parse static method
Implementation
static CSSBorder? parse(String? value) {
if (value == null) return null;
var match = pattern.firstMatch(value);
if (match == null) return null;
var sizeStr = match.group(1);
var styleStr = match.group(2);
var colorStr = match.group(3);
var size = CSSLength.parse(sizeStr);
var style = parseCSSBorderStyle(styleStr);
var color = CSSColor.parse(colorStr);
return CSSBorder(size, style, color);
}