/* ============================================================
   Learning pages — components for the knowledge hub
   (home, books listing, book summary pages).
   Builds on css/styles.css tokens. See Theme/STUDIO-THEME-GUIDE.md.
   ============================================================ */

/* ============ HOME HERO (centered) ============ */
.hero {
    position: relative; padding: calc(var(--nav-height) + 90px) 0 96px;
    overflow: hidden;
}
.hero-code { max-width: 760px; margin: 0 auto; text-align: center; }

.hero-greeting { font-family: var(--font-mono); color: var(--comment); font-size: 0.95rem; margin-bottom: 14px; }
.hero-title {
    font-family: var(--font-display); font-weight: 800; color: var(--ink);
    font-size: clamp(2.4rem, 7vw, 4.4rem); line-height: 1.05; letter-spacing: -1.5px;
}

/* code-styled typing line: const focus = "…"; */
.hero-typing {
    font-family: var(--font-mono); font-size: clamp(0.95rem, 2.4vw, 1.2rem);
    margin-top: 22px; line-height: 1.5;
}
.tok-kw { color: var(--kw); }
.tok-var { color: var(--var); }
.tok-op { color: var(--ink); }
.tok-str { color: var(--str); }

.hero-sub { margin: 22px auto 0; max-width: 600px; font-size: 1.08rem; color: var(--ink-soft); }
.hero-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 32px; justify-content: center; }

/* ============ COMPACT PAGE HERO ============ */
.page-hero {
    padding: calc(var(--nav-height) + 60px) 0 40px;
    background: radial-gradient(circle at 12% 0%, rgba(37, 99, 235, 0.06), transparent 40%);
}
.page-kicker { font-family: var(--font-mono); color: var(--comment); margin-bottom: 12px; font-size: 0.85rem; }
.page-title {
    font-family: var(--font-display); font-weight: 800;
    font-size: clamp(2.2rem, 6vw, 3.6rem); letter-spacing: -1px; color: var(--ink);
    line-height: 1.05;
}
.page-sub { color: var(--ink-soft); max-width: 660px; margin-top: 16px; font-size: 1.02rem; }
.page-actions { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 28px; }

/* breadcrumb */
.crumbs { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-faint); margin-bottom: 16px; }
.crumbs a { color: var(--ink-soft); transition: color var(--transition); }
.crumbs a:hover { color: var(--accent); }
.crumbs span { margin: 0 6px; color: var(--line-strong); }

/* ============ KNOWLEDGE GRID ============ */
.knowledge-grid {
    display: grid; grid-template-columns: repeat(auto-fill, minmax(320px, 1fr)); gap: 22px;
}

/* ============ CARD (book / course / note / category) ============ */
.k-card {
    position: relative; display: flex; flex-direction: column;
    background: var(--surface); border: 1px solid var(--line);
    border-radius: var(--radius); padding: 26px; overflow: hidden; transition: var(--transition);
}
.k-card::before {
    content: ''; position: absolute; inset: 0 0 auto 0; height: 3px;
    background: var(--grad); background-size: 200% auto; transform: scaleX(0);
    transform-origin: left; transition: transform var(--transition); animation: slideGrad 5s linear infinite;
}
.k-card:hover { transform: translateY(-4px); border-color: var(--accent); box-shadow: 0 14px 34px rgba(20, 30, 60, 0.09); }
.k-card:hover::before { transform: scaleX(1); }

/* a card that is a link */
a.k-card { color: inherit; }

/* placeholder / coming-soon card */
.k-card.is-soon {
    border-style: dashed; border-color: var(--line-strong); background: var(--bg-2);
    align-items: center; justify-content: center; text-align: center; min-height: 240px; color: var(--ink-faint);
}
.k-card.is-soon::before { display: none; }
.k-card.is-soon:hover { transform: none; border-color: var(--accent); box-shadow: none; }
.k-card.is-soon i { font-size: 1.8rem; margin-bottom: 12px; color: var(--ink-faint); }
.k-card.is-soon .k-soon-title { font-family: var(--font-display); font-weight: 700; color: var(--ink-soft); margin-bottom: 6px; font-size: 1.02rem; }
.k-card.is-soon p { font-size: 0.9rem; }

.k-head { display: flex; justify-content: space-between; align-items: flex-start; margin-bottom: 16px; }
.k-icon {
    width: 46px; height: 46px; display: grid; place-items: center; background: var(--bg-2);
    border: 1px solid var(--line); border-radius: var(--radius-sm); color: var(--accent); font-size: 1.15rem;
}

/* status pill */
.k-status {
    font-family: var(--font-mono); font-size: 0.64rem; text-transform: uppercase; letter-spacing: 0.04em;
    font-weight: 700; padding: 5px 11px; border-radius: 999px; border: 1px solid var(--line);
    background: var(--bg-2); color: var(--ink-soft);
}
.k-status.done { color: var(--num); border-color: rgba(10, 158, 110, 0.3); background: rgba(10, 158, 110, 0.08); }
.k-status.reading, .k-status.in-progress { color: var(--var); border-color: rgba(37, 99, 235, 0.3); background: rgba(37, 99, 235, 0.08); }
.k-status.planned { color: var(--kw); border-color: rgba(155, 43, 214, 0.3); background: rgba(155, 43, 214, 0.08); }

.k-title { font-family: var(--font-display); font-weight: 700; font-size: 1.2rem; line-height: 1.3; color: var(--ink); margin-bottom: 6px; }
.k-meta { font-family: var(--font-mono); font-size: 0.74rem; color: var(--ink-faint); margin-bottom: 12px; }
.k-meta i { margin-right: 5px; color: var(--accent); }
.k-desc { color: var(--ink-soft); font-size: 0.92rem; }

/* takeaways */
.k-takeaways { margin: 14px 0 0; padding: 0; }
.k-takeaways li { position: relative; padding-left: 22px; margin-bottom: 8px; color: var(--ink-soft); font-size: 0.9rem; }
.k-takeaways li::before {
    content: '\f0da'; font-family: 'Font Awesome 6 Free'; font-weight: 900;
    position: absolute; left: 0; top: 2px; color: var(--accent); font-size: 0.72rem;
}

/* tags */
.k-tags { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 16px; }
.k-tag {
    font-family: var(--font-mono); font-size: 0.68rem; padding: 4px 10px; background: var(--bg-2);
    color: var(--type); border: 1px solid var(--line); border-radius: 4px;
}

/* rating */
.k-rating { color: var(--fn); font-size: 0.9rem; letter-spacing: 2px; margin-bottom: 12px; }
.k-rating .empty { color: var(--line-strong); }

/* card footer link */
.k-cta {
    margin-top: auto; padding-top: 16px; font-family: var(--font-display); font-weight: 600;
    font-size: 0.85rem; color: var(--accent); display: inline-flex; align-items: center; gap: 8px;
}
.k-card:hover .k-cta i { transform: translateX(4px); }
.k-cta i { transition: transform var(--transition); }

/* progress bar */
.k-progress { height: 8px; background: var(--bg-2); border: 1px solid var(--line); border-radius: 4px; overflow: hidden; margin-top: 14px; }
.k-progress > span { display: block; height: 100%; background: var(--grad); background-size: 200% auto; animation: slideGrad 5s linear infinite; border-radius: 4px; }

/* ============ FEATURED BANNER ============ */
.featured {
    position: relative; display: grid; grid-template-columns: auto 1fr; gap: 28px; align-items: center;
    background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
    padding: 32px; overflow: hidden; transition: var(--transition);
}
.featured::before {
    content: ''; position: absolute; inset: 0 auto 0 0; width: 4px;
    background: var(--grad); background-size: auto 200%; animation: slideGrad 5s linear infinite;
}
.featured:hover { border-color: var(--accent); box-shadow: 0 14px 34px rgba(20, 30, 60, 0.09); }
.featured-cover {
    width: 120px; height: 168px; border-radius: var(--radius-sm);
    background: var(--grad); background-size: 200% auto; animation: slideGrad 6s linear infinite;
    display: grid; place-items: center; color: #fff; font-size: 2.4rem;
    box-shadow: 0 10px 30px rgba(var(--accent-rgb), 0.25);
}
.featured-eyebrow { font-family: var(--font-mono); font-size: 0.76rem; color: var(--comment); margin-bottom: 8px; }
.featured-eyebrow::before { content: '// '; }
.featured-title { font-family: var(--font-display); font-weight: 800; font-size: 1.6rem; color: var(--ink); margin-bottom: 6px; }
.featured-meta { font-family: var(--font-mono); font-size: 0.78rem; color: var(--ink-faint); margin-bottom: 14px; }
.featured-desc { color: var(--ink-soft); margin-bottom: 18px; max-width: 560px; }

@media (max-width: 640px) {
    .featured { grid-template-columns: 1fr; text-align: center; justify-items: center; }
    .featured::before { width: 100%; height: 4px; inset: 0 0 auto 0; }
}

/* ============ BOOK PAGE LAYOUT (TOC + content) ============ */
.book-layout {
    display: grid; grid-template-columns: 240px 1fr; gap: 48px;
    max-width: 1080px; margin: 0 auto; align-items: start;
}

/* sticky chapter TOC */
.toc { position: sticky; top: calc(var(--nav-height) + 24px); }
.toc-label {
    font-family: var(--font-mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.08em;
    color: var(--ink-faint); margin-bottom: 14px; padding-left: 14px;
}
.toc-list { border-left: 2px solid var(--line); }
.toc-list a {
    display: block; padding: 7px 0 7px 14px; margin-left: -2px;
    border-left: 2px solid transparent; font-family: var(--font-mono); font-size: 0.82rem;
    color: var(--ink-soft); line-height: 1.4; transition: var(--transition);
}
.toc-list a:hover { color: var(--ink); }
.toc-list a.active { color: var(--accent); border-left-color: var(--accent); font-weight: 600; }
.toc-num { color: var(--ink-faint); margin-right: 8px; }
.toc-list a.active .toc-num { color: var(--accent); }

/* ============ BOOK HERO WITH COVER ============ */
.book-hero-inner {
    display: grid; grid-template-columns: 1fr auto; gap: 44px; align-items: start;
}
.book-hero-main { min-width: 0; }
.book-hero-cover { position: static; }
.book-cover {
    width: 300px; border-radius: var(--radius); overflow: hidden;
    border: 1px solid var(--line-strong); background: var(--surface);
    box-shadow: 0 24px 50px rgba(20, 30, 60, 0.18);
}
.book-cover img { width: 100%; height: auto; display: block; }

@media (max-width: 820px) {
    .book-hero-inner { grid-template-columns: 1fr; }
    .book-hero-cover { position: static; order: -1; justify-self: start; }
    .book-cover { width: 200px; }
}

/* ============ READER (chapter carousel) ============ */
.reader { min-width: 0; max-width: 700px; }
.reader-viewport.prose { max-width: none; }
.reader-bar {
    position: static;
    display: flex; align-items: center; justify-content: space-between; gap: 12px;
    background: var(--surface); border: 1px solid var(--line);
    border-radius: var(--radius); padding: 10px 12px; margin-bottom: 26px;
    box-shadow: 0 6px 20px rgba(20, 30, 60, 0.05);
}
.reader-nav {
    flex: 0 0 auto; width: 40px; height: 40px; display: grid; place-items: center;
    background: var(--bg-2); border: 1px solid var(--line); border-radius: var(--radius-sm);
    color: var(--ink); cursor: pointer; transition: var(--transition);
}
.reader-nav:hover:not(:disabled) { background: var(--accent); border-color: var(--accent); color: #fff; }
.reader-nav:disabled { opacity: 0.4; cursor: not-allowed; }
.reader-status { text-align: center; min-width: 0; }
.reader-count { display: block; font-family: var(--font-mono); font-size: 0.7rem; color: var(--accent); letter-spacing: 0.05em; }
.reader-now {
    display: block; font-family: var(--font-display); font-weight: 700; color: var(--ink);
    font-size: 0.95rem; white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
}

/* the viewport also carries .prose typography */
.reader-viewport { position: relative; }
.reader-viewport .chapter-slide { display: none; border-bottom: none; padding-bottom: 8px; margin-bottom: 0; }
.reader-viewport .chapter-slide.is-active { display: block; }
.reader-viewport .chapter-slide.is-active.dir-next { animation: chapNext 0.4s cubic-bezier(0.16, 1, 0.3, 1); }
.reader-viewport .chapter-slide.is-active.dir-prev { animation: chapPrev 0.4s cubic-bezier(0.16, 1, 0.3, 1); }

@keyframes chapNext { from { opacity: 0; transform: translateX(30px); } to { opacity: 1; transform: none; } }
@keyframes chapPrev { from { opacity: 0; transform: translateX(-30px); } to { opacity: 1; transform: none; } }

.reader-foot {
    display: flex; align-items: center; justify-content: space-between; gap: 16px;
    margin-top: 26px; padding-top: 22px; border-top: 1px solid var(--line);
}
.reader-foot .btn { flex: 0 0 auto; }
.reader-step:disabled { opacity: 0.4; cursor: not-allowed; transform: none; box-shadow: none; pointer-events: none; }
.reader-dots { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; flex: 1 1 auto; }
.reader-dots button {
    width: 9px; height: 9px; padding: 0; border-radius: 50%; cursor: pointer;
    background: var(--line-strong); border: none; transition: var(--transition);
}
.reader-dots button:hover { background: var(--ink-faint); transform: scale(1.2); }
.reader-dots button.is-active {
    width: 22px; border-radius: 5px;
    background: var(--grad); background-size: 200% auto; animation: slideGrad 5s linear infinite;
}

@media (max-width: 560px) {
    .reader-foot { flex-wrap: wrap; }
    .reader-dots { order: 3; flex-basis: 100%; margin-top: 6px; }
    .reader-now { font-size: 0.85rem; }
}

/* ============ PROSE (long summaries / notes) ============ */
.prose { max-width: 72ch; font-family: var(--font-body); color: var(--ink-soft); line-height: 1.85; font-size: 1.02rem; }
.prose > section { padding-top: 12px; margin-bottom: 30px; border-bottom: 1px solid var(--line); padding-bottom: 34px; }
.prose > section:last-child { border-bottom: none; }
.chapter-eyebrow { font-family: var(--font-mono); font-size: 0.76rem; color: var(--comment); margin-bottom: 8px; }
.prose h2 {
    font-family: var(--font-display); color: var(--ink); font-size: 1.7rem; margin: 6px 0 18px;
    line-height: 1.2; letter-spacing: -0.5px; position: relative; padding-left: 16px;
}
.prose h2::before {
    content: ''; position: absolute; left: 0; top: 0.12em; bottom: 0.12em; width: 4px;
    border-radius: 4px; background: var(--grad); background-size: 200% auto; animation: slideGrad 6s linear infinite;
}
.prose h3 { font-family: var(--font-display); color: var(--ink); font-size: 1.2rem; margin: 30px 0 12px; }
.prose h4 { font-family: var(--font-display); color: var(--ink); font-size: 1rem; margin: 22px 0 8px; }
.prose p { margin-bottom: 16px; }
.prose strong { color: var(--var); font-weight: 600; }
.prose em { color: var(--ink); }
.prose a { color: var(--accent); text-decoration: underline; text-underline-offset: 3px; }
.prose ul, .prose ol { margin: 0 0 16px 22px; }
.prose ul { list-style: disc; }
.prose ol { list-style: decimal; }
.prose li { margin-bottom: 8px; }
.prose li::marker { color: var(--accent); }
.prose code {
    font-family: var(--font-mono); font-size: 0.88em; background: var(--bg-2);
    border: 1px solid var(--line); padding: 2px 6px; border-radius: 4px; color: var(--str);
}
.prose blockquote {
    border-left: 3px solid var(--accent); background: var(--bg-2); padding: 16px 20px;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0; margin: 22px 0; color: var(--ink); font-style: italic;
    font-family: var(--font-body);
}

/* ============ TABLE (good vs bad questions etc.) ============ */
.prose table {
    width: 100%; border-collapse: collapse; margin: 20px 0; font-size: 0.9rem;
    border: 1px solid var(--line); border-radius: var(--radius-sm); overflow: hidden;
}
.prose th, .prose td { text-align: left; padding: 11px 14px; border-bottom: 1px solid var(--line); vertical-align: top; }
.prose th {
    background: var(--chrome); font-family: var(--font-display); font-weight: 700;
    color: var(--ink); font-size: 0.82rem;
}
.prose tr:last-child td { border-bottom: none; }
.prose tbody tr:hover { background: var(--bg-2); }

/* ============ CALLOUTS (Obsidian-style admonitions) ============ */
.callout {
    position: relative; margin: 20px 0; padding: 16px 18px 16px 48px;
    border: 1px solid var(--line); border-left-width: 3px; border-radius: var(--radius-sm);
    background: var(--bg-2); color: var(--ink); font-style: normal;
}
.callout::before {
    position: absolute; left: 16px; top: 17px; font-family: 'Font Awesome 6 Free'; font-weight: 900;
    font-size: 0.95rem;
}
.callout-title {
    font-family: var(--font-display); font-weight: 700; font-size: 0.82rem;
    text-transform: uppercase; letter-spacing: 0.04em; margin-bottom: 6px; display: block;
}
.callout p:last-child { margin-bottom: 0; }
.callout p { margin-bottom: 10px; }
.callout ol, .callout ul { margin: 6px 0 0 18px; }
.callout li { margin-bottom: 6px; }

/* quote / core idea — blue */
.callout.quote { border-left-color: var(--var); background: rgba(37, 99, 235, 0.05); }
.callout.quote::before { content: '\f10d'; color: var(--var); }
.callout.quote .callout-title { color: var(--var); }

/* warning / trap — red */
.callout.warning { border-left-color: var(--str); background: rgba(192, 57, 43, 0.05); }
.callout.warning::before { content: '\f071'; color: var(--str); }
.callout.warning .callout-title { color: var(--str); }

/* important — purple */
.callout.important { border-left-color: var(--kw); background: rgba(155, 43, 214, 0.05); }
.callout.important::before { content: '\f0eb'; color: var(--kw); }
.callout.important .callout-title { color: var(--kw); }

/* example — green */
.callout.example { border-left-color: var(--num); background: rgba(10, 158, 110, 0.05); }
.callout.example::before { content: '\f0c3'; color: var(--num); }
.callout.example .callout-title { color: var(--num); }

/* ============ TAKEAWAYS / RULES BOXES ============ */
.box {
    background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
    padding: 22px 24px; margin: 24px 0;
}
.box-title {
    font-family: var(--font-display); font-weight: 700; color: var(--ink); font-size: 1rem;
    display: flex; align-items: center; gap: 9px; margin-bottom: 14px;
}
.box-title i { color: var(--accent); }
.box ol, .box ul { margin: 0 0 0 4px; list-style: none; }
.box li { position: relative; padding-left: 28px; margin-bottom: 10px; font-size: 0.92rem; color: var(--ink-soft); line-height: 1.6; }
.box.takeaways ol { counter-reset: item; }
.box.takeaways li::before {
    content: counter(item); counter-increment: item;
    position: absolute; left: 0; top: 1px; width: 19px; height: 19px;
    background: rgba(var(--accent-rgb), 0.1); color: var(--accent); border-radius: 4px;
    font-family: var(--font-mono); font-size: 0.66rem; font-weight: 700;
    display: grid; place-items: center;
}
.box.rules li::before {
    content: '\f0a4'; font-family: 'Font Awesome 6 Free'; font-weight: 900;
    position: absolute; left: 0; top: 2px; color: var(--fn); font-size: 0.8rem;
}

/* ============ CHAPTER NAV (anchor offset) ============ */
.section-anchor { scroll-margin-top: calc(var(--nav-height) + 20px); }

/* ============ CTA STRIP ============ */
.cta-strip {
    background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
    padding: 36px; text-align: center; margin-top: 44px; position: relative; overflow: hidden;
}
.cta-strip::before {
    content: ''; position: absolute; inset: 0 0 auto 0; height: 4px;
    background: var(--grad); background-size: 200% auto; animation: slideGrad 5s linear infinite;
}
.cta-strip h3 { font-family: var(--font-display); color: var(--ink); font-size: 1.4rem; margin-bottom: 10px; }
.cta-strip p { color: var(--ink-soft); max-width: 520px; margin: 0 auto 22px; }

/* ============ RESPONSIVE ============ */
@media (max-width: 900px) {
    .book-layout { grid-template-columns: 1fr; gap: 24px; }
    .toc {
        position: static; background: var(--bg-2); border: 1px solid var(--line);
        border-radius: var(--radius-sm); padding: 16px 18px;
    }
    .toc-list { max-height: none; }
}
@media (max-width: 768px) {
    .knowledge-grid { grid-template-columns: 1fr; }
    .page-hero { padding-top: calc(var(--nav-height) + 40px); }
    .prose { max-width: 100%; }
    .hero { padding: calc(var(--nav-height) + 56px) 0 64px; }
}
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: 0.001ms !important; animation-iteration-count: 1 !important;
        transition-duration: 0.001ms !important;
    }
}