* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
html{
    font-size: 16px;
    height: 45px;
}

body {
    font-family: Helvetica, poppins,Time New Roman;
}

header {
    position: fixed;
    width: 100%;
    height: 50px;
    top: 0;
    left: 0;
    background: #fff;
    box-shadow: 0px 0px 4px rgba(0,0,0,.4);
    color: #212121;
    padding: 0 2rem;
    z-index: 100;
}

nav {
    width: 100%;
    height: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 2rem;
}
.logo{
    width: 45px;
    height: 45px;
}
.logo img{
    width: 145px;
    height: 45px;
}
.toggle {
    display: none;
}
.ouvrir{
    width: 45px;
    height: 45px;
}
.fermer{
    width: 45px;
    height: 45px;
}
.menu {
    display: flex;
    justify-content: space-between;
    align-items: center;
    list-style: none;
    width: 80%;
    color: #000;
    font-size: 16px;
    font-weight: bold;
}
.menu-item
{
    color: #000;
    font-size: 15px;
    font-weight: bold; 
}
.menu li a {
    color: #000;
    font-size: 15px;
    font-weight: bold;
    text-decoration: none;
}

li a.btn {
    border: 0;
    background: #268aff;
    font-size: 0.7em;
    padding: 0.5rem 1rem;
    border-radius: 20px;
    color: #fff;
}

li a.btn .btn-secondary {
    background: transparent;
    border: 2px solid #268aff;
    color: #fff;
}
.menu .menu-item ul
{
    position: absolute;
    visibility: hidden;
    z-index: 20;
    opacity: 0;
    text-align: left;
    list-style: none;
}
.menu .menu-item:hover ul 
{
    font-size: 16px;
    font-weight: bold;
    list-style: none;
    color: orange;
    background-color: #ffffff;
    visibility: visible;
    transition: .3s;
    opacity:1;
    text-align: left;
}
.menu .menu-item ul li a
{
    width: 170px;
    height: 45px;
    background-color: #ffffff;
    color:#212121;
    top: 10px;
    padding: 10px;
    position: relative;
    font-size: 16px;
    display: block;
    border-bottom: 1px solid rgba(0,0,0,.1);
}
.menu .menu-item ul li a:hover
{
    width: 170px;
    height: 45px;
    background-color: #268aff;
    color:#fff;
    top: 10px;
    padding: 10px;
    position: relative;
    font-size: 16px;
    display: block;
    border-bottom: 1px solid rgba(0,0,0,.1);
}
@media all and (max-width: 991px) {

    header {
          position: fixed;
        background: #ffffff;
        z-index: 100;

    }

    .toggle {
        display: block;
        font-size: 2rem;
        cursor: pointer;
        position: relative;
        z-index: 20;
    }

    .logo {
        position: relative;
        z-index: 20;
        margin-left:-30px;
    }
    .logo img{
         width: 145px;
         height: 45px;
        
    }
    .ouvrir {
        display: block;
    }

    .fermer {
        display: none;
    }

    .open .ouvrir {
        display: none;
    }

    .open .fermer {
        display: block;
    }

    .menu {
        position: absolute;
        top: 0;
        left: 0;
        width: 100%;
        height: 100vh;
        background: #000;
        flex-direction: column;
        padding: 2rem;
        justify-content: space-around;
        transform: translateX(-100%);
        transition: transform 1s;
        background: linear-gradient(rgba(0,0,0,.6),rgba(0,0,0,.6)),url(../image/fond4.jpg);
        background-repeat: no-repeat;
        background-position: center;
        background-size: cover;
    }
    li a.btn .btn-secondary {
    background: transparent;
    border: 2px solid #268aff;
    color: #fff;
    margin-top: 30px;
    }
    .menu li a {
        font-size: 20px;
        color: #fff;
    }
    li a.btn {
        border: 0;
        background: #268aff;
        font-size: 1rem;
        padding: 0.5rem 1rem;
        border-radius: 10px;
        color: #fff;
    }
    .btn {
        border-radius: 5px;
        font-size: 20px;
    }

    .open .menu {
        transform: translateX(0);
    }
.menu .menu-item{
        font-size: 20px;
        color: #fff;
        margin: 10px;
    }
.menu .menu-item:hover ul 
{
    font-size: 16px;
    font-weight: bold;
    list-style: none;
    background-color: #ffffff;
    visibility: visible;
    transition: .3s;
    opacity:1;
    text-align: left;
}
.menu .menu-item ul li a
{
    width: 170px;
    height: 45px;
    background-color: #ffffff;
    color:#212121;
    top: 10px;
    padding: 10px;
    position: relative;
    font-size: 16px;
    display: block;
    border-bottom: 1px solid rgba(0,0,0,.1);
}
.menu .menu-item ul li a:hover
{
    width: 170px;
    height: 45px;
    background-color: #268aff;
    color:#fff;
    top: 10px;
    padding: 10px;
    position: relative;
    font-size: 16px;
    display: block;
    border-bottom: 1px solid rgba(0,0,0,.1);
}

}