/* ============================================================
   NAC OSCE — A Comprehensive Review
   Premium editorial-medical textbook aesthetic
   ============================================================ */

:root {
  /* Surfaces — warmed cream paper, deliberately tinted toward brand */
  --bg:        #FAF7F1;
  --bg-alt:    #EFEAE0;
  --paper:     #FFFCF6;          /* highest surface (cards on bg-alt sections) */

  /* Ink — warm near-black, never pure */
  --ink:       #16110F;
  --ink-soft:  #3B342F;
  --muted:     #5F5852;
  --rule:      #CFC9BC;

  /* Primary accent — deepened oxblood (voice, action) */
  --accent:    #7A1E2D;
  --accent-ink:#5A1320;
  --accent-bg: #F4E4DE;          /* tinted wash for subtle highlights */

  /* Secondary accent — academic navy (structure, index, scholarship) */
  --accent-2:     #1F3148;
  --accent-2-ink: #14213A;

  --focus:     #7A1E2D;

  --serif: "Fraunces", Georgia, "Times New Roman", serif;
  --sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  --container: 1180px;
  --measure:   680px;
  --radius:    2px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: "kern", "liga", "calt";
}

img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }

/* --- Focus ring (accessibility) --- */
:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 3px;
  border-radius: 2px;
}
.btn:focus-visible { outline-offset: 3px; }
.form input:focus-visible,
.form textarea:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
  border-color: var(--accent);
}

/* --- Skip link --- */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 8px;
  background: var(--ink);
  color: #F5EFE6;
  padding: 10px 16px;
  font-size: .9rem;
  font-weight: 500;
  border-radius: 2px;
  z-index: 100;
}
.skip-link:focus {
  left: 16px;
  color: #F5EFE6;
  text-decoration: none;
}

/* --- Typography --- */
h1, h2, h3, h4 {
  font-family: var(--serif);
  font-weight: 600;
  color: var(--ink);
  letter-spacing: -0.01em;
  margin: 0 0 .5em;
  font-variation-settings: "opsz" 36, "SOFT" 50;
}
h1 { font-size: clamp(2.4rem, 4.2vw, 3.6rem); line-height: 1.08; letter-spacing: -0.02em; text-wrap: balance; }
h2 { font-size: clamp(1.7rem, 2.6vw, 2.2rem); line-height: 1.15; text-wrap: balance; }
h3 { font-size: 1.2rem; line-height: 1.3; text-wrap: balance; }

p { margin: 0 0 1em; color: var(--ink-soft); max-width: var(--measure); text-wrap: pretty; }
.lead { font-size: 1.18rem; color: var(--ink); max-width: 60ch; }
.eyebrow {
  font-family: var(--sans);
  font-size: .78rem;
  font-weight: 500;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent);
  display: inline-block;
  margin-bottom: 1rem;
}

/* --- Layout --- */
.container { max-width: var(--container); margin: 0 auto; padding: 0 32px; }
.section { padding: 96px 0; }
.section + .section { border-top: 1px solid var(--rule); }
.section-title { max-width: 640px; margin-bottom: 56px; }

hr.rule { border: 0; border-top: 1px solid var(--rule); margin: 0; }

/* --- Nav --- */
.nav {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in oklab, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid transparent;
  box-shadow: 0 1px 0 var(--rule);
  transition: box-shadow .25s ease;
}
.nav.scrolled {
  box-shadow:
    0 1px 0 var(--rule),
    0 8px 24px -16px rgba(20, 12, 10, 0.18);
}
.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 16px 32px;
  display: flex; align-items: center; justify-content: space-between;
  gap: 32px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  flex-shrink: 0;
  white-space: nowrap;
  color: var(--ink);
}
.brand:hover { text-decoration: none; color: var(--ink); }
.brand-mark {
  width: 60px;
  height: 60px;
  flex-shrink: 0;
  object-fit: contain;
  display: block;
}
.brand-text {
  display: inline-flex;
  flex-direction: column;
  gap: 3px;
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.08rem;
  letter-spacing: -0.01em;
  line-height: 1.05;
}
.brand-text small {
  font-family: var(--sans);
  font-size: .66rem;
  font-weight: 500;
  color: var(--accent-2);
  letter-spacing: .16em;
  text-transform: uppercase;
  white-space: nowrap;
}

.nav-links {
  display: flex;
  gap: 32px;
  align-items: center;
}
.nav-links a:not(.btn) {
  font-size: .92rem;
  color: var(--ink-soft);
  font-weight: 500;
  position: relative;
  padding: 6px 0;
  transition: color .15s ease;
}
.nav-links a:not(.btn):hover {
  color: var(--ink);
  text-decoration: none;
}
.nav-links a:not(.btn)::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 2px;
  height: 1.5px;
  background: var(--accent);
  transform: scaleX(0);
  transform-origin: left center;
  transition: transform .25s ease;
}
.nav-links a:not(.btn):hover::after { transform: scaleX(.4); }
.nav-links a.active:not(.btn) { color: var(--ink); }
.nav-links a.active:not(.btn)::after {
  transform: scaleX(1);
  background: var(--accent);
  height: 2px;
}

/* Nav CTA button: tighter padding to match link rhythm, always white text */
.nav-links a.btn-primary,
.nav-links a.btn-primary:hover,
.nav-links a.btn-primary:visited,
.nav-links a.btn-primary.active { color: #fff; }
.nav-links a.nav-cta {
  padding: 9px 18px;
  font-size: .9rem;
  margin-left: 8px;
}

/* --- Buttons --- */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 8px;
  padding: 13px 22px;
  font-family: var(--sans);
  font-size: .95rem;
  font-weight: 500;
  letter-spacing: .01em;
  border-radius: var(--radius);
  border: 1px solid transparent;
  transition: all .18s ease;
  cursor: pointer;
  white-space: nowrap;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-ink); color: #fff; text-decoration: none; }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--ink); }
.btn-ghost:hover { background: var(--ink); color: #fff; text-decoration: none; }
.btn-link {
  font-size: .95rem; font-weight: 500; color: var(--ink);
  border-bottom: 1px solid var(--ink);
  padding-bottom: 2px;
}
.btn-link:hover { color: var(--accent); border-color: var(--accent); text-decoration: none; }
.btn-link::after { content: " →"; }

/* --- Hero --- */
.hero { padding: 120px 0 96px; }
.hero-grid {
  display: grid;
  grid-template-columns: 1.15fr .85fr;
  gap: 80px;
  align-items: center;
}
.hero h1 { margin-bottom: 24px; }
.hero .lead { margin-bottom: 36px; color: var(--ink-soft); }
.hero-ctas { display: flex; gap: 14px; flex-wrap: wrap; }
.hero-meta {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--rule);
  display: flex; gap: 40px; flex-wrap: wrap;
}
.hero-meta div { font-size: .85rem; color: var(--muted); }
.hero-meta strong { display: block; color: var(--ink); font-size: 1.1rem; font-family: var(--serif); font-weight: 600; }

/* --- Book Cover --- */
.cover-wrap {
  perspective: 1400px;
  display: flex;
  justify-content: center;
}
.cover-img {
  width: 320px;
  height: auto;
  border-radius: 2px 4px 4px 2px;
  box-shadow:
    0 30px 60px -20px rgba(20, 10, 15, 0.55),
    0 20px 40px -10px rgba(20, 10, 15, 0.35);
  transform: rotateY(-14deg) rotateX(2deg);
  transform-style: preserve-3d;
  transition: transform .6s ease;
  display: block;
}
.cover-img:hover { transform: rotateY(-6deg) rotateX(1deg); }

/* --- Value Props Grid --- */
.values {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1px;
  background: var(--rule);
  border: 1px solid var(--rule);
}
.value {
  background: var(--bg);
  padding: 40px 36px;
  transition: background .2s ease;
}
.value:hover { background: var(--bg-alt); }
.value-num {
  font-family: var(--serif);
  font-size: 1rem;
  color: var(--accent-2);
  margin-bottom: 18px;
  letter-spacing: .05em;
}
.value h3 { margin-bottom: 10px; }
.value p { font-size: .95rem; margin: 0; color: var(--ink-soft); }

/* --- Chapter Cards --- */
.chapters {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
  background: var(--rule);
  border: 1px solid var(--rule);
}
.chapter {
  background: var(--bg);
  padding: 32px 28px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: background .2s ease;
}
.chapter:hover { background: var(--bg-alt); }
.chapter-num {
  font-family: var(--serif);
  font-size: .85rem;
  color: var(--accent-2);
  letter-spacing: .08em;
  font-weight: 600;
}
.chapter h3 { font-size: 1.1rem; margin: 0; }
.chapter p { font-size: .9rem; margin: 4px 0 0; color: var(--muted); }

/* --- CTA Band --- */
.cta-band {
  background: var(--accent-2-ink);
  color: #F5EFE6;
  padding: 88px 0;
  text-align: center;
}
.cta-band h2 { color: #F5EFE6; margin-bottom: 16px; }
.cta-band p {
  color: rgba(245, 239, 230, .75);
  max-width: 520px;
  margin: 0 auto 32px;
}
.cta-band .btn-primary { background: var(--accent); }
.cta-band .btn-primary:hover { background: #8A2937; }
.cta-band .btn-ghost { color: #F5EFE6; border-color: rgba(245,239,230,.4); }
.cta-band .btn-ghost:hover { background: #F5EFE6; color: var(--ink); }

/* --- Testimonial --- */
.quote {
  max-width: 800px;
  margin: 0 auto;
  text-align: center;
  font-family: var(--serif);
  font-style: italic;
  font-size: clamp(1.3rem, 2.2vw, 1.7rem);
  line-height: 1.4;
  color: var(--ink);
}
.quote::before, .quote::after {
  content: "";
  display: block;
  height: 1px; width: 48px;
  background: var(--accent);
  margin: 24px auto;
}
.quote-cite {
  font-family: var(--sans);
  font-style: normal;
  font-size: .85rem;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: var(--muted);
}

/* --- Footer --- */
.footer {
  background: var(--bg-alt);
  padding: 64px 0 40px;
  border-top: 1px solid var(--rule);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}
.footer h4 {
  font-family: var(--sans);
  font-size: .75rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 16px;
  font-weight: 500;
}
.footer ul { list-style: none; padding: 0; margin: 0; }
.footer li { margin-bottom: 10px; }
.footer a { color: var(--ink-soft); font-size: .92rem; }
.footer a:hover { color: var(--accent); }
.footer-brand { font-family: var(--serif); font-size: 1.2rem; margin-bottom: 12px; color: var(--ink); }
.footer-about p { font-size: .92rem; color: var(--muted); max-width: 34ch; }
.footer-bottom {
  display: flex; justify-content: space-between; align-items: center;
  padding-top: 24px; border-top: 1px solid var(--rule);
  font-size: .82rem; color: var(--muted);
  flex-wrap: wrap; gap: 12px;
}

/* --- Long-form (sample, about) --- */
.longform { max-width: var(--measure); margin: 0 auto; }
.longform p { font-size: 1.05rem; line-height: 1.75; }
.longform h2 { margin-top: 2em; }
.longform h3 { margin-top: 1.6em; }
.longform ul, .longform ol { color: var(--ink-soft); line-height: 1.7; padding-left: 1.2em; }
.longform li { margin-bottom: .4em; }
.longform blockquote {
  margin: 2.4em 0;
  padding: 0 0 0 1.2em;
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.2rem;
  line-height: 1.5;
  color: var(--ink);
  position: relative;
  text-indent: -.4em;
}
.longform blockquote::before {
  content: "\201C";
  font-family: var(--serif);
  font-style: normal;
  font-size: 2.2em;
  line-height: 1;
  color: var(--accent);
  position: absolute;
  left: 0;
  top: -.05em;
}

/* --- Sample PDF viewer --- */
.pdf-frame {
  width: 100%;
  height: 85vh;
  min-height: 640px;
  border: 1px solid var(--rule);
  background: #fff;
  border-radius: var(--radius);
}

/* --- Contact form --- */
.form { max-width: 560px; margin: 0 auto; }
.form label {
  display: block;
  font-size: .8rem;
  font-weight: 500;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 8px;
  margin-top: 24px;
}
.form input, .form textarea {
  width: 100%;
  padding: 12px 14px;
  font-family: var(--sans);
  font-size: 1rem;
  background: #fff;
  color: var(--ink);
  border: 1px solid var(--rule);
  border-radius: var(--radius);
  transition: border-color .15s ease;
}
.form input:focus, .form textarea:focus {
  outline: none;
  border-color: var(--accent);
}
.form textarea { min-height: 140px; resize: vertical; }
.form button { margin-top: 28px; }

/* --- Mobile nav toggle (hamburger) --- */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px 4px;
  flex-shrink: 0;
  -webkit-tap-highlight-color: transparent;
}
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--ink);
  border-radius: 1px;
  transition: transform .25s ease, opacity .2s ease;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- Responsive --- */
@media (max-width: 900px) {
  .hero { padding: 72px 0 56px; }
  .hero-grid { grid-template-columns: 1fr; gap: 56px; }
  .cover-wrap { order: -1; }
  .cover-img { transform: rotateY(-8deg); width: 240px; }
  .section { padding: 64px 0; }
  .values { grid-template-columns: 1fr; }
  .chapters { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 32px; }
  .nav-links { gap: 18px; }
  .nav-links a { font-size: .85rem; }
  .hero-meta { gap: 24px; }
}
@media (max-width: 640px) {
  html { overflow-x: hidden; }
  body { overflow-x: hidden; }
  .container { padding: 0 20px; }
  .nav-inner { padding: 14px 20px; }

  /* Show hamburger button */
  .nav-toggle { display: flex; }

  /* Collapse nav links into a dropdown */
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    gap: 0;
    background: var(--bg);
    border-bottom: 2px solid var(--rule);
    box-shadow: 0 8px 24px -8px rgba(20,12,10,.18);
    padding: 4px 20px 20px;
  }
  .nav-links.open { display: flex; }

  /* All links visible inside the dropdown */
  .nav-links a:not(.btn) {
    display: block;
    font-size: 1rem;
    padding: 13px 0;
    border-bottom: 1px solid var(--rule);
    color: var(--ink-soft);
  }
  .nav-links a:not(.btn):last-of-type { border-bottom: none; }
  .nav-links a:not(.btn)::after { display: none; }
  .nav-links a.active:not(.btn) { color: var(--accent); }

  /* CTA button full width at bottom of dropdown */
  .nav-links .nav-cta {
    display: flex;
    width: 100%;
    justify-content: center;
    margin: 12px 0 0;
  }

  .chapters { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
  .hero-ctas .btn { width: 100%; }
  .hero-ctas { gap: 10px; }
}

/* --- Reduced motion --- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .01ms !important;
    scroll-behavior: auto !important;
  }
  .cover-img { transform: none; }
  .cover-img:hover { transform: none; }
}