JSFiddle - React, Tailwind, and code Playground

HTML

<svg width="100" height="100">
    <line class="lineSVG" x1="50" y1="40" x2="50" y2="60" />
    <line class="lineSVG" x1="40" y1="50" x2="60" y2="50" />
</svg>

CSS

.lineSVG {
    stroke-width: 3px;
}

JavaScript

function changeColor(color) {
    var lines = document.getElementsByClassName('lineSVG');
    
    var i;
    for (i = 0; i < lines.length; i++) {
        var line = lines[i];
        line.style['stroke'] = color;
    } // for i
} // changeColor

changeColor("#FF0000"); // rouge
changeColor("#00FF00"); // vert
changeColor("#0000FF"); // bleu