Safest long term dye for teenager?

[MandyBeth]

My older daughter has had major color change as her health has improved. She's now got about 8 inches of a darker golden brown color, but the rest ranges from a very pale blonde to a mid gold blonde. She doesn't like the demarcation, nor do I blame her.

But I'm not sure how best to get her hair to an allover even color - or more correctly, how to request that. Plus, what is safest that will last?

Thanks!

[lapushka]

I'd dye the lighter color to match the darker color, this way you can use a semi-permanent in the same shade as the outgrowth - safest and easiest way to do this.