* {
        margin: 0;
        padding: 0;
        box-sizing: border-box;
      }

      body {
        font-family: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
        background: #f8f9fa;
        min-height: 100vh;
        display: flex;
        flex-direction: column;
        position: relative;
      }


      
      /* Signup Section */
      .signup-wrapper {
        flex: 1;
        display: flex;
        align-items: center;
        justify-content: center;
        padding: 2rem;
        position: relative;
        z-index: 5;
      }

      .signup-card {
        background: white;
        border-radius: 18px;
        padding: 3rem 2.5rem;
        width: 100%;
        max-width: 450px;
        box-shadow: 0 4px 20px rgba(63, 97, 190, 0.08);
        position: relative;
        margin-top: 80px;
      }



      .title {
        font-size: 2rem;
        font-weight: 700;
        color: #2d3748;
        margin-bottom: 0.5rem;
        text-align: center;
        letter-spacing: -0.5px;
      }

      .subtitle {
        color: #718096;
        text-align: center;
        margin-bottom: 2rem;
        font-size: 0.95rem;
      }

      form {
        display: flex;
        flex-direction: column;
        gap: 1.5rem;
      }

      .input-group {
        position: relative;
      }

      input {
        width: 100%;
        padding: 1rem 1.2rem;
        border: 1px solid #e2e8f0;
        border-radius: 6px;
        font-size: 1rem;
        transition: border-color 0.2s ease;
        background: white;
        color: #2d3748;
      }

      input:focus {
        outline: none;
        border-color: #1d4ed8;
      }

      input::placeholder {
        color: #a0aec0;
      }



      .options {
        display: flex;
        justify-content: center;
        margin-top: -0.5rem;
      }

      .options a {
        color: #0066cc;
        text-decoration: none;
        font-size: 0.9rem;
        font-weight: 500;
        transition: color 0.2s ease;
      }

      .options a:hover {
        color: #1d4ed8;
        text-decoration: underline;
      }

      .btn-primary {
        background: #0066cc;
        color: white;
        border: none;
        padding: 1rem;
        border-radius: 8px;
        font-size: 1rem;
        font-weight: 600;
        cursor: pointer;
        transition: all 0.2s ease;
        margin-top: 1rem;
      }

      .btn-primary:hover {
        background: #1d4ed8;
        box-shadow: 0 4px 12px rgba(49, 130, 206, 0.2);
      }

      .btn-primary:active {
        transform: translateY(1px);
      }

      .btn-primary:disabled {
        opacity: 0.6;
        cursor: not-allowed;
        transform: none;
      }

      .error-message {
        color: #e53e3e;
        font-size: 0.8rem;
        margin-top: 0.25rem;
        display: none;
      }

      .error-message.show {
        display: block;
      }

      /* Responsive */
      @media (max-width: 768px) {
        .hamburger {
          display: flex;
        }

        .nav-links {
          position: fixed;
          top: 80px;
          left: -100%;
          width: 100%;
          height: calc(100vh - 80px);
          background: white;
          box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
          flex-direction: column;
          justify-content: flex-start;
          align-items: center;
          padding-top: 2rem;
          transition: left 0.3s ease;
        }

        .nav-links.active {
          left: 0;
        }

        .nav-links a {
          padding: 1rem;
          font-size: 1.1rem;
        }

        .signup-card {
          padding: 2rem 1.5rem;
          margin: 1rem;
        }

        .title {
          font-size: 1.75rem;
        }
      }