.progress-btn { position: relative; overflow: hidden; border: none; }
.progress-btn .progress-fill {
    position: absolute; top: 0; left: 0; bottom: 0;
    background: rgba(0, 0, 0, 0.15); width: 0%;
    transition: width 0.1s linear; z-index: 1;
}
body.dark-mode .progress-btn .progress-fill { background: rgba(255, 255, 255, 0.2); }
.progress-btn span { position: relative; z-index: 2; pointer-events: none; }

.upload-zone { border: 2px dashed var(--glass-border); transition: all 0.3s ease; }
.upload-zone:hover { border-color: #0071e3; background: rgba(0, 113, 227, 0.02); }

body.dark-mode #loadingOverlay { background: rgba(30, 30, 30, 0.85) !important; }

.canvas-container {
    position: relative; display: inline-block; width: 100%; max-width: 280px; 
    border-radius: 12px; overflow: hidden; border: 2px solid var(--glass-border); 
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}