* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: Arial, sans-serif;
  background: #f5f7fb;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 30px 10px;
}

.container {
  background: #fff;
  padding: 25px 30px;
  border-radius: 12px;
  box-shadow: 0 6px 20px rgba(0,0,0,0.1);
  max-width: 600px;
  width: 100%;
  text-align: center;
}

h1 {
  color: #333;
  margin-bottom: 10px;
}

.upload-box {
  border: 2px dashed #bbb;
  border-radius: 10px;
  padding: 25px;
  background: #fafafa;
  cursor: pointer;
  margin: 20px 0;
}

.upload-box:hover {
  border-color: #007bff;
}

.upload-box p {
  color: #666;
}

ul#pdfList {
  list-style: none;
  margin: 20px 0;
  text-align: left;
  max-height: 250px;
  overflow-y: auto;
  padding: 0;
}

ul#pdfList li {
  background: #fdfdfd;
  padding: 10px 15px;
  margin-bottom: 8px;
  border-radius: 6px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border: 1px solid #eee;
  box-shadow: 0 2px 6px rgba(0,0,0,0.05);
}

li span {
  font-size: 14px;
  color: #333;
  flex: 1;
}

li button {
  background: #ff4d4f;
  border: none;
  color: white;
  padding: 5px 10px;
  border-radius: 5px;
  margin-left: 8px;
  cursor: pointer;
  font-size: 12px;
}

li button.move-up {
  background: #007bff;
}
li button.move-down {
  background: #28a745;
}

button#mergeBtn {
  margin-top: 20px;
  padding: 12px 20px;
  background: #28a745;
  border: none;
  color: white;
  font-size: 16px;
  border-radius: 8px;
  cursor: pointer;
}

button#mergeBtn:disabled {
  background: #bbb;
  cursor: not-allowed;
}

button#mergeBtn:hover:not(:disabled) {
  background: #218838;
}