Where to enter the code: Go to your profile. In the top right corner, click "edit my profile layout." A blue box now appears in the bottom right. Click "Theme." A new box appears over your screen. Click the last tab, "CSS." The box that appears is where you enter the code.
And now, the code:
In the CSS box, to make every box transparent, copy/paste the code below:
.panel {background: transparent;}
To make all of the headers of those boxes transparent as well, you can also add:
.panel h2 {background: transparent;}
To remove the title from each box, click on "edit" in the top right of each box and delete the words (or make a new one). Also, you can delete some of the boxes to get them out of your way. If there are any that you don't want, click the little x in the top right corner. You can always return it by clicking "Content" on the blue box and selecting the panel you want. You can also rearrange the boxes. Click and drag. If you want some panels to remain opaque, the codes above won't work. You'll have to write individual codes for each box that you want to make transparent.
Be sure to hit "Save" in the blue box or you lose all your work.
Oh yeah! Here's another code to consider. As it is now, your background image will scroll up and down along with the boxes (like one layer). You can make the background image remain stationary while the boxes scroll above it (like the boxes are a second layer above the background image). Add this code: