/**
 * Topic Notes (Single Topic Notes) Scoped Stylesheet
 * Scoped under .tn-widget-container
 */

/* Hide default theme header on single note view */
body.single-math_note .page-header,
body.single-math_note > .entry-header,
body.single-math_note h1.entry-title,
body.single-math_note .site-main > .page-header,
body.single-math_note header.page-header,
.single-math_note .site-main > .page-header,
.single-math_note .entry-header {
    display: none !important;
}

/* 1. PROGRESS BAR */
.tn-progress-bar-wrap {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: transparent;
    z-index: 99999;
    pointer-events: none;
}

.tn-progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, #3b82f6, #6366f1);
    transition: width 0.08s ease-out;
}

/* 2. MAIN CONTAINER & GRID */
.tn-widget-container {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    color: #1e293b;
    line-height: 1.6;
    box-sizing: border-box;
    width: 100%;
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
    padding: 24px 16px;
    text-align: left;
}

.tn-widget-container *,
.tn-widget-container *::before,
.tn-widget-container *::after {
    box-sizing: border-box;
}

/* Scoped Theme Isolation Reset */
.tn-widget-container h1,
.tn-widget-container h2,
.tn-widget-container h3,
.tn-widget-container h4,
.tn-widget-container h5,
.tn-widget-container h6 {
    margin: 0;
    padding: 0;
    font-weight: 700;
    line-height: 1.3;
    text-transform: none;
    letter-spacing: normal;
    color: #0f172a;
    font-family: inherit;
}

.tn-widget-container p {
    margin: 0 0 12px 0;
    padding: 0;
    line-height: 1.65;
}

.tn-widget-container ul,
.tn-widget-container ol {
    list-style: none !important;
    padding: 0 !important;
    margin: 0 !important;
}

.tn-widget-container a {
    text-decoration: none;
    box-shadow: none;
    color: inherit;
}

.tn-layout-grid {
    display: grid;
    grid-template-columns: 280px minmax(0, 1fr);
    gap: 36px;
    align-items: start;
    width: 100%;
    min-width: 0;
}

.tn-main-content {
    min-width: 0;
    max-width: 100%;
    width: 100%;
}

/* 3. SIDEBAR & TABLE OF CONTENTS */
.tn-sidebar {
    position: sticky;
    top: 24px;
    max-height: calc(100vh - 48px);
    min-width: 0;
    width: 100%;
    display: flex;
    flex-direction: column;
    z-index: 20;
}

.tn-toc-card {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    padding: 16px 8px 16px 16px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
    display: flex;
    flex-direction: column;
    max-height: calc(100vh - 48px);
    overflow: hidden !important;
    word-break: break-word;
    box-sizing: border-box;
}

.tn-widget-container h3.tn-toc-title,
.tn-widget-container .tn-toc-title {
    font-size: 0.8125rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: #64748b;
    margin: 0 0 12px 0;
    padding-right: 8px;
    line-height: 1.2;
    flex-shrink: 0;
}

.tn-toc-list {
    list-style: none !important;
    padding: 0 6px 0 0 !important;
    margin: 0 !important;
    display: flex;
    flex-direction: column;
    gap: 4px;
    overflow-y: auto !important;
    overflow-x: hidden !important;
    flex: 1 1 auto;
    min-height: 0;
    max-height: calc(100vh - 48px - 60px);
    overscroll-behavior: contain;
    scrollbar-width: thin;
    scrollbar-color: #cbd5e1 #f8fafc;
}

/* Custom sleek webkit scrollbar for TOC */
.tn-toc-list::-webkit-scrollbar {
    width: 6px;
}
.tn-toc-list::-webkit-scrollbar-track {
    background: #f8fafc;
    border-radius: 4px;
}
.tn-toc-list::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 4px;
}
.tn-toc-list::-webkit-scrollbar-thumb:hover {
    background: #94a3b8;
}

.tn-toc-item {
    margin: 0;
}

.tn-toc-link {
    display: block;
    padding: 8px 12px;
    border-radius: 6px;
    color: #475569;
    text-decoration: none;
    font-size: 0.875rem;
    font-weight: 500;
    line-height: 1.45;
    transition: all 0.15s ease;
    border-left: 3px solid transparent;
    word-break: break-word;
    overflow-wrap: break-word;
}

/* Force math in TOC to stay inline and not overflow */
.tn-toc-link .lcs-equation,
.tn-toc-link .lcs-equation-display,
.tn-toc-link mjx-container {
    display: inline !important;
    margin: 0 !important;
    padding: 0 !important;
    text-align: left !important;
}

.tn-toc-link mjx-container[display="true"] {
    display: inline !important;
}

.tn-toc-link mjx-container svg {
    max-width: 100% !important;
    height: auto !important;
    display: inline-block !important;
    vertical-align: middle !important;
}

.tn-toc-link:hover {
    color: #0f172a;
    background: #f8fafc;
}

.tn-toc-link.active {
    color: #2563eb;
    background: #eff6ff;
    font-weight: 600;
    border-left-color: #2563eb;
}

/* 4. MAIN CONTENT AREA */
.tn-main-content {
    min-width: 0; /* Prevents overflow issues */
}

/* Breadcrumbs */
.tn-breadcrumb {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 0.875rem;
    color: #64748b;
    margin-bottom: 20px;
}

.tn-breadcrumb a {
    color: #64748b;
    text-decoration: none;
    transition: color 0.15s ease;
}

.tn-breadcrumb a:hover {
    color: #2563eb;
}

.tn-breadcrumb-sep {
    color: #cbd5e1;
    user-select: none;
}

.tn-breadcrumb-current {
    color: #0f172a;
    font-weight: 600;
}

/* Note Header */
.tn-note-header {
    margin-bottom: 36px;
    border-bottom: 1px solid #f1f5f9;
    padding-bottom: 28px;
}

.tn-widget-container .tn-eyebrow {
    display: inline-block;
    font-size: 0.8125rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #2563eb;
    margin-bottom: 8px;
}

.tn-widget-container h1.tn-main-title,
.tn-widget-container .tn-main-title {
    font-size: 2.25rem;
    font-weight: 800;
    letter-spacing: -0.025em;
    color: #0f172a;
    margin: 0 0 12px 0;
    line-height: 1.25;
}

.tn-widget-container .tn-summary {
    font-size: 1.125rem;
    line-height: 1.6;
    color: #475569;
    margin: 0;
    max-width: 760px;
}

/* 5. SECTIONS */
.tn-section {
    margin-bottom: 44px;
    scroll-margin-top: 80px; /* Offset for sticky nav */
}

.tn-widget-container h2.tn-section-heading,
.tn-widget-container .tn-section-heading {
    font-size: 1.5rem;
    font-weight: 700;
    color: #0f172a;
    letter-spacing: -0.02em;
    margin: 0 0 18px 0;
    padding-bottom: 8px;
    border-bottom: 1px solid #e2e8f0;
}

.tn-section-body {
    font-size: 1rem;
    line-height: 1.7;
    color: #334155;
}

.tn-section-body p {
    margin: 0 0 16px 0;
}

.tn-section-body ul,
.tn-section-body ol {
    margin: 0 0 16px 0;
    padding-left: 24px;
}

.tn-section-body li {
    margin-bottom: 8px;
}

/* 6. DEFINITION CARD */
.tn-definition-card {
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    border-left: 4px solid #3b82f6;
    border-radius: 12px;
    padding: 24px;
    margin-bottom: 24px;
}

.tn-definition-label {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #2563eb;
    background: #eff6ff;
    padding: 4px 10px;
    border-radius: 6px;
    margin-bottom: 12px;
}

.tn-definition-content {
    font-size: 1.0625rem;
    line-height: 1.65;
    color: #1e293b;
}

/* 7. FORMULA CARD */
.tn-formula-card {
    background: #0f172a;
    border-radius: 12px;
    padding: 24px;
    color: #f8fafc;
    margin-bottom: 24px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.tn-formula-display {
    font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
    font-size: 1.25rem;
    font-weight: 600;
    color: #38bdf8;
    text-align: center;
    padding: 16px;
    background: #1e293b;
    border-radius: 8px;
    margin-bottom: 14px;
    overflow-x: auto;
}

.tn-formula-explanation {
    font-size: 0.9375rem;
    color: #cbd5e1;
    line-height: 1.6;
    margin: 0;
}

/* 8. WORKED EXAMPLE */
.tn-example-card {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    overflow: hidden;
    margin-bottom: 28px;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.04);
}

.tn-example-header {
    background: #f8fafc;
    padding: 16px 22px;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.tn-example-title {
    font-size: 1.0625rem;
    font-weight: 700;
    color: #0f172a;
    margin: 0;
}

.tn-example-problem {
    padding: 20px 22px;
    border-bottom: 1px dashed #e2e8f0;
    background: #ffffff;
    font-size: 1rem;
    font-weight: 500;
    color: #1e293b;
}

.tn-example-steps {
    padding: 22px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.tn-step-row {
    display: flex;
    align-items: flex-start;
    gap: 14px;
}

.tn-step-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-widgeth: 28px;
    height: 28px;
    border-radius: 50%;
    background: #e0e7ff;
    color: #4338ca;
    font-size: 0.8125rem;
    font-weight: 700;
    flex-shrink: 0;
    margin-top: 1px;
}

.tn-step-text {
    flex-grow: 1;
    font-size: 0.9375rem;
    line-height: 1.6;
    color: #334155;
}

.tn-example-solution-box {
    background: #ecfdf5;
    border-top: 1px solid #a7f3d0;
    padding: 16px 22px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.tn-example-solution-label {
    font-weight: 700;
    color: #059669;
    font-size: 0.9375rem;
}

.tn-example-solution-value {
    font-weight: 600;
    color: #065f46;
    font-size: 1rem;
}

/* 9. COMMON MISTAKE */
.tn-mistake-card {
    background: #fffbeb;
    border: 1px solid #fde68a;
    border-left: 4px solid #f59e0b;
    border-radius: 12px;
    padding: 20px 22px;
    margin-bottom: 24px;
    display: flex;
    align-items: flex-start;
    gap: 16px;
}

.tn-mistake-card.critical {
    background: #fef2f2;
    border-color: #fecaca;
    border-left-color: #ef4444;
}

.tn-mistake-card.info {
    background: #eff6ff;
    border-color: #bfdbfe;
    border-left-color: #3b82f6;
}

.tn-mistake-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    color: #d97706;
    margin-top: 2px;
}

.tn-mistake-card.critical .tn-mistake-icon { color: #dc2626; }
.tn-mistake-card.info .tn-mistake-icon { color: #2563eb; }

.tn-mistake-body h4 {
    margin: 0 0 6px 0;
    font-size: 1rem;
    font-weight: 700;
    color: #92400e;
}

.tn-mistake-card.critical .tn-mistake-body h4 { color: #991b1b; }
.tn-mistake-card.info .tn-mistake-body h4 { color: #1e40af; }

.tn-mistake-body p {
    margin: 0;
    font-size: 0.9375rem;
    line-height: 1.6;
    color: #78350f;
}

.tn-mistake-card.critical .tn-mistake-body p { color: #7f1d1d; }
.tn-mistake-card.info .tn-mistake-body p { color: #1e3a8a; }

/* 10. NEXT STEPS */
.tn-next-steps-card {
    background: linear-gradient(135deg, #f8fafc, #f1f5f9);
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    padding: 28px;
    margin-top: 36px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.tn-next-steps-info h3 {
    margin: 0 0 8px 0;
    font-size: 1.25rem;
    font-weight: 700;
    color: #0f172a;
}

.tn-next-steps-info p {
    margin: 0;
    font-size: 0.9375rem;
    color: #64748b;
}

.tn-btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: #0f172a;
    color: #ffffff;
    border-radius: 10px;
    font-size: 0.9375rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s ease;
    white-space: nowrap;
}

.tn-btn-primary:hover {
    background: #1e293b;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(15, 23, 42, 0.15);
    color: #ffffff;
}

/* 11. PREV / NEXT NAVIGATION */
.tn-nav-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-top: 48px;
    padding-top: 32px;
    border-top: 1px solid #e2e8f0;
}

.tn-nav-card {
    display: flex;
    flex-direction: column;
    padding: 20px;
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    text-decoration: none;
    transition: all 0.2s ease;
}

.tn-nav-card:hover {
    border-color: #cbd5e1;
    transform: translateY(-2px);
    box-shadow: 0 6px 16px -2px rgba(0, 0, 0, 0.06);
}

.tn-nav-card.next {
    text-align: right;
}

.tn-nav-sub {
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: #64748b;
    margin-bottom: 6px;
}

.tn-nav-title {
    font-size: 1.0625rem;
    font-weight: 700;
    color: #0f172a;
    margin: 0;
}

/* 12. FLOATING PDF BUTTON */
.tn-floating-pdf-btn {
    position: fixed;
    bottom: 24px;
    right: 24px;
    z-index: 9999;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: #0f172a;
    color: #ffffff;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 600;
    text-decoration: none;
    box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.25);
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.tn-floating-pdf-btn:hover {
    background: #1e293b;
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 14px 28px -5px rgba(0, 0, 0, 0.3);
    color: #ffffff;
}

/* 13. RESPONSIVE BREAKPOINTS */
@media (max-width: 900px) {
    .elementor-widget-topic_notes .tn-layout-grid,
    .tn-widget-container .tn-layout-grid,
    .tn-layout-grid {
        grid-template-columns: 1fr !important;
        gap: 24px !important;
    }

    .elementor-widget-topic_notes .tn-sidebar,
    .tn-widget-container .tn-sidebar,
    .tn-sidebar {
        position: static !important;
        max-height: none !important;
        width: 100% !important;
        margin-bottom: 24px !important;
    }

    .elementor-widget-topic_notes .tn-toc-card,
    .tn-widget-container .tn-toc-card,
    .tn-toc-card {
        max-height: 380px !important;
        overflow: hidden !important;
    }

    .elementor-widget-topic_notes .tn-toc-list,
    .tn-widget-container .tn-toc-list,
    .tn-toc-list {
        max-height: 310px !important;
        overflow-y: auto !important;
    }

    .tn-main-title {
        font-size: 2rem;
    }

    .tn-next-steps-card {
        flex-direction: column;
        align-items: flex-start;
    }
}

@media (max-width: 640px) {
    .tn-main-title {
        font-size: 1.75rem;
    }

    .tn-nav-container {
        grid-template-columns: 1fr;
    }

    .tn-nav-card.next {
        text-align: left;
    }

    .tn-floating-pdf-btn {
        bottom: 16px;
        right: 16px;
        padding: 10px 16px;
    }
}

/* ==========================================================================
   TOPIC NOTES GRID (Popular Topics Cards)
   ========================================================================== */
.tn-grid-container {
    width: 100%;
    box-sizing: border-box;
}

.tn-grid-section-title {
    font-size: 32px;
    font-weight: 800;
    color: #111827;
    margin: 0 0 28px 0;
    letter-spacing: -0.02em;
    line-height: 1.25;
}

.tn-grid {
    display: grid;
    grid-template-columns: repeat(var(--tn-grid-cols, 3), minmax(0, 1fr));
    column-gap: var(--tn-grid-col-gap, 24px);
    row-gap: var(--tn-grid-row-gap, 24px);
    width: 100%;
    box-sizing: border-box;
}

.tn-card {
    background: #ffffff;
    border: 1px solid #e5e7eb;
    border-radius: 16px;
    padding: 28px 26px;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    transition: transform 0.22s ease, box-shadow 0.22s ease, box-color 0.22s ease;
    text-decoration: none !important;
    position: relative;
    box-sizing: border-box;
    color: inherit;
}

.tn-card.is-clickable {
    cursor: pointer;
}

.tn-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 12px 28px -6px rgba(0, 0, 0, 0.08), 0 4px 10px -4px rgba(0, 0, 0, 0.04);
    border-color: #d1d5db;
}

.tn-card-content {
    flex: 1 1 auto;
    margin-bottom: 24px;
}

.tn-card-eyebrow {
    display: block;
    font-size: 11px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: #16a34a;
    margin-bottom: 12px;
    line-height: 1.3;
}

.tn-card-title {
    font-size: 20px;
    font-weight: 700;
    line-height: 1.35;
    color: #111827;
    margin: 0 0 12px 0;
    transition: color 0.15s ease;
}

.tn-card:hover .tn-card-title {
    color: #0f172a;
}

.tn-card-desc {
    font-size: 14.5px;
    line-height: 1.55;
    color: #4b5563;
    margin: 0;
}

.tn-card-link-wrapper {
    margin-top: auto;
    display: flex;
    align-items: center;
}

.tn-card-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 14px;
    font-weight: 600;
    color: #16a34a;
    text-decoration: none;
    transition: gap 0.2s ease, color 0.15s ease;
}

.tn-card:hover .tn-card-link,
.tn-card-link:hover {
    gap: 10px;
    color: #15803d;
}

.tn-card-link svg {
    transition: transform 0.2s ease;
    flex-shrink: 0;
}

.tn-card:hover .tn-card-link svg {
    transform: translateX(3px);
}

.tn-grid-empty {
    font-size: 15px;
    color: #64748b;
    padding: 32px 0;
    text-align: center;
}

@media (max-width: 1024px) {
    .tn-grid {
        grid-template-columns: repeat(var(--tn-grid-cols, 2), minmax(0, 1fr));
    }
}

@media (max-width: 767px) {
    .tn-grid {
        grid-template-columns: repeat(var(--tn-grid-cols, 1), minmax(0, 1fr));
        gap: 16px;
    }
    .tn-card {
        padding: 22px 20px;
    }
    .tn-grid-section-title {
        font-size: 26px;
        margin-bottom: 20px;
    }
}

/* =========================================================
   10. CHAPTER BOXES & SUB SECTION ACCORDIONS
========================================================= */
.tn-chapter-box {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    padding: 24px;
    margin-bottom: 32px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.03);
    transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.tn-title-wrap {
    display: flex;
    align-items: center;
    gap: 12px;
}

.tn-chapter-box-header {
    margin-bottom: 20px;
    padding-bottom: 12px;
    border-bottom: 2px solid #f1f5f9;
}

.tn-chapter-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: #0f172a;
    margin: 0;
    line-height: 1.3;
}

/* Sub Section Accordions Container */
.tn-subsections-accordions {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-bottom: 20px;
}

/* Accordion Card */
.tn-accordion-item {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 10px;
    overflow: hidden;
    transition: all 0.2s ease;
}

.tn-accordion-item:hover {
    border-color: #cbd5e1;
}

.tn-accordion-item.is-open {
    border-color: #93c5fd;
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.08);
}

/* Accordion Header Button */
.tn-accordion-header {
    width: 100%;
    background: #f8fafc;
    border: none;
    outline: none;
    padding: 14px 18px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    cursor: pointer;
    text-align: left;
    transition: background 0.15s ease;
}

.tn-accordion-item.is-open .tn-accordion-header {
    background: #eff6ff;
    border-bottom: 1px solid #dbeafe;
}

.tn-accordion-header:hover {
    background: #f1f5f9;
}

.tn-accordion-item.is-open .tn-accordion-header:hover {
    background: #e0f2fe;
}

.tn-accordion-title {
    font-size: 15px;
    font-weight: 600;
    color: #1e293b;
    line-height: 1.4;
    flex: 1;
}

.tn-accordion-item.is-open .tn-accordion-title {
    color: #1d4ed8;
}

.tn-accordion-icon {
    width: 26px;
    height: 26px;
    border-radius: 50%;
    background: #ffffff;
    border: 1px solid #cbd5e1;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 16px;
    font-weight: 700;
    color: #2563eb;
    flex-shrink: 0;
    transition: all 0.2s ease;
    user-select: none;
}

.tn-accordion-item.is-open .tn-accordion-icon {
    background: #2563eb;
    color: #ffffff;
    border-color: #2563eb;
}

/* Accordion Body */
.tn-accordion-body {
    padding: 18px 20px;
    background: #ffffff;
}

.tn-accordion-content {
    font-size: 15px;
    line-height: 1.7;
    color: #334155;
}

.tn-accordion-content p {
    margin-top: 0;
    margin-bottom: 12px;
}

.tn-accordion-content p:last-child {
    margin-bottom: 0;
}

/* =========================================================
   INDIVIDUAL EXAMPLE / SUB-SECTION CARDS & HOVER STATES
========================================================= */
.tn-sub-section-card {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 14px;
    margin-bottom: 24px;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.03);
    overflow: hidden;
    transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    scroll-margin-top: 90px;
}

.tn-sub-section-card:hover {
    border-color: #3b82f6;
    box-shadow: 0 10px 25px -5px rgba(59, 130, 246, 0.12), 0 8px 10px -6px rgba(0, 0, 0, 0.04);
    transform: translateY(-2px);
}

.tn-sub-section-card.is-open {
    border-color: #93c5fd;
    box-shadow: 0 8px 24px -4px rgba(37, 99, 235, 0.12);
}

.tn-sub-section-header {
    background: #f8fafc;
    padding: 16px 22px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    cursor: pointer;
    user-select: none;
    transition: background 0.2s ease;
    border-bottom: 1px solid transparent;
}

.tn-sub-section-card:hover .tn-sub-section-header {
    background: #f0f7ff;
}

.tn-sub-section-card.is-open .tn-sub-section-header {
    background: #eff6ff;
    border-bottom-color: #dbeafe;
}

.tn-sub-section-header-left {
    display: flex;
    align-items: center;
    gap: 14px;
    flex: 1;
    min-width: 0;
}

.tn-example-badge {
    display: inline-flex;
    align-items: center;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    background: #dbeafe;
    color: #1e40af;
    padding: 4px 10px;
    border-radius: 6px;
    flex-shrink: 0;
    box-shadow: 0 1px 2px rgba(30, 64, 175, 0.08);
}

.tn-sub-section-title {
    font-size: 1.0625rem;
    font-weight: 700;
    color: #0f172a;
    margin: 0;
    line-height: 1.4;
    flex: 1;
}

.tn-sub-section-card.is-open .tn-sub-section-title {
    color: #1d4ed8;
}

.tn-sub-section-content {
    padding: 22px;
    font-size: 1rem;
    line-height: 1.7;
    color: #334155;
    background: #ffffff;
}

/* TOC Chapter and Sub-item styling */
.tn-toc-item-chapter > .tn-toc-link {
    font-weight: 600;
    color: #0f172a;
}

.tn-toc-item-sub {
    padding-left: 14px;
}

.tn-toc-item-sub > .tn-toc-link {
    font-size: 13px;
    color: #64748b;
}

.tn-toc-item-sub > .tn-toc-link:hover,
.tn-toc-item-sub > .tn-toc-link.active {
    color: #2563eb;
}

/* =========================================================
   14. INLINE MATH EQUATION VERTICAL ALIGNMENT & SPACING
========================================================= */
.tn-widget-container .lcs-equation-inline,
.tn-sub-section-content .lcs-equation-inline,
.tn-accordion-content .lcs-equation-inline {
    display: inline !important;
    vertical-align: baseline !important;
    overflow: visible !important;
    margin: 0 !important;
    padding: 0 0.12em;
    line-height: normal;
}

.tn-widget-container mjx-container[jax="SVG"]:not([display="true"]),
.tn-sub-section-content mjx-container[jax="SVG"]:not([display="true"]),
.tn-accordion-content mjx-container[jax="SVG"]:not([display="true"]),
.tn-widget-container mjx-container:not([display="true"]) {
    margin: 0 !important;
    padding: 0 !important;
    display: inline-block !important;
    vertical-align: 0 !important;
    line-height: 0 !important;
}

.tn-widget-container mjx-container[jax="SVG"]:not([display="true"]) > svg,
.tn-sub-section-content mjx-container[jax="SVG"]:not([display="true"]) > svg,
.tn-accordion-content mjx-container[jax="SVG"]:not([display="true"]) > svg {
    margin: 0 !important;
    display: inline-block !important;
}

/* =========================================================
   15. DISPLAY & BLOCK MATH EQUATIONS & COMPACT SPACING
========================================================= */
.tn-widget-container .lcs-equation-display,
.tn-sub-section-content .lcs-equation-display,
.tn-accordion-content .lcs-equation-display,
.tn-definition-content .lcs-equation-display,
.tn-example-problem-text .lcs-equation-display,
.tn-example-solution-value .lcs-equation-display {
    display: block !important;
    margin: 0.35rem 0 !important;
    padding: 6px 2px !important;
    text-align: center;
    max-width: 100%;
    overflow-x: auto;
    overflow-y: hidden;
    clear: both;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
    scrollbar-color: #cbd5e1 transparent;
}

.tn-widget-container mjx-container[display="true"],
.tn-sub-section-content mjx-container[display="true"],
.tn-accordion-content mjx-container[display="true"],
.tn-definition-content mjx-container[display="true"],
.tn-example-problem-text mjx-container[display="true"],
.tn-example-solution-value mjx-container[display="true"],
.tn-widget-container .katex-display,
.tn-widget-container .tn-formula-display {
    margin: 0.35rem 0 !important;
    padding: 6px 2px !important;
    display: block !important;
    text-align: center;
    max-width: 100%;
    overflow-x: auto;
    overflow-y: hidden;
    line-height: normal !important;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: thin;
    scrollbar-color: #cbd5e1 transparent;
}

.tn-widget-container mjx-container[display="true"]::-webkit-scrollbar,
.tn-widget-container .katex-display::-webkit-scrollbar,
.tn-widget-container .lcs-equation-display::-webkit-scrollbar,
.tn-widget-container .tn-formula-display::-webkit-scrollbar {
    height: 4px;
}

.tn-widget-container mjx-container[display="true"]::-webkit-scrollbar-thumb,
.tn-widget-container .katex-display::-webkit-scrollbar-thumb,
.tn-widget-container .lcs-equation-display::-webkit-scrollbar-thumb,
.tn-widget-container .tn-formula-display::-webkit-scrollbar-thumb {
    background: #cbd5e1;
    border-radius: 4px;
}

/* Consecutive display math equations have minimal clean spacing */
.tn-widget-container mjx-container[display="true"] + mjx-container[display="true"],
.tn-sub-section-content mjx-container[display="true"] + mjx-container[display="true"],
.tn-accordion-content mjx-container[display="true"] + mjx-container[display="true"],
.tn-definition-content mjx-container[display="true"] + mjx-container[display="true"],
.tn-example-problem-text mjx-container[display="true"] + mjx-container[display="true"],
.tn-example-solution-value mjx-container[display="true"] + mjx-container[display="true"] {
    margin-top: 0.2rem !important;
}

/* Paragraph spacing inside notes */
.tn-sub-section-content p,
.tn-accordion-content p,
.tn-definition-content p,
.tn-example-problem-text p,
.tn-example-solution-value p {
    margin-top: 0 !important;
    margin-bottom: 8px !important;
    line-height: 1.65;
}

.tn-sub-section-content p:last-child,
.tn-accordion-content p:last-child,
.tn-definition-content p:last-child,
.tn-example-problem-text p:last-child,
.tn-example-solution-value p:last-child {
    margin-bottom: 0 !important;
}

/* Prevent empty paragraphs or br-only paragraphs from creating space */
.tn-sub-section-content p:empty,
.tn-sub-section-content p:has(> br:only-child),
.tn-accordion-content p:empty,
.tn-accordion-content p:has(> br:only-child),
.tn-definition-content p:empty,
.tn-definition-content p:has(> br:only-child) {
    display: none !important;
    margin: 0 !important;
    padding: 0 !important;
    height: 0 !important;
}