/* ==========================================================================
   REDESIGN — "SIGNAL SHEET": engineering-drawing / schematic identity.
   Static HTML/CSS/JS only. Honors the hard contracts of the sandbox brief:
   flash-free persistent theme toggle, two keyboard-operable galleries,
   outbound links with target=_blank + rel, a11y, 320px+, images/ paths kept.
   ========================================================================== */
*{margin:0;padding:0;box-sizing:border-box}

:root{
  --font-disp:'Space Grotesk','Segoe UI',system-ui,sans-serif;
  --font-mono:'IBM Plex Mono','Fira Code',ui-monospace,Menlo,monospace;
  --font-px:'Silkscreen','IBM Plex Mono',monospace;
  --wrap:1180px;
  --rail:56px;
}
:root, :root[data-theme="light"]{
  color-scheme:light;
  --bg:#f1efe7; --bg2:#e8e5da; --panel:#faf9f3;
  --ink:#161a20; --mut:#5c6270;
  --line:rgba(22,26,32,.18); --line2:rgba(22,26,32,.5);
  --acc:#b45309; --acc-soft:rgba(180,83,9,.12);
  --ok:#15803d; --ok-soft:rgba(21,128,61,.14);
  --grid:rgba(22,26,32,.055);
  --shadow:0 14px 34px rgba(22,26,32,.10);
}
:root[data-theme="dark"]{
  color-scheme:dark;
  --bg:#0b0e13; --bg2:#0e1219; --panel:#12161f;
  --ink:#e6e9f0; --mut:#98a1b3;
  --line:rgba(230,233,240,.15); --line2:rgba(230,233,240,.38);
  --acc:#ffb454; --acc-soft:rgba(255,180,84,.13);
  --ok:#4ade80; --ok-soft:rgba(74,222,128,.14);
  --grid:rgba(230,233,240,.05);
  --shadow:0 14px 34px rgba(0,0,0,.45);
}

html{scroll-behavior:smooth}
body{
  font-family:var(--font-disp);
  background:var(--bg);
  background-image:linear-gradient(var(--grid) 1px,transparent 1px),linear-gradient(90deg,var(--grid) 1px,transparent 1px);
  background-size:34px 34px;
  color:var(--ink);
  font-size:16px; line-height:1.6;
  overflow-x:clip;
  transition:background-color .25s ease,color .25s ease;
}
img{display:block;max-width:100%}
a{color:var(--acc)}
::selection{background:var(--acc);color:var(--bg)}
:focus-visible{outline:2px solid var(--acc);outline-offset:3px;border-radius:2px}
.mono{font-family:var(--font-mono)}
.visually-hidden{position:absolute;width:1px;height:1px;margin:-1px;padding:0;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.skip-link{position:absolute;left:1rem;top:-4rem;z-index:300;background:var(--ink);color:var(--bg);padding:.6rem 1rem;font-family:var(--font-mono);font-size:.8rem;text-decoration:none;transition:top .2s}
.skip-link:focus{top:1rem}

/* ---------- scroll reveal ---------- */
.rv{opacity:0;transform:translateY(20px);transition:opacity .6s ease,transform .6s ease}
.rv.in{opacity:1;transform:none}

/* ---------- left rail (scroll trace) ---------- */
.rail{position:fixed;top:0;bottom:0;left:0;width:var(--rail);border-right:1px solid var(--line);display:none;flex-direction:column;align-items:center;justify-content:space-between;padding:1.1rem 0;background:var(--bg);z-index:60}
.rail-track{position:relative;width:2px;flex:1;margin:1rem 0;background:var(--line)}
.rail-fill{position:absolute;inset:0;background:var(--acc);transform-origin:top;transform:scaleY(0)}
.rail-cap{font-family:var(--font-mono);font-size:.6rem;letter-spacing:.14em;color:var(--mut)}
.rail-txt{writing-mode:vertical-rl;transform:rotate(180deg);font-family:var(--font-mono);font-size:.6rem;letter-spacing:.32em;color:var(--mut);text-transform:uppercase}
@media(min-width:1100px){
  .rail{display:flex}
  .site{padding-left:var(--rail)}
}

/* ---------- topbar ---------- */
.topbar{position:sticky;top:0;z-index:100;background:var(--bg);border-bottom:1px solid var(--line)}
.tb-in{max-width:var(--wrap);margin:0 auto;padding:.8rem 1.25rem;display:flex;align-items:center;gap:1rem;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:.6rem;text-decoration:none;color:var(--ink);font-family:var(--font-px);font-size:.95rem;letter-spacing:.04em}
.brand-pad{width:10px;height:10px;background:var(--acc);box-shadow:0 0 10px var(--acc)}
.brand small{font-family:var(--font-mono);font-size:.62rem;color:var(--mut);letter-spacing:.16em}
.nav{margin-left:auto}
.nav ul{display:flex;gap:1.6rem;list-style:none;flex-wrap:wrap}
.nav a{position:relative;text-decoration:none;color:var(--mut);font-family:var(--font-mono);font-size:.74rem;letter-spacing:.14em;text-transform:uppercase;padding:.35rem 0;transition:color .2s}
.nav a::before{content:"";position:absolute;left:-12px;top:50%;width:6px;height:6px;margin-top:-3px;background:var(--acc);opacity:0;transition:opacity .2s}
.nav a:hover{color:var(--ink)}
.nav a.active{color:var(--ink)}
.nav a.active::before{opacity:1;box-shadow:0 0 8px var(--acc)}

/* theme switch */
.tt{margin-left:.5rem;position:relative;width:60px;height:28px;border:1px solid var(--line2);background:var(--panel);cursor:pointer;display:flex;align-items:center;justify-content:space-between;padding:0 6px;transition:border-color .2s,background .25s}
.tt:hover{border-color:var(--acc)}
.tt svg{width:13px;height:13px;color:var(--mut);z-index:1}
.tt-knob{position:absolute;top:3px;left:3px;width:20px;height:20px;background:var(--acc);transition:transform .25s ease}
:root[data-theme="dark"] .tt-knob{transform:translateX(32px)}

/* ---------- layout ---------- */
.wrap{max-width:var(--wrap);margin:0 auto;padding:0 1.25rem}
section{scroll-margin-top:86px}
.sec{padding:4.5rem 0 1rem}
.sec-head{display:flex;align-items:center;gap:1rem;margin-bottom:2.2rem}
.sh-index{font-family:var(--font-px);font-size:1rem;color:var(--acc)}
.sh-title{font-size:clamp(1.4rem,3vw,1.9rem);font-weight:700;letter-spacing:.01em;text-transform:uppercase}
.sh-rule{flex:1;height:1px;background:var(--line);position:relative;min-width:30px}
.sh-rule::after{content:"";position:absolute;right:0;top:-3px;width:7px;height:7px;background:var(--acc)}
.sh-meta{font-size:.62rem;letter-spacing:.2em;color:var(--mut);white-space:nowrap}

/* ---------- hero ---------- */
.hero{padding:clamp(3rem,8vh,6rem) 0 3rem;position:relative}
.hero-grid{display:grid;grid-template-columns:minmax(0,1.25fr) minmax(0,.9fr);gap:2.5rem;align-items:center}
.eyebrow{display:flex;align-items:center;gap:.7rem;font-family:var(--font-mono);font-size:.72rem;letter-spacing:.22em;color:var(--mut);text-transform:uppercase;margin-bottom:1.4rem}
.led{width:8px;height:8px;border-radius:50%;background:var(--ok);box-shadow:0 0 9px var(--ok);animation:blink 2.4s infinite}
.led-amb{background:var(--acc);box-shadow:0 0 9px var(--acc)}
@keyframes blink{0%,100%{opacity:1}50%{opacity:.35}}
.hero h1{font-size:clamp(2.1rem,6vw,4.3rem);line-height:1.05;font-weight:500;letter-spacing:-.015em}
.hero h1 .who{font-weight:700;color:var(--acc)}
.hero h1 .dotend{color:var(--acc)}
.hero-sub{max-width:34rem;margin-top:1.3rem;color:var(--mut);font-size:1.02rem}
.hero-links{display:flex;flex-wrap:wrap;gap:.8rem;margin-top:1.8rem}
.btn{display:inline-flex;align-items:center;gap:.5rem;text-decoration:none;font-family:var(--font-mono);font-size:.78rem;letter-spacing:.1em;text-transform:uppercase;border:1px solid var(--line2);color:var(--ink);padding:.65rem 1.05rem;position:relative;transition:border-color .2s,background .2s,color .2s,transform .2s}
.btn .arw{transition:transform .2s}
.btn:hover{border-color:var(--acc);background:var(--acc-soft)}
.btn:hover .arw{transform:translate(2px,-2px)}
.btn-solid{background:var(--acc);border-color:var(--acc);color:var(--bg);font-weight:600}
.btn-solid:hover{background:var(--acc);filter:brightness(1.08);color:var(--bg)}
.hero-meta{margin-top:1.8rem;font-size:.7rem;letter-spacing:.16em;color:var(--mut);text-transform:uppercase}

/* hero trace svg */
.hero-trace{width:100%;height:auto;max-height:340px}
.tr{stroke:var(--line2);stroke-width:1.5;fill:none;stroke-dasharray:5 9;animation:traceflow 7s linear infinite}
.tr-acc{stroke:var(--acc);stroke-dasharray:5 9}
.pad{fill:var(--bg);stroke:var(--acc);stroke-width:1.5}
.pad-b{animation:blink 3s infinite}
@keyframes traceflow{to{stroke-dashoffset:-280}}
@media(max-width:900px){.hero-grid{grid-template-columns:1fr}.hero-trace{display:none}}

/* ---------- ticker ---------- */
.ticker{border-block:1px solid var(--line);background:var(--panel);overflow:hidden;margin-top:1rem}
.ticker-track{display:flex;align-items:center;gap:2.4rem;width:max-content;padding:.6rem 0;animation:tick 30s linear infinite}
.ticker:hover .ticker-track{animation-play-state:paused}
.tk{font-family:var(--font-mono);font-size:.72rem;letter-spacing:.2em;text-transform:uppercase;color:var(--ink);white-space:nowrap}
.tk-sep{color:var(--acc);font-family:var(--font-mono);font-size:.72rem}
@keyframes tick{to{transform:translateX(-50%)}}

/* ---------- about ---------- */
.about-grid{display:grid;grid-template-columns:minmax(0,1.2fr) minmax(0,.9fr);gap:2.5rem;align-items:start}
.about-copy p{margin-bottom:1.1rem;color:var(--ink)}
.about-copy .dim{color:var(--mut)}
.about-copy .hl{color:var(--acc);font-weight:600}
.signal-path{display:flex;align-items:center;gap:.8rem;margin-top:1.6rem;flex-wrap:wrap}
.sp-node{font-family:var(--font-mono);font-size:.66rem;letter-spacing:.14em;border:1px solid var(--line2);padding:.45rem .7rem;color:var(--ink);background:var(--panel)}
.sp-node.mid{border-color:var(--acc);color:var(--acc)}
.sp-wire{flex:1 1 40px;min-width:26px;height:1px;background:repeating-linear-gradient(90deg,var(--line2) 0 5px,transparent 5px 10px)}
.datasheet{border:1px solid var(--line2);background:var(--panel);position:relative}
.datasheet::before,.datasheet::after{content:"";position:absolute;width:10px;height:10px;border:2px solid var(--acc)}
.datasheet::before{top:-2px;left:-2px;border-right:0;border-bottom:0}
.datasheet::after{bottom:-2px;right:-2px;border-left:0;border-top:0}
.ds-head{font-family:var(--font-px);font-size:.72rem;letter-spacing:.12em;padding:.8rem 1.1rem;border-bottom:1px solid var(--line);display:flex;justify-content:space-between;color:var(--mut)}
.datasheet dl{padding:.4rem 1.1rem 1rem}
.datasheet .row{display:flex;gap:1rem;padding:.62rem 0;border-bottom:1px dashed var(--line)}
.datasheet .row:last-child{border-bottom:0}
.datasheet dt{font-family:var(--font-mono);font-size:.64rem;letter-spacing:.16em;color:var(--mut);min-width:104px;padding-top:.2rem;text-transform:uppercase}
.datasheet dd{font-size:.92rem;flex:1}
@media(max-width:900px){.about-grid{grid-template-columns:1fr}}

/* ---------- skills ---------- */
.skill-groups{display:grid;grid-template-columns:repeat(2,1fr);gap:1.6rem}
.sg{border:1px solid var(--line);background:var(--panel);padding:1.2rem 1.2rem 1.3rem;position:relative;transition:border-color .25s,transform .25s,box-shadow .25s}
.sg:hover{border-color:var(--acc);transform:translateY(-3px);box-shadow:var(--shadow)}
.sg-head{display:flex;align-items:center;gap:.6rem;font-family:var(--font-mono);font-size:.68rem;letter-spacing:.2em;color:var(--mut);text-transform:uppercase;margin-bottom:1rem}
.sg-head::before{content:"";width:8px;height:8px;background:var(--acc)}
.chips{list-style:none;display:flex;flex-wrap:wrap;gap:.6rem}
.chips li{display:inline-flex;align-items:center;gap:.55rem;font-family:var(--font-mono);font-size:.78rem;border:1px solid var(--line2);padding:.42rem .7rem;background:var(--bg);transition:border-color .2s,background .2s,color .2s}
.chips li:hover{border-color:var(--acc);background:var(--acc-soft)}
@media(max-width:720px){.skill-groups{grid-template-columns:1fr}}

/* ---------- projects ---------- */
.proj-flow>*+*{margin-top:1.8rem}
.proj-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1.8rem}
.module{position:relative;display:flex;flex-direction:column;border:1px solid var(--line);background:var(--panel);transition:border-color .25s,transform .25s,box-shadow .25s}
.module:hover{border-color:var(--acc);transform:translateY(-4px);box-shadow:var(--shadow)}
.module::before,.module::after{content:"";position:absolute;width:14px;height:14px;border:2px solid var(--acc);opacity:0;transition:opacity .25s;pointer-events:none;z-index:2}
.module::before{top:-2px;left:-2px;border-right:0;border-bottom:0}
.module::after{bottom:-2px;right:-2px;border-left:0;border-top:0}
.module:hover::before,.module:hover::after,.module:focus-within::before,.module:focus-within::after{opacity:1}
.m-top{display:flex;align-items:center;gap:.9rem;padding:.8rem 1.1rem;border-bottom:1px dashed var(--line)}
.m-code{font-family:var(--font-px);font-size:.68rem;letter-spacing:.1em;color:var(--mut)}
.m-status{display:inline-flex;align-items:center;gap:.45rem;font-family:var(--font-mono);font-size:.62rem;letter-spacing:.18em;color:var(--mut);margin-left:auto}
.m-status .led{animation:none}
.m-body{padding:1.1rem 1.1rem 1.25rem;display:flex;flex-direction:column;gap:.9rem;flex:1}
.m-body h3{font-size:1.16rem;font-weight:700;line-height:1.25}
.m-desc{font-size:.9rem;color:var(--mut)}
.tags{display:flex;flex-wrap:wrap;gap:.45rem}
.tags span{font-family:var(--font-mono);font-size:.64rem;letter-spacing:.06em;border:1px solid var(--line);padding:.26rem .55rem;color:var(--mut);background:var(--bg)}
.m-links{margin-top:auto;padding-top:.9rem;border-top:1px solid var(--line);display:flex;flex-wrap:wrap;gap:.4rem 1.4rem}
.m-links a{font-family:var(--font-mono);font-size:.74rem;letter-spacing:.08em;text-decoration:none;color:var(--acc);display:inline-flex;gap:.4rem;align-items:center;padding:.2rem 0}
.m-links a .arw{transition:transform .2s}
.m-links a:hover .arw{transform:translate(2px,-2px)}
.m-links a:hover{text-decoration:underline}

/* featured module */
.featured{display:grid;grid-template-columns:minmax(0,1.1fr) minmax(0,1fr);border:1px solid var(--line2);background:var(--panel)}
.featured .m-media{border-right:1px dashed var(--line);display:flex;flex-direction:column}
.featured .m-media figure{flex:1;min-height:0}
.featured .m-body{padding:1.5rem}
.spec{list-style:none;border:1px dashed var(--line);padding:.9rem 1rem;display:flex;flex-direction:column;gap:.5rem;background:var(--bg)}
.spec li{font-family:var(--font-mono);font-size:.74rem;line-height:1.5;color:var(--mut)}
.spec b{color:var(--acc);font-weight:600;letter-spacing:.1em}
@media(max-width:860px){.featured{grid-template-columns:1fr}.featured .m-media{border-right:0;border-bottom:1px dashed var(--line)}.proj-grid{grid-template-columns:1fr}}

/* ---------- filmstrip gallery ---------- */
.filmstrip{display:flex;flex-direction:column;background:var(--bg2)}
.fs-viewer{position:relative;aspect-ratio:16/10;overflow:hidden;border-bottom:1px solid var(--line)}
.fs-slide{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;object-position:top;opacity:0;transition:opacity .35s ease}
.fs-slide.on{opacity:1}
.fs-main{position:absolute;inset:0;width:100%;height:100%;background:none;border:0;cursor:zoom-in}
.fs-main.no-lb{cursor:default}
.fs-arrow{position:absolute;top:50%;transform:translateY(-50%);z-index:3;width:34px;height:34px;display:flex;align-items:center;justify-content:center;background:var(--bg);border:1px solid var(--line2);color:var(--ink);cursor:pointer;font-size:.8rem;transition:background .2s,color .2s,border-color .2s}
.fs-arrow:hover{background:var(--acc);color:var(--bg);border-color:var(--acc)}
.fs-prev{left:.6rem}.fs-next{right:.6rem}
.fs-hud{position:absolute;left:.6rem;bottom:.6rem;z-index:3;background:var(--bg);border:1px solid var(--line2);padding:.2rem .55rem;font-family:var(--font-mono);font-size:.62rem;letter-spacing:.14em;color:var(--mut)}
.fs-hud b{color:var(--acc);font-weight:600}
.fs-thumbs{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;background:var(--line)}
.fs-thumb{position:relative;border:0;background:var(--bg2);padding:0;cursor:pointer;aspect-ratio:16/10;overflow:hidden;outline-offset:-3px}
.fs-thumb img{width:100%;height:100%;object-fit:cover;object-position:top;opacity:.65;transition:opacity .25s,transform .25s}
.fs-thumb:hover img{opacity:1}
.fs-thumb.on img{opacity:1}
.fs-thumb.on::after{content:"";position:absolute;inset:0;border:2px solid var(--acc)}
.fs-thumb .n{position:absolute;right:4px;bottom:3px;font-family:var(--font-mono);font-size:.55rem;color:#fff;text-shadow:0 1px 2px rgba(0,0,0,.8)}

/* ---------- lightbox ---------- */
dialog#lightbox{border:1px solid var(--line2);background:var(--panel);color:var(--ink);padding:0;width:min(960px,94vw);max-height:92vh}
dialog#lightbox::backdrop{background:rgba(7,9,13,.88)}
.lb-bar{display:flex;align-items:center;gap:1rem;padding:.7rem 1rem;border-bottom:1px solid var(--line)}
.lb-count{font-family:var(--font-mono);font-size:.72rem;letter-spacing:.18em;color:var(--acc)}
.lb-bar .btn{margin-left:auto;padding:.4rem .8rem;font-size:.68rem}
.lb-fig img{width:100%;max-height:68vh;object-fit:contain;background:var(--bg2)}
.lb-fig figcaption{padding:.8rem 1rem;font-size:.85rem;color:var(--mut);border-top:1px dashed var(--line)}
.lb-nav{display:flex;justify-content:space-between;gap:1rem;padding:.8rem 1rem;border-top:1px solid var(--line)}

/* ---------- contact ---------- */
.contact-grid{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(0,.95fr);gap:2.5rem;align-items:start}
.c-big{font-size:clamp(1.5rem,3.4vw,2.3rem);font-weight:700;line-height:1.2;margin-bottom:1rem}
.c-sub{color:var(--mut);margin-bottom:1.8rem}
.c-mail{display:inline-block;font-family:var(--font-mono);font-size:clamp(.95rem,2.4vw,1.3rem);color:var(--acc);text-decoration:none;border-bottom:2px solid var(--acc);padding-bottom:.15rem;overflow-wrap:anywhere;transition:color .2s,border-color .2s}
.c-mail:hover{color:var(--ink);border-color:var(--ink)}
.ports{list-style:none;border:1px solid var(--line2);background:var(--panel)}
.ports a{display:flex;align-items:center;gap:1rem;text-decoration:none;color:var(--ink);padding:1rem 1.1rem;border-bottom:1px solid var(--line);transition:background .2s,padding-left .2s}
.ports li:last-child a{border-bottom:0}
.ports a:hover{background:var(--acc-soft);padding-left:1.4rem}
.p-name{font-family:var(--font-mono);font-size:.72rem;letter-spacing:.2em;color:var(--acc);min-width:84px}
.p-val{font-size:.9rem;overflow-wrap:anywhere;flex:1}
.p-arw{color:var(--mut);transition:transform .2s}
.ports a:hover .p-arw{transform:translate(3px,-3px);color:var(--acc)}
@media(max-width:860px){.contact-grid{grid-template-columns:1fr}}

/* ---------- footer / back to top ---------- */
.site-footer{border-top:1px solid var(--line);margin-top:4.5rem;padding:1.6rem 0 2.2rem}
.ft{display:flex;flex-wrap:wrap;gap:.8rem 2rem;justify-content:space-between;font-family:var(--font-mono);font-size:.68rem;letter-spacing:.12em;color:var(--mut)}
.back-to-top{position:fixed;right:1.4rem;bottom:1.4rem;z-index:120;width:44px;height:44px;display:flex;align-items:center;justify-content:center;background:var(--panel);border:1px solid var(--line2);color:var(--ink);cursor:pointer;opacity:0;visibility:hidden;transform:translateY(10px);transition:opacity .3s,visibility .3s,transform .3s,border-color .2s,background .2s;font-size:1.05rem}
.back-to-top.show{opacity:1;visibility:visible;transform:none}
.back-to-top:hover{border-color:var(--acc);background:var(--acc-soft)}

@media(max-width:620px){
  .tb-in{gap:.6rem}
  .nav{margin-left:0;order:3;width:100%}
  .nav ul{justify-content:space-between;gap:.8rem}
  .sec{padding:3.2rem 0 1rem}
  .sh-meta{display:none}
  .wrap{padding:0 1rem}
}

/* ---------- reduced motion ---------- */
@media (prefers-reduced-motion: reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.01ms !important;animation-iteration-count:1 !important;transition-duration:.01ms !important}
  .rv{opacity:1;transform:none}
  .ticker-track{animation:none}
}