:root {
  --abyss: #020d20;
  --deep: #061a36;
  --accent: #53bcff;
  --ice: #e8f4ff;
  --mist: #9fb4cc;
  --serif: "Montserrat", system-ui, sans-serif;
  --sans: "Inter", system-ui, sans-serif;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--abyss);
  color: var(--ice);
  font: 300 18px/1.7 var(--sans);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}
img { display: block; max-width: 100%; }
a { color: inherit; }
h1, h2, h3 { font-family: var(--serif); font-weight: 500; line-height: 1.15; }
.kicker {
  font: 500 13px/1 var(--serif);
  letter-spacing: .35em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
}

/* Navigation */
.nav {
  position: fixed; inset: 0 0 auto 0; z-index: 10;
  display: flex; justify-content: space-between; align-items: center;
  padding: 18px clamp(16px, 4vw, 48px);
  transition: background .4s, backdrop-filter .4s;
}
.nav.scrolled { background: rgba(2, 13, 32, .78); backdrop-filter: blur(12px); }
.nav-brand {
  display: flex; align-items: center; gap: 10px; text-decoration: none;
  font: 500 15px var(--serif); letter-spacing: .12em; text-transform: uppercase;
  opacity: 0; transition: opacity .4s;
}
.nav.scrolled .nav-brand { opacity: 1; }
.nav nav { display: flex; align-items: center; gap: clamp(14px, 3vw, 36px); }
.nav nav a {
  text-decoration: none; font: 400 14px var(--serif); letter-spacing: .08em;
  color: var(--mist); transition: color .2s;
}
.nav nav a:hover { color: var(--accent); }

/* Hero */
.hero {
  position: relative; min-height: 100vh; min-height: 100svh;
  display: grid; place-items: center; text-align: center;
  background: radial-gradient(ellipse at 50% 30%, #0b2a52 0%, var(--abyss) 70%);
  overflow: hidden;
  padding: 96px 0 16vh;
}
#sea { position: absolute; inset: 0; width: 100%; height: 100%; }
.hero-inner { position: relative; padding: 0 16px; animation: rise 1.6s ease-out both; }
.hero-logo { width: min(560px, 86vw, 66vh); height: auto; margin: 0 auto 28px; filter: drop-shadow(0 0 40px rgba(83, 188, 255, .25)); }
.hero h1 { font-size: clamp(36px, 6vw, 76px); font-weight: 300; letter-spacing: -.01em; }
.lead { margin: 18px auto 0; max-width: 640px; color: var(--mist); font-size: clamp(16px, 2vw, 20px); }
.scroll {
  display: block; width: 26px; height: 44px; margin: 56px auto 0;
  border: 1.5px solid rgba(232, 244, 255, .5); border-radius: 14px; position: relative;
}
.scroll span {
  position: absolute; left: 50%; top: 8px; width: 3px; height: 8px; margin-left: -1.5px;
  background: var(--accent); border-radius: 2px; animation: drip 2s infinite;
}
@keyframes drip { 0% { opacity: 0; transform: translateY(0); } 30% { opacity: 1; } 100% { opacity: 0; transform: translateY(16px); } }
@keyframes rise { from { opacity: 0; transform: translateY(24px); } to { opacity: 1; transform: none; } }

/* Le problème : foncier, électricité, eau */
.problem {
  max-width: 1280px; margin: 0 auto; text-align: center;
  padding: clamp(80px, 12vw, 160px) clamp(16px, 4vw, 48px) 0;
}
.problem-head h2 { font-size: clamp(30px, 4.4vw, 56px); font-weight: 300; margin-bottom: 18px; }
.problem-head p:not(.kicker) { color: var(--mist); max-width: 560px; margin: 0 auto; }
.constraints { display: grid; grid-template-columns: repeat(3, 1fr); gap: clamp(16px, 3vw, 32px); margin-top: 64px; text-align: left; }
.constraint {
  padding: 36px 32px; border-radius: 6px;
  background: linear-gradient(160deg, rgba(83, 188, 255, .08), rgba(83, 188, 255, .02));
  border: 1px solid rgba(83, 188, 255, .16);
}
.constraint svg { width: 44px; height: 44px; fill: none; stroke: var(--accent); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; margin-bottom: 22px; }
.constraint h3 { font-size: 22px; letter-spacing: .04em; margin-bottom: 12px; }
.constraint p { color: var(--mist); font-size: 16px; }
.constraint.reveal:nth-child(2) { transition-delay: .15s; }
.constraint.reveal:nth-child(3) { transition-delay: .3s; }
.problem-turn { margin-top: 64px; font: 300 clamp(20px, 2.4vw, 28px)/1.4 var(--serif); color: var(--ice); }

/* Split */
.split {
  display: grid; grid-template-columns: 1.1fr 1fr; gap: clamp(32px, 6vw, 96px);
  align-items: center; max-width: 1280px; margin: 0 auto;
  padding: clamp(80px, 12vw, 160px) clamp(16px, 4vw, 48px);
}
.split-img { border-radius: 4px; overflow: hidden; aspect-ratio: 4 / 5; }
.split-img img { width: 100%; height: 100%; object-fit: cover; transform: scale(1.04); transition: transform 8s ease-out; }
.split-img.visible img { transform: scale(1); }
.split h2, .vision h2 { font-size: clamp(28px, 3.6vw, 46px); margin-bottom: 28px; }
.split p:not(.kicker), .vision p:not(.kicker) { color: var(--mist); margin-bottom: 16px; max-width: 520px; }
.split p:last-child { color: var(--ice); font-weight: 500; }

/* Piliers */
.pillars {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: clamp(20px, 3vw, 40px);
  max-width: 1280px; margin: 0 auto; padding: 0 clamp(16px, 4vw, 48px) clamp(80px, 12vw, 160px);
}
.pillar-img { aspect-ratio: 3 / 4; overflow: hidden; border-radius: 4px; margin-bottom: 24px; }
.pillar-img img { width: 100%; height: 100%; object-fit: cover; transition: transform 1.2s ease; }
.pillar:hover .pillar-img img { transform: scale(1.06); }
.pillar h3 { font-size: 22px; letter-spacing: .04em; margin-bottom: 10px; }
.pillar h3::before { content: ""; display: block; width: 28px; height: 2px; background: var(--accent); margin-bottom: 16px; }
.pillar p { color: var(--mist); font-size: 16px; }

/* Bandeau citation */
.band {
  position: relative; min-height: 80vh; display: grid; place-items: center; text-align: center;
  background: linear-gradient(rgba(2, 13, 32, .68), rgba(2, 13, 32, .85)), var(--img) center / cover fixed;
  padding: 80px 16px;
}
.band blockquote { font: 300 clamp(26px, 4vw, 52px)/1.3 var(--serif); max-width: 980px; }
.band cite { display: block; margin-top: 28px; font: 400 clamp(15px, 1.6vw, 19px) var(--sans); font-style: normal; color: var(--accent); letter-spacing: .06em; }

/* Vision */
.vision {
  display: grid; grid-template-columns: 1fr 1.2fr; gap: clamp(32px, 6vw, 96px); align-items: center;
  max-width: 1280px; margin: 0 auto; padding: clamp(80px, 12vw, 160px) clamp(16px, 4vw, 48px);
}
.mosaic { display: grid; grid-template-columns: 1fr 1fr; grid-template-rows: 220px 220px; gap: 14px; }
.mosaic figure { overflow: hidden; border-radius: 4px; }
.mosaic img { width: 100%; height: 100%; object-fit: cover; }
.m1 { grid-row: span 2; }

/* Contact */
.contact {
  text-align: center; padding: clamp(100px, 14vw, 180px) 16px;
  background: linear-gradient(var(--abyss), var(--deep));
}
.contact-icon { margin: 0 auto 32px; filter: drop-shadow(0 0 30px rgba(83, 188, 255, .35)); }
.contact h2 { font-size: clamp(30px, 4.4vw, 56px); font-weight: 300; margin-bottom: 18px; }
.contact p { color: var(--mist); max-width: 560px; margin: 0 auto; }

footer {
  background: var(--deep); border-top: 1px solid rgba(83, 188, 255, .12);
  text-align: center; padding: 32px 16px; font-size: 13px; color: var(--mist);
}
.credits { opacity: .6; margin-top: 6px; font-size: 12px; }

/* Apparition au défilement */
.reveal { opacity: 0; transform: translateY(32px); transition: opacity 1s ease, transform 1s ease; }
.reveal.visible { opacity: 1; transform: none; }
.pillar.reveal:nth-child(2) { transition-delay: .15s; }
.pillar.reveal:nth-child(3) { transition-delay: .3s; }

@media (max-width: 860px) {
  .constraints { grid-template-columns: 1fr; }
  .split, .vision { grid-template-columns: 1fr; }
  .split-img { aspect-ratio: 4 / 3; }
  .pillars { grid-template-columns: 1fr; }
  .pillar-img { aspect-ratio: 16 / 10; }
  .mosaic { grid-template-rows: 160px 160px; }
  .band { background-attachment: scroll; }
  .nav nav a:not(:last-child) { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; }
  .reveal { opacity: 1; transform: none; }
}

/* Appel à l'action et formulaire « Request the deck » */
.accent { color: var(--accent); }
.btn {
  display: inline-block; margin-top: 36px; padding: 15px 34px;
  font: 500 15px var(--serif); letter-spacing: .1em; text-transform: uppercase; text-decoration: none;
  color: var(--abyss); background: var(--accent); border: 0; border-radius: 40px; cursor: pointer;
  box-shadow: 0 0 40px rgba(83, 188, 255, .35); transition: transform .2s, box-shadow .2s, background .2s;
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 0 60px rgba(83, 188, 255, .55); background: #7dcdff; }
.btn:disabled { opacity: .6; cursor: wait; transform: none; }
.hero .scroll { margin-top: 40px; }
.nav nav a.nav-cta {
  color: var(--accent); border: 1px solid rgba(83, 188, 255, .6); border-radius: 30px; padding: 7px 16px; white-space: nowrap;
}
.nav nav a.nav-cta:hover { background: var(--accent); color: var(--abyss); }

.deck-form {
  display: flex; gap: 10px; max-width: 560px; margin: 44px auto 0; padding: 6px;
  background: rgba(232, 244, 255, .06); border: 1px solid rgba(159, 180, 204, .3); border-radius: 40px;
  transition: border-color .2s;
}
.deck-form:focus-within { border-color: var(--accent); }
.deck-form input[type=email] {
  flex: 1; min-width: 0; padding: 0 20px; font: 400 16px var(--sans); color: var(--ice);
  background: transparent; border: 0; outline: none;
}
.deck-form input::placeholder { color: var(--mist); opacity: .7; }
.deck-form .btn { margin: 0; padding: 14px 26px; white-space: nowrap; }
.deck-form .hp { position: absolute; left: -9999px; width: 1px; height: 1px; opacity: 0; }
.form-status { text-align: center; min-height: 1.7em; margin-top: 18px; color: var(--mist); }
.form-status.ok { color: var(--accent); font-size: 20px; }
.form-status.err { color: #ff9b8a; }
@media (max-width: 860px) {
  .nav nav a.nav-cta { display: inline-block; }
}
@media (max-width: 480px) {
  .deck-form { flex-direction: column; border-radius: 18px; padding: 8px; }
  .deck-form input[type=email] { padding: 12px 14px; }
}