/* ═══════════════════════════════════════════════════════════════════════════
   CMB Card Number Calculator — Complete Stylesheet
   Mobile-first responsive design with light/dark theme support
   ═══════════════════════════════════════════════════════════════════════════ */

/* ─── CSS Custom Properties (Light Theme) ──────────────────────────────── */
:root {
  /* Colors */
  --color-bg: #f5f5f7;
  --color-surface: #ffffff;
  --color-surface-hover: #f9fafb;
  --color-surface-elevated: #ffffff;
  --color-border: #e5e7eb;
  --color-border-focus: #3b82f6;

  --color-text-primary: #1f2937;
  --color-text-secondary: #6b7280;
  --color-text-tertiary: #9ca3af;
  --color-text-inverse: #ffffff;

  --color-accent: #2563eb;
  --color-accent-hover: #1d4ed8;
  --color-accent-light: #dbeafe;
  --color-accent-text: #ffffff;

  --color-success: #10b981;
  --color-success-light: #d1fae5;
  --color-warning: #f59e0b;
  --color-warning-light: #fef3c7;
  --color-error: #ef4444;
  --color-error-light: #fee2e2;
  --color-info: #3b82f6;
  --color-info-light: #dbeafe;

  /* Card structure colors */
  --bin-color: #2563eb;
  --bin-bg: #dbeafe;
  --region-color: #7c3aed;
  --region-bg: #ede9fe;
  --variable-color: #d97706;
  --variable-bg: #fef3c7;
  --check-color: #dc2626;
  --check-bg: #fee2e2;

  /* Chip colors */
  --chip-bg: #f3f4f6;
  --chip-text: #374151;
  --chip-border: #d1d5db;
  --chip-selected-bg: #2563eb;
  --chip-selected-text: #ffffff;
  --chip-selected-border: #2563eb;

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

  /* Border radius */
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;

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

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Noto Sans SC', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --font-mono: 'SF Mono', 'Cascadia Code', 'Consolas', 'Liberation Mono', 'Courier New', monospace;

  --text-xs: 0.75rem;    /* 12px */
  --text-sm: 0.875rem;   /* 14px */
  --text-base: 1rem;     /* 16px */
  --text-lg: 1.125rem;   /* 18px */
  --text-xl: 1.25rem;    /* 20px */
  --text-2xl: 1.5rem;    /* 24px */

  /* Transitions */
  --transition-fast: 0.15s ease;
  --transition-normal: 0.25s ease;

  /* Layout */
  --max-width: 960px;
  --header-height: 60px;
}

/* ─── Dark Theme ────────────────────────────────────────────────────────── */
[data-theme="dark"] {
  --color-bg: #0f172a;
  --color-surface: #1e293b;
  --color-surface-hover: #273548;
  --color-surface-elevated: #1e293b;
  --color-border: #334155;
  --color-border-focus: #60a5fa;

  --color-text-primary: #f1f5f9;
  --color-text-secondary: #94a3b8;
  --color-text-tertiary: #64748b;
  --color-text-inverse: #0f172a;

  --color-accent: #3b82f6;
  --color-accent-hover: #60a5fa;
  --color-accent-light: #1e3a5f;
  --color-accent-text: #ffffff;

  --color-success: #34d399;
  --color-success-light: #064e3b;
  --color-warning: #fbbf24;
  --color-warning-light: #78350f;
  --color-error: #f87171;
  --color-error-light: #7f1d1d;
  --color-info: #60a5fa;
  --color-info-light: #1e3a5f;

  --bin-color: #60a5fa;
  --bin-bg: #1e3a5f;
  --region-color: #a78bfa;
  --region-bg: #2e1065;
  --variable-color: #fbbf24;
  --variable-bg: #78350f;
  --check-color: #f87171;
  --check-bg: #7f1d1d;

  --chip-bg: #334155;
  --chip-text: #cbd5e1;
  --chip-border: #475569;
  --chip-selected-bg: #3b82f6;
  --chip-selected-text: #ffffff;
  --chip-selected-border: #60a5fa;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.4);
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: 1.6;
  color: var(--color-text-primary);
  background: var(--color-bg);
  min-height: 100vh;
}

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

a:hover {
  text-decoration: underline;
}

img, svg {
  max-width: 100%;
  display: block;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
  color: inherit;
}

input, select, textarea {
  font-family: inherit;
  font-size: inherit;
  color: inherit;
}

/* ─── Layout ────────────────────────────────────────────────────────────── */
.app-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-md);
}

/* ─── Header ────────────────────────────────────────────────────────────── */
.app-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.header-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-sm) var(--space-md);
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: var(--header-height);
}

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

.app-logo {
  font-size: 1.5rem;
  line-height: 1;
}

.app-title {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text-primary);
  white-space: nowrap;
}

.app-subtitle {
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

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

.theme-toggle {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-full);
  border: 1px solid var(--color-border);
  background: var(--color-surface);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  transition: all var(--transition-fast);
  cursor: pointer;
}

.theme-toggle:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-accent);
}

/* ─── Cards ─────────────────────────────────────────────────────────────── */
.card {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--color-border);
  padding: var(--space-lg);
  margin-bottom: var(--space-md);
}

.card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: var(--space-md);
}

.card-title {
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-text-primary);
}

.card-subtitle {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

/* ─── Form Elements ─────────────────────────────────────────────────────── */
.form-group {
  margin-bottom: var(--space-md);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.form-hint {
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
  margin-top: 2px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-md);
}

@media (min-width: 640px) {
  .form-row {
    grid-template-columns: 1fr 1fr;
  }
  .form-row-3 {
    grid-template-columns: 1fr 1fr 1fr;
  }
}

.form-input,
.form-select {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  color: var(--color-text-primary);
  font-size: var(--text-base);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
  appearance: none;
  -webkit-appearance: none;
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px var(--color-accent-light);
}

.form-input::placeholder {
  color: var(--color-text-tertiary);
}

.form-input.input-mono {
  font-family: var(--font-mono);
  letter-spacing: 2px;
  font-size: 1.1rem;
}

.form-select {
  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 d='M6 8L1 3h10z' fill='%236b7280'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}

/* ─── Card Structure Visualization ─────────────────────────────────────── */
.card-structure {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  align-items: center;
  padding: var(--space-md) 0;
  overflow-x: auto;
}

.structure-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  min-width: 44px;
}

.structure-digits {
  padding: 8px 12px;
  border-radius: var(--radius-md);
  font-family: var(--font-mono);
  font-size: clamp(14px, 3vw, 20px);
  font-weight: 700;
  letter-spacing: 1px;
  color: #ffffff;
  text-align: center;
}

.structure-separator {
  font-size: 1.2rem;
  color: var(--color-text-tertiary);
  font-weight: 300;
  margin: 0 2px;
}

.structure-label {
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--color-text-tertiary);
  margin-top: 4px;
}

.structure-block-bin .structure-digits { background: var(--bin-color); }
.structure-block-region .structure-digits { background: var(--region-color); }
.structure-block-variable .structure-digits {
  background: var(--variable-color);
  letter-spacing: 3px;
}
.structure-block-check .structure-digits { background: var(--check-color); }

.structure-stats {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  margin-top: var(--space-sm);
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
}

.structure-stat {
  display: flex;
  align-items: center;
  gap: 4px;
}

.structure-stat strong {
  color: var(--color-text-primary);
}

/* ─── Pattern Chips ─────────────────────────────────────────────────────── */
.chip-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 8px 14px;
  border-radius: var(--radius-full);
  border: 2px solid var(--chip-border);
  background: var(--chip-bg);
  color: var(--chip-text);
  font-size: var(--text-sm);
  font-weight: 600;
  cursor: pointer;
  user-select: none;
  -webkit-user-select: none;
  transition: all var(--transition-fast);
  -webkit-tap-highlight-color: transparent;
  white-space: nowrap;
}

.chip:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-light);
}

.chip:active {
  transform: scale(0.96);
}

.chip.selected {
  background: var(--chip-selected-bg);
  color: var(--chip-selected-text);
  border-color: var(--chip-selected-border);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.3);
}

.chip.selected:hover {
  background: var(--color-accent-hover);
}

.chip-icon {
  font-size: 1rem;
  line-height: 1;
}

.chip-desc {
  display: none;
  font-size: var(--text-xs);
  color: var(--color-text-tertiary);
}

@media (min-width: 640px) {
  .chip {
    padding: 10px 18px;
  }
  .chip-desc {
    display: inline;
  }
}

/* ─── Custom Tail Input ─────────────────────────────────────────────────── */
.custom-tail-wrap {
  margin-top: var(--space-md);
  padding: var(--space-md);
  background: var(--color-accent-light);
  border-radius: var(--radius-md);
  border: 1px dashed var(--color-accent);
  display: none;
}

.custom-tail-wrap.visible {
  display: block;
}

.custom-tail-wrap .form-input {
  background: var(--color-surface);
}

/* ─── Toggle Switch ─────────────────────────────────────────────────────── */
.toggle-group {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.toggle-switch {
  position: relative;
  width: 44px;
  height: 26px;
  background: var(--color-border);
  border-radius: var(--radius-full);
  cursor: pointer;
  transition: background var(--transition-fast);
}

.toggle-switch.active {
  background: var(--color-accent);
}

.toggle-switch::after {
  content: '';
  position: absolute;
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  background: white;
  border-radius: 50%;
  transition: transform var(--transition-fast);
  box-shadow: var(--shadow-sm);
}

.toggle-switch.active::after {
  transform: translateX(18px);
}

.toggle-label {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-primary);
  user-select: none;
}

/* ─── Action Bar ────────────────────────────────────────────────────────── */
.action-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin: var(--space-lg) 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  padding: 12px 24px;
  border-radius: var(--radius-md);
  font-size: var(--text-sm);
  font-weight: 600;
  transition: all var(--transition-fast);
  white-space: nowrap;
  user-select: none;
  -webkit-user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.btn:active {
  transform: scale(0.97);
}

.btn-primary {
  background: var(--color-accent);
  color: var(--color-accent-text);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--color-accent-hover);
  box-shadow: var(--shadow-md);
}

.btn-primary:disabled {
  background: var(--color-border);
  color: var(--color-text-tertiary);
  cursor: not-allowed;
  box-shadow: none;
}

.btn-secondary {
  background: var(--color-surface);
  color: var(--color-text-primary);
  border: 1.5px solid var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-light);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-secondary);
  padding: 8px 12px;
}

.btn-ghost:hover {
  background: var(--color-surface-hover);
  color: var(--color-text-primary);
}

.btn-sm {
  padding: 6px 12px;
  font-size: var(--text-xs);
}

.btn-icon {
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
}

/* ─── Distance Panel ────────────────────────────────────────────────────── */
.distance-panel {
  display: none;
}

.distance-panel.visible {
  display: block;
}

.distance-result {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  background: var(--color-info-light);
  border: 1px solid var(--color-info);
  display: none;
}

.distance-result.visible {
  display: block;
}

.distance-result-icon {
  font-size: 1.5rem;
  margin-bottom: var(--space-xs);
}

.distance-result-title {
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.distance-result-detail {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  line-height: 1.8;
}

.distance-error {
  margin-top: var(--space-md);
  padding: var(--space-md);
  border-radius: var(--radius-md);
  background: var(--color-error-light);
  border: 1px solid var(--color-error);
  color: var(--color-error);
  font-size: var(--text-sm);
  display: none;
}

.distance-error.visible {
  display: block;
}

/* ─── Progress Bar ──────────────────────────────────────────────────────── */
.progress-bar-wrap {
  display: none;
  margin: var(--space-md) 0;
}

.progress-bar-wrap.visible {
  display: block;
}

.progress-bar {
  width: 100%;
  height: 6px;
  background: var(--color-border);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: var(--color-accent);
  border-radius: var(--radius-full);
  transition: width 0.3s ease;
  width: 0%;
}

.progress-text {
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  margin-top: 4px;
  text-align: center;
}

/* ─── Results Table ─────────────────────────────────────────────────────── */
.results-panel {
  display: none;
}

.results-panel.visible {
  display: block;
}

.results-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-sm);
  margin-bottom: var(--space-md);
}

.results-count {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.results-count strong {
  color: var(--color-accent);
  font-weight: 700;
}

.results-actions {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.results-table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
}

.results-table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--text-sm);
}

.results-table thead {
  background: var(--color-surface-hover);
  position: sticky;
  top: 0;
}

.results-table th {
  padding: 10px 12px;
  text-align: left;
  font-weight: 700;
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  white-space: nowrap;
  border-bottom: 2px solid var(--color-border);
}

.results-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--color-border);
  white-space: nowrap;
}

.results-table tbody tr:hover {
  background: var(--color-surface-hover);
}

.results-table tbody tr:last-child td {
  border-bottom: none;
}

.col-number {
  font-family: var(--font-mono);
  letter-spacing: 1px;
  font-weight: 600;
}

.col-tail {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: 1.5px;
}

.col-distance {
  font-weight: 600;
  text-align: right;
}

/* Pattern badges in table */
.pattern-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
}

.pattern-badge {
  display: inline-block;
  padding: 2px 8px;
  border-radius: var(--radius-full);
  font-size: 11px;
  font-weight: 700;
  background: var(--color-accent-light);
  color: var(--color-accent);
}

.pattern-badge.badge-4A,
.pattern-badge.badge-5A,
.pattern-badge.badge-6A,
.pattern-badge.badge-7A {
  background: var(--color-success-light);
  color: var(--color-success);
}

.pattern-badge.badge-asc,
.pattern-badge.badge-desc {
  background: var(--color-warning-light);
  color: var(--color-warning);
}

/* Copy button in table */
.copy-btn {
  opacity: 0.5;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 4px 8px;
  font-size: var(--text-xs);
  cursor: pointer;
  transition: all var(--transition-fast);
  color: var(--color-text-secondary);
}

.copy-btn:hover {
  opacity: 1;
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-light);
}

.copy-btn.copied {
  background: var(--color-success-light);
  border-color: var(--color-success);
  color: var(--color-success);
  opacity: 1;
}

/* ─── Empty State ───────────────────────────────────────────────────────── */
.empty-state {
  text-align: center;
  padding: var(--space-2xl) var(--space-md);
  color: var(--color-text-secondary);
}

.empty-state-icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
  opacity: 0.5;
}

.empty-state-title {
  font-size: var(--text-lg);
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--space-xs);
}

.empty-state-desc {
  font-size: var(--text-sm);
  max-width: 360px;
  margin: 0 auto;
}

/* ─── 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);
}

.toast {
  padding: 12px 20px;
  border-radius: var(--radius-md);
  color: white;
  font-size: var(--text-sm);
  font-weight: 600;
  box-shadow: var(--shadow-lg);
  animation: toast-in 0.3s ease;
  max-width: 320px;
}

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

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

.toast-info {
  background: var(--color-info);
}

@keyframes toast-in {
  from {
    transform: translateY(20px);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

@keyframes toast-out {
  from {
    transform: translateY(0);
    opacity: 1;
  }
  to {
    transform: translateY(20px);
    opacity: 0;
  }
}

/* ─── Info / FAQ Section ────────────────────────────────────────────────── */
.info-details {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.info-details summary {
  padding: var(--space-md);
  font-weight: 700;
  cursor: pointer;
  user-select: none;
  background: var(--color-surface-hover);
  transition: background var(--transition-fast);
}

.info-details summary:hover {
  background: var(--color-border);
}

.info-content {
  padding: var(--space-md);
  font-size: var(--text-sm);
  line-height: 1.8;
  color: var(--color-text-secondary);
}

.info-content h3 {
  font-size: var(--text-base);
  color: var(--color-text-primary);
  margin: var(--space-md) 0 var(--space-xs);
}

.info-content h3:first-child {
  margin-top: 0;
}

.info-content ol,
.info-content ul {
  padding-left: 1.5em;
  margin: var(--space-xs) 0;
}

.info-content code {
  background: var(--color-surface-hover);
  padding: 2px 6px;
  border-radius: 4px;
  font-family: var(--font-mono);
  font-size: 0.9em;
}

.info-content .highlight {
  background: var(--color-warning-light);
  padding: 2px 6px;
  border-radius: 4px;
  font-weight: 600;
}

/* ─── Footer ────────────────────────────────────────────────────────────── */
.app-footer {
  text-align: center;
  padding: var(--space-xl) var(--space-md);
  color: var(--color-text-tertiary);
  font-size: var(--text-xs);
}

.app-footer a {
  color: var(--color-text-secondary);
}

/* ─── Utilities ─────────────────────────────────────────────────────────── */
.text-mono {
  font-family: var(--font-mono);
}

.text-center { text-align: center; }
.text-right { text-align: right; }
.text-sm { font-size: var(--text-sm); }
.text-xs { font-size: var(--text-xs); }
.font-bold { font-weight: 700; }

.mt-sm { margin-top: var(--space-sm); }
.mt-md { margin-top: var(--space-md); }
.mt-lg { margin-top: var(--space-lg); }
.mb-sm { margin-bottom: var(--space-sm); }
.mb-md { margin-bottom: var(--space-md); }

.hidden { display: none !important; }

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

/* ─── Search Space Warning ──────────────────────────────────────────────── */
.search-warning {
  display: none;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-md);
  font-size: var(--text-xs);
  margin-top: var(--space-sm);
}

.search-warning.visible {
  display: block;
}

.search-warning.warn {
  background: var(--color-warning-light);
  color: var(--color-warning);
  border: 1px solid var(--color-warning);
}

.search-warning.error {
  background: var(--color-error-light);
  color: var(--color-error);
  border: 1px solid var(--color-error);
}

.search-warning.info {
  background: var(--color-info-light);
  color: var(--color-info);
  border: 1px solid var(--color-info);
}

/* ─── Responsive Fine-Tuning ────────────────────────────────────────────── */

/* Tablet */
@media (min-width: 640px) {
  .app-container {
    padding: var(--space-lg);
  }

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

  .results-table {
    font-size: var(--text-base);
  }

  .results-table th,
  .results-table td {
    padding: 12px 16px;
  }

  .chip {
    font-size: var(--text-base);
  }
}

/* Desktop */
@media (min-width: 1024px) {
  .app-container {
    padding: var(--space-xl) var(--space-2xl);
  }

  .form-row {
    grid-template-columns: 1fr 1fr 1fr;
  }

  .card-structure {
    justify-content: center;
  }
}

/* Print styles - remove backgrounds for printing */
@media print {
  .app-header,
  .action-bar,
  .pattern-panel,
  .chip-group,
  .btn,
  .theme-toggle,
  .app-footer {
    display: none !important;
  }

  body {
    background: white;
    color: black;
  }

  .card {
    box-shadow: none;
    border: 1px solid #ccc;
    break-inside: avoid;
  }

  .results-table th,
  .results-table td {
    border-color: #ccc;
    color: black;
  }
}