/* ==========================================================================
   MINDSPRINT — DARK NEO-BRUTALISM DESIGN SYSTEM
   Thick borders, hard offset shadows, high contrast, bold geometric shapes.
   ========================================================================== */

:root {
  /* Dark base canvas */
  --bg-main: #111111;
  --bg-secondary: #191919;
  --surface-dark: #242424;
  --surface-dark-hover: #2e2e2e;

  /* Warm brutalist off-white surfaces */
  --surface: #F4F0E8;
  --surface-muted: #E6E0D5;

  /* Outlines and shadows */
  --border-color: #050505;
  --border-width: 3px;
  --shadow-color: #050505;
  --shadow-sm: 3px 3px 0 var(--shadow-color);
  --shadow-md: 5px 5px 0 var(--shadow-color);
  --shadow-lg: 8px 8px 0 var(--shadow-color);
  --shadow-pressed: 1px 1px 0 var(--shadow-color);

  /* Typography */
  --font-main: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
  --text-primary: #F8F5EE;
  --text-secondary: #C4C0B8;
  --text-dark: #111111;
  --text-muted: #888888;

  /* Saturated flat accent colors */
  --accent-yellow: #FFE66D;
  --accent-lime: #C6F55F;
  --accent-pink: #FF77B7;
  --accent-cyan: #70E5FF;
  --accent-purple: #B8A1FF;
  --accent-orange: #FF9B54;

  /* Active theme accent (default: yellow) */
  --accent: var(--accent-yellow);

  /* Functional alert colors */
  --success: #A8F05F;
  --error: #FF6B6B;
  --warning: #FFE66D;

  /* Radii */
  --radius-card: 10px;
  --radius-btn: 8px;
  --radius-badge: 4px;

  /* Sizing */
  --container-max: 1150px;
  --transition-fast: 0.12s cubic-bezier(0.16, 1, 0.3, 1);
}

/* User Accent Color overrides */
body[data-accent="lime"] { --accent: var(--accent-lime); }
body[data-accent="pink"] { --accent: var(--accent-pink); }
body[data-accent="cyan"] { --accent: var(--accent-cyan); }
body[data-accent="purple"] { --accent: var(--accent-purple); }
body[data-accent="orange"] { --accent: var(--accent-orange); }

/* Spacing density */
body[data-density="compact"] {
  --radius-card: 6px;
  --radius-btn: 4px;
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}
body[data-reduced-motion="true"] *,
body[data-reduced-motion="true"] *::before,
body[data-reduced-motion="true"] *::after {
  animation-duration: 0.001ms !important;
  transition-duration: 0.001ms !important;
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--bg-main);
  color: var(--text-primary);
  font-family: var(--font-main);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
  font-feature-settings: "cv02", "cv03", "cv04", "cv11";
}

/* Skip link for accessibility */
.skip-link {
  position: absolute;
  top: -100px;
  left: 20px;
  background: var(--accent-yellow);
  color: var(--text-dark);
  padding: 12px 20px;
  font-weight: 900;
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  z-index: 9999;
  text-decoration: none;
}
.skip-link:focus {
  top: 20px;
}

/* App Container */
.app-container {
  width: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 16px 40px;
  display: flex;
  flex-direction: column;
  flex: 1;
}

/* ==========================================================================
   HEADER
   ========================================================================== */
.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 0;
  border-bottom: var(--border-width) solid var(--surface-dark);
  margin-bottom: 24px;
}

.logo-group {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  text-decoration: none;
  background: transparent;
  border: none;
  color: inherit;
  font-family: inherit;
}

.logo-badge {
  width: 44px;
  height: 44px;
  background: var(--accent-yellow);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  border-radius: var(--radius-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 900;
  font-size: 24px;
  color: var(--text-dark);
  user-select: none;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
}

.logo-group:hover .logo-badge,
.logo-group:focus-visible .logo-badge {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 var(--border-color);
}

.brand-text {
  display: flex;
  flex-direction: column;
}

.brand-title {
  font-size: 1.6rem;
  font-weight: 900;
  letter-spacing: -0.04em;
  text-transform: uppercase;
  color: var(--text-primary);
  line-height: 1;
}

.brand-tagline {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--text-secondary);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* ==========================================================================
   BUTTONS & CHUNKY CONTROLS
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-family: var(--font-main);
  font-size: 0.95rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.02em;
  padding: 10px 18px;
  border-radius: var(--radius-btn);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  user-select: none;
  text-decoration: none;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-fast);
  white-space: nowrap;
}

.btn:hover {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 var(--border-color);
}

.btn:active,
.btn.pressed {
  transform: translate(3px, 3px);
  box-shadow: var(--shadow-pressed);
}

.btn:focus-visible {
  outline: 3px solid var(--accent-cyan);
  outline-offset: 3px;
}

/* Button Variants */
.btn-primary {
  background-color: var(--accent);
  color: var(--text-dark);
}
.btn-primary:hover {
  filter: brightness(1.05);
}

.btn-secondary {
  background-color: var(--surface);
  color: var(--text-dark);
}
.btn-secondary:hover {
  background-color: #fff;
}

.btn-dark {
  background-color: var(--surface-dark);
  color: var(--text-primary);
  border-color: #3b3b3b;
  box-shadow: 3px 3px 0 #000;
}
.btn-dark:hover {
  background-color: var(--surface-dark-hover);
  border-color: #555;
}

.btn-lime {
  background-color: var(--accent-lime);
  color: var(--text-dark);
}

.btn-pink {
  background-color: var(--accent-pink);
  color: var(--text-dark);
}

.btn-cyan {
  background-color: var(--accent-cyan);
  color: var(--text-dark);
}

.btn-icon-only {
  width: 44px;
  height: 44px;
  padding: 0;
  flex-shrink: 0;
}

.btn-lg {
  font-size: 1.25rem;
  padding: 16px 28px;
  box-shadow: var(--shadow-md);
}
.btn-lg:hover {
  box-shadow: 7px 7px 0 var(--border-color);
}

/* ==========================================================================
   SCREENS & PANELS
   ========================================================================== */
.screen {
  display: none;
  opacity: 0;
  flex-direction: column;
  animation: fadeIn 0.15s ease-out forwards;
}

.screen.active {
  display: flex;
  opacity: 1;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==========================================================================
   SCREEN: HOME
   ========================================================================== */
.hero-section {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  margin: 16px 0 32px;
  gap: 12px;
}

.hero-pill {
  display: inline-block;
  background: var(--surface-dark);
  color: var(--accent-yellow);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  padding: 4px 12px;
  font-size: 0.78rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border-radius: var(--radius-badge);
}

.hero-heading {
  font-size: clamp(2.2rem, 6vw, 4.4rem);
  font-weight: 900;
  line-height: 0.98;
  letter-spacing: -0.04em;
  text-transform: uppercase;
  color: var(--text-primary);
}

.hero-highlight {
  display: inline-block;
  background: var(--accent-yellow);
  color: var(--text-dark);
  padding: 2px 14px;
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  border-radius: var(--radius-badge);
  margin-top: 6px;
  transform: rotate(-1deg);
}

.hero-subtitle {
  font-size: clamp(1rem, 2.5vw, 1.3rem);
  color: var(--text-secondary);
  font-weight: 600;
  max-width: 620px;
  margin-top: 6px;
}

/* Statistics Strip */
.stats-strip {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-bottom: 40px;
}

.stat-card {
  padding: 16px 20px;
  border-radius: var(--radius-card);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.stat-card-yellow {
  background: var(--accent-yellow);
  color: var(--text-dark);
}
.stat-card-lime {
  background: var(--accent-lime);
  color: var(--text-dark);
}
.stat-card-cyan {
  background: var(--accent-cyan);
  color: var(--text-dark);
}

.stat-label {
  font-size: 0.76rem;
  font-weight: 900;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0.85;
}

.stat-value {
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 900;
  line-height: 1.1;
  font-variant-numeric: tabular-nums;
  margin-top: 4px;
}

/* Challenge Modes Section */
.section-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 20px;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  display: flex;
  align-items: center;
  gap: 10px;
}

.section-badge {
  background: var(--accent-pink);
  color: var(--text-dark);
  font-size: 0.75rem;
  padding: 2px 8px;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-badge);
}

.game-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
  margin-bottom: 40px;
}

.game-card {
  border-radius: var(--radius-card);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  padding: 22px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 14px;
  position: relative;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast);
  text-align: left;
  background: var(--surface);
  color: var(--text-dark);
}

.game-card:hover {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 var(--border-color);
}

.game-card:active {
  transform: translate(3px, 3px);
  box-shadow: var(--shadow-pressed);
}

.game-card:focus-visible {
  outline: 3px solid var(--accent-cyan);
  outline-offset: 3px;
}

/* Card Accent Themes */
.game-card[data-mode="quickMath"] { background: var(--accent-yellow); }
.game-card[data-mode="advanced"] { background: var(--accent-purple); color: #fff; }
.game-card[data-mode="sequences"] { background: var(--accent-cyan); }
.game-card[data-mode="compare"] { background: var(--accent-pink); }
.game-card[data-mode="squares"] { background: var(--accent-lime); }
.game-card[data-mode="puzzles"] { background: var(--accent-orange); }
.game-card[data-mode="mixed"] {
  background: var(--surface);
  border: var(--border-width) solid var(--border-color);
}

.game-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.game-icon-box {
  width: 50px;
  height: 50px;
  background: #fff;
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: 2px 2px 0 var(--border-color);
  border-radius: var(--radius-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  font-weight: 900;
}

.game-card-title {
  font-size: 1.35rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  line-height: 1.1;
}

.game-card-desc {
  font-size: 0.9rem;
  font-weight: 600;
  line-height: 1.4;
  opacity: 0.9;
  flex: 1;
}

.game-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  font-weight: 900;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-top: 2px solid rgba(0, 0, 0, 0.15);
  padding-top: 10px;
}

/* ==========================================================================
   SCREEN: GAME CONFIGURATION
   ========================================================================== */
.config-container {
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.config-card {
  background: var(--surface);
  color: var(--text-dark);
  border-radius: var(--radius-card);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-lg);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.config-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: var(--border-width) solid var(--border-color);
  padding-bottom: 18px;
}

.config-title-group {
  display: flex;
  flex-direction: column;
}

.config-subtitle {
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: #666;
}

.config-game-title {
  font-size: 1.8rem;
  font-weight: 900;
  text-transform: uppercase;
}

.config-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.config-label {
  font-size: 0.9rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Difficulty Selector Blocks */
.diff-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 12px;
}

.diff-card {
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--radius-btn);
  background: #fff;
  padding: 14px;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  gap: 4px;
  transition: transform var(--transition-fast), background-color var(--transition-fast);
  text-align: left;
}

.diff-card:hover {
  transform: translate(-1px, -1px);
}

.diff-card.selected {
  background: var(--accent-yellow);
  box-shadow: var(--shadow-sm);
  outline: 2px solid var(--border-color);
}

.diff-card-title {
  font-size: 1rem;
  font-weight: 900;
  text-transform: uppercase;
}

.diff-card-range {
  font-size: 0.78rem;
  font-weight: 700;
  color: #444;
}

/* Chunky Option Pills (Question count & Timer) */
.options-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.option-pill {
  flex: 1;
  min-width: 60px;
  text-align: center;
  padding: 10px 14px;
  background: #fff;
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--radius-btn);
  box-shadow: var(--shadow-sm);
  font-weight: 800;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform var(--transition-fast), background-color var(--transition-fast);
}

.option-pill.selected {
  background: var(--accent-lime);
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 var(--border-color);
}

/* Operations Toggle for Quick Math */
.ops-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.op-toggle {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 14px;
  background: #fff;
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--radius-btn);
  box-shadow: var(--shadow-sm);
  font-weight: 800;
  cursor: pointer;
  user-select: none;
}

.op-toggle.active {
  background: var(--accent-cyan);
}

/* ==========================================================================
   SCREEN: GAMEPLAY
   ========================================================================== */
.gameplay-wrapper {
  max-width: 820px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.gameplay-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.gameplay-title-badge {
  background: var(--surface-dark);
  color: var(--text-primary);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  padding: 8px 16px;
  border-radius: var(--radius-btn);
  font-size: 0.95rem;
  font-weight: 900;
  text-transform: uppercase;
}

/* Timer & Progress Bar */
.timer-container {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.timer-box {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  border-radius: var(--radius-btn);
  padding: 10px 18px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-weight: 900;
  font-size: 1.3rem;
  font-variant-numeric: tabular-nums;
  transition: background-color 0.2s, color 0.2s;
}

.timer-box.timer-warning {
  background: var(--error);
  color: #fff;
  animation: pulseWarning 0.5s infinite alternate;
}

@keyframes pulseWarning {
  from { transform: scale(1); }
  to { transform: scale(1.02); }
}

.progress-track {
  width: 100%;
  height: 14px;
  background: var(--surface-dark);
  border: var(--border-width) solid var(--border-color);
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 2px 2px 0 var(--border-color);
}

.progress-fill {
  height: 100%;
  width: 100%;
  background: var(--accent-lime);
  transition: width 0.05s linear;
}

.timer-warning .progress-fill,
.progress-fill.warning {
  background: var(--error);
}

/* Question Metadata Banner */
.meta-banner {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.meta-item {
  background: var(--surface-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  border-radius: var(--radius-btn);
  padding: 8px 12px;
  text-align: center;
}

.meta-item-label {
  font-size: 0.72rem;
  font-weight: 800;
  text-transform: uppercase;
  color: var(--text-secondary);
}

.meta-item-value {
  font-size: 1.25rem;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  color: var(--accent-yellow);
}

/* Question Card */
.question-card {
  background: var(--surface);
  color: var(--text-dark);
  border-radius: var(--radius-card);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-lg);
  padding: 36px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: 180px;
  position: relative;
  text-align: center;
}

.category-tag {
  position: absolute;
  top: 12px;
  left: 14px;
  background: var(--accent-pink);
  color: var(--text-dark);
  font-size: 0.75rem;
  font-weight: 900;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 8px;
  border: 2px solid var(--border-color);
  border-radius: var(--radius-badge);
}

.question-expression {
  font-size: clamp(2rem, 5.5vw, 3.5rem);
  font-weight: 900;
  letter-spacing: -0.03em;
  font-variant-numeric: tabular-nums;
  line-height: 1.2;
}

/* Math Puzzle 4-Row Box Layout */
.puzzle-grid-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  width: 100%;
  max-width: 340px;
  margin: 12px auto;
}

.puzzle-box-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  width: 100%;
}

.puzzle-cell {
  width: 54px;
  height: 54px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: #ffffff;
  color: var(--text-dark, #111111);
  border: var(--border-width, 3px) solid var(--border-color, #050505);
  box-shadow: 3px 3px 0 var(--border-color, #050505);
  border-radius: var(--radius-btn, 8px);
  font-size: 1.45rem;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  user-select: none;
}

.puzzle-cell.puzzle-result {
  background: var(--surface-muted, #E6E0D5);
  font-weight: 800;
}

.puzzle-cell.puzzle-target {
  background: var(--accent-yellow, #FFE66D);
  color: var(--text-dark, #111111);
  border-width: 3.5px;
  font-size: 1.8rem;
  font-weight: 900;
  box-shadow: 3.5px 3.5px 0 var(--border-color, #050505);
  animation: pulse-target 1.8s infinite ease-in-out;
}

@keyframes pulse-target {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.06); }
}

.puzzle-arrow {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--text-dark, #111111);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 4px;
  user-select: none;
}

@media (max-width: 480px) {
  .puzzle-grid-container {
    gap: 8px;
    margin: 8px auto;
  }
  .puzzle-box-row {
    gap: 7px;
  }
  .puzzle-cell {
    width: 46px;
    height: 46px;
    font-size: 1.25rem;
    box-shadow: 2px 2px 0 var(--border-color, #050505);
  }
  .puzzle-cell.puzzle-target {
    font-size: 1.5rem;
    box-shadow: 2.5px 2.5px 0 var(--border-color, #050505);
  }
  .puzzle-arrow {
    font-size: 1.15rem;
    padding: 0 2px;
  }
}

.puzzle-op {
  font-size: 1.3rem;
  font-weight: 900;
  color: var(--text-dark);
}

/* Answers Grid */
.answers-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
}

.answer-btn {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  border-radius: var(--radius-card);
  padding: 18px 20px;
  font-size: clamp(1.2rem, 3vw, 1.8rem);
  font-weight: 900;
  cursor: pointer;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background-color var(--transition-fast);
  user-select: none;
  font-variant-numeric: tabular-nums;
}

.answer-btn:hover:not(:disabled) {
  transform: translate(-2px, -2px);
  box-shadow: 7px 7px 0 var(--border-color);
  background: #fff;
}

.answer-btn:active:not(:disabled) {
  transform: translate(3px, 3px);
  box-shadow: var(--shadow-pressed);
}

.answer-btn:disabled {
  cursor: default;
}

.key-badge {
  position: absolute;
  top: 8px;
  left: 8px;
  background: var(--surface-dark);
  color: var(--text-primary);
  font-size: 0.72rem;
  font-weight: 800;
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* Answer Selected States */
.answer-btn.ans-correct {
  background: var(--success) !important;
  color: var(--text-dark) !important;
  border-color: #050505 !important;
}

.answer-btn.ans-wrong {
  background: var(--error) !important;
  color: #fff !important;
  border-color: #050505 !important;
}

/* Compare Mode: 3 Chunky Options */
.answers-grid.compare-layout {
  grid-template-columns: repeat(3, 1fr);
}

/* Feedback Banner */
.feedback-banner {
  min-height: 54px;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 10px 16px;
  border-radius: var(--radius-btn);
  font-size: 1.15rem;
  font-weight: 900;
  text-transform: uppercase;
  border: var(--border-width) solid transparent;
  opacity: 0;
  transition: opacity 0.15s ease-in-out;
}

.feedback-banner.show-correct {
  opacity: 1;
  background: var(--accent-lime);
  color: var(--text-dark);
  border-color: var(--border-color);
  box-shadow: var(--shadow-sm);
}

.feedback-banner.show-wrong {
  opacity: 1;
  background: var(--error);
  color: #fff;
  border-color: var(--border-color);
  box-shadow: var(--shadow-sm);
}

/* ==========================================================================
   SCREEN: RESULTS
   ========================================================================== */
.results-container {
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.results-hero-card {
  background: var(--accent-yellow);
  color: var(--text-dark);
  border-radius: var(--radius-card);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-lg);
  padding: 32px 24px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.results-super-title {
  font-size: 0.9rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.results-score {
  font-size: clamp(3rem, 8vw, 5rem);
  font-weight: 900;
  line-height: 1;
  letter-spacing: -0.04em;
}

.results-score-label {
  font-size: 1.1rem;
  font-weight: 900;
  text-transform: uppercase;
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.result-stat-box {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  border-radius: var(--radius-btn);
  padding: 16px;
  text-align: center;
}

.result-stat-label {
  font-size: 0.72rem;
  font-weight: 900;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #555;
}

.result-stat-val {
  font-size: 1.8rem;
  font-weight: 900;
  font-variant-numeric: tabular-nums;
  margin-top: 4px;
}

.results-actions {
  display: flex;
  flex-direction: column;
  gap: 12px;
  width: 100%;
}

.results-actions .btn {
  width: 100%;
  min-width: 0;
  white-space: normal;
  word-break: keep-all;
  text-align: center;
  font-size: 1.08rem;
  padding: 14px 18px;
  min-height: 52px;
}

@media (min-width: 641px) {
  .results-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 14px;
  }

  .results-actions .btn {
    font-size: 1.15rem;
    padding: 16px 24px;
  }

  .results-actions #btn-results-home {
    grid-column: span 2;
  }

  .results-actions.no-mistakes {
    grid-template-columns: 1fr 1fr;
  }

  .results-actions.no-mistakes #btn-results-home {
    grid-column: auto;
  }
}

/* ==========================================================================
   SCREEN: STATISTICS DASHBOARD & CHARTS
   ========================================================================== */
.stats-container {
  max-width: 900px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.chart-card {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  border-radius: var(--radius-card);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.chart-title {
  font-size: 1.15rem;
  font-weight: 900;
  text-transform: uppercase;
  letter-spacing: -0.01em;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Neo-Brutalist Category Accuracy Bars */
.category-bars {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.category-bar-row {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.category-bar-meta {
  display: flex;
  justify-content: space-between;
  font-size: 0.85rem;
  font-weight: 800;
  text-transform: uppercase;
}

.category-bar-track {
  width: 100%;
  height: 20px;
  background: var(--surface-muted);
  border: 2px solid var(--border-color);
  border-radius: 4px;
  overflow: hidden;
  box-shadow: 2px 2px 0 var(--border-color);
}

.category-bar-fill {
  height: 100%;
  background: var(--accent-yellow);
  transition: width 0.4s ease-out;
}

/* SVG Sparkline / Trend Chart */
.trend-chart-box {
  width: 100%;
  height: 180px;
  background: var(--surface-muted);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-btn);
  box-shadow: 2px 2px 0 var(--border-color);
  position: relative;
  overflow: hidden;
}

.trend-svg {
  width: 100%;
  height: 100%;
  display: block;
}

/* ==========================================================================
   SCREEN: SESSION HISTORY
   ========================================================================== */
.history-container {
  max-width: 900px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.filter-bar {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
}

.select-filter {
  padding: 8px 14px;
  background: var(--surface);
  color: var(--text-dark);
  font-family: inherit;
  font-weight: 800;
  font-size: 0.9rem;
  border: var(--border-width) solid var(--border-color);
  border-radius: var(--radius-btn);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.history-item {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-sm);
  border-radius: var(--radius-btn);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  transition: transform var(--transition-fast);
}

.history-item:hover {
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 var(--border-color);
}

.history-main-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.history-game-name {
  font-size: 1.1rem;
  font-weight: 900;
  text-transform: uppercase;
}

.history-date {
  font-size: 0.76rem;
  font-weight: 700;
  color: #666;
}

.history-metrics {
  display: flex;
  align-items: center;
  gap: 20px;
  text-align: right;
}

.history-score-val {
  font-size: 1.4rem;
  font-weight: 900;
  color: var(--text-dark);
}

/* ==========================================================================
   SCREEN: SETTINGS
   ========================================================================== */
.settings-container {
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.settings-card {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  border-radius: var(--radius-card);
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.settings-section-title {
  font-size: 1.25rem;
  font-weight: 900;
  text-transform: uppercase;
  border-bottom: 2px solid var(--border-color);
  padding-bottom: 10px;
}

.setting-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.setting-info {
  display: flex;
  flex-direction: column;
}

.setting-title {
  font-size: 1rem;
  font-weight: 900;
  text-transform: uppercase;
}

.setting-desc {
  font-size: 0.82rem;
  font-weight: 600;
  color: #555;
}

/* Accent Color Swatches */
.swatch-group {
  display: flex;
  gap: 8px;
}

.color-swatch {
  width: 32px;
  height: 32px;
  border-radius: 6px;
  border: 2px solid var(--border-color);
  box-shadow: 2px 2px 0 var(--border-color);
  cursor: pointer;
  transition: transform var(--transition-fast);
}

.color-swatch.active {
  transform: scale(1.15) translate(-1px, -1px);
  outline: 2px solid #000;
}

/* Toggle Switch Brutalist */
.switch {
  position: relative;
  display: inline-block;
  width: 54px;
  height: 30px;
  flex-shrink: 0;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--surface-muted);
  border: 2px solid var(--border-color);
  border-radius: 6px;
  box-shadow: 2px 2px 0 var(--border-color);
  transition: background-color var(--transition-fast);
}

.slider::before {
  position: absolute;
  content: "";
  height: 18px;
  width: 18px;
  left: 3px;
  bottom: 3px;
  background-color: var(--border-color);
  border-radius: 3px;
  transition: transform var(--transition-fast);
}

input:checked + .slider {
  background-color: var(--accent-lime);
}

input:checked + .slider::before {
  transform: translateX(24px);
}

/* ==========================================================================
   MODALS
   ========================================================================== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.75);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.15s ease-out;
}

.modal-overlay.active {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-lg);
  border-radius: var(--radius-card);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  transform: translateY(10px);
  transition: transform 0.15s ease-out;
}

.modal-overlay.active .modal-card {
  transform: translateY(0);
}

.modal-header {
  padding: 18px 24px;
  border-bottom: var(--border-width) solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.modal-title {
  font-size: 1.35rem;
  font-weight: 900;
  text-transform: uppercase;
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.modal-footer {
  padding: 18px 24px;
  border-top: var(--border-width) solid var(--border-color);
  display: flex;
  justify-content: flex-end;
  gap: 12px;
}

/* Mistake Review Item */
.mistake-card {
  border: 2px solid var(--border-color);
  border-radius: var(--radius-btn);
  background: #fff;
  padding: 14px;
  box-shadow: 2px 2px 0 var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.mistake-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.78rem;
  font-weight: 800;
  color: #666;
  text-transform: uppercase;
}

.mistake-expression {
  font-size: 1.25rem;
  font-weight: 900;
}

.mistake-details {
  display: flex;
  gap: 16px;
  font-size: 0.88rem;
  font-weight: 800;
}

.mistake-ans-wrong {
  color: var(--error);
}

.mistake-ans-correct {
  color: #1e7e34;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.site-footer {
  margin-top: auto;
  padding: 24px 0 10px;
  border-top: var(--border-width) solid var(--surface-dark);
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.footer-stamp {
  display: inline-block;
  background: var(--surface-dark);
  color: var(--accent-yellow);
  padding: 6px 14px;
  border: 2px solid var(--border-color);
  box-shadow: 2px 2px 0 var(--border-color);
  border-radius: var(--radius-badge);
  font-weight: 900;
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.footer-nav {
  display: flex;
  gap: 16px;
  margin-top: 4px;
}

.footer-nav-link {
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 700;
  text-decoration: underline;
  cursor: pointer;
  background: none;
  border: none;
}
.footer-nav-link:hover {
  color: var(--accent-yellow);
}

/* Empty state banner */
.empty-state {
  padding: 40px 20px;
  text-align: center;
  border: 2px dashed #444;
  border-radius: var(--radius-card);
  color: var(--text-secondary);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
}

/* ==========================================================================
   PWA INSTALLATION COMPONENTS
   ========================================================================== */
.btn-header-install {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background-color: var(--accent);
  color: var(--text-dark);
  font-weight: 800;
  border-radius: var(--radius-btn);
  height: 44px;
  padding: 0 14px;
  flex-shrink: 0;
}

.btn-header-install:hover {
  background-color: var(--accent);
  filter: brightness(1.08);
}

.install-banner {
  background: var(--surface);
  color: var(--text-dark);
  border: var(--border-width) solid var(--border-color);
  box-shadow: var(--shadow-md);
  border-radius: var(--radius-card);
  padding: 16px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 28px;
}

.install-banner-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.install-banner-badge {
  width: 44px;
  height: 44px;
  background: var(--accent);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-btn);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--text-dark);
}

.install-banner-text {
  display: flex;
  flex-direction: column;
}

.install-banner-title {
  font-size: 1.05rem;
  font-weight: 900;
  text-transform: uppercase;
  color: var(--text-dark);
  line-height: 1.2;
}

.install-banner-desc {
  font-size: 0.85rem;
  font-weight: 600;
  color: #555;
  margin-top: 2px;
}

/* ==========================================================================
   RESPONSIVE DESIGN (320px to 1440px)
   ========================================================================== */
@media (max-width: 640px) {
  .site-header {
    padding: 12px 0;
  }
  .brand-title {
    font-size: 1.3rem;
  }
  .brand-tagline {
    font-size: 0.65rem;
  }
  .btn-header-install {
    padding: 0;
    width: 44px;
    height: 44px;
    justify-content: center;
  }
  .btn-header-install .btn-install-text {
    display: none;
  }
  .install-banner {
    flex-direction: column;
    align-items: stretch;
    gap: 14px;
  }
  .install-banner .btn {
    width: 100%;
  }
  .stats-strip {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .game-grid {
    grid-template-columns: 1fr;
  }
  .diff-grid {
    grid-template-columns: 1fr;
  }
  .answers-grid {
    grid-template-columns: 1fr;
    gap: 12px;
  }
  .answers-grid.compare-layout {
    grid-template-columns: 1fr;
  }
  .results-grid {
    grid-template-columns: 1fr;
    gap: 10px;
  }
  .results-actions {
    display: flex;
    flex-direction: column;
    gap: 12px;
  }
  .results-actions .btn {
    width: 100%;
    font-size: 1.05rem;
    padding: 14px 16px;
  }
  .btn-lg {
    font-size: 1.05rem;
    padding: 13px 20px;
  }
  .meta-banner {
    grid-template-columns: 1fr 1fr;
  }
  .meta-banner .meta-item:last-child {
    grid-column: span 2;
  }
}