/* ==========================================================================
   VAYUANTRIKSH — Publications Catalogue
   Design language: aerospace technical-document plates (matches the
   navy/gold system used across vayuantriksh.in). Book covers are treated
   as dossier plates: doc numbers, rev stamps, corner brackets.
   ========================================================================== */

:root{
  --navy-deep:   #0b1b2e;
  --navy-mid:    #12293f;
  --navy-line:   rgba(198, 161, 91, 0.28);
  --gold:        #c6a15b;
  --gold-bright: #e4c883;
  --gold-dim:    rgba(198, 161, 91, 0.14);
  --paper:       #f3efe4;
  --paper-dim:   #e8e1cd;
  --ink:         #1b2230;
  --slate:       #5c6b80;
  --slate-light: #8695a8;

  --font-display: 'Oswald', 'Arial Narrow', sans-serif;
  --font-body:    'Source Serif 4', Georgia, serif;
  --font-mono:    'JetBrains Mono', 'Courier New', monospace;

  --maxw: 1180px;
}

*{ box-sizing:border-box; }
html{ scroll-behavior:smooth; }
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--font-body);
  line-height:1.55;
  -webkit-font-smoothing:antialiased;
}
img{ max-width:100%; display:block; }
a{ color:inherit; }

.doc-tag{
  font-family:var(--font-mono);
  font-size:0.72rem;
  letter-spacing:0.12em;
  text-transform:uppercase;
  color:var(--gold);
  margin:0 0 0.6em;
}

/* ---------- decorative top skyband ---------- */
.skyband{
  height:4px;
  background:linear-gradient(90deg, var(--navy-deep) 0%, var(--gold) 50%, var(--navy-deep) 100%);
}

/* ---------- header ---------- */
.site-header{
  background:var(--navy-deep);
  color:var(--paper);
  position:sticky;
  top:0;
  z-index:40;
  border-bottom:1px solid var(--navy-line);
}
.site-header__inner{
  max-width:var(--maxw);
  margin:0 auto;
  padding:0.85rem 1.5rem;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:1.5rem;
}
.brand{
  display:flex;
  align-items:center;
  gap:0.7rem;
  text-decoration:none;
  color:var(--gold);
}
.brand__mark{ width:30px; height:30px; flex-shrink:0; }
.brand__type{ display:flex; flex-direction:column; line-height:1.1; }
.brand__name{
  font-family:var(--font-display);
  font-weight:600;
  letter-spacing:0.06em;
  font-size:1.02rem;
  color:var(--paper);
}
.brand__sub{
  font-family:var(--font-mono);
  font-size:0.62rem;
  letter-spacing:0.1em;
  text-transform:uppercase;
  color:var(--gold);
}
.site-nav{
  display:flex;
  flex-wrap:wrap;
  gap:0.3rem;
  justify-content:flex-end;
}
.site-nav a{
  font-family:var(--font-mono);
  font-size:0.7rem;
  letter-spacing:0.05em;
  text-transform:uppercase;
  text-decoration:none;
  color:var(--slate-light);
  padding:0.4rem 0.6rem;
  border:1px solid transparent;
  border-radius:2px;
  white-space:nowrap;
  transition:color 0.15s ease, border-color 0.15s ease;
}
.site-nav a:hover,
.site-nav a:focus-visible{
  color:var(--gold-bright);
  border-color:var(--navy-line);
  outline:none;
}

/* ---------- hero ---------- */
.hero{
  position:relative;
  background:
    radial-gradient(ellipse 900px 400px at 15% -10%, rgba(198,161,91,0.16), transparent 60%),
    var(--navy-deep);
  color:var(--paper);
  overflow:hidden;
  padding:4.5rem 1.5rem 3.5rem;
}
.hero__grid{
  position:absolute; inset:0;
  background-image:
    linear-gradient(var(--navy-line) 1px, transparent 1px),
    linear-gradient(90deg, var(--navy-line) 1px, transparent 1px);
  background-size:44px 44px;
  opacity:0.35;
  mask-image:linear-gradient(180deg, black, transparent 85%);
}
.hero__inner{
  position:relative;
  max-width:var(--maxw);
  margin:0 auto;
}
.hero__title{
  font-family:var(--font-display);
  font-weight:700;
  font-size:clamp(2.6rem, 6vw, 4.4rem);
  letter-spacing:0.01em;
  margin:0 0 0.9rem;
  color:var(--paper);
}
.hero__lede{
  max-width:640px;
  font-size:1.08rem;
  color:#cdd6e2;
  margin:0 0 1.6rem;
}
.hero__meta{
  font-family:var(--font-mono);
  font-size:0.78rem;
  color:var(--gold-bright);
  display:flex;
  align-items:center;
  gap:0.6rem;
}
.hero__meta em{ font-style:normal; color:#aebcce; }
.hero__meta-div{ color:var(--navy-line); }

/* ---------- catalogue loading / error / empty states ---------- */
.catalogue-state{
  max-width:var(--maxw);
  margin:0 auto;
  padding:3rem 1.5rem;
  font-family:var(--font-mono);
  font-size:0.85rem;
  color:var(--slate);
  text-align:center;
}
.catalogue-state code{
  background:var(--paper-dim);
  padding:0.1rem 0.35rem;
  border-radius:2px;
}
.catalogue-state--error{ color:#a33; }
.link-btn{
  background:none; border:none; padding:0;
  font-family:inherit; font-size:inherit;
  color:var(--gold); text-decoration:underline;
  cursor:pointer;
}

/* ---------- catalogue sections ---------- */
#catalogue{ max-width:var(--maxw); margin:0 auto; padding:0 1.5rem; }

.section{ padding:3.4rem 0; border-top:1px solid var(--paper-dim); }
.section:first-child{ border-top:none; padding-top:3.8rem; }

.section__head{
  display:flex;
  align-items:baseline;
  gap:0.9rem;
  margin-bottom:1.9rem;
  flex-wrap:wrap;
}
.section__code{
  font-family:var(--font-mono);
  font-size:0.75rem;
  color:var(--gold);
  border:1px solid var(--gold);
  padding:0.15rem 0.5rem;
  border-radius:2px;
  letter-spacing:0.08em;
  white-space:nowrap;
}
.section__title{
  font-family:var(--font-display);
  font-weight:600;
  font-size:1.55rem;
  margin:0;
  letter-spacing:0.01em;
}
.section__note{
  font-family:var(--font-body);
  font-style:italic;
  color:var(--slate);
  font-size:0.92rem;
  margin:0 0 0 auto;
}

.book-grid{
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(250px, 1fr));
  gap:1.8rem;
}

/* ---------- book dossier card ---------- */
.book{
  background:#fff;
  border:1px solid var(--paper-dim);
  border-radius:3px;
  display:flex;
  flex-direction:column;
  overflow:hidden;
  transition:transform 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease;
}
.book:hover{
  transform:translateY(-3px);
  box-shadow:0 14px 30px -14px rgba(11,27,46,0.35);
  border-color:var(--gold);
}

.plate{
  position:relative;
  aspect-ratio:3 / 4;
  background:var(--navy-deep);
  overflow:hidden;
}
.plate img{
  width:100%; height:100%; object-fit:contain;
  display:block;
}
.plate__fallback{
  position:absolute; inset:0;
  display:flex; flex-direction:column; justify-content:space-between;
  padding:0.85rem;
  background:
    radial-gradient(ellipse at 30% 0%, rgba(198,161,91,0.22), transparent 55%),
    linear-gradient(160deg, var(--navy-deep), #16324f);
  color:var(--paper);
}
.plate__fallback-grid{
  position:absolute; inset:0;
  background-image:linear-gradient(var(--navy-line) 1px, transparent 1px), linear-gradient(90deg, var(--navy-line) 1px, transparent 1px);
  background-size:18px 18px;
  opacity:0.4;
}
.plate__fallback-title{
  position:relative;
  font-family:var(--font-display);
  font-weight:600;
  font-size:1.05rem;
  line-height:1.2;
  z-index:1;
}
.plate__fallback-cat{
  position:relative;
  font-family:var(--font-mono);
  font-size:0.62rem;
  letter-spacing:0.1em;
  text-transform:uppercase;
  color:var(--gold-bright);
  z-index:1;
}

/* corner brackets, always over cover art */
.plate__bracket{
  position:absolute; width:16px; height:16px;
  border-color:var(--gold); opacity:0.85; z-index:2;
}
.plate__bracket--tl{ top:8px; left:8px; border-top:2px solid var(--gold); border-left:2px solid var(--gold); }
.plate__bracket--br{ bottom:8px; right:8px; border-bottom:2px solid var(--gold); border-right:2px solid var(--gold); }

.plate__docno{
  position:absolute; top:8px; right:8px; z-index:2;
  font-family:var(--font-mono);
  font-size:0.6rem;
  letter-spacing:0.04em;
  color:var(--gold-bright);
  background:rgba(11,27,46,0.55);
  padding:0.15rem 0.4rem;
  border-radius:1px;
}
.plate__depth{
  position:absolute; bottom:8px; left:8px; z-index:2;
  font-family:var(--font-mono);
  font-size:0.58rem;
  letter-spacing:0.06em;
  text-transform:uppercase;
  color:var(--navy-deep);
  background:var(--gold);
  padding:0.15rem 0.4rem;
  border-radius:1px;
}

/* radar-sweep hover accent, restrained: single pass, only on hover */
.plate::after{
  content:'';
  position:absolute; inset:0;
  background:linear-gradient(100deg, transparent 40%, rgba(230,200,131,0.28) 50%, transparent 60%);
  transform:translateX(-120%);
  transition:transform 0.7s ease;
  pointer-events:none;
}
.book:hover .plate::after{ transform:translateX(120%); }

.book__body{
  padding:1.1rem 1.15rem 1.3rem;
  display:flex;
  flex-direction:column;
  flex:1;
}
.book__title{
  font-family:var(--font-display);
  font-weight:600;
  font-size:1.12rem;
  line-height:1.25;
  margin:0 0 0.2rem;
}
.book__subtitle{
  font-size:0.86rem;
  color:var(--slate);
  font-style:italic;
  margin:0 0 0.6rem;
}
.book__meta{
  font-family:var(--font-mono);
  font-size:0.68rem;
  letter-spacing:0.03em;
  color:var(--slate);
  text-transform:uppercase;
  margin:0 0 0.7rem;
  display:flex; flex-wrap:wrap; gap:0.4rem 0.6rem;
}
.book__meta span::before{ content:'· '; color:var(--gold); }
.book__meta span:first-child::before{ content:''; }

.book__blurb{
  font-size:0.92rem;
  color:var(--ink);
  margin:0 0 1rem;
  flex:1;
}

.book__status{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:0.62rem;
  letter-spacing:0.06em;
  text-transform:uppercase;
  color:var(--gold);
  border:1px solid var(--gold);
  padding:0.1rem 0.45rem;
  border-radius:2px;
  margin-bottom:0.7rem;
  width:fit-content;
}

.book__actions{
  display:flex;
  gap:0.6rem;
  margin-top:auto;
}

/* ---------- buttons ---------- */
.btn{
  font-family:var(--font-mono);
  font-size:0.75rem;
  letter-spacing:0.05em;
  text-transform:uppercase;
  text-decoration:none;
  padding:0.55rem 0.9rem;
  border-radius:2px;
  border:1px solid var(--gold);
  cursor:pointer;
  transition:background 0.15s ease, color 0.15s ease, transform 0.1s ease;
  display:inline-flex;
  align-items:center;
  justify-content:center;
}
.btn:active{ transform:translateY(1px); }
.btn--ghost{
  background:transparent;
  color:var(--navy-deep);
  flex:1;
}
.btn--ghost:hover, .btn--ghost:focus-visible{ background:var(--gold-dim); outline:none; }
.btn--gold{
  background:var(--gold);
  color:var(--navy-deep);
  font-weight:500;
  flex:1;
}
.btn--gold:hover, .btn--gold:focus-visible{ background:var(--gold-bright); outline:none; }
.btn--disabled{
  opacity:0.5;
  cursor:not-allowed;
  pointer-events:none;
}

/* ---------- CTA strip ---------- */
.cta-strip{
  background:var(--navy-mid);
  color:var(--paper);
  border-top:1px solid var(--navy-line);
  border-bottom:1px solid var(--navy-line);
}
.cta-strip__inner{
  max-width:var(--maxw);
  margin:0 auto;
  padding:2.4rem 1.5rem;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:1.5rem;
  flex-wrap:wrap;
}
.cta-strip h2{
  font-family:var(--font-display);
  font-weight:500;
  font-size:1.25rem;
  margin:0;
  max-width:32ch;
}

/* ---------- footer ---------- */
.site-footer{
  background:var(--navy-deep);
  color:var(--slate-light);
}
.site-footer__inner{
  max-width:var(--maxw);
  margin:0 auto;
  padding:2rem 1.5rem 2.4rem;
  font-size:0.8rem;
}
.site-footer__inner p{ margin:0 0 0.6rem; }
.site-footer__links a{ color:var(--gold-bright); text-decoration:none; }
.site-footer__links a:hover{ text-decoration:underline; }

/* ---------- sample reader modal ---------- */
.reader{
  position:fixed; inset:0;
  background:rgba(11,27,46,0.72);
  display:flex;
  align-items:center;
  justify-content:center;
  padding:1.5rem;
  z-index:100;
  opacity:0;
  pointer-events:none;
  transition:opacity 0.18s ease;
}
.reader.is-open{ opacity:1; pointer-events:auto; }
.reader__panel{
  background:var(--paper);
  max-width:640px;
  width:100%;
  max-height:82vh;
  overflow-y:auto;
  padding:2.2rem 2.2rem 2rem;
  border-radius:3px;
  border-top:4px solid var(--gold);
  position:relative;
  box-shadow:0 30px 60px -20px rgba(0,0,0,0.5);
}
.reader__close{
  position:absolute; top:0.9rem; right:0.9rem;
  background:none; border:none;
  font-size:1rem;
  cursor:pointer;
  color:var(--slate);
  width:32px; height:32px;
  border-radius:2px;
}
.reader__close:hover, .reader__close:focus-visible{ background:var(--paper-dim); outline:none; }
.reader__panel h3{
  font-family:var(--font-display);
  font-size:1.5rem;
  margin:0 0 0.3rem;
}
.reader__format{
  font-family:var(--font-mono);
  font-size:0.72rem;
  color:var(--slate);
  text-transform:uppercase;
  letter-spacing:0.05em;
  margin:0 0 1.2rem;
}
.reader__body{
  font-size:0.98rem;
  line-height:1.7;
}
.reader__body p{ margin:0 0 1em; }
.reader__body p:last-child{
  -webkit-mask-image:linear-gradient(180deg, black 60%, transparent 100%);
  mask-image:linear-gradient(180deg, black 60%, transparent 100%);
}
.reader__actions{
  margin-top:1.6rem;
  padding-top:1.2rem;
  border-top:1px solid var(--paper-dim);
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:1rem;
  flex-wrap:wrap;
}
.reader__note{ font-size:0.8rem; color:var(--slate); font-style:italic; }
.reader__note--error{ color:#a33; font-style:normal; }
.reader__note--error:empty{ display:none; }

.checkout-form{
  display:flex;
  flex-direction:column;
  gap:0.35rem;
  margin-top:1rem;
}
.checkout-form label{
  font-family:var(--font-mono);
  font-size:0.68rem;
  letter-spacing:0.05em;
  text-transform:uppercase;
  color:var(--slate);
  margin-top:0.6rem;
}
.checkout-form input{
  font-family:var(--font-body);
  font-size:0.95rem;
  padding:0.55rem 0.7rem;
  border:1px solid var(--paper-dim);
  border-radius:2px;
  background:#fff;
  color:var(--ink);
}
.checkout-form input:focus-visible{
  outline:2px solid var(--gold);
  outline-offset:1px;
  border-color:var(--gold);
}
.checkout-form button{ margin-top:1rem; }

.checkout__success{
  font-size:1rem;
  margin:1rem 0 1.2rem;
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  html{ scroll-behavior:auto; }
  .book, .plate::after, .reader{ transition:none; }
}

/* ---------- responsive ---------- */
@media (max-width: 720px){
  .site-header__inner{ flex-direction:column; align-items:flex-start; gap:0.7rem; }
  .site-nav{ justify-content:flex-start; width:100%; }
  .hero{ padding:3.2rem 1.2rem 2.6rem; }
  #catalogue{ padding:0 1.2rem; }
  .section__note{ margin-left:0; }
  .cta-strip__inner{ flex-direction:column; align-items:flex-start; }
}

/* ---------- how-to-acquire section ---------- */
.howto-section{
  max-width:var(--maxw);
  margin:0 auto;
  padding:3.4rem 1.5rem;
  border-top:1px solid var(--paper-dim);
}

.howto-steps{
  list-style:none;
  margin:0;
  padding:0;
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(200px, 1fr));
  gap:1.6rem;
}

.howto-step{
  position:relative;
  padding:1.3rem 1.2rem 1.2rem;
  background:#fff;
  border:1px solid var(--paper-dim);
  border-radius:3px;
  border-top:2px solid var(--gold);
}

.howto-step__num{
  display:inline-block;
  font-family:var(--font-mono);
  font-size:0.68rem;
  letter-spacing:0.06em;
  color:var(--navy-deep);
  background:var(--gold);
  padding:0.15rem 0.5rem;
  border-radius:1px;
  margin-bottom:0.7rem;
}

.howto-step__title{
  font-family:var(--font-display);
  font-weight:600;
  font-size:1rem;
  margin:0 0 0.4rem;
  color:var(--ink);
}

.howto-step__body{
  font-size:0.88rem;
  color:var(--slate);
  margin:0;
  line-height:1.6;
}
.howto-step__body strong{ color:var(--ink); }

.howto-help{
  margin:2rem 0 0;
  padding:1rem 1.2rem;
  background:var(--gold-dim);
  border-left:3px solid var(--gold);
  border-radius:2px;
  font-size:0.88rem;
  color:var(--ink);
}
.howto-help a{ color:var(--navy-deep); font-weight:600; text-decoration:underline; }

@media (max-width: 720px){
  .howto-section{ padding:2.6rem 1.2rem; }
}