>>170
browser.htmlを編集すればおｋ

<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8" />
<title>Vivaldi</title>
<link rel="stylesheet" href="style/common.css" />
<link rel="stylesheet" href="custom/userCustom.css" />
</head>
<body>
<div id="app" />
<script src="localeSettings-bundle.js"></script>
<script src="vendor-bundle.js"></script>
<script src="common-bundle.js"></script>
<script src="bundle.js"></script>
<script src="custom/userCustom.js"></script>
</body>
</html>

>>176
旧Operaユーザーだったなら楽勝なのにね