fix: restore coral accent color with AA-accessible shade

Revert accent from SuperDoc Blue (#1355FF) back to coral (#c1463a),
preserving the site's original identity. The new shade passes WCAG AA
on all theme backgrounds (4.99:1 on white, 4.58:1 on tertiary).
Update brand.md and webmanifest theme_color accordingly.

Author: caio-pizzol

apps/web/public/site.webmanifest

@@ -6,7 +6,7 @@
 		{ "src": "/android-chrome-192x192.png", "sizes": "192x192", "type": "image/png" },
 		{ "src": "/android-chrome-512x512.png", "sizes": "512x512", "type": "image/png" }
 	],
-	"theme_color": "#1355FF",
+	"theme_color": "#c1463a",
 	"background_color": "#ffffff",
 	"display": "standalone"
 }

apps/web/src/index.css

@@ -1,11 +1,11 @@
 @import "tailwindcss";
 
-/* ooxml.dev theme - Blue */
+/* ooxml.dev theme - Coral */
 :root {
-	/* SuperDoc Blue accent */
-	--color-accent: #1355ff;
-	--color-accent-hover: #0f44cc;
-	--color-accent-light: #eff4ff;
+	/* Coral accent (AA-accessible on all theme backgrounds) */
+	--color-accent: #c1463a;
+	--color-accent-hover: #a33b31;
+	--color-accent-light: #fef2f0;
 
 	/* Backgrounds */
 	--color-bg-primary: #ffffff;
@@ -63,8 +63,8 @@ body {
 }
 
 .note-info {
-	background-color: #eff4ff;
-	border-color: #bfdbfe;
+	background-color: #fef2f0;
+	border-color: #fecaca;
 }
 
 .note-tip {

brand.md

@@ -206,10 +206,10 @@ _Use on homepage hero, social bios, link previews._
 
 ### Colors
 
-ooxml.dev inherits SuperDoc's color system as a sub-brand, with adjustments for a documentation-first context.
+ooxml.dev uses its own coral accent, distinct from SuperDoc's blue, to establish an independent identity as a reference site.
 
-**Primary — SuperDoc Blue**
-`#1355FF` — Links, interactive elements, active states. Connects ooxml.dev visually to SuperDoc.
+**Primary — Coral**
+`#C1463A` — Links, buttons, interactive elements, active states. An accessible shade of the original coral (4.99:1 on white, 4.58:1 on tertiary backgrounds).
 
 **Accent — Spec Gold**
 `#F59E0B` (amber-500) — Implementation notes, callout badges, warning states. Signals "attention — this is the insight you came for."
@@ -219,7 +219,7 @@ ooxml.dev inherits SuperDoc's color system as a sub-brand, with adjustments for
 |---|---|---|
 | Critical note | `#ED4337` | Critical implementation notes — things that break |
 | Warning note | `#F59E0B` | Non-obvious behavior, surprising gotchas |
-| Info note | `#1355FF` | Context and background |
+| Info note | `#C1463A` | Context and background |
 | Tip note | `#00853D` | Helpful shortcuts and techniques |
 | Text primary | `#212121` | Headings, body copy |
 | Text secondary | `#666666` | Supporting text, metadata |