@keyframes spin {
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    background: #343444;
    overflow: hidden;
    font-family: Arial, sans-serif;
}

#gameContainer, canvas {
    width: 100%;
    height: 100%;
    display: block;
}

#loader {
    position: absolute;
    top: 0;
    width: 100%;
    height: 100%;
    background: #343444;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    container-type: inline-size;
}

#circle {
    width: 48px;
    height: 48px;
    border-radius: 50%;
      
    border: 5px solid white;
    border-top: 5px solid red;
      
    animation: spin 1s linear infinite;
}