body {
    font-family: "Segoe UI", Tahoma, sans-serif;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
    background: radial-gradient(circle at top, #0a0e27, #050812);
    color: #ffffff;
}

/* Game Container */
#game-container {
    text-align: center;
    padding: 25px 30px;
    border-radius: 20px;
    background: rgba(0, 217, 255, 0.05);
    border: 1px solid rgba(0, 217, 255, 0.3);
    backdrop-filter: blur(12px);
    box-shadow: 0 0 40px rgba(0, 217, 255, 0.2);
}

/* Chess Board */
#board {
    display: grid;
    grid-template-columns: repeat(8, 60px);
    grid-template-rows: repeat(8, 60px);
    border-radius: 12px;
    overflow: hidden;
    border: 2px solid rgba(0,217,255,0.6);
    margin: 20px auto;
    box-shadow: 0 0 30px rgba(0,217,255,0.6);
   }

/* Squares */
.square {
    width: 60px;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 40px;
    font-family: "Segoe UI Symbol", Arial, sans-serif;
    cursor: pointer;
    user-select: none;
    transition: background 0.25s ease, transform 0.25s ease, box-shadow 0.25s ease;
    font-weight: 700;
    text-shadow:
    0 0 6px rgba(255,255,255,0.7),
    0 0 12px rgba(0,217,255,0.4);
}

/* Board colors */
.light {
    background-color: #101a40;
}

.dark {
    background-color: #0a0e27;
}

/* Hover */
.square:hover {
    box-shadow: inset 0 0 18px rgba(0,217,255,0.5);
}

/* Moving animation */
.square.moving {
    transform: scale(1.15);
}

/* Selected piece */
.selected {
    background-color: rgba(0,217,255,0.6) !important;
    box-shadow: inset 0 0 25px rgba(0,217,255,1);
}

/* Possible move */
.possible-move {
    background-color: rgba(0,255,156,0.45) !important;
    box-shadow:
        inset 0 0 18px rgba(0,255,156,1),
        0 0 10px rgba(0,255,156,0.8);
}

/* Check state */
.check {
    background-color: rgba(255,0,0,0.5) !important;
    box-shadow: inset 0 0 25px red;
}

/* Checkmate state */
.checkmate {
    background-color: rgba(255,0,0,0.8) !important;
    box-shadow: 0 0 35px red;
    animation: dangerPulse 1s infinite;
}

@keyframes dangerPulse {
    0% { box-shadow: 0 0 10px red; }
    50% { box-shadow: 0 0 40px red; }
    100% { box-shadow: 0 0 10px red; }
}

/* Status text */
#status {
    margin: 15px 0;
    font-size: 18px;
    color: #ffd166;
    text-shadow: 0 0 10px rgba(255,209,102,0.8);
    letter-spacing: 0.5px;
}

/* Buttons */
button {
    margin: 10px;
    padding: 10px 22px;
    font-size: 15px;
    font-weight: 700;
    cursor: pointer;
    border-radius: 50px;
    border: none;
    background: linear-gradient(135deg, #00d9ff, #7c3aed);
    color: #050812;
    box-shadow: 0 0 20px rgba(0,217,255,0.5);
    transition: all 0.3s ease;
}

button:hover {
    transform: translateY(-4px);
    box-shadow: 0 0 35px rgba(0,217,255,0.9);
}

/* AI difficulty select */
#ai-difficulty {
    margin: 10px;
    padding: 6px 12px;
    border-radius: 8px;
    border: 1px solid rgba(0,217,255,0.5);
    background: rgba(0,217,255,0.05);
    color: #00d9ff;
}
/* White Pieces */
.white-piece {
    color: #f2fcff !important;
    text-shadow:
        0 0 4px #00d9ff,
        text-shadow:
    0 0 3px rgba(255,255,255,0.8),
    0 0 8px rgba(0,217,255,0.6);
}

/* Black Pieces */
.black-piece {
    color: #ffd166 !important;
    text-shadow:
        0 0 4px #ffb703,
        0 0 10px rgba(255,183,3,0.9),
        0 0 18px rgba(255,183,3,0.7);
    filter: brightness(0.75);
}