*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:'Poppins',sans-serif;
}

body{
    min-height:100vh;
    display:flex;
    justify-content:center;
    align-items:center;
    background: linear-gradient(135deg,#1d3640,#1b6781,#2c5364);
    color:#fff;
}

.container{
    backdrop-filter: blur(20px);
    background: rgba(255,255,255,0.08);
    border:1px solid rgba(255,255,255,0.2);
    padding:35px;
    border-radius:25px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.4);
    text-align:center;
    width:380px;
}

h1{
    margin-bottom:15px;
    font-weight:600;
    letter-spacing:1px;
}

.mode-select button{
    padding:8px 18px;
    margin:6px;
    border:none;
    border-radius:25px;
    cursor:pointer;
    font-weight:600;
    background: rgba(255,255,255,0.15);
    color:#fff;
    border:1px solid rgba(255,255,255,0.3);
    transition:0.3s;
    backdrop-filter: blur(10px);
}

.mode-select button:hover{
    background: rgba(255,255,255,0.3);
}

.active{
    background: rgba(0,255,255,0.6);
    color:#000;
}

.board{
    display:grid;
    grid-template-columns:repeat(3,90px);
    gap:12px;
    margin:25px auto;
}

.cell{
    width:90px;
    height:90px;
    background: rgba(255,255,255,0.12);
    border-radius:20px;
    display:flex;
    justify-content:center;
    align-items:center;
    font-size:2.2rem;
    font-weight:600;
    cursor:pointer;
    backdrop-filter: blur(10px);
    border:1px solid rgba(255,255,255,0.25);
    transition:0.3s;
}

.cell:hover{
    transform: translateY(-4px);
    background: rgba(255,255,255,0.25);
    box-shadow: 0 8px 20px rgba(0,0,0,0.4);
}

.scoreboard{
    font-size:14px;
    margin-bottom:10px;
    opacity:0.9;
}

button.restart{
    margin-top:10px;
    padding:10px 22px;
    border:none;
    border-radius:25px;
    cursor:pointer;
    font-weight:600;
    background: rgba(255,255,255,0.2);
    color:#fff;
    border:1px solid rgba(255,255,255,0.3);
    backdrop-filter: blur(10px);
    transition:0.3s;
}

button.restart:hover{
    background: rgba(255,255,255,0.35);
    transform: scale(1.05);
}
/* Footer */
footer{
    margin-top:20px;
    font-size:13px;
    opacity:0.8;
}