.drop-zone {
    border: 2px dashed #adb5bd;
    border-radius: .5rem;
    padding: 3rem 1rem;
    text-align: center;
    cursor: pointer;
    transition: border-color .15s ease-in-out, background-color .15s ease-in-out;
}

.drop-zone:hover,
.drop-zone.dragover,
.drop-zone:focus {
    border-color: #0d6efd;
    background-color: #e7f1ff;
    outline: none;
}

.drop-zone-icon {
    font-size: 2.5rem;
}

.progress-bar {
    transition: width .2s ease;
}