Materialize/doc/user/assets/sass/_nav.scss

.nav {
    border-bottom: 1px solid var(--divider-light);
    background: var(--bg-nav);
    backdrop-filter: saturate(0.5) blur(5px);
    position: fixed;
    width: 100vw;
    z-index: 101;

    .desktop {
        display: flex;
        align-items: center;
        gap: var(--small);

        @media(max-width: 850px) {
            display: none !important;
        }
    }

    .mobile {
        display: none;
        padding: var(--micro) 0;

        a:not(.btn) {
            padding: var(--nano) 0;
            border-bottom: 1px solid var(--divider-light) !important;
        }

        .btn {
            margin-top: var(--milli);
        }

        .active {
            font-weight: bold;
        }

        @media(max-width: 850px) {
            height: calc(100vh - var(--nav-height));

            .row {
                display: flex;
                flex-direction: column;
            }
        }
    }

    &-container {
        display: flex;
        justify-content: space-between;
        flex: 0 0 100%;
        align-items: center;
        height: var(--nav-height);
    }

    a:not([class*="btn"]) {
        text-decoration: none;
        border-bottom: 1px solid transparent;

        &:hover,
        &:focus,
        &.active {
            text-decoration: none;
            color: var(--important);
            border-color: var(--important);
        }
    }

    &-logo {
        display: flex;
        align-items: center;
        font-weight: 600;
        font-size: rem(1.8);
        color: var(--important);

        a {
            display: flex;
            border-bottom: none !important;
        }

        svg {
            margin-right: rem(1.5);
        }
    }
}

.toggle {
    display: none;
    transform: translateX(rem(.8));

    @media(max-width: 850px) {
        display: initial;
    }

    div {
        display: flex;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        height: rem(4.8);
        width: rem(4.8);
        border-radius: 12px;
        transition: all .2s cubic-bezier(0, 0, 0.2, 1);

        span,
        &::before,
        &::after {
            background: var(--sub);
            height: rem(.2);
            width: rem(2.4);
            transition: all .2s cubic-bezier(0, 0, 0.2, 1);
        }

        &::before,
        &::after {
            content: '';
        }

        &::before {
            margin-bottom: rem(.6);
        }

        &::after {
            margin-top: rem(.6);
        }
    }

    &.open {
        div {

            &::before,
            &::after {
                background: var(--important);
            }

            span {
                opacity: 0;
            }

            &:before {
                transform: rotate(-135deg);
                margin-bottom: -10px;
            }

            &::after {
                transform: rotate(135deg);
            }
        }
    }
}

button.show-topics {
    display: none;
    margin: 0 0 var(--small) !important;
    text-align: left;
    font-weight: 300;
    font-size: var(--base);
    color: var(--sub);

    @media(max-width: 850px) {
        display: flex;
    }

    svg {
        height: 20px;
        margin-right: var(--micro);
        stroke: var(--important);
    }
}

button.close-topics {
    display: none;
    position: absolute;
    justify-content: center;
    align-items: center;
    top: 0;
    right: 0;
    transform: translateX(50%) translateY(50%);
    background: var(--bg);
    height: rem(4.8);
    width: rem(4.8);
    border: 1px solid var(--divider-light);
    border-radius: 100%;
    box-shadow: var(--shadow-default);
    transition: all .2s ease-out;

    svg {
        height: 30px;
        width: 30px;

        path {
            stroke: var(--important);
        }
    }

    @media(max-width: 850px) {
        display: flex;
    }
}

body.light {
    .logo-link {
        path {
            fill: var(--black);
        }
    }
}