body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #1a1a2e; /* Dark blue/purple for futuristic feel */
    color: #e0e0e0; /* Light grey text */
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

header {
    background-color: #0f0f1a; /* Even darker header */
    color: #e0e0e0;
    padding: 1rem 0;
    text-align: center;
    border-bottom: 2px solid #007bff; /* Blue accent */
}

header h1 {
    margin: 0;
    font-size: 2.5rem;
    color: #007bff;
}

header p {
    font-size: 1.1rem;
    margin-top: 0.5rem;
}

main {
    flex: 1;
    padding: 2rem;
    max-width: 900px;
    margin: 2rem auto;
    background-color: #2a2a4a; /* Slightly lighter dark background for content */
    border-radius: 10px;
    box-shadow: 0 0 20px rgba(0, 123, 255, 0.3); /* Blue glow effect */
}

section {
    margin-bottom: 2rem;
    padding: 1.5rem;
    border-radius: 8px;
    background-color: #3a3a5a; /* Even lighter background for sections */
}

h2 {
    color: #007bff;
    border-bottom: 1px solid #007bff;
    padding-bottom: 0.5rem;
    margin-top: 0;
    margin-bottom: 1.5rem;
}

.input-group {
    margin-bottom: 1.5rem;
}

.input-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #b0b0b0;
}

.input-group input[type="number"],
.input-group select,
.input-group input[type="range"] {
    width: calc(100% - 20px);
    padding: 10px;
    border: 1px solid #007bff;
    border-radius: 5px;
    background-color: #1a1a2e;
    color: #e0e0e0;
    font-size: 1rem;
    -webkit-appearance: none; /* Remove default styling for range input */
    appearance: none;
}

.input-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #007bff;
    cursor: pointer;
    margin-top: -5px; /* Center thumb vertically */
}

.input-group input[type="range"]::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: #007bff;
    cursor: pointer;
}

.input-group input[type="range"]::-webkit-slider-runnable-track {
    width: 100%;
    height: 10px;
    cursor: pointer;
    background: #555;
    border-radius: 5px;
}

.input-group input[type="range"]::-moz-range-track {
    width: 100%;
    height: 10px;
    cursor: pointer;
    background: #555;
    border-radius: 5px;
}

#wtpWtsValue {
    display: inline-block;
    margin-left: 10px;
    font-weight: bold;
    color: #007bff;
}

button {
    background-color: #007bff;
    color: white;
    padding: 12px 25px;
    border: none;
    border-radius: 5px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.2s ease;
    display: block;
    width: fit-content;
    margin: 1.5rem auto 0 auto;
}

button:hover {
    background-color: #0056b3;
    transform: translateY(-2px);
}

#patentValue {
    font-size: 1.8rem;
    font-weight: bold;
    text-align: center;
    margin-top: 1rem;
    color: #28a745; /* Green for positive value */
}

#chartContainer {
    margin-top: 2rem;
    height: 300px; /* Placeholder for chart */
    background-color: #1a1a2e;
    border-radius: 8px;
    display: flex;
    justify-content: center;
    align-items: center;
    color: #b0b0b0;
    font-style: italic;
    flex-direction: column;
}

#references ul {
    list-style: none;
    padding: 0;
}

#references li {
    margin-bottom: 0.8rem;
    padding-left: 1.5rem;
    position: relative;
}

#references li::before {
    content: '•';
    color: #007bff;
    position: absolute;
    left: 0;
}

#references a {
    color: #007bff;
    text-decoration: none;
}

#references a:hover {
    text-decoration: underline;
}

.reference {
    display: block;
    font-size: 0.85rem;
    color: #888;
    margin-top: 0.3rem;
}

footer {
    text-align: center;
    padding: 1.5rem 0;
    background-color: #0f0f1a;
    color: #b0b0b0;
    font-size: 0.9rem;
    border-top: 2px solid #007bff;
    margin-top: 2rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    main {
        margin: 1rem auto;
        padding: 1rem;
    }

    header h1 {
        font-size: 2rem;
    }

    header p {
        font-size: 1rem;
    }

    button {
        width: 100%;
    }
}