style: Split out and fixes

hm/theme/default.nix

@@ -0,0 +1,24 @@
+{ pkgs, config, lib, ... }:
+let
+  basetheme = "solarized";
+in
+{
+  config = {
+    # Setting a custom base16 theme via nixvim is required so feline works, and
+    # because stylix makes a config that otherwise only works with dark
+    # polarity.
+    programs.nixvim.colorschemes.base16.colorscheme = "${basetheme}-${config.frogeye.polarity}";
+
+    stylix = {
+      base16Scheme = "${pkgs.base16-schemes}/share/themes/${basetheme}-${config.frogeye.polarity}.yaml";
+      fonts = {
+        monospace = {
+          package = pkgs.nerdfonts.override {
+            fonts = [ "DejaVuSansMono" ]; # Choose from https://github.com/NixOS/nixpkgs/blob/6ba3207643fd27ffa25a172911e3d6825814d155/pkgs/data/fonts/nerdfonts/shas.nix
+          };
+          name = "DejaVuSansM Nerd Font";
+        };
+      };
+    };
+  };
+}