body { 
    overflow-x: hidden;
    background-color: #000;  /* 主题色 */
    color: #fff;
}
.left-aligned { margin-left: auto; }
.bg-dark { background-color: #000 !important; }
.bg-hero { background-color: #45b06cff; }

/* CALLOUT */
.bd-callout { padding:1.25rem; margin-top:1.25rem; margin-bottom:1.25rem; border:1px solid #e9ecef; border-left-width:.25rem; border-radius:.25rem }
.bd-callout h4 { margin-bottom:.25rem }
.bd-callout p:last-child { margin-bottom:0 }
.bd-callout code { border-radius:.25rem }
.bd-callout+.bd-callout { margin-top:-.25rem }
.bd-callout-info { border-left-color:#5bc0de }
.bd-callout-warning { border-left-color:#f0ad4e }
.bd-callout-danger { border-left-color:#d9534f }


/* FLEX 布局 */
.flex-row {
    display: flex;
    flex-direction: row;
}

.flex-column {
    display: flex;
    flex-direction: column;
}

.align-center {
    align-items: center;
}

.justify-center {
    justify-content: center;
}

.justify-between {
    justify-content: space-between;
}

.justify-around {
    justify-content: space-around;
}

.flex-wrap {
    flex-wrap: wrap;
}

/* footer */
footer a { color: white; font-weight: bold; text-decoration: none; }
footer a:hover { color: white; text-decoration: underline; }


/* header */
header {
    width: 100vw;
}

header img {
    width: 100vw;
    height: auto;
}


/* 首页 */
.home_page {
    min-height: 100vh;
    width: 100vw;
    background-color: #000;
}

.home_page > div {
    width: 100vw;
}

.home_page > div > img {
    width: 100vw;
    height: auto;
}

.section-1 {

}

.section-2 {

}

.section-3 {

}

.section-4 {

}

.section-5 {

}