:root {
  /* Minimal Palette */
  --bg-color: #fafafa;
  --surface-color: #ffffff;
  --text-primary: #18181b;
  --text-secondary: #71717a;
  --accent-color: #2563eb;
  /* Vibrant Blue */
  --accent-hover: #1d4ed8;
  --border-color: #e4e4e7;
  --error-color: #ef4444;

  /* Spacing */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;

  /* UI Elements */
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);

  /* Layout */
  --max-width: 1000px;
  --header-height: 64px;
}

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

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

/* Typography */
h1,
h2,
h3 {
  font-weight: 600;
  letter-spacing: -0.025em;
  color: var(--text-primary);
}

a {
  color: var(--accent-color);
  text-decoration: none;
  transition: color 0.2s;
}

a:hover {
  color: var(--accent-hover);
}

/* Layout Containers */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* Header */
header {
  background-color: var(--surface-color);
  border-bottom: 1px solid var(--border-color);
  height: var(--header-height);
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

header h1 {
  font-size: 1.25rem;
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

header h1 i {
  color: var(--text-primary);
  /* Keep it monochrome or accent? Monochrome fits minimal. */
}

/* Mobile Friendly Nav */
header nav button {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.4rem 0.8rem;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.2s;
}

header nav button:hover {
  background-color: var(--bg-color);
  border-color: var(--text-secondary);
}

/* Main Layout */
.app-container {
  display: flex;
  flex-direction: column-reverse;
  /* Put preview on top on mobile? No, logically input first usually. Let's stick to column. */
  flex-direction: column;
  gap: var(--spacing-lg);
  padding: var(--spacing-lg) 0;
}

/* Card Styles */
.generator-section,
.preview-section,
.history-section,
.scan-section,
.help-container,
.privacy-container {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: var(--spacing-lg);
  box-shadow: var(--shadow-sm);
}

/* Input Groups */
.input-group {
  margin-bottom: var(--spacing-lg);
}

.input-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
  color: var(--text-primary);
}

.input-group textarea {
  width: 100%;
  padding: var(--spacing-sm);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  font-family: inherit;
  font-size: 1rem;
  min-height: 80px;
  resize: vertical;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group textarea:focus {
  outline: none;
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.char-count {
  text-align: right;
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: var(--spacing-xs);
}

/* Custom Image Upload & Modes */
.image-upload-container {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-sm);
}

.custom-file-btn {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.6rem 1rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s;
}

.custom-file-btn:hover {
  background: var(--bg-color);
  border-color: var(--text-secondary);
}

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

.file-name {
  font-size: 0.85rem;
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 150px;
}

.image-mode-container {
  margin-top: var(--spacing-sm);
  padding: var(--spacing-sm);
  background: var(--bg-color);
  border-radius: var(--radius-md);
  border: 1px dashed var(--border-color);
}

.mode-label {
  display: block;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: var(--spacing-xs);
  color: var(--text-primary);
}

.mode-options {
  display: flex;
  gap: var(--spacing-md);
}

.radio-label {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  cursor: pointer;
}

.radio-label input {
  accent-color: var(--text-primary);
}

/* Customization Grid */
.customization-options {
  display: grid;
  grid-template-columns: 1fr;
  /* Mobile first: 1 col */
  gap: var(--spacing-md);
  margin-bottom: var(--spacing-lg);
}

.option-group label {
  display: block;
  font-size: 0.8rem;
  font-weight: 500;
  margin-bottom: var(--spacing-xs);
  color: var(--text-secondary);
}

.option-group select,
.option-group input[type="file"],
.option-group input[type="color"] {
  width: 100%;
  padding: 0.5rem;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  background-color: var(--surface-color);
  font-size: 0.9rem;
  color: var(--text-primary);
  cursor: pointer;
}

.option-group input[type="color"] {
  height: 40px;
  padding: 0.25rem;
}

/* Templates */
.qr-templates h3 {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: var(--spacing-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.template-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  margin-bottom: var(--spacing-lg);
}

.template-buttons button {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.4rem 0.8rem;
  border-radius: 9999px;
  /* Pill shape */
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.template-buttons button:hover {
  background: var(--border-color);
}

/* Primary Button */
.primary-btn {
  width: 100%;
  background-color: var(--text-primary);
  /* Minimal black button */
  color: white;
  border: none;
  padding: 0.875rem;
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: var(--spacing-sm);
  transition: background-color 0.2s, transform 0.1s;
}

.primary-btn:hover {
  background-color: #000;
  transform: translateY(-1px);
}

.primary-btn:active {
  transform: translateY(0);
}

/* Preview Section */
.preview-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  order: -1;
  /* For mobile: maybe show preview first? No, let's keep inputs first. Removing this for now. */
}

.qr-container {
  width: 100%;
  max-width: 300px;
  aspect-ratio: 1/1;
  background: white;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: var(--spacing-lg);
  position: relative;
  overflow: hidden;
  margin-left: auto;
  margin-right: auto;
}

.qr-container canvas,
.qr-container img {
  max-width: 100%;
  height: auto;
}

.qr-container .placeholder {
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--spacing-sm);
}

.qr-container .placeholder i {
  font-size: 2.5rem;
  opacity: 0.2;
}

.qr-actions {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--spacing-sm);
  width: 100%;
}

.secondary-btn {
  background: var(--surface-color);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  padding: 0.6rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  /* Stack icon and text for better mobile fit? or just row */
  align-items: center;
  justify-content: center;
  gap: 0.25rem;
  transition: all 0.2s;
}

.secondary-btn i {
  font-size: 1rem;
  color: var(--text-secondary);
}

.secondary-btn:hover:not(:disabled) {
  background-color: var(--bg-color);
  border-color: var(--text-secondary);
}

.secondary-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

/* History Section */
.history-section h2,
.scan-section h2 {
  font-size: 1.1rem;
  margin-bottom: 0;
  color: var(--text-primary);
}

.history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--spacing-md);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: var(--spacing-sm);
}

.text-btn {
  background: none;
  border: none;
  font-size: 0.85rem;
  padding: 0.4rem 0.6rem;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-weight: 600;
}

.text-btn.danger-text {
  color: var(--error-color);
}

.text-btn.danger-text:hover {
  background: #fef2f2;
  /* red-50 */
}

.history-grid {
  display: grid;
  /* Mobile History: Text only */
  grid-template-columns: 1fr;
  gap: var(--spacing-sm);
}

.history-item {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-sm);
  cursor: pointer;
  transition: border-color 0.2s;
}

.history-item:hover {
  border-color: var(--accent-color);
}

.history-item img {
  display: none;
  /* Hide image on mobile */
}

.history-item p {
  font-size: 0.9rem;
  color: var(--text-primary);
  word-break: break-all;
  /* Ensure long URLs break */
  white-space: normal;
  text-align: left;
  width: 100%;
}

/* Scanner */
.scanner-container {
  width: 100%;
  overflow: hidden;
  border-radius: var(--radius-md);
  background: black;
  position: relative;
  aspect-ratio: 4/3;
  margin-bottom: var(--spacing-md);
}

#scanner {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* Footer */
footer {
  margin-top: auto;
  padding: var(--spacing-xl) 0;
  border-top: 1px solid var(--border-color);
  background-color: var(--bg-color);
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
  text-align: center;
}

.footer-brand h3 {
  font-size: 1rem;
  margin-bottom: var(--spacing-xs);
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: var(--spacing-lg);
}

.footer-links a {
  color: var(--text-secondary);
  font-size: 0.875rem;
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.footer-links a:hover {
  color: var(--text-primary);
}

.footer-bottom {
  text-align: center;
  margin-top: var(--spacing-lg);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.875rem;
}

/* Help & Privacy Specifics */
.help-section,
.privacy-section {
  margin-bottom: var(--spacing-lg);
}

.help-section h3,
.privacy-section h3 {
  font-size: 1.1rem;
  margin-bottom: var(--spacing-md);
  color: var(--text-primary);
  border-bottom: 1px solid var(--border-color);
  padding-bottom: var(--spacing-sm);
}

.help-item,
.privacy-note {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-md);
}

.help-item h4 {
  font-size: 0.95rem;
  margin-bottom: var(--spacing-sm);
  color: var(--text-primary);
}

.help-item ul,
.help-item ol,
.privacy-section ul {
  padding-left: var(--spacing-lg);
  color: var(--text-secondary);
  font-size: 0.9rem;
}

.help-item li,
.privacy-section li {
  margin-bottom: var(--spacing-xs);
}

.privacy-note {
  background-color: #eff6ff;
  /* subtle blue tint */
  border-color: #dbeafe;
  display: flex;
  gap: var(--spacing-md);
  align-items: flex-start;
}

.privacy-note i {
  color: var(--accent-color);
  font-size: 1.25rem;
  margin-top: 2px;
}

.privacy-features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.feature {
  background: var(--bg-color);
  padding: var(--spacing-md);
  border-radius: var(--radius-md);
  text-align: center;
  border: 1px solid var(--border-color);
}

.feature i {
  font-size: 1.5rem;
  color: var(--accent-color);
  margin-bottom: var(--spacing-sm);
}

.contact-section {
  background: var(--bg-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-lg);
  margin-top: var(--spacing-xl);
  text-align: center;
}

.contact-link {
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: var(--spacing-sm);
}

/* Utilities */
.hidden {
  display: none !important;
}

/* Desktop Logic (Tablet and up) */
@media (min-width: 768px) {
  .app-container {
    flex-direction: row;
    align-items: flex-start;
  }

  .generator-section {
    flex: 2;
  }

  .preview-section {
    flex: 1;
    position: sticky;
    top: calc(var(--header-height) + var(--spacing-lg));
  }

  .customization-options {
    grid-template-columns: repeat(2, 1fr);
  }

  .qr-actions {
    grid-template-columns: 1fr 1fr 1fr;
    /* Keep buttons side by side or stack? Row is better for desktop */
  }

  .footer-content {
    flex-direction: row;
    justify-content: space-between;
    text-align: left;
  }

  .history-grid {
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  }

  .history-item {
    flex-direction: column;
    text-align: center;
    justify-content: center;
    padding: var(--spacing-sm);
  }

  .history-item img {
    display: block;
    max-width: 100%;
    height: auto;
    border-radius: var(--radius-sm);
    margin-bottom: var(--spacing-xs);
  }

  .history-item p {
    font-size: 0.75rem;
    color: var(--text-secondary);
    text-align: center;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
  }
}