diff --git a/README.md b/README.md
index b428399..1a8e1a6 100644
--- a/README.md
+++ b/README.md
@@ -1,19 +1,24 @@
 # Alacritty config builder
 
-Simple shell script to generate multiple Alacritty config files from a shared base.
+Simple shell script to generate Alacritty config file.
 
 ## Structure
 
 - `src/base.toml` contains common settings
-- Other files contain appearance or size variants
-- `build.sh` concatenates base + variant into final configs
+- `src/light.toml` contains light theme settings.
+- `src/dark.toml` contains dark theme settings.
+- `build.sh` concatenates base + variant into final config.
 
 ## Usage
 
 ```sh
+./build.sh dark
+./build.sh light
+
+# defaults to light.
 ./build.sh
 ```
 
-Generated files are written to `./`.
+Generated file is written to `./alacritty.toml`.
 
-Edit source files only. Generated files are disposable.
+**Edit source files only**.
diff --git a/build.sh b/build.sh
index b486d7b..99c18e9 100755
--- a/build.sh
+++ b/build.sh
@@ -1,11 +1,18 @@
 #!/bin/sh
+set -e
 
-SRC=./src
-OUT=.
+SRC_DIR=./src
+OUT_FILE=./alacritty.toml
 
-cat "$SRC/base.toml" "$SRC/default.toml"      > "$OUT/alacritty.toml"
-cat "$SRC/base.toml" "$SRC/small.toml"        > "$OUT/alacritty--small.toml"
-cat "$SRC/base.toml" "$SRC/light.toml"        > "$OUT/alacritty--light.toml"
-cat "$SRC/base.toml" "$SRC/light-small.toml"  > "$OUT/alacritty--light-small.toml"
-cat "$SRC/base.toml" "$SRC/light-large.toml"  > "$OUT/alacritty--light-large.toml"
+mode="${1:-light}"
+case "$mode" in
+light|dark) ;;
+*)
+  echo "Usage: $0 [light|dark]" >&2
+  exit 1
+  ;;
+esac
 
+theme="$SRC_DIR/$mode.toml"
+
+cat "$SRC_DIR/base.toml" "$theme" > "$OUT_FILE"
diff --git a/src/base.toml b/src/base.toml
index b17e045..8686696 100644
--- a/src/base.toml
+++ b/src/base.toml
@@ -9,6 +9,33 @@ TERM = "alacritty"
 animation = "EaseOutExpo"
 duration = 0
 
+[font]
+size = 11.0
+
+[font.bold]
+family = "SourceCodePro"
+style = "Bold"
+
+[font.bold_italic]
+family = "OperatorMono"
+style = "Medium Italic"
+
+[font.glyph_offset]
+x = 0
+y = 0
+
+[font.italic]
+family = "SourceCodePro"
+style = "Semibold Italic"
+
+[font.normal]
+family = "SourceCodePro"
+style = "Semibold"
+
+[font.offset]
+x = -1
+y = 0
+
 [[keyboard.bindings]]
 action = "Paste"
 key = "V"
diff --git a/src/small.toml b/src/dark.toml
similarity index 54%
rename from src/small.toml
rename to src/dark.toml
index 5bd2ab1..02bf2cf 100644
--- a/src/small.toml
+++ b/src/dark.toml
@@ -21,30 +21,3 @@ yellow = "#e1a574"
 [colors.primary]
 background = "#27292c"
 foreground = "#a9abaa"
-
-[font]
-size = 9.0
-
-[font.bold]
-family = "SourceCodePro"
-style = "Bold"
-
-[font.bold_italic]
-family = "OperatorMono"
-style = "Medium Italic"
-
-[font.glyph_offset]
-x = 0
-y = 0
-
-[font.italic]
-family = "SourceCodePro"
-style = "Semibold Italic"
-
-[font.normal]
-family = "SourceCodePro"
-style = "Semibold"
-
-[font.offset]
-x = -1
-y = 0
diff --git a/src/default.toml b/src/default.toml
deleted file mode 100644
index c3b5e60..0000000
--- a/src/default.toml
+++ /dev/null
@@ -1,50 +0,0 @@
-[colors.bright]
-black = "#484c52"
-blue = "#96b1c9"
-cyan = "#9fc9c3"
-green = "#dffebe"
-magenta = "#bfa5c7"
-red = "#d27c7b"
-white = "#fcf7e2"
-yellow = "#f0d189"
-
-[colors.normal]
-black = "#35383b"
-blue = "#7693ac"
-cyan = "#749e99"
-green = "#769972"
-magenta = "#977ba0"
-red = "#b05655"
-white = "#848b92"
-yellow = "#e1a574"
-
-[colors.primary]
-background = "#27292c"
-foreground = "#a9abaa"
-
-[font]
-size = 11.0
-
-[font.bold]
-family = "SourceCodePro"
-style = "Bold"
-
-[font.bold_italic]
-family = "OperatorMono"
-style = "Medium Italic"
-
-[font.glyph_offset]
-x = 0
-y = 0
-
-[font.italic]
-family = "SourceCodePro"
-style = "Semibold Italic"
-
-[font.normal]
-family = "SourceCodePro"
-style = "Semibold"
-
-[font.offset]
-x = -1
-y = 0
diff --git a/src/light-large.toml b/src/light-large.toml
deleted file mode 100644
index e0fcab2..0000000
--- a/src/light-large.toml
+++ /dev/null
@@ -1,54 +0,0 @@
-[colors.bright]
-black = "0xbcbcbc"
-blue = "0xd75f00"
-cyan = "0x005faf"
-green = "0xd70087"
-magenta = "0xd75f00"
-red = "0xd70000"
-white = "0x005f87"
-yellow = "0x8700af"
-
-[colors.cursor]
-cursor = "0x878787"
-text = "0xeeeeee"
-
-[colors.normal]
-black = "0xeeeeee"
-blue = "0x0087af"
-cyan = "0x005f87"
-green = "0x008700"
-magenta = "0x878787"
-red = "0xaf0000"
-white = "0x444444"
-yellow = "0x5f8700"
-
-[colors.primary]
-background = "0xeeeeee"
-foreground = "0x878787"
-
-[font]
-size = 13.0
-
-[font.bold]
-family = "SourceCodePro"
-style = "Bold"
-
-[font.bold_italic]
-family = "OperatorMono"
-style = "Medium Italic"
-
-[font.glyph_offset]
-x = 0
-y = 0
-
-[font.italic]
-family = "SourceCodePro"
-style = "SemiBold Italic"
-
-[font.normal]
-family = "SourceCodePro"
-style = "SemiBold"
-
-[font.offset]
-x = -1
-y = 0
diff --git a/src/light-small.toml b/src/light-small.toml
deleted file mode 100644
index 6ace2d0..0000000
--- a/src/light-small.toml
+++ /dev/null
@@ -1,54 +0,0 @@
-[colors.bright]
-black = "0xbcbcbc"
-blue = "0xd75f00"
-cyan = "0x005faf"
-green = "0xd70087"
-magenta = "0xd75f00"
-red = "0xd70000"
-white = "0x005f87"
-yellow = "0x8700af"
-
-[colors.cursor]
-cursor = "0x878787"
-text = "0xeeeeee"
-
-[colors.normal]
-black = "0xeeeeee"
-blue = "0x0087af"
-cyan = "0x005f87"
-green = "0x008700"
-magenta = "0x878787"
-red = "0xaf0000"
-white = "0x444444"
-yellow = "0x5f8700"
-
-[colors.primary]
-background = "0xeeeeee"
-foreground = "0x878787"
-
-[font]
-size = 9.0
-
-[font.bold]
-family = "SourceCodePro"
-style = "Bold"
-
-[font.bold_italic]
-family = "OperatorMono"
-style = "Medium Italic"
-
-[font.glyph_offset]
-x = 0
-y = 0
-
-[font.italic]
-family = "SourceCodePro"
-style = "SemiBold Italic"
-
-[font.normal]
-family = "SourceCodePro"
-style = "SemiBold"
-
-[font.offset]
-x = -1
-y = 0
diff --git a/src/light.toml b/src/light.toml
index 7dc1e3d..aa82c0a 100644
--- a/src/light.toml
+++ b/src/light.toml
@@ -25,30 +25,3 @@ yellow = "0x5f8700"
 [colors.primary]
 background = "0xeeeeee"
 foreground = "0x878787"
-
-[font]
-size = 11.0
-
-[font.bold]
-family = "SourceCodePro"
-style = "Bold"
-
-[font.bold_italic]
-family = "OperatorMono"
-style = "Medium Italic"
-
-[font.glyph_offset]
-x = 0
-y = 0
-
-[font.italic]
-family = "SourceCodePro"
-style = "SemiBold Italic"
-
-[font.normal]
-family = "SourceCodePro"
-style = "SemiBold"
-
-[font.offset]
-x = -1
-y = 0