White and another color, plus some black (or another color from the chair, like the fuchsia and the paler pink; .

What did she like about the chair? The color, pattern, shape?

She could also have a colorful accent wall and put the white bed in front of it.

http://www.chipchick.com/2011-09-ikea-share-space.php

That chair is wonderful, but I can see that it's busy print could make choosing bedding frustrating. What I would do is find a black and white print bedskirt that your daughter likes. There are many I found over on Wayfair.com. Then I would pair it with a solid hot pink , or green or other color that is in the chair and that your daughter likes. My first thought is a matelassé, because they wash so easily. My last choice would be a comforter cover. DD has one on her bed here at home and hates that the comforter inside it always slips down. Hopefully, add pillow shams to match the bedskirt and some fun throw pillows that she likes. Perhaps ones with sayings, and/or bright colors that coordinate with her chair. Here are a few of Wayfair's bedskirts:

Something like this?

If you get Ikea duvet covers and duvets, they don't slide around. They have lots of cute white covers that are inexpensive.

My first thought was a white comforter as well. it's a small room, so you don't want too many patterns or colors vying for attention since the show stopper is that chair!

I would get a few throw pillows and sheets in any one of the colors, pink, yellow, orange if you do the white cover.

I like the pink comforter that Lynn posted too.

Although I love white and/or cream, and actually have had a comforter that color for many years, unless your daughter is a super clean teen, which mine wasn't . . . or any other teen I've ever known . . . I'd steer clear of a white bedspread. Teens love to sprawl on their beds, and so do their friends. A bit of dirt on their jeans, their socks, their shoes, their shorts, their dog or cat, and you're washing that comforter twice a week.

I think the solid pink bedding shown by Lynn and celerygirl would look much better with the colorful chair. Aside from any issues of keeping the bedding clean looking, white would look like it was missing color in this case. Also I think adding the black animal print bedskirt grounds the bed and makes it relate even better to the chair (which btw I LOVE that pattern.) You are so lucky to get to work on a teen girl's room. I have boys. They don't care one bit what I do with their rooms decor wise.

My DD has had white duvet covers for ages. You throw it into the washing machine with your regular sheets, wash at hot, and if necessary bleach. And because it's about 29.99, you have a bunch and throw them out after a few years.

But I'd go with a plain white duvet. Love this one (Alvine)

actually i love simple plain sheets, you get other colors and patterns you often can not match later. how about a simple jeans throw over it. that will keep it simple and easy to clean.

18" for $47 and other colors.

Safavieh Amy Mini Table Lamp, Pink · More Info

Is her flooring light, medium, or dark?

PInk is girly, and the green is neither... what if accent wall painted lilac?

Safavieh Amy Mini Table Lamp, Green · More Info

Pick 1 or 2 colors from her chair?

“I like to layer patterns, and there’s not necessarily a wrong way to do it,” Weaver says. She pulled out a range of large and small-scale patterns in pinks and oranges from their quilts. White Dove, Benjamin Moore; ceiling paint: Razzle Dazzle, Benjamin Moore.[

Alicia Weaver Design, LLC

“The girls love hot pink, but it’s way too strong a color for all four walls,” Weaver says. Instead, she painted the fifth wall, the ceiling, in the hot hue. She pulled it down the top of the walls to meet the existing moldings. “The ceilings are quite high; this helped to bring them down and make the room more cozy,” she explains.

$40 bed in bag. Solid side.... has fun sheets to add 1 other pattern.

Butterfly Dots Ultra Soft Microfiber Twin Comforter Set · More Info

Beige carpeting? - what about another soft contrast to white bed, and for example, soft yellow paint / from art. Blue lamps, etc....

"Australia, Sunshine and Surf Poster Australia 1936" Print, 24"x36" · More Info

Something soft and feminine for her / or more sporty and fun?? Orange for instance isn't so feminine....??

Which are her favorite colors in the chair - red, orange, pink, blue, green, yellow?

Neutral grey bedding with her white bed - maybe she'd find striking lamps and a piece of art.....

what is wall color currently?

https://www.groupon.com/deals/gg-reversible-chevron-pattern-quilt-sets

Understood: hard for her to make a decision. Here's a room with bit of repeating with teardrops on wall, and on pillow. She could place - and not too large a project - stick-on decals onto the wall....

Rooms to Inspire by the Sea by Annie Kelly beach homes houses · More Info

Confetti Triangles Circle Wall Decal, 20" Diameter · More Info

Personally, I liked idea of black - instead, here's repeating chrome-grey [of chair] in triangles. $30. Lots of colors too. Thinking she could form flower petals with them, maybe over her headboard, rounded like flowers.

Triangle Fabric Wall Decals, Set of 32, Grey · More Info

I'm assuming that no 14-year old, especially one who picks that Ikea chair, would allow pink butterflies on her sheets.

What was it that appealed to her about the chair, i.e. shape, colors, pattern? Does she still like it, or is she over it?

You could also exchange for a different cover.

If one window - and neutrals mostly around - could be place for color from chair.

nosoccer - mine was for the solid side... if it was my post. Hot pink good with white.

I like the ideas so far. I might choose a color from the chair for an accent wall. Then leave the rest of the walls white. The dresser below is from IKEA. You could easily add colorful knobs.

Just an FYI: I just got the latest Linen Source catalog and they are going out of business! They have tons of their comforters, bedspreads and sheets and everything else at a really good sale price with free shipping if you spend $75 or more through July 30th. I saw some really cute matelasse coverlets in pink for a good price, plus a lot of other things too.

Sorry for your loss.

take your time op, sorry for the loss.