.grid-canvas-container {
    width: 1000px;
    height: 1000px;
    background-image: linear-gradient(#e5e7eb 1px, transparent 1px),
                      linear-gradient(90deg, #e5e7eb 1px, transparent 1px);
    background-size: 10px 10px;
    background-color: #f9fafb;
    border: 1px solid #d1d5db;
    position: relative;
    cursor: pointer;
}

#tooltip {
    position: absolute;
    background: rgba(15, 23, 42, 0.95);
    color: white;
    padding: 8px 12px;
    border-radius: 6px;
    font-size: 12px;
    pointer-events: none;
    z-index: 50;
    display: none;
    white-space: nowrap;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

@keyframes selectPulse {
    0% { box-shadow: 0 0 0 0 rgba(37, 99, 235, 0.35), 0 0 0 0 rgba(6, 182, 212, 0.18); }
    55% { box-shadow: 0 0 0 6px rgba(37, 99, 235, 0.10), 0 0 0 14px rgba(6, 182, 212, 0.00); }
    100% { box-shadow: 0 0 0 0 rgba(37, 99, 235, 0.00), 0 0 0 0 rgba(6, 182, 212, 0.00); }
}

#selection-indicator {
    position: absolute;
    pointer-events: none;
    z-index: 45;
    border-radius: 2px;
    box-sizing: border-box;
    border: 2px solid rgba(37, 99, 235, 0.85);
    background: rgba(37, 99, 235, 0.06);
    animation: selectPulse 1.35s ease-in-out infinite;
}