.sgk-container {
    max-width: 900px;
    margin: 0 auto;
    padding: 15px;
    font-family: Arial, sans-serif;
}

.sgk-title {
    text-align: center;
    color: #2c5aa0;
    margin-bottom: 25px;
    font-size: 24px;
    font-weight: bold;
}

/* ---------------- Breadcrumb (Yoast) ---------------- */
.breadcrumb-container {
    text-align: center;
    margin-bottom: 20px;
}
.breadcrumb-container .breadcrumb { font-size: 14px; }
.breadcrumb-container .breadcrumb a {
    color: #0a5181;
    text-decoration: none;
    transition: color 0.2s ease;
}
.breadcrumb-container .breadcrumb a:hover {
    color: #073d63;
    text-decoration: underline;
}
.breadcrumb-container .breadcrumb .separator { margin: 0 8px; color: #999; }
.breadcrumb-container .breadcrumb .current { color: #333; font-weight: 500; }

/* ---------------- Tab (Tập 1 / Tập 2) ---------------- */
.tab-buttons {
    display: flex;
    justify-content: center;
    margin-bottom: 25px;
    gap: 8px;
    flex-wrap: wrap;
}
.tab-button {
    background: #f0f0f0;
    border: 2px solid #ddd;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 6px;
    font-size: 14px;
    font-weight: bold;
    transition: all 0.3s ease;
    min-width: 80px;
    text-align: center;
}
.tab-button:hover { background: #e0e0e0; border-color: #2c5aa0; }
.tab-button.active { background: #2c5aa0; color: #fff; border-color: #2c5aa0; }

.tab-content { display: none; }
.tab-content.active { display: block; }

/* ---------------- Banner chạy tự động ---------------- */
.nv-banner {
    position: relative;
    width: 100%;
    margin-bottom: 25px;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.nv-banner-track {
    display: flex;
    transition: transform 0.6s ease;
}
.nv-banner-slide {
    flex: 0 0 100%;
    min-width: 100%;
}
.nv-banner-slide img {
    display: block;
    width: 100%;
    height: auto;
}
.nv-banner-dots {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 10px;
    display: flex;
    justify-content: center;
    gap: 8px;
}
.nv-banner-dot {
    width: 10px;
    height: 10px;
    border-radius: 50%;
    background: rgba(255,255,255,0.7);
    box-shadow: 0 0 2px rgba(0,0,0,0.3);
    cursor: pointer;
    transition: background 0.2s ease;
}
.nv-banner-dot.active { background: #2c5aa0; }

/* ---------------- Danh sách bài ---------------- */
.lesson-list {
    background: #fff;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 25px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.lesson-section { margin-bottom: 25px; }
.lesson-section:last-child { margin-bottom: 0; }

.section-title {
    color: #2c5aa0;
    font-size: 16px;
    font-weight: bold;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 2px solid #2c5aa0;
}

.lesson-item {
    padding: 6px 0;
    border-bottom: 1px solid #f0f0f0;
    font-size: 14px;
    line-height: 1.4;
}
.lesson-item:last-child { border-bottom: none; }
.lesson-item:hover {
    background: #f9f9f9;
    padding-left: 8px;
    transition: all 0.2s ease;
}

.lesson-link {
    color: #333;
    text-decoration: none;
    display: block;
    padding: 4px 0;
    transition: color 0.2s ease;
}
.lesson-link:hover { color: #2c5aa0; text-decoration: underline; }

/* ---------------- Hộp giới thiệu ---------------- */
.content-box {
    background: #f8f9fa;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 20px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}
.content-title {
    color: #2c5aa0;
    font-size: 18px;
    font-weight: bold;
    margin-bottom: 15px;
    text-align: center;
}

/* ---------------- Responsive ---------------- */
@media (max-width: 768px) {
    .sgk-container { padding: 10px; }
    .sgk-title { font-size: 20px; margin-bottom: 20px; }
    .tab-buttons { gap: 5px; margin-bottom: 20px; }
    .tab-button { padding: 8px 12px; font-size: 12px; min-width: 70px; }
    .lesson-list { padding: 15px; }
    .section-title { font-size: 14px; }
    .lesson-item { font-size: 13px; }
    .content-box { padding: 15px; }
    .content-title { font-size: 16px; }
    .breadcrumb-container .breadcrumb { font-size: 12px; }
    .breadcrumb-container .breadcrumb .separator { margin: 0 4px; }
}
@media (max-width: 480px) {
    .tab-button { padding: 6px 10px; font-size: 11px; min-width: 60px; }
}