html, body {
    margin: 0;
    padding: 0;
  }
  body {
    font-family: sans-serif;
    margin: 2rem;
    /* padding: 2rem; */
    border-radius: 8px;
    background-color: #fafafa; /* Light mode background */
  }
  label, button {
      display: block;
      margin: 0rem 0 0.5rem;
      width: 100%;
      box-sizing: border-box;
      text-align: left;
    }
    #timerContainer {
      display: flex;
      align-items: center;
      position: relative;
      width: fit-content;
      /* justify-content: center; */
      margin: 0 auto;
      /* width: 50%; */
      flex-direction: row;
    }
    #timer {
      text-align: center;
      margin-right: 8px;
      font-size: 1.5rem;
      margin-top: 1rem;
    }
    #blinkingDot.running-dot {
      width: 10px;
      height: 10px;
      background-color: red;
      border-radius: 50%;
      animation: blink 1s infinite alternate;
      /* margin-left: -8px; */
      position: absolute;
      right: -8px;
    }
    #confirm {
      margin-top: 1rem;
      color: green;
      display: none;
    }
    .main-container {
      max-width: 600px;
      margin: 0 auto;
      padding: 2rem;
      border-radius: 12px;
      border: 1px solid #ddd;
      background-color: #fff;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      text-align: center;
      position: relative;
    }
    .main-container button {
      margin: 16px auto 0;
      /* width: 50%; */
    }
    input, select, button {
      padding: 0.5rem 1rem;
      font-size: 1rem;
      width: 100%;
      box-sizing: border-box;
    }
  .start-button {
    background-color: green;
    color: white;
    border: none;
  }
  .stop-button {
    background-color: red;
    color: white;
    border: none;
  }
  .running-dot {
    margin-left: 8px;
    border-radius: 50%;
    width: 10px;
    height: 10px;
    background-color: red;
    display: inline-block;
    animation: blink 1s infinite alternate;
  }
  @keyframes blink {
    from { opacity: 1; }
    to { opacity: 0; }
  }
  #confirm.success-message {
    background-color: #D4EDDA;
    color: #155724;
    border: 1px solid #C3E6CB;
    display: inline-block;
    padding: 0.5rem 1rem;
    margin-top: 1rem;
    border-radius: 4px;
    animation: fadeInOut 2s forwards;
    position: absolute;
    display: flex;
    justify-content: center;
    width: 100%;
    box-sizing: border-box;
    margin: -2rem;
  }
  #confirm.error-message {
    background-color: #F8D7DA;
    color: #721C24;
    border: 1px solid #F5C6CB;
    display: inline-block;
    padding: 0.5rem 1rem;
    margin-top: 1rem;
    border-radius: 4px;
    animation: fadeInOut 2s forwards;
    position: absolute;
    display: flex;
    justify-content: center;
    width: 100%;
    box-sizing: border-box;
    margin: -2rem;
  }
  @keyframes fadeInOut {
    0% { opacity: 0; transform: translateY(10px); }
    10% { opacity: 1; transform: translateY(0); }
    90% { opacity: 1; transform: translateY(0); }
    100% { opacity: 0; transform: translateY(-10px); }
  }
  @media (prefers-color-scheme: dark) {
    body {
      background-color: #2f2f2f; /* Dark mode background */
      color: #f0f0f0;
    }
    .main-container {
      background-color: #3f3f3f;
      border: 1px solid #555;
    }
  }
  #debugUserId {
    position: absolute;
    bottom: -65px;
    right: 0;
    font-size: 18px;
    color: #999;
    opacity: 0.6;
    font-family: monospace;
    text-align: center;
    width: 100%;
  }