/* ============================================================
   Dr. Gokulakrishnan S — Academic Portfolio Design System
   ============================================================ */
:root {
  --primary: #1B3A6B;
  --primary-dark: #142C52;
  --accent: #B8860B;
  --primary-soft: rgba(27, 58, 107, 0.08);
  --background: #FAFAFA;
  --surface: #FFFFFF;
  --surface-2: #F2F4F7;
  --text: #1A1D23;
  --muted: #5B6472;
  --border: #E1E4E9;
  --shadow: 0 2px 8px rgba(20,30,50,0.08), 0 8px 24px rgba(20,30,50,0.06);
  --shadow-sm: 0 1px 4px rgba(20,30,50,0.10);
  --radius: 14px;
  --radius-sm: 9px;
  --maxw: 1180px;
  font-size: 16px;
}
* { box-sizing: border-box; }
html, body { margin:0; padding:0; background:var(--background); color:var(--text); font-family:'Inter',-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif; line-height:1.6; }
h1,h2,h3,.serif { font-family:'Merriweather',Georgia,serif; }
a { color:inherit; text-decoration:none; }
img,video { max-width:100%; display:block; }
button,input,textarea,select { font-family:inherit; font-size:1rem; }
:focus-visible { outline:2px solid var(--primary); outline-offset:2px; }
.container { max-width:var(--maxw); margin:0 auto; padding:0 20px; }

/* Nav */
.site-header { position:sticky; top:0; z-index:50; background:rgba(255,255,255,0.95); backdrop-filter:blur(10px); border-bottom:1px solid var(--border); }
.site-header .inner { display:flex; align-items:center; justify-content:space-between; padding:14px 20px; max-width:var(--maxw); margin:0 auto; gap:16px; flex-wrap:wrap; }
.brand { display:flex; align-items:center; gap:10px; font-weight:700; font-size:1.1rem; font-family:'Merriweather',serif; }
.brand .dot { width:36px; height:36px; border-radius:50%; background:var(--primary); display:flex; align-items:center; justify-content:center; font-size:1rem; color:white; }
.main-nav { display:flex; gap:2px; flex-wrap:wrap; }
.main-nav a { padding:8px 12px; border-radius:999px; font-size:0.88rem; font-weight:600; color:var(--muted); }
.main-nav a:hover, .main-nav a.active { color:var(--primary); background:var(--primary-soft); }

.btn { display:inline-flex; align-items:center; gap:8px; padding:10px 18px; border-radius:999px; border:1px solid var(--border); background:var(--surface); color:var(--text); font-weight:600; font-size:0.88rem; cursor:pointer; transition:all 0.15s ease; }
.btn:hover { border-color:var(--primary); box-shadow:var(--shadow-sm); }
.btn-primary { background:var(--primary); border:none; color:white; }
.btn-primary:hover { background:var(--primary-dark); }
.btn-accent { background:var(--accent); border:none; color:white; }
.btn-danger { background:#FCE8E6; border-color:#F6C6C2; color:#C5221F; }
.btn-sm { padding:6px 13px; font-size:0.8rem; }
.btn-block { width:100%; justify-content:center; }

/* Hero */
.hero { padding:56px 0 40px; }
.hero-grid { display:grid; grid-template-columns:200px 1fr; gap:36px; align-items:center; }
.hero-photo { width:200px; height:200px; border-radius:50%; object-fit:cover; box-shadow:var(--shadow); border:4px solid var(--surface); }
.hero-eyebrow { color:var(--accent); font-weight:700; font-size:0.85rem; text-transform:uppercase; letter-spacing:0.06em; margin-bottom:6px; }
.hero h1 { font-size:clamp(1.8rem,4vw,2.6rem); margin:0 0 8px; }
.hero .tagline { color:var(--muted); font-size:1.05rem; margin:0 0 4px; }
.hero .dept { color:var(--muted); font-size:0.9rem; margin:0 0 18px; }
.hero-actions { display:flex; gap:10px; flex-wrap:wrap; }
.hero-social { display:flex; gap:8px; flex-wrap:wrap; margin-top:16px; }
.hero-social a { padding:6px 12px; border-radius:999px; background:var(--surface-2); font-size:0.78rem; font-weight:600; color:var(--muted); }
.hero-social a:hover { color:var(--primary); }

@media (max-width:640px) { .hero-grid { grid-template-columns:1fr; text-align:center; } .hero-photo { margin:0 auto; } .hero-social { justify-content:center; } .hero-actions { justify-content:center; } }

/* Section */
.section { padding:44px 0; border-top:1px solid var(--border); }
.section-head { margin-bottom:24px; }
.section-head h2 { font-size:clamp(1.4rem,2.4vw,1.8rem); margin:0 0 6px; }
.section-head p { color:var(--muted); margin:0; }

/* Timeline (education/experience) */
.tl { position:relative; padding-left:26px; }
.tl::before { content:''; position:absolute; left:6px; top:6px; bottom:6px; width:2px; background:var(--border); }
.tl-item { position:relative; margin-bottom:22px; }
.tl-item::before { content:''; position:absolute; left:-23px; top:5px; width:11px; height:11px; border-radius:50%; background:var(--primary); border:2px solid var(--background); }
.tl-item h3 { margin:0 0 2px; font-size:1.05rem; }
.tl-item .meta { color:var(--muted); font-size:0.85rem; }
.tl-item .extra { color:var(--accent); font-size:0.8rem; font-weight:600; margin-top:2px; }

/* Subjects */
.subject-groups { display:grid; grid-template-columns:repeat(auto-fit,minmax(220px,1fr)); gap:18px; }
.subject-group h4 { margin:0 0 10px; font-size:0.95rem; color:var(--primary); }
.subject-chips { display:flex; flex-wrap:wrap; gap:6px; }
.subject-chips span { background:var(--surface-2); padding:5px 12px; border-radius:999px; font-size:0.8rem; }

/* Publications tabs */
.pub-tabs { display:flex; gap:6px; flex-wrap:wrap; margin-bottom:20px; }
.pub-tab { padding:8px 16px; border-radius:999px; border:1px solid var(--border); background:var(--surface); font-size:0.83rem; font-weight:600; color:var(--muted); cursor:pointer; }
.pub-tab.active { background:var(--primary); color:white; border-color:transparent; }
.pub-panel { display:none; }
.pub-panel.active { display:block; }
.pub-item { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); padding:16px 18px; margin-bottom:10px; }
.pub-item .year-badge { display:inline-block; background:var(--primary-soft); color:var(--primary); font-size:0.72rem; font-weight:700; padding:2px 10px; border-radius:999px; margin-right:6px; }
.pub-item .tag-badge { display:inline-block; background:var(--surface-2); color:var(--muted); font-size:0.72rem; font-weight:600; padding:2px 10px; border-radius:999px; }
.pub-item h4 { margin:8px 0 4px; font-size:0.98rem; line-height:1.4; }
.pub-item .authors { color:var(--muted); font-size:0.85rem; margin:0 0 2px; }
.pub-item .venue { color:var(--accent); font-size:0.82rem; font-style:italic; }
.pub-item .ref { color:var(--muted); font-size:0.78rem; margin-top:4px; }
.pub-item a.proof-link { font-size:0.78rem; font-weight:600; color:var(--primary); margin-top:6px; display:inline-block; }

/* Awards / certifications / memberships grids */
.award-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(240px,1fr)); gap:14px; }
.award-card { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); padding:18px; text-align:center; }
.award-card .icon { font-size:1.8rem; margin-bottom:8px; }
.award-card h4 { margin:0 0 4px; font-size:0.95rem; }
.award-card p { margin:0; color:var(--muted); font-size:0.82rem; }
.award-card a { font-size:0.78rem; color:var(--primary); font-weight:600; margin-top:6px; display:inline-block; }

.cert-list { display:grid; grid-template-columns:repeat(auto-fit,minmax(260px,1fr)); gap:10px; }
.cert-item { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); padding:12px 16px; }
.cert-item .t { font-weight:600; font-size:0.9rem; }
.cert-item .i { color:var(--muted); font-size:0.8rem; }
.cert-item a { font-size:0.76rem; color:var(--primary); font-weight:600; }

/* Gallery */
.gallery-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(200px,1fr)); gap:12px; }
.gallery-grid .g-item { border-radius:var(--radius-sm); overflow:hidden; aspect-ratio:4/3; position:relative; cursor:pointer; }
.gallery-grid .g-item img { width:100%; height:100%; object-fit:cover; transition:transform 0.2s ease; }
.gallery-grid .g-item:hover img { transform:scale(1.05); }
.gallery-grid .g-item .cap { position:absolute; bottom:0; left:0; right:0; background:linear-gradient(to top,rgba(0,0,0,0.7),transparent); color:white; font-size:0.78rem; padding:16px 10px 8px; opacity:0; transition:opacity 0.2s ease; }
.gallery-grid .g-item:hover .cap { opacity:1; }

/* Videos */
.video-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(260px,1fr)); gap:16px; }
.video-card { border-radius:var(--radius-sm); overflow:hidden; background:var(--surface); border:1px solid var(--border); }
.video-card .v-wrap { aspect-ratio:16/9; background:#000; }
.video-card .v-wrap iframe, .video-card .v-wrap video { width:100%; height:100%; }
.video-card .v-title { padding:10px 14px; font-weight:600; font-size:0.9rem; }

/* Events */
.event-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(280px,1fr)); gap:16px; }
.event-card { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); overflow:hidden; }
.event-card .e-img { aspect-ratio:16/9; background:var(--surface-2); }
.event-card .e-img img { width:100%; height:100%; object-fit:cover; }
.event-card .e-body { padding:14px 16px; }
.event-card .e-date { color:var(--accent); font-weight:700; font-size:0.78rem; text-transform:uppercase; letter-spacing:0.03em; }
.event-card h4 { margin:6px 0; font-size:1rem; }
.event-card .e-loc { color:var(--muted); font-size:0.82rem; }
.event-card p { color:var(--muted); font-size:0.85rem; margin:8px 0 0; }
.event-badge { display:inline-block; padding:2px 10px; border-radius:999px; font-size:0.7rem; font-weight:700; }
.event-badge.upcoming { background:#E6F4EA; color:#137333; }
.event-badge.past { background:var(--surface-2); color:var(--muted); }

.empty-state { text-align:center; padding:50px 20px; color:var(--muted); }
.empty-state .big { font-size:2.2rem; margin-bottom:10px; }

/* Contact */
.contact-grid { display:grid; grid-template-columns:1fr 1fr; gap:30px; }
.contact-grid h4 { margin:0 0 10px; font-size:0.95rem; color:var(--primary); }
.contact-grid .row { margin-bottom:8px; font-size:0.9rem; }
@media (max-width:640px) { .contact-grid { grid-template-columns:1fr; } }

.site-footer { text-align:center; padding:30px 20px; color:var(--muted); font-size:0.82rem; border-top:1px solid var(--border); margin-top:20px; }

/* Auth */
.auth-wrap { min-height:100vh; display:flex; align-items:center; justify-content:center; padding:20px; background:var(--background); }
.auth-card { width:100%; max-width:400px; background:var(--surface); border:1px solid var(--border); border-radius:var(--radius); padding:32px; box-shadow:var(--shadow); }
.field { margin-bottom:16px; }
.field label { display:block; font-size:0.83rem; color:var(--muted); margin-bottom:6px; font-weight:600; }
.field input, .field select, .field textarea { width:100%; padding:11px 14px; background:var(--surface-2); border:1px solid var(--border); border-radius:var(--radius-sm); color:var(--text); }
.field input:focus, .field select:focus, .field textarea:focus { outline:none; border-color:var(--primary); background:var(--surface); }
.alert { padding:11px 16px; border-radius:var(--radius-sm); font-size:0.85rem; margin-bottom:16px; }
.alert-error { background:#FCE8E6; color:#C5221F; border:1px solid #F6C6C2; }
.alert-success { background:#E6F4EA; color:#137333; border:1px solid #C6E7CE; }

/* Admin shell */
.admin-shell { display:flex; min-height:100vh; }
.admin-sidebar { width:230px; flex-shrink:0; background:var(--surface); border-right:1px solid var(--border); padding:20px 14px; }
.admin-sidebar .brand { padding:0 8px 20px; }
.admin-sidebar nav a { display:block; padding:9px 12px; border-radius:var(--radius-sm); font-size:0.85rem; font-weight:600; color:var(--muted); margin-bottom:2px; }
.admin-sidebar nav a:hover { background:var(--surface-2); color:var(--text); }
.admin-sidebar nav a.active { background:var(--primary-soft); color:var(--primary); }
.nav-group-label { font-size:0.66rem; text-transform:uppercase; letter-spacing:0.05em; color:var(--muted); margin:14px 8px 6px; }
.admin-main { flex:1; min-width:0; }
.admin-bar { background:var(--surface); border-bottom:1px solid var(--border); }
.admin-bar .inner { max-width:1400px; margin:0 auto; padding:12px 24px; display:flex; justify-content:space-between; align-items:center; flex-wrap:wrap; gap:10px; }
.admin-greeting { padding:22px 0 4px; }
.admin-greeting h1 { font-size:1.4rem; margin:0 0 4px; }
.admin-greeting p { color:var(--muted); margin:0; }
.admin-stats { display:grid; grid-template-columns:repeat(auto-fit,minmax(140px,1fr)); gap:10px; margin:18px 0; }
.admin-stat-card { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); padding:14px; }
.admin-stat-card .num { font-size:1.5rem; font-weight:700; font-family:'Merriweather',serif; }
.admin-stat-card .label { color:var(--muted); font-size:0.78rem; margin-top:2px; }
.pill { padding:5px 13px; border-radius:999px; background:var(--surface); border:1px solid var(--border); font-size:0.78rem; }
.section-title { font-size:1.05rem; font-weight:700; margin:30px 0 12px; }
.admin-form-card { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); padding:20px; max-width:640px; }
.admin-table { width:100%; border-collapse:collapse; margin-top:10px; background:var(--surface); border-radius:var(--radius-sm); overflow:hidden; }
.admin-table th, .admin-table td { padding:10px 12px; text-align:left; border-bottom:1px solid var(--border); font-size:0.85rem; }
.admin-table th { color:var(--muted); font-weight:600; background:var(--surface-2); }
.quick-links-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(150px,1fr)); gap:12px; }
.quick-link-card { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); padding:20px 10px; text-align:center; font-weight:600; font-size:0.85rem; line-height:1.8; }
.quick-link-card:hover { border-color:var(--primary); box-shadow:var(--shadow-sm); }
.admin-photo-grid { display:grid; grid-template-columns:repeat(auto-fill,minmax(160px,1fr)); gap:12px; }
.admin-photo-tile { background:var(--surface); border:1px solid var(--border); border-radius:var(--radius-sm); overflow:hidden; }
.admin-photo-tile img { width:100%; aspect-ratio:1/1; object-fit:cover; }

.mobile-nav-toggle { display:none; background:none; border:none; font-size:1.4rem; cursor:pointer; color:var(--text); padding:4px 8px; }

@media (max-width:768px) {
  .admin-shell { flex-direction:column; }
  .admin-sidebar { width:100%; }
  .mobile-nav-toggle { display:block; }
  .main-nav { display:none; width:100%; flex-direction:column; gap:2px; order:3; padding-top:10px; border-top:1px solid var(--border); margin-top:10px; }
  .main-nav.open { display:flex; }
  .site-header .inner { flex-wrap:wrap; }
}