:root {
  --primary-color: #2563eb;
  --primary-hover: #1d4ed8;
  --text-color: #111827;
  --text-light: #374151;
  --border-color: #d1d5db;
  --bg-color: #f9fafb;
  --toolbar-bg: #ffffff;
  --toolbar-border: #e5e7eb;
  --toolbar-hover: #f3f4f6;
  --toolbar-active: #e5e7eb;
  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
}

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

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

.container {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.header {
  background-color: white;
  padding: 1.25rem;
  border-bottom: 1px solid var(--border-color);
}

.header-content {
  max-width: 80rem;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text-color);
}

.logo .icon {
  color: var(--primary-color);
}

.logo h1 {
  font-size: 1.5rem;
  font-weight: 600;
  letter-spacing: -0.025em;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.625rem 1.25rem;
  background-color: var(--primary-color);
  color: white;
  border: none;
  border-radius: 0.5rem;
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

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

.main {
  flex: 1;
  max-width: 80rem;
  margin: 2rem auto;
  padding: 0 1.5rem;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2rem;
}

.editor-container,
.preview-container {
  background-color: white;
  border: 1px solid var(--border-color);
  border-radius: 0.75rem;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.panel-header {
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: var(--toolbar-bg);
}

.panel-header h2 {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-color);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

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

.action-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0.4rem;
  background-color: white;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  color: var(--text-color);
  cursor: pointer;
  transition: all 0.15s ease;
}

.action-button:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
  background-color: var(--toolbar-hover);
}

.toolbar {
  padding: 0.75rem;
  background-color: var(--toolbar-bg);
  border-bottom: 1px solid var(--border-border);
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
}

.toolbar-group {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  background-color: var(--toolbar-hover);
  padding: 0.25rem;
  border-radius: 0.375rem;
}

.toolbar-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  padding: 0.4rem;
  background-color: white;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  color: var(--text-color);
  cursor: pointer;
  transition: all 0.15s ease;
}

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

.toolbar-button.active {
  background-color: var(--primary-color);
  border-color: var(--primary-color);
  color: white;
}

.toolbar-select {
  padding: 0.375rem 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 0.375rem;
  background-color: white;
  font-size: 0.875rem;
  color: var(--text-color);
  cursor: pointer;
  min-width: 8rem;
  transition: all 0.15s ease;
}

.toolbar-select:hover {
  border-color: var(--primary-color);
}

.editor {
  flex: 1;
  width: 100%;
  min-height: 400px;
  padding: 1.25rem;
  font-family: ui-monospace, 'SF Mono', Monaco, 'Cascadia Code', 'Segoe UI Mono', monospace;
  font-size: 0.875rem;
  line-height: 1.7;
  border: none;
  resize: none;
  background-color: white;
  color: var(--text-color);
}

.editor:focus {
  outline: none;
  background-color: var(--bg-color);
}

.preview {
  flex: 1;
  width: 100%;
  min-height: 400px;
  border: none;
  background-color: white;
}

.footer {
  background-color: white;
  border-top: 1px solid var(--border-color);
  padding: 1.5rem;
  text-align: center;
  font-size: 0.875rem;
  color: var(--text-light);
}

/* Fullscreen styles */
.fullscreen {
  position: fixed !important;
  top: 0;
  left: 0;
  width: 100vw !important;
  height: 100vh !important;
  z-index: 50;
  border-radius: 0;
  border: none;
}

.fullscreen .editor,
.fullscreen .preview {
  height: calc(100vh - 8rem);
}

/* Tooltips */
[title] {
  position: relative;
}

[title]:before {
  content: attr(title);
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(-4px);
  padding: 0.5rem 0.75rem;
  background-color: var(--text-color);
  color: white;
  font-size: 0.75rem;
  border-radius: 0.375rem;
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: all 0.15s ease;
  pointer-events: none;
}

[title]:hover:before {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(-8px);
}

/* Accessibility styles */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Focus styles */
:focus {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* Focus-visible styles for better keyboard navigation */
:focus:not(:focus-visible) {
  outline: none;
}

:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 2px;
}

/* High contrast mode support */
@media (forced-colors: active) {
  .button,
  .toolbar-button,
  .action-button {
    border: 2px solid ButtonText;
  }
  
  :focus {
    outline: 2px solid ButtonText;
  }
}

/* Responsive styles */
@media (max-width: 768px) {
  .main {
    grid-template-columns: 1fr;
    margin: 1rem auto;
    padding: 0 1rem;
    gap: 1rem;
  }
  
  .header-content {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .toolbar {
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  .toolbar-group {
    flex: 1;
    justify-content: center;
  }

  .toolbar-select {
    width: 100%;
  }

  /* Hide toggle preview button on mobile */
  #togglePreview {
    display: none;
  }

  /* Always show preview below editor on mobile */
  .preview-container {
    display: block !important;
  }

  /* Ensure editor takes full width */
  .editor-container {
    width: 100%;
  }
}