* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Segoe UI', sans-serif; background: #ecf0f1; display: flex; justify-content: center; padding-top: 50px; min-height: 100vh; }
.container { background: white; padding: 30px; border-radius: 10px; width: 600px; box-shadow: 0 4px 15px rgba(0,0,0,0.1); }
h1 { text-align: center; margin-bottom: 30px; color: #2c3e50; }
.box { padding: 40px; border-radius: 8px; text-align: center; font-weight: bold; margin-bottom: 20px; transition: 0.3s; cursor: pointer; }
.outer { background: #3498db; color: white; }
.inner { background: #e74c3c; margin-top: 20px; }
#btn { padding: 10px 20px; background: #f1c40f; border: none; border-radius: 5px; font-weight: bold; cursor: pointer; margin-top: 20px; }
#btn:hover { background: #f39c12; }
.controls { margin-bottom: 20px; display: flex; justify-content: space-between; align-items: center; }
#clearBtn { padding: 8px 15px; background: #7f8c8d; color: white; border: none; border-radius: 5px; cursor: pointer; }
h2 { margin-bottom: 10px; font-size: 18px; color: #333; }
.log { list-style: none; background: #f8f9fa; padding: 15px; border-radius: 5px; border: 1px solid #ddd; max-height: 200px; overflow-y: auto; }
.log li { padding: 5px; border-bottom: 1px solid #eee; font-family: monospace; }