Create PostLine branding

docs/handbook/branding/.nav.yml

@@ -4,4 +4,5 @@ nav:
   - starcatsys.md
   - docshub.md
   - sourcecamp.md
+  - postline.md
   - stagelink.md

docs/handbook/branding/postline.md

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+# PostLine
+
+# Logo
+[:material-folder-lock: Logos > PostLine](https://cloud.starcatsys.net/f/2025)
+
+Adapted from [Group Mail](https://thenounproject.com/icon/group-mail-1571732/) by [Smashicons](https://thenounproject.com/creator/smashicons/) from Noun Project.
+
+## Colors
+### Logo Colors
+**Logo Background**: `#1E2A38` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/1E2A38?style=circle'/> (midnight blue)  
+**Envelope White**: `#FFFFFF` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/FFFFFF?style=circle'/>  
+**Envelope Blue**: `#4DA8DA` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/4DA8DA?style=circle'/> (sky blue)  
+**Text**: `#FFFFFF` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/FFFFFF?style=circle'/>  
+
+### Website Colors
+**Background**: `#F5F7FA` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/F5F7FA?style=circle'/> (warm gray)  
+**Headings/titles**: `#1E2A38` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/1E2A38?style=circle'/> (midnight blue)  
+**Body text**: `#6B7C93` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/6B7C93?style=circle'/> (slate gray)  
+**Buttons/CTAs**: `#FF6B6B` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/FF6B6B?style=circle'/> (soft coral)  
+**Links and highlights**: `#2EC4B6` <img valign='middle' alt='blue' src='https://readme-swatches.vercel.app/2EC4B6?style=circle'/> (mint green)  
+
+
+## Backgrounds
+
+## Fonts
+### Logo Font
+*Cabin* - medium
+*Cabin* by Impallari Type, Rodrigo Fuenzalida: [:octicons-link-external-16: Google Fonts - Cabin](https://fonts.google.com/specimen/Cabin)