/* CSS Reset & PWA Essentials */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    touch-action: none; /* Critical: Disables native browser scrolling to allow Canvas touch events */
}

body {
    background-color: #0f172a; /* Sleek slate dark background */
    color: #f8fafc;
    overflow: hidden;
    position: fixed;
    width: 100vw;
    height: 100vh;
}

#ui-overlay {
    position: absolute;
    top: 30px;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 20px;
    z-index: 10;
    pointer-events: none; /* Let touches pass through the empty overlay space to canvas */
}

.logo {
    font-size: 1.4rem;
    font-weight: 800;
    letter-spacing: 1.5px;
    text-shadow: 0 4px 15px rgba(0,0,0,0.6);
}

.logo span {
    color: #38bdf8; /* Premium blue accent */
}

.upload-btn {
    pointer-events: auto; /* Re-enable clicks strictly on the button */
    background: rgba(255, 255, 255, 0.08); /* Glassmorphism background */
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(255, 255, 255, 0.15);
    padding: 14px 28px;
    border-radius: 40px;
    font-weight: 600;
    font-size: 1.05rem;
    cursor: pointer;
    box-shadow: 0 8px 25px rgba(0,0,0,0.4);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.upload-btn:active, .upload-btn:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(2px) scale(0.97);
}

#dxf-canvas {
    display: block;
    width: 100%;
    height: 100%;
    cursor: grab;
}

#dxf-canvas:active {
    cursor: grabbing;
}