form {
    margin: 50px auto;
    padding: 20px;
    width: 600px;
    border: 1px solid black;
}

.drop-area {
    position: relative;
    width: 100%;
    min-height: 100px;
    background: gray;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    flex-direction: column;
    cursor: pointer;
}

.drop-area .error {
    color: #c50000;
}

.drop-area .error p {
    margin: 0 0 10px 0;
}

.drop-area.highlight {
    opacity: 0.5;
}

.drop-area .invis {
    display: none;
}

.delete {
    position: absolute;
    top: 0;
    right: 0;
    background: #0397ca;
    padding: 10px;
    cursor: pointer;
    z-index: 1;
    transition: background-color 0.3s;
}

.delete:hover {
    background: #c50000;
}

.overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.5);
    opacity: 0;
}

.dropped-files {
    width: 100%;
}

.dropped-files .file {
    width: calc(100% - 40px);
    border: 1px solid black;
    padding: 10px;
    margin: 10px;
    position: relative;
    background-color: #FFFFFF;
}