My webstore is below and nearly finished:
1) I just want to have an underline for the little brown Header strip at the top.
2) And also Increase the size of the Font of my Business name at the top.
How is this achieved in the code?
I'm Alex, with the Shopify team!
Congratulations on your store, I'm excited to hear that you're getting close to finished! Your theme should have options for changing the font and sizing of the text in your header. To access these controls, head in your admin to Online Store > Themes, and click the Customize button. In the next screen, you'll see a menu to the left - up at the top select the Theme Settings tab, and should see a Typography section there. You can edit your font and text size from here.
If that option doesn't exist, or provide the options that you require for your store, this can be done through altering the code - reaching out to your theme's developer is your best option, in that case. If this is a third-party theme, made by an outside source, then you can reach out to them directly for assistance. If that's a free theme made by Shopify, we'll be glad to help; each of our merchants is entitled to an hour's worth of free design time to help with minor tweaks such as this.
I'll send you out an email once I've posted this response; if this is a Shopify-made theme, I'll be more than glad to pass this along to our Themes team for you, just reply to me there and we'll get to work!
Hope that's helped! Please feel free to let me know, and you can always give us a call or start a live chat at any time. We're open 24/7 for your convenience and always happy to assist.
Alex | Shopify
Sure there is code for Brooklyn theme, have a look at the post