body {
    font-family: 'Roboto', sans-serif;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    background-color: #1a1a1a;
    color: #f2f2f2;
    padding: 2rem 0;
}

.main-container {
    display: flex;
    flex-direction: column;
    align-items: center;
    width: 100%;
    max-width: 1200px;
}

.roi-calculator-container, .documentation {
    display: flex;
    flex-direction: row;
    justify-content: space-around;
    align-items: flex-start;
    width: 100%;
}

.calculator,
.result-display, .how-it-works, .how-to-use {
    background-color: #2c2c2c;
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: 0 8px 16px rgba(0, 0, 0, 0.3);
    width: 45%;
    min-width: 350px;
    margin: 1rem;
}

@media (max-width: 768px) {
    .roi-calculator-container, .documentation {
        flex-direction: column;
        align-items: center;
    }

    .calculator,
    .result-display, .how-it-works, .how-to-use {
        width: 90%;
    }
}

h1, h2 {
    text-align: center;
    color: #00aaff;
}

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

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 500;
}

input {
    width: 100%;
    padding: 0.75rem;
    border: 1px solid #444;
    border-radius: 6px;
    background-color: #333;
    color: #f2f2f2;
    font-size: 1rem;
}

button {
    width: 100%;
    padding: 1rem;
    background-color: #007bff;
    color: #fff;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1.1rem;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #0056b3;
}

.result {
    margin-top: 2rem;
    text-align: left;
}

.result h2 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: #f2f2f2;
}

.result span {
    color: #00aaff;
    font-weight: 700;
}

.result p {
    font-style: italic;
    color: #aaa;
    text-align: center;
}

.documentation {
    margin-top: 2rem;
}

.documentation h2 {
    color: #00aaff;
    text-align: center;
    margin-bottom: 1.5rem;
}

.documentation p,
.documentation li {
    color: #f2f2f2;
    line-height: 1.6;
}

.documentation ul,
.documentation ol {
    padding-left: 20px;
}

.documentation ul {
    list-style-type: disc;
}

.documentation ol {
    list-style-type: decimal;
}

footer {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid #444;
    width: 100%;
}

footer p {
    margin: 0.5rem 0;
}

footer a {
    color: #00aaff;
    text-decoration: none;
}

footer a:hover {
    text-decoration: underline;
}