#app {
    background-color: #4966d8ad;
}

.main {
    width: 450px;
    margin: 0 auto;
    background-color: #ffffff38;
}

/* ------------------------------header--------------------------------- */

.header {
    width: 100%;
    height: 150px;
}

.header a {
    display: block;
    width: 100%;
    height: 100%;
}

.header a img {
    width: 100%;
    height: 100%;
}

/* ------------------------------nav--------------------------------- */

.nav {
    width: 100%;
    height: 44px;
    background-color: #fff;
}

.nav ul {
    width: 100%;
    height: 100%;
}

.nav ul li {
    float: left;
    width: 33.33%;
    height: 100%;
}

.nav ul li a {
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 100%;
    letter-spacing: 1em;
    text-indent: 1em;
}