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

body{
    min-height:100vh;
    display:flex;
    justify-content:center;
    align-items:center;
    background:#f5f5f5;
    font-family:Arial, Helvetica, sans-serif;
    padding:1rem;
}

body{

    transition:background 0.2s;
}
   /* MAIN CARD */

.blink{
    width:100%;
    max-width:500px;
    background:azure;
    border:2px solid black;
    border-radius:2rem;
    padding:1.5rem;
    text-align:center;
}

   /* TITLE */

h1{
    font-size:3rem;
    margin-bottom:1rem;
}

p{
    font-size:1.2rem;
    font-weight:500;
    margin-bottom:1.5rem;
}


   /* GAME CONTAINER */

.container{
    position:relative;
    width:100%;
    aspect-ratio:1/1;
    max-width:350px;
    margin:auto;
    display:grid;
    grid-template-columns:1fr 1fr;
    gap:12px;
}


   /* BUTTONS */

.btn{
     width:100%;
    height:100%;
    cursor:pointer;
    opacity:0.9;
    transition:0.15s ease;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
    user-select: none;
}


/* COLORS */

.green{
    background:#2ecc71;
    border-top-left-radius:100%;
}

.red{
    background:#e74c3c;
    border-top-right-radius:100%;
}

.yellow{
    background:#f1c40f;
    border-bottom-left-radius:100%;
}

.blue{
    background:#3498db;
    border-bottom-right-radius:100%;
}

   /* CENTER CIRCLE */

.center{
    position:absolute;
    top:50%;
    left:50%;
    transform:translate(-50%,-50%);
    width:45%;
    height:45%;
    background:azure;
    border-radius:50%;
    display:flex;
    justify-content:center;
    align-items:center;
    flex-direction:column;
    font-weight:bold;
    text-align:center;
    box-shadow:0 0 10px rgba(0,0,0,0.2);
}


.center span{
    font-size:1.3rem;
}


#score{
    font-size:2rem;
    margin-top:0.4rem;
}

   /* BUTTON FLASH */

.game-style{
    opacity:1;
    transform:scale(0.96);
    filter:brightness(1.2);
    box-shadow:0 0 15px rgba(0,0,0,0.4);
}


   /* GAME OVER FLASH */

body.red{
    background:#ff6b6b;
}

   /* MOBILE */
@media(max-width:500px){

    .blink{

        padding:1rem;
        border-radius:2rem;
    }

    h1{

        font-size:2.2rem;
    }

    p{

        font-size:1rem;
    }

    .container{

        max-width:300px;
    }

    .center span{

        font-size:1rem;
    }

    #score{

        font-size:1.5rem;
    }
}