:root{
  --primary:#4f46e5;
  --primary-dark:#4338ca;
  --bg:#f4f5fa;
  --card:#ffffff;
  --border:#e2e4ee;
  --text:#1f2233;
  --muted:#6b7085;
  --danger:#dc2626;
  --success:#16a34a;
  --radius:14px;
}

*{box-sizing:border-box;}

body{
  margin:0;
  font-family:'Segoe UI', Roboto, Arial, sans-serif;
  background:var(--bg);
  color:var(--text);
  min-height:100vh;
  display:flex;
  align-items:flex-start;
  justify-content:center;
  padding:40px 16px;
}

.wrapper{
  width:100%;
  max-width:640px;
}

header{
  text-align:center;
  margin-bottom:24px;
  position:relative;
}

.back-link{
  display:inline-block;
  margin-bottom:14px;
  color:var(--muted);
  font-size:13px;
  text-decoration:none;
  font-weight:600;
}

.back-link:hover{
  color:var(--primary);
}

header h1{
  margin:0 0 6px;
  font-size:28px;
}

header p{
  margin:0;
  color:var(--muted);
  font-size:14px;
}

.card{
  background:var(--card);
  border:1px solid var(--border);
  border-radius:var(--radius);
  padding:24px;
  box-shadow:0 4px 18px rgba(20,20,50,0.06);
}

.dropzone{
  border:2px dashed #c6c9dd;
  border-radius:var(--radius);
  padding:36px 16px;
  text-align:center;
  cursor:pointer;
  transition:border-color .15s, background .15s;
}

.dropzone.dragover{
  border-color:var(--primary);
  background:#f1f0ff;
}

.dropzone-content{
  display:flex;
  flex-direction:column;
  align-items:center;
  gap:4px;
  color:var(--muted);
}

.dropzone-content .icon{
  font-size:30px;
  margin-bottom:6px;
}

.dropzone-content strong{
  color:var(--text);
  font-size:16px;
}

.file-list{
  list-style:none;
  margin:18px 0 0;
  padding:0;
  display:flex;
  flex-direction:column;
  gap:8px;
}

.file-item{
  display:flex;
  align-items:center;
  gap:10px;
  background:#f8f8fc;
  border:1px solid var(--border);
  border-radius:10px;
  padding:10px 12px;
  cursor:grab;
}

.file-item.dragging{
  opacity:0.4;
}

.file-item .handle{
  color:#a7abc2;
  font-size:16px;
  user-select:none;
}

.file-item .order{
  width:22px;
  height:22px;
  border-radius:50%;
  background:var(--primary);
  color:#fff;
  font-size:12px;
  font-weight:600;
  display:flex;
  align-items:center;
  justify-content:center;
  flex-shrink:0;
}

.file-item .name{
  flex:1;
  font-size:14px;
  overflow:hidden;
  text-overflow:ellipsis;
  white-space:nowrap;
}

.file-item .size{
  font-size:12px;
  color:var(--muted);
  flex-shrink:0;
}

.file-item .remove{
  border:none;
  background:transparent;
  color:var(--danger);
  cursor:pointer;
  font-size:16px;
  line-height:1;
  padding:2px 4px;
}

.hint{
  font-size:12px;
  color:var(--muted);
  margin:10px 2px 0;
}

.actions{
  display:flex;
  gap:10px;
  margin-top:20px;
}

.btn{
  border:none;
  border-radius:10px;
  padding:12px 18px;
  font-size:14px;
  font-weight:600;
  cursor:pointer;
  text-decoration:none;
  text-align:center;
  display:inline-block;
}

.btn-primary{
  background:var(--primary);
  color:#fff;
  flex:1;
}

.btn-primary:hover{
  background:var(--primary-dark);
}

.btn-primary:disabled{
  background:#b7b9d6;
  cursor:not-allowed;
}

.btn-secondary{
  background:#eceefa;
  color:var(--text);
}

.btn-secondary:hover{
  background:#dfe1f4;
}

.progress-wrap{
  margin-top:18px;
}

.progress-bar{
  width:100%;
  height:8px;
  background:#eceefa;
  border-radius:99px;
  overflow:hidden;
}

.progress-fill{
  height:100%;
  width:0%;
  background:var(--primary);
  transition:width .15s ease;
}

#progressText{
  display:block;
  margin-top:6px;
  font-size:12px;
  color:var(--muted);
}

.result-box{
  margin-top:20px;
  text-align:center;
  background:#f0fdf4;
  border:1px solid #bbf7d0;
  border-radius:var(--radius);
  padding:20px;
}

.result-box .icon{
  font-size:26px;
}

.result-box p{
  margin:6px 0 14px;
  color:var(--success);
  font-weight:600;
}

.error-box{
  margin-top:18px;
  background:#fef2f2;
  border:1px solid #fecaca;
  color:var(--danger);
  border-radius:10px;
  padding:12px 14px;
  font-size:14px;
}

footer{
  text-align:center;
  margin-top:16px;
}

footer small{
  color:var(--muted);
}