl/default_articles.php
<?php
$text = $article->introtext;
$text = preg_replace('#<div[^>]*class=(["\'])mosimage_caption\\1[^>]*>[^>]* </div>#', '', $text );
$preserv = "";
$text = strip_tags($text, /* exclude */ $preserv );
$text = preg_replace("#<script[^>]*?>.*?</script>#si","",$text);
$text = preg_replace('/{.+?}/','',$text);
$text = preg_replace('/(( )|( ))+/',' ',$text);
$text = preg_replace('/"/',' ',$text);
$text = str_replace(array("\r\n", "\n", "\r"), "", $text);
$text = str_replace("caption","", $text);
$shorttext = substr($text,0,300);
echo '<p>' . $shorttext . '...</p><p>Read more</p>';
?>
I just know CSS and HTML, any help?

Answer 1

Template override
First thing, use template override so that your changes will not be overwritten at next Joomla update. In your case, this means that you need to create a folder:
/templates/[YOUR TEMPLATE]/html/com_content/category/
and copy the file default_articles.php in this folder.
Edit template
If I understood your question correctly, you want to show always the same intro text for all articles, instead of using the intro text from the article themselves.
So you can remove all the code in the file and replace it with:
<div class="intro-custom">
<p>>the content that i need to show as intro-text</p>
<p>Read more</p>
</div>
You can then adapt HTML / CSS as you like.