/* CSS Variables for theming */
:root {
  --primary-color: #3b82f6;
  --secondary-color: #6b7280;
  --success-color: #10b981;
  --error-color: #ef4444;
  --warning-color: #f59e0b;

  --bg-color: #ffffff;
  --surface-color: #f9fafb;
  --border-color: #e5e7eb;
  --text-color: #111827;
  --text-secondary: #6b7280;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

  --border-radius: 0.5rem;
  --transition: all 0.2s ease-in-out;
}

/* Dark mode variables */
[data-theme="dark"] {
  --bg-color: #111827;
  --surface-color: #1f2937;
  --border-color: #374151;
  --text-color: #f9fafb;
  --text-secondary: #9ca3af;
}

/* Reset and base styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.6;
  transition: var(--transition);
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2rem;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: 2rem;
  padding: 2rem;
  background: var(--surface-color);
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-sm);
}

.header h1 {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
  color: var(--primary-color);
}

.header p {
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.header-controls {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.auto-convert-toggle {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem;
}

.auto-convert-toggle input[type="checkbox"] {
  margin: 0;
}

/* Mode selector */
.mode-selector {
  background: var(--surface-color);
  padding: 1.5rem;
  border-radius: var(--border-radius);
  margin-bottom: 2rem;
  box-shadow: var(--shadow-sm);
}

.mode-dropdown {
  width: 100%;
  padding: 0.75rem;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  background: var(--bg-color);
  color: var(--text-color);
  font-size: 1rem;
  margin-bottom: 1rem;
}

.options {
  display: flex;
  gap: 2rem;
  flex-wrap: wrap;
}

.option-group {
  display: flex;
  gap: 1rem;
  align-items: center;
}

.option-group label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  cursor: pointer;
  font-size: 0.9rem;
}

.option-group select {
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius);
  background: var(--bg-color);
  color: var(--text-color);
}

/* Conversion area */
.conversion-area {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 2rem;
  margin-bottom: 2rem;
  align-items: start;
}

.panel {
  background: var(--surface-color);
  border-radius: var(--border-radius);
  padding: 1.5rem;
  box-shadow: var(--shadow-md);
}

.panel-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

.panel-header h3 {
  color: var(--primary-color);
  font-size: 1.2rem;
}

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

.panel textarea {
  width: 100%;
  min-height: 200px;
  padding: 1rem;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius);
  background: var(--bg-color);
  color: var(--text-color);
  font-family: "Consolas", "Monaco", monospace;
  font-size: 0.9rem;
  resize: vertical;
  transition: var(--transition);
}

.panel textarea:focus {
  outline: none;
  border-color: var(--primary-color);
}

.panel-info {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 0.5rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.hint {
  font-style: italic;
}

.count {
  font-weight: 500;
}

/* Center controls */
.center-controls {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  align-self: center;
}

/* Buttons */
.btn {
  padding: 0.75rem 1.5rem;
  border: none;
  border-radius: var(--border-radius);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  text-decoration: none;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
}

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

.btn-primary:hover {
  background: #2563eb;
  transform: translateY(-1px);
}

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

.btn-secondary:hover {
  background: #4b5563;
}

.btn-small {
  padding: 0.5rem 1rem;
  font-size: 0.8rem;
}

.btn-large {
  padding: 1rem 2rem;
  font-size: 1.1rem;
  font-weight: 600;
}

/* Error display */
.error-display {
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: var(--error-color);
  padding: 1rem;
  border-radius: var(--border-radius);
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

[data-theme="dark"] .error-display {
  background: #1f1917;
  border-color: #78350f;
}

.close-error {
  margin-left: auto;
  background: none;
  border: none;
  font-size: 1.2rem;
  cursor: pointer;
  color: var(--error-color);
}

/* Toast notification */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background: var(--success-color);
  color: white;
  padding: 1rem 1.5rem;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow-lg);
  transform: translateY(100px);
  opacity: 0;
  transition: var(--transition);
  z-index: 1000;
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

/* FAQ Section */
.faq {
  margin: 3rem 0;
  padding: 2rem;
  background: var(--surface-color);
  border-radius: var(--border-radius);
}

.faq h2 {
  text-align: center;
  margin-bottom: 2rem;
  color: var(--primary-color);
}

.faq-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.faq-item {
  padding: 1.5rem;
  background: var(--bg-color);
  border-radius: var(--border-radius);
  border: 1px solid var(--border-color);
}

.faq-item h3 {
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.faq-item p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* Footer */
.footer {
  text-align: center;
  padding: 2rem;
  color: var(--text-secondary);
  border-top: 1px solid var(--border-color);
  margin-top: 2rem;
}

/* Responsive design */
@media (max-width: 768px) {
  .container {
    padding: 1rem;
  }

  .header h1 {
    font-size: 2rem;
  }

  .conversion-area {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .center-controls {
    order: -1;
    flex-direction: row;
    justify-content: center;
  }

  .panel textarea {
    min-height: 150px;
  }

  .faq-grid {
    grid-template-columns: 1fr;
  }

  .toast {
    bottom: 1rem;
    right: 1rem;
    left: 1rem;
  }
}

@media (max-width: 480px) {
  .header-controls {
    flex-direction: column;
  }

  .options {
    flex-direction: column;
    gap: 1rem;
  }

  .panel-controls {
    flex-wrap: wrap;
  }

  .center-controls {
    flex-direction: column;
  }
}

/* Animation for mode changes */
.panel textarea {
  transition: all 0.3s ease-in-out;
}

.conversion-area.converting .panel textarea {
  opacity: 0.7;
}

/* Loading state */
.btn.loading {
  opacity: 0.7;
  cursor: not-allowed;
}

.btn.loading::after {
  content: "";
  width: 16px;
  height: 16px;
  border: 2px solid transparent;
  border-top-color: currentColor;
  border-radius: 50%;
  animation: spin 1s linear infinite;
  margin-left: 0.5rem;
}

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