The only code that is needed to remove indention from list elements is
ul {
list-style:none;
/* list-style-position:outside; /* is the default */
padding-left:0;
outline:1px solid blue; /* TEST Outline */
}
working page:
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width,initial-scale=1.0">
<link rel="stylesheet" href="css/stylesheet.css">
<title>list tester</title>
<!--
https://www.sitepoint.com/community/t/css-ios-browser-indenting-list/318602
-->
<style>
ul {
list-style:none;
/* list-style-position:outside; /* is the default */
padding-left:0;
outline:1px solid blue; /* TEST Outline */
}
</style>
</head>
<body>
<ul>
<li>Must be a NEW build from a balsa kit or plans.</li>
<li>Previously started kits are okay.</li>
<li>Models must be radio-controlled.</li>
<li>To enter, you must post at least one current photo.</li>
<li>To finish the challenge, your plane must be flown.</li>
<li>The Challenge is open to any AMA member.</li>
</ul>
</body>
</html>
First, test my demo page alone and unchanged in the iOS device. If it works properly, the trouble is elsewhere in your code. If mine does not work OR for more help, please post a working page (similar to mine) showing all of your relevent code.