/* ==========================================================================
   Pôle de recherche Chimie Balard — styles du site
   Palette reprise du site existant : #FF7A00, #3B3B3B, #D9D9D9, #FAFAFA
   ========================================================================== */

:root {
  --primary: #FF7A00;
  --primary-dark: #e56a00;
  --ink: #3B3B3B;
  --ink-soft: #5a5a5a;
  --border: #D9D9D9;
  --bg: #FAFAFA;
  --white: #ffffff;
  --radius: 0.875rem;
  --shadow: 0 10px 30px rgba(32, 32, 32, 0.08);
  --font: 'Inter', system-ui, -apple-system, sans-serif;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  color: var(--ink);
  background: var(--bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* ---- Typographie ---- */
h1, h2, h3, h4 {
  color: var(--ink);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

h1 { font-size: clamp(2rem, 5vw, 3.25rem); }
h2 { font-size: clamp(1.5rem, 3vw, 2.25rem); }
h3 { font-size: 1.25rem; }

.section-label {
  display: inline-block;
  font-family: 'Lucida Console', monospace;
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--primary);
  margin-bottom: 0.75rem;
}

.container {
  width: 100%;
  max-width: 1180px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

section { padding: 4.5rem 0; }

a { color: var(--primary-dark); text-decoration: none; }
a:hover { text-decoration: underline; }

/* ---- Header ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 72px;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.15rem;
  font-weight: 700;
  font-size: 1.25rem;
  letter-spacing: -0.02em;
  color: var(--ink);
}

.brand:hover { text-decoration: none; }
.brand .brand-mark { color: var(--primary); }

.brand-sub {
  display: block;
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.site-nav ul {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 0.35rem;
  margin: 0;
  padding: 0;
}

.nav-link {
  display: block;
  padding: 0.5rem 0.75rem;
  border-radius: 0.5rem;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--ink);
}

.nav-link:hover { background: var(--bg); text-decoration: none; }
.nav-link[aria-current="page"] { color: var(--primary); }

.has-dropdown { position: relative; }

.dropdown {
  position: absolute;
  top: calc(100% + 6px);
  left: 0;
  min-width: 260px;
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 0.5rem;
  display: none;
  flex-direction: column;
}

.dropdown a {
  padding: 0.5rem 0.75rem;
  border-radius: 0.5rem;
  font-size: 0.9rem;
  color: var(--ink);
}

.dropdown a:hover { background: var(--bg); text-decoration: none; }
.dropdown a[aria-current="page"] { color: var(--primary); }

.has-dropdown.is-open .dropdown,
.has-dropdown:focus-within .dropdown { display: flex; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.5rem 0.65rem;
  cursor: pointer;
  color: var(--ink);
}

.nav-toggle .icon-burger { display: block; }
.nav-toggle .icon-close { display: none; }
.nav-toggle[aria-expanded="true"] .icon-burger { display: none; }
.nav-toggle[aria-expanded="true"] .icon-close { display: block; }

/* ---- Boutons ---- */
.btn {
  display: inline-block;
  padding: 0.8rem 1.6rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  background: var(--primary);
  color: var(--white);
  transition: background 0.2s ease, transform 0.2s ease;
}

.btn:hover { background: var(--primary-dark); text-decoration: none; transform: translateY(-2px); }

.btn-outline {
  background: transparent;
  color: var(--ink);
  border: 1.5px solid var(--border);
}

.btn-outline:hover { border-color: var(--primary); color: var(--primary); background: transparent; }

/* ---- Hero ---- */
.hero {
  position: relative;
  min-height: 78vh;
  display: flex;
  align-items: center;
  color: #fff;
  overflow: hidden;
  background: rgba(32, 32, 32, 0.75);
}

.hero video,
.hero img.hero-media {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  z-index: -1;
}

.hero .hero-inner { max-width: 820px; }

.hero h1 { color: #fff; }
.hero .hero-sub { font-size: 1.25rem; color: rgba(255,255,255,0.92); }
.hero .hero-tag { color: var(--primary); font-weight: 600; text-transform: uppercase; letter-spacing: 0.12em; font-size: 0.85rem; }
.hero .hero-actions { margin-top: 2rem; display: flex; gap: 1rem; flex-wrap: wrap; }

/* ---- Cartes ---- */
.card {
  background: var(--white);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
  display: flex;
  flex-direction: column;
}

.card:hover { transform: translateY(-6px); box-shadow: var(--shadow); }

.card img { width: 100%; height: 200px; object-fit: cover; display: block; }

.card-body { padding: 1.5rem; display: flex; flex-direction: column; gap: 0.75rem; flex: 1; }

.card-body h3 { font-size: 1.1rem; }
.card-body p { margin: 0; color: var(--ink-soft); font-size: 0.95rem; }

.card .btn { align-self: flex-start; margin-top: auto; }

.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }

/* ---- Sections ---- */
.section-white { background: var(--white); }
.section-head { max-width: 720px; margin-bottom: 2.5rem; }
.section-head p { color: var(--ink-soft); }

/* ---- Chiffres clés ---- */
.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }
.stat { text-align: center; padding: 2rem 1rem; background: var(--white); border: 1px solid var(--border); border-radius: var(--radius); }
.stat .stat-value { font-size: 2.5rem; font-weight: 700; color: var(--primary); }
.stat .stat-label { color: var(--ink-soft); font-size: 0.9rem; }

/* ---- Éditorial ---- */
.prose { max-width: 780px; color: var(--ink-soft); }
.prose h2 { color: var(--ink); margin: 2.5rem 0 1rem; }
.prose p { margin: 0 0 1.1rem; }
.prose ul { margin: 0 0 1.1rem; padding-left: 1.25rem; }
.prose li { margin-bottom: 0.4rem; }

.img-frame { border-radius: var(--radius); overflow: hidden; }
.img-frame img { width: 100%; height: auto; display: block; }

/* ---- Formulaire ---- */
.form-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
.field { display: flex; flex-direction: column; gap: 0.4rem; }
.field.full { grid-column: 1 / -1; }
.field label { font-weight: 600; font-size: 0.9rem; }
.field input,
.field select,
.field textarea {
  padding: 0.8rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.6rem;
  font: inherit;
  color: var(--ink);
  background: var(--white);
}
.field input:focus,
.field select:focus,
.field textarea:focus {
  outline: 2px solid var(--primary);
  outline-offset: 1px;
  border-color: var(--primary);
}

/* ---- Coordonnées ---- */
.contact-info { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.contact-block { background: var(--white); border: 1px solid var(--border); border-radius: var(--radius); padding: 1.75rem; }
.contact-block h3 { margin-top: 0; }

/* ---- Footer ---- */
.site-footer {
  background: var(--ink);
  color: rgba(255, 255, 255, 0.85);
  padding: 3.5rem 0 0;
  margin-top: 2rem;
}

.site-footer a { color: rgba(255, 255, 255, 0.85); }
.site-footer a:hover { color: #fff; }

.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 2.5rem;
  padding-bottom: 2.5rem;
}

.site-footer h4 { color: #fff; margin: 0 0 1rem; font-size: 1rem; }
.site-footer ul { list-style: none; margin: 0; padding: 0; }
.site-footer li { margin-bottom: 0.5rem; font-size: 0.92rem; }

.footer-bottom {
  border-top: 1px solid rgba(255, 255, 255, 0.15);
  padding: 1.25rem 0;
  font-size: 0.85rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ---- Apparition au scroll ---- */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.is-visible { opacity: 1; transform: none; }

/* ---- Divers ---- */
.pill {
  display: inline-block;
  padding: 0.25rem 0.8rem;
  border-radius: 999px;
  background: rgba(255, 122, 0, 0.12);
  color: var(--primary-dark);
  font-size: 0.8rem;
  font-weight: 600;
}

.article-card time { color: var(--ink-soft); font-size: 0.85rem; }

/* ---- Responsive ---- */
@media (max-width: 1024px) {
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .stats { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 860px) {
  .nav-toggle { display: block; }

  .site-nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--white);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    display: none;
    padding: 1rem 1.5rem 1.5rem;
  }

  .site-nav.is-open { display: block; }
  .site-nav ul { flex-direction: column; align-items: stretch; gap: 0.25rem; }
  .nav-link { padding: 0.7rem 0.75rem; }
  .has-dropdown .dropdown { position: static; box-shadow: none; border: none; padding: 0 0 0 1rem; display: none; }
  .has-dropdown.is-open .dropdown { display: flex; }

  .grid-3, .grid-2, .contact-info { grid-template-columns: 1fr; }
  .form-grid { grid-template-columns: 1fr; }
  .footer-grid { grid-template-columns: 1fr; }
}

@media (max-width: 560px) {
  .grid-4, .stats { grid-template-columns: 1fr; }
  .hero { min-height: 62vh; }
}