body { font-family: sans-serif; background: #f8fafc; padding: 30px; }
.container { max-width: 900px; margin: 0 auto; background: white; padding: 30px; border-radius: 12px; border: 1px solid #cbd5e1; }
.back-link { text-decoration: none; color: #2563eb; font-weight: bold; margin-bottom: 20px; display: inline-block; }
.upload-box { margin: 20px 0; padding: 20px; border: 2px dashed #93c5fd; border-radius: 8px; text-align: center; }
.btn { background: #2563eb; color: white; border: none; padding: 10px 20px; border-radius: 6px; cursor: pointer; font-weight: bold; margin-top: 10px; }
.btn:disabled { background: #cbd5e1; }
.btn.download { background: #16a34a; margin-bottom: 15px; }
.preview-wrap { display: flex; gap: 15px; justify-content: center; flex-wrap: wrap; margin-top: 20px; }
canvas { border: 1px solid #ccc; border-radius: 6px; width: 320px; height: 200px; }