Is this really blackout 100%?

Yes, these curtains are 100% blackout curtains, block out sunlight completely.

How many pieces in a package？ Is each panel 52 in width?

Yes, 2PCS in a package, each panel is 52" width,total 104" width.

Why is the color of the curtains I received a little different from when I browsed?

Hi, there is a slight difference in the color of the curtains due to different display devices or lighting problems.

How can I remove wrinkles from these curtains?

A quick steaming iron on the back side can effectively smooth out any wrinkles. Or the wrinkles will disappear after hanging few days.