/* ========================================
   不空门户 v6 - 三栏响应式布局
   PC: 3栏 | 平板: 2栏(左栏折到顶部) | 手机: 单栏
   ======================================== */

/* ---------- 全局重置 ---------- */
.bk-3col-wrap,
.bk-3col-wrap div,
.bk-3col-wrap ul,
.bk-3col-wrap li,
.bk-3col-wrap a,
.bk-3col-wrap span,
.bk-3col-wrap h3,
.bk-3col-wrap p,
.bk-3col-wrap img,
.bk-3col-wrap button {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

.bk-3col-wrap ul {
    list-style: none;
}

/* ---------- 三栏容器 ---------- */
.bk-3col-wrap {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 16px;
}

/* ---------- 三栏核心 ---------- */
.bk-col-left {
    width: 220px;
    order: 1;
}

.bk-col-center {
    flex: 1;
    min-width: 0;
    order: 2;
}

.bk-col-right {
    width: 240px;
    order: 3;
}

/* ---------- 区域标题 ---------- */
.bk-col-title {
    font-size: 16px;
    font-weight: 700;
    color: #333;
    padding: 8px 0;
    margin-bottom: 12px;
    border-bottom: 2px solid #ff6b35;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.bk-col-title .bk-more {
    font-size: 12px;
    color: #999;
    font-weight: 400;
    text-decoration: none;
}

.bk-col-title .bk-more:hover {
    color: #ff6b35;
}

/* ========== 左栏：图片卡片 ========== */
.bk-img-card {
    background: #fff;
    border-radius: 8px;
    overflow: hidden;
    margin-bottom: 12px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    transition: box-shadow 0.2s, transform 0.2s;
}

.bk-img-card:hover {
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
    transform: translateY(-2px);
}

.bk-img-card a {
    text-decoration: none;
    color: #333;
    display: block;
}

.bk-img-card-pic {
    width: 100%;
    height: 130px;
    overflow: hidden;
    background: #e8e8e8;
}

.bk-img-card-pic img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    border: 0;
    transition: transform 0.3s;
}

.bk-img-card:hover .bk-img-card-pic img {
    transform: scale(1.05);
}

.bk-img-placeholder {
    width: 100%;
    height: 130px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 48px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    opacity: 0.6;
}

.bk-img-card-title {
    padding: 8px 10px;
    font-size: 13px;
    font-weight: 600;
    line-height: 1.4;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.bk-img-card-meta {
    padding: 0 10px 8px;
    font-size: 11px;
    color: #999;
}

/* ========== 中栏：推荐Banner轮播 ========== */
.bk-feature-wrap {
    position: relative;
    width: 100%;
    overflow: hidden;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    background: #e8e8e8;
}

.bk-feature-inner {
    display: flex;
    transition: transform 0.5s ease;
}

.bk-feature-item {
    min-width: 100%;
    position: relative;
}

.bk-feature-item a {
    display: block;
    text-decoration: none;
}

.bk-feature-item img {
    width: 100%;
    height: 300px;
    object-fit: cover;
    display: block;
    border: 0;
}

.bk-feature-placeholder {
    width: 100%;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 28px;
    color: rgba(255,255,255,0.7);
    background: linear-gradient(135deg, #2c3e50, #4ca1af);
}

.bk-feature-caption {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 40px 20px 14px;
    background: linear-gradient(transparent, rgba(0,0,0,0.7));
}

.bk-feature-caption h3 {
    font-size: 17px;
    font-weight: 600;
    color: #fff;
    margin: 0;
    line-height: 1.4;
    text-shadow: 0 1px 3px rgba(0,0,0,0.3);
}

.bk-feature-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    width: 36px;
    height: 36px;
    background: rgba(0,0,0,0.35);
    color: #fff;
    border: none;
    border-radius: 50%;
    font-size: 18px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2;
    opacity: 0;
    transition: opacity 0.3s;
}

.bk-feature-wrap:hover .bk-feature-arrow {
    opacity: 1;
}

.bk-feature-arrow:hover {
    background: rgba(0,0,0,0.6);
}

.bk-feature-prev { left: 10px; }
.bk-feature-next { right: 10px; }

.bk-feature-dots {
    position: absolute;
    bottom: 10px;
    right: 16px;
    display: flex;
    gap: 6px;
    z-index: 2;
}

.bk-feature-dot {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255,255,255,0.5);
    border: none;
    cursor: pointer;
    padding: 0;
    transition: all 0.2s;
}

.bk-feature-dot.active {
    background: #fff;
    transform: scale(1.2);
}

/* ========== 中栏：文章列表 ========== */
.bk-article-list {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    padding: 12px 16px;
}

.bk-article-item {
    display: flex;
    padding: 12px 0;
    border-bottom: 1px dashed #eee;
    gap: 12px;
}

.bk-article-item:last-child {
    border-bottom: none;
}

.bk-article-thumb {
    width: 120px;
    height: 80px;
    flex-shrink: 0;
    border-radius: 6px;
    overflow: hidden;
    background: #e8e8e8;
}

.bk-article-thumb img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
    border: 0;
}

.bk-article-info {
    flex: 1;
    min-width: 0;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.bk-article-title {
    font-size: 14px;
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: 4px;
}

.bk-article-title a {
    color: #333;
    text-decoration: none;
}

.bk-article-title a:hover {
    color: #ff6b35;
}

.bk-article-summary {
    font-size: 12px;
    color: #888;
    line-height: 1.5;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
    margin-bottom: 4px;
}

.bk-article-meta {
    font-size: 11px;
    color: #bbb;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.bk-article-cat {
    color: #ff6b35;
    text-decoration: none;
    font-size: 11px;
}

.bk-article-cat:hover {
    text-decoration: underline;
}

/* ========== 右栏：侧边盒子 ========== */
.bk-side-box {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    margin-bottom: 12px;
    overflow: hidden;
}

.bk-side-box-hd {
    padding: 10px 14px;
    font-size: 14px;
    font-weight: 700;
    color: #333;
    border-bottom: 2px solid #ff6b35;
    background: #fafafa;
}

.bk-side-box-bd {
    padding: 10px 14px;
}

/* 右栏：热门列表 */
.bk-hot-list li {
    padding: 5px 0;
    border-bottom: 1px dashed #eee;
    display: flex;
    align-items: center;
    line-height: 1.4;
}

.bk-hot-list li:last-child {
    border-bottom: none;
}

.bk-hot-list li a {
    font-size: 13px;
    color: #333;
    text-decoration: none;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    flex: 1;
}

.bk-hot-list li a:hover {
    color: #ff6b35;
}

.bk-hot-rank {
    display: inline-block;
    width: 18px;
    height: 18px;
    line-height: 18px;
    text-align: center;
    border-radius: 3px;
    font-size: 11px;
    font-weight: 700;
    margin-right: 6px;
    background: #eee;
    color: #999;
    flex-shrink: 0;
}

.bk-hot-rank-1 { background: #ff6b35; color: #fff; }
.bk-hot-rank-2 { background: #ff8f35; color: #fff; }
.bk-hot-rank-3 { background: #ffaa35; color: #fff; }

/* 右栏：工具按钮 */
.bk-side-tools .bk-side-box-bd {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.bk-tool-btn {
    display: block;
    padding: 8px 0;
    border-radius: 6px;
    text-align: center;
    font-size: 13px;
    font-weight: 600;
    text-decoration: none;
    color: #fff;
    transition: all 0.2s;
}

.bk-tool-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 2px 8px rgba(0,0,0,0.15);
    color: #fff;
}

.bk-tool-forum { background: linear-gradient(135deg, #ff6b35, #ff8f35); }
.bk-tool-search { background: linear-gradient(135deg, #4a90d9, #5ba3e8); }
.bk-tool-login { background: linear-gradient(135deg, #52c41a, #73d13d); }
.bk-tool-home { background: linear-gradient(135deg, #722ed1, #9254de); }

/* 右栏：版块导航标签 */
.bk-forum-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.bk-forum-tag {
    display: inline-block;
    padding: 4px 10px;
    background: #f5f5f5;
    border-radius: 4px;
    font-size: 12px;
    color: #555;
    text-decoration: none;
    transition: all 0.2s;
}

.bk-forum-tag:hover {
    background: #ff6b35;
    color: #fff;
}

/* ========== 空状态 ========== */
.bk-empty-tip {
    background: #fff;
    border-radius: 8px;
    box-shadow: 0 1px 4px rgba(0,0,0,0.08);
    text-align: center;
    padding: 40px 20px;
    color: #999;
}

/* ==============================================
   响应式：大屏PC ≥1200px  —  标准3栏
   ============================================== */

/* 默认就是3栏，不需要额外media */

/* ==============================================
   响应式：中屏PC/平板横屏 960px ~ 1199px
   ============================================== */
@media screen and (max-width: 1199px) {
    .bk-col-left {
        width: 190px;
    }

    .bk-col-right {
        width: 210px;
    }

    .bk-feature-item img,
    .bk-feature-placeholder {
        height: 260px;
    }

    .bk-img-card-pic,
    .bk-img-placeholder {
        height: 110px;
    }
}

/* ==============================================
   响应式：平板 768px ~ 959px
   左栏折到顶部横向排列，中栏+右栏两栏
   ============================================== */
@media screen and (max-width: 959px) {
    .bk-3col-wrap {
        gap: 12px;
    }

    /* 左栏变为顶部横排 */
    .bk-col-left {
        width: 100%;
        order: 1;
        display: flex;
        flex-wrap: wrap;
        gap: 10px;
    }

    .bk-col-left .bk-col-title {
        width: 100%;
    }

    .bk-col-left .bk-img-card {
        width: calc(25% - 8px);
        margin-bottom: 0;
    }

    /* 中栏 */
    .bk-col-center {
        width: calc(100% - 210px - 12px);
        order: 2;
    }

    /* 右栏 */
    .bk-col-right {
        width: 210px;
        order: 3;
    }

    .bk-feature-item img,
    .bk-feature-placeholder {
        height: 220px;
    }
}

/* ==============================================
   响应式：大手机/小平板 600px ~ 767px
   中栏+右栏上下堆叠
   ============================================== */
@media screen and (max-width: 767px) {
    .bk-3col-wrap {
        gap: 12px;
    }

    /* 左栏横排4张变3张 */
    .bk-col-left .bk-img-card {
        width: calc(33.33% - 7px);
    }

    /* 中栏满宽 */
    .bk-col-center {
        width: 100%;
        order: 2;
    }

    /* 右栏满宽，工具按钮横排 */
    .bk-col-right {
        width: 100%;
        order: 3;
    }

    .bk-side-tools .bk-side-box-bd {
        flex-direction: row;
        flex-wrap: wrap;
        gap: 8px;
    }

    .bk-tool-btn {
        flex: 1;
        min-width: 45%;
    }

    .bk-feature-item img,
    .bk-feature-placeholder {
        height: 200px;
    }

    .bk-feature-caption h3 {
        font-size: 15px;
    }

    .bk-article-thumb {
        width: 100px;
        height: 68px;
    }

    .bk-article-summary {
        -webkit-line-clamp: 1;
    }
}

/* ==============================================
   响应式：手机 <600px
   全部单栏
   ============================================== */
@media screen and (max-width: 599px) {
    .bk-3col-wrap {
        gap: 10px;
    }

    /* 左栏横排2张 */
    .bk-col-left .bk-img-card {
        width: calc(50% - 5px);
    }

    .bk-img-card-pic,
    .bk-img-placeholder {
        height: 100px;
    }

    .bk-feature-item img,
    .bk-feature-placeholder {
        height: 180px;
    }

    .bk-feature-caption {
        padding: 30px 14px 10px;
    }

    .bk-feature-caption h3 {
        font-size: 14px;
    }

    .bk-feature-arrow {
        width: 30px;
        height: 30px;
        font-size: 15px;
        opacity: 0.7;
    }

    .bk-article-item {
        gap: 8px;
    }

    .bk-article-thumb {
        width: 80px;
        height: 56px;
    }

    .bk-article-title {
        font-size: 13px;
    }

    .bk-article-summary {
        display: none;
    }

    .bk-col-title {
        font-size: 14px;
    }

    .bk-tool-btn {
        font-size: 12px;
        padding: 7px 0;
    }

    /* 热门列表更紧凑 */
    .bk-hot-list li a {
        font-size: 12px;
    }
}