body { font-family: 'Segoe UI', sans-serif; background: #f4f6f8; display: flex; justify-content: center; min-height: 100vh; margin: 0; align-items: center; }
.main-card { background: white; padding: 2rem; border-radius: 12px; box-shadow: 0 4px 20px rgba(0,0,0,0.08); width: 100%; max-width: 450px; text-align: center; }
.header img { margin-bottom: 1rem; }
.input-group { margin: 1.5rem 0; text-align: left; }
input { width: 100%; padding: 12px; border: 1px solid #ddd; border-radius: 8px; margin-top: 5px; box-sizing: border-box; }
button { width: 100%; padding: 12px; background: #0056b3; color: white; border: none; border-radius: 8px; cursor: pointer; font-weight: bold; font-size: 1rem; transition: background 0.3s; }
button:hover { background: #004494; }
button.secondary { background: #6c757d; margin-top: 1rem; }
.hidden { display: none; }
.spinner { border: 4px solid #f3f3f3; border-top: 4px solid #0056b3; border-radius: 50%; width: 30px; height: 30px; animation: spin 1s linear infinite; margin: 10px auto; }
.score-circle { font-size: 3rem; font-weight: bold; border: 5px solid #ddd; width: 100px; height: 100px; line-height: 90px; border-radius: 50%; margin: 0 auto 1rem; }
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }
details { text-align: left; background: #f8f9fa; padding: 10px; border-radius: 8px; margin-top: 15px; }