body {
    margin: 0;
    padding: 0;
    background-color: #1a3b3b;
    font-family: Arial, Helvetica, sans-serif;
}

#loading {
    position: fixed;
    width: 100%;
    height: 100vh;
    background: #1a3b3b;
    z-index: 99999;
    text-align: center;
}

#loading img {
    position: relative;
    width: 300px;
    height: 300px;
    margin-top: 230px;
}

nav {
    width: 100%;
    line-height: 80px;
}

.open-menu ul {
    float: right;
    margin-top: -70px;
}

.open-menu ul li {
    display: inline-block;
    line-height: 30px;
    margin-right: 40px;
    padding: 10px;
}

.open-menu ul li a {
    text-decoration: none;
    color: #FFF;
    opacity: .8;
}

.logo {
    width: 260px;
    height: 80px;
    margin-top: 10px;
}

.logo img {
    width: 100%;
    height: 100%;
}

nav ul li a:hover,
nav ul li a:active,
ul li a:focus {
    color: #07f7f0;
    text-decoration: none;
}

.active a {
    color: #07f7f0 !important;
}

label div {
    width: 30px;
    height: 5px;
    background-color: white;
    margin-top: 5px;
}

label {
    position: relative;
    float: right;
    margin-top: 30px;
    margin-right: 20px;
    display: none;
}

.cros-btn .l-1 {}

<!----------------------------------------nav-------------------->.app-text {
    padding: 10px;
    float: left;
    position: relative;
}

.app-text h1 {
    color: #FFF;
    margin-top: 135px;
    font-size: 40px;
    font-weight: bold;
    margin-bottom: 20px;
}

.app-text p {
    color: #fff;
    font-size: 15px;
    opacity: .8;
}

.side-img {
    position: relative;
    width: 500px;
    height: 400px;
    margin-top: 130px;
    padding: 10px;
    margin-bottom: 30px;
}

.side-img img {
    width: 100%;
    height: 100%;
}

.button {
    margin-top: -150px;
}

.btn-1 {
    position: relative;
    padding: 10px 20px;
    background-color: #5659e1;
    border-radius: 30px;
    color: #fff;
    text-decoration: none;
}

.btnnnn-1 a<!-------------impo-------------> {
    padding: 10px 20px;
    background-color: #5659e1;
    border-radius: 30px;
    color: #fff;
}

.btn-1:hover {
    text-decoration: none;
    color: #fff;
}

.btn-1:focus {
    border: none;
}

footer {
    width: 100%;
    height: 40px;
    position: absolute;
    bottom: 0;
    margin-bottom: -50px;
}

footer h3 {
    text-align: center;
    font-size: 13px;
    padding-top: 20px;
    opacity: .8;
    color: #fff;
    background-color: transparent;
}

<!-------------------------------------------------------responceve---------------------------->