body {

    margin: 0;

    background:
        radial-gradient(circle at top,
        #18263d,
        #090b10);

    overflow: hidden;

    font-family:
        Inter,
        Arial,
        sans-serif;

    color: white;

    display: flex;
    justify-content: center;
    align-items: center;

    min-height: 100vh;
}

.background-glow {

    position: fixed;

    width: 800px;
    height: 800px;

    background:
        radial-gradient(
            rgba(0,255,200,0.15),
            transparent 70%
        );

    filter: blur(80px);

    animation:
        pulse 6s infinite alternate;
}

@keyframes pulse {

    from {
        transform: scale(1);
    }

    to {
        transform: scale(1.2);
    }
}

.app {
    text-align: center;
    z-index: 2;
}

h1 {

    font-size: 56px;

    color: #72ffd2;

    text-shadow:
        0 0 20px rgba(114,255,210,0.5);
}

#board {

    width: 560px;

    max-width: 95vw;

    border-radius: 20px;

    overflow: hidden;

    box-shadow:
        0 0 50px rgba(0,255,200,0.25);
}

.panel {
    margin-top: 20px;
}

button {

    background:
        linear-gradient(
            135deg,
            #00c896,
            #00e6ff
        );

    border: none;

    color: white;

    padding: 14px 28px;

    border-radius: 14px;

    font-size: 16px;

    cursor: pointer;

    transition: 0.2s;
}

button:hover {

    transform: scale(1.05);

    box-shadow:
        0 0 20px rgba(0,255,200,0.4);
}

#status {

    margin-top: 16px;

    opacity: 0.85;
}