:root {
  --primary-color: #4F46E5;
  --primary-hover: #4338CA;
  --bg-color: #F9FAFB;
  --card-bg: #FFFFFF;
  --border-color: #E5E7EB;
  --text-primary: #111827;
  --text-secondary: #6B7280;
  --user-message-bg: #F3F4F6;
  --ai-message-bg: #EBF5FF;
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --radius: 12px;
  --modal-overlay: rgba(0, 0, 0, 0.5);
  --button-secondary: #9CA3AF;
  --button-secondary-hover: #4B5563;
  --error-color: #EF4444;
  --success-color: #10B981;
  --code-bg: #F9FAFB;
  --file-bg: #E0F2FE;
}

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

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-primary);
  line-height: 1.5;
}

#app {
  display: flex;
  justify-content: center;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: 1000px;
  display: flex;
  flex-direction: column;
  height: 100vh;
}

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

h1 {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--primary-color);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 16px;
}

.language-selector {
  display: flex;
  align-items: center;
}

.language-button {
  background-color: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  border-radius: 50%;
  width: 36px;
  height: 36px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.2s;
}

.language-button:hover {
  background-color: var(--primary-color);
  color: white;
  border-color: var(--primary-color);
}

.model-selector {
  display: flex;
  align-items: center;
  gap: 8px;
}

.model-selector label {
  font-weight: 500;
}

select {
  padding: 8px 12px;
  border-radius: 6px;
  border: 1px solid var(--border-color);
  background-color: white;
  font-size: 0.875rem;
  max-width: 180px;
}

.icon-button {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 5px;
  background: none;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  padding: 6px 10px;
  cursor: pointer;
  color: var(--text-primary);
  font-size: 0.875rem;
  transition: all 0.2s;
}

.icon-button:hover {
  background-color: var(--user-message-bg);
}

main {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.chat-container {
  flex: 1;
  overflow-y: auto;
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.welcome-message {
  text-align: center;
  margin: 3rem auto;
  max-width: 500px;
  padding: 2rem;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.welcome-message h2 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: var(--primary-color);
}

.welcome-message p {
  color: var(--text-secondary);
}

.message {
  display: flex;
  flex-direction: column;
  max-width: 80%;
  padding: 1rem;
  border-radius: var(--radius);
  animation: fadeIn 0.3s ease-out;
  position: relative;
}

.message-content {
  overflow-wrap: break-word;
  word-wrap: break-word;
}

.message-content pre {
  margin: 10px 0;
  padding: 12px;
  background-color: var(--code-bg);
  border-radius: 6px;
  overflow-x: auto;
}

.message-content code {
  font-family: 'Menlo', 'Monaco', 'Courier New', monospace;
  font-size: 0.9em;
}

.message-content p {
  margin-bottom: 8px;
}

.message-content p:last-child {
  margin-bottom: 0;
}

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

.user-message {
  background-color: var(--user-message-bg);
  align-self: flex-end;
  border-bottom-right-radius: 0;
}

.ai-message {
  background-color: var(--ai-message-bg);
  align-self: flex-start;
  border-bottom-left-radius: 0;
}

.message-actions {
  display: flex;
  gap: 5px;
  margin-top: 8px;
  opacity: 0;
  transition: opacity 0.2s;
  align-self: flex-end;
}

.message:hover .message-actions {
  opacity: 1;
}

.action-button {
  background: none;
  border: none;
  cursor: pointer;
  padding: 3px;
  border-radius: 3px;
  color: var(--text-secondary);
  transition: all 0.2s;
}

.action-button:hover {
  color: var(--primary-color);
  background-color: rgba(79, 70, 229, 0.1);
}

.thinking {
  align-self: flex-start;
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  background-color: var(--ai-message-bg);
  border-bottom-left-radius: 0;
  opacity: 0.7;
}

.dots {
  display: flex;
  gap: 4px;
}

.dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--text-secondary);
  animation: bounce 1.4s infinite ease-in-out;
  opacity: 0.7;
}

.dot:nth-child(1) { animation-delay: 0s; }
.dot:nth-child(2) { animation-delay: 0.2s; }
.dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes bounce {
  0%, 80%, 100% { transform: translateY(0); }
  40% { transform: translateY(-6px); }
}

.input-area {
  padding: 1rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 1px solid var(--border-color);
  background-color: var(--card-bg);
}

.input-container {
  display: flex;
  gap: 0.5rem;
}

.input-options {
  display: flex;
  justify-content: flex-end;
  gap: 16px;
}

.toggle-container {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.875rem;
  color: var(--text-secondary);
  cursor: pointer;
}

.toggle-container input[type="checkbox"] {
  margin-right: 5px;
}

textarea {
  flex: 1;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  font-family: inherit;
  font-size: 1rem;
  resize: none;
  outline: none;
  transition: border-color 0.2s;
  overflow-y: auto;
  max-height: 150px;
}

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

.send-button {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color 0.2s;
}

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

.send-button svg {
  width: 20px;
  height: 20px;
}

/* Modal styles */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: var(--modal-overlay);
  z-index: 1000;
  overflow: auto;
  padding: 2rem;
  box-sizing: border-box;
  align-items: center;
  justify-content: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background-color: var(--card-bg);
  border-radius: var(--radius);
  width: 100%;
  max-width: 500px;
  box-shadow: var(--shadow);
  animation: modalFadeIn 0.3s;
}

@keyframes modalFadeIn {
  from { opacity: 0; transform: translateY(-20px); }
  to { opacity: 1; transform: translateY(0); }
}

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

.modal-header h3 {
  margin: 0;
  font-size: 1.25rem;
  color: var(--text-primary);
}

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

.modal-body {
  padding: 1.5rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-weight: 500;
}

.form-group input {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  font-size: 1rem;
  font-family: inherit;
}

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

.form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 1rem;
  margin-top: 1.5rem;
}

.cancel-button, .submit-button {
  padding: 0.75rem 1.25rem;
  border-radius: 6px;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.cancel-button {
  background-color: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-color);
}

.cancel-button:hover {
  background-color: var(--user-message-bg);
}

.submit-button {
  background-color: var(--primary-color);
  color: white;
  border: none;
}

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

.error-message {
  color: var(--error-color);
}

/* Reasoning section */
.reasoning-section {
  margin-top: 8px;
  padding: 8px;
  background-color: rgba(0, 0, 0, 0.03);
  border-radius: 6px;
  font-size: 0.9em;
  color: var(--text-secondary);
  border-left: 3px solid var(--primary-color);
}

.reasoning-title {
  font-weight: 500;
  margin-bottom: 4px;
}

/* Copy tooltip */
.tooltip {
  position: absolute;
  right: 10px;
  top: 10px;
  font-size: 0.75rem;
  background-color: rgba(0, 0, 0, 0.7);
  color: white;
  padding: 3px 6px;
  border-radius: 3px;
  opacity: 0;
  transition: opacity 0.2s;
  pointer-events: none;
}

.tooltip.visible {
  opacity: 1;
}

@media (max-width: 768px) {
  header {
    flex-direction: column;
    align-items: flex-start;
    gap: 1rem;
  }
  
  .header-controls {
    width: 100%;
    flex-wrap: wrap;
  }
  
  .message {
    max-width: 90%;
  }
  
  .modal {
    padding: 1rem;
  }
}

/* 文件上传按钮 */
.upload-button {
  height: 48px;
  width: 48px;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* 文件预览区域 */
.file-preview {
  background-color: var(--file-bg);
  border-radius: 6px;
  padding: 8px 12px;
  margin-top: 8px;
  transition: all 0.3s;
}

.file-preview.hidden {
  display: none;
}

.file-preview-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.875rem;
}

.file-name {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  max-width: calc(100% - 30px);
}

.remove-file-button {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.25rem;
  cursor: pointer;
  padding: 0 5px;
  transition: color 0.2s;
}

.remove-file-button:hover {
  color: var(--error-color);
}

/* 文件附件显示 */
.file-attachment {
  margin-top: 10px;
  padding: 8px 12px;
  background-color: var(--file-bg);
  border-radius: 6px;
  display: flex;
  align-items: center;
  font-size: 0.875rem;
  gap: 8px;
}

.file-icon {
  display: flex;
  align-items: center;
  color: var(--primary-color);
}