/* Gauss AI - Blog v3.0 (2026-04-25)
   Listing page (hero, category filter, featured, grid) + article typography.
   Aligned with home PT identity:
     - Bell Wave radius (--radius-bell) as brand silhouette
     - Brand gradient as visual soul
     - No-Line Rule: zero borders for sectioning
     - Tonal layering: white card on sky-50 page background
   Stack: pure modular CSS. No Tailwind. SEO/GEO-first. */

/* ============================================================
   1. BLOG LISTING — Hero
   ============================================================ */
.blog-listing {
    padding: calc(var(--header-height) + var(--space-6)) var(--space-3) var(--space-12);
    max-width: 1120px;
    margin: 0 auto;
}

.blog-listing__header {
    text-align: center;
    max-width: 640px;
    margin: 0 auto var(--space-6);
    padding: var(--space-4) 0 var(--space-2);
}

.blog-listing__header h1 {
    font-family: var(--font-brand);
    font-weight: 800;
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    line-height: 1.08;
    letter-spacing: -0.02em;
    margin-bottom: var(--space-2);
    color: var(--color-text);
}

.blog-listing__header p {
    font-size: var(--text-body-lg);
    line-height: 1.6;
    color: var(--gauss-ink-500);
    font-weight: 500;
    font-style: italic;
}

/* ============================================================
   2. CATEGORY FILTER PILLS
   ============================================================ */
.blog-listing__categories {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: var(--space-6);
}

.category-pill {
    appearance: none;
    border: 0;
    background: var(--gauss-white);
    color: var(--gauss-ink-700);
    font-family: var(--font-body);
    font-size: var(--text-sm);
    font-weight: 600;
    padding: 0.625rem 1.125rem;
    border-radius: var(--radius-pill);
    cursor: pointer;
    box-shadow: 0 1px 3px rgba(11, 18, 32, 0.06);
    transition: transform var(--duration-base) var(--ease-out),
                background-color var(--duration-base) var(--ease-out),
                color var(--duration-base) var(--ease-out),
                box-shadow var(--duration-base) var(--ease-out);
}

.category-pill:hover {
    background: var(--gauss-sky-100);
    transform: translateY(-1px);
}

.category-pill:focus-visible {
    outline: 2px solid var(--color-primary);
    outline-offset: 3px;
}

.category-pill.is-active {
    background: var(--gauss-gradient-brand);
    color: var(--gauss-white);
    box-shadow: 0 8px 22px -6px rgba(21, 88, 160, 0.45);
    transform: translateY(0);
}

/* ============================================================
   3. FEATURED POST
   ============================================================ */
.blog-featured {
    margin-bottom: var(--space-8);
}

.blog-featured__card {
    display: grid;
    grid-template-columns: 1fr;
    background: var(--gauss-white);
    border-radius: var(--radius-bell);
    overflow: hidden;
    box-shadow: 0 16px 40px -10px rgba(11, 18, 32, 0.10);
    transition: transform var(--duration-base) var(--ease-out),
                box-shadow var(--duration-base) var(--ease-out);
}

.blog-featured__card:hover {
    transform: translateY(-3px);
    box-shadow: 0 24px 56px -10px rgba(11, 18, 32, 0.14);
}

.blog-featured__image {
    min-height: 14rem;
}

.blog-featured__content {
    padding: var(--space-5) var(--space-4);
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: var(--space-2);
}

.blog-featured__content h2 {
    font-family: var(--font-brand);
    font-weight: 700;
    font-size: clamp(1.5rem, 2.6vw, 2rem);
    line-height: 1.2;
    color: var(--color-text);
    margin: 0;
}

.blog-featured__content h2 a {
    color: inherit;
    transition: color var(--duration-fast) var(--ease-out);
}

.blog-featured__content h2 a:hover,
.blog-featured__content h2 a:focus-visible {
    color: var(--color-primary);
}

.blog-featured__content p {
    color: var(--gauss-ink-500);
    line-height: 1.65;
    font-size: var(--text-body-lg);
    margin: 0;
}

.blog-featured__meta {
    display: flex;
    align-items: center;
    gap: 0.625rem;
    color: var(--gauss-ink-500);
    font-size: var(--text-xs);
    font-weight: 500;
    margin-top: var(--space-1);
}

.blog-featured__meta .dot {
    width: 3px;
    height: 3px;
    background: currentColor;
    border-radius: 50%;
    opacity: 0.55;
}

@media (min-width: 768px) {
    .blog-featured__card {
        grid-template-columns: 1fr 1fr;
    }
    .blog-featured__image {
        min-height: 19rem;
    }
    .blog-featured__content {
        padding: var(--space-6) var(--space-5);
    }
}

/* ============================================================
   4. CARD GRID
   ============================================================ */
.blog-grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--space-3);
}

@media (min-width: 600px) {
    .blog-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: var(--space-4);
    }
}

@media (min-width: 1000px) {
    .blog-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.blog-card {
    display: flex;
    flex-direction: column;
    background: var(--gauss-white);
    border-radius: var(--radius-bell);
    overflow: hidden;
    box-shadow: 0 4px 16px -4px rgba(11, 18, 32, 0.08);
    transition: transform var(--duration-base) var(--ease-out),
                box-shadow var(--duration-base) var(--ease-out);
}

.blog-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 18px 40px -10px rgba(11, 18, 32, 0.13);
}

.blog-card:focus-within {
    box-shadow: 0 0 0 3px rgba(21, 88, 160, 0.25),
                0 18px 40px -10px rgba(11, 18, 32, 0.13);
}

.blog-card__body {
    padding: var(--space-3);
    display: flex;
    flex-direction: column;
    flex-grow: 1;
    gap: 0.5rem;
}

/* Tag eyebrow */
.blog-card__tag {
    display: inline-block;
    font-family: var(--font-body);
    font-size: 0.6875rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    margin: 0;
}

.tag--fundamentals { color: var(--gauss-blue-700); }
.tag--technology   { color: #1558A0; }
.tag--budgeting    { color: #047857; }
.tag--lifestyle    { color: #BE185D; }

.blog-card h3 {
    font-family: var(--font-brand);
    font-weight: 700;
    font-size: 1.125rem;
    line-height: 1.32;
    color: var(--color-text);
    margin: 0;
    /* clamp to 2 lines for grid rhythm */
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.blog-card h3 a {
    color: inherit;
    transition: color var(--duration-fast) var(--ease-out);
}

.blog-card h3 a:hover,
.blog-card h3 a:focus-visible {
    color: var(--color-primary);
}

.blog-card p {
    color: var(--gauss-ink-500);
    font-size: var(--text-sm);
    line-height: 1.6;
    flex-grow: 1;
    margin: 0;
    /* clamp to 3 lines */
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.blog-card__meta {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--gauss-ink-500);
    font-size: 0.6875rem;
    font-weight: 500;
    margin-top: var(--space-1);
}

.blog-card__meta .dot {
    width: 3px;
    height: 3px;
    background: currentColor;
    border-radius: 50%;
    opacity: 0.55;
}

/* Reveal-on-scroll (added by main.js IntersectionObserver) */
.blog-card.reveal {
    opacity: 0;
    transform: translateY(12px);
    transition: opacity var(--duration-slow) var(--ease-out),
                transform var(--duration-slow) var(--ease-out);
}

.blog-card.reveal.is-visible {
    opacity: 1;
    transform: none;
}

/* JS disabled fallback: show everything */
html.no-js .blog-card.reveal {
    opacity: 1;
    transform: none;
}

@media (prefers-reduced-motion: reduce) {
    .blog-card,
    .blog-card.reveal,
    .blog-featured__card,
    .category-pill {
        transition: none;
    }
    .blog-card.reveal {
        opacity: 1;
        transform: none;
    }
}

/* ============================================================
   5. ARTICLE PAGE (preserved + No-Line Rule applied)
   ============================================================ */
.article {
    padding: calc(var(--header-height) + var(--space-8)) 0 var(--space-12);
}

.article__hero {
    max-width: var(--container-max);
    margin: 0 auto var(--space-6);
    padding: 0 var(--space-4);
}

.article__hero .blog-img {
    border-radius: var(--radius-bell);
    min-height: clamp(200px, 26vw, 340px);
    height: clamp(200px, 26vw, 340px);
}

.article__container {
    max-width: 760px;
    margin: 0 auto;
    padding: 0 var(--space-4);
}

.article__breadcrumbs {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    margin-bottom: var(--space-3);
    flex-wrap: wrap;
}

.article__breadcrumbs a {
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: color var(--duration-fast);
}

.article__breadcrumbs a:hover {
    color: var(--color-primary);
}

.article__breadcrumbs span[aria-hidden] {
    opacity: 0.4;
}

.article__breadcrumb-current {
    color: var(--color-text);
    font-weight: 500;
}

.article__header {
    margin-bottom: var(--space-8);
}

.article__header h1 {
    font-family: var(--font-brand);
    font-weight: 800;
    font-size: clamp(2rem, 4vw, 2.75rem);
    line-height: 1.18;
    letter-spacing: -0.015em;
    margin-bottom: var(--space-3);
}

.article__meta {
    display: flex;
    gap: var(--space-3);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

.article__content h2 {
    font-family: var(--font-brand);
    font-weight: 700;
    font-size: var(--text-h3);
    margin-top: var(--space-8);
    margin-bottom: var(--space-3);
    color: var(--color-text);
}

.article__content h3 {
    font-family: var(--font-brand);
    font-weight: 600;
    font-size: var(--text-body-lg);
    margin-top: var(--space-6);
    margin-bottom: var(--space-2);
    color: var(--color-text);
}

.article__content p {
    margin-bottom: var(--space-3);
    line-height: 1.8;
    color: var(--color-text-secondary);
}

.article__content ul,
.article__content ol {
    margin-bottom: var(--space-3);
    padding-left: var(--space-4);
}

.article__content ul { list-style: disc; }
.article__content ol { list-style: decimal; }

.article__content li {
    padding: 0.3rem 0;
    line-height: 1.7;
    color: var(--color-text-secondary);
}

.article__content a {
    color: var(--color-primary);
    text-decoration: underline;
    text-decoration-color: rgba(21, 88, 160, 0.3);
    text-underline-offset: 2px;
    transition: text-decoration-color var(--duration-fast);
}

.article__content a:hover {
    text-decoration-color: var(--color-primary);
}

.article__content blockquote {
    padding: var(--space-3) var(--space-4);
    margin: var(--space-4) 0;
    background: var(--gauss-sky-100);
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    box-shadow: inset 3px 0 0 var(--color-primary);
}

.article__content blockquote p {
    color: var(--color-text);
    font-weight: 500;
    font-style: italic;
    margin-bottom: 0;
}

.article__content strong {
    color: var(--color-text);
    font-weight: 600;
}

.article__cta {
    background: var(--gauss-sky-100);
    border-radius: var(--radius-bell);
    padding: var(--space-5);
    margin-top: var(--space-8);
    text-align: center;
}

.article__cta h3 {
    margin-bottom: var(--space-2);
}

.article__cta p {
    margin-bottom: var(--space-3);
    color: var(--color-text-secondary);
}

/* Article FAQ section (AEO/GEO) */
.article__faq {
    margin-top: var(--space-8);
    padding-top: var(--space-6);
}

.article__faq h2 {
    font-family: var(--font-brand);
    font-weight: 700;
    font-size: var(--text-h3);
    margin-bottom: var(--space-4);
}

.article__faq details {
    background: var(--gauss-white);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-2);
    box-shadow: 0 1px 3px rgba(11, 18, 32, 0.06);
    transition: box-shadow var(--duration-base) var(--ease-out);
}

.article__faq details[open] {
    box-shadow: 0 6px 20px -4px rgba(11, 18, 32, 0.10);
}

.article__faq summary {
    padding: var(--space-3) var(--space-4);
    cursor: pointer;
    font-weight: 600;
    color: var(--color-text);
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    line-height: 1.5;
}

.article__faq summary::-webkit-details-marker {
    display: none;
}

.article__faq summary::after {
    content: '+';
    font-size: 1.25rem;
    font-weight: 400;
    color: var(--color-text-secondary);
    flex-shrink: 0;
    margin-left: var(--space-2);
    transition: transform var(--duration-fast);
}

.article__faq details[open] summary::after {
    content: '−';
}

.article__faq details p {
    padding: 0 var(--space-4) var(--space-3);
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 0;
}

/* ============================================================
   6. RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
    .blog-listing {
        padding-top: calc(var(--header-height) + var(--space-4));
    }
    .article {
        padding-top: calc(var(--header-height) + var(--space-4));
    }
    .article__meta {
        flex-direction: column;
        gap: var(--space-1);
    }
}