/* ==============================================================
   RESEARCH & DEVELOPMENT PAGE – FULL STYLE (no reductions)
   ============================================================== */
:root{
  --primary:#1E3F5C;
  --primary-light:#37a2b5;
  --secondary:#1E3F5C;
  --secondary-dark:#0b233e;
  --text-dark:#111827;
  --text-light:#f1f2f5;
  --bg-light:#f5f8fb;
  --border:#e5e8ed;
  --shadow:0 4px 20px rgba(0,0,0,.08);
  --transition:all .3s ease;
  --nav-height:80px;
  --nav-h:80px;
}

/* ---------- Base ---------- */
*{margin:0;padding:0;box-sizing:border-box}
body{
  font-family:'Inter',system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif;
  background:var(--bg-light);
  color:var(--text-dark);
  line-height:1.6;
  overflow-x:hidden;
  padding-top:var(--nav-height);
}
.container{width:min(1200px,92%);margin-inline:auto}

/* ---------- NAVBAR ---------- */
.site-header{
  position:fixed;top:0;left:0;width:100%;height:var(--nav-h);z-index:1000;
  background:rgba(255,255,255,.97);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--border);transition:var(--transition);
}
.site-header.scrolled{background:rgba(255,255,255,.99)}

.nav{
  height:var(--nav-h);display:flex;align-items:center;justify-content:space-between;
  padding-left:clamp(8px,1.2vw,16px);padding-right:3vw;
}
.nav-brand-wrap{flex:0 0 auto;display:flex;align-items:center;justify-content:flex-start}
.brand .logo{
  height:600px;width:auto;object-fit:contain;margin-top:11%;display:block;
  transform:translateX(-80px);
}
.nav-links-wrap{flex:1;display:flex;align-items:center;justify-content:flex-end}
.nav-links{display:flex;list-style:none;gap:36px;align-items:center}
.nav-link{
  font-weight:600;color:var(--text-dark);position:relative;padding:5px 0;
  transition:var(--transition);text-decoration:none;
}
.nav-link::after{
  content:"";position:absolute;bottom:-3px;left:0;width:0;height:2px;
  background:var(--primary);transition:width .3s ease;
}
.nav-link:hover::after,.nav-link.active::after{width:100%}
.nav-link:hover,.nav-link.active{color:var(--primary)}

.dropdown{position:relative}
.dropdown-menu{
  position:absolute;left:0;top:calc(100% + 10px);background:#fff;
  border:1px solid var(--border);border-radius:10px;box-shadow:var(--shadow);
  min-width:260px;list-style:none;padding:10px 0;opacity:0;visibility:hidden;
  transform:translateY(6px);transition:var(--transition);z-index:1001;
}
.dropdown:hover .dropdown-menu{opacity:1;visibility:visible;transform:translateY(0)}
.dropdown-link{
  display:block;padding:10px 14px;font-weight:600;color:var(--text-dark);
  text-decoration:none;
}
.dropdown-link:hover,.dropdown-link.active{background:var(--bg-light);color:var(--primary)}

.mobile-menu-btn{
  display:none;background:none;border:none;font-size:1.5rem;color:var(--text-dark);cursor:pointer;
}

/* ---------- Mobile Navbar ---------- */
@media (max-width:768px){
  .mobile-menu-btn{
    display:flex;align-items:center;justify-content:center;
    font-size:clamp(1.25rem,4vw,1.5rem);padding:clamp(4px,1vw,8px);
    min-width:clamp(36px,9vw,44px);min-height:clamp(36px,9vw,44px);
  }
  .nav-links{
    display:none;position:fixed;top:var(--nav-h);left:0;right:0;width:100%;
    background:#fff;flex-direction:column;align-items:stretch;
    padding:clamp(16px,4vw,24px);box-shadow:0 4px 20px rgba(0,0,0,.1);
    gap:0;z-index:999;max-height:calc(100vh - var(--nav-h));overflow-y:auto;
  }
  .nav-links.active{display:flex}
  .nav-link{width:100%;padding:clamp(10px,2.5vw,14px) 0;text-align:left;
            font-size:clamp(0.9rem,3vw,1rem)}
  .dropdown>.nav-link{width:100%}
  .dropdown .dropdown-menu{
    position:static;transform:none;border:1px solid var(--border);
    border-radius:clamp(6px,1.5vw,8px);margin-top:clamp(6px,1.5vw,8px);
    width:100%;opacity:0;visibility:hidden;max-height:0;overflow:hidden;
    transition:opacity .3s ease,max-height .3s ease;
  }
  .dropdown.open .dropdown-menu{opacity:1;visibility:visible;max-height:500px}
  .dropdown-link{padding:clamp(8px,2vw,12px) clamp(12px,3vw,16px);
                 font-size:clamp(0.85rem,2.5vw,0.95rem)}
}

/* ---------- HERO ---------- */
.hero{
  min-height:100vh;background:url('https://images.unsplash.com/photo-1451187580459-43490279c0fa?ixlib=rb-4.0.3&auto=format&fit=crop&w=1920&q=80')
  center/cover no-repeat;position:relative;display:flex;align-items:center;
  justify-content:center;text-align:center;
}
.hero::before{
  content:'';position:absolute;inset:0;background:rgba(10,37,64,.75);
}
.hero-content{
  position:relative;z-index:2;max-width:900px;padding:2rem;
}
.hero h1{
  font-size:3.8rem;font-weight:700;margin-bottom:1rem;
  text-shadow:2px 2px 6px rgba(0,0,0,.6);color:#fff;
}
.hero p{
  font-size:1.35rem;margin-bottom:2rem;opacity:.92;color:#fff;
}
.btn-primary{
  display:inline-block;padding:1rem 2.2rem;background:#E31C2D;color:#fff;
  border-radius:6px;font-weight:600;font-size:1.1rem;transition:all .3s ease;
  text-decoration:none;
}
.btn-primary:hover{
  background:#C41224;transform:translateY(-3px);
  box-shadow:0 8px 20px rgba(227,28,45,.3);
}

/* ---------- SECTION COMMON ---------- */
.section-light{background:var(--bg-light);padding:80px 0}
h2{
  font-size:2.5rem;text-align:center;margin-bottom:3rem;position:relative;
}
h2::after{
  content:'';position:absolute;bottom:-15px;left:50%;transform:translateX(-50%);
  width:80px;height:4px;background:var(--primary-light);
}

/* ---------- INTRODUCTION (larger text) ---------- */
.challenge-section p{
  font-size:1.28rem !important;line-height:1.9;color:#1a1a1a;
  max-width:850px;margin:0 auto 1.5rem;
}
.intro-content{display:flex;align-items:center;gap:40px;flex-wrap:wrap}
.intro-text{flex:1;min-width:300px}
.intro-image{
  flex:0 0 380px;height:300px;border-radius:12px;overflow:hidden;
  box-shadow:0 15px 30px rgba(0,0,0,.12);
}
.intro-image img{
  width:100%;height:100%;object-fit:cover;transition:var(--transition);
}
.intro-image:hover img{transform:scale(1.06)}

/* ---------- 2×2 SERVICE GRID – SLIDE-UP ---------- */
.services-grid-2x2{
  display:grid;grid-template-columns:1fr 1fr;gap:30px;
  max-width:1000px;margin:0 auto;
}
.service-card{
  position:relative;height:380px;border-radius:16px;overflow:hidden;
  box-shadow:0 8px 25px rgba(0,0,0,.15);transition:transform .4s ease;cursor:pointer;
}
.service-bg{
  position:absolute;top:0;left:0;width:100%;height:100%;
  background-size:cover;background-position:center;
  transition:transform .5s ease;z-index:1;
}
.service-content{
  position:absolute;bottom:0;left:0;width:100%;padding:30px;
  color:#fff;text-align:center;transform:translateY(70%);
  transition:transform .5s ease;z-index:2;
}
.service-icon{
  font-size:3rem;margin-bottom:15px;color:#fff;
  text-shadow:0 2px 5px rgba(0,0,0,.3);
}
.service-card h3{
  font-size:1.7rem;margin-bottom:12px;font-weight:700;
}
.service-card p{
  font-size:1.05rem;line-height:1.6;opacity:.9;
}
.service-card:hover .service-content{transform:translateY(0)}
.service-card:hover .service-bg{transform:scale(1.05)}

/* ---------- RESPONSIVE ---------- */
@media (max-width:768px){
  .services-grid-2x2{grid-template-columns:1fr}
  .service-card{height:340px}
  .challenge-section p{font-size:1.15rem !important}
  .intro-content{flex-direction:column;text-align:center;gap:30px}
  .intro-image{flex:0 0 280px;height:220px;max-width:100%}
}

/* ---------- FADE-IN ON SCROLL ---------- */
.fade-in{opacity:0;transform:translateY(20px);transition:opacity .6s ease,transform .6s ease}
.fade-in.visible{opacity:1;transform:translateY(0)}

/* ---------- FOOTER ---------- */
footer{
  background:linear-gradient(135deg,var(--secondary) 0%,var(--secondary-dark) 100%);
  color:var(--text-light);padding-top:60px;
}
.footer-content{
  display:grid;grid-template-columns:repeat(4,1fr);gap:40px;padding-bottom:40px;
}
.footer-col h3{
  color:var(--primary-light);font-size:1.25rem;margin-bottom:20px;
  position:relative;padding-bottom:10px;
}
.footer-col h3::after{
  content:"";position:absolute;bottom:0;left:0;width:40px;height:2px;
  background:var(--primary-light);
}
.footer-col p{margin-bottom:15px;opacity:.9}
.footer-links{list-style:none}
.footer-links li{margin-bottom:10px}
.footer-links a{opacity:.9;transition:var(--transition);color:inherit;text-decoration:none}
.footer-links a:hover{opacity:1;color:var(--primary-light);padding-left:5px}
.footer-social{display:flex;gap:15px;margin-top:20px}
.social-icon{
  display:flex;align-items:center;justify-content:center;width:40px;height:40px;
  border-radius:50%;background:rgba(255,255,255,.1);color:#fff;transition:var(--transition);
}
.social-icon:hover{background:var(--primary);transform:translateY(-3px)}
.footer-bottom{
  border-top:1px solid rgba(255,255,255,.1);padding:20px 0;
  text-align:center;font-size:.9rem;opacity:.7;
}

/* Footer responsive */
@media (max-width:1024px){.footer-content{grid-template-columns:repeat(2,1fr)}}
@media (max-width:768px){
  .footer-content{grid-template-columns:1fr;text-align:center;justify-items:center}
  .footer-col h3::after{left:50%;transform:translateX(-50%)}
  .footer-social{justify-content:center}
  .footer-links a:hover{padding-left:0}
}