Edit in JSFiddle

.ng-invalid{
    border: 3px solid red;
}
.ng-valid{
    border: 3px solid green;
}
.ng-pristine{
    border-style: solid;
}
.ng-dirty{
    border-style: dashed;
}

<div class="container" data-ng-app="">
    <div>
        <form name="fm" ng-init="name='철수'">
            이름 : <input type="text" ng-model="name" ng-maxlength="true" placeholder="이름" ng-minlength="2" />
            <br/>
            핸드폰 번호 : <input type="text" ng-model="tel" ng-pattern="/^\d{3}-\d{3,4}-\d{4}/" placeholder="Ex? 010-1234-5678" />
        </form>
    </div>
</div>