:root {
    --kakao-black: #000000;
    --kakao-yellow: #fee500;
    --kakao-gray: #f6f6f6;
    --kakao-dark-gray: #666666;
    --kakao-blue: #4c4c4c;
  }
  
  body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #ffffff;
    color: var(--kakao-black);
    min-height: 100vh;
    overflow-x: hidden;
  }
  
  .header {
    background-color: var(--kakao-black);
    color: white;
    padding: 0.5rem 0;
    margin-bottom: 1rem;
  }
  
  .header h1 {
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
    font-size: 1.2rem;
    font-weight: 600;
  }
  
  .main-container {
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
    padding: 0 1rem;
    box-sizing: border-box;
  }
  
  .container {
    background-color: var(--kakao-gray);
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  }
  
  .notice {
    background-color: #ffffff;
    padding: 0.8rem;
    border-radius: 8px;
    margin-bottom: 1rem;
    border: 1px solid #e5e5e5;
  }
  
  .notice h3 {
    color: var(--kakao-black);
    margin: 0 0 0.5rem 0;
    font-size: 1rem;
    font-weight: 600;
  }
  
  .notice pre {
    color: var(--kakao-dark-gray);
    margin: 0;
    font-size: 0.8rem;
    line-height: 1.4;
    white-space: pre-wrap;
    word-wrap: break-word;
  }
  
  button {
    background-color: var(--kakao-yellow);
    border: none;
    padding: 8px 16px;
    margin: 3px;
    border-radius: 4px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.9rem;
    color: var(--kakao-black);
    transition: background-color 0.2s;
    white-space: nowrap;
  }
  
  button:hover {
    background-color: #ffde00;
  }
  
  input {
    background-color: white;
    border: 1px solid #e5e5e5;
    border-radius: 4px;
    padding: 8px 12px;
    font-size: 0.9rem;
    width: 100%;
    max-width: 300px;
    margin: 3px;
    box-sizing: border-box;
  }
  
  input::placeholder {
    color: #999;
    font-size: 0.8rem;
  }
  
  .friend-message-container {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 0.5rem 0;
    flex-wrap: wrap;
  }
  
  textarea {
    width: 100%;
    margin-top: 10px;
    border-radius: 4px;
    padding: 10px;
    border: 1px solid #e5e5e5;
    font-family: monospace;
    font-size: 12px;
    line-height: 1.4;
    resize: none;
    height: 150px;
    box-sizing: border-box;
  }
  
  .section-title {
    color: var(--kakao-black);
    font-size: 1rem;
    font-weight: 600;
    margin: 1rem 0 0.5rem;
  }
  
  .button-group {
    margin: 0.5rem 0;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
    align-items: center;
  }
  
  .login-container {
    text-align: center;
    margin: 1rem 0;
  }
  
  .login-container img {
    width: 180px;
    max-width: 100%;
    height: auto;
  }
  
  .api-container {
    background-color: white;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 0.5rem;
    border: 1px solid #e5e5e5;
    width: 100%;
    box-sizing: border-box;
  }
  
  .vertical-layout {
    display: flex;
    flex-direction: column;
    gap: 1rem;
  }
  
  .login-buttons {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
  }
  
  .kakao-js-login {
    background-color: var(--kakao-yellow);
    border: none;
    padding: 12px 24px;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
    font-size: 1rem;
    color: var(--kakao-black);
    transition: background-color 0.2s;
  }
  
  .kakao-js-login:hover {
    background-color: #ffde00;
  }
  
  @media (max-width: 600px) {
    .header h1 {
      font-size: 1rem;
      text-align: center;
    }
  
    .main-container {
      padding: 0 0.5rem;
    }
  
    .container {
      padding: 0.5rem;
    }
  
    .notice {
      padding: 0.5rem;
    }
  
    .button-group {
      justify-content: center;
    }
  
    .friend-message-container {
      flex-direction: column;
      align-items: stretch;
    }
  
    input {
      max-width: 100%;
    }
  
    .login-buttons {
      flex-direction: column;
      gap: 0.5rem;
    }
  
    .kakao-js-login {
      width: 100%;
      max-width: 300px;
    }
  }