body {
    font-family: 'Inter', sans-serif;
}
/* Simple transition for smooth appearance */
.fade-in {
    animation: fadeIn 0.5s ease-in-out;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}
.copied-toast {
    animation: fadeInOut 2s ease-in-out;
}
@keyframes fadeInOut {
    0%, 100% { opacity: 0; transform: translateY(20px); }
    10%, 90% { opacity: 1; transform: translateY(0); }
}
#start-btn:disabled {
    cursor: not-allowed;
    opacity: 0.7;
}