body { background: #111; color: white; font-family: sans-serif; margin: 0; padding: 0; } header { text-align: center; padding: 100px 20px; background: rgba(0,0,0,0.7); } section { padding: 40px 20px; } iframe { margin: 20px 0; } footer { text-align: center; padding: 20px; background: #000; }