html, body {
  margin: 0;
  padding: 0;
  background: #061022;
  color: #e5f2e5;
  font-family: Arial, sans-serif;
  height: 100%;
}
body {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
  padding: 12px;
  height: 100vh;
}
#game {
  width: min(94vw, 640px);
  height: auto;
  display: block;
  background: #091018;
  border: 2px solid #2f3e46;
  border-radius: 8px;
  touch-action: none;
  outline: none;
}
.restart-btn {
  margin: 18px auto 0 auto;
  padding: 12px 28px;
  border-radius: 7px;
  font-size: 1.15rem;
  border: 2px solid #489b6b;
  background: #1f2a37;
  color: #22c55e;
  font-family: inherit;
  cursor: pointer;
  box-shadow: 0 2px 10px #2229;
  transition: all 0.18s;
  display: block;
}
.restart-btn:hover {
  background: #243c2f;
  border-color: #70ffb6;
  color: #b9ffe8;
}