Step 1
Create a simple 400px by 400 px square, with 15 px corner radius.
Step 2
Create an angled linear gradient on the square, where both color stops are 50% opaque. Choose a near-white at the bottom and light gray at the top..
Step 3
Add a few randomly-sized rectangles that go off the bounds. and blur them at random amounts (between 20-30px in this case). These will create the light streaks..
