Better to use system fonts for web apps as these fonts are optimized for each OS better. Common font-family values that cover the three major OS: macOS, Windows and Linux.
.sans-serif {
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}
.serif {
font-family: "Iowan Old Style", "Apple Garamond", Baskerville, "Times New Roman", "Droid Serif", Times, "Source Serif Pro", serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
}
.monospaced {
font-family: Menlo, Consolas, Monaco, "Liberation Mono", "Lucida Console", monospace;
}