There is a super quick fix for this. Here's how:
1. Download the PDF from Safari Portal by clicking Save and then Save with PDF.
2. Open the file in Preview on your computer, and click Print.
3. Show the Details and scale it to 90% (you can play with the exact percentage you want later), then click Save as PDF.
💥 Bam! Margins! If you need more you can scale it a bit more; it doesn’t affect the quality of the text and it’s still perfectly legible.