Colors... We'll need a new space.

src/AppDelegate.swift

@@ -589,12 +589,12 @@ class AppDelegate: NSObject, NSApplicationDelegate, NSMenuItemValidation {
         let mode = ConfigManager.shared.themeMode
         let name: String
         switch mode {
-        case "dark": name = "mocha"
+        case "dark": name = "kicad"
         case "light": name = "latte"
         default:
             let appearance = NSApp.effectiveAppearance
             let isDark = appearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua
-            name = isDark ? "mocha" : "latte"
+            name = isDark ? "kicad" : "latte"
         }
         viewport?.setTheme(name)
     }

src/Theme.swift

@@ -60,6 +60,35 @@ struct Theme {
         rosewater: NSColor(red: 0.961, green: 0.761, blue: 0.765, alpha: 1)
     )
 
+    static let kicad = CatppuccinPalette(
+        base:      NSColor(red: 0.090, green: 0.094, blue: 0.114, alpha: 1),
+        mantle:    NSColor(red: 0.075, green: 0.078, blue: 0.102, alpha: 1),
+        crust:     NSColor(red: 0.059, green: 0.059, blue: 0.059, alpha: 1),
+        surface0:  NSColor(red: 0.102, green: 0.110, blue: 0.125, alpha: 1),
+        surface1:  NSColor(red: 0.122, green: 0.126, blue: 0.141, alpha: 1),
+        surface2:  NSColor(red: 0.133, green: 0.141, blue: 0.149, alpha: 1),
+        overlay0:  NSColor(red: 0.361, green: 0.368, blue: 0.418, alpha: 1),
+        overlay1:  NSColor(red: 0.449, green: 0.453, blue: 0.499, alpha: 1),
+        overlay2:  NSColor(red: 0.548, green: 0.545, blue: 0.598, alpha: 1),
+        text:      NSColor(red: 0.965, green: 0.954, blue: 0.969, alpha: 1),
+        subtext0:  NSColor(red: 0.679, green: 0.668, blue: 0.725, alpha: 1),
+        subtext1:  NSColor(red: 0.824, green: 0.813, blue: 0.852, alpha: 1),
+        red:       NSColor(red: 0.914, green: 0.376, blue: 0.376, alpha: 1),
+        maroon:    NSColor(red: 0.949, green: 0.416, blue: 0.584, alpha: 1),
+        peach:     NSColor(red: 0.965, green: 0.533, blue: 0.404, alpha: 1),
+        yellow:    NSColor(red: 0.988, green: 0.831, blue: 0.349, alpha: 1),
+        green:     NSColor(red: 0.403, green: 0.972, blue: 0.534, alpha: 1),
+        teal:      NSColor(red: 0.310, green: 1.000, blue: 0.882, alpha: 1),
+        sky:       NSColor(red: 0.403, green: 0.813, blue: 0.972, alpha: 1),
+        sapphire:  NSColor(red: 0.384, green: 0.635, blue: 0.949, alpha: 1),
+        blue:      NSColor(red: 0.337, green: 0.475, blue: 0.988, alpha: 1),
+        lavender:  NSColor(red: 1.000, green: 0.718, blue: 0.937, alpha: 1),
+        mauve:     NSColor(red: 0.635, green: 0.282, blue: 0.980, alpha: 1),
+        pink:      NSColor(red: 0.973, green: 0.345, blue: 0.718, alpha: 1),
+        flamingo:  NSColor(red: 0.965, green: 0.533, blue: 0.404, alpha: 1),
+        rosewater: NSColor(red: 0.984, green: 0.639, blue: 0.757, alpha: 1)
+    )
+
     static let latte = CatppuccinPalette(
         base:      NSColor(red: 0.937, green: 0.929, blue: 0.961, alpha: 1),
         mantle:    NSColor(red: 0.906, green: 0.898, blue: 0.941, alpha: 1),
@@ -92,12 +121,12 @@ struct Theme {
     static var current: CatppuccinPalette {
         let mode = ConfigManager.shared.themeMode
         switch mode {
-        case "dark": return mocha
+        case "dark": return kicad
         case "light": return latte
         default:
             let appearance = NSApp.effectiveAppearance
             let isDark = appearance.bestMatch(from: [.darkAqua, .aqua]) == .darkAqua
-            return isDark ? mocha : latte
+            return isDark ? kicad : latte
         }
     }
 

viewport/src/palette.rs

@@ -60,6 +60,38 @@ pub static MOCHA: Palette = Palette {
     crust:     Color::from_rgb(0.067, 0.067, 0.106),
 };
 
+/// KiCad-inspired dark — near-black background, saturated accents, high
+/// contrast. The signature KiCad schematic-editor feel: vivid greens,
+/// bright cyans, punchy reds and yellows on a deep navy base.
+pub static KICAD: Palette = Palette {
+    rosewater: Color::from_rgb(0.984, 0.639, 0.757),
+    flamingo:  Color::from_rgb(0.965, 0.533, 0.404),
+    pink:      Color::from_rgb(0.973, 0.345, 0.718),
+    mauve:     Color::from_rgb(0.635, 0.282, 0.980),
+    red:       Color::from_rgb(0.914, 0.376, 0.376),
+    maroon:    Color::from_rgb(0.949, 0.416, 0.584),
+    peach:     Color::from_rgb(0.965, 0.533, 0.404),
+    yellow:    Color::from_rgb(0.988, 0.831, 0.349),
+    green:     Color::from_rgb(0.403, 0.972, 0.534),
+    teal:      Color::from_rgb(0.310, 1.000, 0.882),
+    sky:       Color::from_rgb(0.403, 0.813, 0.972),
+    sapphire:  Color::from_rgb(0.384, 0.635, 0.949),
+    blue:      Color::from_rgb(0.337, 0.475, 0.988),
+    lavender:  Color::from_rgb(1.000, 0.718, 0.937),
+    text:      Color::from_rgb(0.965, 0.954, 0.969),
+    subtext1:  Color::from_rgb(0.824, 0.813, 0.852),
+    subtext0:  Color::from_rgb(0.679, 0.668, 0.725),
+    overlay2:  Color::from_rgb(0.548, 0.545, 0.598),
+    overlay1:  Color::from_rgb(0.449, 0.453, 0.499),
+    overlay0:  Color::from_rgb(0.361, 0.368, 0.418),
+    surface2:  Color::from_rgb(0.133, 0.141, 0.149),
+    surface1:  Color::from_rgb(0.122, 0.126, 0.141),
+    surface0:  Color::from_rgb(0.102, 0.110, 0.125),
+    base:      Color::from_rgb(0.090, 0.094, 0.114),
+    mantle:    Color::from_rgb(0.075, 0.078, 0.102),
+    crust:     Color::from_rgb(0.059, 0.059, 0.059),
+};
+
 pub static LATTE: Palette = Palette {
     rosewater: Color::from_rgb(0.863, 0.541, 0.471),
     flamingo:  Color::from_rgb(0.867, 0.471, 0.471),
@@ -105,7 +137,8 @@ pub fn is_dark() -> bool {
 pub fn set_theme(name: &str) {
     let (pal, dark) = match name {
         "latte" | "light" => (&LATTE, false),
-        _ => (&MOCHA, true),
+        "kicad" => (&KICAD, true),
+        _ => (&KICAD, true),
     };
     CURRENT.with(|c| *c.borrow_mut() = pal);
     IS_DARK.with(|d| *d.borrow_mut() = dark);

viewport/src/syntax.rs

@@ -1,3 +1,4 @@
+use std::collections::HashMap;
 use std::ops::Range;
 
 use iced_wgpu::core::text::highlighter;
@@ -32,6 +33,15 @@ const COR_OPERATOR: u8 = 62;
 const COR_BRACKET: u8 = 63;
 const COR_TYPE_ANN: u8 = 64;
 
+// Per-identifier rainbow. Each user-introduced name (let, fn, params, for var,
+// math-form fn def) gets one of eight palette slots, picked with a stride
+// that avoids adjacent colors landing on consecutive identifiers. Subsequent
+// references resolve to the same slot so the name reads the same color
+// throughout the document.
+const USER_IDENT_BASE: u8 = 70;
+const USER_IDENT_PALETTE_SIZE: u8 = 8;
+const USER_IDENT_HOP: u32 = 3;
+
 const MD_HEADING_MARKER: u8 = 26;
 const MD_H1: u8 = 27;
 const MD_H2: u8 = 28;
@@ -92,6 +102,7 @@ pub struct SyntaxHighlighter {
     in_fenced_code: bool,
     current_line: usize,
     line_decors: Vec<LineDecor>,
+    user_idents: HashMap<String, u8>,
 }
 
 impl SyntaxHighlighter {
@@ -132,6 +143,87 @@ impl SyntaxHighlighter {
 
         self.in_fenced_code = false;
         self.current_line = 0;
+
+        self.scan_user_idents(source);
+    }
+
+    /// Walk the source, find every identifier introduction site (let, fn,
+    /// for, math-form fn def, params), and assign each unique name a slot
+    /// in the user-ident rainbow. Subsequent references in `highlight_cordial`
+    /// look the name up here.
+    fn scan_user_idents(&mut self, source: &str) {
+        self.user_idents.clear();
+        let mut next_slot: u32 = 0;
+
+        for line in source.split('\n') {
+            let trimmed = line.trim_start();
+            let bytes = trimmed.as_bytes();
+
+            // `let IDENT...`
+            if let Some(rest) = trimmed.strip_prefix("let ") {
+                let mut i = 0;
+                let rb = rest.as_bytes();
+                while i < rb.len() && rb[i] == b' ' { i += 1; }
+                let name_start = i;
+                while i < rb.len() && (rb[i].is_ascii_alphanumeric() || rb[i] == b'_') { i += 1; }
+                if i > name_start {
+                    assign_user_ident(&mut self.user_idents, &mut next_slot, &rest[name_start..i]);
+                }
+                while i < rb.len() && rb[i] == b' ' { i += 1; }
+                if i < rb.len() && rb[i] == b'(' {
+                    extract_paren_idents(&rest[i + 1..], &mut self.user_idents, &mut next_slot);
+                }
+                continue;
+            }
+
+            // `fn IDENT(...)`
+            if let Some(rest) = trimmed.strip_prefix("fn ") {
+                let mut i = 0;
+                let rb = rest.as_bytes();
+                while i < rb.len() && rb[i] == b' ' { i += 1; }
+                let name_start = i;
+                while i < rb.len() && (rb[i].is_ascii_alphanumeric() || rb[i] == b'_') { i += 1; }
+                if i > name_start {
+                    assign_user_ident(&mut self.user_idents, &mut next_slot, &rest[name_start..i]);
+                }
+                while i < rb.len() && rb[i] == b' ' { i += 1; }
+                if i < rb.len() && rb[i] == b'(' {
+                    extract_paren_idents(&rest[i + 1..], &mut self.user_idents, &mut next_slot);
+                }
+                continue;
+            }
+
+            // `for IDENT in ...`
+            if let Some(rest) = trimmed.strip_prefix("for ") {
+                let rb = rest.as_bytes();
+                let mut i = 0;
+                while i < rb.len() && rb[i] == b' ' { i += 1; }
+                let name_start = i;
+                while i < rb.len() && (rb[i].is_ascii_alphanumeric() || rb[i] == b'_') { i += 1; }
+                if i > name_start {
+                    assign_user_ident(&mut self.user_idents, &mut next_slot, &rest[name_start..i]);
+                }
+                continue;
+            }
+
+            // `IDENT(...) = ...` math-form fn def, OR `IDENT = ...` assignment
+            let mut i = 0;
+            let name_start = i;
+            while i < bytes.len() && (bytes[i].is_ascii_alphanumeric() || bytes[i] == b'_') { i += 1; }
+            if i > name_start {
+                let name = &trimmed[name_start..i];
+                let mut j = i;
+                while j < bytes.len() && bytes[j] == b' ' { j += 1; }
+                if j < bytes.len() {
+                    if bytes[j] == b'(' {
+                        assign_user_ident(&mut self.user_idents, &mut next_slot, name);
+                        extract_paren_idents(&trimmed[j + 1..], &mut self.user_idents, &mut next_slot);
+                    } else if bytes[j] == b'=' && (j + 1 >= bytes.len() || bytes[j + 1] != b'=') {
+                        assign_user_ident(&mut self.user_idents, &mut next_slot, name);
+                    }
+                }
+            }
+        }
     }
 
     fn highlight_markdown(&self, line: &str) -> Vec<(Range<usize>, SyntaxHighlight)> {
@@ -204,7 +296,50 @@ impl SyntaxHighlighter {
 /// spans. Idempotent, single-pass; each branch either consumes a whole
 /// token or advances one byte. Unknown bytes get no highlight (they fall
 /// through to the editor's default text color).
-fn highlight_cordial(line: &str) -> Vec<(Range<usize>, SyntaxHighlight)> {
+fn assign_user_ident(map: &mut HashMap<String, u8>, slot: &mut u32, name: &str) {
+    if name.is_empty()
+        || is_cordial_keyword(name)
+        || is_cordial_builtin(name)
+        || is_cordial_type_annotation(name)
+        || name == "pi"
+        || name == "where"
+        || name == "from"
+        || name == "solve"
+        || map.contains_key(name)
+    {
+        return;
+    }
+    let color_idx = ((*slot * USER_IDENT_HOP) % USER_IDENT_PALETTE_SIZE as u32) as u8;
+    map.insert(name.to_string(), color_idx);
+    *slot += 1;
+}
+
+fn extract_paren_idents(s: &str, map: &mut HashMap<String, u8>, slot: &mut u32) {
+    let bytes = s.as_bytes();
+    let mut i = 0;
+    let mut depth: i32 = 1;
+    while i < bytes.len() && depth > 0 {
+        match bytes[i] {
+            b'(' => { depth += 1; i += 1; }
+            b')' => { depth -= 1; i += 1; }
+            b':' => {
+                // Skip the type identifier that follows; type names belong
+                // to the type-annotation color, not the user-ident rainbow.
+                i += 1;
+                while i < bytes.len() && (bytes[i] == b' ' || bytes[i] == b'\t') { i += 1; }
+                while i < bytes.len() && (bytes[i].is_ascii_alphanumeric() || bytes[i] == b'_') { i += 1; }
+            }
+            c if c.is_ascii_alphabetic() || c == b'_' => {
+                let start = i;
+                while i < bytes.len() && (bytes[i].is_ascii_alphanumeric() || bytes[i] == b'_') { i += 1; }
+                assign_user_ident(map, slot, &s[start..i]);
+            }
+            _ => i += 1,
+        }
+    }
+}
+
+fn highlight_cordial(line: &str, user_idents: &HashMap<String, u8>) -> Vec<(Range<usize>, SyntaxHighlight)> {
     let bytes = line.as_bytes();
     let len = bytes.len();
     let mut spans: Vec<(Range<usize>, SyntaxHighlight)> = Vec::new();
@@ -317,9 +452,7 @@ fn highlight_cordial(line: &str) -> Vec<(Range<usize>, SyntaxHighlight)> {
             continue;
         }
 
-        // Identifier → keyword / builtin / plain. Plain idents get no
+        // Identifier → keyword / builtin / type-annotation / user-rainbow.
-        // highlight so user-defined names stay in the default editor
-        // color — keeps the document from looking like confetti.
         if is_ident_byte(c) && !c.is_ascii_digit() {
             let start = i;
             while i < len && is_ident_byte(bytes[i]) { i += 1; }
@@ -329,9 +462,9 @@ fn highlight_cordial(line: &str) -> Vec<(Range<usize>, SyntaxHighlight)> {
             } else if is_cordial_builtin(word) {
                 spans.push((start..i, SyntaxHighlight { kind: COR_BUILTIN_FN }));
             } else if is_cordial_type_annotation(word) && last_token_is_colon(&spans) {
-                // Type annotation immediately after `:` in a `let x: T = …`
-                // reads the type name; give it the yellow/type color.
                 spans.push((start..i, SyntaxHighlight { kind: COR_TYPE_ANN }));
+            } else if let Some(&slot) = user_idents.get(word) {
+                spans.push((start..i, SyntaxHighlight { kind: USER_IDENT_BASE + slot }));
             }
             continue;
         }
@@ -682,6 +815,7 @@ impl highlighter::Highlighter for SyntaxHighlighter {
             in_fenced_code: false,
             current_line: 0,
             line_decors: Vec::new(),
+            user_idents: HashMap::new(),
         };
         h.rebuild(&settings.source);
         h
@@ -740,7 +874,7 @@ impl highlighter::Highlighter for SyntaxHighlighter {
         if ln < self.line_kinds.len()
             && matches!(self.line_kinds[ln], LineKind::Cordial | LineKind::Eval | LineKind::Comment)
         {
-            return highlight_cordial(line).into_iter();
+            return highlight_cordial(line, &self.user_idents).into_iter();
         }
 
         if ln >= self.line_offsets.len() {
@@ -775,6 +909,19 @@ impl highlighter::Highlighter for SyntaxHighlighter {
 
 pub fn highlight_color(kind: u8) -> Color {
     let p = palette::current();
+    if kind >= USER_IDENT_BASE && kind < USER_IDENT_BASE + USER_IDENT_PALETTE_SIZE {
+        return match kind - USER_IDENT_BASE {
+            0 => p.red,
+            1 => p.green,
+            2 => p.peach,
+            3 => p.blue,
+            4 => p.mauve,
+            5 => p.teal,
+            6 => p.yellow,
+            7 => p.pink,
+            _ => p.text,
+        };
+    }
     match kind {
         0  => p.mauve,
         1  => p.blue,