body {
    margin: 0px;
    font-family: 'Roboto Slab', serif;
    background-image: linear-gradient(120deg, #d86c70, #ddb0a0);
}

.navbar {
    margin-bottom: 0;
    border-radius: 0;
    background-color: lightgrey;
    color: #FFF;
    padding: 1% 0;
    font-size: 1.2em;
    border: 0;
}

.navbar-brand {
    float: left;
    min-height: 55px;
    padding: 0 15px 5px;
}

#icon {
    max-width: 100px;
    margin: 1% auto;
}

.container {
    margin: 4% auto;
}

.responsive {
    width: 100%;
    height: auto;
}

.jumbotron {
    margin: 0;
}

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

.navbar-brand img {
    width: 50px;
    height: 50px;
}

h3 {
    color: white;
}

#about {
    font-size-adjust: 20px;
}

p {
    margin-top: 2em;
    margin-bottom: 2em;
}

a #logo {
    background-color: grey;
}

.footer-text {
    color: white;
}

footer .btn {
    border: none;
    font-size: 18px;
    color: #FFF;
    padding: 12px 22px;
    background: #1E90FF;
}

@media screen and (min-width: 200px) and (max-width: 767px) {
    #app {
        margin-left: 60px;
        margin-top: 75px;
        height: 220px;
        width: 140px;
        border: solid 4px black;
    }
    #display {
        padding: 0;
        margin: 0;
        border: solid 1px black;
        height: 40px;
        width: 138px;
        background-color: black;
        color: white;
        font-size: 15px;
    }
    #buttons-area {
        margin-top: 1px;
        padding-left: 12px;
    }
    .buttons {
        padding: 0;
        margin: 0;
        width: 35px;
        height: 35px;
        background-color: white;
        font-size: 15px;
    }
    .special-buttons {
        padding: 0;
        margin: 0;
        width: 35px;
        height: 35px;
        background-color: lightgrey;
        color: blue;
        font-size: 15px;
    }
    #equals {
        padding: 0;
        margin: 0;
        width: 35px;
        height: 35px;
        background-color: skyblue;
        color: black;
        font-size: 15px;
    }
}


@media screen and (min-width: 800px) and (max-width: 1280px){
    #app {
        margin-left: 200px;
        margin-top: 75px;
        height: 608px;
        width: 400px;
        border: solid 4px black;
    }
    #display {
        padding: 0;
        margin: 0;
        border: solid 1px black;
        height: 105px;
        width: 395px;
        background-color: black;
        color: white;
        font-size: 60px;
    }
    #buttons-area {
        margin-top: 1px;
        padding-left: 12px;
    }
    .buttons {
        padding: 0;
        margin: 0;
        width: 99px;
        height: 99px;
        background-color: white;
        font-size: 60px;
    }
    .special-buttons {
        padding: 0;
        margin: 0;
        width: 99px;
        height: 99px;
        background-color: lightgrey;
        color: blue;
        font-size: 60px;
    }
    #equals {
        padding: 0;
        margin: 0;
        width: 99px;
        height: 99px;
        background-color: skyblue;
        color: black;
        font-size: 60px;
    }
}

@media screen and (min-width: 1281px) {
    #app {
        margin-left: 600px;
        margin-top: 75px;
        height: 608px;
        width: 400px;
        border: solid 4px black;
    }
    #display {
        padding: 0;
        margin: 0;
        border: solid 1px black;
        height: 105px;
        width: 395px;
        background-color: black;
        color: white;
        font-size: 60px;
    }
    #buttons-area {
        margin-top: 1px;
        padding-left: 12px;
    }
    .buttons {
        padding: 0;
        margin: 0;
        width: 99px;
        height: 99px;
        background-color: white;
        font-size: 60px;
    }
    .special-buttons {
        padding: 0;
        margin: 0;
        width: 99px;
        height: 99px;
        background-color: lightgrey;
        color: blue;
        font-size: 60px;
    }
    #equals {
        padding: 0;
        margin: 0;
        width: 99px;
        height: 99px;
        background-color: skyblue;
        color: black;
        font-size: 60px;
    }
}