.bwt-container {
    font-family: Arial, sans-serif;
    margin: 2em;
    background-color: #f9f9f9;
}
.bwt-container h1 {
    text-align: center;
}
.bwt-container form {
    max-width: 500px;
    margin: 0 auto 2em auto;
    padding: 1em;
    background: #fff;
    border-radius: 5px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}
.bwt-container form label {
    display: block;
    margin-top: 1em;
}
.bwt-container form input,
.bwt-container form select {
    width: 100%;
    padding: 0.5em;
    margin-top: 0.5em;
}
.bwt-container form button {
    margin-top: 1.5em;
    padding: 0.7em;
    width: 100%;
    background: #0073aa;
    border: none;
    color: #fff;
    font-size: 1em;
    border-radius: 3px;
    cursor: pointer;
}
.bwt-container form button:hover {
    background: #005f8d;
}
.chart-container {
    max-width: 800px;
    margin: 2em auto;
    background: #fff;
    padding: 1em;
    border-radius: 5px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}