/*============nav=============*/
nav {
    display: block;
    position: fixed;
    top: 0;
    left: -300px;
    bottom: 0;
    width: 300px;
    background: #fff;
    overflow-x: hidden;
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    transition: .5s;
    z-index: 3;
}
/* ------------------------------------------------------------------------ */


.open nav {
    left: 0;
}

nav .inner {
    padding: 25px;

}

    nav .inner ul {
        list-style: none;
        margin: 0;
        padding: 0;
    }

        nav .inner ul li {
            position: relative;
            margin: 0;
            border-bottom: 1px solid #333;
        }

            nav .inner ul li a {
                display: block;
                color: #333;
                font-size: 16px;
                padding: 0.6em;
                text-decoration: none;
                transition-duration: 0.2s;
                box-sizing:border-box;
            }

                nav .inner ul li a:hover {
                    background: #e4e4e4;

                }

@media screen and (max-width: 640px) {
    nav {
        left: -310px;
        width: 310px;
    }
}
/*============@keyframes=============*/
@keyframes equalizer01 {
    0% {
        width: 70%;
    }

    10% {
        width: 50%;
    }

    20% {
        width: 100%;
    }

    30% {
        width: 10%;
    }

    40% {
        width: 50%;
    }

    50% {
        width: 70%;
    }

    60% {
        width: 50%;
    }

    70% {
        width: 10%;
    }

    80% {
        width: 100%;
    }

    90% {
        width: 10%;
    }

    100% {
        width: 70%;
    }
}

@keyframes equalizer02 {
    0% {
        width: 30%;
    }

    10% {
        width: 20%;
    }

    20% {
        width: 40%;
    }

    30% {
        width: 10%;
    }

    40% {
        width: 20%;
    }

    50% {
        width: 30%;
    }

    60% {
        width: 20%;
    }

    70% {
        width: 10%;
    }

    80% {
        width: 40%;
    }

    90% {
        width: 10%;
    }

    100% {
        width: 30%;
    }
}
/*============.toggle_btn=============*/
.toggle_btn {
    margin-top:20px;
    display: block;
    position: absolute;
    top: 5px;
    right: 0px;
    width: 60px;
    height: 30px;
    transform: translate(0, 0);
    transition: all .5s;
    cursor: pointer;
    z-index: 1;
    position: fixed;
}

.open .toggle_btn {
    right: 10px;
}

.toggle_btn span {
    display: block;
    position: absolute;
    left: 0;
    width: 30px;
    height: 2px;
    background-color: #fff;
    transition: all .5s;
}

    .toggle_btn span:nth-child(1) {
        top: 5px;
        width: 60px;
        animation: equalizer01 7000ms infinite;
    }

    .toggle_btn span:nth-child(2) {
        top: 15px;
        width: 30px;
        animation: equalizer02 5000ms infinite;
        animation-delay: 0.33s;
    }

    .toggle_btn span:nth-child(3) {
        top: 25px;
        width: 20px;
        animation: equalizer02 5000ms infinite;
    }

.open .toggle_btn span {
    background-color: #fff;
    width: 30px;
}

    .open .toggle_btn span:nth-child(1) {
        transform: translate(0, 10px) rotate(-45deg);
        animation: unset;
    }

    .open .toggle_btn span:nth-child(2) {
        opacity: 0;
        animation: unset;
    }

    .open .toggle_btn span:nth-child(3) {
        transform: translate(0, -10px) rotate(45deg);
        animation: unset;
    }

@media screen and (max-width: 640px) {
    .open .toggle_btn {
        right: 10px;
    }
}
/*============#mask=============*/
#mask {
    display: none;
}

.open #mask {
    display: block;
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 100%;
    background: #000;
    opacity: .8;
    z-index: 2;
    cursor: pointer;
    transition: all .5s;
}
/*============main=============*/
main {
    padding: 50px;
}

    main h1 {
        font-family: 'Open Sans', sans-serif;
        font-weight: 400;
        text-align: center;
    }