Header (Portobello)
Learn how to configure the theme header here. In your control panel, go to Storefront > Themes, and click the blue "Customize" button to launch Theme Editor. In the left hand column of the Theme Editor, click the panel labelled 'Header'
Header Features
Cart Icon
You can change the icon used in the utility navigation between a bag, cart and basket icon.
Show Wishlists Link in Header
Enable this option to have the wishlist icon display in the header, between the Search and Account icons, when a customer adds a product to a wishlist.
Image Based Logo
Image Logo Size
You can adjust the size of the logo here.
Please note before you consider adjusting the recommended sizes, take a look at how three of the biggest brands on the planet size their logos.
Text Based Logo
Configure the size and color of your text based logo here.
Main Navigation
Sticky Navigation
Enabling this feature allows the main navigation bar to stick to the top of the viewport on large screens and above. This simplifies the layout of the utility navigation, only displaying search, cart and compare when available. 
While the sticky navigation is configured to work with unlimited categories, for the best appearance limit your main navigation items to 8 or less.
Hide Logo on Sticky Navigation
Checking this will hide the logo when the sticky navigation activates on scroll. Scrolling back to the top of the page will make the logo reappear.
Hide Web Pages in Main Navigation
Checking this option stops information pages created in the Content Management System (CMS) from appearing in the top navigation bar.
Hide "View Parent" Links
By default with the style of dropdown navigation we use, lists appear when the top level item is clicked. In this case, we present a "View Parent" link to allow visitors to access the top level category. This option prevents the "View Parent" link appearing.
Show "Brands" in Navigation
This adds an additional "Brands" link to the navigation. This is just a top level link that redirects to the main Brands page, it does not create a drop down list.
Enclosed Navigation
Setting Up Menu Depths for dropdown menus to appear, you need to set up a menu display depth of at least 2 levels deep.
To set this, in your store Control Panel, go to Store Setup > Store Settings and click the Display tab. Under the Category Setting heading, look for the Menu Display Depth field.
Check this option to hide all top level categories inside a "Shop Online" link. Clicking the link will make a navigation list appear.
You can rename the link that appears in the menu with the Enclosed Category Menu Item Name text box in this section. Note that the text field has a 64 character limit