.lesson-bottom-btn {
    background: #0057ff;
    padding: 12px 18px;
    color: white !important;
    border-radius: 6px;
    font-weight: 600;
    text-decoration: none !important;
    box-shadow: 0 4px 10px rgba(0,0,0,0.25);
}

.lesson-bottom-btn:hover {
    background: #0039c9;
}

/* Bottom page-end navigation buttons */
.lesson-nav {
    margin-top: 40px;
    margin-bottom: 20px;
    display: flex;
    justify-content: space-between;
}

.lesson-nav-button {
    padding: 12px 18px;
    border-radius: 6px;
    text-decoration: none !important;
    font-size: 0.9em;
    font-weight: 600;
    color: white !important;
    background: #0057ff;
    transition: background 0.2s ease;
}

.lesson-nav-button:hover {
    background: #0039c9;
}

/* Lesson index in sidebar */
.lesson-index-title {
    font-size: 0.9em;
    font-weight: 700;
    margin-bottom: 8px;
    margin-top: 10px;
}

.lesson-index {
    list-style: none;
    padding-left: 0;
    margin: 0;
}

.lesson-index li {
    margin-bottom: 6px;
}

.lesson-index li.active a {
    font-weight: 700;
    color: #0057ff !important;
}

/* Improve overall readability */
.lesson-index a {
    text-decoration: none;
    color: var(--md-default-fg-color);
}

/* Chapter Accordion */
.chapter-index-title {
    font-size: 0.9em;
    font-weight: 700;
    margin: 12px 0;
}

.chapter-block {
    margin-bottom: 10px;
}

.chapter-title {
    font-size: 0.9em;
    font-weight: 600;
    cursor: pointer;
}

.chapter-lessons {
    list-style: none;
    padding-left: 16px;
    margin-top: 6px;
}

.chapter-lessons li {
    margin-bottom: 4px;
}

.chapter-lessons li.active > a {
    color: #0057ff !important;
    font-weight: 700;
}