header {
    height: 50px;
    color: #fff;
    display: flex;
    justify-content: center;
    background: rgb(0, 102, 255);
    position: relative;
    z-index: 1000;
    font-family: Arial;
    font-weight: bold;
}

.nav-main {
    width: 98%;
    padding: 0;
    display: flex;
    flex-wrap: wrap;
    margin: 5px auto;
    margin-top: 0px;
    max-width: 1000px;
}

#btn-menu {
    display: none;
}

header label {
    font-size: 48px;
    cursor: pointer;
    display: none;
}

.menu ul {
    margin: 0;
    padding: 0;
    display: flex;
}

.menu ul ul {
    display: none;
    background: -webkit-linear-gradient(90deg, rgb(0, 102, 255) 10%, rgb(120, 167, 221) 90%);
}

a {
    display: block;
    padding: 9px 20px;
    color: #fff;
    text-decoration: none;
}

.menu a:hover {
    height: 25px;
    background: rgba(48, 51, 77, 0.808);
}

.menu a span {
    margin-left: 10px;
}

.menu ul li:hover ul {
    display: block;
    position: absolute;
}

@media (max-width:768px) {
    header label {
        display: block;
    }
    .menu {
        left: 0;
        top: 50px;
        width: 100%;
        position: absolute;
        transform: translateX(-100%);
        transition: all 0.3s;
    }
    .menu ul {
        display: block;
        background: -webkit-linear-gradient(90deg, rgb(0, 102, 255) 10%, rgb(120, 167, 221)90%);
    }
    .menu ul li:hover ul {
        display: none;
        position: static;
    }
    .menu a span {
        position: absolute;
        right: 5px;
    }
    #btn-menu:checked~.menu {
        transform: translateX(0%);
    }
    .menu ul ul {
        background: -webkit-linear-gradient(90deg, rgb(0, 102, 255) 10%, rgb(120, 167, 221)90%);
    }
    .menu ul ul a {
        padding: 15px 40px;
    }
}