Replaced .fond classes with tailwind background classes

src/lib/components/CsgBudgetView.svelte

src/lib/components/IrBudgetView.svelte

src/lib/components/parameters/ParameterView.svelte

src/routes/+page.svelte

src/routes/contribuer/+page.svelte

src/routes/parameters/[parameter]/edit/+page.svelte

src/routes/variables/[variable]/+page.svelte

tailwind.config.cjs