.stats.best.textContent = String(state.bestStreak);
        els.stats.skips.textContent = String(state.skips);
      }

      function updateHighUI() {
        els.stats.high.textContent = String(getHighScoreForCurrentMode());
      }

      function problemToFocus() {
        requestAnimationFrame(() => {
          els.answer.focus();
          els.answer.select();
        });
      }

      function start() {
        if (state.running) return;
        summarizeMode();
        state = defaultState();
     