Is CSS injection possible on iPad using Safari?
To inject a custom CSS into a webpage on iPad you can use the app Shortcuts. First, you need to create a new shortcut:


Open Shortcuts
Select Create Shortcut > Web > Run JavaScript on Web Page
Use the following JavaScript:


function addStyleString(str) {
    var node = document.createElement('style');
    node.innerHTML = str;
    document.body.appendChild(node);
}

addStyleString('body { color: red !important }');
addStyleString('body { background: silver !important }');
// This way allows you to add CSS in multiple passes


// Call completion to finish
completion();



Tap Next
Add the Shortcut Name


To apply a custom CSS you need to run the shortcut in Safari:


Open a web page in Safari
Tap on the share button
Scroll all the way down and tap on the newly created shortcut.


HINT: Use !important in CSS injections to override default rules.