There are 22 managed variables, one per field in the Global Styles panel. They're only emitted when the field is set.
These Variables can be inserted into CSS with a proper CSS variable handler var(--sf-primary);
Colors (hex)
--sf-primary
--sf-secondary
--sf-accent
--sf-success
--sf-warning
--sf-error
Body
--sf-body-bg (hex)
--sf-body-color (hex)
--sf-body-font-size (px)
--sf-body-line-height (unitless)
--sf-body-font-family (web-safe font stack)
Heading (h1)
--sf-h1-color (hex)
--sf-h1-font-size (px)
--sf-h1-line-height (unitless)
--sf-h1-font-family (font stack)
Subheading (h2)
--sf-h2-color (hex)
--sf-h2-font-size (px)
--sf-h2-line-height (unitless)
--sf-h2-font-family (font stack)
Buttons (applied to button, .btn, input[type="submit"], input[type="button"])
--sf-btn-bg (hex)
--sf-btn-color (hex)
--sf-btn-radius (px)
Links (applied to a)
--sf-link-color (hex)
--sf-link-decoration (none or underline)