feat: introduce theme management and performance improvements (#7)

internal/theme/one_dark.go

@@ -0,0 +1,24 @@
+package theme
+
+// one dark theme (atom editor)
+// https://github.com/atom/atom/tree/master/packages/one-dark-syntax
+var paletteOneDark = Palette{
+	Name: "one-dark",
+
+	Fg:       "#abb2bf", // foreground
+	FgMuted:  "#9da5b4", // foreground muted
+	FgSubtle: "#5c6370", // comment
+	Bg:       "#282c34", // background
+	BgMuted:  "#21252b", // gutter background
+	Border:   "#3e4451", // selection
+
+	Red:     "#e06c75",
+	Green:   "#98c379",
+	Yellow:  "#e5c07b",
+	Blue:    "#61afef",
+	Magenta: "#c678dd", // purple
+	Cyan:    "#56b6c2",
+	Orange:  "#d19a66",
+	Gray:    "#5c6370", // comment
+}
+