diff --git a/bin/omarchy-theme-osc b/bin/omarchy-theme-osc
index 28f18388..8768df7c 100755
--- a/bin/omarchy-theme-osc
+++ b/bin/omarchy-theme-osc
@@ -17,21 +17,56 @@ awk -F= '
     return value
   }
 
+  function alias_color(target, source) {
+    if (colors[target] == "" && colors[source] != "") colors[target] = colors[source]
+  }
+
+  function emit_color(color_index, key) {
+    if (colors[key] != "") printf "\033]4;%d;%s\007", color_index, colors[key]
+  }
+
   {
     key = $1
     gsub(/^[[:space:]]+|[[:space:]]+$/, "", key)
     value = clean($2)
+    colors[key] = value
   }
 
-  key == "foreground" { printf "\033]10;%s\007", value }
-  key == "background" { printf "\033]11;%s\007", value }
-  key == "cursor" { printf "\033]12;%s\007", value }
-  key == "selection_background" { printf "\033]17;%s\007", value }
-  key == "selection_foreground" { printf "\033]19;%s\007", value }
-  key ~ /^color[0-9]+$/ {
-    color_index = substr(key, 6) + 0
-    if (color_index >= 0 && color_index <= 15) {
-      printf "\033]4;%d;%s\007", color_index, value
-    }
+  END {
+    alias_color("color0", "bg")
+    alias_color("color0", "background")
+    alias_color("color1", "red")
+    alias_color("color2", "green")
+    alias_color("color3", "yellow")
+    alias_color("color4", "blue")
+    alias_color("color5", "purple")
+    alias_color("color6", "cyan")
+    alias_color("color7", "fg")
+    alias_color("color7", "foreground")
+    alias_color("color8", "muted")
+    alias_color("color8", "dark_fg")
+    alias_color("color8", "foreground")
+    alias_color("color9", "bright_red")
+    alias_color("color9", "red")
+    alias_color("color10", "bright_green")
+    alias_color("color10", "green")
+    alias_color("color11", "bright_yellow")
+    alias_color("color11", "yellow")
+    alias_color("color12", "bright_blue")
+    alias_color("color12", "blue")
+    alias_color("color13", "bright_purple")
+    alias_color("color13", "purple")
+    alias_color("color14", "bright_cyan")
+    alias_color("color14", "cyan")
+    alias_color("color15", "bright_fg")
+    alias_color("color15", "foreground")
+
+    if (colors["foreground"] != "") printf "\033]10;%s\007", colors["foreground"]
+    if (colors["background"] != "") printf "\033]11;%s\007", colors["background"]
+    if (colors["cursor"] != "") printf "\033]12;%s\007", colors["cursor"]
+    if (colors["selection_background"] != "") printf "\033]17;%s\007", colors["selection_background"]
+    if (colors["selection_foreground"] != "") printf "\033]19;%s\007", colors["selection_foreground"]
+
+    for (i = 0; i <= 15; i++) emit_color(i, "color" i)
   }
 ' "$theme"
diff --git a/bin/omarchy-theme-set-gnome b/bin/omarchy-theme-set-gnome
index 8b0b1ddc..c2c6f610 100755
--- a/bin/omarchy-theme-set-gnome
+++ b/bin/omarchy-theme-set-gnome
@@ -8,9 +8,31 @@
 #   2. legacy `light.mode` file shipped beside the theme
 THEME_DIR=~/.config/omarchy/current/theme
 COLORS_FILE="$THEME_DIR/colors.toml"
+
+theme_color() {
+  local key="$1"
+
+  awk -F= -v key="$key" '
+    {
+      field = $1
+      gsub(/^[[:space:]]+|[[:space:]]+$/, "", field)
+      if (field == key) {
+        value = $2
+        gsub(/^[[:space:]]+|[[:space:]]+$/, "", value)
+        if (value ~ /^"/) {
+          sub(/^"/, "", value)
+          sub(/".*$/, "", value)
+        }
+        print value
+        exit
+      }
+    }
+  ' "$COLORS_FILE"
+}
+
 mode=""
-if [[ -f $COLORS_FILE ]] && command -v tomlq >/dev/null; then
-  mode=$(tomlq -r '.mode // empty' "$COLORS_FILE" 2>/dev/null)
+if [[ -f $COLORS_FILE ]]; then
+  mode=$(theme_color mode)
 fi
 if [[ -z $mode && -f $THEME_DIR/light.mode ]]; then
   mode="light"
diff --git a/bin/omarchy-theme-set-templates b/bin/omarchy-theme-set-templates
index 19a6b6d8..a9a09786 100755
--- a/bin/omarchy-theme-set-templates
+++ b/bin/omarchy-theme-set-templates
@@ -337,6 +337,20 @@ if [[ -f $COLORS_FILE ]]; then
   [[ ${THEME_COLORS[bright_blue]} ]]   || THEME_COLORS[bright_blue]=$(mix_color "${THEME_COLORS[blue]}" "#ffffff" 20%)
   [[ ${THEME_COLORS[bright_purple]} ]] || THEME_COLORS[bright_purple]=$(mix_color "${THEME_COLORS[purple]}" "#ffffff" 20%)
 
+  # Keep semantic themes compatible with user templates that still reference
+  # the legacy ANSI placeholders directly.
+  declare -A ansi_alias=(
+    [color0]=bg          [color1]=red           [color2]=green
+    [color3]=yellow      [color4]=blue          [color5]=purple
+    [color6]=cyan        [color7]=fg            [color8]=muted
+    [color9]=bright_red  [color10]=bright_green [color11]=bright_yellow
+    [color12]=bright_blue [color13]=bright_purple [color14]=bright_cyan
+    [color15]=bright_fg
+  )
+  for key in "${!ansi_alias[@]}"; do
+    [[ ${THEME_COLORS[$key]} ]] || THEME_COLORS[$key]="${THEME_COLORS[${ansi_alias[$key]}]}"
+  done
+
   # Resolve theme mode (dark|light) with this precedence:
   #   1. `mode` key in colors.toml
   #   2. legacy `light.mode` file shipped beside the theme
diff --git a/bin/omarchy-theme-set-tmux b/bin/omarchy-theme-set-tmux
index 4b778fdd..efb696d1 100755
--- a/bin/omarchy-theme-set-tmux
+++ b/bin/omarchy-theme-set-tmux
@@ -37,8 +37,11 @@ sync_theme_environment() {
 
 sync_colorfgbg() {
   local colorfgbg="15;0"
+  local mode
 
-  if [[ -f $CURRENT_THEME_PATH/light.mode ]]; then
+  mode=$(theme_color mode)
+
+  if [[ $mode == "light" ]] || [[ -z $mode && -f $CURRENT_THEME_PATH/light.mode ]]; then
     colorfgbg="0;15"
   fi
 
diff --git a/bin/omarchy-theme-set-vscode b/bin/omarchy-theme-set-vscode
index 1b44d0bf..569a9fcb 100755
--- a/bin/omarchy-theme-set-vscode
+++ b/bin/omarchy-theme-set-vscode
@@ -9,9 +9,14 @@ GENERATED_THEME="$HOME/.config/omarchy/current/theme/vscode-theme.json"
 # Install generated theme as a local extension for a given editor
 install_generated_extension() {
   local ext_dir="$1"
-  local theme_type
+  local theme_type ui_theme
 
   theme_type=$(jq -r '.type // "dark"' "$GENERATED_THEME")
+  if [[ $theme_type == "light" ]]; then
+    ui_theme="vs"
+  else
+    ui_theme="vs-dark"
+  fi
 
   mkdir -p "$ext_dir/themes"
   cp "$GENERATED_THEME" "$ext_dir/themes/omarchy-color-theme.json"
@@ -28,7 +33,7 @@ install_generated_extension() {
     "contributes": {
         "themes": [{
             "label": "Omarchy",
-            "uiTheme": "vs-${theme_type}",
+            "uiTheme": "$ui_theme",
             "path": "./themes/omarchy-color-theme.json"
         }]
     }
diff --git a/test/cli b/test/cli
index d4c14bb3..649bf33d 100755
--- a/test/cli
+++ b/test/cli
@@ -215,6 +215,7 @@ USER_THEMED="$PI_TMPDIR/.config/omarchy/themed"
 mkdir -p "$NEXT_THEME" "$CURRENT_THEME" "$USER_THEMED"
 
 cat >"$NEXT_THEME/colors.toml" <<'EOF'
+mode = "light"
 accent = "#336699"
 hyprland_active_border = "rgba(010203ee) rgba(040506ee) 45deg"
 cursor = "#ffffff"
@@ -253,12 +254,27 @@ fallback-shell={{ gradient_start missing accent }}
 fallback-shell-gradient={{ shell_gradient missing accent }}
 EOF
 
+cat >"$USER_THEMED/alias-test.txt.tpl" <<'EOF'
+color={{ color1 }}
+strip={{ color1_strip }}
+rgb={{ color1_rgb }}
+EOF
+
 OMARCHY_PATH="$ROOT" HOME="$PI_TMPDIR" "$ROOT/bin/omarchy-theme-set-templates"
 grep -qx 'mix=#808080' "$NEXT_THEME/mix-test.txt" || fail "theme template mix helper works"
 grep -qx 'strip=808080' "$NEXT_THEME/mix-test.txt" || fail "theme template mix_strip helper works"
 grep -qx 'rgb=128,128,128' "$NEXT_THEME/mix-test.txt" || fail "theme template mix_rgb helper works"
 pass "theme template color mix helpers work"
 
+grep -qx 'color=#ff0000' "$NEXT_THEME/alias-test.txt" || fail "theme template semantic aliases expose legacy colorN"
+grep -qx 'strip=ff0000' "$NEXT_THEME/alias-test.txt" || fail "theme template legacy colorN_strip works"
+grep -qx 'rgb=255,0,0' "$NEXT_THEME/alias-test.txt" || fail "theme template legacy colorN_rgb works"
+pass "theme template semantic aliases expose legacy colorN helpers"
+
+osc_summary=$("$ROOT/bin/omarchy-theme-osc" "$NEXT_THEME/colors.toml" | python -c 'import sys; data = sys.stdin.buffer.read(); print(data.count(b"]4;"), b"]4;1;#ff0000" in data, b"]4;15;#eeeeee" in data)')
+[[ $osc_summary == "16 True True" ]] || fail "theme OSC aliases semantic colors to ANSI palette"
+pass "theme OSC aliases semantic colors to ANSI palette"
+
 grep -qx 'hypr={ colors = { "rgba(010203ee)", "rgba(040506ee)" }, angle = 45 }' "$NEXT_THEME/gradient-test.txt" || fail "theme template hypr_gradient helper works"
 grep -qx 'shell=#010203' "$NEXT_THEME/gradient-test.txt" || fail "theme template gradient_start helper works"
 grep -qx 'shell-gradient=rgba(010203ee) rgba(040506ee) 45deg' "$NEXT_THEME/gradient-test.txt" || fail "theme template shell_gradient helper works"
@@ -296,6 +312,63 @@ HOME="$PI_TMPDIR" "$ROOT/bin/omarchy-theme-set-pi" --activate
 jq -e '.theme == "omarchy-system" and .model == "keep-me"' "$PI_TMPDIR/.pi/agent/settings.json" >/dev/null
 pass "pi theme activation preserves existing settings"
 
+cp "$NEXT_THEME/colors.toml" "$CURRENT_THEME/colors.toml"
+cp "$NEXT_THEME/vscode-theme.json" "$CURRENT_THEME/vscode-theme.json"
+
+FAKE_BIN="$PI_TMPDIR/fake-bin"
+mkdir -p "$FAKE_BIN"
+
+cat >"$FAKE_BIN/tmux" <<'EOF'
+#!/bin/bash
+case "$1" in
+  list-sessions)
+    [[ $2 == "-F" ]] && echo "session-1"
+    exit 0
+    ;;
+  set-environment|set-option|refresh-client)
+    echo "$*" >>"${TMUX_LOG:-/dev/null}"
+    exit 0
+    ;;
+  list-panes|list-clients)
+    exit 0
+    ;;
+  *)
+    exit 0
+    ;;
+esac
+EOF
+chmod +x "$FAKE_BIN/tmux"
+
+TMUX_LOG="$PI_TMPDIR/tmux.log" PATH="$FAKE_BIN:$ROOT/bin:$PATH" HOME="$PI_TMPDIR" "$ROOT/bin/omarchy-theme-set-tmux"
+grep -q 'set-environment -g COLORFGBG 0;15' "$PI_TMPDIR/tmux.log" || fail "tmux sync reads mode from colors.toml"
+pass "tmux sync reads mode from colors.toml"
+
+cat >"$FAKE_BIN/gsettings" <<'EOF'
+#!/bin/bash
+echo "$*" >>"${GSETTINGS_LOG:-/dev/null}"
+EOF
+chmod +x "$FAKE_BIN/gsettings"
+
+GSETTINGS_LOG="$PI_TMPDIR/gsettings.log" PATH="$FAKE_BIN:$ROOT/bin:$PATH" HOME="$PI_TMPDIR" "$ROOT/bin/omarchy-theme-set-gnome"
+grep -q 'org.gnome.desktop.interface color-scheme prefer-light' "$PI_TMPDIR/gsettings.log" || fail "gnome sync reads mode from colors.toml"
+pass "gnome sync reads mode from colors.toml"
+
+cat >"$FAKE_BIN/omarchy-cmd-present" <<'EOF'
+#!/bin/bash
+[[ $1 == "code" ]]
+EOF
+chmod +x "$FAKE_BIN/omarchy-cmd-present"
+
+cat >"$FAKE_BIN/omarchy-toggle-enabled" <<'EOF'
+#!/bin/bash
+exit 1
+EOF
+chmod +x "$FAKE_BIN/omarchy-toggle-enabled"
+
+PATH="$FAKE_BIN:$ROOT/bin:$PATH" HOME="$PI_TMPDIR" "$ROOT/bin/omarchy-theme-set-vscode"
+jq -e '.contributes.themes[0].uiTheme == "vs"' "$PI_TMPDIR/.vscode/extensions/omarchy-theme/package.json" >/dev/null || fail "vscode generated light theme uses VS Code light uiTheme"
+pass "vscode generated light theme uses VS Code light uiTheme"
+
 for binary in \
   omarchy-update \
   omarchy-theme-set \