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

:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --bg-color: #f3f4f6;
  --chat-bg: #ffffff;
  --user-msg-bg: #2563eb;
  --user-msg-color: #ffffff;
  --assistant-msg-bg: #e5e7eb;
  --assistant-msg-color: #1f2937;
  --border-color: #d1d5db;
  --text-color: #374151;
  --text-muted: #6b7280;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  height: 100vh;
  overflow: hidden;
}

.container {
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-width: 900px;
  margin: 0 auto;
  background-color: var(--chat-bg);
  box-shadow: 0 0 20px rgba(0, 0, 0, 0.1);
}

/* Header */
.header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--chat-bg);
}

.header h1 {
  font-size: 1.25rem;
  font-weight: 600;
}

.header-actions {
  display: flex;
  gap: 0.5rem;
}

/* Buttons */
.btn {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  font-size: 0.875rem;
  font-weight: 500;
  transition: all 0.2s;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

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

.btn-primary:disabled {
  background-color: var(--border-color);
  cursor: not-allowed;
}

.btn-secondary {
  background-color: var(--bg-color);
  color: var(--text-color);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--border-color);
}

.btn-danger {
  background-color: #dc2626;
  color: white;
  border: none;
}

.btn-danger:hover {
  background-color: #b91c1c;
}

/* Chat Container */
.chat-container {
  display: flex;
  flex-direction: column;
  flex: 1;
  overflow: hidden;
}

/* Messages */
.messages {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.welcome-message {
  text-align: center;
  padding: 2rem;
  color: var(--text-muted);
}

.message {
  display: flex;
  max-width: 80%;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.message.user {
  align-self: flex-end;
}

.message.assistant {
  align-self: flex-start;
}

.message-content {
  padding: 0.75rem 1rem;
  border-radius: 1rem;
  line-height: 1.5;
  white-space: pre-wrap;
  word-break: break-word;
}

.message.user .message-content {
  background-color: var(--user-msg-bg);
  color: var(--user-msg-color);
  border-bottom-right-radius: 0.25rem;
}

.message.assistant .message-content {
  background-color: var(--assistant-msg-bg);
  color: var(--assistant-msg-color);
  border-bottom-left-radius: 0.25rem;
}

/* Typing indicator */
.typing-indicator {
  display: flex;
  gap: 0.25rem;
  padding: 0.75rem 1rem;
  background-color: var(--assistant-msg-bg);
  border-radius: 1rem;
  border-bottom-left-radius: 0.25rem;
  width: fit-content;
}

.typing-indicator span {
  width: 8px;
  height: 8px;
  background-color: var(--text-muted);
  border-radius: 50%;
  animation: bounce 1.4s infinite ease-in-out;
}

.typing-indicator span:nth-child(1) { animation-delay: -0.32s; }
.typing-indicator span:nth-child(2) { animation-delay: -0.16s; }

@keyframes bounce {
  0%, 80%, 100% { transform: scale(0); }
  40% { transform: scale(1); }
}

/* Input Container */
.input-container {
  display: flex;
  gap: 0.75rem;
  padding: 1rem 1.5rem;
  border-top: 1px solid var(--border-color);
  background-color: var(--chat-bg);
}

#userInput {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: 1.5rem;
  font-size: 1rem;
  font-family: inherit;
  resize: none;
  outline: none;
  transition: border-color 0.2s;
  max-height: 150px;
  line-height: 1.5;
}

#userInput:focus {
  border-color: var(--primary-color);
}

#sendBtn {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.send-icon {
  font-size: 1.25rem;
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
  z-index: 1000;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background-color: var(--chat-bg);
  border-radius: 1rem;
  width: 90%;
  max-width: 500px;
  max-height: 80vh;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
  font-size: 1.125rem;
}

.close-btn {
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--text-muted);
}

.close-btn:hover {
  color: var(--text-color);
}

.modal-body {
  padding: 1.5rem;
  overflow-y: auto;
}

/* Stats */
.stat-item {
  display: flex;
  justify-content: space-between;
  padding: 0.75rem 0;
  border-bottom: 1px solid var(--border-color);
}

.stat-item:last-child {
  border-bottom: none;
}

.stat-label {
  color: var(--text-muted);
}

.stat-value {
  font-weight: 600;
}

/* Error message */
.error-message {
  background-color: #fef2f2;
  color: #dc2626;
  padding: 0.75rem 1rem;
  border-radius: 0.5rem;
  margin: 0.5rem 0;
}

/* Scrollbar */
.messages::-webkit-scrollbar {
  width: 6px;
}

.messages::-webkit-scrollbar-track {
  background: transparent;
}

.messages::-webkit-scrollbar-thumb {
  background-color: var(--border-color);
  border-radius: 3px;
}

/* Form */
.form-group {
  margin-bottom: 1rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
  color: var(--text-color);
  font-size: 0.875rem;
}

.form-group input,
.form-group select {
  width: 100%;
  padding: 0.625rem 0.875rem;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  font-size: 0.875rem;
  font-family: inherit;
  transition: border-color 0.2s;
  background-color: white;
}

.form-group input:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--primary-color);
}

.form-group input::placeholder {
  color: var(--text-muted);
}

/* Evaluation Panel */
.evaluation-panel {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  background-color: var(--chat-bg);
  border-top: 2px solid var(--primary-color);
  max-height: 60vh;
  overflow-y: auto;
  box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.15);
  z-index: 100;
}

.evaluation-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 1.5rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-color);
  position: sticky;
  top: 0;
}

.evaluation-header h3 {
  margin: 0;
  font-size: 1rem;
  color: var(--primary-color);
}

.evaluation-content {
  padding: 1.5rem;
  line-height: 1.8;
  white-space: pre-wrap;
  font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 640px) {
  .header {
    padding: 0.75rem 1rem;
  }

  .messages {
    padding: 1rem;
  }

  .input-container {
    padding: 0.75rem 1rem;
  }

  .message {
    max-width: 90%;
  }
}