* { margin: 0; padding: 0; box-sizing: border-box; }
html, body {
  height: 100%;
  background: #0a0a0a;
  color: #fff;
  font-family: "Segoe UI", system-ui, sans-serif;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}
#game {
  background: #000;
  border: 2px solid #fff;
  display: block;
  max-width: 95vw;
  max-height: 95vh;
  touch-action: none; /* drags move paddles, never scroll the page */
}
.overlay {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.85);
  text-align: center;
  gap: 20px;
}
.overlay h1 {
  font-size: clamp(40px, 10vw, 90px);
  letter-spacing: 12px;
  margin-bottom: 10px;
}
.overlay p { opacity: 0.7; max-width: 320px; line-height: 1.5; }
.btn {
  font: inherit;
  font-size: 22px;
  padding: 14px 40px;
  min-width: 240px;
  background: #fff;
  color: #000;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: transform 0.08s, background 0.15s;
}
.btn:hover { background: #ccc; transform: scale(1.04); }
.hidden { display: none; }

/* Pre-game countdown: lighter overlay so the board stays visible behind it */
#countdown { background: rgba(0, 0, 0, 0.5); gap: 30px; pointer-events: none; z-index: 15; }
.count-num {
  font-size: clamp(80px, 20vw, 170px); font-weight: 700; line-height: 1;
  text-shadow: 0 0 34px rgba(255, 255, 255, 0.35);
}
.count-controls { display: flex; gap: 44px; }
.count-controls > div { display: flex; flex-direction: column; align-items: center; gap: 8px; }
.count-controls b { font-size: 13px; letter-spacing: 2px; text-transform: uppercase; opacity: 0.65; font-weight: 700; }
.count-controls span {
  font-size: 22px; font-weight: 600; padding: 8px 18px;
  border: 1px solid rgba(255, 255, 255, 0.45); border-radius: 8px; min-width: 96px;
}
/* countdown number pops on each tick (auto-disabled by reduce-motion) */
.count-num { animation: countPop 0.9s ease both; }
@keyframes countPop { 0% { opacity: 0; transform: scale(1.45); } 22% { opacity: 1; transform: scale(1); } 100% { opacity: 0.92; transform: scale(1); } }

/* On-screen paddle arrows (touch devices only) */
.pong-ctrl {
  position: fixed;
  bottom: 18px;
  display: none;
  flex-direction: column;
  gap: 16px;
  z-index: 20;
}
#ctrl-left { left: 16px; }
#ctrl-right { right: 16px; }
.pbtn {
  width: 76px;
  height: 76px;
  border-radius: 14px;
  border: 2px solid rgba(255, 255, 255, 0.7);
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  font-size: 30px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  touch-action: none;
  user-select: none;
}
.pbtn:active { background: rgba(255, 255, 255, 0.4); }
@media (pointer: coarse) {
  body.playing #ctrl-left { display: flex; }
  body.playing.p2 #ctrl-right { display: flex; }
}

/* Instructions: one sentence per line; show only the relevant control set.
   Desktop (fine pointer) sees keyboard controls; touch devices see the on-screen
   buttons line — never both. */
#controls span { display: block; line-height: 1.7; }
#controls .ctrl-mobile { display: none; }
@media (pointer: coarse) {
  #controls .ctrl-desktop { display: none; }
  #controls .ctrl-mobile { display: block; }
}

/* tasteful entrance + interaction motion (auto-disabled by reduce-motion) */
.overlay:not(.hidden) { animation: ovFade 0.3s ease both; }
.overlay:not(.hidden) h1 { text-shadow: 0 0 22px rgba(255,255,255,0.2); animation: ovUp 0.5s cubic-bezier(0.2,0.8,0.2,1) backwards, titleGlow 3.4s ease-in-out 0.6s infinite; }
.overlay:not(.hidden) p { animation: ovUp 0.5s cubic-bezier(0.2,0.8,0.2,1) 0.08s backwards; }
.overlay:not(.hidden) .btn { animation: ovUp 0.5s cubic-bezier(0.2,0.8,0.2,1) 0.16s backwards; }
.btn:active { transform: scale(0.96); }
@keyframes ovFade { from { opacity: 0; } to { opacity: 1; } }
@keyframes ovUp { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }
@keyframes titleGlow { 0%, 100% { text-shadow: 0 0 18px rgba(255,255,255,0.15); } 50% { text-shadow: 0 0 32px rgba(255,255,255,0.42); } }

/* Accessibility: honor prefers-reduced-motion — neutralize animations,
   transitions, and motion effects (pulse, shake, drop, blink, glows). */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}