style.css

body{
    font-family: 'Baloo Bhai 2', cursive;
    color: white;
    background: url(gym.jpg) no-repeat ;
    background-size: cover;
    margin: 0px;
    padding: 0px;
}
.left{
    /*border: 2px solid red;*/
    display: inline-block;
    top: 26px;
    left: 30px;
    position: absolute;
}
.left img{
    width: 36px;
    filter: invert(100%);
    margin: auto;
    display: block;

}

.mid{
    /*border: 2px solid green;*/
    display: block;
    width: 40%;
    margin: 26px auto;
}

.navbar li{
    display: inline-block;
}

.navbar li a {
    font-family: 'Baloo Bhai 2', cursive;
    color: white;

    text-decoration: none;
    padding: 10px 5px;
    margin: 18px;
}

.navbar li a:hover,.navbar li a:active{
    text-decoration: underline;
    color: rgb(126, 122, 122);
}

.right{
    /*border: 2px solid yellow;*/
    display: inline-block;
    top: 26px;
    right: 23px;
    position: absolute;

    
}
.btn
{
    font-family: 'Baloo Bhai', cursive;
    color: white;
    background-color: black;
    border-radius: 10px;
    cursor: pointer;
    margin: 5px;
    transition: 0.5s;
}
.btn:hover{
background-color: gray;
}

.container{
    font-family: 'Baloo Bhai', cursive;
    border: 2px solid white;
    position: absolute;
    left: 33px;
    border-radius: 10px;
    padding: 25px;
    margin: 100px;
}

.form-group input{
    text-align: center;
    display: block;
    margin: 8px auto;
    border: 2px solid black;
    border-radius: 8px;
    padding: 2px;

}
.container button{
margin: 10px auto;
display: block;
width: 200px;
}