/* 优化后的CSS */
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
        sans-serif;
    line-height: 1.6;
    margin: 0;
    padding: 20px;
    max-width: 800px;
    margin: 0 auto;
    color: #333;
}
.model-section {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 30px;
}
h1 {
    color: #1d1d1f;
    font-size: 2.4em;
    margin-bottom: 30px;
}
h2 {
    color: #1d1d1f;
    font-size: 1.8em;
    margin: 25px 0;
}
.step-list {
    list-style: none;
    padding-left: 0;
}
.step-item {
    margin-bottom: 20px;
    padding-left: 35px;
    position: relative;
}
.step-item::before {
    content: "✓";
    color: #007aff;
    position: absolute;
    left: 0;
    font-size: 1.2em;
}
.device-image {
    width: 100%;
    max-width: 400px;
    height: auto;
    margin: 15px 0;
    border-radius: 8px;
}
@media (max-width: 768px) {
    h1 {
        font-size: 2em;
    }
    h2 {
        font-size: 1.5em;
    }
}