consistent colorscheme in tailwind config

[sparrowsl]

as per the figma UI in #133 there are already specific colors to be used (~4 type of lime-green-ish)

but after inspecting the site I see bg-[#d1ea9a]/90 for the header in explore and bg-cyan-950 for the navigation
with a fixed color scheme inside the tailwind config we could get:

// ...
colors: {
    "brand-lime": #d1ea9a
    // other colors
}
// ...

now in the source code we could just reference the text-brand-lime/bg-brand-lime with some modifiers like bg-brand-lime/90 so now we only need to change one specific color and all other places will change with the update.

Or we just use the ones from tailwind,