/* =========================================================================
   Debajyoti Gangopadhyay — site stylesheet
   Design tokens live in :root. Change the values here to re-theme the site.
   ========================================================================= */

:root {
  /* Color tokens -- inspired by Nalanda's brick ruins (primary), a night-
     sky indigo standing in for the physics/cosmos side of the author's
     work, and a manuscript gold used sparingly as a hairline accent. */
  --primary-color: #E72800;      /* brand red-orange */
  --primary-color-dark: #A61C00;
  --primary-color-light: #FF4314;
  --primary-tint: #ffe9e573;      /* translucent light tint for backgrounds/badges */
  --indigo-color: #1E2A4A;       /* night-sky indigo */
  --indigo-color-light: #2E3E66;
  --gold-color: #B8892B;         /* manuscript gold-leaf accent */
  --parchment: #EFE8D8;          /* page background */
  --parchment-deep: #E4DAC3;
  --ink: #211D1A;                /* body text */
  --ink-soft: #5B5348;           /* secondary text */
  --surface: #FFFFFF;
  --border-hairline: #D8CBAF;
  --focus-ring: #2E6ADE;

  --font-display: 'Fraunces', Georgia, 'Times New Roman', serif;
  --font-body: 'Source Sans 3', 'Segoe UI', Arial, sans-serif;

  --radius-sm: 6px;
  --radius-md: 14px;
  --radius-lg: 24px;
  --shadow-soft: 0 12px 30px -12px rgba(33, 29, 26, 0.25);
  --shadow-card: 0 6px 18px -8px rgba(33, 29, 26, 0.22);
  --transition-base: 200ms ease;
  --transition-reveal: 600ms cubic-bezier(.22,.9,.32,1);
  --tap-min: 44px; /* Fitts's Law: minimum comfortable touch target */
}

/* =========================== Base & accessibility ===================== */
* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--parchment);
  line-height: 1.65;
  font-size: 1.05rem;
}

h1, h2, h3, h4, .font-display {
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--indigo-color);
  line-height: 1.2;
}

a { color: var(--primary-color); text-decoration-thickness: 1.5px; }
a:hover { color: var(--primary-color-dark); }

img { max-width: 100%; height: auto; display: block; }

/* Visible keyboard focus everywhere, including inside Bootstrap components */
a:focus-visible,
button:focus-visible,
input:focus-visible,
textarea:focus-visible,
select:focus-visible,
.nav-link:focus-visible,
.btn:focus-visible {
  outline: 3px solid var(--focus-ring);
  outline-offset: 3px;
  border-radius: var(--radius-sm);
}

.skip-link {
  position: absolute;
  top: -60px;
  left: 1rem;
  z-index: 2000;
  background: var(--indigo-color);
  color: #fff;
  padding: .6rem 1rem;
  border-radius: var(--radius-sm);
  transition: top var(--transition-base);
}
.skip-link:focus { top: 1rem; color: #fff; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { animation-duration: 0.001ms !important; animation-iteration-count: 1 !important; transition-duration: 0.001ms !important; }
}

.section-eyebrow {
  display: inline-block;
  font-family: var(--font-body);
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  font-size: .78rem;
  color: var(--primary-color);
  margin-bottom: .5rem;
}

.section-pad { padding: 4.5rem 0; }
@media (max-width: 767.98px) { .section-pad { padding: 3rem 0; } }

.divider-thread {
  width: 72px;
  height: 3px;
  background: linear-gradient(90deg, var(--primary-color), var(--gold-color));
  border: none;
  border-radius: 3px;
  margin: 1rem 0 1.75rem;
}

/* =============================== Navbar ================================ */
.site-navbar {
  background: var(--indigo-color);
  padding-top: .65rem;
  padding-bottom: .65rem;
  box-shadow: 0 2px 12px rgba(0,0,0,.15);
}

.navbar-brand { display: flex; align-items: center; gap: .65rem; }

.brand-mark {
  font-family: var(--font-display);
  font-weight: 700;
  background: var(--primary-color);
  color: #fff;
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.05rem;
}

.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-name { font-family: var(--font-display); font-weight: 600; color: #fff; font-size: 1.08rem; }
.brand-role { font-size: .74rem; color: #C9CEDD; letter-spacing: .03em; }

.site-navbar .nav-link {
  color: #E7E9F2;
  font-weight: 600;
  padding: .55rem .9rem !important;
  border-radius: var(--radius-sm);
  transition: background var(--transition-base), color var(--transition-base);
}
.site-navbar .nav-link:hover,
.site-navbar .nav-link:focus-visible { color: #fff; background: rgba(255,255,255,.08); }
.site-navbar .nav-link.active { color: #fff; background: var(--primary-color); }

/* =============================== Buttons ================================ */
.btn-brand {
  background: var(--primary-color);
  border-color: var(--primary-color);
  color: #fff;
  font-weight: 600;
  padding: .7rem 1.6rem;
  border-radius: var(--radius-sm);
  transition: transform var(--transition-base), background var(--transition-base);
}
.btn-brand:hover { background: var(--primary-color-dark); border-color: var(--primary-color-dark); color: #fff; transform: translateY(-2px); }

.btn-outline-brand {
  border: 2px solid var(--surface);
  color: #fff;
  font-weight: 600;
  border-radius: var(--radius-sm);
  padding: .65rem 1.5rem;
}
.btn-outline-brand:hover { background: #fff; color: var(--indigo-color); }

.btn-whatsapp {
  background: #25D366;
  border-color: #25D366;
  color: #fff;
  font-weight: 600;
  border-radius: var(--radius-sm);
}
.btn-whatsapp:hover { background: #1DA851; border-color: #1DA851; color: #fff; }

.btn-amazon {
  background: #131921;
  border-color: #131921;
  color: #FF9900;
  font-weight: 600;
  border-radius: var(--radius-sm);
}
.btn-amazon:hover { background: #232F3E; border-color: #232F3E; color: #FFA928; }

/* =============================== Hero =================================== */
.hero {
  position: relative;
  background: var(--indigo-color);
  color: #fff;
  overflow: hidden;
  padding: 6rem 0 5rem;
}

.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(circle at 12% 20%, rgba(184,137,43,.18), transparent 40%),
    radial-gradient(circle at 88% 78%, rgba(231,40,0,.32), transparent 45%);
  pointer-events: none;
}

.hero-content { position: relative; z-index: 1; }

.hero-eyebrow {
  font-weight: 700;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--gold-color);
  font-size: .82rem;
}

.hero h1 {
  color: #fff;
  font-size: clamp(2.1rem, 4.5vw, 3.4rem);
  margin: .75rem 0 1rem;
}

.hero-tagline {
  font-size: 1.2rem;
  color: #DCE0EE;
  max-width: 640px;
  margin-bottom: 2rem;
}

.hero-portrait-frame {
  border: 3px solid var(--gold-color);
  border-radius: var(--radius-lg);
  padding: 10px;
  background: rgba(255,255,255,.04);
}
.hero-portrait-frame img { border-radius: var(--radius-md); }

/* Dialogue-thread signature: an SVG line strung across the hero,
   representing a dialogue thread between disciplines. Purely decorative. */
.dialogue-thread { position: absolute; inset: 0; z-index: 0; opacity: .35; pointer-events: none; }

/* ===================== Book scroller (home + books page) ================ */
.book-scroller-wrap { position: relative; }

.book-scroller {
  display: flex;
  gap: 1.5rem;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  padding: .75rem .25rem 1.5rem;
  scrollbar-width: thin;
  scrollbar-color: var(--primary-color) var(--parchment-deep);
}
.book-scroller::-webkit-scrollbar { height: 8px; }
.book-scroller::-webkit-scrollbar-track { background: var(--parchment-deep); border-radius: 8px; }
.book-scroller::-webkit-scrollbar-thumb { background: var(--primary-color); border-radius: 8px; }

.book-card {
  flex: 0 0 240px;
  scroll-snap-align: start;
  background: var(--surface);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-card);
  overflow: hidden;
  transition: transform var(--transition-base), box-shadow var(--transition-base);
  display: flex;
  flex-direction: column;
}
.book-card:hover, .book-card:focus-within { transform: translateY(-6px); box-shadow: var(--shadow-soft); }

.book-cover-frame { aspect-ratio: 3 / 4; background: var(--parchment-deep); position: relative; overflow: hidden; }
.book-cover-frame img { width: 100%; height: 100%; object-fit: cover; }
.book-cover-frame .book-cover-fallback {
  position: absolute; inset: 0; display: flex; align-items: center; justify-content: center;
  font-family: var(--font-display); color: var(--ink-soft); text-align: center; padding: 1rem; font-size: .9rem;
}

.book-card-body { padding: 1rem; flex-grow: 1; display: flex; flex-direction: column; }
.book-card-title { font-size: 1rem; margin-bottom: .25rem; }
.book-card-meta { font-size: .82rem; color: var(--ink-soft); margin-bottom: .6rem; }
.book-card-cta { margin-top: auto; }

.scroller-btn {
  position: absolute;
  top: 40%;
  transform: translateY(-50%);
  z-index: 2;
  background: var(--surface);
  border: 1px solid var(--border-hairline);
  width: 42px; height: 42px;
  border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-card);
}
.scroller-btn.prev { left: -14px; }
.scroller-btn.next { right: -14px; }
@media (max-width: 575.98px) { .scroller-btn { display: none; } }

/* =============================== Cards =================================== */
.content-card {
  background: var(--surface);
  border: 1px solid var(--border-hairline);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  height: 100%;
  box-shadow: var(--shadow-card);
  transition: transform var(--transition-base), box-shadow var(--transition-base);
}
.content-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-soft); }

.icon-badge {
  width: 52px; height: 52px;
  border-radius: 50%;
  background: var(--primary-tint);
  color: var(--primary-color);
  display: flex; align-items: center; justify-content: center;
  font-size: 1.3rem;
  margin-bottom: 1rem;
}

/* ===================== Timeline (Teaching / Mission) ===================== */
.thread-timeline { position: relative; padding-left: 2.5rem; }
.thread-timeline::before {
  content: "";
  position: absolute;
  left: 11px; top: 6px; bottom: 6px;
  width: 2px;
  background: linear-gradient(180deg, var(--gold-color), var(--primary-color));
}
.thread-item { position: relative; padding-bottom: 2.25rem; }
.thread-item:last-child { padding-bottom: 0; }
.thread-item::before {
  content: "";
  position: absolute;
  left: -2.5rem;
  top: 4px;
  width: 24px; height: 24px;
  border-radius: 50%;
  background: var(--surface);
  border: 3px solid var(--primary-color);
}

/* ============================ Gallery =================================== */
.gallery-item {
  border-radius: var(--radius-md);
  overflow: hidden;
  position: relative;
  box-shadow: var(--shadow-card);
}
.gallery-item img { aspect-ratio: 4/3; object-fit: cover; transition: transform 400ms ease; }
.gallery-item:hover img { transform: scale(1.06); }
.gallery-caption {
  position: absolute; left: 0; right: 0; bottom: 0;
  background: linear-gradient(180deg, transparent, rgba(30,42,74,.9));
  color: #fff; padding: 1.75rem .9rem .7rem; font-size: .88rem;
}

/* ============================ Blog / Article ============================= */
.article-card { border-left: 4px solid var(--primary-color); }
.article-source-badge {
  display: inline-flex; align-items: center; gap: .35rem;
  background: var(--indigo-color); color: #fff;
  font-size: .74rem; font-weight: 700; letter-spacing: .05em; text-transform: uppercase;
  padding: .25rem .6rem; border-radius: 100px;
}

/* ============================ Forms ======================================= */
.form-control, .form-select {
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-hairline);
  padding: .7rem .9rem;
}
.form-control:focus, .form-select:focus {
  border-color: var(--primary-color);
  box-shadow: 0 0 0 .2rem rgba(231,40,0,.18);
}
label { font-weight: 600; color: var(--indigo-color); }

/* ============================ Footer ======================================= */
.site-footer { background: var(--indigo-color); color: #C9CEDD; padding: 4rem 0 2rem; }
.footer-heading { color: #fff; font-size: 1.05rem; margin-bottom: 1rem; }
.footer-tagline { font-size: .92rem; max-width: 320px; }
.footer-social a {
  display: inline-flex; align-items: center; justify-content: center;
  width: 38px; height: 38px; border-radius: 50%;
  background: rgba(255,255,255,.08); color: #fff; margin-right: .4rem;
  transition: background var(--transition-base);
}
.footer-social a:hover { background: var(--primary-color); }
.footer-links a, .footer-address a { color: #C9CEDD; }
.footer-links a:hover, .footer-address a:hover { color: #fff; }
.footer-links li { margin-bottom: .5rem; }
.footer-address p { margin-bottom: .6rem; font-size: .92rem; }
.footer-divider { border-color: rgba(255,255,255,.15); margin: 2rem 0 1.25rem; }
.footer-bottom { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 1rem; font-size: .85rem; }
.footer-legal a { color: #C9CEDD; }
.footer-legal a:hover { color: #fff; }

.back-to-top {
  position: fixed; right: 1.25rem; bottom: 1.25rem; z-index: 1000;
  width: 46px; height: 46px; border-radius: 50%;
  background: var(--primary-color); color: #fff;
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-soft);
  opacity: 0; visibility: hidden; transform: translateY(10px);
  transition: opacity var(--transition-base), transform var(--transition-base), visibility var(--transition-base);
}
.back-to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }

/* ============================ Utility ===================================== */
.text-primary-brand { color: var(--primary-color) !important; }
.bg-parchment-deep { background: var(--parchment-deep); }
.rounded-lg { border-radius: var(--radius-lg) !important; }

/* =========================================================================
   UX-law upgrades: scroll progress, reveal-on-scroll, toasts, stats bar,
   mobile action bar, breadcrumbs, book filters, FAQ accordion, skeletons.
   ========================================================================= */

/* ---- Visibility of system status: top scroll-progress bar ---- */
.scroll-progress {
  position: fixed; top: 0; left: 0; height: 3px; width: 0%;
  background: linear-gradient(90deg, var(--gold-color), var(--primary-color));
  z-index: 2100; transition: width 80ms linear;
}

/* ---- Jakob's Law: familiar sticky nav, but with a "shrink" state so
   the interface still gives feedback as you scroll (visibility of status) ---- */
.site-navbar { transition: padding var(--transition-base), box-shadow var(--transition-base); position: sticky; top: 0; z-index: 1030; }
.site-navbar.is-shrunk { padding-top: .35rem; padding-bottom: .35rem; }
.site-navbar.is-shrunk .brand-mark { width: 36px; height: 36px; font-size: .92rem; }

/* Comfortable tap targets everywhere interactive (Fitts's Law) */
.site-navbar .nav-link, .btn, .footer-social a, .scroller-btn, .back-to-top, .accordion-button {
  min-height: var(--tap-min);
  display: inline-flex;
  align-items: center;
}
.btn { justify-content: center; }

/* ---- Reveal-on-scroll: content earns attention progressively
   (reduces cognitive load vs. dumping everything at once = Hick's Law) ---- */
[data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity var(--transition-reveal), transform var(--transition-reveal);
}
[data-reveal].is-revealed { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  [data-reveal] { opacity: 1; transform: none; transition: none; }
}

/* ---- Breadcrumbs: Jakob's Law + "you are here" orientation ---- */
.breadcrumb-nav { background: var(--parchment-deep); border-bottom: 1px solid var(--border-hairline); }
.breadcrumb-nav .breadcrumb { margin-bottom: 0; padding: .75rem 0; font-size: .86rem; }
.breadcrumb-nav .breadcrumb-item.active { color: var(--ink-soft); font-weight: 600; }
.breadcrumb-nav .breadcrumb-item a { color: var(--primary-color); font-weight: 600; }

/* ---- Stats bar: credibility / social proof up front (recognition heuristic) ---- */
.stats-bar { background: var(--surface); border-top: 1px solid var(--border-hairline); border-bottom: 1px solid var(--border-hairline); }
.stat-item { text-align: center; padding: 1.75rem .5rem; }
.stat-number { font-family: var(--font-display); font-size: clamp(1.9rem, 4vw, 2.6rem); font-weight: 700; color: var(--primary-color); line-height: 1; }
.stat-label { font-size: .84rem; color: var(--ink-soft); font-weight: 600; letter-spacing: .03em; margin-top: .4rem; }

/* ---- Toasts: feedback for actions (form sent, filters applied) ---- */
.toast-stack { position: fixed; bottom: 1.25rem; right: 1.25rem; z-index: 2200; display: flex; flex-direction: column; gap: .6rem; max-width: min(360px, 90vw); }
.site-toast {
  background: var(--indigo-color); color: #fff; border-radius: var(--radius-sm);
  padding: .9rem 1.1rem; box-shadow: var(--shadow-soft);
  display: flex; align-items: flex-start; gap: .6rem;
  transform: translateY(12px); opacity: 0; transition: transform var(--transition-base), opacity var(--transition-base);
  border-left: 4px solid var(--gold-color);
}
.site-toast.is-visible { transform: translateY(0); opacity: 1; }
.site-toast .toast-icon { color: var(--gold-color); margin-top: 2px; }
.site-toast .toast-close { margin-left: auto; background: none; border: none; color: #C9CEDD; padding: 0; min-height: auto; }
@media (max-width: 575.98px) { .toast-stack { right: .75rem; left: .75rem; max-width: none; } }

/* ---- Mobile bottom action bar: primary actions in thumb reach (Fitts's Law) ---- */
.mobile-action-bar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 1040;
  display: none;
  background: var(--surface); border-top: 1px solid var(--border-hairline);
  box-shadow: 0 -6px 18px -10px rgba(33,29,26,.3);
  padding: .5rem .75rem calc(.5rem + env(safe-area-inset-bottom));
  gap: .5rem;
}
.mobile-action-bar a {
  flex: 1; text-align: center; font-size: .78rem; font-weight: 700;
  color: var(--indigo-color); display: flex; flex-direction: column; align-items: center; gap: .2rem;
  padding: .4rem .2rem; border-radius: var(--radius-sm); min-height: var(--tap-min);
}
.mobile-action-bar a i { font-size: 1.15rem; }
.mobile-action-bar a.primary { background: var(--primary-color); color: #fff; }
@media (max-width: 767.98px) {
  .mobile-action-bar { display: flex; }
  body { padding-bottom: 68px; } /* keep footer content clear of the bar */
  .back-to-top { bottom: 5.25rem; }
}

/* ---- Book filter/search bar (Hick's Law: narrow choices on demand) ---- */
.book-filter-bar {
  background: var(--surface); border: 1px solid var(--border-hairline);
  border-radius: var(--radius-md); padding: 1.25rem; box-shadow: var(--shadow-card);
}
.book-filter-bar .form-label { font-size: .82rem; text-transform: uppercase; letter-spacing: .04em; color: var(--ink-soft); }
.book-empty-state { text-align: center; padding: 3rem 1rem; color: var(--ink-soft); display: none; }
.book-empty-state.is-visible { display: block; }
.filter-result-count { font-size: .88rem; color: var(--ink-soft); }

/* ---- FAQ accordion, themed to match (progressive disclosure) ---- */
.faq-accordion .accordion-item { border: 1px solid var(--border-hairline); border-radius: var(--radius-md) !important; overflow: hidden; margin-bottom: .75rem; }
.faq-accordion .accordion-button { font-family: var(--font-display); font-weight: 600; color: var(--indigo-color); background: var(--surface); }
.faq-accordion .accordion-button:not(.collapsed) { background: var(--parchment-deep); color: var(--primary-color); box-shadow: none; }
.faq-accordion .accordion-button:focus { box-shadow: 0 0 0 .2rem rgba(231,40,0,.18); }

/* ---- Image skeleton shimmer while loading (perceived performance) ---- */
.img-skeleton { position: relative; background: linear-gradient(100deg, var(--parchment-deep) 30%, #f4efe1 50%, var(--parchment-deep) 70%); background-size: 200% 100%; animation: shimmer 1.4s ease-in-out infinite; }
@keyframes shimmer { 0% { background-position: 200% 0; } 100% { background-position: -200% 0; } }
@media (prefers-reduced-motion: reduce) { .img-skeleton { animation: none; } }

/* ---- Live form validation helper text (error prevention heuristic) ---- */
.field-hint { font-size: .8rem; color: var(--ink-soft); margin-top: .25rem; }
.char-counter { font-size: .78rem; color: var(--ink-soft); text-align: right; display: block; margin-top: .25rem; }
.char-counter.is-near-limit { color: var(--primary-color); font-weight: 600; }

.btn-brand[data-loading="true"] { pointer-events: none; opacity: .75; }
.btn-brand .btn-spinner { display: none; width: 16px; height: 16px; border: 2px solid rgba(255,255,255,.5); border-top-color: #fff; border-radius: 50%; animation: spin 700ms linear infinite; margin-right: .5rem; }
.btn-brand[data-loading="true"] .btn-spinner { display: inline-block; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ---- Gallery filter pills ---- */
.gallery-filter-btn {
  border: 1px solid var(--border-hairline); background: var(--surface); color: var(--ink-soft);
  border-radius: 100px; font-weight: 600; padding: .4rem 1rem;
}
.gallery-filter-btn.active, .gallery-filter-btn:hover { background: var(--primary-color); color: #fff; border-color: var(--primary-color); }
.gallery-col.is-hidden { display: none; }



section.hero.hero-deb-section {
    background-image: url(/assets/images/hero-image-bg.png);
}