body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 0;
    background-color: #f4f7f9;
    color: #333;
}

.container {
    width: 95%; /* Mobile-first default */
    max-width: 1100px; /* Set a max-width for very large screens */
    margin: 40px auto;
    padding: 20px;
    background-color: #ffffff;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.05);
    box-sizing: border-box;
}

/* Media Query for PC screens */
@media (min-width: 768px) {
    .container {
        width: 60%;
    }
}

header {
    text-align: center;
    padding-bottom: 20px;
    border-bottom: 1px solid #eef2f5;
}

h1 {
    color: #1a2b48;
    font-size: 2.5em;
    margin-bottom: 0.2em;
}

.subtitle {
    font-size: 1.1em;
    color: #667;
}

main {
    padding: 20px 0;
}

h2 {
    color: #1a2b48;
    border-bottom: 2px solid #4a90e2;
    padding-bottom: 10px;
    margin-bottom: 20px;
}

.feature-item {
    margin-bottom: 20px;
}

.feature-item h3 {
    color: #333;
    font-size: 1.4em;
    margin-bottom: 5px;
}

.feature-item p {
    color: #555;
}

.call-to-action {
    text-align: center;
    padding: 30px;
    background-color: #f9fafb;
    border-radius: 5px;
    margin-top: 20px;
}

.call-to-action p {
    font-size: 1.2em;
    margin: 0;
}

.call-to-action strong {
    color: #4a90e2;
}

footer {
    text-align: center;
    margin-top: 30px;
    padding-top: 20px;
    border-top: 1px solid #eef2f5;
    font-size: 0.9em;
    color: #888;
}