resolveFor method
Resolves the active offset for a given layout width.
Uses a mobile-first approach where larger matching breakpoints take precedence.
Implementation
int resolveFor(double width) {
int result = xs ?? 0;
if (width >= BsBreakpoints.sm && sm != null) result = sm!;
if (width >= BsBreakpoints.md && md != null) result = md!;
if (width >= BsBreakpoints.lg && lg != null) result = lg!;
if (width >= BsBreakpoints.xl && xl != null) result = xl!;
if (width >= BsBreakpoints.xxl && xxl != null) result = xxl!;
return result;
}