@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

/* ============ THEME TOKENS ============ */
:root{
  --blue:#0B5EA8;
  --blue-strong:#084B89;
  --blue-soft:#EAF4FF;
  --radius:14px;
}
html[data-theme="light"]{
  --ink:#F4F2EE;
  --bg-soft:#E9E3DD;
  --panel:#FFFDFB;
  --panel-2:#F1F1F1;
  --paper:#1B2432;
  --paper-dim:#586778;
  --line:#D8DEE7;
  --shadow:rgba(17,29,42,0.08);
}
html[data-theme="dark"]{
  --ink:#0F1724;
  --bg-soft:#152334;
  --panel:#182B3C;
  --panel-2:#1E354D;
  --paper:#F5F8FC;
  --paper-dim:#C7D5E8;
  --line:#2E425D;
  --shadow:rgba(0,0,0,0.36);
}

*{box-sizing:border-box; margin:0; padding:0;}
html{scroll-behavior:smooth;}
body{
  background:linear-gradient(180deg, var(--ink) 0%, var(--bg-soft) 100%);
  color:var(--paper);
  font-family:'Inter', sans-serif;
  line-height:1.6;
  font-size:16px;
  transition:background .25s ease, color .25s ease;
}
h1,h2,h3,h4{
  font-family:'Inter', sans-serif;
  font-weight:600;
  letter-spacing:-0.01em;
  color:var(--paper);
}
.mono{font-family:'Inter', sans-serif;}
a{color:var(--blue); text-decoration:none;}
a:hover{text-decoration:underline;}
a:focus-visible, button:focus-visible{outline:2px solid var(--blue); outline-offset:3px;}
img{max-width:100%; display:block;}
ul{list-style:none;}
.container{max-width:1080px; margin:0 auto; padding:0 2rem;}

/* ============ TOP NAV ============ */
header.topnav{
  position:sticky; top:0; z-index:100;
  background:var(--ink);
  border-bottom:1px solid var(--line);
}
.nav-inner{
  max-width:1080px; margin:0 auto; padding:0 2rem;
  display:flex; align-items:center; justify-content:space-between;
  gap:1.25rem; height:68px;
}
.nav-name{
  display:flex; align-items:flex-end; gap:0.22em;
  font-family:'Inter', sans-serif; font-weight:800; color:var(--paper);
  letter-spacing:0.01em; line-height:0.9; margin-right:2rem; white-space:nowrap;
  font-size:1.04rem; text-transform:uppercase;
}
.nav-name .brand-main,
.nav-name .brand-last{
  display:inline-block;
  font-size:1em;
}
.nav-name .brand-main { color:var(--paper); }
.nav-name .brand-last { color:var(--paper); }
.accent-letter{color:var(--blue); font-weight:900; font-size:1.08em;}
.nav-links{display:flex; align-items:center; gap:1.3rem; flex:1; justify-content:center;}
.nav-links a{color:var(--paper-dim); font-size:0.92rem; text-transform:uppercase; letter-spacing:0.04em; transition:color .15s;}
.nav-links a:hover{color:var(--blue); text-decoration:none;}
.theme-toggle{
  background:var(--panel-2); border:1px solid var(--line); color:var(--paper);
  width:38px; height:38px; border-radius:50%;
  display:flex; align-items:center; justify-content:center;
  cursor:pointer; font-size:1rem;
}
.nav-burger{display:none; background:none; border:none; color:var(--paper); font-size:1.5rem; cursor:pointer;}

@media (max-width:820px){
  .nav-links{
    position:fixed; top:68px; left:0; right:0;
    background:var(--ink); border-bottom:1px solid var(--line);
    flex-direction:column; align-items:flex-start; gap:0; padding:0.5rem 0;
    transform:translateY(-130%); transition:transform .25s ease; z-index:99;
  }
  .nav-links.open{transform:translateY(0);}
  .nav-links a{padding:0.9rem 2rem; width:100%;}
  .nav-burger{display:block;}
}

/* ============ SECTIONS ============ */
main section{
  padding:5rem 0;
  scroll-margin-top:80px;
}
main section + section{border-top:0;}
.eyebrow{display:none;} /* deprecated, kept out of layout */
.section-head h2{font-size:1.9rem;}
.section-head p.sub{color:var(--paper-dim); margin-top:0.5rem; font-size:1rem; max-width:56ch;}

/* ============ HERO ============ */
.hero{padding-top:3rem; padding-bottom:4rem; text-align:left;}
.hero h1{
  font-size:clamp(2.2rem, 3.2vw, 3.2rem);
  line-height:0.96;
  max-width:17ch;
  letter-spacing:0.02em;
  margin-top:0.2rem;
  text-transform:none;
  font-weight:800;
}
.hero .role{color:var(--blue); font-size:1.12rem; font-weight:600; margin-top:1rem;}
.hero p.lede{margin-top:1.1rem; max-width:760px; color:var(--paper-dim); font-size:1.08rem; line-height:1.7;}
.hero-actions{display:flex; gap:1rem; margin-top:1.8rem; flex-wrap:wrap;}
.btn{
  display:inline-block; padding:0.8rem 1.5rem; border-radius:var(--radius);
  font-size:0.92rem; font-weight:600; border:1px solid var(--line);
  transition:all .18s ease;
}
.btn-primary{background:linear-gradient(135deg, var(--blue-strong), var(--blue)); color:#fff; border-color:var(--blue); box-shadow:0 12px 24px rgba(11,94,168,0.18);}
.btn-primary:hover{opacity:0.98; text-decoration:none; transform:translateY(-1px);}
.btn-secondary{background:rgba(255,255,255,0.45); color:var(--paper); }
.btn-secondary:hover{border-color:var(--blue); color:var(--blue); text-decoration:none; transform:translateY(-1px);}
.hero-stats{display:flex; gap:1rem; margin-top:2.2rem; flex-wrap:wrap;}
.hero-stats div{
  border:1px solid var(--line);
  background:var(--panel);
  border-radius:12px;
  padding:0.9rem 1.15rem;
  min-width:145px;
  box-shadow:0 4px 14px rgba(15,23,42,0.04);
}
.hero-stats .num{font-family:'Inter', sans-serif; font-size:1.6rem; font-weight:700; line-height:1.1;}
.hero-stats .lbl{font-size:0.78rem; color:var(--paper-dim); margin-top:0.15rem; line-height:1.4;}

/* ============ SKILLS ============ */
.skill-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:1rem; margin-top:2.2rem;}
.skill-cat{background:var(--panel); border:1px solid var(--line); border-radius:14px; padding:1.2rem; box-shadow:0 6px 20px var(--shadow);}
.skill-cat h4{font-size:0.9rem; color:var(--paper); font-weight:700;}
.skill-chips{display:flex; flex-wrap:wrap; gap:0.45rem; margin-top:0.9rem;}
.chip{font-size:0.78rem; background:var(--panel-2); border:1px solid var(--line); padding:0.32rem 0.65rem; border-radius:8px; color:var(--paper-dim);}

/* ============ EXPERIENCE TIMELINE ============ */
.timeline{position:relative; margin-top:2.2rem;}
.timeline::before{content:""; position:absolute; left:7px; top:10px; bottom:10px; width:2px; background:var(--line);}
.tl-item{position:relative; padding-left:2.4rem; padding-bottom:2.4rem;}
.tl-item:last-child{padding-bottom:0;}
.tl-item::before{content:""; position:absolute; left:1px; top:6px; width:13px; height:13px; border-radius:50%; background:var(--blue); border:3px solid var(--ink); box-shadow:0 0 0 1px var(--blue);}
.tl-item h3{font-size:1.05rem;}
.tl-item .tl-org{color:var(--blue); font-size:0.92rem; margin-top:0.15rem;}
.tl-item .tl-when{font-family:'Inter', sans-serif; font-size:0.76rem; color:var(--paper-dim); margin-top:0.15rem;}
.tl-item ul{margin-top:0.7rem; padding-left:1.1rem; color:var(--paper-dim); font-size:0.94rem; list-style:disc;}
.tl-item li{margin-bottom:0.35rem;}

/* ============ EXPERIENCE CERTIFICATE ============ */
.experience-cert{display:inline-flex; align-items:center; gap:.45rem; margin-top:1rem; color:var(--blue); font-size:.82rem; font-weight:700;}
.experience-cert:hover{text-decoration:none; color:var(--blue);}
.cert-link-icon{width:24px; height:24px; border:1px solid var(--line); border-radius:50%; display:grid; place-items:center; font-size:.75rem;}

/* ============ RESEARCH INTERESTS ============ */
.research-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:1rem; margin-top:2.2rem;}
.research-card{border:1px solid var(--line); background:var(--panel); border-radius:14px; padding:1.35rem; box-shadow:0 8px 24px var(--shadow);}
.research-card span{font-size:.75rem; font-weight:700; color:var(--blue);}
.research-card h3{font-size:1rem; margin-top:.65rem;}
.research-card p{font-size:.86rem; color:var(--paper-dim); margin-top:.45rem;}

/* ============ EDUCATION ============ */
.edu-card{
  margin-top:2rem; border:1px solid var(--line); background:var(--panel);
  padding:1.6rem 1.8rem; border-radius:var(--radius);
  box-shadow:0 4px 14px rgba(15,23,42,0.03);
}
.edu-card h3{font-size:1.12rem; font-weight:700;}
.edu-card .edu-org{color:var(--blue); font-size:0.92rem; margin-top:0.2rem;}
.edu-card .edu-when{font-family:'Inter', sans-serif; font-size:0.76rem; color:var(--paper-dim); margin-top:0.2rem;}
.edu-card p{margin-top:0.7rem; color:var(--paper-dim); font-size:0.92rem;}

/* ============ THESIS ============ */
.thesis-box{
  margin-top:2.2rem; border:1px solid var(--line); background:var(--panel);
  padding:2.2rem; border-radius:var(--radius);
  box-shadow:0 4px 14px rgba(15,23,42,0.03);
}
.thesis-box h3{font-size:clamp(1.5rem, 2vw, 2.2rem); max-width:26ch; line-height:1.17;}
.thesis-box p{color:var(--paper-dim); margin-top:1rem; font-size:0.96rem; max-width:70ch; line-height:1.75;}
.tag-row{display:flex; flex-wrap:wrap; gap:0.5rem; margin-top:1.2rem;}
.tag{font-family:'Inter', sans-serif; font-size:0.72rem; color:var(--blue); border:1px solid var(--line); padding:0.28rem 0.7rem; border-radius:999px; background:rgba(31,138,112,0.06);}

/* ============ PROJECTS ============ */
.proj-grid{display:grid; grid-template-columns:repeat(3,1fr); gap:1.25rem; margin-top:2.2rem;}
.proj-card{border:1px solid var(--line); background:var(--panel); padding:0; border-radius:16px; overflow:hidden; display:flex; flex-direction:column; transition:border-color .2s, transform .2s, box-shadow .2s; box-shadow:0 8px 26px var(--shadow);}
.proj-card:hover{border-color:var(--blue); transform:translateY(-3px); box-shadow:0 14px 34px var(--shadow);}
.proj-cover{height:190px; background:var(--panel-2); overflow:hidden;}
.proj-cover img{width:100%; height:100%; object-fit:cover; transition:transform .25s ease;}
.proj-card:hover .proj-cover img{transform:scale(1.02);}
.proj-card.hide{display:none;}
.proj-card h4{font-size:1.02rem; padding:1.15rem 1.2rem 0;}
.proj-stack{padding:.35rem 1.2rem 0; color:var(--blue); font-size:.82rem; font-weight:600; line-height:1.5;}
.proj-card p{font-size:.86rem; color:var(--paper-dim); margin:.6rem 1.2rem 0; flex:1;}
.proj-card .proj-link{margin:1rem 1.2rem 1.2rem;}
.code-btn{display:inline-flex; align-items:center; gap:.4rem; font-size:.8rem; font-weight:600; border:1px solid var(--line); padding:.48rem .85rem; border-radius:99px; color:var(--paper);}
.code-btn:hover{border-color:var(--blue); color:var(--blue); text-decoration:none;}

/* ============ CERTIFICATES GALLERY (compact, filterable) ============ */
.cert-filters{display:flex; flex-wrap:wrap; gap:.55rem; margin-top:1.8rem;}
.cert-filter-btn{
  font-family:'Inter', sans-serif; font-size:.78rem; font-weight:600; color:var(--paper-dim);
  background:var(--panel); border:1px solid var(--line); padding:.45rem .9rem; border-radius:99px; cursor:pointer;
  transition:border-color .15s, color .15s, background .15s;
}
.cert-filter-btn:hover{color:var(--blue); border-color:var(--blue);}
.cert-filter-btn.active{background:var(--blue); border-color:var(--blue); color:#fff;}
.cert-grid{display:grid; grid-template-columns:repeat(4, 1fr); gap:1rem; margin-top:1.5rem;}
.cert-card{
  border:1px solid var(--line); background:var(--panel); border-radius:12px;
  overflow:hidden; cursor:pointer; transition:border-color .15s, transform .15s, box-shadow .15s;
  display:flex; flex-direction:column; box-shadow:0 4px 14px var(--shadow);
}
.cert-card.hide{display:none;}
.cert-card:hover{border-color:var(--blue); transform:translateY(-3px); box-shadow:0 10px 24px var(--shadow);}
.cert-thumb-wrap{height:118px; background:#F1F3F9; display:flex; align-items:center; justify-content:center; padding:.5rem; border-bottom:1px solid var(--line);}
.cert-thumb{width:100%; height:100%; object-fit:contain; display:block;}
.cert-card figcaption{padding:.65rem .75rem; font-size:.74rem; line-height:1.35; color:var(--paper); font-weight:600; min-height:2.5rem; display:flex; align-items:flex-start;}

/* Lightbox */
.lightbox{
  position:fixed; inset:0; background:rgba(5,8,11,0.88); z-index:200;
  display:none; align-items:center; justify-content:center; padding:2rem;
}
.lightbox.open{display:flex;}
.lightbox-inner{max-width:900px; width:100%; text-align:center;}
.lightbox-inner img{max-height:75vh; margin:0 auto; border-radius:var(--radius); background:#fff;}
.lightbox-cap{color:#E9E4D8; margin-top:1rem; font-size:0.95rem;}
.lightbox-cap a{margin-left:0.8rem;}
.lightbox-close{
  position:absolute; top:1.5rem; right:2rem; background:none; border:none;
  color:#E9E4D8; font-size:2rem; cursor:pointer; line-height:1;
}

/* ============ ACHIEVEMENTS ============ */
.ach-list{margin-top:2rem; display:flex; flex-direction:column; gap:0.9rem;}
.ach-list li{
  font-size:0.95rem; color:var(--paper); border-bottom:1px solid var(--line);
  padding-bottom:0.9rem; display:flex; justify-content:space-between; gap:1rem; flex-wrap:wrap;
}
.ach-list li:last-child{border-bottom:none;}
.ach-list .ach-when{font-family:'Inter', sans-serif; font-size:0.76rem; color:var(--paper-dim); white-space:nowrap;}

/* ============ CONTACT ============ */
.contact-section{padding:5rem 0 3.2rem; border-top:1px solid var(--line); background:linear-gradient(180deg, rgba(255,255,255,0.12), rgba(11,94,168,0.05));}
.contact-wrap{display:grid; grid-template-columns:1fr; gap:2rem;}
.contact-intro{text-align:center; max-width:760px; margin:0 auto;}
.contact-intro h2{font-size:2rem; letter-spacing:.04em; text-transform:uppercase;}
.contact-intro p{color:var(--paper-dim); margin-top:.7rem; font-size:1rem;}
.contact-pills{display:flex; flex-wrap:wrap; justify-content:center; gap:.9rem; margin-top:.5rem;}
.pill-card{
  display:inline-flex; align-items:center; gap:.6rem; padding:.85rem 1.5rem;
  border:1px solid var(--line); border-radius:99px; background:var(--panel); color:var(--paper);
  font-size:.92rem; font-weight:600; box-shadow:0 5px 18px var(--shadow); transition:transform .2s,border-color .2s;
}
.pill-card:hover{transform:translateY(-2px); border-color:var(--blue); text-decoration:none;}
.pill-static{cursor:default;}
.pill-static:hover{transform:none; border-color:var(--line);}
.pill-icon{width:26px; height:26px; display:grid; place-items:center; color:var(--blue); flex:0 0 26px;}
.pill-icon svg{width:22px; height:22px;}
.pill-icon-brand{
  background:#0A66C2; color:#fff; border-radius:6px; font-size:.85rem;
  font-family:Arial,sans-serif; font-weight:700; width:24px; height:24px;
}

/* ============ FOOTER ============ */
.site-footer{padding:3rem 1rem 2.2rem; text-align:center; border-top:1px solid var(--line);}
.footer-name{font-size:1.35rem; font-weight:700; color:var(--paper);}
.footer-role{color:var(--paper-dim); font-size:.88rem; margin-top:.3rem;}
.footer-socials{display:flex; justify-content:center; gap:1rem; margin-top:1.1rem;}
.footer-socials a{
  width:36px; height:36px; border-radius:50%; display:grid; place-items:center;
  color:var(--paper-dim); border:1px solid var(--line); transition:color .15s,border-color .15s;
}
.footer-socials a:hover{color:var(--blue); border-color:var(--blue); text-decoration:none;}
.footer-socials svg{width:18px; height:18px;}
.footer-copy{color:var(--paper-dim); font-size:.78rem; margin-top:1.2rem;}

/* ============ RESPONSIVE ============ */
@media (max-width:820px){
  .container{padding:0 1.3rem;}
  .nav-inner{padding:0 1.3rem;}
  main section{padding:3.2rem 0;}
  .hero h1{font-size:2.1rem;}
  .skill-grid{grid-template-columns:1fr 1fr;}
  .proj-grid{grid-template-columns:1fr 1fr;}
  .research-grid{grid-template-columns:1fr 1fr;}
  .cert-grid{grid-template-columns:repeat(3,1fr);}
  .pill-card{width:100%; justify-content:center;}
  .contact-pills{flex-direction:column; align-items:stretch;}
}
@media (max-width:480px){
  .research-grid{grid-template-columns:1fr;}
  .skill-grid,.proj-grid{grid-template-columns:1fr;}
  .cert-grid{grid-template-columns:1fr 1fr;}
  .hero-stats{gap:1.4rem;}
}