html, body {
    height: 100%;
    margin: 0;
    display: flex;
    flex-direction: column;
}
.container{
    flex: 1;
}
h1{
    text-align: center;
}
nav {
    display: flex;
    justify-content: center;
    margin-bottom: 20px;
  }
  
  nav button {
    padding: 10px 20px;
    margin: 0 5px;
    border: none;
    background-color: #ddd;
    cursor: pointer;
    font-size: 16px;
    border-radius: 5px;
  }
  
  nav button.active {
    background-color: #4CAF50;
    color: white;
  }
    
  .section {
    display: none;
  }
  
  .section:not(.hidden) {
    display: block;
  }
  
  .hidden {
    display: none;
  }
  
  footer{
    text-align: center;
    margin-top: auto;
  }
  @media screen and (max-width: 400px){
    .container{
        margin: 0;
        width: 100vw;
        height: 100vh;
    }
    form{
        padding-left: 10px;
        width: 100%;
    }
    form .client-name{
        padding: 10px 0 10px 0;
    }
    form .client-name #client-name{
        width: 90%;
    }
    form textarea{
        width: 90%;
    }
    #generate-pdf-os{
        font-size: small;
        margin: 10px 0 10px 0;
        color: white;
        padding: 10px;
        border-radius: 5px;
        border: none;
        background-color: #4CAF50;
        width: 90%;
    }
    footer{
        margin-top: auto;
    }
  }