body {
  font-family: Verdana, sans-serif;
  margin: 0;
  padding: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  background-color: #f0f2f5;
  overflow: hidden;
}

/* Chat panel */
.chat-panel {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  width: 80%;               /* ✅ 99% width */
  height: 99vh;
  margin: 0 auto;
  background-color: #fff;
  box-shadow: 0 0 15px rgba(0,0,0,0.2);
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
  display: flex;
  flex-direction: column;
  z-index: 1000;
}

/* Header */
.chat-header {
  background-color: #007bff;
  color: #fff;
  padding: 15px;
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.header-buttons {
  display: flex;
  gap: 8px;
  align-items: center;
}
.header-btn {
  background: #fff;
  color: #007bff;
  border: none;
  border-radius: 5px;
  padding: 6px 12px;
  cursor: pointer;
  font-size: 14px;
  font-weight: bold;
  transition: background-color .2s ease;
}
.header-btn:hover {
  background-color: #e2e6ea;
}
.upload-btn {
  cursor: pointer;
}
.close-btn {
  background: none;
  border: none;
  color: #fff;
  font-size: 24px;
  cursor: pointer;
}

/* Messages */
.chat-messages {
  flex-grow: 1;
  padding: 15px;
  overflow-y: auto;
  background-color: #e9ecef;
  border-bottom: 1px solid #dee2e6;
}
.message {
  margin-bottom: 10px;
  padding: 8px 12px;
  border-radius: 15px;
  max-width: 95%;
  word-wrap: break-word;
}
.message.user {
  background-color: #007bff;
  color: #fff;
  align-self: flex-end;
  margin-left: auto;
}
.message.bot {
  background-color: #f8f9fa;
  color: #343a40;
  align-self: flex-start;
  margin-right: auto;
  border: 1px solid #dee2e6;
}

/* File thumbnail */
.file-thumbnail {
  display: flex;
  align-items: center;
  gap: 8px;
  background: rgba(255,255,255,0.2);
  padding: 6px 10px;
  border-radius: 8px;
  border: 1px solid rgba(255,255,255,0.3);
}
.file-icon { font-size: 36px; }
.file-name {
  font-size: 14px;
  font-weight: bold;
  color: #fff;
  word-break: break-word;
}

/* Input bar */
.chat-input {
  display: flex;
  padding: 15px;
  border-top: 1px solid #dee2e6;
  background-color: #f8f9fa;
  align-items: center;
}
.chat-input input[type="text"] {
  flex-grow: 1;
  padding: 10px;
  border: 1px solid #ced4da;
  border-radius: 20px;
  margin-right: 10px;
  font-size: 14px;
}
.chat-input button {
  padding: 10px 15px;
  background-color: #28a745;
  color: #fff;
  border: none;
  border-radius: 20px;
  cursor: pointer;
  transition: background-color .3s ease;
}
.chat-input button:hover { background-color: #218838; }

/* Headnotes */
.headnote-item {
  margin: 6px 0;
  padding: 6px;
  background: #f9f9f9;
  border-left: 3px solid #007bff;
  border-radius: 4px;
}

/* Responsive */
@media (max-width: 768px) {
  .chat-panel {
    width: 100%;
    height: 100vh;
    border-radius: 0;
  }
  .chat-header {
    border-radius: 0;
  }
}