/* ===== RESET ===== */
*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}

/* ===== THEME ===== */
:root,[data-theme="dark"]{
  --bg-primary:#0a0a0a;
  --bg-secondary:#111111;
  --bg-card:#1a1a1a;
  --accent:#00d4aa;
  --accent-dim:#0f4c5c;
  --accent-glow:rgba(0,212,170,.15);
  --text-primary:#f0f0f0;
  --text-secondary:#888888;
  --border:#2a2a2a;
  --nav-bg:rgba(10,10,10,.88);
  --r:8px;
  --ff:'IBM Plex Sans',system-ui,sans-serif;
  --mono:'IBM Plex Mono',monospace;
  --nav-h:56px;
}
[data-theme="light"]{
  --bg-primary:#ffffff;
  --bg-secondary:#f5f6f7;
  --bg-card:#ffffff;
  --accent:#009e7e;
  --accent-dim:#b8e6d9;
  --accent-glow:rgba(0,158,126,.08);
  --text-primary:#1a1a1a;
  --text-secondary:#5a5a5a;
  --border:#e0e0e0;
  --nav-bg:rgba(255,255,255,.88);
}

html{scroll-behavior:smooth}
body{
  font-family:var(--ff);
  color:var(--text-primary);
  background:var(--bg-primary);
  line-height:1.7;
  -webkit-font-smoothing:antialiased;
}
a{color:var(--accent);text-decoration:none}
a:hover{color:var(--accent)}
a[href]::after{
  content:'';display:inline-block;
  width:1.2em;height:1.2em;margin-left:.2em;vertical-align:middle;
  background:currentColor;opacity:.45;
  -webkit-mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  mask-image:url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23000' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3E%3Cpath d='M18 13v6a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2V8a2 2 0 0 1 2-2h6'/%3E%3Cpolyline points='15 3 21 3 21 9'/%3E%3Cline x1='10' y1='14' x2='21' y2='3'/%3E%3C/svg%3E");
  -webkit-mask-size:contain;mask-size:contain;
  -webkit-mask-repeat:no-repeat;mask-repeat:no-repeat;
}
.top-nav a::after,
.repo-footer a::after,
.repo-item::after{content:none !important}
img{max-width:100%;display:block}
button{cursor:pointer;font-family:var(--ff)}

/* ===== NAV ===== */
.top-nav{
  position:fixed;top:0;left:0;right:0;height:var(--nav-h);
  background:var(--nav-bg);
  backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);
  z-index:200;display:flex;align-items:center;padding:0 2rem;
  border-bottom:1px solid var(--border);
}
.top-nav .brand{
  font-weight:700;font-size:.9rem;color:var(--text-primary);
  letter-spacing:.04em;text-transform:uppercase;margin-right:auto;
}
.nav-link{
  font-size:.73rem;font-weight:500;color:var(--text-secondary);
  letter-spacing:.03em;text-transform:uppercase;margin-right:1.2rem;
}
.nav-link:hover{color:var(--accent);opacity:1}
.theme-toggle{
  background:none;border:1px solid var(--border);
  color:var(--text-secondary);
  width:36px;height:36px;border-radius:50%;font-size:1.05rem;
  display:flex;align-items:center;justify-content:center;
}
.theme-toggle:hover{border-color:var(--accent);color:var(--accent)}

/* ===== REPO PAGE ===== */
.repo-page{
  max-width:1000px;margin:0 auto;
  padding:calc(var(--nav-h) + 2.5rem) 2rem 3rem;
}
.repo-title{
  font-size:2rem;font-weight:700;letter-spacing:-.02em;margin-bottom:.3rem;
}
.repo-subtitle{
  font-size:.88rem;color:var(--text-secondary);margin-bottom:3rem;
}

/* Sections */
.repo-section{margin-bottom:3rem}
.repo-section-label{
  font-size:.72rem;font-weight:700;text-transform:uppercase;
  letter-spacing:.1em;color:var(--accent);font-family:var(--mono);
  margin-bottom:1rem;padding-bottom:.4rem;border-bottom:1px solid var(--border);
}
.repo-count{
  font-weight:400;color:var(--text-secondary);letter-spacing:0;
}
.repo-section-desc{
  font-size:.82rem;color:var(--text-secondary);margin-bottom:1rem;margin-top:-.4rem;
}

/* Paper list */
.repo-list{display:flex;flex-direction:column;gap:.3rem}
.repo-item{
  display:flex;align-items:center;justify-content:space-between;
  padding:.55rem .9rem;
  border:1px solid var(--border);border-radius:var(--r);
  background:var(--bg-card);gap:1rem;
  color:var(--text-primary);
}
.repo-item:hover{border-color:var(--accent-dim);opacity:1}
.repo-item-title{
  font-size:.8rem;font-weight:500;
  white-space:nowrap;overflow:hidden;text-overflow:ellipsis;
  flex:1;min-width:0;
}
.repo-item-tag{
  font-size:.62rem;font-family:var(--mono);color:var(--text-secondary);
  text-transform:uppercase;letter-spacing:.04em;flex-shrink:0;
}

/* Engineering grid */
.eng-grid{
  display:grid;grid-template-columns:1fr 1fr;gap:1rem;
}
.eng-group{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--r);padding:1.1rem 1.3rem;
}
.eng-group:hover{border-color:var(--accent-dim)}
.eng-group h3{
  font-size:.82rem;font-weight:700;color:var(--accent);margin-bottom:.4rem;
}
.eng-group ul{list-style:none}
.eng-group li{
  font-size:.76rem;color:var(--text-secondary);
  padding:.1rem 0 .1rem .8rem;position:relative;
}
.eng-group li::before{content:'\2014';position:absolute;left:0;color:var(--accent-dim);font-size:.7rem}

/* Software grid */
.sw-grid{
  display:grid;grid-template-columns:1fr 1fr 1fr;gap:.8rem;
}
.sw-item{
  background:var(--bg-card);border:1px solid var(--border);
  border-radius:var(--r);padding:1rem;
}
.sw-item:hover{border-color:var(--accent-dim)}
.sw-item h3{font-size:.82rem;font-weight:600;margin-bottom:.1rem}
.sw-tech{
  font-size:.62rem;font-family:var(--mono);color:var(--accent);
  margin-bottom:.35rem;display:block;font-weight:500;
}
.sw-item p{font-size:.74rem;color:var(--text-secondary);line-height:1.55}

/* Circuit grid */
.circuit-grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(100px,1fr));gap:.5rem;
}

/* Galleries */
.gallery-group{margin-bottom:1.8rem}
.gallery-group:last-child{margin-bottom:0}
.gallery-group h3{
  font-size:.82rem;font-weight:700;color:var(--text-primary);margin-bottom:.5rem;
}
.gallery-grid{
  display:grid;grid-template-columns:repeat(auto-fill,minmax(140px,1fr));gap:.5rem;
}
.gallery-item{
  aspect-ratio:4/3;overflow:hidden;border-radius:var(--r);
  cursor:pointer;position:relative;border:1px solid var(--border);
  background:var(--bg-secondary);
}
.gallery-item img{width:100%;height:100%;object-fit:cover;transition:transform .2s}
.gallery-item:hover img{transform:scale(1.05)}
.g-label{
  position:absolute;bottom:0;left:0;right:0;
  background:rgba(0,0,0,.75);color:#fff;font-size:.62rem;
  padding:.2rem .4rem;opacity:0;transition:opacity .2s;
}
.gallery-item:hover .g-label{opacity:1}

/* Lightbox */
.lightbox{
  display:none;position:fixed;inset:0;z-index:500;
  background:rgba(0,0,0,.95);justify-content:center;align-items:center;padding:2rem;
}
.lightbox.active{display:flex}
.lightbox img{max-width:92vw;max-height:88vh;object-fit:contain;border-radius:var(--r)}
.lightbox-close{
  position:absolute;top:1.2rem;right:1.5rem;background:none;border:none;
  color:#fff;font-size:2.2rem;cursor:pointer;z-index:501;opacity:.7;
}
.lightbox-close:hover{opacity:1}
.lightbox-caption{
  position:absolute;bottom:1.5rem;left:50%;transform:translateX(-50%);
  color:rgba(255,255,255,.8);font-size:.85rem;text-align:center;font-family:var(--mono);
}

/* Footer */
.repo-footer{
  text-align:center;padding:2rem;font-size:.73rem;color:var(--text-secondary);
  border-top:1px solid var(--border);
}
.repo-footer a{color:var(--accent)}

/* Responsive */
@media(max-width:768px){
  .repo-page{padding:calc(var(--nav-h) + 1.5rem) 1.2rem 2rem}
  .eng-grid{grid-template-columns:1fr}
  .sw-grid{grid-template-columns:1fr 1fr}
  .nav-link{display:none}
}
@media(max-width:480px){
  .sw-grid{grid-template-columns:1fr}
  .repo-title{font-size:1.5rem}
}