* { box-sizing: border-box; }
:root {
    --bbs-topline-height: 40px;
    --bbs-header-height: 69px;
}
body {
    margin: 0;
    font-family: "Microsoft YaHei", "PingFang SC", sans-serif;
    color: #1f2d3d;
    background: #f5f7fb;
}
a { color: inherit; text-decoration: none; }
.inner { width: 1200px; max-width: calc(100% - 32px); margin: 0 auto; }
.site-topline {
    background-color: #282828;
    color: #b4b4b4;
    font-size: 13px;
    position: fixed;
    left: 0;
    right: 0;
    top: 0;
    z-index: 210;
    transition: transform .24s ease, opacity .24s ease;
}
.site-topline .inner {
    display: flex;
    justify-content: space-between;
    height: var(--bbs-topline-height);
    align-items: center;
}
.site-topline .bar-inner {
    width: 1200px;
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: 0;
}
.site-topline .bar-inner .group-left,
.site-topline .bar-inner .group-right {
    display: inline-flex;
    align-items: center;
    min-width: 0;
}
.site-topline .bar-inner .group-right {
    margin-left: auto;
}
.site-topline .topline-slogan {
    margin: 0 20px 0 8px;
    white-space: nowrap;
    font-size: 12px;
    letter-spacing: 0;
    color: #8f8f8f;
    overflow: hidden;
    text-overflow: ellipsis;
}
.site-topline .bar-inner .el-button {
    padding: 0 15px;
    color: #b4b4b4;
    font-size: 12px;
    border: 0;
    border-left: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 0;
}
.site-topline .bar-inner .el-button [class*='el-icon-'] {
    color: inherit;
}
.site-topline .bar-inner .el-button:hover {
    color: #ffffff;
}
.site-topline .bar-inner .group-right a {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    color: #b4b4b4;
    margin-right: 0;
    padding: 0 15px;
    font-size: 12px;
    white-space: nowrap;
}
.site-topline .bar-inner .group-right a:hover {
    color: #ffffff;
}
.site-topline .bar-inner .group-right .el-button + .el-button {
    margin-left: 0;
}
.site-topline .bar-inner .group-left > .el-button:first-child,
.site-topline .bar-inner .group-right > .el-button:first-child {
    border-left: 0;
}
.site-topline .bar-inner .group-right > span {
    font-size: 0;
}
.site-header {
    background: #ffffff;
    border-bottom: 1px solid #e6ebf5;
    position: fixed;
    left: 0;
    right: 0;
    top: var(--bbs-topline-height);
    z-index: 200;
}
.site-header-placeholder {
    height: calc(var(--bbs-topline-height) + var(--bbs-header-height));
}
.bbs-header-wrap.topline-hidden .site-topline {
    opacity: 0;
    transform: translateY(-100%);
    pointer-events: none;
}
.bbs-header-wrap.topline-hidden .site-header {
    top: 0;
}
.bbs-header-wrap.topline-hidden .site-header-placeholder {
    height: var(--bbs-header-height);
}
.site-header .inner {
    display: flex;
    align-items: center;
    gap: 24px;
    padding: 14px 0;
}
.brand {
    font-size: 24px;
    font-weight: 700;
    color: #1f3f8f;
    white-space: nowrap;
}
.nav {
    display: flex;
    gap: 14px;
    flex-wrap: wrap;
}
.nav a {
    padding: 8px 12px;
    border-radius: 999px;
    color: #456;
    transition: all .2s;
}
.nav a.active,
.nav a:hover {
    background: #e8efff;
    color: #234ea3;
}
.header-actions {
    margin-left: auto;
    min-width: 280px;
}
.searchbar { display: flex; gap: 8px; }
.searchbar input {
    flex: 1;
    border: 1px solid #d6deef;
    border-radius: 10px;
    padding: 10px 12px;
    outline: none;
}
.searchbar button {
    border: 0;
    border-radius: 10px;
    background: #2f63da;
    color: #fff;
    padding: 0 14px;
    cursor: pointer;
}
.main-wrap { padding: 20px 0 32px; }
.hero {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 14px;
    margin-bottom: 16px;
}
.hero-banner {
    border-radius: 14px;
    background: linear-gradient(130deg, #1d3f8f, #3f65c6);
    color: #fff;
    padding: 28px;
    min-height: 260px;
}
.hero-banner h1 { margin: 0 0 12px; line-height: 1.35; }
.hero-banner p { margin: 0; color: #d6e3ff; line-height: 1.8; }
.actions { margin-top: 16px; display: flex; gap: 10px; flex-wrap: wrap; }
.btn {
    border: 1px solid #d4ddf3;
    background: #fff;
    color: #234ea3;
    border-radius: 10px;
    padding: 8px 14px;
    font-size: 14px;
}
.btn.primary { background: #234ea3; color: #fff; border-color: #234ea3; }
.hero-side { display: grid; gap: 12px; }
.quick-panel, .signin-panel, .card {
    background: #fff;
    border-radius: 14px;
    border: 1px solid #e6ebf5;
    padding: 16px;
}
.thread { padding: 10px 0; border-bottom: 1px dashed #e8edf7; }
.thread:last-child { border-bottom: 0; }
.thread-title { font-size: 15px; font-weight: 600; line-height: 1.5; }
.muted { color: #6f7e96; font-size: 13px; line-height: 1.6; }
.section { margin-top: 14px; }
.channel-grid {
    display: grid;
    gap: 10px;
    grid-template-columns: repeat(6, 1fr);
}
.channel-card {
    background: #fff;
    border: 1px solid #e6ebf5;
    border-radius: 12px;
    padding: 14px;
    text-align: center;
}
.channel-card .icon {
    width: 34px;
    height: 34px;
    border-radius: 50%;
    margin: 0 auto 8px;
    background: #edf3ff;
    color: #1e4cae;
    display: grid;
    place-items: center;
    font-weight: 700;
}
.section-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}
.section-head .title { font-size: 20px; font-weight: 700; }
.section-head .title span { margin-left: 8px; color: #6f7e96; font-size: 14px; }
.more { color: #2b5fcf; font-size: 14px; }
.course-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
}
.course-card {
    background: #fff;
    border: 1px solid #e6ebf5;
    border-radius: 14px;
    overflow: hidden;
}
.course-cover {
    height: 120px;
    background: linear-gradient(130deg, #d9e7ff, #f4f8ff);
}
.course-cover .el-image {
    display: block;
    width: 100%;
    height: 100%;
}
.course-body { padding: 12px; }
.course-title { font-weight: 700; line-height: 1.5; min-height: 46px; }
.course-meta, .course-foot {
    margin-top: 10px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: #6f7e96;
    font-size: 13px;
}
.tag {
    display: inline-block;
    padding: 2px 8px;
    border-radius: 999px;
    background: #edf3ff;
    color: #2956b3;
    margin-right: 6px;
    font-size: 12px;
}
.tag.ai { background: #e8fff2; color: #0f8b4b; }
.price { color: #e75151; font-weight: 700; }
.triple-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
}
.panel-title {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
}
.panel-title strong span { color: #2f63da; margin: 0 2px; }
.panel-title em { color: #6f7e96; font-size: 12px; font-style: normal; margin-left: 6px; }
.rank-item, .hot-card, .new-course-item, .topic-course-item {
    display: flex;
    gap: 10px;
    padding: 10px 0;
    border-bottom: 1px dashed #e8edf7;
}
.rank-item:last-child,
.new-course-item:last-child,
.topic-course-item:last-child,
.hot-card:last-child { border-bottom: 0; }
.thumb {
    width: 62px;
    height: 46px;
    border-radius: 8px;
    background: linear-gradient(135deg, #dce8ff, #edf3ff);
    flex-shrink: 0;
}
.portal-grid, .mix-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
}
.score-board { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-top: 8px; }
.score-item {
    background: #f3f7ff;
    border-radius: 8px;
    padding: 10px;
    text-align: center;
}
.score-item .num { font-weight: 700; color: #2a5ec8; }
.forum-board { display: grid; grid-template-columns: repeat(2, 1fr); gap: 10px; }
.board-card {
    border: 1px solid #e6ebf5;
    border-radius: 10px;
    padding: 10px;
    background: #fafcff;
}
.grid { display: grid; gap: 12px; }
.mini-course .thumb { width: 56px; height: 42px; }

/* 覆盖原首页 system-push 标题字号，避免在 BBS 页面过大 */
.home .system-push .title {
    padding-top: 22px;
    font-size: 20px;
}
.home .system-push .title span:first-child {
    font-size: 20px;
}
.home .system-push .title span:last-child {
    font-size: 12px;
}
.home .system-push .rank a > div > div:first-child,
.home .system-push .new a > div > div:first-child,
.home .system-push .hot a > div > div:first-child {
    font-size: 14px;
    line-height: 1.5;
}
@media (max-width: 1100px) {
    .hero,
    .portal-grid,
    .mix-grid,
    .triple-grid,
    .course-grid,
    .channel-grid {
        grid-template-columns: 1fr 1fr;
    }
    .site-header .inner { flex-wrap: wrap; }
    .header-actions { width: 100%; margin-left: 0; }
    .site-topline .topline-slogan {
        display: none;
    }
}
@media (max-width: 720px) {
    .hero,
    .portal-grid,
    .mix-grid,
    .triple-grid,
    .course-grid,
    .channel-grid,
    .forum-board {
        grid-template-columns: 1fr;
    }
    :root {
        --bbs-topline-height: 34px;
    }
    .site-topline .bar-inner {
        gap: 8px;
    }
    .site-topline .bar-inner .group-left .el-button,
    .site-topline .bar-inner .group-right .el-button {
        padding: 0 4px;
        font-size: 12px;
    }
    .site-topline .bar-inner .group-right .el-button:nth-child(n+4) {
        display: none;
    }
    .section-head { display: block; }
    .section-head .more { display: inline-block; margin-top: 6px; }
}