/* =========================================================
   AMAL SEBASTIAN — AI/ML PORTFOLIO
   Design tokens
   ========================================================= */
:root{
  --paper: #EEF0F4;
  --paper-dim: #E3E6EE;
  --ink: #14161F;
  --ink-soft: #4A4E5E;
  --line: #D3D7E3;
  --cobalt: #2A3EFF;
  --cobalt-dim: #E8EAFF;
  --coral: #FF5D5D;
  --node: #14161F;

  --font-display: "Fraunces", Georgia, serif;
  --font-body: "Inter", -apple-system, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;

  --radius: 4px;
  --max-w: 1160px;
}

*{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  background:var(--paper);
  color:var(--ink);
  font-family:var(--font-body);
  line-height:1.6;
  -webkit-font-smoothing:antialiased;
}
img{max-width:100%;display:block;}
a{color:inherit;text-decoration:none;}
ul{list-style:none;margin:0;padding:0;}
h1,h2,h3,h4{font-family:var(--font-display);font-weight:600;line-height:1.1;margin:0 0 .5em;}
p{margin:0 0 1em;}

@media (prefers-reduced-motion: reduce){
  *{animation-duration:.001ms !important; animation-iteration-count:1 !important; transition-duration:.001ms !important; scroll-behavior:auto !important;}
}

/* ---------- layout helpers ---------- */
.wrap{max-width:var(--max-w);margin:0 auto;padding:0 28px;}
.eyebrow{
  font-family:var(--font-mono);
  font-size:.72rem;
  letter-spacing:.12em;
  text-transform:uppercase;
  color:var(--cobalt);
  display:inline-flex;
  align-items:center;
  gap:8px;
  margin-bottom:14px;
}
.eyebrow::before{content:"";width:7px;height:7px;background:var(--coral);border-radius:50%;display:inline-block;}
.section{padding:88px 0;}
.section-tight{padding:56px 0;}
.section-head{max-width:640px;margin-bottom:48px;}
.section-head h2{font-size:clamp(1.7rem,3vw,2.4rem);}
.section-head p{color:var(--ink-soft);font-size:1.05rem;}
.divider{height:1px;background:var(--line);border:0;margin:0;}

/* ---------- nav ---------- */
.site-header{
  position:sticky;top:0;z-index:50;
  background:rgba(238,240,244,.88);
  backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.nav{
  display:flex;align-items:center;justify-content:space-between;
  padding:18px 28px;max-width:var(--max-w);margin:0 auto;
}
.logo{
  font-family:var(--font-mono);font-weight:700;font-size:1rem;
  display:flex;align-items:center;gap:10px;
}
.logo .dot-mark{width:10px;height:10px;background:var(--cobalt);display:inline-block;border-radius:2px;transform:rotate(45deg);}
.nav-links{display:flex;gap:2px;align-items:center;}
.nav-links a{
  font-family:var(--font-mono);font-size:.82rem;padding:8px 12px;
  border-radius:var(--radius);color:var(--ink-soft);
  transition:color .15s, background .15s;
}
.nav-links a:hover, .nav-links a:focus-visible{color:var(--ink);background:var(--paper-dim);}
.nav-links a.active{color:var(--cobalt);}
.nav-toggle{display:none;background:none;border:1px solid var(--line);border-radius:var(--radius);padding:8px 10px;font-family:var(--font-mono);cursor:pointer;}

@media (max-width: 860px){
  .nav-toggle{display:block;}
  .nav-links{
    position:fixed;inset:64px 0 0 0;background:var(--paper);
    flex-direction:column;align-items:flex-start;padding:20px 28px;
    gap:4px;display:none;border-top:1px solid var(--line);
    overflow-y:auto;
  }
  .nav-links.open{display:flex;}
  .nav-links a{width:100%;padding:14px 4px;border-bottom:1px solid var(--line);border-radius:0;}
}

/* ---------- buttons ---------- */
.btn{
  display:inline-flex;align-items:center;gap:8px;
  font-family:var(--font-mono);font-size:.85rem;
  padding:12px 20px;border-radius:var(--radius);
  border:1px solid var(--ink);cursor:pointer;
  transition:transform .15s, background .15s, color .15s;
}
.btn-primary{background:var(--ink);color:var(--paper);}
.btn-primary:hover{background:var(--cobalt);border-color:var(--cobalt);transform:translateY(-2px);}
.btn-ghost{background:transparent;color:var(--ink);}
.btn-ghost:hover{background:var(--ink);color:var(--paper);transform:translateY(-2px);}
.btn:disabled, .btn.disabled{opacity:.4;cursor:not-allowed;transform:none !important;}

/* ---------- hero / node canvas ---------- */
.hero{position:relative;overflow:hidden;border-bottom:1px solid var(--line);}
#node-canvas{position:absolute;inset:0;width:100%;height:100%;opacity:.55;}
.hero-inner{position:relative;z-index:2;padding:120px 0 90px;}
.hero h1{font-size:clamp(2.4rem,6vw,4.6rem);max-width:900px;}
.hero .lede{font-size:1.15rem;color:var(--ink-soft);max-width:540px;}
.hero-cta{display:flex;gap:14px;margin-top:32px;flex-wrap:wrap;}
.hero-tags{display:flex;gap:10px;flex-wrap:wrap;margin-top:40px;}
.chip{
  font-family:var(--font-mono);font-size:.72rem;letter-spacing:.03em;
  padding:6px 12px;border:1px solid var(--line);border-radius:20px;
  background:var(--paper);color:var(--ink-soft);
}

/* ---------- cards / grids ---------- */
.grid{display:grid;gap:24px;}
.grid-2{grid-template-columns:repeat(2,1fr);}
.grid-3{grid-template-columns:repeat(3,1fr);}
.grid-4{grid-template-columns:repeat(4,1fr);}
@media (max-width:900px){.grid-2,.grid-3,.grid-4{grid-template-columns:1fr;}}

.card{
  background:#fff;border:1px solid var(--line);border-radius:var(--radius);
  padding:26px;transition:transform .18s, box-shadow .18s;
}
.card:hover{transform:translateY(-3px);box-shadow:0 12px 28px -18px rgba(20,22,31,.35);}

.card-num{font-family:var(--font-mono);font-size:.75rem;color:var(--coral);}

/* ---------- footer ---------- */
.site-footer{border-top:1px solid var(--line);background:var(--paper-dim);padding:52px 0 28px;margin-top:60px;}
.footer-grid{display:grid;grid-template-columns:1.4fr 1fr 1fr 1fr;gap:32px;margin-bottom:36px;}
@media (max-width:800px){.footer-grid{grid-template-columns:1fr 1fr;}}
.footer-grid h4{font-family:var(--font-mono);font-size:.78rem;text-transform:uppercase;letter-spacing:.08em;color:var(--ink-soft);margin-bottom:14px;}
.footer-grid a{display:block;padding:4px 0;color:var(--ink);font-size:.92rem;}
.footer-grid a:hover{color:var(--cobalt);}
.footer-bottom{
  display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;
  font-family:var(--font-mono);font-size:.75rem;color:var(--ink-soft);
  border-top:1px solid var(--line);padding-top:20px;
}

/* ---------- page hero (non-home) ---------- */
.page-hero{padding:64px 0 40px;border-bottom:1px solid var(--line);}
.page-hero h1{font-size:clamp(2rem,4vw,3rem);}

/* ---------- skills ---------- */
.skill-cat h3{font-family:var(--font-mono);font-size:.85rem;text-transform:uppercase;letter-spacing:.06em;color:var(--coral);margin-bottom:16px;}
.skill-list{display:flex;flex-wrap:wrap;gap:10px;margin-bottom:40px;}
.skill-pill{
  font-family:var(--font-mono);font-size:.82rem;padding:9px 14px;
  border:1px solid var(--line);border-radius:var(--radius);background:#fff;
}

/* ---------- timeline (academics/experience) ---------- */
.timeline{border-left:2px solid var(--line);padding-left:28px;position:relative;}
.timeline-item{position:relative;padding-bottom:36px;}
.timeline-item:last-child{padding-bottom:0;}
.timeline-item::before{
  content:"";position:absolute;left:-33px;top:4px;width:10px;height:10px;
  background:var(--cobalt);border-radius:50%;border:3px solid var(--paper);
}
.timeline-item .meta{font-family:var(--font-mono);font-size:.75rem;color:var(--ink-soft);margin-bottom:4px;}
.timeline-item h3{font-size:1.15rem;margin-bottom:4px;}

/* ---------- achievements ---------- */
.badge-card{display:flex;gap:16px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:20px;}
.badge-thumb{
  width:64px;height:64px;flex:none;border-radius:var(--radius);
  background:var(--cobalt-dim);display:flex;align-items:center;justify-content:center;
  font-family:var(--font-mono);font-weight:700;color:var(--cobalt);
  overflow:hidden;
}
.badge-thumb img{width:100%;height:100%;object-fit:cover;}

/* ---------- projects ---------- */
.filter-bar{display:flex;gap:12px;flex-wrap:wrap;margin-bottom:32px;align-items:center;}
.filter-bar input[type="search"]{
  flex:1;min-width:200px;padding:12px 14px;border:1px solid var(--line);
  border-radius:var(--radius);font-family:var(--font-body);background:#fff;
}
.filter-chip{
  font-family:var(--font-mono);font-size:.75rem;padding:8px 14px;border:1px solid var(--line);
  border-radius:20px;background:#fff;cursor:pointer;transition:.15s;
}
.filter-chip.active{background:var(--ink);color:var(--paper);border-color:var(--ink);}
.project-card{display:flex;flex-direction:column;height:100%;}
.project-thumb{width:100%;aspect-ratio:16/9;object-fit:cover;border-radius:var(--radius);margin-bottom:16px;background:var(--paper-dim);}
.project-card h3{font-size:1.2rem;margin-bottom:6px;}
.project-tags{display:flex;gap:6px;flex-wrap:wrap;margin:10px 0 14px;}
.tag{font-family:var(--font-mono);font-size:.68rem;padding:4px 9px;border-radius:20px;background:var(--cobalt-dim);color:var(--cobalt);}
.tag.status-progress{background:#FFF0E0;color:#B5641A;}
.tag.status-done{background:#E4F6EA;color:#1F8A4C;}
.project-links{display:flex;gap:10px;margin-top:auto;padding-top:14px;}
.project-links .btn{padding:9px 14px;font-size:.78rem;}
.no-results{display:none;color:var(--ink-soft);font-family:var(--font-mono);font-size:.85rem;padding:40px 0;text-align:center;}

/* ---------- research ---------- */
.research-card{display:grid;grid-template-columns:220px 1fr;gap:24px;background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;margin-bottom:24px;}
.research-card img{border-radius:var(--radius);aspect-ratio:4/3;object-fit:cover;background:var(--paper-dim);}
@media (max-width:700px){.research-card{grid-template-columns:1fr;}}

/* ---------- feedback ---------- */
.stat-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:20px;margin-bottom:48px;}
@media (max-width:700px){.stat-strip{grid-template-columns:1fr 1fr;}}
.stat-box{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:22px;text-align:center;}
.stat-box .num{font-family:var(--font-display);font-size:2.1rem;color:var(--cobalt);}
.stat-box .label{font-family:var(--font-mono);font-size:.7rem;color:var(--ink-soft);text-transform:uppercase;letter-spacing:.06em;}
.testimonial{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;}
.testimonial-head{display:flex;gap:14px;align-items:center;margin-bottom:12px;}
.testimonial-avatar{width:48px;height:48px;border-radius:50%;background:var(--paper-dim);object-fit:cover;flex:none;}
.testimonial-name{font-weight:600;font-size:.95rem;}
.testimonial-role{font-family:var(--font-mono);font-size:.72rem;color:var(--ink-soft);}
.stars{color:var(--coral);font-size:.85rem;letter-spacing:2px;margin-bottom:8px;}
.placeholder-note{
  border:1px dashed var(--line);border-radius:var(--radius);padding:16px 20px;
  font-family:var(--font-mono);font-size:.78rem;color:var(--ink-soft);background:var(--paper-dim);
  margin-bottom:32px;
}

/* ---------- contact ---------- */
.contact-grid{display:grid;grid-template-columns:1fr 1fr;gap:48px;}
@media (max-width:800px){.contact-grid{grid-template-columns:1fr;}}
.form-field{margin-bottom:18px;}
.form-field label{display:block;font-family:var(--font-mono);font-size:.75rem;text-transform:uppercase;letter-spacing:.05em;margin-bottom:6px;color:var(--ink-soft);}
.form-field input, .form-field textarea{
  width:100%;padding:13px 14px;border:1px solid var(--line);border-radius:var(--radius);
  font-family:var(--font-body);font-size:.95rem;background:#fff;
}
.form-field input:focus, .form-field textarea:focus{outline:2px solid var(--cobalt);outline-offset:1px;}
.form-status{font-family:var(--font-mono);font-size:.82rem;margin-top:14px;min-height:20px;}
.form-status.ok{color:#1F8A4C;}
.form-status.err{color:var(--coral);}

/* ---------- blog ---------- */
.blog-card h3{font-size:1.15rem;margin-bottom:8px;}
.blog-meta{font-family:var(--font-mono);font-size:.72rem;color:var(--ink-soft);margin-bottom:12px;}
.blog-excerpt{color:var(--ink-soft);font-size:.92rem;}

/* ---------- misc ---------- */
:focus-visible{outline:2px solid var(--cobalt);outline-offset:2px;}
.reveal{opacity:0;transform:translateY(18px);transition:opacity .6s ease, transform .6s ease;}
.reveal.in{opacity:1;transform:translateY(0);}