All code snippets, hints, seed code, and automated checks must follow a single, consistent formatting and style contract—especially around quote usage and basic JS/TS syntax.

Apply these rules:

• Formatting: use the team’s standard indentation (e.g., 2 spaces) and include semicolons consistently.
• No broken snippets: seed code examples must compile/parse; avoid syntax errors and duplicate declarations.
• Quote-robust tests/hints: when matching user code, support both single and double quotes and (when relevant) ensure the same quote type is used via backreferences.
• Pattern consistency: hints should prefer the same DOM/API patterns the seed uses (to avoid ambiguity), unless there’s an explicit reason to allow alternatives.

Example (quote-robust hint regex):

// Matches: document.getElementById('income') or document.getElementById("income")
assert.match(code, /document\.getElementById\(\s*(['"])income\1\s*\)/);

Example (style-correct TS):

function f(): void {
  const x = 1;
  console.log(x);
}

Example (avoid duplicate seed declarations):

const cardDisplay = document.querySelector<HTMLElement>("#current-card")!; 
// (don’t redeclare cardDisplay again)