diff --git a/src/ansi.ts b/src/ansi.ts
index 56b4b86..6ee2b3d 100644
--- a/src/ansi.ts
+++ b/src/ansi.ts
@@ -55,40 +55,17 @@ interface ExtendedColorResult {
 
 // Trim trailing whitespace from each line to prevent background color bleeding.
 // Terminal buffers often pad lines with spaces. Preserve trailing ANSI resets.
-// ESC character code
-const ESC = "\x1b";
-
 export function trimLineEndPreserveAnsi(line: string): string {
-  // Peel off any ANSI sequences at the end of the line
   let end = line.length;
   let ansiSuffix = "";
   while (end > 0) {
-    // Check for ANSI escape sequence at end: ESC [ params letter
-    const suffix = line.slice(0, end);
-    if (!suffix.endsWith("]")) {
-      // Look for the closing letter (A-Z, a-z)
-      const lastChar = suffix[suffix.length - 1];
-      if (!lastChar || !/[A-Za-z]/.test(lastChar)) break;
-
-      // Walk back to find ESC [
-      let seqStart = suffix.length - 2;
-      while (seqStart >= 0 && /[0-9;?]/.test(suffix[seqStart] || "")) {
-        seqStart--;
-      }
-      if (seqStart < 0 || suffix[seqStart] !== "[") break;
-      seqStart--;
-      if (seqStart < 0 || suffix[seqStart] !== ESC) break;
-
-      // Found a valid ANSI sequence
-      const seq = suffix.slice(seqStart);
-      ansiSuffix = seq + ansiSuffix;
-      end = seqStart;
-    } else {
-      break;
-    }
+    // biome-ignore lint/suspicious/noControlCharactersInRegex: ESC character is intentional for ANSI sequences
+    const match = line.slice(0, end).match(/\u001b\[[0-9;?]*[A-Za-z]$/);
+    if (!match) break;
+    ansiSuffix = match[0] + ansiSuffix;
+    end -= match[0].length;
   }
-  const trimmed = line.slice(0, end).trimEnd();
-  return trimmed + ansiSuffix;
+  return line.slice(0, end).trimEnd() + ansiSuffix;
 }
 
 // Parse extended color: 38;2;R;G;B (24-bit) or 38;5;N (256-color)