main {
    background-color: white;
    border-radius: 12px;
    padding: 20px 30px;
    max-width: 900px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    margin: 140px auto 40px auto;
}
h1 {
    font-size: 2.2em;
    text-align: center;
    color: #2c3e50;
    margin-bottom: 30px;
    border-bottom: 2px solid #e0e0e0;
    padding-bottom: 10px;
}
h2 {
    font-size: 1.8em;
    margin-bottom: 20px;
    text-align: center;
    color: #2c3e50;
}
section {
    margin-bottom: 40px;
}
p, li {
    line-height: 1.6;
    margin-bottom: 15px;
    color: #333;
}
ul {
    padding-left: 1.2em;
}
strong {
    color: #000;
}
@media (max-width: 768px) {
    main {
        margin: 120px 1rem 2rem 1rem;
        padding: 1.5rem;
    }
    h1 {
        font-size: 1.8em;
    }
    h2 {
        font-size: 1.5em;
    }
}
@media (max-width: 480px) {
    main {
        margin-top: 100px;
        padding: 1rem;
    }
    h1 {
        font-size: 1.5em;
    }
    h2 {
        font-size: 1.3em;
    }
    p, li {
        font-size: 0.95em;
    }
}