Each internal link has an id string equal to the passage it links to. You can make a stylesheet passage and target each link by passage name.
For Example a passage with the title "My Awesome Passage"
Should have the css id selector
However the insertElement function is missing a step required to eliminate spaces from element ids. So passages with spaces in the titles would not have targetable id selectors.
Heres a fix. Create a passage tagged "script" and add the code below.
window.oldInsertElement = window.insertElement;
window.insertElement = function(a,d,f,c,e){
var b = window.oldInsertElement.apply(this, arguments);
b.id = b.id.replace(/ /g,"");
return b
};
This will eliminate spaces in ids generated by twine.