body { font-family: sans-serif; line-height: 1.6; max-width: 800px; margin: 40px auto; padding: 20px; color: #333;
    background-image: linear-gradient(rgba(0,0,0,0.3), rgba(0,0,0,0.3)), url(背景たすかったじょーん.png); }
h1 { color: #2c3e50; border-bottom: 2px solid #2c3e50; }
h2 { color: #e67e22; margin-top: 30px; }
section { background: #f9f9f9; padding: 20px; border-radius: 8px; }