/* ═══════════════════════════════════════════════════════════════════
   GravitationOS — main.css
   Styles partagés : variables, reset, nav, footer, composants globaux
   ═══════════════════════════════════════════════════════════════════ */

/* ─── Variables ──────────────────────────────────────────────────── */
:root {
  --bg:        #070c18;
  --bg2:       #0d1525;
  --bg3:       #111827;
  --card:      #131e30;
  --border:    rgba(59, 130, 246, .18);
  --blue:      #3b82f6;
  --indigo:    #6366f1;
  --teal:      #14b8a6;
  --text:      #e2e8f0;
  --muted:     #94a3b8;
  --dim:       #64748b;
  --grad1:     linear-gradient(135deg, #3b82f6, #6366f1);
  --grad2:     linear-gradient(135deg, #6366f1, #14b8a6);
  --radius:    14px;
  --t:         .25s ease;
  --nav-h:     64px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  overflow-x: hidden;
  min-height: 100vh;
}

a {
  color: inherit;
  text-decoration: none;
}

img {
  display: block;
  max-width: 100%;
}

button, input, select, textarea {
  font: inherit;
}

ul {
  list-style: none;
}

/* ─── Scrollbar ──────────────────────────────────────────────────── */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

/* ─── Canvas étoiles ─────────────────────────────────────────────── */
#stars-canvas {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: .6;
}

/* ─── Navigation ─────────────────────────────────────────────────── */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  height: var(--nav-h);
  padding: 0 2rem;
  background: rgba(7, 12, 24, .85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* Logo */
.nav-logo {
  display: flex;
  align-items: center;
  gap: .6rem;
  font-weight: 700;
  font-size: 1.15rem;
  letter-spacing: -.02em;
}

.nav-logo svg { width: 32px; height: 32px; }

.nav-logo span {
  background: var(--grad1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* Liens */
.nav-links {
  display: flex;
  align-items: center;
  gap: .15rem;
}

.nav-links li a {
  display: block;
  padding: .45rem .85rem;
  border-radius: 8px;
  font-size: .88rem;
  color: var(--muted);
  transition: color var(--t), background var(--t);
}

.nav-links li a:hover,
.nav-links li a.active {
  color: var(--text);
  background: rgba(59, 130, 246, .12);
}

/* CTA nav */
.nav-cta {
  background: var(--grad1) !important;
  color: #fff !important;
  border-radius: 8px;
  padding: .45rem 1.1rem !important;
  font-weight: 600;
  font-size: .88rem !important;
  transition: opacity var(--t) !important;
}

.nav-cta:hover {
  opacity: .85;
}

/* Bouton hamburger mobile */
.nav-mobile-btn {
  display: none;
  background: none;
  border: none;
  color: var(--muted);
  cursor: pointer;
  padding: .4rem;
}

/* ─── Menu mobile ────────────────────────────────────────────────── */
.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 99;
  background: rgba(7, 12, 24, .97);
  padding: 5rem 2rem 2rem;
  flex-direction: column;
  gap: .5rem;
  overflow-y: auto;
}

.mobile-nav.open {
  display: flex;
}

.mobile-nav a {
  display: block;
  padding: .85rem 1.25rem;
  border-radius: 10px;
  font-size: 1.05rem;
  color: var(--muted);
  border: 1px solid transparent;
  transition: all var(--t);
}

.mobile-nav a:hover {
  color: var(--text);
  background: rgba(255, 255, 255, .04);
  border-color: var(--border);
}

/* ─── Layout & Conteneurs ────────────────────────────────────────── */
.main-content {
  padding-top: var(--nav-h);
  min-height: 100vh;
  position: relative;
  z-index: 1;
}

.container {
  max-width: 1140px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section    { padding: 5rem 0; }
.section-sm { padding: 3rem 0; }

/* Grilles */
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 2rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.25rem; }

/* ─── Typographie ────────────────────────────────────────────────── */
.tag {
  display: inline-flex;
  align-items: center;
  gap: .4rem;
  background: rgba(59, 130, 246, .12);
  border: 1px solid rgba(59, 130, 246, .3);
  color: var(--blue);
  border-radius: 99px;
  padding: .25rem .85rem;
  font-size: .78rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  margin-bottom: 1.2rem;
}

h1 {
  font-size: clamp(2.2rem, 5vw, 3.6rem);
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -.03em;
}

h2 {
  font-size: clamp(1.6rem, 3.5vw, 2.4rem);
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -.02em;
}

h3 { font-size: 1.25rem; font-weight: 700; line-height: 1.3; }
h4 { font-size: 1rem; font-weight: 600; }

.lead {
  font-size: 1.1rem;
  color: var(--muted);
  line-height: 1.75;
  max-width: 660px;
}

.gradient-text {
  background: var(--grad1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.gradient-text-2 {
  background: var(--grad2);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

/* ─── Boutons ────────────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  padding: .75rem 1.75rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: .95rem;
  cursor: pointer;
  border: none;
  transition: all var(--t);
}

.btn-primary {
  background: var(--grad1);
  color: #fff;
  box-shadow: 0 4px 20px rgba(59, 130, 246, .35);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(59, 130, 246, .45);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-outline:hover {
  background: rgba(255, 255, 255, .05);
  border-color: rgba(59, 130, 246, .5);
}

.btn-teal {
  background: linear-gradient(135deg, #14b8a6, #06b6d4);
  color: #fff;
  box-shadow: 0 4px 20px rgba(20, 184, 166, .3);
}

.btn-teal:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 28px rgba(20, 184, 166, .4);
}

.btn-group {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

/* ─── Cards ──────────────────────────────────────────────────────── */
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  transition: border-color var(--t), transform var(--t), box-shadow var(--t);
}

.card:hover {
  border-color: rgba(59, 130, 246, .4);
  transform: translateY(-3px);
  box-shadow: 0 12px 40px rgba(0, 0, 0, .3);
}

.card h3 { margin-bottom: .5rem; }
.card p  { color: var(--muted); font-size: .92rem; }

/* Icône de card */
.card-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 1.1rem;
  font-size: 1.4rem;
}

.card-icon.blue   { background: rgba(59, 130, 246, .15); }
.card-icon.indigo { background: rgba(99, 102, 241, .15); }
.card-icon.teal   { background: rgba(20, 184, 166, .15); }
.card-icon.purple { background: rgba(168, 85, 247, .15); }
.card-icon.orange { background: rgba(249, 115, 22, .15); }

/* ─── Hero (base commune) ────────────────────────────────────────── */
.hero {
  padding: 7rem 0 5rem;
  position: relative;
  overflow: hidden;
}

.hero-content {
  position: relative;
  z-index: 2;
}

.hero h1     { margin-bottom: 1.25rem; }
.hero .lead  { margin-bottom: 2.25rem; }

/* Orbites animées dans le hero */
.hero-orb {
  position: absolute;
  right: -80px;
  top: 50%;
  transform: translateY(-50%);
  width: 500px;
  height: 500px;
  pointer-events: none;
  z-index: 1;
}

.orb-ring {
  position: absolute;
  inset: 0;
  border-radius: 50%;
  border: 1px solid rgba(59, 130, 246, .2);
  animation: spin linear infinite;
}

.orb-ring:nth-child(1) { animation-duration: 20s; }
.orb-ring:nth-child(2) {
  inset: 40px;
  border-color: rgba(99, 102, 241, .25);
  animation-duration: 14s;
  animation-direction: reverse;
}
.orb-ring:nth-child(3) {
  inset: 100px;
  border-color: rgba(20, 184, 166, .2);
  animation-duration: 9s;
}

.orb-core {
  position: absolute;
  inset: 160px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(59,130,246,.35) 0%, rgba(99,102,241,.2) 50%, transparent 80%);
  animation: pulse 4s ease-in-out infinite;
}

.orb-dot {
  position: absolute;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--blue);
  top: 50%; left: 0;
  transform: translateY(-50%);
  box-shadow: 0 0 12px var(--blue);
}

.orb-dot-2 {
  background: var(--indigo);
  left: auto;
  right: 0;
  box-shadow: 0 0 12px var(--indigo);
}

@keyframes spin  { to { transform: rotate(360deg); } }
@keyframes pulse { 0%,100%{transform:scale(1);opacity:.8} 50%{transform:scale(1.08);opacity:1} }

/* ─── En-têtes de sections ───────────────────────────────────────── */
.section-header           { margin-bottom: 3rem; }
.section-header.center    { text-align: center; }
.section-header.center .lead { margin: .75rem auto 0; }
.section-header h2        { margin-bottom: .6rem; }
.section-header p         { color: var(--muted); max-width: 600px; font-size: 1.05rem; }

/* ─── Séparateurs ────────────────────────────────────────────────── */
.divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border), transparent);
}

/* ─── Stats bar ──────────────────────────────────────────────────── */
.stats-bar {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  text-align: center;
}

.stat-item h3 { font-size: 2rem; font-weight: 800; margin-bottom: .2rem; }
.stat-item p  { color: var(--muted); font-size: .85rem; }

/* ─── CTA Banner ─────────────────────────────────────────────────── */
.cta-banner {
  background: linear-gradient(135deg, rgba(59,130,246,.15), rgba(99,102,241,.1));
  border: 1px solid rgba(59, 130, 246, .25);
  border-radius: 20px;
  padding: 3.5rem 3rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at center, rgba(59,130,246,.08) 0%, transparent 70%);
}

.cta-banner > * { position: relative; z-index: 1; }
.cta-banner h2  { margin-bottom: .75rem; }
.cta-banner p   { color: var(--muted); margin-bottom: 2rem; font-size: 1.05rem; }

/* ─── Feature list ───────────────────────────────────────────────── */
.feat-list { list-style: none; }

.feat-list li {
  display: flex;
  align-items: flex-start;
  gap: .75rem;
  padding: .6rem 0;
  color: var(--muted);
  font-size: .95rem;
  border-bottom: 1px solid rgba(255, 255, 255, .04);
}

.feat-list li:last-child { border-bottom: none; }

.feat-list .ico {
  width: 24px; height: 24px;
  border-radius: 6px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: .8rem;
}

.feat-list .ico.blue { background: rgba(59,130,246,.15); color: var(--blue); }
.feat-list .ico.teal { background: rgba(20,184,166,.15); color: var(--teal); }

/* ─── Check list ─────────────────────────────────────────────────── */
.check-list { list-style: none; }

.check-list li {
  padding: .4rem 0;
  font-size: .92rem;
  color: var(--muted);
  display: flex;
  align-items: flex-start;
  gap: .6rem;
}

.check-list li::before     { content: '✗'; color: #f87171; flex-shrink: 0; }
.check-list.ok li::before  { content: '✓'; color: #34d399; }

/* ─── Timeline ───────────────────────────────────────────────────── */
.timeline {
  position: relative;
  padding-left: 2rem;
}

.timeline::before {
  content: '';
  position: absolute;
  left: 8px; top: 0; bottom: 0;
  width: 2px;
  background: var(--border);
}

.timeline-item {
  position: relative;
  padding-bottom: 2rem;
}

.timeline-dot {
  position: absolute;
  left: -1.85rem; top: 4px;
  width: 14px; height: 14px;
  border-radius: 50%;
  background: var(--blue);
  border: 2px solid var(--bg);
  box-shadow: 0 0 10px rgba(59, 130, 246, .5);
}

.timeline-item h4 { font-size: 1rem; margin-bottom: .3rem; }
.timeline-item p  { color: var(--muted); font-size: .9rem; }

/* ─── Use case cards ─────────────────────────────────────────────── */
.usecase-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}

.usecase-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: all var(--t);
}

.usecase-card:hover {
  border-color: rgba(59, 130, 246, .4);
  transform: translateY(-2px);
}

.usecase-icon { font-size: 1.8rem; margin-bottom: .75rem; }
.usecase-card h4 { margin-bottom: .35rem; font-size: .95rem; }
.usecase-card p  { color: var(--muted); font-size: .86rem; }

/* ─── Citation philosophique ─────────────────────────────────────── */
.philosophy-quote {
  border-left: 3px solid var(--blue);
  padding: 1.5rem 2rem;
  background: rgba(59, 130, 246, .06);
  border-radius: 0 12px 12px 0;
  font-size: 1.05rem;
  font-style: italic;
  color: var(--text);
  line-height: 1.75;
}

/* ─── Vision card ────────────────────────────────────────────────── */
.vision-card {
  background: linear-gradient(135deg, var(--card), rgba(99, 102, 241, .1));
  border: 1px solid rgba(99, 102, 241, .3);
  border-radius: 20px;
  padding: 3rem;
}

/* ─── Scroll reveal ──────────────────────────────────────────────── */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity .5s ease, transform .5s ease;
}

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

/* ─── Footer ─────────────────────────────────────────────────────── */
footer {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 3rem 0 2rem;
  position: relative;
  z-index: 1;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 2.5rem;
}

.footer-brand p {
  color: var(--muted);
  font-size: .9rem;
  margin-top: .75rem;
  max-width: 260px;
  line-height: 1.65;
}

.footer-col h5 {
  font-size: .85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--dim);
  margin-bottom: 1rem;
}

.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: .5rem; }

.footer-col a {
  color: var(--muted);
  font-size: .9rem;
  transition: color var(--t);
}

.footer-col a:hover { color: var(--text); }

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--dim);
  font-size: .83rem;
}

/* ─── Responsive ─────────────────────────────────────────────────── */
@media (max-width: 1024px) {
  .grid-3    { grid-template-columns: 1fr 1fr; }
  .grid-4    { grid-template-columns: repeat(2, 1fr); }
  .stats-bar { grid-template-columns: 1fr 1fr; }
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 2rem; }
}

@media (max-width: 768px) {
  .nav-links      { display: none; }
  .nav-mobile-btn { display: block; }

  .hero { padding: 5rem 0 3rem; }
  .hero-orb { display: none; }

  h1 { font-size: 2rem; }

  .grid-2    { grid-template-columns: 1fr; }
  .grid-3    { grid-template-columns: 1fr; }
  .usecase-grid { grid-template-columns: 1fr; }

  .section    { padding: 3rem 0; }
  .cta-banner { padding: 2.5rem 1.5rem; }

  .footer-grid { grid-template-columns: 1fr; gap: 1.5rem; }
}