:root {
  --bg-primary: #212121;
  --bg-secondary: #171717;
  --bg-tertiary: #2f2f2f;
  --text-primary: #ececec;
  --text-secondary: #b4b4b4;
  --text-muted: #8e8ea0;
  --border-color: #424242;
  --accent-color: #ab68ff;
  --accent-hover: #9c5cf7;
  --success-color: #10a37f;
  --sidebar-width: 260px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-primary);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
}

/* Sidebar Styles */
.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: var(--sidebar-width);
  height: 100vh;
  background-color: var(--bg-secondary);
  display: flex;
  flex-direction: column;
  transform: translateX(-100%);
  transition: transform 0.3s ease;
  z-index: 1000;
  border-right: 1px solid var(--border-color);
}

.sidebar.show {
  transform: translateX(0);
}

.sidebar-header {
  padding: 12px;
  border-bottom: 1px solid var(--border-color);
}

.new-chat-btn {
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  font-size: 14px;
  padding: 10px 16px;
  border-radius: 8px;
  transition: all 0.2s ease;
}

.new-chat-btn:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--border-color);
  color: var(--text-primary);
}

.sidebar-content {
  flex: 1;
  overflow-y: auto;
  padding: 8px 12px;
}

.sidebar-nav {
  margin-bottom: 20px;
}

.nav-item {
  display: flex;
  align-items: center;
  padding: 10px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s ease;
  color: var(--text-secondary);
  font-size: 14px;
  margin-bottom: 2px;
}

.nav-item:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.chat-section-title {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin: 16px 0 8px 12px;
}

.chat-item {
  padding: 8px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s ease;
  margin-bottom: 2px;
  color: var(--text-secondary);
  font-size: 14px;
  position: relative;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.chat-item:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.chat-item.active {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.sidebar-footer {
  padding: 12px;
  border-top: 1px solid var(--border-color);
}

.upgrade-section {
  margin-bottom: 12px;
}

.upgrade-item {
  display: flex;
  align-items: center;
  padding: 8px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s ease;
  color: var(--text-secondary);
}

.upgrade-item:hover {
  background-color: var(--bg-tertiary);
}

.upgrade-title {
  font-size: 14px;
  color: var(--text-primary);
  font-weight: 500;
}

.upgrade-subtitle {
  font-size: 12px;
  color: var(--text-muted);
}

.user-profile {
  padding: 8px 12px;
  border-radius: 8px;
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.user-profile:hover {
  background-color: var(--bg-tertiary);
}

.avatar {
  font-size: 24px;
  color: var(--text-secondary);
}

.username {
  font-weight: 500;
  color: var(--text-primary);
  font-size: 14px;
}

/* Main Content */
.main-content {
  margin-left: 0;
  justify-content: space-around;
  height: 100vh;
  display: flex;
  flex-direction: column;
  transition: margin-left 0.3s ease;
  background-color: var(--bg-primary);
  width: 100%;
}

.chat-header {
  padding: 12px 16px;
  background-color: var(--bg-primary);
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 1px solid var(--border-color);
  min-height: 60px;
}

.header-center {
  display: flex;
  align-items: center;
  gap: 12px;
  flex: 1;
  justify-content: center;
}

.model-selector {
  display: flex;
  align-items: center;
  color: var(--text-primary);
  font-weight: 600;
  font-size: 18px;
  cursor: pointer;
}

.get-plus-btn {
  background-color: var(--accent-color);
  border: none;
  color: white;
  font-size: 13px;
  padding: 6px 12px;
  border-radius: 20px;
  font-weight: 500;
}

.get-plus-btn:hover {
  background-color: var(--accent-hover);
}

.header-actions {
  display: flex;
  gap: 8px;
}

.sidebar-toggle {
  padding: 8px;
  color: var(--text-secondary);
}

/* Chat Messages */
/* .chat-messages {
  padding: 1rem;
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  max-width: 768px;
  margin: 0 auto;
  width: 100%;
  max-height: calc(100vh - 180px);
  min-height: 0;
} */
.chat-messages {
  max-height: calc(100vh - 180px); /* Keep this for upper limit */
  min-height: 200px; /* Minimum height to avoid collapse */
  overflow-y: auto; /* Ensure container scrolls */
  flex: 1 1 auto; /* Allow growth but control shrinkage */
  padding: 1rem;
  display: flex;
  flex-direction: column;
  width: 100%;
  max-width: 768px;
  margin: 0 auto;
}

.welcome-message {
  display: flex;
  align-items: center;
  justify-content: center;
  flex: 1;
  text-align: center;
  padding: 40px 20px;
}

.welcome-title {
  font-size: 32px;
  font-weight: 400;
  color: var(--text-primary);
  margin: 0;
  line-height: 1.2;
}

/* Message Bubbles */
.message {
  display: flex;
  margin-bottom: 1rem;
  animation: fadeIn 0.3s ease;
  max-height: none;
  overflow-y: none;
  word-wrap: break-word;
  padding: 0.5rem;
}

.message.user {
  justify-content: flex-end;
}

.message.bot {
  justify-content: flex-start;
}

.message-content {
  padding: 1rem;
  border-radius: 1rem;
  position: relative;
  overflow-x: auto;
  /* white-space: pre-wrap; */
  word-break: break-word;
}

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

.message.bot .message-content {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-bottom-left-radius: 0.25rem;
}

.message-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 0.5rem;
  font-size: 1.2rem;
}

.message.user .message-avatar {
  background-color: var(--accent-color);
  order: 2;
}

.message.bot .message-avatar {
  background-color: var(--bg-tertiary);
  color: var(--accent-color);
}

/* OCR pre block styling & copy button */
.message .message-content .ocr-toolbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 6px;
}

.copy-ocr-btn {
  background: transparent;
  border: 1px solid rgba(0,0,0,0.12);
  padding: 4px 8px;
  border-radius: 6px;
  font-size: 0.85rem;
  cursor: pointer;
}

.copy-ocr-btn.copied {
  background: #2b2b2b;
  color: #fff;
  border-color: transparent;
}

/* OCR text appearance - more compact and readable */
.message .message-content pre.ocr-text {
  /* Consistent spacing */
  padding: 0.75rem;
  margin: 0.5rem 0;
  font-size: 0.9rem;
  line-height: 1.4;
  max-height: 340px;
}

/* small meta text next to copy */
.ocr-meta {
  font-size: 0.75rem;
  color: rgba(255,255,255,0.6);
}

/* overall bubble max height adjustment */
.chat-messages .message { 
  max-height: 420px; 
  overflow-y: none; 
}

/* reduce spacing so blocks don't look jammed */
.message .message-content { 
  padding: 6px; 
}

/* Loading Animation */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  padding: 1rem;
}

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

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

@keyframes typing {
  0%,
  80%,
  100% {
    transform: scale(0.8);
    opacity: 0.5;
  }
  40% {
    transform: scale(1);
    opacity: 1;
  }
}

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

/* Input Area */
.input-area {
  /* Consistent padding */
  padding: 1.25rem 1rem 2rem;
  background-color: var(--bg-primary);
  display: flex;
  justify-content: center;
  position: relative;
  z-index: 10;
}

.input-container {
  max-width: 768px;
  width: 100%;
  position: relative;
}

.input-row {
  /* More consistent spacing */
  padding: 0.75rem 1rem;
  min-height: 48px;
  gap: 0.5rem;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 24px;
  transition: all 0.2s ease;
}

.input-row:focus-within {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 2px rgba(171, 104, 255, 0.1);
}

.text-input-wrapper {
  flex: 1;
  min-width: 0;
}

.message-input {
  background: transparent;
  border: none;
  color: var(--text-primary);
  resize: none;
  min-height: 24px;
  max-height: 200px;
  font-size: 16px;
  line-height: 1.5;
  outline: none;
  width: 100%;
  overflow-y: auto;
}

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

.file-upload-btn,
.send-btn,
.explanation-level-btn {
  width: 32px;
  height: 32px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: transparent;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s ease;
  flex-shrink: 0;
}

.file-upload-btn:hover,
.explanation-level-btn:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.send-btn {
  background-color: var(--text-primary);
  color: var(--bg-primary);
}

.send-btn:disabled {
  background-color: var(--text-muted);
  cursor: not-allowed;
}

.send-btn:not(:disabled):hover {
  background-color: var(--text-primary);
  transform: scale(1.05);
}

.explanation-level-wrapper {
  position: relative;
  flex-shrink: 0;
}

.explanation-level-menu {
  position: absolute;
  bottom: 40px;
  right: 0;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 4px;
  min-width: 180px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  z-index: 1000;
  display: none;
}

.explanation-level-menu.show {
  display: block;
}

.explanation-option {
  padding: 8px 12px;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.2s ease;
  color: var(--text-secondary);
  font-size: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.explanation-option:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

.explanation-option.active {
  background-color: var(--accent-color);
  color: white;
}

.upload-menu {
  position: absolute;
  bottom: 40px;
  left: 0;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 4px;
  min-width: 160px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
  z-index: 1000;
  display: none;
}

.upload-menu.show {
  display: block;
}

.upload-option {
  padding: 8px 12px;
  border-radius: 4px;
  cursor: pointer;
  transition: background-color 0.2s ease;
  color: var(--text-secondary);
  font-size: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.upload-option:hover {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
}

/* File Preview */
.file-preview {
  margin-top: 8px;
  padding: 12px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
}

.file-info {
  display: flex;
  align-items: center;
  gap: 8px;
}

.file-name {
  flex: 1;
  color: var(--text-secondary);
  font-size: 14px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.remove-file {
  padding: 4px;
  border-radius: 4px;
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s ease;
}

.remove-file:hover {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
}

/* Ensure full viewport usage */
html,
body {
  height: 100%;
  overflow: hidden;
}

/* Responsive Design */
@media (min-width: 1024px) {
  .sidebar {
    transform: translateX(0);
    position: fixed;
  }

  .main-content {
    margin-left: var(--sidebar-width);
    width: calc(100% - var(--sidebar-width));
    /* padding-bottom: 30px; */
  }

  .sidebar-toggle {
    display: none;
  }
}

@media (max-width: 1023px) {
  .main-content {
    margin-left: 0;
    /* padding-bottom: 30px; */
    width: 100%;
  }

  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.show {
    transform: translateX(0);
  }
}

@media (max-width: 768px) {
  .chat-messages {
    /* Consistent padding on mobile */
    padding: 0.75rem;
  }

  .message-content {
    /* Better spacing on mobile */
    padding: 0.75rem;
    max-width: 85%;
  }

  .input-area {
    /* Consistent mobile padding */
    padding: 1rem 0.75rem 1.5rem;
  }
}

@media (max-width: 576px) {
  .chat-header {
    padding: 12px;
  }

  .chat-messages {
    padding: 12px;
  }

  .input-area {
    padding: 12px 8px 20px;
  }

  .input-row {
    padding: 8px 10px;
    gap: 6px;
  }

  .file-upload-btn,
  .send-btn,
  .explanation-level-btn {
    width: 28px;
    height: 28px;
    border-radius: 14px;
  }

  .message-content {
    max-width: 90%;
    padding: 12px;
  }

  .welcome-title {
    font-size: 20px;
  }

  .get-plus-btn {
    display: none;
  }

  .explanation-level-menu,
  .upload-menu {
    min-width: 140px;
    font-size: 13px;
  }

  .explanation-option,
  .upload-option {
    padding: 6px 10px;
  }
}

@media (max-width: 600px) {
  .message .message-content pre.ocr-text { 
    font-size: 0.82rem; 
    max-height: 220px; 
  }
}

/* Tablet improvements */
@media (min-width: 768px) and (max-width: 1023px) {
  .main-content {
    width: 100%;
    height: 100vh;
    margin-left: 0;
  }

  .input-area {
    padding: 18px 16px 28px;
  }

  .welcome-title {
    font-size: 28px;
  }
}

/* Custom Scrollbar */
.sidebar-content::-webkit-scrollbar,
.chat-messages::-webkit-scrollbar,
.message-input::-webkit-scrollbar {
  width: 4px;
}

.sidebar-content::-webkit-scrollbar-track,
.chat-messages::-webkit-scrollbar-track,
.message-input::-webkit-scrollbar-track {
  background: transparent;
}

.sidebar-content::-webkit-scrollbar-thumb,
.chat-messages::-webkit-scrollbar-thumb,
.message-input::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 2px;
}

.sidebar-content::-webkit-scrollbar-thumb:hover,
.chat-messages::-webkit-scrollbar-thumb:hover,
.message-input::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}