body { font-family: "Helvetica", sans-serif; line-height: 1.8; background-color: #ffffff; padding: 2em; color: #333; } h1 { color: #2e7d32; /* 緑 */ border-bottom: 2px solid #a5d6a7; } h2 { color: #1976d2; /* 青 */ border-left: 4px solid #64b5f6; padding-left: 8px; margin-top: 2em; } h3 { color: #d32f…