body {
  background-color: #f8f9fa;
  font-family: 'Arial', sans-serif;
}
.container {
  max-width: 600px;
  margin-top: 5%;
  text-align: center;
  background: #fff;
  padding: 40px 30px;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
h1 {
  font-size: 1.8rem;
  font-weight: 600;
  margin-bottom: 20px;
}
.btn-primary {
  border: none;
  padding: 10px 20px;
  font-size: 1rem;
  border-radius: 5px;
}
footer {
  text-align: center;
  margin-top: 40px;
  color: #6c757d;
  font-size: 0.9rem;
}
.loading {
  display: none;
  margin-top: 15px;
  color: #007bff;
  font-weight: 500;
}
.file-name {
  margin-top: 10px;
  word-break: break-all;
}
.drop-zone {
  border: 2px dashed #cbd5e1;
  background: #f9fafb;
  padding: 40px 20px;
  border-radius: 10px;
  cursor: pointer;
  transition: all .15s ease-in-out;
}
.drop-zone:hover {
  background: #f1f5f9;
}
.drop-zone.dragover {
  border-color: #0d6efd;
  background: #e9f2ff;
}
.drop-zone .dz-title {
  display: block;
  font-weight: 600;
  font-size: 1.05rem;
}
.drop-zone .dz-subtitle {
  display: block;
  font-size: 0.9rem;
  color: #6c757d;
  margin-top: 6px;
}