.article-hero {
    padding: 32px 0 18px;
    background: linear-gradient(180deg, #f8fafc 0, #ffffff 100%);
}

.article-hero__content {
    max-width: 900px;
    padding: 18px 0 8px;
}

.article-hero h1 {
    margin: 12px 0;
    color: #0f172a;
    font-size: clamp(2rem, 4vw, 3.5rem);
    line-height: 1.08;
}

.article-hero p {
    max-width: 780px;
    margin: 0;
    color: #475569;
    font-size: 1.08rem;
    line-height: 1.8;
}

.article-container {
    width: min(100% - 32px, 1180px);
    margin-inline: auto;
}

.article-shell {
    background: #f8fafc;
}

.article-breadcrumb {
    margin-bottom: 20px;
}

.article-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.article-meta span {
    display: inline-flex;
    align-items: center;
    min-height: 32px;
    padding: 6px 11px;
    border: 1px solid #dbeafe;
    border-radius: 999px;
    background: #eff6ff;
    color: #1d4ed8;
    font-size: 0.78rem;
    font-weight: 800;
}

.article-page {
    padding: 24px 0 48px;
}

.article-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 320px;
    gap: 28px;
    align-items: start;
}

.article-main {
    min-width: 0;
}

.article-return {
    margin-bottom: 16px;
}

.article-return a {
    color: var(--primary);
    font-weight: 800;
    text-decoration: none;
}

.article-body,
.article-section,
.article-cta,
.article-side-panel,
.formula-card,
.callout,
.tip-box,
.practice-box,
.mistake-box,
.eeat-box,
.author-note,
.soft-cta,
.schema-note {
    border: 1px solid rgba(148, 163, 184, 0.18);
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 24px 48px -40px rgba(15, 23, 42, 0.28);
}

.article-body {
    padding: 28px;
    color: #334155;
    line-height: 1.82;
}

.article-body h2,
.article-body h3,
.article-body h4 {
    margin: 1.4em 0 0.65em;
    color: #0f172a;
    line-height: 1.2;
}

.article-body h2:first-child,
.article-body h3:first-child,
.article-body p:first-child {
    margin-top: 0;
}

.article-body p,
.article-body ul,
.article-body ol,
.article-body table {
    margin-bottom: 1rem;
}

.article-body img,
.article-body iframe {
    max-width: 100%;
}

.article-body table,
.rev-table,
.quick-revision-table {
    width: 100%;
    border-collapse: collapse;
}

.article-body th,
.article-body td,
.rev-table th,
.rev-table td,
.quick-revision-table th,
.quick-revision-table td {
    padding: 10px 12px;
    border: 1px solid #e2e8f0;
    text-align: left;
}

.formula-card,
.callout,
.tip-box,
.practice-box,
.mistake-box,
.eeat-box,
.author-note,
.soft-cta,
.schema-note {
    margin: 18px 0;
    padding: 18px 20px;
}

.article-auto-section h2,
.article-auto-section h3 {
    margin-top: 0;
}

.formula-card {
    border-color: #bfdbfe;
    background: #eff6ff;
    color: #1e3a8a;
}

.callout,
.tip-box {
    border-color: #99f6e4;
    background: #f0fdfa;
    color: #115e59;
}

.practice-box {
    border-color: #bbf7d0;
    background: #f0fdf4;
    color: #166534;
}

.mistake-box {
    border-color: #fecaca;
    background: #fef2f2;
    color: #991b1b;
}

.eeat-box,
.author-note,
.schema-note {
    background: #f8fafc;
    color: #475569;
}

.soft-cta {
    display: grid;
    gap: 10px;
    border-color: #fed7aa;
    background: #fff7ed;
    color: #9a3412;
}

.progress-bar {
    overflow: hidden;
    height: 8px;
    border-radius: 999px;
    background: #e2e8f0;
}

.progress-fill {
    display: block;
    width: 100%;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, #0f766e, #2563eb);
}

.diagram-box {
    margin: 20px 0;
    padding: 18px;
    border: 1px solid #dbeafe;
    border-radius: 8px;
    background: #f8fbff;
    overflow-x: auto;
}

.timeline-diagram,
.ratio-flow {
    display: grid;
    gap: 12px;
}

.timeline-diagram {
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.ratio-flow {
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    align-items: stretch;
}

.visual-step {
    min-width: 0;
    padding: 14px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #ffffff;
    color: #334155;
}

.visual-step strong {
    display: block;
    margin-bottom: 6px;
    color: #0f172a;
}

.visual-alignment-row {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
    align-items: center;
}

.cluster-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin: 18px 0;
}

.cluster-btn {
    display: inline-flex;
    align-items: center;
    min-height: 38px;
    padding: 8px 12px;
    border-radius: 8px;
    background: #eef2ff;
    color: #3730a3;
    font-weight: 800;
    text-decoration: none;
}

.article-section,
.article-cta {
    margin-top: 22px;
    padding: 24px;
}

.article-section h2,
.article-cta h2,
.article-side-panel h2 {
    margin: 0 0 16px;
    color: #0f172a;
    font-size: 1.35rem;
}

.article-faq {
    display: grid;
    gap: 12px;
}

.article-faq details {
    padding: 15px 16px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #f8fafc;
}

.article-faq summary {
    cursor: pointer;
    color: #0f172a;
    font-weight: 800;
}

.article-faq div {
    margin-top: 10px;
    color: #475569;
    line-height: 1.75;
}

.article-cta .btn {
    margin: 8px 8px 0 0;
}

.article-sidebar {
    position: sticky;
    top: 96px;
}

.article-side-panel {
    padding: 20px;
}

.article-related-links {
    display: grid;
    gap: 10px;
}

.article-related-links a {
    display: block;
    padding: 11px 12px;
    border-radius: 8px;
    background: #f8fafc;
    color: #0f766e;
    font-weight: 800;
    text-decoration: none;
}

.article-related-links a:hover {
    background: #ecfeff;
}

@media (max-width: 1024px) {
    .article-layout {
        grid-template-columns: 1fr;
    }

    .article-sidebar {
        position: static;
    }
}

@media (max-width: 640px) {
    .article-hero {
        padding-top: 22px;
    }

    .article-body,
    .article-section,
    .article-cta,
    .article-side-panel,
    .diagram-box {
        padding: 20px;
    }
}

/* Production article design system overrides.
   These rules intentionally make plain admin HTML look polished without
   changing stored article content or relying on inline CSS. */
.article-shell {
    background:
        linear-gradient(180deg, #ffffff 0, #f8fafc 180px),
        #f8fafc;
}

.article-container {
    width: min(100% - 32px, 1160px);
}

.article-hero {
    padding: 38px 0 24px;
    border-bottom: 1px solid #e2e8f0;
    background:
        radial-gradient(circle at top left, rgba(37, 99, 235, 0.08), transparent 34%),
        linear-gradient(180deg, #ffffff 0, #f8fafc 100%);
}

.article-hero__content {
    max-width: 920px;
}

.article-hero h1 {
    max-width: 920px;
    color: #0b1220;
    font-weight: 850;
    letter-spacing: 0;
}

.article-hero p {
    color: #475569;
    font-size: 1.08rem;
}

.article-meta,
.article-meta-pills {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.article-meta span,
.article-mini-badge,
.article-meta-pills span {
    display: inline-flex;
    align-items: center;
    min-height: 32px;
    padding: 6px 11px;
    border: 1px solid #dbeafe;
    border-radius: 999px;
    background: #eff6ff;
    color: #1d4ed8;
    font-size: 0.78rem;
    font-weight: 800;
}

.article-body,
.article-card,
.article-section,
.article-note,
.article-list-card,
.article-answer-key,
.article-faq-box,
.article-exam-strategy {
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 22px 54px -44px rgba(15, 23, 42, 0.45);
}

.article-body {
    max-width: 100%;
    padding: clamp(22px, 4vw, 38px);
    color: #334155;
    font-size: 1.02rem;
    line-height: 1.82;
    overflow-wrap: anywhere;
}

.article-body > *:first-child {
    margin-top: 0;
}

.article-body > *:last-child {
    margin-bottom: 0;
}

.article-body h2 {
    position: relative;
    margin: 2.05em 0 0.72em;
    padding-top: 0.15rem;
    color: #0f172a;
    font-size: clamp(1.45rem, 2.4vw, 2rem);
    font-weight: 850;
    line-height: 1.18;
}

.article-body h2::before {
    content: "";
    display: block;
    width: 54px;
    height: 4px;
    margin-bottom: 12px;
    border-radius: 999px;
    background: linear-gradient(90deg, #2563eb, #0f766e);
}

.article-body h3 {
    margin: 1.55em 0 0.62em;
    color: #132238;
    font-size: clamp(1.16rem, 1.8vw, 1.45rem);
    font-weight: 820;
    line-height: 1.26;
}

.article-body h4 {
    color: #1e293b;
    font-weight: 800;
}

.article-body p {
    margin: 0 0 1.08rem;
    color: #334155;
}

.article-body strong {
    color: #0f172a;
    font-weight: 850;
}

.article-body a {
    color: #0f766e;
    font-weight: 800;
    text-decoration: underline;
    text-decoration-thickness: 0.08em;
    text-underline-offset: 0.18em;
}

.article-body a:hover {
    color: #115e59;
}

.article-body ul,
.article-body ol {
    display: grid;
    gap: 0.58rem;
    margin: 0 0 1.15rem;
    padding-left: 1.35rem;
}

.article-body li {
    padding-left: 0.18rem;
}

.article-body li::marker {
    color: #2563eb;
    font-weight: 850;
}

.article-body blockquote {
    margin: 1.35rem 0;
    padding: 1rem 1.15rem;
    border-left: 4px solid #f59e0b;
    border-radius: 0 8px 8px 0;
    background: #fffbeb;
    color: #713f12;
    font-weight: 650;
}

.article-body table,
.rev-table,
.quick-revision-table {
    display: table;
    width: 100%;
    margin: 1.2rem 0;
    overflow: hidden;
    border: 1px solid #dbe3ef;
    border-radius: 8px;
    border-collapse: separate;
    border-spacing: 0;
    background: #ffffff;
}

.article-body th,
.rev-table th,
.quick-revision-table th {
    background: #f1f5f9;
    color: #0f172a;
    font-weight: 850;
}

.article-body th,
.article-body td,
.rev-table th,
.rev-table td,
.quick-revision-table th,
.quick-revision-table td {
    padding: 12px 14px;
    border: 0;
    border-bottom: 1px solid #e2e8f0;
    vertical-align: top;
}

.article-body tr:last-child th,
.article-body tr:last-child td,
.rev-table tr:last-child th,
.rev-table tr:last-child td,
.quick-revision-table tr:last-child th,
.quick-revision-table tr:last-child td {
    border-bottom: 0;
}

.formula-card,
.callout,
.tip-box,
.practice-box,
.mistake-box,
.eeat-box,
.author-note,
.soft-cta,
.schema-note,
.article-note,
.article-list-card,
.article-answer-key,
.article-faq-box,
.article-exam-strategy {
    margin: 1.35rem 0;
    padding: clamp(16px, 2.5vw, 22px);
    border-radius: 8px;
    box-shadow: 0 18px 42px -38px rgba(15, 23, 42, 0.45);
}

.formula-card {
    border: 1px solid #bfdbfe;
    border-left: 5px solid #2563eb;
    background: linear-gradient(180deg, #eff6ff 0, #ffffff 100%);
    color: #1e3a8a;
}

.callout {
    border: 1px solid #fde68a;
    border-left: 5px solid #f59e0b;
    background: linear-gradient(180deg, #fffbeb 0, #ffffff 100%);
    color: #713f12;
}

.tip-box,
.article-note {
    border: 1px solid #a7f3d0;
    border-left: 5px solid #10b981;
    background: linear-gradient(180deg, #ecfdf5 0, #ffffff 100%);
    color: #065f46;
}

.practice-box,
.article-exam-strategy {
    border: 1px solid #c7d2fe;
    border-left: 5px solid #4f46e5;
    background: linear-gradient(180deg, #eef2ff 0, #ffffff 100%);
    color: #312e81;
}

.mistake-box {
    border: 1px solid #fecaca;
    border-left: 5px solid #ef4444;
    background: linear-gradient(180deg, #fef2f2 0, #ffffff 100%);
    color: #991b1b;
}

.eeat-box,
.author-note,
.schema-note,
.article-answer-key {
    border: 1px solid #dbe3ef;
    border-left: 5px solid #64748b;
    background: #f8fafc;
    color: #475569;
}

.article-list-card {
    border-color: #e2e8f0;
    background: #ffffff;
}

.article-list-card ul,
.article-list-card ol {
    margin-bottom: 0;
}

.soft-cta {
    display: grid;
    gap: 12px;
    border: 1px solid #fed7aa;
    border-left: 5px solid #f97316;
    background: linear-gradient(135deg, #fff7ed 0, #ffffff 74%);
    color: #9a3412;
}

.soft-cta h2,
.soft-cta h3,
.formula-card h2,
.formula-card h3,
.callout h2,
.callout h3,
.tip-box h2,
.tip-box h3,
.practice-box h2,
.practice-box h3,
.mistake-box h2,
.mistake-box h3 {
    margin-top: 0;
}

.formula-card h2::before,
.callout h2::before,
.tip-box h2::before,
.practice-box h2::before,
.mistake-box h2::before {
    display: none;
}

.progress-bar {
    height: 10px;
    border: 1px solid #dbe3ef;
    background: #e2e8f0;
}

.progress-fill {
    background: linear-gradient(90deg, #10b981, #2563eb);
}

.cluster-nav {
    gap: 10px;
    margin: 1.35rem 0;
}

.cluster-btn {
    min-height: 40px;
    border: 1px solid #dbeafe;
    background: #eff6ff;
    color: #1d4ed8;
    transition: background 0.16s ease, border-color 0.16s ease, color 0.16s ease;
}

.cluster-btn:hover {
    border-color: #bfdbfe;
    background: #dbeafe;
    color: #1e40af;
}

.diagram-box {
    border: 1px solid #c7d2fe;
    background: linear-gradient(180deg, #f8fbff 0, #ffffff 100%);
}

.visual-step {
    box-shadow: 0 12px 28px -26px rgba(15, 23, 42, 0.4);
}

.article-faq-box,
.article-faq details {
    border-color: #dbe3ef;
    background: #ffffff;
}

.article-related-links {
    display: grid;
    gap: 10px;
}

.article-related-links a {
    border: 1px solid #dbe3ef;
    background: #ffffff;
    color: #0f766e;
}

.article-side-panel {
    border-color: #e2e8f0;
}

@media (max-width: 760px) {
    .article-container {
        width: min(100% - 24px, 1160px);
    }

    .article-layout {
        gap: 20px;
    }

    .article-body {
        padding: 22px 18px;
        font-size: 1rem;
    }

    .article-body h2 {
        font-size: 1.38rem;
    }

    .article-body h3 {
        font-size: 1.16rem;
    }

    .article-body table,
    .rev-table,
    .quick-revision-table {
        display: block;
        max-width: 100%;
        overflow-x: auto;
        white-space: nowrap;
    }

    .formula-card,
    .callout,
    .tip-box,
    .practice-box,
    .mistake-box,
    .eeat-box,
    .author-note,
    .soft-cta,
    .article-card,
    .article-note,
    .article-list-card,
    .article-answer-key,
    .article-faq-box,
    .article-exam-strategy {
        padding: 16px;
    }
}

/* Article Detail V2: clean premium edtech composition. */
.article-v2-container {
    width: min(100% - 32px, 1180px);
    margin-inline: auto;
}

.article-v2-hero {
    padding: 16px 0 12px;
    background: #f6f9fd;
}

.article-v2-hero .epw-breadcrumb {
    margin-bottom: 10px;
}

.article-v2-hero-card {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 286px;
    gap: 18px;
    align-items: stretch;
    padding: 18px;
    border: 1px solid #dde7f3;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 26px 76px -64px rgba(15, 23, 42, 0.58);
}

.article-v2-hero-copy {
    display: grid;
    align-content: center;
    min-width: 0;
}

.article-v2-kicker,
.article-v2-meta,
.article-v2-reader-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 7px;
    align-items: center;
}

.article-v2-kicker span,
.article-v2-meta span,
.article-v2-reader-tags span {
    min-height: 28px;
    padding: 4px 9px;
    border: 1px solid #dbe7fb;
    border-radius: 999px;
    background: #f8fbff;
    color: #1d4ed8;
    font-size: 0.72rem;
    font-weight: 850;
}

.article-v2-hero h1 {
    max-width: 780px;
    margin: 10px 0 10px;
    color: #071225;
    font-size: clamp(1.78rem, 2.9vw, 2.7rem);
    font-weight: 850;
    line-height: 1.12;
    letter-spacing: 0;
    text-wrap: balance;
}

.article-v2-hero p {
    max-width: 700px;
    margin: 0 0 11px;
    color: #526276;
    font-size: 0.99rem;
    line-height: 1.64;
}

.article-v2-study-card {
    display: grid;
    align-content: center;
    padding: 16px;
    border: 1px solid #d7e5ff;
    border-radius: 8px;
    background: linear-gradient(180deg, #f8fbff 0, #ffffff 100%);
}

.article-v2-study-card span {
    color: #1d4ed8;
    font-size: 0.72rem;
    font-weight: 850;
    text-transform: uppercase;
}

.article-v2-study-card strong {
    margin: 8px 0 7px;
    color: #0f172a;
    font-size: 1rem;
    line-height: 1.28;
}

.article-v2-study-card p {
    margin: 0;
    color: #64748b;
    font-size: 0.88rem;
    line-height: 1.5;
}

.article-v2-shell {
    padding: 18px 0 56px;
    background: #f6f9fd;
}

.article-v2-layout {
    display: grid;
    grid-template-columns: minmax(0, 840px) 300px;
    gap: 18px;
    align-items: start;
    padding: 12px;
    border: 1px solid #dde7f3;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 30px 88px -68px rgba(15, 23, 42, 0.58);
}

.article-v2-main {
    min-width: 0;
}

.article-v2-parent {
    margin-bottom: 12px;
}

.article-v2-reader {
    overflow: hidden;
    border: 1px solid #dce6f2;
    border-radius: 8px;
    background: #ffffff;
}

.article-v2-reader-head {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid #e2e8f0;
    background: #f8fbff;
}

.article-v2-reader-head h2 {
    margin: 8px 0 0;
    color: #0f172a;
    font-size: 1.12rem;
    line-height: 1.2;
}

.article-v2-body {
    padding: 28px 30px;
    border: 0;
    border-radius: 0;
    box-shadow: none;
    color: #263548;
    font-size: 1rem;
    line-height: 1.76;
}

.article-v2-body h2 {
    grid-template-columns: 4px minmax(0, 1fr);
    column-gap: 10px;
    margin-top: 1.72em;
    margin-bottom: 0.58em;
    font-size: clamp(1.26rem, 1.85vw, 1.62rem);
    line-height: 1.22;
}

.article-v2-body h2::before {
    width: 4px;
    height: 1.18em;
}

.article-v2-body h3 {
    margin-top: 1.28em;
    margin-bottom: 0.5em;
    font-size: clamp(1.06rem, 1.25vw, 1.2rem);
}

.article-v2-body p,
.article-v2-body ul,
.article-v2-body ol,
.article-v2-body table {
    margin-bottom: 0.98rem;
}

.article-v2-body .formula-card,
.article-v2-body .tip-box,
.article-v2-body .practice-box,
.article-v2-body .mistake-box,
.article-v2-body .callout {
    margin: 1rem 0;
    padding: 16px 18px;
    border-radius: 8px;
    box-shadow: 0 18px 44px -40px rgba(15, 23, 42, 0.55);
}

.article-v2-body .formula-card {
    border-left: 6px solid #2563eb;
}

.article-v2-body .tip-box {
    border-left: 6px solid #10b981;
}

.article-v2-body .practice-box {
    border-left: 6px solid #4f46e5;
}

.article-v2-body .mistake-box {
    border-left: 6px solid #ef4444;
}

.article-v2-sidebar {
    position: sticky;
    top: 82px;
    display: grid;
    gap: 12px;
    align-self: start;
}

.article-v2-side-card {
    padding: 16px;
    border: 1px solid #dce6f2;
    border-radius: 8px;
    background: #f8fbff;
}

.article-v2-side-card h2 {
    margin: 9px 0 11px;
    color: #0f172a;
    font-size: 0.98rem;
}

.article-v2-nav,
.article-v2-related {
    display: grid;
    gap: 7px;
}

.article-v2-nav a,
.article-v2-related a {
    display: flex;
    align-items: center;
    min-height: 39px;
    padding: 10px 11px;
    border: 1px solid #dfe8f4;
    border-radius: 8px;
    background: #ffffff;
    color: #0f172a;
    font-size: 0.86rem;
    font-weight: 800;
    line-height: 1.32;
    text-decoration: none;
}

.article-v2-related a {
    color: #0f766e;
}

.article-v2-nav a:hover,
.article-v2-related a:hover {
    border-color: #bfdbfe;
    background: #eff6ff;
}

.article-v2-section {
    margin-top: 16px;
    border-color: #dce6f2;
    box-shadow: none;
}

@media (max-width: 1120px) {
    .article-v2-hero-card,
    .article-v2-layout {
        grid-template-columns: minmax(0, 1fr);
    }

    .article-v2-sidebar {
        position: static;
    }
}

@media (max-width: 760px) {
    .article-v2-container {
        width: min(100% - 20px, 1180px);
    }

    .article-v2-hero {
        padding: 10px 0;
    }

    .article-v2-hero-card,
    .article-v2-layout {
        padding: 8px;
    }

    .article-v2-study-card {
        display: none;
    }

    .article-v2-hero h1 {
        font-size: clamp(1.42rem, 6.8vw, 1.92rem);
    }

    .article-v2-hero p {
        font-size: 0.93rem;
    }

    .article-v2-reader-head {
        align-items: flex-start;
        flex-direction: column;
        padding: 13px 14px;
    }

    .article-v2-reader-tags {
        justify-content: flex-start;
    }

    .article-v2-body {
        padding: 18px 14px;
        font-size: 0.97rem;
        line-height: 1.72;
    }

    .article-v2-body h2 {
        margin-top: 1.45em;
        font-size: 1.16rem;
    }

    .article-v2-body h3 {
        font-size: 1.04rem;
    }

    .article-v2-body .formula-card,
    .article-v2-body .tip-box,
    .article-v2-body .practice-box,
    .article-v2-body .mistake-box,
    .article-v2-body .callout {
        padding: 14px;
    }
}

/* Handcrafted final article composition: board-style edtech learning page. */
.article-hero {
    padding: 14px 0 12px;
    background: #f6f9fd;
}

.article-hero__inner {
    width: min(100% - 32px, 1180px);
}

.article-hero__inner > .epw-breadcrumb {
    margin-bottom: 8px;
}

.article-hero-panel {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 270px;
    gap: 18px;
    align-items: stretch;
    padding: 18px;
    border: 1px solid #dde7f3;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 24px 70px -58px rgba(15, 23, 42, 0.55);
}

.article-hero-main {
    display: grid;
    align-content: center;
}

.article-eyebrow-row {
    display: flex;
    flex-wrap: wrap;
    gap: 7px;
    align-items: center;
    color: #64748b;
    font-size: 0.76rem;
    font-weight: 850;
}

.article-hero h1 {
    max-width: 780px;
    margin: 10px 0 9px;
    font-size: clamp(1.76rem, 2.85vw, 2.62rem);
    line-height: 1.13;
    color: #071225;
}

.article-hero p {
    max-width: 700px;
    margin-bottom: 11px;
    color: #526276;
    font-size: 0.99rem;
    line-height: 1.62;
}

.article-meta-pills span,
.article-mini-badge {
    min-height: 27px;
    padding: 4px 9px;
    border-radius: 999px;
    font-size: 0.71rem;
}

.article-hero-card {
    display: grid;
    align-content: center;
    padding: 16px;
    border: 1px solid #d7e5ff;
    background: linear-gradient(180deg, #f8fbff 0, #ffffff 100%);
    box-shadow: none;
}

.article-hero-card span {
    color: #1d4ed8;
    font-size: 0.72rem;
    font-weight: 850;
    text-transform: uppercase;
}

.article-hero-card strong {
    margin: 8px 0 7px;
    color: #0f172a;
    font-size: 1rem;
}

.article-hero-card p {
    margin: 0;
    font-size: 0.88rem;
    line-height: 1.5;
}

.article-shell {
    background: #f6f9fd;
}

.article-page {
    padding: 18px 0 52px;
}

.article-container {
    width: min(100% - 32px, 1180px);
}

.article-learning-board {
    display: grid;
    grid-template-columns: minmax(0, 830px) 300px;
    gap: 18px;
    align-items: start;
    padding: 12px;
    border: 1px solid #dde7f3;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 28px 84px -66px rgba(15, 23, 42, 0.58);
}

.article-reader-pane {
    min-width: 0;
}

.article-reader-card {
    overflow: hidden;
    border: 1px solid #dce6f2;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: none;
}

.article-reader-header {
    display: flex;
    justify-content: space-between;
    gap: 16px;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid #e2e8f0;
    background: #f8fbff;
}

.article-reader-header h2 {
    margin: 8px 0 0;
    color: #0f172a;
    font-size: 1.12rem;
    line-height: 1.2;
}

.article-reader-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 7px;
    justify-content: flex-end;
}

.article-reader-meta span {
    min-height: 28px;
    padding: 5px 9px;
    border: 1px solid #dbeafe;
    border-radius: 999px;
    background: #ffffff;
    color: #1d4ed8;
    font-size: 0.72rem;
    font-weight: 850;
}

.article-learning-surface .article-body {
    padding: 28px 30px;
}

.article-body {
    font-size: 1rem;
    line-height: 1.76;
}

.article-body h2 {
    grid-template-columns: 4px minmax(0, 1fr);
    column-gap: 10px;
    margin-top: 1.72em;
    margin-bottom: 0.58em;
    font-size: clamp(1.26rem, 1.85vw, 1.62rem);
    line-height: 1.22;
}

.article-body h2::before {
    width: 4px;
    height: 1.18em;
}

.article-body h3 {
    margin-top: 1.28em;
    margin-bottom: 0.5em;
    font-size: clamp(1.06rem, 1.25vw, 1.2rem);
}

.article-body p,
.article-body ul,
.article-body ol,
.article-body table {
    margin-bottom: 0.98rem;
}

.article-auto-section {
    margin: 1.05rem 0;
}

.formula-card,
.tip-box,
.practice-box,
.mistake-box,
.callout {
    margin: 1rem 0;
    padding: 16px 18px;
    border-radius: 8px;
    box-shadow: 0 18px 44px -40px rgba(15, 23, 42, 0.55);
}

.formula-card {
    border-left: 6px solid #2563eb;
}

.tip-box {
    border-left: 6px solid #10b981;
}

.practice-box {
    border-left: 6px solid #4f46e5;
}

.mistake-box {
    border-left: 6px solid #ef4444;
}

.callout {
    border-left: 6px solid #f59e0b;
}

.article-learning-rail {
    position: sticky;
    top: 82px;
    display: grid;
    gap: 12px;
    align-self: start;
}

.article-rail-card {
    border: 1px solid #dce6f2;
    border-radius: 8px;
    background: #f8fbff;
    box-shadow: none;
}

.article-rail-card h2 {
    margin: 9px 0 11px;
    padding-bottom: 0;
    border: 0;
    color: #0f172a;
    font-size: 0.98rem;
}

.article-study-nav,
.article-related-links {
    gap: 7px;
}

.article-study-nav a,
.article-related-links a {
    min-height: 39px;
    padding: 10px 11px;
    border-color: #dfe8f4;
    background: #ffffff;
    color: #0f172a;
    font-size: 0.86rem;
    line-height: 1.32;
    box-shadow: none;
}

.article-related-links a {
    color: #0f766e;
}

.article-section,
.article-cta {
    margin-top: 16px;
    border-color: #dce6f2;
    box-shadow: none;
}

@media (max-width: 1120px) {
    .article-hero-panel,
    .article-learning-board {
        grid-template-columns: minmax(0, 1fr);
    }

    .article-learning-rail {
        position: static;
    }
}

@media (max-width: 760px) {
    .article-hero {
        padding: 10px 0;
    }

    .article-hero__inner,
    .article-container {
        width: min(100% - 20px, 1180px);
    }

    .article-hero-panel,
    .article-learning-board {
        padding: 8px;
    }

    .article-hero-card {
        display: none;
    }

    .article-hero h1 {
        font-size: clamp(1.42rem, 6.8vw, 1.92rem);
    }

    .article-hero p {
        font-size: 0.93rem;
    }

    .article-reader-header {
        align-items: flex-start;
        flex-direction: column;
        padding: 13px 14px;
    }

    .article-reader-meta {
        justify-content: flex-start;
    }

    .article-learning-surface .article-body {
        padding: 18px 14px;
    }

    .article-body {
        font-size: 0.97rem;
        line-height: 1.72;
    }

    .article-body h2 {
        margin-top: 1.45em;
        font-size: 1.16rem;
    }

    .article-body h3 {
        font-size: 1.04rem;
    }

    .formula-card,
    .tip-box,
    .practice-box,
    .mistake-box,
    .callout {
        padding: 14px;
    }
}

/* Final handcrafted composition pass based on browser review. */
.article-hero {
    padding: 18px 0 16px;
    border-bottom: 1px solid #e6edf6;
    background: #f8fbff;
}

.article-hero__inner {
    width: min(100% - 36px, 1140px);
}

.article-hero__inner > .epw-breadcrumb {
    margin-bottom: 10px;
}

.article-hero__grid {
    grid-template-columns: minmax(0, 760px) 270px;
    gap: 22px;
    justify-content: space-between;
}

.article-hero__content {
    min-height: 0;
    padding: 12px 0 10px;
}

.article-hero h1 {
    max-width: 760px;
    margin: 10px 0 10px;
    font-size: clamp(1.86rem, 3.1vw, 2.86rem);
    line-height: 1.12;
    letter-spacing: 0;
}

.article-hero p {
    max-width: 680px;
    font-size: 1.01rem;
    line-height: 1.66;
}

.article-meta-pills {
    gap: 6px;
}

.article-meta-pills span,
.article-mini-badge {
    min-height: 28px;
    padding: 4px 9px;
    font-size: 0.72rem;
    border-color: #dbe7fb;
    background: #ffffff;
}

.article-hero-card {
    align-self: center;
    padding: 15px;
    border-color: #dbe7fb;
    background: #ffffff;
    box-shadow: 0 18px 44px -38px rgba(15, 23, 42, 0.48);
}

.article-hero-card strong {
    margin: 10px 0 8px;
    font-size: 1rem;
}

.article-hero-card li {
    font-size: 0.86rem;
}

.article-page {
    padding: 22px 0 54px;
}

.article-container {
    width: min(100% - 36px, 1140px);
}

.article-workspace {
    position: relative;
    padding: 14px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background:
        linear-gradient(180deg, #ffffff 0, #f8fafc 100%);
    box-shadow: 0 28px 80px -64px rgba(15, 23, 42, 0.52);
}

.article-layout.article-workspace {
    display: grid;
    grid-template-columns: minmax(0, 820px) 284px;
    gap: 16px;
    align-items: start;
    justify-content: center;
}

.article-learning-surface {
    border-color: #dbe4ef;
    background: #ffffff;
    box-shadow: none;
}

.article-content-label {
    padding: 13px 18px;
    background: #f8fbff;
}

.article-learning-surface .article-body {
    padding: clamp(24px, 3vw, 36px);
}

.article-body {
    color: #263548;
    font-size: 1.015rem;
    line-height: 1.78;
}

.article-body h2 {
    grid-template-columns: 4px minmax(0, 1fr);
    column-gap: 11px;
    margin-top: 1.82em;
    margin-bottom: 0.62em;
    font-size: clamp(1.34rem, 2vw, 1.76rem);
    line-height: 1.2;
}

.article-body h2::before {
    width: 4px;
    height: 1.25em;
}

.article-body h3 {
    margin-top: 1.38em;
    margin-bottom: 0.52em;
    font-size: clamp(1.08rem, 1.45vw, 1.28rem);
    line-height: 1.28;
}

.article-body p {
    margin-bottom: 1rem;
}

.article-body ul,
.article-body ol {
    gap: 0.52rem;
    margin-bottom: 1.05rem;
}

.article-auto-section {
    margin: 1.25rem 0;
}

.formula-card,
.tip-box,
.practice-box,
.mistake-box,
.callout,
.soft-cta,
.eeat-box,
.author-note,
.article-note,
.article-exam-strategy {
    margin: 1.18rem 0;
    padding: 18px 19px;
    border-radius: 8px;
    box-shadow: 0 20px 46px -40px rgba(15, 23, 42, 0.5);
}

.formula-card {
    border-left-width: 6px;
    background: linear-gradient(180deg, #eef6ff 0, #ffffff 80%);
}

.tip-box {
    border-left-width: 6px;
    background: linear-gradient(180deg, #ecfdf5 0, #ffffff 80%);
}

.practice-box {
    border-left-width: 6px;
    background: linear-gradient(180deg, #f0f3ff 0, #ffffff 80%);
}

.mistake-box {
    border-left-width: 6px;
    background: linear-gradient(180deg, #fff1f2 0, #ffffff 80%);
}

.formula-card::before,
.tip-box::before,
.practice-box::before,
.mistake-box::before,
.callout::before {
    top: 14px;
    right: 14px;
    width: 28px;
    height: 28px;
}

.article-sidebar {
    top: 78px;
    gap: 12px;
}

.article-side-panel {
    padding: 16px;
    border-color: #dbe4ef;
    box-shadow: none;
}

.article-study-panel {
    background: #f8fbff;
}

.article-study-panel h2,
.article-side-panel h2 {
    margin-bottom: 11px;
    font-size: 1rem;
}

.article-study-nav {
    gap: 7px;
}

.article-study-nav a,
.article-related-links a {
    min-height: 40px;
    padding: 10px 11px;
    border-color: #dfe8f4;
    background: #ffffff;
    font-size: 0.88rem;
}

.article-related-links {
    gap: 8px;
}

.article-related-links a:hover,
.article-study-nav a:hover {
    transform: none;
    box-shadow: inset 0 0 0 1px #bfdbfe;
}

.article-section,
.article-cta {
    margin-top: 16px;
    border-color: #dbe4ef;
    box-shadow: 0 18px 48px -44px rgba(15, 23, 42, 0.46);
}

.article-section h2,
.article-cta h2 {
    font-size: 1.18rem;
}

@media (max-width: 1100px) {
    .article-hero__grid {
        grid-template-columns: minmax(0, 1fr);
    }

    .article-layout.article-workspace {
        grid-template-columns: minmax(0, 1fr);
    }

    .article-sidebar {
        position: static;
        grid-template-columns: 1fr;
    }
}

@media (max-width: 760px) {
    .article-hero {
        padding: 14px 0 14px;
    }

    .article-hero__inner,
    .article-container {
        width: min(100% - 22px, 1140px);
    }

    .article-hero h1 {
        font-size: clamp(1.54rem, 7vw, 2.05rem);
        line-height: 1.14;
    }

    .article-hero p {
        font-size: 0.95rem;
    }

    .article-hero-card {
        display: none;
    }

    .article-workspace {
        padding: 8px;
    }

    .article-learning-surface .article-body {
        padding: 18px 15px;
    }

    .article-body {
        font-size: 0.98rem;
        line-height: 1.72;
    }

    .article-body h2 {
        margin-top: 1.55em;
        font-size: 1.22rem;
    }

    .article-body h3 {
        font-size: 1.06rem;
    }

    .formula-card,
    .tip-box,
    .practice-box,
    .mistake-box,
    .callout,
    .soft-cta,
    .eeat-box,
    .author-note,
    .article-note,
    .article-exam-strategy {
        padding: 15px;
    }
}

/* Article composition redesign: premium edtech learning page. */
.article-hero {
    padding: 24px 0 22px;
    background: #f8fbff;
}

.article-hero__inner {
    width: min(100% - 32px, 1180px);
    margin-inline: auto;
}

.article-hero__inner > .epw-breadcrumb {
    margin-bottom: 14px;
}

.article-hero__grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) 300px;
    gap: 24px;
    align-items: stretch;
}

.article-hero__content {
    display: flex;
    flex-direction: column;
    justify-content: center;
    min-height: 230px;
    padding: 28px 0 18px;
}

.article-hero h1 {
    max-width: 820px;
    margin: 12px 0 12px;
    font-size: clamp(2rem, 3.7vw, 3.35rem);
    line-height: 1.08;
    text-wrap: balance;
}

.article-hero p {
    max-width: 720px;
    font-size: 1.06rem;
    line-height: 1.72;
}

.article-meta-pills {
    gap: 7px;
}

.article-meta-pills span {
    min-height: 30px;
    padding: 5px 10px;
    font-size: 0.74rem;
}

.article-hero-card,
.article-learning-surface,
.article-study-panel {
    border: 1px solid #dbe3ef;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 22px 60px -50px rgba(15, 23, 42, 0.42);
}

.article-hero-card {
    align-self: center;
    padding: 18px;
}

.article-hero-card strong {
    display: block;
    margin: 12px 0 10px;
    color: #0b1628;
    font-size: 1.08rem;
    line-height: 1.3;
}

.article-hero-card ul {
    display: grid;
    gap: 8px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.article-hero-card li {
    display: flex;
    gap: 8px;
    align-items: center;
    color: #475569;
    font-weight: 700;
    font-size: 0.9rem;
}

.article-hero-card li::before,
.article-study-nav a::before {
    content: "";
    width: 7px;
    height: 7px;
    border-radius: 999px;
    background: #10b981;
    flex: 0 0 auto;
}

.article-page {
    padding: 26px 0 58px;
}

.article-layout {
    grid-template-columns: minmax(0, 880px) 292px;
    gap: 28px;
    align-items: start;
}

.article-learning-surface {
    overflow: hidden;
    background:
        linear-gradient(180deg, #f8fbff 0, #ffffff 76px),
        #ffffff;
}

.article-content-label {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-items: center;
    padding: 18px 24px;
    border-bottom: 1px solid #e2e8f0;
    color: #64748b;
    font-size: 0.88rem;
    font-weight: 800;
}

.article-learning-surface .article-body {
    border: 0;
    border-radius: 0;
    box-shadow: none;
}

.article-body {
    padding: clamp(24px, 3.6vw, 42px);
    font-size: 1.035rem;
    line-height: 1.84;
}

.article-body h2 {
    margin-top: 2.05em;
    margin-bottom: 0.78em;
}

.article-body h2 + p,
.article-body h3 + p {
    margin-top: -0.1rem;
}

.article-auto-section {
    margin: 1.55rem 0;
}

.article-body > p + h2,
.article-body > ul + h2,
.article-body > ol + h2,
.article-body > table + h2 {
    padding-top: 0.25rem;
}

.formula-card,
.tip-box,
.practice-box,
.mistake-box,
.callout {
    position: relative;
    padding: 20px 22px;
}

.formula-card::before,
.tip-box::before,
.practice-box::before,
.mistake-box::before,
.callout::before {
    content: "";
    position: absolute;
    top: 16px;
    right: 16px;
    width: 34px;
    height: 34px;
    border-radius: 8px;
    opacity: 0.16;
}

.formula-card::before {
    background: #2563eb;
}

.tip-box::before {
    background: #10b981;
}

.practice-box::before {
    background: #4f46e5;
}

.mistake-box::before {
    background: #ef4444;
}

.callout::before {
    background: #f59e0b;
}

.article-sidebar {
    top: 88px;
    display: grid;
    gap: 16px;
}

.article-side-panel {
    padding: 20px;
}

.article-study-panel h2 {
    margin-top: 12px;
    margin-bottom: 14px;
    padding-bottom: 0;
    border-bottom: 0;
    color: #0b1628;
}

.article-study-nav {
    display: grid;
    gap: 9px;
}

.article-study-nav a {
    display: flex;
    align-items: center;
    gap: 9px;
    min-height: 42px;
    padding: 10px 12px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #f8fafc;
    color: #0f172a;
    font-weight: 800;
    text-decoration: none;
}

.article-study-nav a:hover {
    border-color: #bfdbfe;
    background: #eff6ff;
    color: #1d4ed8;
}

.article-related-links a {
    padding: 14px 14px 14px 18px;
    background: #f8fafc;
}

.article-section,
.article-cta {
    margin-top: 22px;
}

@media (max-width: 1100px) {
    .article-hero__grid,
    .article-layout {
        grid-template-columns: minmax(0, 1fr);
    }

    .article-hero__content {
        min-height: 0;
    }

    .article-hero-card {
        align-self: stretch;
    }

    .article-sidebar {
        position: static;
        grid-template-columns: 1fr;
    }
}

@media (max-width: 760px) {
    .article-hero {
        padding: 18px 0 18px;
    }

    .article-hero__inner {
        width: min(100% - 24px, 1180px);
    }

    .article-hero__grid {
        gap: 14px;
    }

    .article-hero__content {
        padding: 16px 0 4px;
    }

    .article-hero h1 {
        font-size: clamp(1.72rem, 8vw, 2.22rem);
        line-height: 1.12;
    }

    .article-hero p {
        font-size: 0.98rem;
        line-height: 1.68;
    }

    .article-hero-card,
    .article-side-panel,
    .article-learning-surface {
        border-radius: 8px;
    }

    .article-content-label {
        padding: 14px 16px;
    }

    .article-body {
        padding: 20px 16px;
        font-size: 1rem;
        line-height: 1.78;
    }

    .article-body h2 {
        margin-top: 1.75em;
        font-size: 1.28rem;
    }

    .article-body h3 {
        font-size: 1.1rem;
    }

    .formula-card,
    .tip-box,
    .practice-box,
    .mistake-box,
    .callout {
        padding: 16px;
    }
}

/* Premium edtech reading experience. CSS-only layer: no schema, routing,
   rendering-helper, or backend behavior changes. */
.article-page {
    padding: 34px 0 64px;
}

.article-shell {
    background:
        linear-gradient(180deg, #f8fbff 0, #f8fafc 260px),
        #f8fafc;
}

.article-layout {
    grid-template-columns: minmax(0, 900px) 300px;
    gap: 32px;
    justify-content: center;
}

.article-main {
    width: 100%;
}

.article-hero {
    padding: 44px 0 32px;
    border-bottom: 1px solid #e5edf7;
    background:
        linear-gradient(180deg, #ffffff 0, #f8fbff 100%);
}

.article-hero__content {
    max-width: 900px;
    padding: 20px 0 10px;
}

.article-hero h1 {
    max-width: 900px;
    margin: 14px 0 14px;
    color: #071225;
    font-size: clamp(2.15rem, 4.4vw, 3.85rem);
    font-weight: 850;
    line-height: 1.05;
}

.article-hero p {
    max-width: 760px;
    color: #526276;
    font-size: clamp(1.02rem, 1.35vw, 1.16rem);
    line-height: 1.78;
}

.article-meta span,
.article-mini-badge,
.article-meta-pills span {
    min-height: 34px;
    padding: 7px 12px;
    border-color: #d7e5ff;
    background: #f4f8ff;
    color: #1e4fb7;
    box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.72);
}

.article-body {
    padding: clamp(28px, 4vw, 46px);
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #ffffff;
    color: #2f3d4f;
    font-size: 1.035rem;
    line-height: 1.86;
    box-shadow:
        0 1px 0 rgba(15, 23, 42, 0.03),
        0 24px 70px -56px rgba(15, 23, 42, 0.42);
}

.article-body h2 {
    display: grid;
    grid-template-columns: 5px minmax(0, 1fr);
    column-gap: 13px;
    align-items: start;
    margin: 2.25em 0 0.82em;
    color: #0b1628;
    font-size: clamp(1.5rem, 2.35vw, 2.05rem);
    line-height: 1.16;
}

.article-body h2::before {
    width: 5px;
    height: 1.45em;
    margin: 0.03em 0 0;
    border-radius: 999px;
    background: linear-gradient(180deg, #2563eb, #0f766e);
}

.article-body h3 {
    margin: 1.7em 0 0.68em;
    color: #172338;
    font-size: clamp(1.18rem, 1.65vw, 1.42rem);
    font-weight: 850;
}

.article-body p {
    margin-bottom: 1.14rem;
}

.article-body ul,
.article-body ol {
    gap: 0.68rem;
    margin-bottom: 1.25rem;
    padding-left: 1.45rem;
}

.article-body li {
    color: #334155;
}

.article-body li::marker {
    color: #1d4ed8;
}

.article-body strong {
    color: #0b1628;
}

.article-body blockquote {
    border-left-color: #f59e0b;
    background: #fffbeb;
    box-shadow: inset 0 0 0 1px #fde68a;
}

.article-body a {
    color: #0b766e;
    text-decoration-color: rgba(15, 118, 110, 0.35);
}

.article-body a:focus-visible,
.cluster-btn:focus-visible,
.article-related-links a:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.28);
    outline-offset: 3px;
}

.article-body table,
.rev-table,
.quick-revision-table {
    box-shadow: 0 16px 34px -32px rgba(15, 23, 42, 0.36);
}

.article-body th,
.rev-table th,
.quick-revision-table th {
    background: #eef4fb;
}

.formula-card,
.callout,
.tip-box,
.practice-box,
.mistake-box,
.eeat-box,
.author-note,
.soft-cta,
.schema-note,
.article-note,
.article-list-card,
.article-answer-key,
.article-faq-box,
.article-exam-strategy,
.diagram-box {
    border-radius: 8px;
    box-shadow:
        0 1px 0 rgba(15, 23, 42, 0.03),
        0 18px 42px -36px rgba(15, 23, 42, 0.42);
}

.formula-card {
    background: linear-gradient(180deg, #eff6ff 0, #ffffff 82%);
}

.callout {
    background: linear-gradient(180deg, #fffbeb 0, #ffffff 82%);
}

.tip-box,
.article-note {
    background: linear-gradient(180deg, #ecfdf5 0, #ffffff 82%);
}

.practice-box,
.article-exam-strategy {
    background: linear-gradient(180deg, #eef2ff 0, #ffffff 82%);
}

.mistake-box {
    background: linear-gradient(180deg, #fff1f2 0, #ffffff 82%);
}

.soft-cta {
    align-items: start;
    background: linear-gradient(135deg, #fff7ed 0, #ffffff 70%);
}

.article-section,
.article-cta,
.article-side-panel {
    border-color: #e2e8f0;
    border-radius: 8px;
    background: #ffffff;
    box-shadow: 0 20px 54px -48px rgba(15, 23, 42, 0.42);
}

.article-section {
    scroll-margin-top: 96px;
}

.article-faq details {
    border: 1px solid #dbe3ef;
    border-radius: 8px;
    background: #ffffff;
}

.article-faq summary {
    min-height: 44px;
    display: flex;
    align-items: center;
    color: #0b1628;
}

.article-sidebar {
    top: 108px;
}

.article-side-panel {
    padding: 22px;
}

.article-side-panel h2 {
    padding-bottom: 12px;
    border-bottom: 1px solid #e2e8f0;
    font-size: 1.08rem;
}

.article-related-links {
    gap: 12px;
}

.article-related-links a {
    position: relative;
    min-height: 48px;
    padding: 13px 14px 13px 16px;
    border: 1px solid #dbe3ef;
    border-radius: 8px;
    background: #ffffff;
    color: #0f766e;
    line-height: 1.35;
    box-shadow: 0 12px 28px -28px rgba(15, 23, 42, 0.36);
}

.article-related-links a::before {
    content: "";
    position: absolute;
    inset: 12px auto 12px 0;
    width: 4px;
    border-radius: 999px;
    background: #14b8a6;
    opacity: 0;
}

.article-related-links a:hover {
    border-color: #99f6e4;
    background: #f0fdfa;
    color: #115e59;
}

.article-related-links a:hover::before {
    opacity: 1;
}

.cluster-btn {
    min-height: 42px;
    padding: 9px 13px;
    border-color: #d7e5ff;
    background: #f4f8ff;
    box-shadow: 0 10px 24px -24px rgba(15, 23, 42, 0.35);
}

.progress-bar {
    height: 11px;
    background: #e8eef7;
}

.diagram-box {
    background: linear-gradient(180deg, #f8fbff 0, #ffffff 82%);
}

.visual-step {
    min-height: 100%;
    border-color: #dbe3ef;
}

@media (max-width: 1100px) {
    .article-layout {
        grid-template-columns: minmax(0, 900px);
    }

    .article-sidebar {
        position: static;
    }

    .article-side-panel {
        margin-top: 4px;
    }
}

@media (max-width: 760px) {
    .article-page {
        padding: 22px 0 42px;
    }

    .article-hero {
        padding: 28px 0 22px;
    }

    .article-hero h1 {
        font-size: clamp(1.85rem, 9vw, 2.45rem);
        line-height: 1.1;
    }

    .article-meta span,
    .article-mini-badge,
    .article-meta-pills span {
        min-height: 34px;
        font-size: 0.76rem;
    }

    .article-body {
        padding: 22px 18px;
        border-radius: 8px;
        line-height: 1.78;
    }

    .article-body h2 {
        grid-template-columns: 4px minmax(0, 1fr);
        column-gap: 10px;
        margin-top: 1.9em;
        font-size: 1.36rem;
    }

    .article-body h3 {
        font-size: 1.14rem;
    }

    .article-body ul,
    .article-body ol {
        padding-left: 1.25rem;
    }

    .article-related-links a,
    .cluster-btn {
        min-height: 46px;
    }
}

/* Desktop article density pass. Mobile article layout remains controlled above. */
@media (min-width: 1200px) {
    .article-page {
        padding-top: 28px;
        padding-bottom: 48px;
    }

    .article-hero {
        padding: 28px 0 22px;
    }

    .article-hero__inner,
    .article-container,
    .article-v2-container {
        width: min(100% - 40px, 1120px);
    }

    .article-layout,
    .article-hero__grid,
    .article-v2-layout {
        gap: 20px;
    }

    .article-hero h1,
    .article-v2-hero h1 {
        font-size: clamp(1.9rem, 3vw, 3rem);
        line-height: 1.08;
        margin-top: 10px;
        margin-bottom: 10px;
    }

    .article-hero p,
    .article-v2-hero p {
        font-size: 0.98rem;
        margin-bottom: 10px;
    }

    .article-hero-panel,
    .article-reader-card,
    .article-v2-hero-card,
    .article-v2-reader-card {
        border-radius: 8px;
    }

    .article-reader-card,
    .article-v2-reader-card {
        padding: 22px 26px;
    }

    .article-body,
    .article-v2-body {
        padding: 24px 28px;
        font-size: 0.98rem;
        line-height: 1.72;
    }

    .article-body h2,
    .article-v2-body h2 {
        margin-top: 1.65em;
        margin-bottom: 0.55em;
        font-size: clamp(1.24rem, 1.65vw, 1.62rem);
    }

    .article-body h3,
    .article-v2-body h3 {
        margin-top: 1.25em;
        font-size: clamp(1.04rem, 1.2vw, 1.18rem);
    }

    .formula-card,
    .article-body .formula-card,
    .article-v2-body .formula-card,
    .article-list-card {
        margin: 1rem 0;
        padding: 16px 18px;
    }

    .article-sidebar,
    .article-v2-sidebar,
    .article-side-panel,
    .article-rail-card {
        padding: 16px;
    }

    .article-study-nav a,
    .article-related-links a,
    .cluster-btn {
        min-height: 40px;
        padding: 9px 12px;
        font-size: 0.86rem;
    }
}
.article-premium-cta {
    border: 1px solid #dbeafe;
    background: linear-gradient(135deg, #eff6ff 0%, #fff7ed 100%);
}

.article-premium-lock {
    border-color: #fed7aa;
    box-shadow: 0 20px 54px -44px rgba(15, 23, 42, 0.6);
}

.article-premium-lock .article-mini-badge {
    background: #fff7ed;
    color: #c2410c;
    border-color: #fed7aa;
}

.article-conversion-strip {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 12px;
    margin-top: 18px;
}

.article-conversion-card {
    min-width: 0;
    padding: 16px;
    border: 1px solid #dbeafe;
    border-radius: 12px;
    background: #ffffff;
    color: #0f172a;
    text-decoration: none;
    box-shadow: 0 14px 38px -34px rgba(15, 23, 42, 0.55);
    transition: border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}

.article-conversion-card:hover,
.article-conversion-card:focus {
    border-color: #2563eb;
    color: #0f172a;
    transform: translateY(-1px);
    box-shadow: 0 18px 44px -34px rgba(37, 99, 235, 0.5);
}

.article-conversion-card span {
    display: block;
    margin-bottom: 6px;
    color: #2563eb;
    font-size: 0.74rem;
    font-weight: 800;
    text-transform: uppercase;
    letter-spacing: 0;
}

.article-conversion-card strong,
.article-conversion-card small {
    display: block;
    min-width: 0;
    white-space: normal;
    word-break: normal;
}

.article-conversion-card strong {
    font-size: 0.98rem;
    line-height: 1.25;
}

.article-conversion-card small {
    margin-top: 6px;
    color: #64748b;
    line-height: 1.45;
}

.article-conversion-card--primary {
    border-color: #fed7aa;
    background: linear-gradient(135deg, #fff7ed 0%, #eff6ff 100%);
}

.article-conversion-card--primary span {
    color: #f97316;
}

.article-next-step-cta .btn {
    margin: 6px 8px 0 0;
}

.article-section-head {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 14px;
    margin-bottom: 14px;
}

.article-section-head h2 {
    margin: 4px 0 0;
}

.article-auto-link-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 14px;
}

.article-auto-link-grid--continue,
.article-auto-link-grid--practice {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.article-auto-link-card {
    min-width: 0;
    padding: 16px;
    border: 1px solid #e2e8f0;
    border-radius: 12px;
    background: #fff;
    color: #0f172a;
    text-decoration: none;
    box-shadow: 0 14px 42px -36px rgba(15, 23, 42, 0.5);
    transition: border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}

.article-auto-link-card:hover,
.article-auto-link-card:focus {
    border-color: #2563eb;
    color: #0f172a;
    transform: translateY(-1px);
    box-shadow: 0 20px 50px -38px rgba(37, 99, 235, 0.55);
}

.article-auto-link-card span {
    display: block;
    margin-bottom: 8px;
    color: #2563eb;
    font-size: 0.76rem;
    font-weight: 800;
    line-height: 1.35;
}

.article-auto-link-card strong,
.article-auto-link-card small {
    display: block;
    min-width: 0;
    white-space: normal;
    word-break: normal;
}

.article-auto-link-card strong {
    font-size: 1rem;
    line-height: 1.3;
}

.article-auto-link-card small {
    margin-top: 8px;
    color: #64748b;
    line-height: 1.5;
}

.article-auto-link-card--compact {
    padding: 14px 16px;
}

.article-auto-link-card--practice {
    border-color: #dbeafe;
    background: #f8fafc;
}

.article-auto-link-card--practice span {
    color: #f97316;
}

@media (max-width: 900px) {
    .article-conversion-strip {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .article-auto-link-grid,
    .article-auto-link-grid--continue,
    .article-auto-link-grid--practice {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }
}

@media (max-width: 560px) {
    .article-conversion-strip {
        grid-template-columns: 1fr;
    }

    .article-section-head {
        display: block;
    }

    .article-auto-link-grid,
    .article-auto-link-grid--continue,
    .article-auto-link-grid--practice {
        grid-template-columns: 1fr;
    }

    .article-next-step-cta .btn {
        width: 100%;
        margin-right: 0;
    }
}

/* Step 6I: article-only performance and Core Web Vitals guardrails. */
.article-page,
.article-page * {
    box-sizing: border-box;
}

.article-body img,
.article-body picture,
.article-body video,
.article-body iframe {
    display: block;
    max-width: 100%;
}

.article-body img,
.article-body video {
    height: auto;
}

.article-body img {
    border-radius: 10px;
}

.article-body iframe {
    width: 100%;
    aspect-ratio: 16 / 9;
    border: 0;
}

.article-section,
.article-cta,
.article-auto-links,
.article-sidebar,
.article-v2-sidebar {
    contain: layout paint style;
}

@supports (content-visibility: auto) {
    .article-section,
    .article-cta,
    .article-auto-links,
    .article-sidebar {
        content-visibility: auto;
        contain-intrinsic-size: auto 360px;
    }

    .article-v2-sidebar {
        content-visibility: auto;
        contain-intrinsic-size: auto 520px;
    }
}

.article-conversion-card,
.article-auto-link-card {
    box-shadow: 0 10px 26px -24px rgba(15, 23, 42, 0.42);
    transition: border-color 0.16s ease, box-shadow 0.16s ease;
}

.article-conversion-card:hover,
.article-conversion-card:focus,
.article-auto-link-card:hover,
.article-auto-link-card:focus {
    transform: none;
    box-shadow: 0 12px 30px -24px rgba(37, 99, 235, 0.42);
}

@media (prefers-reduced-motion: reduce) {
    .article-page *,
    .article-hero *,
    .article-v2-hero * {
        scroll-behavior: auto !important;
        transition-duration: 0.01ms !important;
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
    }
}

@media (max-width: 760px) {
    .article-hero,
    .article-v2-hero {
        padding-top: 20px;
        padding-bottom: 18px;
    }

    .article-hero-panel,
    .article-v2-hero-card,
    .article-learning-surface,
    .article-reader-card,
    .article-section,
    .article-cta {
        box-shadow: none !important;
    }

    .article-section,
    .article-cta,
    .article-auto-links {
        margin-top: 14px;
        padding: 16px;
    }

    .article-conversion-card,
    .article-auto-link-card {
        padding: 14px;
        box-shadow: none;
    }

    .article-body img {
        border-radius: 8px;
    }
}

/* Step 6J: final reading-experience polish. */
.article-body,
.article-v2-body {
    max-width: 78ch;
    margin-inline: auto;
    font-size: 1rem;
    line-height: 1.78;
}

.article-body p,
.article-body li {
    color: #334155;
}

.article-body p,
.article-body ul,
.article-body ol,
.article-body blockquote,
.article-body table,
.article-body .formula-card,
.article-body .tip-box,
.article-body .practice-box,
.article-body .mistake-box {
    margin-top: 0;
    margin-bottom: 1.05rem;
}

.article-body h2,
.article-body h3,
.article-body h4 {
    color: #0f172a;
    max-width: 100%;
    overflow-wrap: normal;
    word-break: normal;
}

.article-body h2 {
    margin-top: 1.8rem;
    margin-bottom: 0.75rem;
    line-height: 1.24;
}

.article-body h3 {
    margin-top: 1.35rem;
    margin-bottom: 0.55rem;
    line-height: 1.32;
}

.article-body a,
.article-auto-link-card,
.article-conversion-card,
.article-cta .btn,
.article-related-links a,
.article-study-nav a {
    outline-offset: 3px;
}

.article-body a:focus-visible,
.article-auto-link-card:focus-visible,
.article-conversion-card:focus-visible,
.article-cta .btn:focus-visible,
.article-related-links a:focus-visible,
.article-study-nav a:focus-visible {
    outline: 3px solid rgba(37, 99, 235, 0.38);
    outline-offset: 3px;
}

.article-body code,
.article-body pre,
.article-body kbd,
.article-body var,
.article-body samp {
    overflow-wrap: anywhere;
    word-break: normal;
}

.article-body pre {
    max-width: 100%;
    overflow-x: auto;
    padding: 14px;
    border-radius: 10px;
    background: #0f172a;
    color: #f8fafc;
}

.article-body table,
.article-body .rev-table,
.article-body .quick-revision-table,
.article-v2-body table,
.article-v2-body .rev-table,
.article-v2-body .quick-revision-table {
    display: block;
    width: 100%;
    max-width: 100%;
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    border-spacing: 0;
}

.article-body th,
.article-body td {
    min-width: 120px;
}

.formula-card,
.tip-box,
.practice-box,
.mistake-box,
.article-body .formula-card,
.article-body .tip-box,
.article-body .practice-box,
.article-body .mistake-box,
.article-v2-body .formula-card,
.article-v2-body .tip-box,
.article-v2-body .practice-box,
.article-v2-body .mistake-box {
    border-radius: 12px;
    padding: 18px;
    line-height: 1.68;
    box-shadow: none;
}

.formula-card {
    border-left: 4px solid #2563eb;
    background: #eff6ff;
}

.tip-box {
    border-left: 4px solid #f97316;
    background: #fff7ed;
}

.practice-box {
    border-left: 4px solid #16a34a;
    background: #f0fdf4;
}

.mistake-box {
    border-left: 4px solid #dc2626;
    background: #fef2f2;
}

.article-premium-lock {
    background: linear-gradient(135deg, #fff7ed 0%, #eff6ff 100%);
}

.article-premium-lock h2 {
    margin-bottom: 8px;
}

.article-premium-lock p {
    max-width: 62ch;
}

.article-conversion-strip,
.article-auto-link-grid {
    align-items: stretch;
}

.article-conversion-card,
.article-auto-link-card {
    display: flex;
    flex-direction: column;
    gap: 4px;
    border-radius: 10px;
}

.article-conversion-card small,
.article-auto-link-card small {
    margin-top: auto;
}

.article-auto-link-card span,
.article-conversion-card span {
    overflow-wrap: anywhere;
}

@media (max-width: 760px) {
    .article-body,
    .article-v2-body {
        max-width: 100%;
        font-size: 0.98rem;
        line-height: 1.72;
    }

    .article-body p,
    .article-body ul,
    .article-body ol,
    .article-body blockquote,
    .article-body table,
    .article-body .formula-card,
    .article-body .tip-box,
    .article-body .practice-box,
    .article-body .mistake-box {
        margin-bottom: 0.9rem;
    }

    .article-body h2 {
        margin-top: 1.45rem;
        margin-bottom: 0.58rem;
        font-size: clamp(1.32rem, 5.4vw, 1.62rem);
    }

    .article-body h3 {
        margin-top: 1.1rem;
        margin-bottom: 0.45rem;
        font-size: clamp(1.1rem, 4.4vw, 1.32rem);
    }

    .formula-card,
    .tip-box,
    .practice-box,
    .mistake-box,
    .article-body .formula-card,
    .article-body .tip-box,
    .article-body .practice-box,
    .article-body .mistake-box {
        padding: 14px;
        border-radius: 10px;
    }

    .article-premium-lock {
        gap: 12px;
    }

    .article-conversion-card strong,
    .article-auto-link-card strong {
        font-size: 0.96rem;
    }
}

.summary-card,
.important-box {
    margin: 24px 0;
    padding: 20px 22px;
    border-radius: 18px;
    border: 1px solid #e2e8f0;
    background: #ffffff;
    box-shadow: 0 16px 34px -30px rgba(15, 23, 42, .32);
}

.summary-card {
    border-left: 5px solid #f97316;
    background: linear-gradient(135deg, #fff7ed, #ffffff);
}

.important-box {
    border-left: 5px solid #2563eb;
    background: linear-gradient(135deg, #eff6ff, #ffffff);
}

.summary-card h3,
.important-box h3,
.formula-card h3,
.tip-box h3,
.practice-box h3,
.mistake-box h3 {
    margin: 0 0 12px;
    font-size: 1.15rem;
    font-weight: 900;
    color: #0f172a;
}

.article-body p {
    line-height: 1.8;
}

.article-body ul,
.article-body ol {
    margin: 12px 0 18px 22px;
    line-height: 1.8;
}