* { margin: 0; padding: 0; box-sizing: border-box; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 20px;
    line-height: 1.8;
    color: #333;
    background: #fafafa;
}
h1 {
    text-align: center;
    font-size: 28px;
    color: #ff7a45;
    margin-bottom: 30px;
    padding-bottom: 15px;
    border-bottom: 2px solid #ff7a45;
}
h2 {
    font-size: 20px;
    color: #333;
    margin: 25px 0 15px;
    padding-left: 10px;
    border-left: 3px solid #ff7a45;
}
h3 {
    font-size: 16px;
    color: #555;
    margin: 20px 0 10px;
}
p { margin: 10px 0; text-align: justify; }
ul, ol { margin: 10px 0 10px 25px; }
li { margin: 5px 0; }
table { width: 100%; border-collapse: collapse; margin: 15px 0; }
th, td { border: 1px solid #ddd; padding: 10px 12px; text-align: left; }
th { background: #fff5f0; font-weight: 600; }
footer {
    margin-top: 40px; padding-top: 15px;
    border-top: 1px solid #eee;
    text-align: center; font-size: 12px; color: #999;
}
@media (max-width: 640px) {
    body { padding: 20px 15px; }
    h1 { font-size: 24px; }
    h2 { font-size: 18px; }
}