I tried Lightning component tutorial on creating expenseTracker.app.When the page load, in Java console it return this error.

Why?Anyone face this error? I click on the top error and here the snippet of error.
GET https://unid-dev-ed.my.salesforce.com/fonts/proximanovasoft-regular.woff ltng$require.Helper.inject @ app.js:3869$A.clientService.initDefs.componentDefs.v.controllerDef.v.actionDefs.v.code @ app.js:14590Action.$runDeprecated$ @ aura_proddebug.js:5489Component$getActionCaller @ aura_proddebug.js:3598(anonymous function) @ aura_proddebug.js:5061$A.$ns$.$Aura$.$run$ @ aura_proddebug.js:11027Event.$fire$ @ aura_proddebug.js:5036Component.$fire$ @ aura_proddebug.js:4517Component @ aura_proddebug.js:3976aura$component @ app.js:7ltng$require @ app.js:3839$A.$ns$.$AuraComponentService$.$createComponentInstance$ @ aura_proddebug.js:8160$A.$ns$.$AuraComponentService$.$newComponentDeprecated$ @ aura_proddebug.js:8117ComponentPriv$$0.$createComponentStack$ @ aura_proddebug.js:3373ComponentPriv$$0.$setupAttributes$ @ aura_proddebug.js:3465ComponentPriv @ aura_proddebug.js:3260Component @ aura_proddebug.js:3973aura$component @ app.js:7aura$application @ app.js:4319$A.$ns$.$AuraComponentService$.$createComponentInstance$ @ aura_proddebug.js:8160$A.$ns$.$AuraComponentService$.$newComponentDeprecated$ @ aura_proddebug.js:8117ComponentPriv$$0.$setupSuper$ @ aura_proddebug.js:3408ComponentPriv @ aura_proddebug.js:3266Component @ aura_proddebug.js:3973aura$component @ app.js:7aura$application @ app.js:4319unid$expenseTracker @ app.js:4472$A.$ns$.$AuraComponentService$.$createComponentInstance$ @ aura_proddebug.js:8160$A.$ns$.$AuraComponentService$.$newComponentDeprecated$ @ aura_proddebug.js:8117$A.$ns$.$AuraClientService$.$init$ @ aura_proddebug.js:7541MetricsService.$instrument$.instance.(anonymous function) @ aura_proddebug.js:10523$A.$ns$.$Aura$.$initPriv$ @ aura_proddebug.js:10927(anonymous function) @ aura_proddebug.js:10906(anonymous function) @ aura_proddebug.js:7614ServerActionsMetricsPlugin.bind.actionHook @ aura_proddebug.js:11654Action.$finishAction$ @ aura_proddebug.js:5611(anonymous function) @ aura_proddebug.js:7153$A.$ns$.$Aura$.$run$ @ aura_proddebug.js:11027$A.$ns$.$AuraClientService$.$singleAction$ @ aura_proddebug.js:7145$A.$ns$.$AuraClientService$.$doActionCallback$ @ aura_proddebug.js:7236(anonymous function) @ aura_proddebug.js:7193$A.$ns$.$Aura$.$run$ @ aura_proddebug.js:11027$A.$ns$.$AuraClientService$.$actionCallback$ @ aura_proddebug.js:7192$A.$ns$.$AuraClientService$.$finishRequest$.requestConfig.callback @ aura_proddebug.js:7294TransportMetricsPlugin.bind.config.callback @ aura_proddebug.js:11593Transport.$request$.request.onreadystatechange @ aura_proddebug.js:1869