Your Aarcade theme settings, styling and CSS have no effect upon the appearance of your Seamless Checkout.
The only tools available to edit the appearance of your Seamless Checkout are the colour and font pickers in the Customize design > Customize area of your Big Cartel admin area - see How do I use the Big Cartel "Customize design" area with my Aarcade theme?
If you have Seamless Checkout enabled, use these colour and font pickers to edit and save colour and font values that closely match your theme’s appearance. Test this by checking out through your shop in the public space.
How the Seamless Checkout works
The layout and functionality of the Seamless Checkout is completely controlled by Big Cartel. It is not part of your theme or shop. It is a separate checkout processor, the same way that the original off-site PayPal checkout page is. The difference is that this new checkout processor is provided by Big Cartel to make the checkout experience more seamless and efficient for your customers.
For this reason, other than changing colours and fonts (see previous section), there is no way to influence the way the Seamless Checkout system appears or behaves.
Oversized header/logo image
To correct an oversized header/logo image, refer to section Seamless checkout header/logo image of the support article How do I upload and style my own logo or header image for my Big Cartel theme?
Capturing customer data at the Seamless Checkout
Big Cartel’s seamless checkout does provide a Notes or instructions (optional) for your customer to enter data prior to completing their order. Unfortunately there is no way to carry data over from the theme space to pre-populate this field and there is no way to edit or highlight the labelling of this field.
If you have critical data that you must collect from your customer, the best available option is to post a notice on the cart page that reminds the customer to enter the data in the Notes or instructions (optional) field during checkout.
So, for example, we might add an
x-ic-after-cart-items page to insert the notice into our cart - see Insert Content - Cart Page - with the content of the
x-ic-after-cart-items page set as:
<div class="notice danger"> <h4>Important!!</h4> Please remember to enter the text for your engraving in the <strong>Notes or instructions</strong> field during checkout. </div>
Note that we used the notice class - refer to method 3 in article How do I display a notice in my Big Cartel shop? - to highlight this text as critical.