/* spinner z pracowni – zostawiam bo może się przydać */
.lds-roller {
    display: inline-block;
    position: relative;
    width: 80px;
    height: 80px;
}
.lds-roller div {
    animation: lds-roller 1.2s cubic-bezier(0.5, 0, 0.5, 1) infinite;
    transform-origin: 40px 40px;
}
.lds-roller div:after {
    content: " ";
    display: block;
    position: absolute;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: #0000ff;
    margin: -4px 0 0 -4px;
}
.lds-roller div:nth-child(1) { animation-delay: -0.036s; }
.lds-roller div:nth-child(1):after { top: 63px; left: 63px; }
.lds-roller div:nth-child(2) { animation-delay: -0.072s; }
.lds-roller div:nth-child(2):after { top: 68px; left: 56px; }
.lds-roller div:nth-child(3) { animation-delay: -0.108s; }
.lds-roller div:nth-child(3):after { top: 71px; left: 48px; }
.lds-roller div:nth-child(4) { animation-delay: -0.144s; }
.lds-roller div:nth-child(4):after { top: 72px; left: 40px; }
.lds-roller div:nth-child(5) { animation-delay: -0.18s; }
.lds-roller div:nth-child(5):after { top: 71px; left: 32px; }
.lds-roller div:nth-child(6) { animation-delay: -0.216s; }
.lds-roller div:nth-child(6):after { top: 68px; left: 24px; }
.lds-roller div:nth-child(7) { animation-delay: -0.252s; }
.lds-roller div:nth-child(7):after { top: 63px; left: 17px; }
.lds-roller div:nth-child(8) { animation-delay: -0.288s; }
.lds-roller div:nth-child(8):after { top: 56px; left: 12px; }
@keyframes lds-roller {
    0%   { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.err-field  { font-size: .85em; color: #dc3545; min-height: 1.1em; }
.is-invalid { border: 2px solid red !important; }
.is-valid   { border: 2px solid #198754 !important; }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }