/* ============================================================
   Handityo Aulia Putra — personal site
   Palette: cool "signal" theme — cobalt→cyan accent, amber marks
   Type: Sora (display) · IBM Plex Sans (body) · IBM Plex Mono (labels)
   ============================================================ */
:root{
  --paper:#F6F8FC;
  --card:#FFFFFF;
  --ink:#0C1930;
  --muted:#4E5F7A;
  --line:#DCE5F1;
  --cobalt:#1A49CF;
  --cobalt-deep:#123795;
  --cyan:#2FB6C9;
  --sky:#EAF1FF;
  --amber:#EFA13A;
  --amber-deep:#A8650E;
  --grad:linear-gradient(90deg,var(--cobalt),var(--cyan));
  --radius:14px;
  /* fluid page gutter: ~22px on small phones -> 28px on wide screens */
  --gutter:clamp(1.375rem,1.1rem + 1.4vw,1.75rem);
  /* display-cutout insets; overridden below where the browser supports env() */
  --safe-l:0px;
  --safe-r:0px;
  --safe-b:0px;
  --shadow:0 1px 2px rgba(12,25,48,.05),0 8px 24px -12px rgba(12,25,48,.12);
  --shadow-hover:0 2px 4px rgba(12,25,48,.06),0 16px 36px -14px rgba(18,55,149,.22);
}
@supports (padding:env(safe-area-inset-left)){
  :root{
    --safe-l:env(safe-area-inset-left,0px);
    --safe-r:env(safe-area-inset-right,0px);
    --safe-b:env(safe-area-inset-bottom,0px);
  }
}
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;overflow-x:clip}
body{
  margin:0;
  font-family:'IBM Plex Sans','Noto Sans JP','Noto Sans KR',system-ui,-apple-system,'Segoe UI',sans-serif;
  font-size:16.5px;line-height:1.65;
  color:var(--ink);background:var(--paper);
  -webkit-font-smoothing:antialiased;
}
::selection{background:var(--cobalt);color:#fff}
img{max-width:100%;display:block}
/* never let a long DOI, URL or grant number push the page sideways */
body,h1,h2,h3,p,li,td,th{overflow-wrap:break-word}
/* anchors sit below the sticky header when jumped to */
section[id],h2[id],h3[id]{scroll-margin-top:84px}
a{color:var(--cobalt);text-decoration:none}
a:hover{color:var(--cobalt-deep)}
:focus-visible{outline:2px solid var(--cobalt);outline-offset:3px;border-radius:4px}
.skip{position:absolute;left:-999px;top:0;background:var(--ink);color:#fff;padding:.6rem 1rem;z-index:99;border-radius:0 0 8px 0}
.skip:focus{left:0}
.wrap{
  max-width:1060px;margin:0 auto;
  padding-inline:calc(var(--gutter) + var(--safe-l)) calc(var(--gutter) + var(--safe-r));
}

/* ---------- type ---------- */
h1,h2,h3{font-family:'Sora','Noto Sans JP','Noto Sans KR',sans-serif;line-height:1.15;margin:0 0 .5em;letter-spacing:-.02em}
h1{font-size:clamp(2.05rem,6vw,3.9rem);font-weight:700}
h2{font-size:clamp(1.55rem,3.4vw,2.15rem);font-weight:600}
h3{font-size:1.13rem;font-weight:600;letter-spacing:-.01em}
p{margin:0 0 1em}
.mono{font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace}
.eyebrow{
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.76rem;font-weight:500;
  text-transform:uppercase;letter-spacing:.16em;color:var(--cobalt);
  display:flex;align-items:center;gap:.65rem;margin:0 0 .9rem;
}
.eyebrow svg{flex:none;color:var(--cyan)}
.lead{font-size:1.13rem;color:var(--muted);max-width:56ch}

/* ---------- header / nav ---------- */
header.site{
  position:sticky;top:0;z-index:50;
  background:rgba(246,248,252,.85);backdrop-filter:blur(10px);
  border-bottom:1px solid var(--line);
}
.nav{display:flex;align-items:center;justify-content:space-between;gap:1rem;height:64px}
.brand{display:flex;align-items:center;gap:.6rem;font-family:'Sora','Noto Sans JP','Noto Sans KR',sans-serif;font-weight:600;font-size:1rem;color:var(--ink)}
.brand:hover{color:var(--ink)}
.brand .pulse{width:26px;height:26px;flex:none}
.nav-links{display:flex;align-items:center;gap:1.4rem;list-style:none;margin:0;padding:0}
.nav-links a{font-size:.94rem;font-weight:500;color:var(--muted);padding:.35rem 0;border-bottom:2px solid transparent}
.nav-links a:hover{color:var(--ink)}
.nav-links a[aria-current="page"]{color:var(--ink);border-bottom-color:var(--cobalt)}
.nav-links .cta{border:1.5px solid var(--cobalt);color:var(--cobalt);padding:.42rem 1rem;border-radius:999px;border-bottom:1.5px solid var(--cobalt)}
.nav-links .cta:hover{background:var(--cobalt);color:#fff}
.burger{display:none;background:none;border:1px solid var(--line);border-radius:8px;padding:.45rem .6rem;cursor:pointer;color:var(--ink)}

/* ---------- hero ---------- */
/* padding-block only - a `padding` shorthand here would cancel .wrap's gutter
   and leave the hero flush against the screen edge on narrow displays */
.hero{padding-block:4.2rem 3rem}
.hero-grid{display:grid;grid-template-columns:1fr auto;gap:2.5rem;align-items:center}
.hero h1 .accent{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}
.hero .roles{font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.85rem;color:var(--muted);margin:.4rem 0 1.2rem}
.hero .roles a{color:inherit;border-bottom:1px dotted var(--muted)}
.monogram{
  width:150px;height:150px;border-radius:50%;flex:none;
  display:flex;align-items:center;justify-content:center;
  font-family:'Sora','Noto Sans JP','Noto Sans KR',sans-serif;font-weight:700;font-size:2.5rem;color:var(--cobalt-deep);
  background:var(--card);position:relative;box-shadow:var(--shadow);
}
.monogram::before{
  content:"";position:absolute;inset:-5px;border-radius:50%;
  background:var(--grad);z-index:-1;
}
.monogram::after{
  content:"";position:absolute;inset:-2px;border-radius:50%;background:var(--paper);z-index:-1;
}
.btn-row{display:flex;flex-wrap:wrap;gap:.8rem;margin:1.6rem 0 0}
.btn{
  display:inline-flex;align-items:center;gap:.5rem;
  font-weight:600;font-size:.95rem;padding:.68rem 1.35rem;border-radius:999px;
  background:var(--cobalt);color:#fff;border:1.5px solid var(--cobalt);
  transition:transform .15s ease,box-shadow .15s ease,background .15s ease;
}
.btn:hover{background:var(--cobalt-deep);border-color:var(--cobalt-deep);color:#fff;transform:translateY(-1px);box-shadow:var(--shadow-hover)}
.btn.ghost{background:transparent;color:var(--cobalt)}
.btn.ghost:hover{background:var(--sky);color:var(--cobalt-deep)}

/* signature waveform */
.wave{margin:2.6rem 0 0;color:var(--cobalt)}
.wave svg{width:100%;height:70px;display:block;overflow:visible}
.wave .trace{
  fill:none;stroke:url(#waveGrad);stroke-width:2.5;stroke-linecap:round;stroke-linejoin:round;
}
.wave .peak{fill:var(--amber);opacity:0}
@media (prefers-reduced-motion:no-preference){
  .wave .trace{stroke-dasharray:1;stroke-dashoffset:1;animation:draw 2.2s ease-out .3s forwards}
  .wave .peak{animation:pop .5s ease-out 2.1s forwards}
  @keyframes draw{to{stroke-dashoffset:0}}
  @keyframes pop{from{opacity:0;transform:scale(.3);transform-origin:center}to{opacity:1;transform:scale(1)}}
}
@media (prefers-reduced-motion:reduce){
  .wave .peak{opacity:1}
}

/* hero stats */
.stats{display:flex;flex-wrap:wrap;gap:2.4rem;margin:1.9rem 0 0;padding:0;list-style:none}
.stats .num{font-family:'Sora','Noto Sans JP','Noto Sans KR',sans-serif;font-weight:700;font-size:1.55rem;color:var(--ink)}
.stats .lbl{font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.74rem;text-transform:uppercase;letter-spacing:.12em;color:var(--muted)}

.tagline{font-family:'Sora','Noto Sans JP','Noto Sans KR',sans-serif;font-weight:600;font-size:clamp(1.18rem,2.6vw,1.55rem);letter-spacing:-.015em;margin:.7rem 0 1rem}
.tagline .accent{background:var(--grad);-webkit-background-clip:text;background-clip:text;color:transparent}

/* ---------- sections ---------- */
section.block{padding:3.4rem 0;border-top:1px solid var(--line)}
.sec-head{margin-bottom:2rem;max-width:62ch}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:1.4rem}
.grid-2>*,.grid-3>*,.proj-grid>*,.about-grid>*,.hero-grid>*{min-width:0}
.about-grid{display:grid;grid-template-columns:1.55fr 1fr;gap:2.2rem;align-items:start}
.facts{list-style:none;margin:0;padding:0}
.facts li{display:flex;flex-direction:column;gap:.1rem;padding:.7rem 0;border-bottom:1px solid var(--line)}
.facts li:last-child{border-bottom:none}
.facts .k{font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.72rem;text-transform:uppercase;letter-spacing:.13em;color:var(--muted)}
.facts .v{font-size:.95rem;font-weight:500}
.grid-3{display:grid;grid-template-columns:repeat(3,1fr);gap:1.4rem}

.card{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:1.5rem 1.6rem;box-shadow:var(--shadow);
  transition:transform .18s ease,box-shadow .18s ease;
}
.card:hover{transform:translateY(-2px);box-shadow:var(--shadow-hover)}
.card h3{margin-top:.15rem}
.card p{color:var(--muted);font-size:.96rem;margin-bottom:0}
.card .chan{
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.72rem;letter-spacing:.14em;
  text-transform:uppercase;color:var(--cyan);margin-bottom:.55rem;
}

/* tag chips */
.tags{display:flex;flex-wrap:wrap;gap:.5rem;margin:.9rem 0 0;padding:0;list-style:none}
.tag{
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.78rem;color:var(--cobalt-deep);
  background:var(--sky);border:1px solid #CDDCFB;border-radius:999px;padding:.22rem .7rem;
  max-width:100%;overflow-wrap:anywhere;
}

/* ---------- timeline ---------- */
.timeline{list-style:none;margin:0;padding:0;position:relative}
.timeline::before{
  content:"";position:absolute;left:7px;top:6px;bottom:6px;width:2px;
  background:linear-gradient(180deg,var(--cobalt),var(--cyan));border-radius:2px;opacity:.4;
}
.timeline li{position:relative;padding:0 0 1.9rem 2.2rem}
.timeline li:last-child{padding-bottom:0}
.timeline li::before{
  content:"";position:absolute;left:0;top:7px;width:16px;height:16px;border-radius:50%;
  background:var(--card);border:3px solid var(--cobalt);
}
.timeline .when{font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.78rem;letter-spacing:.08em;color:var(--muted);text-transform:uppercase}
.timeline h3{margin:.2rem 0 .25rem}
.timeline .org{font-weight:500;color:var(--cobalt-deep)}
.timeline p{color:var(--muted);font-size:.95rem;margin:.35rem 0 0;max-width:64ch}

/* ---------- skills ---------- */
.skill-group h3{display:flex;align-items:center;gap:.55rem}
.skill-group h3::before{content:"";width:9px;height:9px;border-radius:50%;background:var(--grad)}

/* ---------- publications ---------- */
.pub-year{margin:2.6rem 0 1.1rem;display:flex;align-items:center;gap:1rem}
.pub-year .yr{font-family:'Sora','Noto Sans JP','Noto Sans KR',sans-serif;font-weight:700;font-size:1.35rem}
.pub-year::after{content:"";flex:1;height:1px;background:var(--line)}
.pub{
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  padding:1.35rem 1.5rem;margin-bottom:1rem;box-shadow:var(--shadow);
  transition:box-shadow .18s ease,transform .18s ease;
}
.pub:hover{box-shadow:var(--shadow-hover);transform:translateY(-2px)}
.pub h3{font-size:1.06rem;margin:0 0 .35rem;line-height:1.4}
.pub .authors{font-size:.93rem;color:var(--muted);margin:0 0 .25rem}
.pub .authors strong{color:var(--ink);font-weight:600}
.pub .venue{font-size:.93rem;color:var(--muted);font-style:italic;margin:0 0 .8rem}
.pub .venue .mono{font-style:normal;font-size:.82rem}
.pub-links{display:flex;flex-wrap:wrap;gap:.55rem}
.pill{
  display:inline-flex;align-items:center;gap:.35rem;
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.78rem;font-weight:500;
  border:1px solid var(--line);border-radius:999px;padding:.26rem .75rem;color:var(--cobalt-deep);
  background:#FBFCFE;
  max-width:100%;overflow-wrap:anywhere;
}
.pill:hover{border-color:var(--cobalt);background:var(--sky)}
.badge{
  display:inline-block;font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.7rem;font-weight:500;
  letter-spacing:.08em;text-transform:uppercase;border-radius:6px;padding:.18rem .55rem;
  background:#FDF3E3;color:var(--amber-deep);border:1px solid #F3D9AC;margin-left:.5rem;vertical-align:2px;
}
.badge.oa{background:#E7F6F1;color:#0E6E52;border-color:#BCE5D6}

/* ---------- projects ---------- */
.proj-grid{display:grid;grid-template-columns:1fr 1fr;gap:1.4rem}
.proj .links{margin-top:1rem;display:flex;flex-wrap:wrap;gap:.55rem}

/* ---------- contact ---------- */
.contact-card{
  background:var(--ink);color:#DCE5F1;border-radius:20px;padding:2.6rem 2.4rem;
  position:relative;overflow:hidden;
}
.contact-card::after{
  content:"";position:absolute;right:-60px;top:-60px;width:260px;height:260px;border-radius:50%;
  background:var(--grad);opacity:.22;filter:blur(6px);
}
.contact-card h2{color:#fff}
.contact-card p{color:#AFC0D8;max-width:52ch}
.contact-links{display:flex;flex-wrap:wrap;gap:.7rem;margin-top:1.4rem;position:relative;z-index:1}
.contact-links a{
  display:inline-flex;align-items:center;gap:.45rem;
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.84rem;color:#EAF1FF;
  border:1px solid #33507E;border-radius:999px;padding:.45rem 1rem;background:rgba(255,255,255,.04);
}
.contact-links a:hover{border-color:var(--cyan);color:#fff;background:rgba(47,182,201,.12)}

/* ---------- todo markers (edit-me placeholders) ---------- */
.todo{
  outline:2px dashed var(--amber);outline-offset:2px;border-radius:6px;
  background:#FDF6E9;color:var(--amber-deep);padding:0 .3rem;
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.85em;
}

/* ---------- language switcher ---------- */
.nav-links{margin-left:auto}
.langsw{display:flex;align-items:center;gap:.28rem;flex:none}
.langsw a{
  display:inline-flex;align-items:center;min-height:32px;
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;
  font-size:.74rem;font-weight:500;line-height:1;white-space:nowrap;
  color:var(--muted);border:1px solid transparent;border-radius:999px;
  padding:.34rem .58rem;
  transition:background .15s ease,color .15s ease,border-color .15s ease;
}
.langsw a:hover{color:var(--ink);background:var(--sky)}
.langsw a[aria-current="true"]{color:#fff;background:var(--cobalt);border-color:var(--cobalt)}

/* ---------- section jump nav ---------- */
.jumpnav{
  display:flex;flex-wrap:wrap;align-items:center;gap:.55rem;
  margin:2.4rem 0 .4rem;padding:.9rem 1.1rem;
  background:var(--card);border:1px solid var(--line);border-radius:var(--radius);
  box-shadow:var(--shadow);
}
.jumpnav .lbl{
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.72rem;font-weight:500;
  text-transform:uppercase;letter-spacing:.14em;color:var(--muted);margin-right:.2rem;
}
.jumpnav a{
  font-family:'IBM Plex Mono','Noto Sans JP','Noto Sans KR',monospace;font-size:.78rem;font-weight:500;
  color:var(--cobalt-deep);background:#FBFCFE;
  border:1px solid var(--line);border-radius:999px;padding:.28rem .8rem;
  transition:background .15s ease,border-color .15s ease,color .15s ease;
}
.jumpnav a:hover{border-color:var(--cobalt);background:var(--sky)}
.jumpnav a[aria-current="true"]{background:var(--cobalt);border-color:var(--cobalt);color:#fff}
.pub-year{scroll-margin-top:92px}

/* ---------- back to top ---------- */
.totop{
  position:fixed;z-index:60;
  right:calc(16px + var(--safe-r));bottom:calc(16px + var(--safe-b));
  width:44px;height:44px;padding:0;border-radius:50%;
  display:flex;align-items:center;justify-content:center;
  background:var(--card);color:var(--cobalt);
  border:1px solid var(--line);box-shadow:var(--shadow-hover);cursor:pointer;
  opacity:0;visibility:hidden;transform:translateY(8px);
  transition:opacity .25s ease,transform .25s ease,visibility .25s ease,background .15s ease,color .15s ease,border-color .15s ease;
}
.totop.show{opacity:1;visibility:visible;transform:none}
.totop:hover{background:var(--cobalt);color:#fff;border-color:var(--cobalt)}
@media (prefers-reduced-motion:reduce){
  .totop{transition:opacity .01s linear,visibility .01s linear;transform:none}
}

/* ---------- footer ---------- */
footer.site{border-top:1px solid var(--line);padding:2rem 0 calc(2.4rem + var(--safe-b));margin-top:3.5rem}
footer .row{display:flex;flex-wrap:wrap;justify-content:space-between;gap:1rem;align-items:center}
footer p{margin:0;font-size:.86rem;color:var(--muted)}
footer .mini{display:flex;gap:1.1rem}
footer .mini a{font-size:.86rem;color:var(--muted)}
footer .mini a:hover{color:var(--cobalt)}

/* ---------- reveal on scroll ---------- */
.reveal{opacity:0;transform:translateY(14px);transition:opacity .55s ease,transform .55s ease}
.reveal.in{opacity:1;transform:none}
@media (prefers-reduced-motion:reduce){
  .reveal{opacity:1;transform:none;transition:none}
  html{scroll-behavior:auto}
}

/* ---------- responsive ----------
   Vertical rhythm and card padding step down alongside the fluid --gutter, so
   narrow screens gain edge breathing room without losing text width. */
@media (max-width:880px){
  .grid-3{grid-template-columns:1fr 1fr}
}
@media (max-width:900px){
  .burger{display:block}
  .nav-links{
    display:none;position:absolute;left:0;right:0;top:64px;
    background:var(--card);border-bottom:1px solid var(--line);
    flex-direction:column;align-items:flex-start;gap:1rem;
    padding-block:1rem 1.3rem;
    padding-inline:calc(var(--gutter) + var(--safe-l)) calc(var(--gutter) + var(--safe-r));
    box-shadow:var(--shadow);
  }
  .nav-links.open{display:flex}
  /* keep the switcher visible outside the collapsed menu: brand · langsw · burger */
  .langsw{order:2}
  .burger{order:3}
}
/* the fixed back-to-top button floats bottom-right; give the footer row room
   so it never lands on top of the footer links */
@media (max-width:1180px){
  footer.site{padding-bottom:calc(4.4rem + var(--safe-b))}
}
@media (max-width:760px){
  .hero-grid{grid-template-columns:1fr}
  .monogram{order:-1;width:110px;height:110px;font-size:1.9rem}
  .grid-2,.grid-3,.proj-grid,.about-grid{grid-template-columns:1fr}
  .stats{gap:1.6rem}

  .hero{padding-block:2.9rem 2.2rem}
  section.block{padding:2.7rem 0}
  .sec-head{margin-bottom:1.5rem}
  .wave{margin-top:2rem}
  .wave svg{height:58px}
  footer.site{margin-top:2.6rem}
}
@media (max-width:560px){
  .brand .brand-name{display:none}
  .langsw a{padding:.3rem .45rem;font-size:.72rem}

  .card{padding:1.25rem 1.15rem}
  .pub{padding:1.2rem 1.15rem}
  .contact-card{padding:1.9rem 1.35rem;border-radius:16px}
  .jumpnav{padding:.8rem .9rem;gap:.45rem}
  .stats{gap:1.1rem 1.9rem}
  .timeline li{padding-left:1.9rem}
  .totop{width:40px;height:40px}
}
@media (max-width:400px){
  .nav{gap:.55rem}
  .langsw{gap:.15rem}
  .langsw a{padding:.3rem .34rem}
  .hero{padding-block:2.3rem 1.9rem}
  .card,.pub{padding:1.1rem 1rem}
  .contact-card{padding:1.6rem 1.15rem}
  .btn{padding:.62rem 1.05rem;font-size:.9rem}
  .btn-row{gap:.6rem}
  .stats{gap:.95rem 1.5rem}
  .wave svg{height:48px}
}