body {
  font-family: Arial, sans-serif;
  background-color: #f9f9f9;
  margin: 0;
  padding: 20px;
}

.container {
  max-width: 900px;
  margin: 0 auto;
}

h1 {
  text-align: center;
  margin-bottom: 20px;
}

/* PDF Viewer */
#pdfViewer {
  width: 100%;
  margin-bottom: 30px;
}

canvas {
  display: block;
  margin: 20px auto;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  border-radius: 4px;
}

/* Comment Section */
#commentSection {
  width: 100%;
}

#commentForm {
  background-color: #fff;
  padding: 12px;
  border-radius: 6px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  margin-bottom: 20px;
}

#usernameInput, #commentInput {
  width: 100%;
  padding: 8px;
  margin-bottom: 8px;
  box-sizing: border-box;
  border: 1px solid #ccc;
  border-radius: 4px;
  font-size: 14px;
}

#submitComment {
  padding: 8px 12px;
  font-size: 14px;
  cursor: pointer;
  background-color: #007bff;
  color: white;
  border: none;
  border-radius: 4px;
}

#submitComment:hover {
  background-color: #0056b3;
}

/* Comments List */
#commentsList {
  background-color: #fff;
  padding: 10px;
  border-radius: 6px;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

/* Top-level comment */
.comment {
  padding: 10px 0;
  border-bottom: 1px solid #eee;
}

.comment:last-child {
  border-bottom: none;
}

/* Username + timestamp */
.comment strong {
  margin-right: 5px;
  font-size: 14px;
}

.comment .timestamp {
  font-size: 12px;
  color: #666;
  margin-left: 5px;
}

/* Reply button styling */
.comment .replyBtn {
  font-size: 12px;
  color: #007bff;
  background: none;
  border: none;
  cursor: pointer;
  margin-left: 10px;
  padding: 0;
}

.comment .replyBtn:hover {
  text-decoration: underline;
}

/* Nested replies */
.comment .replies {
  margin-left: 15px;
  margin-top: 8px;
  border-left: none;
  padding-left: 0;
}

/* Individual reply styling */
.comment .reply {
  background-color: #f1f3f4;
  padding: 8px;
  border-radius: 4px;
  margin-top: 5px;
  font-size: 13px;
}

/* Reply box */
.comment .reply-box {
  margin-top: 5px;
}

.comment .reply-box textarea {
  width: 100%;
  resize: vertical;
  padding: 5px;
  font-size: 13px;
  margin-bottom: 5px;
  border-radius: 4px;
  border: 1px solid #ccc;
}

.comment .reply-box button {
  padding: 4px 8px;
  font-size: 13px;
  cursor: pointer;
  background-color: #007bff;
  color: white;
  border: none;
  border-radius: 3px;
}

.comment .reply-box button:hover {
  background-color: #0056b3;
}