Extending the width of my header

I currently have the Tesseract theme which is not on wordpress. I’ve been able to tweak just about anything except the header.. I need my logo to be in the header. It always comes out chopped or extremely small. I have tried the header section and logo section, nothing close to how Id like it. So currently I’ve been using the Ubermenu which gives me an option to add custom content. Even that does not look right. I’ve checked the style sheet, etc in header width.. it’s at 100%. Any ideas? Oh and yes I have a child them. Thank you!