/* ============================================================
   教师端共享样式 — 侧边栏 + 通用组件
   需要 Bootstrap 5.3
   ============================================================ */

/* ===== 1. 侧边栏布局（桌面端固定，移动端 offcanvas） ===== */
@media (min-width: 992px) {
    .teacher-sidebar {
        visibility: visible !important;
        transform: none !important;
        position: fixed !important;
        top: 0;
        left: 0;
        bottom: 0;
        z-index: 1040;
    }
    .teacher-content {
        margin-left: 280px;
    }
    body > .offcanvas-backdrop {
        display: none !important;
    }
}

/* ===== 2. 侧边栏布局（桌面端固定） ===== */
.teacher-mobile-topbar {
    display: flex;
    align-items: center;
    padding: 10px 16px 10px 56px;
    background: #111827;
    color: #fff;
    min-height: 52px;
}

/* ===== 4. 教师端通用组件 ===== */
.teacher-content {
    background: #f4f6f9;
    min-height: 100vh;
}
.teacher-content .wrap {
    max-width: 1280px;
    margin: 0 auto;
    padding: 28px 16px 52px;
}

/* 摘要卡片网格 */
.summary {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 16px;
    margin-bottom: 22px;
}
@media (max-width: 980px) {
    .summary { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
    .summary { grid-template-columns: 1fr; }
}

/* 面板 */
.panel {
    background: #fff;
    border: 1px solid #e5e7eb;
    border-radius: 14px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, .04);
    padding: 20px;
    margin-bottom: 20px;
}
.panel h2 {
    margin: 0 0 16px;
    font-size: 1.05rem;
}
.section-card {
    border: 0;
    border-radius: 1rem;
    box-shadow: 0 0.75rem 1.75rem rgba(15, 23, 42, 0.06);
    overflow: hidden;
    background: #fff;
    padding: 20px;
    margin-bottom: 20px;
}
.section-card h2 {
    margin: 0 0 4px;
    font-size: 1.05rem;
}
.section-hint {
    color: #64748b;
    font-size: 0.875rem;
    margin-bottom: 16px;
}

/* 热力图 */
.heat-cell {
    font-weight: 600;
    border-radius: 8px;
    text-align: center;
}

/* 通用工具类 */
.empty-box {
    padding: 24px;
    text-align: center;
    color: #9ca3af;
}
.table-scroll {
    overflow-x: auto;
}

/* ===== 5. 表格 ===== */
table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.86rem;
}
th, td {
    text-align: left;
    padding: 12px 10px;
    border-bottom: 1px solid #f3f4f6;
    vertical-align: top;
}
th {
    color: #6b7280;
    font-weight: 600;
    white-space: nowrap;
}