fix(email): inherit button brand colors across render targets

packages/email-renderer/src/email.ts

@@ -80,7 +80,7 @@ const head = (document: BlockDocument, body: string, direction: "ltr" | "rtl") =
   return `<!doctype html><html lang="${escapeHtml(document.meta.lang)}" dir="${direction}"><head><meta charset="utf-8"><meta name="viewport" content="width=device-width,initial-scale=1"><meta name="x-apple-disable-message-reformatting"><meta name="color-scheme" content="light dark"><title>${escapeHtml(document.meta.subject)}</title><style>a{color:${linkColor}}@media only screen and (max-width:480px){.wrn-email{width:100%!important}.wrn-columns{display:block!important}.wrn-column{display:block!important;width:100%!important}}</style></head><body style="margin:0;padding:0;color:${textColor};font-family:${fontFamily};">${document.meta.preheader ? `<div style="display:none;max-height:0;overflow:hidden;opacity:0;">${escapeHtml(document.meta.preheader)}</div>` : ""}${body}</body></html>`;
 };
 const ampHead = (document: BlockDocument, body: string, direction: "ltr" | "rtl") => {
-  const layoutCss = (node: BlockDocument["root"]): string => ampLayoutCss(node) + Object.values(node.slots).flat().map(layoutCss).join("");
+  const layoutCss = (node: BlockDocument["root"]): string => ampLayoutCss(node, String(document.root.props.linkColor ?? "#2563eb")) + Object.values(node.slots).flat().map(layoutCss).join("");
   const props = document.root.props as Record<string, unknown>;
   const css = `@media only screen and (max-width:480px){.email-body .wrn-columns{display:block}.email-body .wrn-column{display:block;width:100%}}.marketing-image img{object-fit:contain}body{margin:0;color:${props.textColor ?? "#111827"};font-family:${props.fontFamily ?? "Arial, sans-serif"}}a{color:${props.linkColor ?? "#2563eb"}}.email-bg{background:${props.background ?? "#f3f4f6"}}.email-body{max-width:${props.width ?? "600"}px;width:100%;background:${props.contentBackground ?? "#ffffff"}}`;
   return `<!doctype html><html amp4email data-css-strict lang="${escapeHtml(document.meta.lang)}" dir="${direction}"><head><meta charset="utf-8"><script async src="https://cdn.ampproject.org/v0.js"></script><style amp4email-boilerplate>body{visibility:hidden}</style><style amp-custom>${css}${layoutCss(document.root)}.button{background:#2563eb;border-radius:6px;color:#fff;display:inline-block;font-weight:700;padding:12px 20px;text-decoration:none}</style></head><body>${body}</body></html>`;
@@ -138,6 +138,7 @@ export async function renderEmail(
     timezone: options.timezone ?? "UTC",
     direction: options.direction ?? "ltr",
     countdownImageUrl: options.countdownImageUrl,
+    brandLinkColor: String(source.root.props.linkColor ?? "#2563eb"),
   };
   const [htmlResult, textResult, mjmlResult] = await Promise.all([
     renderTree(source, emailKind, registry, { ...base, target: "emailHtml", data: options.variables }),