Beh sinceramente la ho letta e la sto rileggendo, non avrei scritto se avessi trovato la soluzione.
Pag. 3 di “Hypertext marks in LaTeX: a manual for hyperref”
Other options control the appearance of links, and give extra control over PDF output. For example, colorlinks, as its name well implies, colors the links instead of using boxes; this is the option used in this document.
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colorlinks (boolean). Colors the text of links and anchors. The colors chosen depend on the the type of link. At present the only types of link distinguished are citations, page references, URLs, local file references, and other links.
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citebordercolor RGB color 0 1 0 The color of the box around citations
filebordercolor RGB color 0 .5 .5 The color of the box around links to files
linkbordercolor RGB color 1 0 0 The color of the box around normal links
menubordercolor RGB color 1 0 0 The color of the box around Acrobat menu links
pagebordercolor RGB color 1 1 0 The color of the box around links to pages
urlbordercolor RGB color 0 1 1 The color of the box around links to URLs