body {
    margin: 0;
    font: 16px sans-serif;
}

.container {
    position: relative;
    display: flex;
    flex-direction: column;
    max-width: 600px;
    min-height: 400px;
    margin: 20px auto auto;
    padding: 20px;
    border: 3px dashed #aaa;
    border-radius: 10px;
}

.container_drag {
    border-color: #444;
}

.label {
    position: absolute;
    display: flex;
    align-items: center;
    justify-content: center;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    font-size: 120%;
}

.buttons {
    display: flex;
    margin-top: auto;
}

.save {
    display: none;
    flex: 1 1 auto;
    margin-top: 10px;
    padding: 10px;
    background: #5ec25e;
    color: #fff;
    font-size: 120%;
    border: none;
    border-radius: 3px;
    cursor: pointer;
}

.save:first-child {
    margin-right: 10px;
}

.save:hover {
    background: #62cf62;
}

.container_with-data .label {
    display: none;
}

.container_with-data .save {
    display: block;
}