Resize forum to "90%" etc.

[ɔɔɔɔɔɔuɥoɾ]

Just find the "br_wrap" style in css/index.css and remove the "width: 1240px". It will then be just full screen width.

No need to add more markup.

Depends on what the OP wants really, I believe adding the function of the customizable width is best (if its possible with the themes coding), this way it can be changed easily to suit any future changes, but if one just wants it to work, then their are several options

[busterone]

All smf 2 versions of Black Rain have the width set in css

Code Select Expand

/* this is the main container surrounding everything, use this to set forum width, font-size  etc. */
#mainframe
{
font-size: 85%;
width: 95%;
margin: auto;
}

[Mikirin]

I'm sorry.... I have about 0 experience with coding... The best I've had was proboards.
There's stuff like "begining with Line 1" and such... Where am I supposed to be here?

[busterone]

./themes/blackrain/css/index.css
Depending on which version of Black Rain you are using, the above directory may be blackrain2, blackrain20, or blackrain2_20

[Mikirin]

i have the first version.
I'm sorry I'm dumb at this.
Also, as soon as I posted the link here, I got some spam ads. >.<

[Mikirin]

Just find the "br_wrap" style in css/index.css and remove the "width: 1240px". It will then be just full screen width.

No need to add more markup.

This worked! thank you soso much!

[bloc]

Just find the "br_wrap" style in css/index.css and remove the "width: 1240px". It will then be just full screen width.

No need to add more markup.

This worked! thank you soso much!

yw. Glad it helped.

[busterone]

Glad it worked. 
Odd, my copies of Black Rain do not have  "br_wrap" in css.