.bd-placeholder-img {
    font-size: 1.125rem;
    text-anchor: middle;
    -webkit-user-select: none;
    -moz-user-select: none;
    user-select: none;
}

@media (min-width: 768px) {
    .bd-placeholder-img-lg {
        font-size: 3.5rem;
    }
}

.b-example-divider {
    height: 3rem;
    background-color: rgba(0, 0, 0, .1);
    border: solid rgba(0, 0, 0, .15);
    border-width: 1px 0;
    box-shadow: inset 0 .5em 1.5em rgba(0, 0, 0, .1), inset 0 .125em .5em rgba(0, 0, 0, .15);
}

.b-example-vr {
    flex-shrink: 0;
    width: 1.5rem;
    height: 100vh;
}

.bi {
    vertical-align: -.125em;
    fill: currentColor;
}

.nav-scroller {
    position: relative;
    z-index: 2;
    height: 2.75rem;
    overflow-y: hidden;
}

.nav-scroller .nav {
    display: flex;
    flex-wrap: nowrap;
    padding-bottom: 1rem;
    margin-top: -1px;
    overflow-x: auto;
    text-align: center;
    white-space: nowrap;
    -webkit-overflow-scrolling: touch;
}

.iframe-container {
    position: relative;
    overflow: hidden;
    width: 100%;
    padding-top: 56.25%;
    /* 16:9 Aspect Ratio (divide 9 by 16 = 0.5625) */
}

.responsive-iframe {
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
    width: 100%;
    height: 100%;
}

#btn-back-to-top {
    position: fixed;
    bottom: 20px;
    right: 20px;
    display: none;
}