/* ============================================================
   QR Builder — Design Tokens & Global Styles
   ============================================================ */

/* --- Design Tokens --- */
:root {
  /* Colors */
  --color-primary: #2563eb;
  --color-primary-hover: #1d4ed8;
  --color-error: #d946ef;
  --color-warning: #f59e0b;
  --color-success: #16a34a;
  --color-bg: #ffffff;
  --color-bg-secondary: #f8fafc;
  --color-text: #0f172a;
  --color-text-secondary: #64748b;
  --color-border: #e2e8f0;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;

  /* Typography */
  --font-family: system-ui, -apple-system, sans-serif;
  --font-size-sm: 14px;
  --font-size-base: 16px;
  --font-size-lg: 18px;
  --font-size-xl: 24px;
  --font-size-2xl: 32px;
  --line-height: 1.5;

  /* Borders */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.07);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
}

/* --- Dark Mode --- */
@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-text: #f1f5f9;
    --color-text-secondary: #94a3b8;
    --color-border: #334155;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.4);
  }
}

/* ============================================================
   Reset & Base
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: var(--font-size-base);
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  min-width: 320px;
  overflow-x: hidden;
}

a,
a:visited,
a:hover,
a:active {
  color: #d946ef;
}

/* ============================================================
   Accessibility
   ============================================================ */

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

/* Focus indicators — WCAG 2.1 AA compliant */
:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Reduced motion */
@media (prefers-reduced-motion: no-preference) {
  *,
  *::before,
  *::after {
    transition-duration: var(--transition-fast);
  }
}

/* ============================================================
   Header
   ============================================================ */
.app-header {
  background-color: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  padding: var(--space-md) var(--space-lg);
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-content {
  max-width: 1400px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Brand / Logo */
.app-brand {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.brand-link {
  display: inline-block;
  line-height: 0;
  text-decoration: none;
}

.brand-logo {
  height: 48px;
  width: auto;
  display: block;
}

.brand-copyright {
  font-size: 11px;
  color: var(--color-text-secondary);
  line-height: 1.2;
  margin: 0;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

/* ============================================================
   Main Layout
   ============================================================ */
.app-main {
  max-width: 1400px;
  margin: 0 auto;
  padding: var(--space-lg);
}

/* Mobile-first: stacked vertical */
.app-layout {
  display: flex;
  flex-direction: column;
  gap: var(--space-xl);
}

/* Desktop: side-by-side at ≥768px */
@media (min-width: 768px) {
  .app-layout {
    flex-direction: row;
    align-items: flex-start;
  }

  .controls-panel {
    flex: 1 1 0%;
    min-width: 0;
    max-width: 560px;
  }

  .preview-panel {
    flex: 1 1 0%;
    min-width: 0;
    position: sticky;
    top: 80px;
  }
}

.controls-panel {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.preview-panel {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

/* ============================================================
   Section Heading Row — heading + help button
   ============================================================ */
.section-heading-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.section-heading-row .section-heading {
  margin-bottom: 0;
}

/* Help Button */
.btn-help {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  padding: 0;
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  font-weight: 600;
  line-height: 1;
  color: #d946ef;
  background-color: rgba(217, 70, 239, 0.1);
  border: 1px solid #d946ef;
  border-radius: 50%;
  cursor: pointer;
  flex-shrink: 0;
}

.btn-help:hover {
  color: #ffffff;
  background-color: #d946ef;
  border-color: #d946ef;
}

/* Smaller help button for sub-section legends */
.btn-help-sm {
  width: 20px;
  height: 20px;
  font-size: 12px;
}

/* Legend row — legend text + help button side by side */
.legend-row {
  display: inline-flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-sm);
  width: 100%;
}

/* ============================================================
   Help Dialog
   ============================================================ */
.help-dialog {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 0;
  max-width: 560px;
  width: calc(100% - var(--space-xl) * 2);
  max-height: 80vh;
  background-color: var(--color-bg);
  color: var(--color-text);
  box-shadow: var(--shadow-md);
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  margin: 0;
}

.help-dialog::backdrop {
  background-color: rgba(0, 0, 0, 0.5);
}

.help-dialog .dialog-content {
  display: flex;
  flex-direction: column;
  max-height: 80vh;
}

.help-dialog .dialog-content h2 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-md);
  flex-shrink: 0;
}

.help-dialog-body {
  overflow-y: auto;
  flex: 1;
  font-size: var(--font-size-sm);
  line-height: 1.7;
  color: var(--color-text);
  margin-bottom: var(--space-lg);
}

.help-dialog-body p {
  margin-bottom: var(--space-md);
}

.help-dialog-body strong {
  font-weight: 600;
}

.help-dialog-body ul {
  margin: var(--space-sm) 0 var(--space-md) var(--space-lg);
  padding: 0;
}

.help-dialog-body li {
  margin-bottom: var(--space-xs);
}

.help-dialog .btn {
  flex-shrink: 0;
  align-self: flex-end;
}

/* ============================================================
   Sections & Headings
   ============================================================ */
.section-heading {
  font-size: var(--font-size-lg);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-md);
}

.section-input,
.section-customization,
.section-preview,
.section-export {
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
}

.section-data-type {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
  background-color: rgba(37, 99, 235, 0.06);
  border-color: #22d3ee;
}

@media (prefers-color-scheme: dark) {
  .section-data-type {
    background-color: rgba(37, 99, 235, 0.12);
  }
}

/* ============================================================
   Form Controls — General
   ============================================================ */
fieldset {
  border: none;
  padding: 0;
  margin: 0;
}

legend {
  font-size: var(--font-size-base);
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: var(--space-sm);
  width: 100%;
}

label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text);
  margin-bottom: var(--space-xs);
}

input[type="text"],
input[type="url"],
input[type="tel"],
input[type="email"],
input[type="number"],
textarea,
select {
  display: block;
  width: 100%;
  padding: var(--space-sm) var(--space-md);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
}

input[type="text"]:focus,
input[type="url"]:focus,
input[type="tel"]:focus,
input[type="email"]:focus,
input[type="number"]:focus,
textarea:focus,
select:focus {
  border-color: #ffffff;
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.25);
  outline: none;
}

textarea {
  resize: vertical;
  min-height: 80px;
}

select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2364748b' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-md) center;
  padding-right: var(--space-xl);
}

/* ============================================================
   Input Groups
   ============================================================ */
.input-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.input-group[hidden] {
  display: none;
}

.input-group-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--space-sm);
}

/* ============================================================
   Color Picker
   ============================================================ */
.color-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  margin-bottom: var(--space-sm);
}

.color-row label {
  margin-bottom: 0;
  flex-shrink: 0;
}

input[type="color"] {
  width: 48px;
  height: 36px;
  padding: 2px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  background: none;
}

input[type="color"]::-webkit-color-swatch-wrapper {
  padding: 2px;
}

input[type="color"]::-webkit-color-swatch {
  border: none;
  border-radius: 2px;
}

input[type="color"]::-moz-color-swatch {
  border: none;
  border-radius: 2px;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-top: var(--space-sm);
}

.checkbox-row label {
  margin-bottom: 0;
  font-weight: 400;
  cursor: pointer;
}

input[type="checkbox"] {
  width: 18px;
  height: 18px;
  accent-color: var(--color-primary);
  cursor: pointer;
  flex-shrink: 0;
}

/* ============================================================
   Data Type Dropdown & Description
   ============================================================ */
.data-type-description {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  margin-top: var(--space-sm);
  line-height: var(--line-height);
}

/* ============================================================
   Radio Inline — (reserved for future use)
   ============================================================ */
.radio-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

/* ============================================================
   Shape Row — Module Style & Corner Eye Style side-by-side
   ============================================================ */
.shape-row {
  display: flex;
  gap: var(--space-md);
}

.shape-field {
  flex: 1;
  min-width: 0;
}

/* ============================================================
   Radio Option — Error Correction Level
   ============================================================ */
#ec-level-selector {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-sm);
}

.radio-option {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: var(--space-sm);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  text-align: center;
  margin-bottom: 0;
}

.radio-option input[type="radio"] {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.radio-option:has(input:checked) {
  border-color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.06);
}

.radio-option:has(input:focus-visible) {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.radio-option-label {
  font-size: var(--font-size-base);
  font-weight: 700;
  color: var(--color-text);
}

.radio-option-desc {
  font-size: 12px;
  color: var(--color-text-secondary);
}

.recommendation {
  font-size: var(--font-size-sm);
  color: var(--color-warning);
  margin-top: var(--space-sm);
  font-weight: 500;
}

/* ============================================================
   Customization Groups
   ============================================================ */
.customization-group {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
}

.customization-group:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.customization-group:first-child {
  padding-top: var(--space-md);
}

.customization-divider-first {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 0 0 0 0;
}

/* ============================================================
   Range Slider — Quiet Zone
   ============================================================ */
.quiet-zone-control {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.range-with-value {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

input[type="range"] {
  flex: 1;
  height: 6px;
  appearance: none;
  background: var(--color-border);
  border-radius: 3px;
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  appearance: none;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  border: 2px solid var(--color-bg);
  box-shadow: var(--shadow-sm);
}

input[type="range"]::-moz-range-thumb {
  width: 20px;
  height: 20px;
  border-radius: 50%;
  background: var(--color-primary);
  cursor: pointer;
  border: 2px solid var(--color-bg);
  box-shadow: var(--shadow-sm);
}

input[type="range"]:focus-visible::-webkit-slider-thumb {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

output {
  min-width: 28px;
  text-align: center;
  font-size: var(--font-size-sm);
  font-weight: 600;
  color: var(--color-text);
}

/* ============================================================
   Buttons
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  font-family: var(--font-family);
  font-size: var(--font-size-base);
  font-weight: 500;
  line-height: var(--line-height);
  border: 1px solid transparent;
  border-radius: var(--radius-md);
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  user-select: none;
}

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

.btn-primary {
  color: #ffffff;
  background-color: var(--color-primary);
  border-color: var(--color-primary);
}

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

.btn-danger {
  color: #ffffff;
  background-color: var(--color-error);
  border-color: var(--color-error);
}

.btn-icon {
  padding: var(--space-sm);
  color: var(--color-text-secondary);
  background: none;
  border-color: transparent;
  border-radius: var(--radius-md);
  font-size: var(--font-size-lg);
  line-height: 1;
}

.btn-sm {
  padding: var(--space-xs) var(--space-md);
  font-size: var(--font-size-sm);
}

/* Button hover/active — wrapped in reduced-motion check */
@media (prefers-reduced-motion: no-preference) {
  .btn {
    transition: background-color var(--transition-fast),
                border-color var(--transition-fast),
                color var(--transition-fast),
                box-shadow var(--transition-fast);
  }
}

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

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

.btn-danger:not(:disabled):hover {
  background-color: #c026d3;
  border-color: #c026d3;
}

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

/* ============================================================
   Tooltips
   ============================================================ */
.tooltip {
  display: block;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: var(--space-xs) var(--space-sm);
  margin-top: var(--space-xs);
}

/* ============================================================
   Field Errors
   ============================================================ */
.field-error {
  font-size: var(--font-size-sm);
  color: var(--color-error);
  min-height: 0;
  margin-top: var(--space-xs);
}

.field-error:empty {
  display: none;
}

/* Error state on inputs */
.input-group:has(.field-error:not(:empty)) input,
.input-group:has(.field-error:not(:empty)) textarea,
.input-group:has(.field-error:not(:empty)) select {
  border-color: var(--color-error);
}

.input-group:has(.field-error:not(:empty)) input:focus,
.input-group:has(.field-error:not(:empty)) textarea:focus,
.input-group:has(.field-error:not(:empty)) select:focus {
  box-shadow: 0 0 0 3px rgba(217, 70, 239, 0.15);
}

/* ============================================================
   Drop Zone — Logo Upload
   ============================================================ */
.drop-zone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-xl) var(--space-lg);
  border: 2px dashed var(--color-border);
  border-radius: var(--radius-lg);
  text-align: center;
  cursor: pointer;
  background-color: var(--color-bg-secondary);
}

.drop-zone.drag-over {
  border-color: var(--color-primary);
  background-color: rgba(37, 99, 235, 0.06);
}

.drop-zone-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.drop-zone-hint {
  font-size: 12px;
  color: var(--color-text-secondary);
}

/* Logo Preview */
.logo-preview {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background-color: var(--color-bg-secondary);
  margin-top: var(--space-sm);
}

.logo-preview[hidden] {
  display: none;
}

.logo-preview img {
  width: 48px;
  height: 48px;
  object-fit: contain;
  border-radius: var(--radius-sm);
  border: 1px solid var(--color-border);
}

/* ============================================================
   Preview Area
   ============================================================ */
.preview-canvas-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  min-height: 280px;
  overflow: hidden;
}

#qr-canvas {
  max-width: 100%;
  height: auto;
  display: block;
}

.preview-placeholder {
  position: absolute;
  text-align: center;
  color: var(--color-text-secondary);
  font-size: var(--font-size-base);
  padding: var(--space-lg);
}

/* ============================================================
   Scan Indicator
   ============================================================ */
.scan-indicator {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-size: var(--font-size-sm);
  font-weight: 500;
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
}

.scan-status-icon {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  flex-shrink: 0;
  background-color: var(--color-text-secondary);
}

.scan-indicator[data-status="ok"] .scan-status-icon {
  background-color: var(--color-success);
}

.scan-indicator[data-status="at-risk"] .scan-status-icon {
  background-color: var(--color-warning);
}

.scan-indicator[data-status="unscannable"] .scan-status-icon {
  background-color: var(--color-error);
}

.scan-status-text {
  color: var(--color-text);
}

.scan-warnings {
  list-style: none;
  padding: 0;
  margin: 0;
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
}

.scan-warnings li {
  padding: var(--space-xs) 0;
}

/* ============================================================
   Export Bar
   ============================================================ */
.export-bar {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.export-primary {
  display: flex;
  flex-wrap: nowrap;
  gap: var(--space-sm);
  align-items: center;
}

.download-group {
  display: flex;
  gap: 0;
}

.download-group .btn {
  border-top-right-radius: 0;
  border-bottom-right-radius: 0;
}

.download-group select {
  border-top-left-radius: 0;
  border-bottom-left-radius: 0;
  border-left: none;
  width: auto;
  min-width: 72px;
  padding: var(--space-sm) var(--space-md);
  font-size: var(--font-size-sm);
  background-color: var(--color-bg);
}

.export-secondary {
  display: flex;
  justify-content: flex-start;
}

/* ============================================================
   Toast Notifications
   ============================================================ */
.toast-container {
  position: fixed;
  bottom: var(--space-lg);
  right: var(--space-lg);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  max-width: 400px;
  pointer-events: none;
}

.toast {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  background-color: var(--color-text);
  color: var(--color-bg);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-md);
  font-size: var(--font-size-sm);
  pointer-events: auto;
}

.toast-success {
  background-color: var(--color-success);
  color: #ffffff;
}

.toast-error {
  background-color: var(--color-error);
  color: #ffffff;
}

.toast-warning {
  background-color: var(--color-warning);
  color: #000000;
}

@media (prefers-reduced-motion: no-preference) {
  .toast {
    animation: toast-slide-in var(--transition-normal) ease-out;
  }

  @keyframes toast-slide-in {
    from {
      opacity: 0;
      transform: translateY(16px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
}

/* ============================================================
   Keyboard Shortcuts Dialog
   ============================================================ */
.shortcuts-dialog {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: 0;
  max-width: 480px;
  width: calc(100% - var(--space-xl) * 2);
  background-color: var(--color-bg);
  color: var(--color-text);
  box-shadow: var(--shadow-md);
  position: fixed;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  margin: 0;
}

.shortcuts-dialog::backdrop {
  background-color: rgba(0, 0, 0, 0.5);
}

.dialog-content {
  padding: var(--space-xl);
}

.dialog-content h2 {
  font-size: var(--font-size-xl);
  font-weight: 600;
  margin-bottom: var(--space-lg);
}

.shortcuts-list {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin-bottom: var(--space-lg);
}

.shortcut-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-sm) 0;
  border-bottom: 1px solid var(--color-border);
}

.shortcut-item:last-child {
  border-bottom: none;
}

.shortcut-item dt {
  display: flex;
  gap: var(--space-xs);
  align-items: center;
}

.shortcut-item dd {
  color: var(--color-text-secondary);
  font-size: var(--font-size-sm);
}

kbd {
  display: inline-block;
  padding: 2px var(--space-sm);
  font-family: var(--font-family);
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text);
  background-color: var(--color-bg-secondary);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  box-shadow: 0 1px 0 var(--color-border);
  line-height: 1.4;
}

/* ============================================================
   Error Banner — Global
   ============================================================ */
.error-banner {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 900;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
  padding: var(--space-md) var(--space-lg);
  background-color: var(--color-error);
  color: #ffffff;
  font-size: var(--font-size-sm);
  font-weight: 500;
}

.error-banner[hidden] {
  display: none;
}

.error-banner .btn {
  color: var(--color-error);
  background-color: #ffffff;
  border-color: #ffffff;
}

/* ============================================================
   Tip Jar Footer
   ============================================================ */
.tip-jar-footer {
  max-width: 1400px;
  margin: var(--space-xl) auto 0;
  padding: 0 var(--space-lg) var(--space-xl);
  text-align: center;
  background: transparent;
}

.tip-jar-content {
  max-width: 520px;
  margin: 0 auto;
}

.tip-jar-text {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin-bottom: var(--space-md);
}

.tip-jar-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-lg);
}

.tip-jar-btn {
  padding: 0;
  background: none;
  border: none;
  cursor: pointer;
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
}

@media (prefers-reduced-motion: no-preference) {
  .tip-jar-btn {
    transition: transform var(--transition-fast);
  }
  .tip-jar-btn:hover {
    transform: scale(1.08);
  }
}

.tip-jar-qr {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
}

.tip-jar-qr-label {
  font-size: 10px;
  color: var(--color-text-secondary);
}

/* ============================================================
   Responsive Adjustments
   ============================================================ */

/* Mid-width screens — stack export buttons */
@media (max-width: 900px) {
  .export-primary {
    flex-wrap: wrap;
  }
}

/* Small screens */
@media (max-width: 480px) {
  .app-main {
    padding: var(--space-md);
  }

  .section-data-type,
  .section-input,
  .section-customization,
  .section-preview,
  .section-export {
    padding: var(--space-md);
  }

  #ec-level-selector {
    grid-template-columns: repeat(2, 1fr);
  }

  .export-primary {
    flex-direction: column;
    align-items: stretch;
  }

  .download-group {
    width: 100%;
  }

  .download-group .btn {
    flex: 1;
  }

  .toast-container {
    left: var(--space-md);
    right: var(--space-md);
    max-width: none;
  }
}

/* Large screens */
@media (min-width: 1200px) {
  .controls-panel {
    max-width: 600px;
  }
}

/* Very large screens */
@media (min-width: 1920px) {
  .app-main {
    max-width: 1600px;
  }
}