body {
  margin: 0;

  min-height: 100vh;

  display: flex;
  flex-direction: column;
  align-items: center;

  background:
    radial-gradient(
      circle at top,
      #222 0%,
      #111 45%,
      #080808 100%
    );

  color: white;

  font-family:
    Arial,
    sans-serif;

  text-align: center;
}


h1 {
  margin-top: 25px;
  margin-bottom: 5px;

  font-size: 42px;

  letter-spacing: 8px;
}


body > p {
  margin-top: 4px;

  color: #aaa;
}


#gameShell {
  position: relative;

  width: min(800px, 95%);

  margin-top: 15px;
}


#gameCanvas {
  display: block;

  width: 100%;
  height: auto;

  background: #050505;

  border: 1px solid #555;

  border-radius: 12px;

  box-shadow:
    0 20px 60px
    rgba(0, 0, 0, 0.6);
}


/* =========================
   MENU OVERLAY
   ========================= */

.overlay {
  position: absolute;

  inset: 0;

  display: flex;

  align-items: center;
  justify-content: center;

  background:
    rgba(0, 0, 0, 0.72);

  border-radius: 12px;
}


.overlay.hidden {
  display: none;
}


.menuPanel {
  width: min(420px, 85%);

  padding: 30px;

  background:
    rgba(20, 20, 24, 0.96);

  border:
    1px solid
    rgba(255, 255, 255, 0.15);

  border-radius: 16px;

  text-align: center;
}


.menuPanel h2 {
  margin: 0 0 8px;

  font-size: 54px;

  letter-spacing: 8px;
}


.menuPanel p {
  color: #aaa;
}


.menuPanel h3 {
  margin-top: 25px;
}


#pauseOverlay .menuPanel {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

#pauseOverlay h2 {
  margin-bottom: 10px;
}

#pauseVolumeSlider {
  width: 100%;
  cursor: pointer;
}

#finalScore {
  margin: 15px 0 25px;

  font-size: 22px;

  color: #ccc;
}

#gameOverOverlay .menuPanel {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* =========================
   DIFFICULTY
   ========================= */

#difficultyButtons {
  display: flex;

  gap: 10px;

  justify-content: center;

  margin-bottom: 25px;
}


.menuPanel button {
  padding: 10px 18px;

  border:
    1px solid #555;

  border-radius: 8px;

  background: #222;

  color: white;

  font-size: 16px;

  cursor: pointer;

  transition:
    background 0.15s,
    border-color 0.15s,
    transform 0.1s;
}


.menuPanel button:hover {
  background: #333;
}


.menuPanel button:active {
  transform: scale(0.97);
}


.difficultyButton.selected {
  border-color: white;

  background: #444;
}


/* =========================
   VOLUME
   ========================= */

#volumeSlider {
  width: 100%;

  margin-top: 12px;
  margin-bottom: 15px;

  cursor: pointer;
}


#muteButton {
  min-width: 100px;
}


/* =========================
   START BUTTON
   ========================= */

#startButton {
  display: block;

  width: 100%;

  margin-top: 25px;

  padding: 14px;

  font-size: 20px;

  font-weight: bold;
}