diff --git a/src/tui.zig b/src/tui.zig
index 5b2c93f..11aa0af 100644
--- a/src/tui.zig
+++ b/src/tui.zig
@@ -477,13 +477,17 @@ pub const App = struct {
         }
     }
 
+    /// Handles keypresses in symbol_input mode (activated by `/`).
+    /// Mini text input for typing a ticker symbol (e.g. AAPL, BRK.B, ^GSPC).
     fn handleInputKey(self: *App, ctx: *vaxis.vxfw.EventContext, key: vaxis.Key) void {
+        // Cancel input, return to normal mode
         if (key.codepoint == vaxis.Key.escape) {
             self.mode = .normal;
             self.input_len = 0;
             self.setStatus("Cancelled");
             return ctx.consumeAndRedraw();
         }
+        // Commit: uppercase the input, set as active symbol, switch to quote tab
         if (key.codepoint == vaxis.Key.enter) {
             if (self.input_len > 0) {
                 for (self.input_buf[0..self.input_len]) |*ch| ch.* = std.ascii.toUpper(ch.*);
@@ -499,17 +503,19 @@ pub const App = struct {
             self.input_len = 0;
             return ctx.consumeAndRedraw();
         }
+        // Delete last character
         if (key.codepoint == vaxis.Key.backspace) {
             if (self.input_len > 0) self.input_len -= 1;
             return ctx.consumeAndRedraw();
         }
+        // Ctrl+U: clear entire input (readline convention)
         if (key.matches('u', .{ .ctrl = true })) {
             self.input_len = 0;
             return ctx.consumeAndRedraw();
         }
-        if (key.codepoint >= 0x20 and key.codepoint < 0x7f and self.input_len < self.input_buf.len) {
-            const c: u8 = @intCast(key.codepoint);
-            self.input_buf[self.input_len] = std.ascii.toUpper(c);
+        // Accept printable ASCII (letters, digits, dots, hyphens, carets for tickers)
+        if (key.codepoint < std.math.maxInt(u7) and std.ascii.isPrint(@intCast(key.codepoint)) and self.input_len < self.input_buf.len) {
+            self.input_buf[self.input_len] = @intCast(key.codepoint);
             self.input_len += 1;
             return ctx.consumeAndRedraw();
         }