A student injects a sample of colorless \(\text{N}_2\text{O}_4\text{(g)}\) into an evacuated, sealed rigid container at a constant temperature. Over time, brown \(\text{NO}_2\text{(g)}\) forms according to the reaction \(\text{N}_2\text{O}_4\text{(g)} \rightleftharpoons 2\text{NO}_2\text{(g)}\). After several minutes, the intensity of the brown color inside the container remains constant. Which of the following best describes the state of the system after the brown color stops changing, and provides the correct justification?