I have a made the design of this website . This is not responsive can anybody correct this website to be responsive for all devices.

<script>
        var navLinks = document.querySelector("#navLinks");
          function showMenu() {
            navLinks.style.right ="0";
          }
          function hideMenu(){
            navLinks.style.right ="-200px";
          }
    </script>

*{
    margin: 0;
    padding: 0;
    font-family: 'Georama', sans-serif;
}

.header{
    min-height:100vh;
    width:100%;
    background-image: linear-gradient(rgba(4,9,30,0.7),rgba(4,9,30,0.7)),url(./Images/banner.png);
    background-position:center ;
    background-size: cover;
    position:relative;
}

nav{
    display:flex;
    padding:2%;
    justify-content: space-between;
    align-items: center;
}
nav img{
    width:150px;
}

.nav-links{
      flex:1;
      text-align:right;
}

.nav-links ul li{
    list-style:none;
    display:inline-block;
    padding:8px 12px;
    position:relative;
}

.nav-links ul li a{
    color:#fff;
    text-decoration:none;
    font-size:13px;
}

.nav-links ul li::after{
    content:'';
    width:0%;
    height:2px;
    background:#f44336;
    display:block;
    margin:auto;
    transition: 0.5s;
}

.nav-links ul li:hover::after{
    width:100%;
}

.text-box{
    width:90%;
    color:#fff;
    position:absolute;
    top:50%;
    left:50%;
    transform: translate(-50%,-50%);
    text-align:center;
}

.text-box h1{
    font-size: 62px;
}

.text-box p{
    margin:10px 0 40px;
    font-size:14px;
    color:#fff;
}

.register{
    display:inline-block;
    text-decoration:none;
    color:#fff;
    border:1px solid #fff;
    padding:12px 34px;
    font-size:13px;
    background:transparent;
    position: relative;
    cursor:pointer;
}

.register:hover{
    border:1px solid #f44336;
    background:#f44336;
    transition: 1s;
}

nav .fa{
    display:none;
}

@media(max-width:700px){
    .text-box h1{
        font-size: 20px;
    }
    .nav-links ul li{ 
        display:block;
    }
    .nav-links{
        position:absolute;
        background:#f44336;
        height:100vh;
        width:200px;
        top:0;
        right:-200px;
        text-align:left;
        z-index: 2;
        transition: 1s;
    }
    
    nav .fa{
        display:block;
        color:#fff;
        margin:10px;
        font-size:22px;
        cursor:pointer;
    }

    .nav-links ul{
        padding:30px;
    }
    .row{
        flex-direction: column;
    }
    .testimonial-col img{
 
        margin-left: 0px;
        margin-right:15px
      }
     
      .eroll h1{
          font-size:24px;
      }
}

/* Course */

.course{
    width:80%;
    margin:auto;
    text-align:center;
    padding-top:100px;
}

h1{
    color:#777;
    font-size:36px;
    font-weight: 300;
    line-height:22px;
    padding:10px;
}

.row{
    margin-top:5%;
    display: flex;
    justify-content:space-between;
}

.course-col{
    flex-basis:31%;
    background:#fff3f3;
    border-radius:10px;
    margin-bottom:5%;
    padding:20px 12px;
    box-sizing:border-box;
    transition:0.5s;
}

h3{
    text-align:center;
    font-weight: 600;
    margin:10px 0;
}

.course-col:hover{
    box-shadow:0 0 20px 0px rgba(0,0,0,0.2);
}
/* Trainings */
.trainings{
    width:80%;
    margin:auto;
    text-align:center;
    padding-top: 50px;
}

.doubts-col{
    flex-basis:32%;
    border-radius:10px;
    margin-bottom:30px;
    position:relative;
    overflow:hidden;
}

.doubts-col img{
    width:100%;
    display:block;
}

.layer{
    background:transparent;
    height:100%;
    width:100%;
    position:absolute;
    top:0;
    left:0;
    transition:0.5s;
}

.layer:hover{
    cursor: pointer;
}

.layer h2{
    width:100%;
    font-weight: 500;
    color:#fff;
    font-size:26px;
    bottom:0;
    left:50%;
    transform:translate(-50%);
    position:absolute;
    transition:0.5s;
}

.layer:hover h3{
    bottom:49%;
    opacity:1;
}

/* Facilities */

.facilities{
    width:80%;
    margin:auto;
    text-align:center;
    padding-top:100px;

}
.facility-col{
  flex-basis:31%;
  border-radius:10px;
  margin-bottom:5%;
  text-align: left;
}

.facility-col img{
    width:100%;
    border-radius:10px;
}

.facility-col p{
    padding:0   
}

.facility-col h3{
    margin-top:16px;
    margin-bottom: 15px;
    text-align:left;
}

/* Testimonials */

.testimonials{
   width:80%;
   margin:auto;
   padding-top: 100px; 
   text-align:center;
} 

.testimonial-col{
   flex-basis:44%;
   border-radius: 10px;
   margin-bottom:5%;
   text-align:left;
   background: #fff3f3;
   padding:25px;
   cursor:pointer;
   display:flex;
}
.testimonial-col img{
  height:40px;
  margin-left: 5px;
  margin-right:30px;
  border-radius:50%;
}

.testimonial-col p{
    padding:0;
}

.testimonial-col h3{
  margin-top:15px;
  text-align:left;
}

/* Enroll */

.enroll{
    margin:100px auto;
    width:80%;
    background-image: linear-gradient(rgba(0,0,0,0.7),rgba(0,0,0,0.7)),url(./Images/banner2.jpg);
    background-position: center;
    background-size: cover;
    border-radius: 10px;
    text-align:center;
    padding:100px 0;
}

.enroll h1{
    color:#fff;
    margin-bottom:40px;
    padding:0;
}

/* footer */
.footer{
    width:100%;
    text-align:center;
    padding:30px 0;
}

.footer h4{
    margin-bottom: 25px;
    margin-top:20px;
    font-weight: 600;
}

.icons .fa{
    color:#f44336;
    margin:0 13px;
    cursor:pointer;
    padding:18px;
}

<script>
        var navLinks = document.querySelector("#navLinks");
          function showMenu() {
            navLinks.style.right ="0";
          }
          function hideMenu(){
            navLinks.style.right ="-200px";
          }
    </script>