* {
    font-family: 'Inter', sans-serif;
}

.loading-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.7);
    z-index: 9999;
    display: none;
    align-items: center;
    justify-content: center;
}

.loading-overlay.active {
    display: flex;
}

.spinner {
    border: 3px solid #f3f3f3;
    border-top: 3px solid #3b82f6;
    border-radius: 50%;
    width: 40px;
    height: 40px;
    animation: spin 1s linear infinite;
    margin: 0 auto;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.toast {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1000;
    animation: slideIn 0.3s ease;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

.sticky-timer {
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.95);
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.question-card {
    transition: all 0.3s ease;
    animation: fadeInUp 0.5s ease;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.option-btn {
    transition: all 0.2s ease;
    cursor: pointer;
}

.option-btn:hover {
    transform: translateX(5px);
    background-color: #f3f4f6;
}

.option-btn.selected {
    background-color: #dbeafe;
    border-color: #3b82f6;
    border-width: 2px;
}

.timer-warning {
    animation: pulse 1s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.7; }
}

::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: #888;
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: #555;
}