style.css
html,
body {
    width: 100%;
    margin: 0px;
    padding: 0px;
    overflow-x: hidden;
}

#navitems {
    margin-left: 800px;
}

#container1 {
    display: flex;
    flex-direction: row;
}

img {
    max-width: 100%;
    max-height: 100%;
}

#heading1 {
    color: white;
}

#heading2 {
    color: white;
}

.box {
    position: relative;
    width: 100%;
}

.image {
    opacity: 1;
    display: block;
    width: 100%;
    height: auto;
    transition: .5s ease;
    backface-visibility: hidden;
}

.middle {
    transition: .5s ease;
    opacity: 0;
    position: absolute;
    top: 50%;
    left: 47%;
    transform: translate(-50%, -50%);
    -ms-transform: translate(-50%, -50%);
    text-align: center;
}

.box:hover .image {
    opacity: 0.3;
}

.box:hover .middle {
    opacity: 1;
}

.butn {
    font-family: 'Exo', sans-serif;
    border: 2px solid black;
    background-color: transparent;
    color: black;
    padding: 10px 28px;
    margin: 5px 5px;
    font-size: 16px;
    cursor: pointer;
    border-radius: 5px;
    width: 105px;
}

.demo:hover {
    background-color: #4CAF50;
    color: white;
}

.github:hover {
    background: #000000;
    color: white;
}

.me {
    border-radius: 200px;
    width: 400px;
    background-color: white;
    opacity: 95%;
}

.nav-text-home {
    font-family: 'Exo', sans-serif;
}

.nav-text-about {
    font-family: 'Exo', sans-serif;
}

.nav-link {
    color: white;
    font-family: 'Exo', sans-serif;
    text-align: center;
}

.nav-pills>li>a:hover {
    background-color: white;
    color: black;
}

.nav-pills>li>a:active {
    background-color: white;
    color: black;
}

.depend {
    border-radius: 50%;
    width: 200px;
    margin-left: 3.5%;
    border-style: solid;
    opacity: 95%;
}

@media(max-width: 569px) and (orientation: landscape) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 3.5%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 1.5em;
        color: floralwhite;
        text-align: center;
    }
}

@media(max-width: 569px) and (orientation: portrait) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 1.2em;
        color: floralwhite;
        text-align: center;
    }
}

@media(min-width: 570px) and (max-width: 700px) and (orientation: landscape) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 10%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 1.5em;
        color: floralwhite;
        text-align: center;
    }
}

@media(min-width: 570px) and (max-width: 700px) and (orientation: portrait) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 5%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 2em;
        color: floralwhite;
        text-align: center;
    }
}

@media(min-width: 701px) and (max-width: 1000px) and (orientation: landscape) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 14.5%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 2em;
        color: floralwhite;
        text-align: center;
        margin-left: 2.5%;
    }
}

@media(min-width: 701px) and (max-width: 1000px) and (min-height: 550px) and (orientation: landscape) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        width: 350px;
        margin-top: -20%;
        margin-left: 2.5%;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 15%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 1.2em;
        color: floralwhite;
        text-align: center;
        width: 400px;
        margin-left: 2.5%;
    }
}

@media(min-width: 701px) and (max-width: 1000px) and (orientation: portrait) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        margin-left: 2.5%;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 15%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 2em;
        color: floralwhite;
        text-align: center;
        margin-left: 2.5%;
    }
}

@media(min-width: 801px) and (max-width: 1000px) and (min-height: 1000px) and (orientation: portrait) {
    .navbar-brand {
        height: 70px;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        margin-left: 2.5%;
        width: 400px;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 15%;
        margin-top: -10%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 1.2em;
        color: floralwhite;
        text-align: center;
        margin-left: 0%;
        width: 400px;
    }
}

@media(min-width: 1000px) and (max-width: 1030px) and (min-height: 1350px) and (orientation: portrait) {
    .navbar-brand {
        height: 70px;
    }
    .navbar-nav {
        margin-left: 50%;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        margin-left: 2.5%;
        width: 400px;
    }
    .me {
        border-radius: 200px;
        width: 400px;
        margin-left: 15%;
        margin-top: -10%;
        background-color: white;
        opacity: 95%;
    }
    .nav-text-about {
        font-size: 1.5em;
        color: floralwhite;
        text-align: center;
        margin-left: 0%;
        width: 500px;
    }
}


/*
Tablet1: landscape
*/

@media(min-width: 1001px) and (max-width: 1025px) and (orientation: landscape) {
    .navbar-brand {
        position: absolute;
        width: 7%;
        left: 5%;
        top: 20%;
        margin: auto;
    }
    .navbar-nav {
        margin-left: 40%;
    }
    .nav-item {
        margin-right: 10%;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        width: 300px;
        margin-left: 30%;
    }
    .nav-text-about {
        font-size: 1.5em;
        color: floralwhite;
        text-align: center;
        width: 600px;
        margin-left: -35%;
    }
}


/*
Tablet2: landscape
*/

@media(min-width: 1026px) and (max-width: 1123px) and (orientation: landscape) {
    .navbar-brand {
        position: absolute;
        width: 7%;
        left: 5%;
        top: 20%;
        margin: auto;
    }
    .navbar-nav {
        margin-left: 45%;
    }
    .nav-item {
        margin-right: 10%;
    }
    .nav-text-home {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        width: 300px;
        margin-left: 50%;
        margin-top: 10%;
    }
    .nav-text-about {
        font-size: 1.5em;
        color: floralwhite;
        text-align: center;
        width: 600px;
        margin-left: -20%;
        margin-top: 10%;
    }
}


/*
Tablet3: landscape
*/

@media(min-width: 1124px) and (max-width: 1441px) and (orientation: landscape) {
    .navbar-brand {
        position: absolute;
        width: 7%;
        left: 5%;
        top: 20%;
        margin: auto;
    }
    .navbar-nav {
        margin-left: 50%;
    }
    .nav-item {
        margin-right: 10%;
    }
    .nav-text-home {
        font-size: 4em;
        color: floralwhite;
        text-align: center;
        width: 400px;
        margin-left: 50%;
        margin-top: 5%;
    }
    .nav-text-about {
        font-size: 2em;
        color: floralwhite;
        text-align: center;
        width: 800px;
        margin-left: -30%;
        margin-top: 5%;
    }
}

@media(min-width: 1442px) and (max-width: 1921px) and (orientation: landscape) {
    .navbar-brand {
        position: absolute;
        width: 7%;
        left: 5%;
        top: 20%;
        margin: auto;
    }
    .navbar-nav {
        margin-left: 70%;
    }
    .nav-item {
        margin-right: 10%;
    }
    .nav-text-home {
        font-size: 5em;
        color: floralwhite;
        text-align: center;
        width: 500px;
        margin-left: 65%;
        margin-top: 5%;
    }
    .nav-text-about {
        font-size: 3em;
        color: floralwhite;
        text-align: center;
        width: 1000px;
        margin-left: 0%;
        margin-top: 5%;
    }
}

@media(min-width: 1060px)and (orientation: portrait) {
    .navbar-brand {
        position: absolute;
        width: 7%;
        left: 5%;
        top: 20%;
        margin: auto;
    }
    .navbar-nav {
        margin-left: 45%;
    }
    .nav-item {
        margin-right: 10%;
    }
    .nav-text-home {
        font-size: 5em;
        color: floralwhite;
        text-align: center;
        width: 600px;
        margin-left: -30%;
        margin-top: 5%;
    }
    .nav-text-about {
        font-size: 1.5em;
        color: floralwhite;
        text-align: center;
        width: 600px;
        margin-left: -30%;
        margin-top: 5%;
    }
}

.demo {
    border-color: #4CAF50;
    color: green;
    margin-left: 15%;
}

.github {
    border-color: #000000;
    color: #000000;
    margin-left: 15%;
}

.depend_info {
    text-align: center;
    font-family: 'Exo', sans-serif;
    font-size: 1.2em;
    color: white;
}

.center {
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 50%;
}