body { 
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; 
    background: #f9fafb; 
    margin: 0; 
    display: flex; 
    justify-content: center; 
    user-select: none;
}
.app-container { width: 100%; max-width: 450px; padding: 20px; min-height: 100vh; background: white; }
.header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 20px; }
h3 { margin: 0; font-size: 1.1rem; color: #1f2937; }
h3 span { color: #6b7280; font-weight: normal; }
.progress-info { text-align: right; width: 50%; }
.progress-bar-bg { background: #e5e7eb; height: 10px; border-radius: 10px; margin-bottom: 5px; overflow: hidden; }
#progress-fill { background: #2563eb; width: 0%; height: 100%; transition: 0.4s ease; }
#question-text { font-size: 1.2rem; color: #111827; margin-top: 30px; margin-bottom: 20px; }
.option { border: 2px solid #f3f4f6; border-radius: 15px; padding: 16px; margin-bottom: 12px; cursor: pointer; transition: 0.2s; font-size: 1rem; color: #374151; }
.option:active { transform: scale(0.98); }
.correct-opt { border-color: #10b981 !important; background: #ecfdf5 !important; color: #065f46; font-weight: bold; }
.wrong-opt { border-color: #ef4444 !important; background: #fef2f2 !important; color: #991b1b; }
#feedback-box { position: fixed; bottom: 0; left: 0; right: 0; padding: 25px; border-radius: 25px 25px 0 0; box-shadow: 0 -10px 20px rgba(0,0,0,0.1); z-index: 100; }
.hidden { display: none; }
#next-btn { background: #10b981; color: white; border: none; padding: 15px; width: 100%; border-radius: 12px; font-size: 1.1rem; font-weight: bold; cursor: pointer; margin-top: 15px; }