html, body {
  margin: 0;
  padding: 0;
  background: #001a33;
  height: 100%;
  font-family: Arial, sans-serif;
  color: white;
  display: flex;
  justify-content: center;
  align-items: flex-start;
}

.game-container {
  position: relative;
  width: 100%;
  max-width: 900px; /* keep canvas centered on desktops */
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
}

/* HUD (Score, Coins, Total Coins) */
#hud {
  display: flex;
  justify-content: center;
  gap: 30px;
  padding: 12px 0;
  font-size: 18px;
  font-weight: bold;
  color: #ffcc00;
  text-shadow: 1px 1px 2px black;
}

/* Game canvas */
#gameCanvas {
  display: block;
  margin: auto;
  border: 3px solid #ffffff;
  border-radius: 10px;
  background: #001a33;
  cursor: none; /* hide cursor while playing */
  max-width: 100%;
  height: auto;
}

/* Watermark container */
#watermark {
  margin-top: 10px;
  font-family: 'Gill Sans', sans-serif;
  font-size: clamp(18px, 4vw, 32px); /* responsive size */
  color: #ffffff;
  opacity: 0.6;
  text-align: center;
}

/* Overlay: fills the screen with semi-transparent bg */
.overlay {
  display: none; /* hidden by default */
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0,0,0,0.6);
  justify-content: center;
  align-items: center;
  z-index: 10;
}

/* Popup box: smaller, centered card */
.popup-box {
  background: #002244;
  padding: 35px 35px;
  border-radius: 10px;
  text-align: center;
  border: 2px solid #ff8800;
  color: white;
  max-width: 320px;
  width: 80%; /* responsive */
}

.popup-box h2 {
  margin-bottom: 15px;
  color: #ffcc00;
}

.popup-box button {
  padding: 10px 20px;
  margin: 8px;
  font-size: 16px;
  border: none;
  border-radius: 8px;
  background-color: #ff8800;
  color: white;
  cursor: pointer;
}

.popup-box button:hover {
  background-color: #e67300;
}