Really sorry for your loss.
If the dress code is black then stick with plain. You may be hanging around outside the crematorium or the church so think about a coat or jacket so that you don't go blue with cold. A bright scarf that you could throw on if you want or need it could relieve the all black look if needed. These days funeral dress code is a nightmare. I'm a fan of all black as it is simple but I've done funerals where the family have colour coordinated ties and scarves with the deceased's favourite colour and that looks good as well.
Look after yourself post funeral. There can be a big dip post service which catches even the most prepared out.