main {
    min-height: 100vh;
}
section:not(.cover) {
    margin: 7rem auto;
}
section:last-of-type {
    margin-bottom: 0;
}
section.cover {
    height: 480px;
    background: url(../image/tag.jpg) no-repeat top center;
    background-size: cover;
}
/*****
 * timeline
*****/
.timeline * {
    box-sizing: border-box;
}
.timeline {
    position: relative;
    max-width: 1280px;
    margin: 0 auto;
}
.timeline:after {
    content: "";
    position: absolute;
    width: 6px;
    background-color: #aaa;
    top: 0;
    bottom: 0;
    left: 50%;
    margin-left: -3px;
}
.container {
    padding: 10px 40px;
    position: relative;
    background-color: inherit;
    width: 50%;
}
.container:after {
    content: "";
    position: absolute;
    width: 25px;
    height: 25px;
    right: -17px;
    background-color: #fff;
    border: solid 4px #ff9f55;
    top: 15px;
    border-radius: 50%;
    z-index: 1;
}
.left {
    left: 0;
}
.right {
    left: 50%;
}
.left:before {
    content: "";
    height: 0;
    position: absolute;
    top: 22px;
    width: 0;
    z-index: 1;
    right: 30px;
    border: solid medium #aaa;
    border-width: 10px 0 10px 10px;
    border-color: transparent transparent transparent #aaa;
}
.right::before {
    content: " ";
    height: 0;
    position: absolute;
    top: 22px;
    width: 0;
    z-index: 1;
    left: 30px;
    border: medium solid white;
    border-width: 10px 10px 10px 0;
    border-color: transparent #aaa transparent transparent;
}
.right:after {
    left: -16px;
}
.content {
    padding: 20px 30px;
    background-color: #eee;
    position: relative;
    border-radius: 6px;
}

/*****
 * contact us
*****/
#contact-us div {
    /*height: 30vh;
    display: flex;
    justify-content: center;
    align-items: center;*/
}
#contact-us a {
    text-align: center;
    font-size: 4vw;
    display: block;
    padding: 10vw 3vw;
}
#contact-us a:hover {
    color: #ddd;
    background: #00a2e0;
}

/*****
 * media queries
*****/
@media screen and (min-width: 1200px) {
    section.cover h1 {
        font-size: 60px;
    }
}
@media screen and (max-width: 800px) {
    section.cover h1 {
        font-size: 40px;
    }
}
@media screen and (max-width: 600px) {
    .timeline::after {
        left: 31px;
    }
    .container {
        width: 100%;
        padding-left: 70px;
        padding-right: 25px;
    }
    .container::before {
        left: 60px;
        border: medium solid white;
        border-width: 10px 10px 10px 0;
        border-color: transparent white transparent transparent;
    }
    .left::after, .right::after {
        left: 15px;
    }
    .right {
        left: 0%;
    }
}