body { 
margin: 0px; 
overflow: hidden; 
touch-action: none;
user-select: none;
}

.arrow { 
position: absolute; 
background: none; 
width: 3em; 
height: 3em; 
}

#uArrow { 
top:0px; 
width: 100%; 
}

#dArrow { 
bottom:0px; 
width: 100%; 
}

#lArrow { 
left:0px; 
height: 100%; 
}

#rArrow { 
right:0px; 
height: 100%; 
}
  #startBtn, #againBtn {
    font-size: clamp(22px, 7vw, 32px);
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 20px 60px;
    font-size: 32px;
    font-weight: bold;
    background: rgb(59, 84, 251);
    border: 4px solid white;
    border-radius: 12px;
    cursor: pointer;
    z-index: 10;
  }
  #startBtn:hover, #againBtn:hover {
    background: rgb(22, 17, 159);
  }
  #againBtn {
    display: none; /* caché au début */
    top: 70%;      /* plus bas, sous le score final */
  }