html,body{
    margin:0;
    padding:0;
    width:100%;
    height:100%;
    font-family:Arial, sans-serif;
    background:#0d0f14;
    color:#e6ecf2;
}

#app{
    position:relative;
    width:100%;
    height:100%;
    overflow:hidden;
}

canvas{
    position:absolute;
    top:0;
    left:0;
    width:100%;
    height:100%;
    display:block;
    z-index:0;
}

.hud{
    position:absolute;
    top:12px;
    left:12px;
    background:rgba(8,10,15,0.85);
    border:1px solid rgba(255,255,255,0.08);
    border-radius:8px;
    padding:12px 14px;
    backdrop-filter:blur(4px);
    box-shadow:0 10px 30px rgba(0,0,0,0.35);
}

.hud h1{
    margin:0 0 6px 0;
    font-size:16px;
    letter-spacing:0.04em;
    text-transform:uppercase;
}

.hud p{
    margin:4px 0;
    font-size:13px;
    line-height:1.4;
    color:#c5cfda;
}

.status{
    position:absolute;
    bottom:12px;
    left:12px;
    background:rgba(15,19,30,0.9);
    border:1px solid rgba(91,156,255,0.35);
    border-radius:6px;
    padding:10px 12px;
    font-size:13px;
    color:#e8f1ff;
    max-width:320px;
    line-height:1.4;
    box-shadow:0 8px 22px rgba(0,0,0,0.35);
    z-index:2;
}

.fallback-board{
    position:absolute;
    inset:0;
    display:grid;
    grid-template-columns:repeat(8,1fr);
    grid-template-rows:repeat(8,1fr);
    z-index:1;
}

.fallback-board .square{
    display:flex;
    align-items:center;
    justify-content:center;
    font-weight:700;
    font-size:clamp(18px, 3vw, 28px);
    user-select:none;
}

.fallback-board .square.light{
    background:#d2d6de;
    color:#0f141f;
}

.fallback-board .square.dark{
    background:#1c2433;
    color:#e6ecf2;
}

.fallback-board .square.selected{
    outline:3px solid #5c8dff;
    outline-offset:-2px;
}

.fallback-board .square.hover{
    box-shadow:inset 0 0 0 3px rgba(255,209,102,0.5);
}