body {
    font-family: 'Arial', sans-serif;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 100vh;
    transition: background-color 0.3s ease, color 0.3s ease;
    background: linear-gradient(135deg, #ffffff,#eaeaea, #d1d1d1,#bababa  );

  }
  

  header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
    padding: 20px;
    background: linear-gradient(135deg, #ffffff,#eaeaea, #d1d1d1,#bababa  );
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    position: fixed;
    top: 0;
    z-index: 1000;
  }
  
  header h1 {
    font-size: 1.5rem;
    color: #6a11cb;
    margin: 0;
  }
  
  header button {
    padding: 8px 16px;
    background: linear-gradient(135deg, #6a11cb, #2575fc);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
  }
  
  header button:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(106, 17, 203, 0.4);
  }
main {
    margin-top: 80px;
    padding: 20px;
    width: 90%;
    max-width: 800px;
  }
  
  .container {
    display: flex;
    background: rgba(255, 255, 255, 0.9);
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    animation: fadeIn 1s ease-in-out;
  }
  
  @keyframes fadeIn {
    from {
      opacity: 0;
      transform: translateY(-20px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
  
  .calculator, .result {
    flex: 1;
    padding: 30px;
  }
  
  .calculator {
    border-right: 1px solid #ddd;
  }
  
  .result {
    background: rgba(245, 245, 245, 0.9);
  }
  

  form label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
    color: #333;
  }
  
  form input, form button {
    width: 100%;
    padding: 10px;
    margin-bottom: 15px;
    border-radius: 8px;
    font-size: 1rem;
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
  }
  
  form input:focus {
    border-color: #6a11cb;
    outline: none;
    box-shadow: 0 0 8px rgba(106, 17, 203, 0.3);
  }
  
  form button {
    background: linear-gradient(135deg, #6a11cb, #2575fc);
    color: white;
    border: none;
    cursor: pointer;
  }
  
  form button:hover {
    transform: translateY(-3px);
    box-shadow: 0 5px 15px rgba(106, 17, 203, 0.4);
  }
  

  .result h2 {
    font-size: 1.5rem;
    color: #2575fc;
    margin-bottom: 20px;
  }
  
  .result-content p {
    font-size: 1.1rem;
  }
  
  #nextPeriod, #fertileWindow, #ovulationDate, #pregnancyTestDay, #dueDate {
    font-weight: bold;
    color: #6a11cb;
  }
  
  #healthTips {
    margin-top: 20px;
    padding: 20px;
    border-radius: 10px;
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
  }
  
  #healthTips h3 {
    margin-bottom: 15px;
    color: #6a11cb;
  }
  
  #healthTips ul {
    padding-left: 20px;
  }
  
  #healthTips li {
    margin-bottom: 10px;
  }
  

  body.dark-mode {
    background: linear-gradient(135deg, #000000,#252525, #444444,#747474  );
    color: #f0f0f0;
  }
  
  body.dark-mode header {
    background: rgba(27, 27, 36, 0.9);
  }
  
  body.dark-mode .container {
    background: rgba(27, 27, 36, 0.9);
  }
  
  body.dark-mode .result {
    background: rgba(27, 27, 36, 0.9);
  }
  
  body.dark-mode form input, body.dark-mode form select  {
    
    color: #000000;
    border-color: #ffffff;
  }

  body.dark-mode form label{
    color: white;
  }
  
  
  body.dark-mode #healthTips {
    background: rgba(60, 60, 80, 0.9);
  }
  

  @media (max-width: 768px) {
    .container {
      flex-direction: column;
    }
  
    .calculator {
      border-right: none;
      border-bottom: 1px solid #ddd;
    }
  }