body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 20px;
    background-color: #f0f4f8; /* Light grayish blue */
    color: #333;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
}

.container {
    background-color: #ffffff;
    padding: 25px 30px;
    border-radius: 10px;
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.08);
    width: 100%;
    max-width: 650px; /* Slightly wider for comfort */
}

h1 {
    color: #1a2533; /* Darker blue */
    text-align: center;
    margin-bottom: 30px;
    font-weight: 600;
}

.form-group {
    margin-bottom: 22px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500; /* Medium weight */
    color: #4a5568; /* Slate gray */
}

.form-group input[type="number"],
.form-group select {
    width: 100%;
    padding: 12px 15px;
    border: 1px solid #cbd5e0; /* Lighter gray border */
    border-radius: 6px;
    box-sizing: border-box;
    font-size: 1rem;
    transition: border-color 0.2s ease-in-out, box-shadow 0.2s ease-in-out;
}

.form-group input[type="number"]:focus,
.form-group select:focus {
    outline: none;
    border-color: #4299e1; /* Blue focus */
    box-shadow: 0 0 0 3px rgba(66, 153, 225, 0.2);
}

button {
    display: block;
    width: 100%;
    padding: 12px 15px;
    background-color: #3182ce; /* Primary blue */
    color: white;
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.2s ease;
    margin-top: 15px; /* Space from last form group */
}

button:hover {
    background-color: #2b6cb0; /* Darker blue on hover */
}

.results-area {
    margin-top: 35px;
    padding: 20px 25px;
    background-color: #f7fafc; /* Very light blue/gray */
    border-radius: 8px;
    border: 1px solid #e2e8f0; /* Light border */
}

.results-area h2, .results-area h3 {
    color: #1a2533;
    margin-top: 0;
}

.results-area h2 {
    margin-bottom: 15px;
    font-size: 1.5em;
}

.results-area h3 {
    margin-top: 25px;
    margin-bottom: 12px;
    font-size: 1.2em;
    border-bottom: 1px solid #e2e8f0;
    padding-bottom: 8px;
    font-weight: 500;
}

.results-area p {
    margin-bottom: 12px;
    font-size: 1rem;
    color: #2d3748; /* Dark gray for text */
}

.export-buttons {
    margin-top: 25px;
    display: flex;
    gap: 15px; /* Space between buttons */
}

.export-buttons button {
    flex: 1; /* Make buttons take equal width */
}

#exportPdfButton {
    background-color: #dd6b20; /* Orange */
}
#exportPdfButton:hover {
    background-color: #c05621; /* Darker orange */
}

#exportExcelButton {
    background-color: #38a169; /* Green */
}
#exportExcelButton:hover {
    background-color: #2f855a; /* Darker green */
}

.error-messages {
    color: #c53030; /* Red */
    font-weight: 500;
    margin-top: 20px;
    padding: 12px 15px;
    background-color: #fed7d7; /* Light red background */
    border: 1px solid #f56565; /* Red border */
    border-radius: 6px;
}

/* Responsive adjustments */
@media (max-width: 680px) {
    body {
        padding: 15px;
    }
    .container {
        padding: 20px;
    }
    .export-buttons {
        flex-direction: column;
    }
    button {
        font-size: 1rem;
    }
     h1 {
        font-size: 1.8rem;
    }
}