/* ═══════════════════════════════════════
   OPTI-WATT — Feuille de style globale
   ═══════════════════════════════════════ */

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

:root {
  --bg:          #EEF3F8;
  --bg-mid:      #E0E9F2;
  --bg-card:     #F7FAFD;
  --border:      rgba(100,140,180,0.18);
  --border-md:   rgba(100,140,180,0.32);
  --text-primary:   #0E1E2E;
  --text-secondary: #3D5A73;
  --text-muted:     #7A99B2;
  --accent:       #0A7AE0;
  --accent-hover: #0563BE;
  --accent-light: rgba(10,122,224,0.10);
  --accent-border: rgba(10,122,224,0.28);
  --success: #17A471;
  --danger:  #D63B3B;
  --warn:    #D97706;
  --radius:    5px;
  --radius-lg: 14px;
}

html { scroll-behavior: smooth; }
body {
  font-family: 'DM Sans', sans-serif;
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

/* ── NAV ── */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 200;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.9rem 5vw;
  background: rgba(238,243,248,0.95);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.3s;
}
nav.scrolled { box-shadow: 0 4px 24px rgba(10,122,224,0.08); }

.nav-logo {
  font-family: 'Syne', sans-serif; font-weight: 800; font-size: 1.35rem;
  color: var(--accent); letter-spacing: -0.02em; text-decoration: none;
}
.nav-logo span { color: var(--text-primary); }

.nav-links { display: flex; gap: 0.25rem; list-style: none; align-items: center; }
.nav-links a {
  color: var(--text-muted); text-decoration: none; font-size: 0.88rem;
  padding: 0.4rem 0.85rem; border-radius: var(--radius);
  transition: color 0.2s, background 0.2s;
}
.nav-links a:hover, .nav-links a.active {
  color: var(--accent); background: var(--accent-light);
}
.nav-links a.nav-cta {
  background: var(--accent); color: #fff !important; font-weight: 600;
  padding: 0.45rem 1.1rem; margin-left: 0.5rem;
}
.nav-links a.nav-cta:hover { background: var(--accent-hover); }

/* Hamburger */
.nav-burger {
  display: none; flex-direction: column; gap: 5px; cursor: pointer;
  padding: 4px; background: none; border: none;
}
.nav-burger span {
  display: block; width: 24px; height: 2px;
  background: var(--text-primary); border-radius: 2px;
  transition: transform 0.3s, opacity 0.3s;
}
.nav-burger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-burger.open span:nth-child(2) { opacity: 0; }
.nav-burger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── PAGE HEADER ── */
.page-header {
  padding: 8rem 5vw 4rem;
  background: linear-gradient(145deg, #E4EFF9 0%, #EEF3F8 60%);
  position: relative; overflow: hidden;
}
.page-header::before {
  content: ''; position: absolute; top: -100px; right: -100px;
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(10,122,224,0.07) 0%, transparent 70%);
  pointer-events: none;
}
.page-header-label {
  font-size: 0.72rem; font-weight: 500; letter-spacing: 0.13em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 0.75rem;
}
.page-header-title {
  font-family: 'Syne', sans-serif;
  font-size: clamp(2rem, 4vw, 3.5rem);
  font-weight: 800; letter-spacing: -0.03em; line-height: 1.1;
  color: var(--text-primary); margin-bottom: 1rem;
}
.page-header-title em { font-style: normal; color: var(--accent); }
.page-header-desc {
  font-size: 1.05rem; color: var(--text-secondary);
  max-width: 580px; line-height: 1.75; font-weight: 300;
}

/* ── SECTIONS ── */
section { padding: 5rem 5vw; }
.section-label {
  font-size: 0.72rem; font-weight: 500; letter-spacing: 0.13em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 0.85rem;
}
.section-title {
  font-family: 'Syne', sans-serif;
  font-size: clamp(1.7rem, 3vw, 2.5rem);
  font-weight: 700; letter-spacing: -0.025em; line-height: 1.15;
  margin-bottom: 1rem; color: var(--text-primary);
}
.section-desc {
  color: var(--text-secondary); font-size: 1rem;
  max-width: 520px; line-height: 1.75; font-weight: 300;
}
.sep { height: 1px; background: var(--border); margin: 0 5vw; }
.bg-mid { background: var(--bg-mid); }

/* ── BOUTONS ── */
.btn-primary {
  background: var(--accent); color: #fff;
  font-family: 'DM Sans', sans-serif; font-weight: 600; font-size: 0.95rem;
  padding: 0.82rem 2rem; border-radius: var(--radius); border: none;
  cursor: pointer; text-decoration: none;
  transition: background 0.2s, transform 0.15s; display: inline-block;
}
.btn-primary:hover { background: var(--accent-hover); transform: translateY(-1px); }
.btn-secondary {
  color: var(--text-secondary); font-family: 'DM Sans', sans-serif;
  font-weight: 400; font-size: 0.95rem; padding: 0.82rem 1.5rem;
  border-radius: var(--radius); border: 1px solid var(--border-md);
  background: transparent; cursor: pointer; text-decoration: none;
  transition: border-color 0.2s, background 0.2s, color 0.2s; display: inline-block;
}
.btn-secondary:hover { border-color: var(--accent); background: var(--accent-light); color: var(--accent); }

/* ── CARTES ── */
.card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: 1.75rem;
  transition: border-color 0.3s, box-shadow 0.2s, transform 0.2s;
}
.card:hover {
  border-color: var(--accent-border);
  box-shadow: 0 8px 28px rgba(10,122,224,0.08);
  transform: translateY(-2px);
}
.card-icon {
  width: 44px; height: 44px; border-radius: 10px;
  background: var(--accent-light); border: 1px solid var(--accent-border);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 1.1rem; font-size: 1.3rem;
}
.card-title {
  font-family: 'Syne', sans-serif; font-weight: 700; font-size: 1rem;
  margin-bottom: 0.5rem; color: var(--text-primary);
}
.card-desc { font-size: 0.87rem; color: var(--text-muted); line-height: 1.65; }

/* ── GRID UTILITAIRES ── */
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.25rem; }
.grid-3 { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1.25rem; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 1rem; }

/* ── FOOTER ── */
footer {
  background: var(--text-primary); color: rgba(255,255,255,0.7);
  padding: 4rem 5vw 2rem;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 3rem;
  margin-bottom: 3rem; padding-bottom: 3rem;
  border-bottom: 1px solid rgba(255,255,255,0.1);
}
.footer-logo {
  font-family: 'Syne', sans-serif; font-weight: 800; font-size: 1.4rem;
  color: #fff; margin-bottom: 0.75rem; display: block;
}
.footer-tagline { font-size: 0.88rem; line-height: 1.65; margin-bottom: 1.25rem; }
.footer-contact a {
  display: flex; align-items: center; gap: 0.5rem;
  color: rgba(255,255,255,0.7); text-decoration: none; font-size: 0.88rem;
  margin-bottom: 0.5rem; transition: color 0.2s;
}
.footer-contact a:hover { color: #fff; }
.footer-contact svg { width: 15px; height: 15px; stroke: currentColor; fill: none; flex-shrink: 0; }
.footer-col-title {
  font-family: 'Syne', sans-serif; font-weight: 600; font-size: 0.88rem;
  color: #fff; margin-bottom: 1rem; letter-spacing: 0.05em;
  text-transform: uppercase;
}
.footer-col a {
  display: block; color: rgba(255,255,255,0.6); text-decoration: none;
  font-size: 0.87rem; margin-bottom: 0.5rem; transition: color 0.2s;
}
.footer-col a:hover { color: #fff; }
.footer-bottom {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 0.75rem; font-size: 0.8rem;
}
.footer-bottom a { color: rgba(255,255,255,0.5); text-decoration: none; }
.footer-bottom a:hover { color: #fff; }

/* ── ANIMATIONS SCROLL ── */
.reveal {
  opacity: 0; transform: translateY(28px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}
.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ── FORMULAIRE ── */
.form-field { margin-bottom: 1.15rem; }
.form-label {
  display: block; font-size: 0.78rem; color: var(--text-muted);
  text-transform: uppercase; letter-spacing: 0.07em; margin-bottom: 0.4rem;
}
.form-input, .form-select, .form-textarea {
  width: 100%; background: var(--bg); border: 1px solid var(--border-md);
  border-radius: var(--radius); color: var(--text-primary);
  font-family: 'DM Sans', sans-serif; font-size: 0.93rem;
  padding: 0.65rem 0.9rem; outline: none;
  transition: border-color 0.2s, box-shadow 0.2s; appearance: none;
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
  border-color: var(--accent); box-shadow: 0 0 0 3px rgba(10,122,224,0.12);
}
.form-textarea { resize: vertical; min-height: 120px; }
.form-input::placeholder, .form-textarea::placeholder { color: var(--text-muted); }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-error { display: none; color: var(--danger); font-size: 0.76rem; margin-top: 0.28rem; }
.input-error { border-color: var(--danger) !important; background: rgba(214,59,59,0.05) !important; }
.req { color: var(--accent); }

/* ── RESPONSIVE ── */
@media (max-width: 900px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 768px) {
  .nav-links { display: none; flex-direction: column; position: fixed; top: 60px; left: 0; right: 0; background: var(--bg-card); border-bottom: 1px solid var(--border); padding: 1rem 5vw; gap: 0.25rem; }
  .nav-links.open { display: flex; }
  .nav-burger { display: flex; }
  .footer-grid { grid-template-columns: 1fr; gap: 2rem; }
  .form-row { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; }
}