:root {
  --primary-color: #2563eb;
  --bg-color: #f8fafc;
  --sidebar-bg: #ffffff;
  --chat-bg: #ffffff;
  --text-color: #1e293b;
  --border-color: #e2e8f0;
  --hover-color: #f1f5f9;
  --message-user-bg: #f8fafc;
  --message-bot-bg: #ffffff;
  --mobile-breakpoint: 768px;
  --sidebar-width: 300px;
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.5;
}

.app-container {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  height: 100vh;
  max-width: 1920px;
  margin: 0 auto;
  position: relative;
}

.sidebar {
  background-color: var(--sidebar-bg);
  border-right: 1px solid var(--border-color);
  padding: 1rem;
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-header h1 {
  font-size: 1.5rem;
  margin-bottom: 1rem;
}

.new-chat-btn {
  width: 100%;
  padding: 0.75rem;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  transition: opacity 0.2s;
}

.new-chat-btn:hover {
  opacity: 0.9;
}

.pdf-list {
  flex: 1;
  overflow-y: auto;
  padding: 1rem 0;
}

.pdf-list h2 {
  font-size: 0.875rem;
  text-transform: uppercase;
  color: #64748b;
  margin-bottom: 0.5rem;
}

.pdf-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem;
  border-radius: 0.5rem;
  cursor: pointer;
  margin-bottom: 0.5rem;
}

.pdf-item:hover {
  background-color: var(--hover-color);
}

.pdf-item.active {
  background-color: var(--hover-color);
}

.upload-section {
  padding-top: 1rem;
  border-top: 1px solid var(--border-color);
}

.upload-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  width: 100%;
  padding: 0.75rem;
  background-color: var(--hover-color);
  border-radius: 0.5rem;
  cursor: pointer;
  transition: background-color 0.2s;
}

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

.chat-container {
  display: flex;
  flex-direction: column;
  background-color: var(--chat-bg);
}

.chat-messages {
  flex: 1;
  overflow-y: auto;
  padding: 2rem;
}

.message {
  max-width: 80%;
  margin-bottom: 1.5rem;
  padding: 1rem;
  border-radius: 0.5rem;
  animation: fadeIn 0.3s ease-in-out;
}

.message.user {
  background-color: var(--message-user-bg);
  margin-left: auto;
  border: 1px solid var(--border-color);
}

.message.bot {
  background-color: var(--message-bot-bg);
  margin-right: auto;
  border: 1px solid var(--border-color);
  line-height: 1.6;
}

.message.bot h1,
.message.bot h2,
.message.bot h3 {
  margin: 1em 0 0.5em;
}

.message.bot p {
  margin: 0 0 1em;
}

.message.bot code {
  font-family: 'Menlo', 'Monaco', 'Courier New', monospace;
  padding: 0.2em 0.4em;
  background-color: var(--hover-color);
  border-radius: 0.3em;
}

.message.bot pre {
  background-color: var(--hover-color);
  padding: 1em;
  border-radius: 0.5em;
  overflow-x: auto;
  margin: 1em 0;
}

.message.bot pre code {
  padding: 0;
  background-color: transparent;
}

.message.bot .citation {
  cursor: pointer;
  color: var(--primary-color);
  transition: opacity 0.2s;
}

.message.bot .citation:hover {
  opacity: 0.8;
}

.message.bot ul,
.message.bot ol {
  margin: 0 0 1em;
  padding-left: 2em;
}

.message.bot blockquote {
  border-left: 4px solid var(--border-color);
  margin: 0 0 1em;
  padding-left: 1em;
  color: #64748b;
}

.message.bot table {
  border-collapse: collapse;
  margin: 1em 0;
  width: 100%;
}

.message.bot th,
.message.bot td {
  border: 1px solid var(--border-color);
  padding: 0.5em;
  text-align: left;
}

.message.bot th {
  background-color: var(--hover-color);
}

.message.streaming {
  position: relative;
}

.message.streaming::after {
  content: "";
  display: inline-block;
  width: 12px;
  height: 12px;
  border: 2px solid var(--primary-color);
  border-radius: 50%;
  border-top-color: transparent;
  animation: spinner 0.6s linear infinite;
  position: absolute;
  right: 1rem;
  top: 1rem;
}

@keyframes spinner {
  to {
    transform: rotate(360deg);
  }
}

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

.chat-input-container {
  padding: 1rem 2rem;
  border-top: 1px solid var(--border-color);
  display: flex;
  gap: 1rem;
}

#userInput {
  flex: 1;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 0.5rem;
  resize: none;
  font-family: inherit;
  font-size: 1rem;
  line-height: 1.5;
}

#userInput:focus {
  outline: none;
  border-color: var(--primary-color);
}

.send-btn {
  padding: 0.75rem;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: 0.5rem;
  cursor: pointer;
  transition: opacity 0.2s;
}

.send-btn:hover {
  opacity: 0.9;
}

.metrics-container {
  padding: 0.5rem 2rem;
  border-bottom: 1px solid var(--border-color);
  background-color: var(--bg-color);
}

.metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 1rem;
  font-size: 0.875rem;
}

.metric-group {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.metric-label {
  color: #64748b;
  font-weight: 500;
}

.metric-value {
  font-weight: 600;
  color: var(--text-color);
}

.delete-pdf-btn {
  background: none;
  border: none;
  padding: 0.25rem;
  cursor: pointer;
  opacity: 0.6;
  transition: opacity 0.2s;
  margin-left: auto;
}

.delete-pdf-btn:hover {
  opacity: 1;
}

.pdf-name {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.chat-list {
  margin-top: 1rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1rem;
}

.chat-list-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0.75rem;
  border-radius: 0.5rem;
  cursor: pointer;
  margin-bottom: 0.5rem;
}

.chat-item-content {
  flex: 1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  margin-right: 0.5rem;
}

.delete-chat-btn {
  background: none;
  border: none;
  padding: 0.25rem;
  cursor: pointer;
  opacity: 0.6;
  transition: opacity 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.delete-chat-btn:hover {
  opacity: 1;
  color: #ef4444;
}

.chat-list-item:hover {
  background-color: var(--hover-color);
}

.chat-list-item.active {
  background-color: var(--hover-color);
}

.pdf-preview-container {
  position: fixed;
  top: 0;
  right: 0;
  width: 50%;
  height: 100vh;
  background: white;
  border-left: 1px solid var(--border-color);
  z-index: 1000;
  transform: translateX(100%);
  transition: transform 0.3s ease;
  display: flex;
  flex-direction: column;
}

.pdf-preview-container.active {
  transform: translateX(0);
}

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

.pdf-preview-content {
  position: relative;
  padding: 1rem;
  overflow: auto;
}

.pdf-preview-canvas {
  display: block;
  margin: 0 auto;
  max-width: 100%;
}

.highlighted-text {
  background-color: rgba(255, 255, 0, 0.3);
  cursor: pointer;
}

.pdf-text-layer {
  opacity: 0.2;
  line-height: 1.0;
}

.pdf-text-layer span {
  color: transparent;
  position: absolute;
  white-space: pre;
  cursor: text;
  transform-origin: 0% 0%;
}

.pdf-text-layer .highlighted-text {
  background-color: rgba(255, 255, 0, 0.4);
  opacity: 1;
  color: transparent;
  mix-blend-mode: multiply;
}

.pdf-zoom-controls {
  position: absolute;
  top: 1rem;
  right: 1rem;
  display: flex;
  gap: 0.5rem;
  z-index: 10;
}

.pdf-zoom-controls button {
  padding: 0.5rem;
  background: white;
  border: 1px solid var(--border-color);
  border-radius: 0.25rem;
  cursor: pointer;
  font-size: 1rem;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.pdf-zoom-controls button:hover {
  background: var(--hover-color);
}

.pdf-zoom-controls .zoom-fit {
  width: auto;
  padding: 0 0.75rem;
}

@media (max-width: 768px) {
  .app-container {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: fixed;
    left: -100%;
    width: 100%;
    height: 100vh;
    z-index: 1000;
    transition: left 0.3s ease;
  }

  .sidebar.active {
    left: 0;
  }

  .sidebar-toggle {
    display: block;
    position: fixed;
    top: 1rem;
    left: 1rem;
    z-index: 1001;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 0.5rem;
    padding: 0.5rem;
    cursor: pointer;
  }

  .sidebar-close {
    display: block;
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    color: var(--text-color);
    cursor: pointer;
  }

  .chat-container {
    padding-top: 4rem;
  }

  .chat-messages {
    padding: 1rem;
  }

  .message {
    max-width: 95%;
  }

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

  #userInput {
    font-size: 16px;
    padding: 0.5rem;
  }

  .send-btn {
    padding: 0.5rem;
  }

  .pdf-item, 
  .upload-btn,
  .new-chat-btn {
    padding: 1rem;
    min-height: 44px;
  }

  .chat-messages {
    -webkit-overflow-scrolling: touch;
  }

  pre {
    max-width: 100%;
    overflow-x: auto;
  }

  .message.bot pre {
    margin: 0.5em -1rem;
    padding: 1rem;
    border-radius: 0;
  }

  .message.bot table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }

  .metrics-container {
    padding: 0.5rem 1rem;
  }
  
  .metrics {
    gap: 1rem;
  }

  .pdf-preview-container {
    width: 100%;
  }
}

.sidebar,
.chat-container,
.message {
  transition: all 0.3s ease;
}

@media (hover: none) {
  .pdf-item:hover,
  .upload-btn:hover,
  .new-chat-btn:hover {
    background-color: inherit;
  }

  .pdf-item:active,
  .upload-btn:active,
  .new-chat-btn:active {
    background-color: var(--hover-color);
  }
}

@media (prefers-contrast: high) {
  :root {
    --primary-color: #0000ff;
    --border-color: #000000;
    --text-color: #000000;
  }
}