:root {
  --color-bg: #050711;
  --color-surface: #0b1024;
  --color-surface-elevated: #111936;
  --color-player: #5eebff;
  --color-ai: #ff5edb;
  --color-ball: #f8fbff;
  --color-success: #b8ff6a;
  --color-warning: #ffd166;
  --color-text: #f4f7ff;
  --color-text-secondary: #aab4d6;
  --color-border: rgba(148, 168, 255, 0.25);
  --color-focus: #5eebff;
  --shadow-panel: 0 18px 60px rgba(0, 0, 0, 0.42);
  --glow-player: 0 0 22px rgba(94, 235, 255, 0.38);
  --glow-ai: 0 0 22px rgba(255, 94, 219, 0.32);
  --radius-control: 10px;
  --radius-panel: 16px;
  --radius-arena: 22px;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-6: 24px;
  --space-8: 32px;
  --space-12: 48px;
  --target-min: 44px;
  --control-height-primary: 48px;
  --transition-fast: 100ms ease-out;
  --transition-control: 150ms ease-out;
  --focus-width: 3px;
  --focus-offset: 3px;
  --content-max-width: 1180px;
}

* { box-sizing: border-box; }

html {
  min-width: 320px;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
  margin: 0;
  overflow-x: hidden;
  overflow-anchor: none;
  color: var(--color-text);
  background:
    radial-gradient(circle at 12% 14%, rgba(94, 235, 255, 0.12), transparent 30rem),
    radial-gradient(circle at 88% 32%, rgba(255, 94, 219, 0.10), transparent 32rem),
    var(--color-bg);
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
}

button,
input {
  font: inherit;
}

button,
label {
  -webkit-tap-highlight-color: transparent;
}

.skip-link {
  position: fixed;
  z-index: 20;
  top: var(--space-3);
  left: var(--space-3);
  padding: var(--space-3) var(--space-4);
  color: var(--color-bg);
  background: var(--color-player);
  border-radius: var(--radius-control);
  font-weight: 800;
  transform: translateY(-180%);
}

.skip-link:focus {
  transform: translateY(0);
}

.app-shell {
  width: min(100%, var(--content-max-width));
  margin-inline: auto;
  padding: clamp(16px, 2.5vh, 32px) clamp(16px, 3vw, 48px) var(--space-12);
}

.utility-row {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-6);
}

.eyebrow {
  margin: 0 0 var(--space-1);
  color: var(--color-player);
  font-size: 0.8rem;
  font-weight: 800;
  letter-spacing: 0.15em;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(1.5rem, 1.1rem + 1.8vw, 2.75rem);
  line-height: 1.05;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.objective {
  margin: var(--space-2) 0 0;
  color: var(--color-text-secondary);
}

.objective strong {
  color: var(--color-warning);
}

button {
  min-width: var(--target-min);
  min-height: var(--target-min);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-control);
  color: var(--color-text);
  background: var(--color-surface-elevated);
  cursor: pointer;
  transition: transform var(--transition-control), border-color var(--transition-control), box-shadow var(--transition-control), background-color var(--transition-control);
}

button:hover {
  border-color: var(--color-player);
  transform: translateY(-1px);
}

button:active {
  transform: scale(0.98);
}

:focus-visible {
  outline: var(--focus-width) solid var(--color-focus);
  outline-offset: var(--focus-offset);
}

.sound-toggle {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: 0 var(--space-4);
  font-weight: 750;
}

.sound-icon {
  color: var(--color-success);
  font-size: 1.2rem;
}

.scoreboard {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(150px, 0.8fr) minmax(0, 1fr);
  align-items: stretch;
  gap: var(--space-3);
  margin-block: clamp(16px, 2.5vh, 24px);
}

.score-card,
.match-state {
  display: flex;
  min-width: 0;
  min-height: 82px;
  align-items: center;
  justify-content: center;
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-panel);
  background: rgba(11, 16, 36, 0.88);
  box-shadow: var(--shadow-panel);
}

.score-card {
  gap: clamp(12px, 2.5vw, 32px);
}

.score-card--player {
  border-color: rgba(94, 235, 255, 0.4);
  box-shadow: var(--glow-player);
}

.score-card--computer {
  border-color: rgba(255, 94, 219, 0.4);
  box-shadow: var(--glow-ai);
}

.score-name {
  font-weight: 750;
}

.score-card--player .score-name,
.score-card--player .score-number {
  color: var(--color-player);
}

.score-card--computer .score-name,
.score-card--computer .score-number {
  color: var(--color-ai);
}

.score-number {
  font-size: clamp(2.25rem, 1.5rem + 4vw, 5rem);
  line-height: 0.9;
  font-variant-numeric: tabular-nums;
}

.match-state {
  flex-direction: column;
  text-align: center;
}

.match-state strong {
  font-size: clamp(1.05rem, 0.95rem + 0.7vw, 1.4rem);
}

.match-state span {
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

.match-state .state-label {
  color: var(--color-warning);
  font-weight: 750;
}

.arena-frame {
  position: relative;
  overflow: hidden;
  width: 100%;
  border: 2px solid rgba(148, 168, 255, 0.33);
  border-radius: var(--radius-arena);
  background: var(--color-surface);
  box-shadow: var(--shadow-panel), 0 0 36px rgba(94, 235, 255, 0.1);
}

canvas {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  background:
    linear-gradient(90deg, transparent calc(50% - 1px), rgba(244, 247, 255, 0.22) 50%, transparent calc(50% + 1px)),
    repeating-linear-gradient(0deg, transparent 0 47px, rgba(94, 235, 255, 0.025) 48px),
    repeating-linear-gradient(90deg, transparent 0 47px, rgba(255, 94, 219, 0.025) 48px),
    linear-gradient(135deg, #080d20, #0b1024 48%, #140b20);
}

.result-panel {
  position: absolute;
  z-index: 5;
  inset: 50% auto auto 50%;
  width: min(90%, 440px);
  padding: var(--space-6);
  text-align: center;
  border: 1px solid var(--color-player);
  border-radius: var(--radius-panel);
  background: rgba(5, 7, 17, 0.96);
  box-shadow: var(--glow-player);
  transform: translate(-50%, -50%);
}

.result-panel h2 {
  margin: 0;
  font-size: clamp(1.25rem, 1rem + 1vw, 2rem);
}

.result-actions {
  display: flex;
  gap: var(--space-3);
  justify-content: center;
}

.control-panel {
  display: grid;
  grid-template-columns: minmax(350px, 1.3fr) minmax(190px, 0.7fr) minmax(230px, 1fr);
  gap: var(--space-4);
  align-items: stretch;
  margin-top: var(--space-4);
}

.difficulty-group,
.start-block,
.instructions {
  min-width: 0;
  margin: 0;
  padding: var(--space-4);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-panel);
  background: rgba(17, 25, 54, 0.72);
}

.difficulty-group legend {
  padding: 0 var(--space-2);
  font-weight: 800;
}

.difficulty-summary {
  margin: var(--space-2) 0 var(--space-3);
  color: var(--color-text-secondary);
  font-size: 0.875rem;
}

.difficulty-options {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-2);
}

.difficulty-option {
  position: relative;
  display: flex;
  min-height: var(--target-min);
  align-items: center;
  justify-content: flex-start;
  gap: var(--space-1);
  padding: var(--space-2) calc(var(--space-2) + 8.5ch) var(--space-2) var(--space-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-control);
  color: var(--color-text-secondary);
  background: var(--color-surface);
  cursor: pointer;
}

.difficulty-option:hover {
  border-color: var(--color-player);
}

.difficulty-option:has(input:checked) {
  border-color: var(--color-player);
  color: var(--color-text);
  background: rgba(94, 235, 255, 0.12);
  box-shadow: inset 0 0 0 1px rgba(94, 235, 255, 0.25);
}

.difficulty-option input {
  position: absolute;
  inset: 0;
  opacity: 0;
}

.difficulty-option:has(input:focus-visible) {
  outline: var(--focus-width) solid var(--color-focus);
  outline-offset: var(--focus-offset);
}

.selected-text {
  position: absolute;
  inset-block: 0;
  inset-inline-end: var(--space-2);
  display: flex;
  align-items: center;
  justify-content: flex-end;
  width: 8.5ch;
  text-align: right;
  color: var(--color-success);
  font-size: 0.7rem;
  font-weight: 800;
  text-transform: uppercase;
  pointer-events: none;
}

#difficulty-description,
.start-block p,
.instructions p {
  margin: var(--space-3) 0 0;
  color: var(--color-text-secondary);
  font-size: clamp(0.875rem, 0.82rem + 0.15vw, 0.975rem);
}

.start-block {
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.primary-action,
.secondary-action {
  min-height: var(--control-height-primary);
  padding: var(--space-3) var(--space-6);
  font-weight: 800;
}

.primary-action {
  border-color: var(--color-player);
  color: var(--color-bg);
  background: var(--color-player);
  box-shadow: var(--glow-player);
}

.secondary-action {
  background: transparent;
}

.instructions h2 {
  margin: 0;
  font-size: 1rem;
}

kbd {
  display: inline-block;
  min-width: 1.7em;
  padding: 1px 5px;
  text-align: center;
  color: var(--color-text);
  border: 1px solid var(--color-border);
  border-radius: 5px;
  background: var(--color-surface);
  font: 700 0.82em ui-monospace, monospace;
}

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

@media (max-width: 980px) {
  .utility-row {
    flex-wrap: wrap;
  }

  .control-panel {
    grid-template-columns: minmax(0, 1fr);
  }
}

@media (max-width: 900px) {
  .scoreboard {
    grid-template-columns: 1fr;
  }

  .result-actions {
    flex-direction: column;
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }

  button:hover,
  button:active {
    transform: none;
  }

  .result-panel {
    box-shadow: 0 0 0 1px rgba(94, 235, 255, 0.24);
  }
}
AITEAMEOF

cat > app.js <<'AITEAMEOF'
const soundToggle = document.querySelector('#sound-toggle');
const soundLabel = document.querySelector('#sound-label');
const liveStatus = document.querySelector('#live-status');
const difficultyDescription = document.querySelector('#difficulty-description');
const difficultyInputs = [...document.querySelectorAll('input[name="difficulty"]')];

const difficultyCopy = Object.freeze({
  easy: ['Easy', 'Relaxed', 'gentle reactions for an approachable match'],
  medium: ['Medium', 'Balanced', 'steady reactions and a fair challenge'],
  hard: ['Hard', 'Reactive', 'quick reactions for an intense challenge'],
});

function syncDifficultySelection() {
  for (const option of difficultyInputs) {
    const selectedText = option.closest('label').querySelector('.selected-text');
    selectedText.textContent = option.checked ? 'Selected' : '';
    option.closest('label').toggleAttribute('aria-checked', option.checked);
  }
}

soundToggle.addEventListener('click', () => {
  const soundIsOn = soundToggle.getAttribute('aria-pressed') === 'true';
  const nextState = !soundIsOn;
  soundToggle.setAttribute('aria-pressed', String(nextState));
  soundToggle.setAttribute('aria-label', nextState ? 'Turn sound off' : 'Turn sound on');
  soundLabel.textContent = nextState ? 'Sound On' : 'Sound Off';
  liveStatus.textContent = nextState ? 'Sound on.' : 'Sound off.';
});

for (const input of difficultyInputs) {
  input.addEventListener('change', () => {
    syncDifficultySelection();
    const [name, style, detail] = difficultyCopy[input.value];
    difficultyDescription.innerHTML = `<strong>${name} — ${style}:</strong> ${detail}.`;
    liveStatus.textContent = `${name} difficulty selected.`;
  });
}

syncDifficultySelection();
AITEAMEOF

ls -la index.html styles.css app.js
wc -l index.html styles.css app.js
node --check app.js