html,
body {
    height: 100%;
    margin: 0;
    display: flex;
    flex-direction: column;
    position: relative;
}

header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
}

main {
    flex: 1;
    padding-top: 80px;
}

.show-sm {
    display: none;
}

.show-md {
    display: block;
}

h2,
h3 {
    scroll-margin-top: 90px;
}

#menu {
    position: fixed;
    top: 75px;
    left: 10px;
}

#menu ul li {
    list-style-type: none;
}

#menu ul li a {
    display: block;
    margin: 5px 0 5px -40px;
    font-size: 14px;
    font-weight: bold;
    color: #333;
    min-width: 150px;
    height: 40px;
    line-height: 40px;
    text-decoration: none;
    text-align: center;
    background-color: #d1e7fa;
    border-radius: 8px;
    box-shadow:
        0 2px 4px 0 rgba(0, 0, 0, 0.2),
        0 3px 4px 0 rgba(0, 0, 0, 0.2);
}

#menu ul li a:hover {
    color: #fff;
    background-color: #0b365b !important;
}

.menu-active {
    color: #fff !important;
    background-color: #0b365b !important;
}

.video-container {
    width: 100%;
    max-width: 100%;
    overflow: auto;
    text-align: center;
    background-color: #d1e7fa;
}

.video-container iframe {
    width: 100%;
    max-width: 840px;
    height: 473px;
    margin: 0 auto;
    display: block;
}

.radon-link {
    color: #0f4c81;
    background-color: #d1e7fa;
    text-align: center;
}

.radon-link a {
    font-size: 24px;
    font-weight: bold;
    color: #0f4c81;
    text-decoration: none;
}

.radon-link:hover {
    background-color: #0f4c81;
    background-image: linear-gradient(45deg, #156bb7, #0f4c81, #156bb7, #0f4c81, #156bb7);
}

.radon-link:hover a {
    color: white;
}

@media screen and (max-width: 992px) {
    .show-sm {
        display: block;
    }

    .show-md {
        display: none;
    }
}

.container {
    width: calc(100% - 340px);
    margin: 0 170px;
    padding-bottom: 100px;
}

/* ≥768px */
@media (max-width: 768px) {
    .container {
        width: calc(100% - 20px);
        margin: 0 10px;
    }

    #menu {
        display: none;
    }
}