Add transparent logo variants for light and dark themes

- Light theme: transparent background, original black outlines and blue curve
- Dark theme: transparent background, white outlines, light blue curve, dark screen area
- Updated navbar logo and hero image to use theme-specific variants

Author: apetros

astro.config.mjs

@@ -17,7 +17,8 @@ export default defineConfig({
 			title: 'STEPSS',
 			description: 'Static and Transient Electric Power Systems Simulation — Documentation',
 			logo: {
-				src: './src/assets/logo.png',
+				light: './src/assets/logo-light.png',
+				dark: './src/assets/logo-dark.png',
 				replacesTitle: false,
 			},
 			social: [

src/assets/logo-dark-tmp.png

@@ -5,7 +5,8 @@ template: splash
 hero:
   tagline: A comprehensive power system simulation suite for static and dynamic analysis of electrical grids, developed by the Sustainable Power Systems Lab (SPS-L).
   image:
-    file: ../../assets/logo.png
+    dark: ../../assets/logo-dark.png
+    light: ../../assets/logo-light.png
   actions:
     - text: Get Started
       link: /getting-started/overview/