html, body {
    overflow: hidden;
    width: 100%;
    height: 100%;
    margin: 0;
    padding: 0;
}

#renderCanvas {
    width: 100%;
    height: 100%;
    touch-action: none;
}

.drop-zone {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.72);
    backdrop-filter: blur(6px);
    z-index: 10;
    cursor: pointer;
}

.drop-zone.hidden {
    display: none;
}

.drop-zone.dragover {
    background: rgba(207, 235, 255, 0.82);
}

.drop-zone.error {
    background: rgba(255, 232, 232, 0.82);
}

.drop-zone__panel {
    max-width: 32rem;
    margin: 1.5rem;
    padding: 1.5rem 1.75rem;
    border: 2px dashed #4d8dff;
    border-radius: 18px;
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 24px 60px rgba(40, 60, 90, 0.14);
    text-align: center;
}

.drop-zone.error .drop-zone__panel {
    border-color: #d64545;
}

.drop-zone__title {
    margin-bottom: 0.65rem;
    color: #16314f;
    font-size: 1.3rem;
    font-weight: 700;
}

.drop-zone__message {
    color: #42556d;
    font-size: 0.98rem;
    line-height: 1.5;
}