You don’t need to repaint your house. Get your daughter a long white cane. You can get one for free from NFB. It will keep her from falling down stairs and running into walls. As she get more comfortable she’ll learn your house and won’t need to use the cane at home anymore. The cane is something she can control and it can be used in any environment no matter the color scheme. It will give her autonomy over her surroundings and grow her confidence in her own abilities. There’s a really good group on Facebook for parents of blind children where you can get more ideas from other families search NOPBC and it should come up. I can send you a direct link too.

I second the cane. She probably won't need it in the house for long, but then she might. Depends on her. Becoming blind takes getting used to, whether you go total or lose it gradually. If she's trained properly how to use the cane, she'll figure herself out in time. What she needs most from you is support, and not to be treated differently because of her vision. It's hard for the visual to fathom what it's like to not have vision She will have challenges, but being blind is, in many ways far less of a problem in today's society than it once was. Especially if she has even a little vision left. But even if she doesn't, with enough confidence, training and support, she will be fine.

Not sure how it would work with smaller children but hand rails. i feel i can do any stairs if i have a hand rail, or a heavy duty tape to mark the edge of each step might work. i use tape on the stone steps in the garden.

I was told to use high-contrast tape around my house, as well as adhesive dots on certain buttons, etc. I purchased both on Amazon only because the support office I was going through was out of supplies.

How old is your step daughter? Also, what country do you live in? Age and location matter for what services you get and what are appropriate accommodations.
If your step daughter is just a toddler, it may be appropriate to be giving her a cane to use in the house now in order to increase her exposure to it and learn how it functions.
If your step daughter is older, it isn't very common to use a cane within your own home as it should always be familiar and safe. If you have a lot of people in your home though and things are always getting left on the floor or moved about, your step daughter may benefit from using a cane at home.
Changing the paint is an option either way. If you were thinking about panting to begin with, contrasting colors may help your step daughter, but what is she going to do the next time she is in a challenging environment like a dark movie theater or restaurant?
The moral of the story is that your step daughter needs to learn the skills she needs to keep herself safe in all environments. If she is slipping up and down the stairs at home, she is at risk of doing the same thing or worse in any environment she encounters with stairs. Is your step daughter working with a orientation and mobility specialist at school? If she isn't three yet, do you have one coming to your home? Make sure that they know about these slips. It may change what they are teaching her so that she can feel safe and confident everywhere she goes.
My opinion is, don't change the environment unless you were planning to anyway. Change the skills your step daughter is learning so that she can tackle any environment like this on her own with confidence.

I hold onto the railing and if I’m going down, I tap my front of my foot on the edge of the stairs, and when I’m going up I tap my foot where the next step is. For walking around the house I tend to trail my hand against the walls. I can’t promise that this will be effective for your step-daughter though, but I wish you luck :) Also maybe look into O&M or occupational therapy for around the house?

I’m partially sighted and can navigate well without a cane, but I have been using one especially to help me detect changes in height, like stairs and curbs. I’ve noticed I can navigate stairs that have a defined edge (Like the edge is colored black or has a distinct texturing). She should receive orientation and mobility training.

Most stairs are 7 inches on the riser and 11 on the tread so knowing that, if your house is the same, she can just learn what that feels like. I run up and down stairs all over the place.

What you could do which my parents did at least for nights was to get glow in the dark electric tape at the edge of the stairs.

Otherwise maybe a metal stair edge.

Ideally you'd want specialist advice rather than general advice on contrasting colors for door frames before spending money and possibly making mistakes.

Given you've put new carpet down on the stairs, it seems you've lived in the house for a while and your step child knows his/her way around, so I'd disregard any suggestion involving using a cane inside.

Kids want to move about quickly, they obviously need to do this. And they are going to bump and fall.

The doorframe idea is great.

Don't attach anything to the stairs unless advised to do so by a pro, it might be a hazard. As another member commented, put hivis tape on the stairs for now, until you can get your home assessed properly.

Extra lighting around the stairs might help and tape around the doorframe could be a quick fix too.

It's hard not to make assumptions when replying to a post, but my experience of this issue is to get a proper assessment done before making changes to your home.

Basically, don't be like me and do it half assed and/or not allow for further vision loss.

Cheers