.form-step { display: none; }
.form-step.active { display: block; }
.spinner {
    display: none;
    border: 4px solid rgba(0, 0, 0, .1);
    width: 24px;
    height: 24px;
    border-radius: 50%;
    border-left-color: #09f;
    animation: spin 1s ease infinite;
}
@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}