* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  height: 100%;
  overflow: hidden;
  font-family: 'PT Sans', sans-serif;
  background: #222;
}

.container {
  display: flex;
  flex-direction: column;
  height: 100%;
  max-width: 520px;
  margin: 0 auto;
  background: #1a1a2e;
}

#header {
  display: flex;
  align-items: center;
  padding: 10px 16px;
  background: #16213e;
  color: #fff;
  gap: 12px;
  flex-shrink: 0;
}

#back {
  cursor: pointer;
  font-size: 20px;
  width: 32px;
  text-align: center;
}

#back a {
  color: #fff;
  text-decoration: none;
}

#spanTitle {
  font-size: 18px;
  font-weight: bold;
  flex: 1;
}

#sound {
  cursor: pointer;
  font-size: 18px;
  width: 32px;
  text-align: center;
}

#levelBar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: 8px 16px;
  background: #0f3460;
  color: #fff;
  flex-shrink: 0;
}

#levelBar label {
  font-size: 14px;
  white-space: nowrap;
}

#levelDropdown {
  padding: 4px 8px;
  font-size: 14px;
  border: none;
  border-radius: 4px;
  background: #e94560;
  color: #fff;
  cursor: pointer;
  outline: none;
  font-family: 'PT Sans', sans-serif;
}

#levelDropdown option {
  background: #16213e;
  color: #fff;
}

#resetBtn {
  padding: 4px 12px;
  font-size: 13px;
  border: none;
  border-radius: 4px;
  background: #533483;
  color: #fff;
  cursor: pointer;
  font-family: 'PT Sans', sans-serif;
}

#resetBtn:hover {
  background: #6b4fa0;
}

.content {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

#gameCanvas {
  display: block;
}