/* =========================================================
   NICS Lab - Korea Aerospace University
   Common Stylesheet
   ========================================================= */

:root{
  --navy-900:#081d3f;
  --navy-800:#0a2c66;
  --navy-700:#123a7d;
  --navy-600:#1e4d8c;
  --blue-500:#3a6ea5;
  --blue-400:#5b8fc7;
  --gold-500:#c9a227;
  --gold-400:#e0bc4a;
  --ink-900:#111827;
  --ink-700:#374151;
  --ink-500:#6b7280;
  --bg-light:#f5f7fb;
  --white:#ffffff;
  --border:#e3e8f0;
  --radius:14px;
  --shadow-sm:0 2px 8px rgba(10,44,102,0.08);
  --shadow-md:0 8px 24px rgba(10,44,102,0.12);
  --shadow-lg:0 16px 40px rgba(10,44,102,0.18);
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  font-family:'Noto Sans KR','Pretendard',-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;
  color:var(--ink-900);
  background:var(--bg-light);
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
a{color:inherit;text-decoration:none;}
img{max-width:100%;display:block;}
ul{list-style:none;margin:0;padding:0;}
h1,h2,h3,h4{margin:0;font-weight:700;letter-spacing:-0.01em;}
p{margin:0;}
.container{max-width:1180px;margin:0 auto;padding:0 24px;}

/* ---------- Top bar ---------- */
.top-bar{
  background:var(--navy-900);
  color:#cdd9ee;
  font-size:12.5px;
}
.top-bar .container{
  display:flex;justify-content:space-between;align-items:center;
  height:34px;
}
.top-bar a{opacity:.85;}
.top-bar a:hover{opacity:1;text-decoration:underline;}

/* ---------- Header / Nav ---------- */
.site-header{
  background:rgba(255,255,255,0.97);
  position:sticky;top:0;z-index:200;
  border-bottom:1px solid var(--border);
  backdrop-filter:blur(6px);
}
.site-header .container{
  display:flex;align-items:center;justify-content:space-between;
  height:76px;
}
.brand{display:flex;align-items:center;gap:12px;}
.brand-mark{
  width:46px;height:46px;border-radius:10px;
  background:linear-gradient(135deg,var(--navy-800),var(--blue-500));
  display:flex;align-items:center;justify-content:center;
  color:#fff;font-weight:800;font-size:15px;letter-spacing:0.5px;
  box-shadow:var(--shadow-sm);
  flex-shrink:0;
}
.brand-text{display:flex;flex-direction:column;line-height:1.25;}
.brand-text strong{font-size:19px;color:var(--navy-900);letter-spacing:-0.02em;}
.brand-text span{font-size:11.5px;color:var(--ink-500);font-weight:500;}

.main-nav{display:flex;align-items:center;gap:2px;}
.main-nav a{
  padding:10px 16px;font-size:15px;font-weight:600;color:var(--ink-700);
  border-radius:8px;transition:background .15s,color .15s;
  white-space:nowrap;
}
.main-nav a:hover{background:var(--bg-light);color:var(--navy-800);}
.main-nav a.active{color:var(--navy-800);background:#eaf0fb;}

.nav-toggle{
  display:none;background:none;border:none;cursor:pointer;
  width:40px;height:40px;align-items:center;justify-content:center;
  border-radius:8px;
}
.nav-toggle:hover{background:var(--bg-light);}
.nav-toggle span{display:block;width:22px;height:2px;background:var(--navy-900);position:relative;}
.nav-toggle span::before,.nav-toggle span::after{
  content:"";position:absolute;left:0;width:22px;height:2px;background:var(--navy-900);
}
.nav-toggle span::before{top:-7px;}
.nav-toggle span::after{top:7px;}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  padding:12px 24px;border-radius:999px;font-weight:700;font-size:15px;
  border:2px solid transparent;cursor:pointer;transition:all .2s;
}
.btn-primary{background:var(--gold-500);color:var(--navy-900);}
.btn-primary:hover{background:var(--gold-400);transform:translateY(-2px);box-shadow:var(--shadow-md);}
.btn-outline{border-color:rgba(255,255,255,0.6);color:#fff;}
.btn-outline:hover{background:rgba(255,255,255,0.12);transform:translateY(-2px);}
.btn-navy{background:var(--navy-800);color:#fff;}
.btn-navy:hover{background:var(--navy-700);transform:translateY(-2px);box-shadow:var(--shadow-md);}

/* ---------- Hero (page banner) ---------- */
.page-hero{
  position:relative;color:#fff;padding:76px 0 60px;
  background:linear-gradient(120deg,rgba(8,29,63,.92),rgba(18,58,125,.88));
  overflow:hidden;
}
.page-hero::after{
  content:"";position:absolute;inset:0;
  background:radial-gradient(circle at 85% 20%, rgba(201,162,39,.25), transparent 55%);
  pointer-events:none;
}
.page-hero .container{position:relative;z-index:1;}
.eyebrow{
  display:inline-block;font-size:13px;font-weight:700;letter-spacing:0.12em;
  color:var(--gold-400);text-transform:uppercase;margin-bottom:14px;
}
.page-hero h1{font-size:38px;margin-bottom:14px;}
.page-hero p.lead{font-size:16.5px;color:#d7e2f5;max-width:640px;}
.breadcrumb{margin-top:22px;font-size:13.5px;color:#b7c6e6;}
.breadcrumb a:hover{color:#fff;text-decoration:underline;}

/* ---------- Sections ---------- */
section{padding:76px 0;}
.section-head{max-width:680px;margin:0 auto 44px;text-align:center;}
.section-head h2{font-size:30px;color:var(--navy-900);margin-bottom:12px;}
.section-head p{color:var(--ink-500);font-size:15.5px;}
.section-head.align-left{margin:0 0 40px;text-align:left;}

.tag{
  display:inline-block;background:#eaf0fb;color:var(--navy-700);
  font-size:12.5px;font-weight:700;padding:5px 12px;border-radius:999px;
  letter-spacing:.02em;
}

/* ---------- Cards (grid) ---------- */
.grid{display:grid;gap:26px;}
.grid-3{grid-template-columns:repeat(3,1fr);}
.grid-2{grid-template-columns:repeat(2,1fr);}
.grid-4{grid-template-columns:repeat(4,1fr);}

.card{
  background:#fff;border-radius:var(--radius);border:1px solid var(--border);
  box-shadow:var(--shadow-sm);transition:transform .2s,box-shadow .2s;overflow:hidden;
}
.card:hover{transform:translateY(-4px);box-shadow:var(--shadow-md);}
.card-body{padding:26px;}
.card-icon{
  width:52px;height:52px;border-radius:12px;background:linear-gradient(135deg,var(--navy-800),var(--blue-500));
  display:flex;align-items:center;justify-content:center;color:#fff;font-size:22px;margin-bottom:18px;
}
.card h3{font-size:19px;color:var(--navy-900);margin-bottom:10px;}
.card p{color:var(--ink-500);font-size:14.5px;}

/* ---------- Footer ---------- */
.site-footer{background:var(--navy-900);color:#aebada;padding:56px 0 0;}
.footer-grid{
  display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:36px;padding-bottom:40px;
  border-bottom:1px solid rgba(255,255,255,0.1);
}
.footer-grid h4{color:#fff;font-size:15px;margin-bottom:16px;}
.footer-grid li{margin-bottom:10px;font-size:14px;}
.footer-grid a:hover{color:#fff;}
.footer-brand{display:flex;align-items:center;gap:10px;margin-bottom:14px;}
.footer-brand strong{color:#fff;font-size:17px;}
.footer-desc{font-size:13.5px;line-height:1.7;color:#93a2c6;max-width:320px;}
.footer-bottom{
  display:flex;justify-content:space-between;align-items:center;
  padding:20px 0;font-size:12.5px;color:#7c8cb2;flex-wrap:wrap;gap:8px;
}
.social-row{display:flex;gap:10px;}
.social-row a{
  width:34px;height:34px;border-radius:999px;background:rgba(255,255,255,0.08);
  display:flex;align-items:center;justify-content:center;font-size:14px;
}
.social-row a:hover{background:var(--gold-500);color:var(--navy-900);}

/* ---------- Utility ---------- */
.mt-0{margin-top:0;}
.text-center{text-align:center;}
.stack{display:flex;flex-direction:column;gap:10px;}
.hr-line{height:1px;background:var(--border);margin:36px 0;}

/* Loading / empty state */
.state-msg{
  text-align:center;padding:40px 20px;color:var(--ink-500);font-size:14.5px;
}

/* ---------- Responsive ---------- */
@media (max-width:960px){
  .grid-3{grid-template-columns:repeat(2,1fr);}
  .grid-4{grid-template-columns:repeat(2,1fr);}
  .footer-grid{grid-template-columns:1fr 1fr;}
}
@media (max-width:720px){
  .main-nav{
    position:fixed;top:76px;left:0;right:0;bottom:0;background:#fff;
    flex-direction:column;align-items:stretch;padding:16px;gap:4px;
    transform:translateX(100%);transition:transform .25s ease;overflow-y:auto;
  }
  .main-nav.open{transform:translateX(0);}
  .main-nav a{padding:14px 16px;font-size:16px;border-bottom:1px solid var(--border);border-radius:0;}
  .nav-toggle{display:flex;}
  .top-bar{display:none;}
  .page-hero h1{font-size:28px;}
  .grid-3,.grid-2,.grid-4{grid-template-columns:1fr;}
  .footer-grid{grid-template-columns:1fr;}
  section{padding:52px 0;}
}