.ecg-container {
    position: relative;
    width: 100%;
    height: 250px;
    background: #fff;
    border: 1px solid #ddd;
    overflow: hidden;
    font-family: monospace;
}

.ecg-canvas {
    display: block;
    width: 100%;
    height: 100%;
    background: #fff;
}

/* Medical grid overlay */
.ecg-container::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(#e0e0e0 1px, transparent 1px),
        linear-gradient(90deg, #e0e0e0 1px, transparent 1px);
    background-size: 20px 20px; /* Standard ECG paper: 5mm squares */
    pointer-events: none;
    z-index: 1;
}

.ecg-container::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: 
        linear-gradient(#c0c0c0 1px, transparent 1px),
        linear-gradient(90deg, #c0c0c0 1px, transparent 1px);
    background-size: 100px 100px; /* Larger 5x5 squares */
    pointer-events: none;
    z-index: 2;
}