/* ===================================================
   ZEPPELIN — Fiche Universitaire · Transport Aérien
   Style Art Déco / Âge d'or des dirigeables (1900–1940)
   =================================================== */

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,400;0,700;0,900;1,400&family=Cormorant+Garamond:ital,wght@0,300;0,400;0,600;1,300;1,400&family=Josefin+Sans:wght@300;400;600&display=swap');

:root {
  --ink:        #1a1209;
  --parchment:  #f5edda;
  --cream:      #fdf8ef;
  --gold:       #b8912a;
  --gold-lt:    #d4aa45;
  --gold-pale:  #f0dfa0;
  --navy:       #0d1f3c;
  --rust:       #7a3520;
  --rule:       #c4a84a;
  --shadow:     rgba(26,18,9,0.18);
}

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background-color: #2b2015;
  background-image:
    repeating-linear-gradient(0deg,   transparent, transparent 39px, rgba(180,140,50,.06) 39px, rgba(180,140,50,.06) 40px),
    repeating-linear-gradient(90deg,  transparent, transparent 39px, rgba(180,140,50,.04) 39px, rgba(180,140,50,.04) 40px);
  font-family: 'Cormorant Garamond', Georgia, serif;
  color: var(--ink);
  min-height: 100vh;
}

/* ── Top Banner ── */
.top-banner {
  background: var(--navy);
  padding: 10px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  border-bottom: 2px solid var(--gold);
}

.top-banner .breadcrumb {
  font-family: 'Josefin Sans', sans-serif;
  font-size: .72rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--gold-lt);
}

.top-banner .breadcrumb span { color: rgba(212,170,69,.45); margin: 0 6px; }

.top-banner .stamp {
  font-family: 'Josefin Sans', sans-serif;
  font-size: .65rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: rgba(212,170,69,.55);
}

/* ── Hero ── */
.hero {
  position: relative;
  overflow: hidden;
  background: var(--navy);
  min-height: 420px;
  display: flex;
  align-items: flex-end;
  padding: 0 0 0 0;
}

.hero-sky {
  position: absolute;
  inset: 0;
  background: linear-gradient(175deg, #060e1e 0%, #0d2245 40%, #1a3a6e 70%, #2e5492 100%);
}

/* Cloud layers */
.hero-sky::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 500px 80px at 20% 65%, rgba(255,255,255,.07) 0%, transparent 70%),
    radial-gradient(ellipse 320px 55px at 65% 72%, rgba(255,255,255,.06) 0%, transparent 70%),
    radial-gradient(ellipse 180px 35px at 85% 60%, rgba(255,255,255,.05) 0%, transparent 70%);
}

/* Gold horizon glow */
.hero-sky::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 120px;
  background: linear-gradient(to top, rgba(184,145,42,.35) 0%, transparent 100%);
}

/* The Zeppelin silhouette — pure CSS */
.zeppelin-svg {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -55%);
  width: min(760px, 88vw);
  opacity: .92;
  animation: drift 18s ease-in-out infinite;
  filter: drop-shadow(0 18px 40px rgba(0,0,0,.55));
}

@keyframes drift {
  0%,100% { transform: translate(-50%,-55%) translateY(0px) rotate(-.4deg); }
  50%      { transform: translate(-50%,-55%) translateY(-14px) rotate(.4deg); }
}

/* Gold decorative rule inside hero */
.hero-rule {
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(to right, transparent, var(--gold), var(--gold-lt), var(--gold), transparent);
}

/* Hero text block */
.hero-text {
  position: relative;
  z-index: 2;
  width: 100%;
  padding: 48px 48px 44px;
  background: linear-gradient(to top, rgba(6,14,30,.92) 0%, rgba(6,14,30,.5) 70%, transparent 100%);
}

.hero-eyebrow {
  font-family: 'Josefin Sans', sans-serif;
  font-size: .7rem;
  letter-spacing: .3em;
  text-transform: uppercase;
  color: var(--gold-lt);
  margin-bottom: 10px;
}

.hero-eyebrow::before, .hero-eyebrow::after {
  content: '——';
  margin: 0 10px;
  opacity: .5;
}

.hero h1 {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: clamp(3.2rem, 7vw, 6rem);
  font-weight: 900;
  color: #fff;
  letter-spacing: .02em;
  line-height: 1.0;
  text-shadow: 0 4px 24px rgba(0,0,0,.7);
}

.hero h1 em {
  display: block;
  font-style: italic;
  font-weight: 400;
  font-size: .48em;
  color: var(--gold-lt);
  letter-spacing: .1em;
  margin-bottom: 4px;
}

.hero-tagline {
  margin-top: 14px;
  font-family: 'Cormorant Garamond', serif;
  font-style: italic;
  font-size: 1.15rem;
  color: rgba(255,255,255,.65);
  max-width: 560px;
}

/* ── Main layout ── */
.main-wrap {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 20px 80px;
}

/* ── Intro strip ── */
.intro-strip {
  background: var(--parchment);
  border-left: 6px solid var(--gold);
  border-right: 6px solid var(--gold);
  padding: 36px 48px;
  margin-bottom: 0;
  text-align: center;
  position: relative;
}

.intro-strip::before, .intro-strip::after {
  content: '';
  display: block;
  height: 1px;
  background: linear-gradient(to right, transparent, var(--rule), transparent);
  margin: 0 0 20px;
}

.intro-strip::after { margin: 20px 0 0; }

.intro-strip p {
  font-size: 1.22rem;
  font-style: italic;
  color: #3a2b14;
  line-height: 1.75;
  max-width: 760px;
  margin: 0 auto;
}

.ornament {
  display: block;
  text-align: center;
  font-size: 1.4rem;
  color: var(--gold);
  margin: 8px 0;
  letter-spacing: .3em;
}

/* ── Content grid ── */
.content-grid {
  display: grid;
  grid-template-columns: 1fr 340px;
  gap: 0;
  background: var(--parchment);
  border-left: 6px solid var(--gold);
  border-right: 6px solid var(--gold);
  border-bottom: 6px solid var(--gold);
}

.main-col {
  padding: 44px 44px 44px 48px;
  border-right: 1px solid rgba(184,145,42,.25);
}

.sidebar {
  padding: 44px 32px 44px;
  background: rgba(240,223,160,.18);
}

/* ── Section headings ── */
.section-heading {
  font-family: 'Playfair Display', Georgia, serif;
  font-size: 1.65rem;
  font-weight: 700;
  color: var(--navy);
  margin: 40px 0 16px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--gold);
  display: flex;
  align-items: center;
  gap: 12px;
}

.section-heading:first-child { margin-top: 0; }

.section-heading .icon {
  font-size: 1.1em;
  flex-shrink: 0;
}

/* ── Body text ── */
.main-col p {
  font-size: 1.1rem;
  line-height: 1.85;
  color: #2a1f0e;
  margin-bottom: 18px;
}

/* ── Spec table ── */
.spec-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-family: 'Josefin Sans', sans-serif;
  font-size: .82rem;
}

.spec-table caption {
  font-family: 'Playfair Display', serif;
  font-size: 1rem;
  font-weight: 700;
  color: var(--navy);
  text-align: left;
  padding-bottom: 8px;
  letter-spacing: .05em;
}

.spec-table th {
  background: var(--navy);
  color: var(--gold-lt);
  padding: 9px 14px;
  text-align: left;
  letter-spacing: .1em;
  text-transform: uppercase;
  font-size: .72rem;
}

.spec-table td {
  padding: 8px 14px;
  border-bottom: 1px solid rgba(184,145,42,.2);
  color: #2a1f0e;
}

.spec-table tr:nth-child(even) td { background: rgba(240,223,160,.25); }

.spec-table td:first-child {
  font-weight: 600;
  color: var(--navy);
  width: 45%;
}

/* ── Timeline ── */
.timeline {
  position: relative;
  padding-left: 28px;
  margin: 16px 0 24px;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px;
  top: 6px;
  bottom: 6px;
  width: 2px;
  background: linear-gradient(to bottom, var(--gold), var(--gold-lt) 50%, transparent);
}

.timeline-item {
  position: relative;
  margin-bottom: 22px;
  opacity: 0;
  transform: translateX(-12px);
  transition: opacity .5s ease, transform .5s ease;
}

.timeline-item.visible {
  opacity: 1;
  transform: translateX(0);
}

.timeline-item::before {
  content: '';
  position: absolute;
  left: -24px;
  top: 6px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--gold);
  border: 2px solid var(--parchment);
  box-shadow: 0 0 0 2px var(--gold);
}

.timeline-year {
  font-family: 'Josefin Sans', sans-serif;
  font-size: .72rem;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--gold);
  font-weight: 600;
  margin-bottom: 2px;
}

.timeline-item p {
  font-size: 1rem !important;
  line-height: 1.6 !important;
  margin: 0 !important;
  color: #2a1f0e;
}

/* ── Disaster box ── */
.disaster-box {
  border: 2px solid var(--rust);
  background: rgba(122,53,32,.06);
  border-radius: 4px;
  padding: 20px 24px;
  margin: 24px 0;
}

.disaster-box .disaster-title {
  font-family: 'Playfair Display', serif;
  font-weight: 700;
  color: var(--rust);
  font-size: 1.05rem;
  margin-bottom: 8px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.disaster-box p {
  font-size: 1rem !important;
  margin: 0 !important;
}

/* ── Sidebar widgets ── */
.sidebar-card {
  background: var(--cream);
  border: 1px solid rgba(184,145,42,.35);
  border-radius: 4px;
  padding: 22px 20px;
  margin-bottom: 24px;
  position: relative;
  overflow: hidden;
}

.sidebar-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: linear-gradient(to right, var(--gold), var(--gold-lt));
}

.sidebar-card h3 {
  font-family: 'Playfair Display', serif;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid rgba(184,145,42,.3);
}

/* Key figure display */
.key-figure {
  text-align: center;
  padding: 10px 0;
  border-bottom: 1px solid rgba(184,145,42,.2);
  margin-bottom: 10px;
}

.key-figure:last-child { border-bottom: none; margin-bottom: 0; }

.key-figure .number {
  display: block;
  font-family: 'Playfair Display', serif;
  font-size: 2.4rem;
  font-weight: 900;
  color: var(--gold);
  line-height: 1;
}

.key-figure .label {
  display: block;
  font-family: 'Josefin Sans', sans-serif;
  font-size: .68rem;
  letter-spacing: .15em;
  text-transform: uppercase;
  color: #5a4a30;
  margin-top: 2px;
}

/* Notable Zeppelins list */
.zeppelin-list { list-style: none; }

.zeppelin-list li {
  display: flex;
  flex-direction: column;
  padding: 10px 0;
  border-bottom: 1px solid rgba(184,145,42,.2);
  cursor: pointer;
  transition: background .2s;
  border-radius: 3px;
  padding: 8px 6px;
}

.zeppelin-list li:hover { background: rgba(184,145,42,.08); }
.zeppelin-list li:last-child { border-bottom: none; }

.zeppelin-list .lz-name {
  font-family: 'Josefin Sans', sans-serif;
  font-weight: 600;
  font-size: .85rem;
  color: var(--navy);
  letter-spacing: .05em;
}

.zeppelin-list .lz-desc {
  font-size: .88rem;
  color: #5a4a30;
  font-style: italic;
  margin-top: 2px;
}

/* Tooltip popup */
.zeppelin-list li .lz-detail {
  display: none;
  font-size: .82rem;
  color: #3a2b14;
  margin-top: 6px;
  padding: 6px 8px;
  background: rgba(240,223,160,.4);
  border-left: 3px solid var(--gold);
  line-height: 1.5;
}

.zeppelin-list li.open .lz-detail { display: block; }

/* Gas comparison */
.gas-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin-top: 8px;
}

.gas-box {
  text-align: center;
  padding: 10px 6px;
  border: 1px solid rgba(184,145,42,.25);
  border-radius: 4px;
}

.gas-box .gas-name {
  font-family: 'Josefin Sans', sans-serif;
  font-size: .75rem;
  letter-spacing: .12em;
  text-transform: uppercase;
  font-weight: 600;
}

.gas-box.h2 { border-color: rgba(200,80,60,.4); background: rgba(200,80,60,.05); }
.gas-box.h2 .gas-name { color: #a03020; }
.gas-box.he  { border-color: rgba(50,110,190,.4); background: rgba(50,110,190,.05); }
.gas-box.he  .gas-name { color: #1a4a8a; }

.gas-box .gas-lift {
  display: block;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--ink);
  margin: 4px 0 2px;
}

.gas-box .gas-note {
  font-size: .76rem;
  color: #6a5a40;
  font-style: italic;
}

/* ── Modernity section ── */
.modern-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin: 20px 0;
}

.modern-card {
  background: var(--cream);
  border: 1px solid rgba(184,145,42,.3);
  border-radius: 4px;
  padding: 18px 16px;
  transition: transform .25s, box-shadow .25s;
  cursor: default;
}

.modern-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(26,18,9,.12);
}

.modern-card .card-icon {
  font-size: 1.8rem;
  margin-bottom: 8px;
}

.modern-card h4 {
  font-family: 'Playfair Display', serif;
  font-size: .98rem;
  font-weight: 700;
  color: var(--navy);
  margin-bottom: 6px;
}

.modern-card p {
  font-size: .92rem !important;
  line-height: 1.6 !important;
  margin: 0 !important;
  color: #3a2b14;
}

/* ── Footer ── */
footer {
  background: var(--navy);
  border-top: 3px solid var(--gold);
  padding: 28px 48px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

footer .footer-brand {
  font-family: 'Playfair Display', serif;
  font-size: 1.05rem;
  font-weight: 700;
  color: var(--gold-lt);
}

footer .footer-meta {
  font-family: 'Josefin Sans', sans-serif;
  font-size: .68rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: rgba(212,170,69,.5);
  text-align: right;
}

/* ── Progress bar (reading indicator) ── */
#read-progress {
  position: fixed;
  top: 0; left: 0;
  height: 3px;
  background: linear-gradient(to right, var(--gold), var(--gold-lt));
  z-index: 1000;
  transition: width .1s linear;
  width: 0%;
}

/* ── Scroll-to-top ── */
#back-top {
  position: fixed;
  bottom: 32px;
  right: 32px;
  width: 44px;
  height: 44px;
  background: var(--navy);
  border: 2px solid var(--gold);
  color: var(--gold-lt);
  font-size: 1.2rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s, transform .3s;
  z-index: 999;
  text-decoration: none;
}

#back-top.visible {
  opacity: 1;
  pointer-events: auto;
}

#back-top:hover { transform: translateY(-3px); }

/* ── Decorative Art-Deco divider ── */
.deco-divider {
  text-align: center;
  margin: 32px 0 8px;
  color: var(--gold);
  font-size: .85rem;
  letter-spacing: .5em;
  user-select: none;
}

/* ── Responsive ── */
@media (max-width: 820px) {
  .content-grid { grid-template-columns: 1fr; }
  .main-col { border-right: none; border-bottom: 1px solid rgba(184,145,42,.2); }
  .modern-grid { grid-template-columns: 1fr; }
  .hero-text { padding: 32px 24px 28px; }
  .intro-strip { padding: 28px 24px; }
  footer { padding: 24px; flex-direction: column; text-align: center; }
  footer .footer-meta { text-align: center; }
}