[Bug] `<shopify-account>` crashes WebKit on iOS 16 (EXC_BAD_ACCESS in RenderThemeIOS::systemColor due to Relative Color Syntax)

[simplenotezy]

Description:
On iOS/iPadOS 16.x devices, loading a storefront with <shopify-account> enabled causes an immediate WebContent process crash (EXC_BAD_ACCESS / SIGSEGV at 0x8).

Root Cause:
The Shadow DOM styles injected by <shopify-account> include CSS Relative Color Syntax with var() references on pseudo-elements:

.account-button__avatar::before {
  box-shadow: 0 4px 4px rgba(from var(--shopify-account-signed-in-avatar-color-background) r g b / .12);
}

On iOS 16 WebKit engines, evaluating dynamic CSS variables inside relative color expressions on pseudo-elements dereferences a null pointer in WebCore::RenderThemeIOS::systemColor.

Stack Trace from .ips Crash Log:

• WebCore::RenderThemeIOS::systemColor
• WebCore::CSSPropertyParserHelpers::consumeOriginColorRaw
• WebCore::CSSPropertyParserHelpers::parseRelativeRGBParametersRaw
• WebCore::Style::Builder::resolveVariableReferences
• WebCore::Style::TreeResolver::resolvePseudoElement

Suggested Fix for Shopify CDN:
Wrap relative color syntax inside @supports (color: rgb(from white r g b)) feature queries with solid RGBA fallbacks, or avoid relative color syntax on pseudo-elements in customer account web components.