#excel-splitter-app *{box-sizing:border-box}#excel-splitter-app{font-family:Inter,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif;background:linear-gradient(135deg,#667eea,#764ba2);min-height:100vh;padding:2rem;color:#333}#excel-splitter-app .container{max-width:800px;margin:0 auto}#excel-splitter-app .header{text-align:center;margin-bottom:3rem;animation:fadeInDown .6s ease-out}#excel-splitter-app .header h1{color:#fff;font-size:2.5rem;font-weight:700;margin-bottom:.5rem;text-shadow:0 2px 10px rgba(0,0,0,.2)}#excel-splitter-app .header p{color:#ffffffe6;font-size:1.1rem}#excel-splitter-app .card{background:#fffffff2;backdrop-filter:blur(10px);border-radius:20px;padding:2.5rem;box-shadow:0 20px 60px #0000004d;margin-bottom:2rem;animation:fadeInUp .6s ease-out}.upload-area{border:3px dashed #667eea;border-radius:15px;padding:3rem 2rem;text-align:center;cursor:pointer;transition:all .3s ease;background:linear-gradient(135deg,#f5f7fa,#c3cfe2);position:relative;overflow:hidden}.upload-area:before{content:"";position:absolute;top:0;left:-100%;width:100%;height:100%;background:linear-gradient(90deg,transparent,rgba(255,255,255,.4),transparent);transition:left .5s}.upload-area:hover:before{left:100%}.upload-area:hover{border-color:#764ba2;transform:translateY(-5px);box-shadow:0 10px 30px #667eea4d}.upload-area.dragover{border-color:#764ba2;background:linear-gradient(135deg,#e0c3fc,#8ec5fc);transform:scale(1.02)}.upload-icon{font-size:4rem;margin-bottom:1rem;display:inline-block;animation:bounce 2s infinite}.upload-text{font-size:1.2rem;color:#667eea;font-weight:600;margin-bottom:.5rem}.upload-hint{color:#666;font-size:.9rem}input[type=file]{display:none}.section{margin-top:2rem;animation:fadeIn .5s ease-out}.section-title{font-size:1.3rem;font-weight:600;margin-bottom:1rem;color:#667eea;display:flex;align-items:center;gap:.5rem}#excel-splitter-app .columns-grid{display:grid!important;grid-template-columns:repeat(auto-fill,minmax(200px,1fr))!important;gap:.75rem!important;margin-bottom:1.5rem!important}#excel-splitter-app .column-item{padding:1rem!important;background:linear-gradient(135deg,#f5f7fa,#e9ecef)!important;border:2px solid #ddd!important;border-radius:10px!important;cursor:pointer!important;transition:all .3s ease!important;text-align:center!important;font-weight:500!important;user-select:none!important;position:relative!important;display:block!important}#excel-splitter-app .column-item:hover{transform:translateY(-3px)!important;box-shadow:0 5px 15px #667eea33!important;border-color:#667eea!important;background:linear-gradient(135deg,#e8eaef,#d9dde6)!important}#excel-splitter-app .column-item.selected{background:linear-gradient(135deg,#667eea,#764ba2)!important;color:#fff!important;border-color:#764ba2!important;box-shadow:0 5px 20px #667eea66!important;transform:translateY(-3px)!important}#excel-splitter-app .column-item.selected:after{content:"✓";position:absolute;top:5px;right:8px;font-size:1.2rem;font-weight:700}.options-group{margin-bottom:1.5rem}.checkbox-wrapper{display:flex;align-items:center;gap:.75rem;padding:1rem;background:#f8f9fa;border-radius:10px;cursor:pointer;transition:all .3s ease}.checkbox-wrapper:hover{background:#e9ecef}.checkbox-wrapper input[type=checkbox]{width:24px;height:24px;cursor:pointer;accent-color:#667eea}.checkbox-label{font-weight:500;color:#333;flex:1}.checkbox-description{font-size:.85rem;color:#666;margin-top:.25rem}.btn{padding:1rem 2.5rem;border:none;border-radius:50px;font-size:1.1rem;font-weight:600;cursor:pointer;transition:all .3s ease;display:inline-flex;align-items:center;gap:.5rem;text-decoration:none;font-family:inherit}.btn-primary{background:linear-gradient(135deg,#667eea,#764ba2);color:#fff;box-shadow:0 5px 20px #667eea66}.btn-primary:hover:not(:disabled){transform:translateY(-3px);box-shadow:0 8px 30px #667eea99}.btn-primary:disabled{opacity:.6;cursor:not-allowed}.btn-secondary{background:#6c757d;color:#fff}.btn-secondary:hover{background:#5a6268;transform:translateY(-2px)}.btn-group{display:flex;gap:1rem;justify-content:center;flex-wrap:wrap}.progress-section{margin-top:1.5rem;display:none}.progress-section.active{display:block}.progress-bar{width:100%;height:8px;background:#e9ecef;border-radius:10px;overflow:hidden;margin-bottom:1rem}.progress-fill{height:100%;background:linear-gradient(90deg,#667eea,#764ba2);width:0%;transition:width .3s ease;animation:shimmer 2s infinite}.status-message{padding:1rem;border-radius:10px;margin-bottom:1rem;display:none;animation:slideIn .3s ease-out}.status-message.active{display:block}.status-message.success{background:#d4edda;color:#155724;border:1px solid #c3e6cb}.status-message.error{background:#f8d7da;color:#721c24;border:1px solid #f5c6cb}.status-message.info{background:#d1ecf1;color:#0c5460;border:1px solid #bee5eb}.file-info{display:flex;align-items:center;gap:1rem;padding:1rem;background:linear-gradient(135deg,#e0c3fc,#8ec5fc);border-radius:10px;margin-bottom:1rem}.file-icon{font-size:2rem}.file-details{flex:1}.file-name{font-weight:600;color:#333;margin-bottom:.25rem}.file-size{font-size:.85rem;color:#666}@keyframes fadeInDown{0%{opacity:0;transform:translateY(-20px)}to{opacity:1;transform:translateY(0)}}@keyframes fadeInUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes bounce{0%,to{transform:translateY(0)}50%{transform:translateY(-10px)}}@keyframes shimmer{0%{background-position:-1000px 0}to{background-position:1000px 0}}@keyframes slideIn{0%{transform:translate(-20px);opacity:0}to{transform:translate(0);opacity:1}}@media(max-width:768px){body{padding:1rem}.header h1{font-size:2rem}.card{padding:1.5rem}.columns-grid{grid-template-columns:1fr}.btn-group{flex-direction:column}.btn{width:100%;justify-content:center}}