feat: Convert to pure Astro CSS (no Tailwind)

- Removed Tailwind CSS dependency (19KB → 8.7KB CSS)
- Created native Astro CSS with CSS custom properties
- All utility classes using vanilla CSS
- Scoped component styles with Astro's built-in scoping
- Same green theme and design preserved
- Zero build dependencies for CSS
- Faster builds, smaller bundle
- True 'Astro way' of styling

node_modules/.bin/autoprefixer

@@ -1 +0,0 @@
-../autoprefixer/bin/autoprefixer

node_modules/.bin/baseline-browser-mapping

@@ -1 +0,0 @@
-../baseline-browser-mapping/dist/cli.cjs

node_modules/.bin/browserslist

@@ -1 +0,0 @@
-../browserslist/cli.js

node_modules/.bin/jiti

@@ -1 +0,0 @@
-../jiti/bin/jiti.js

node_modules/.bin/resolve

@@ -1 +0,0 @@
-../resolve/bin/resolve

node_modules/.bin/sucrase

@@ -1 +0,0 @@
-../sucrase/bin/sucrase

node_modules/.bin/sucrase-node

@@ -1 +0,0 @@
-../sucrase/bin/sucrase-node

node_modules/.bin/tailwind

@@ -1 +0,0 @@
-../tailwindcss/lib/cli.js

node_modules/.bin/tailwindcss

@@ -1 +0,0 @@
-../tailwindcss/lib/cli.js

node_modules/.bin/update-browserslist-db

@@ -1 +0,0 @@
-../update-browserslist-db/cli.js

node_modules/.bin/yaml

@@ -1 +0,0 @@
-../yaml/bin.mjs