#resultContainer {
    position: relative;
    display: inline-block;
    line-height: 0;
}

#outputImage {
    display: block;
    max-width: 100%;
    height: auto;
    z-index: 1;
    border: 1px solid #000;
    box-sizing: border-box;
}

.line {
    position: absolute;
    z-index: 10;
    /* Symbol für Bewegung in alle Richtungen */
    cursor: move; 
    -webkit-appearance: none;
    appearance: none;
    background: red;
    height: 2px;
    margin: 0;
    padding: 0;
    outline: none;
    box-sizing: border-box;
}

.line:active {
    /* Zeigt während des Ziehens das "Gepackt"-Symbol */
    cursor: grabbing; 
}

.line.vertical {
    transform: rotate(90deg);
    transform-origin: 0 0;
}

/* --- Slider-Knopf (Thumb) --- */
.line::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    background: #333;
    border: 2px solid #fff;
    border-radius: 50%;
    /* Der Knopf selbst behält das Verschiebe-Symbol */
    cursor: move; 
}

.line::-moz-range-thumb {
    width: 16px;
    height: 16px;
    background: #333;
    border: 2px solid #fff;
    border-radius: 50%;
    cursor: move;
    border: none;
}

.line::-moz-range-track {
    background: transparent;
}