There's a quiet frustration in the question you're asking, and it's entirely justified. You've done everything right: opened a blank workbook, switched the theme to Office 2013-2022, and checked the Cell Styles for Headings 1. What you found is that the font reads Calibri (Body), not Calibri Light (Headings). And you're right to wonder why. The expectation, based on how that theme is supposed to behave, is that headings should carry a lighter, more distinct typeface. Instead, you're seeing the same font as your body text. That's not a quirk of your build. It's a real inconsistency in how Excel applies theme defaults, and it's worth understanding because it affects how your work presents itself.
Here's what's happening in practical terms. The Office 2013-2022 theme was designed with Calibri Light as the visual anchor for headings. That's the intent baked into the theme's definition. But what you're seeing suggests that the theme's heading styles are pulling from the body font slot rather than the heading font slot. That's not something you changed, and it's not something you did wrong. It's a default behavior that contradicts the theme's apparent design. For you, this means that every workbook you create with that theme is likely using a heavier, denser font for headings than the theme intends. It's a small detail, but in a spreadsheet where headings are your primary wayfinding tool, it matters. A heading should help you scan quickly. When it looks just like the body text, the visual hierarchy collapses.
The deeper point here is about trust. When a tool promises a theme, you should be able to rely on it. You didn't ask for a custom setup. You selected a standard option, and the software didn't deliver what it implied. That's not a failure on your part, and it's not a reason to stop exploring what Excel can do. It's a reason to check your defaults, not just once, but as part of your workflow. The fact that you noticed this and asked the question means you're paying attention to the details that make your spreadsheets clearer and more professional. That's the right instinct. The fix is straightforward: modify the Heading 1 style once, set the font to Calibri Light, and save it as your default template. But the bigger takeaway is that you can't always assume the theme does the work for you.
So here's the concrete action. Open a blank workbook, go to Cell Styles, right-click Heading 1, choose Modify, and check the font. If it says Calibri (Body), change it to Calibri Light. Then save that workbook as a template named Book.xltx in your personal templates folder. That way, every new workbook starts with the heading style you actually want. It's a five-minute fix that puts control back in your hands. You don't have to accept a default that doesn't match the tool's own design language. And the next time someone tells you a theme is just a theme, you'll know better.