/* ===== DRIFT project page — custom styles ===== */
:root {
  --bg: #0d1117;
  --bg-soft: #161b22;
  --card: #1b2230;
  --border: #2a3240;
  --fg: #e6edf3;
  --fg-soft: #9aa7b4;
  --accent: #4f9cf9;
  --accent-2: #7c5cff;
  --good: #3fb950;
  --max-w: 980px;
  --radius: 14px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: "Inter", "Google Sans", system-ui, -apple-system, "Noto Sans", sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
.container { max-width: var(--max-w); margin: 0 auto; padding: 0 22px; }

/* ===== sticky nav ===== */
nav.topnav {
  position: sticky; top: 0; z-index: 50;
  background: rgba(13,17,23,.82);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}
nav.topnav .container {
  display: flex; align-items: center; justify-content: space-between;
  height: 56px;
}
nav.topnav .brand { font-weight: 700; letter-spacing: .04em; }
nav.topnav .links a {
  color: var(--fg-soft); margin-left: 20px; font-size: .92rem; font-weight: 500;
}
nav.topnav .links a:hover { color: var(--fg); text-decoration: none; }
@media (max-width: 640px){ nav.topnav .links a{ margin-left:13px; font-size:.82rem; } }

/* ===== hero ===== */
header.hero { padding: 64px 0 36px; text-align: center; }
.hero h1 {
  font-size: 2.35rem; line-height: 1.18; margin: 0 0 6px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.hero .venue { color: var(--fg-soft); font-weight: 600; letter-spacing:.05em; margin-bottom: 22px; }
.authors { font-size: 1.06rem; margin: 4px 0; }
.authors a { color: var(--fg); }
.authors sup { color: var(--accent); }
.affil { color: var(--fg-soft); font-size: .92rem; margin: 10px auto 0; max-width: 860px; line-height: 1.5; }
.affil .aff-item { display: block; margin: 2px 0; }   /* one affiliation per line */
.affil .aff-sep { display: none; }
.corr { color: var(--fg-soft); font-size: .82rem; margin-top: 6px; }

.btn-row { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 26px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  background: var(--card); border: 1px solid var(--border); color: var(--fg);
  padding: 10px 18px; border-radius: 999px; font-weight: 600; font-size: .95rem;
  transition: .15s;
}
.btn:hover { border-color: var(--accent); text-decoration: none; transform: translateY(-1px); }
.btn svg { width: 18px; height: 18px; fill: currentColor; }

/* ===== sections ===== */
section { padding: 48px 0; border-top: 1px solid var(--border); }
section h2 {
  font-size: 1.6rem; margin: 0 0 6px; text-align: center;
}
section .lead { color: var(--fg-soft); text-align: center; max-width: 720px; margin: 0 auto 30px; }
.abstract p { color: var(--fg); font-size: 1.02rem; }

figure { margin: 0; }
figure img { width: 100%; border-radius: var(--radius); border: 1px solid var(--border); background:#fff; }
figcaption { color: var(--fg-soft); font-size: .88rem; text-align: center; margin-top: 10px; }

/* ===== claim cards ===== */
.cards { display: grid; grid-template-columns: repeat(3,1fr); gap: 18px; margin-top: 8px; }
@media (max-width: 760px){ .cards{ grid-template-columns:1fr; } }
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px;
}
.card .num {
  display:inline-flex; width:30px; height:30px; align-items:center; justify-content:center;
  border-radius: 8px; background: linear-gradient(135deg,var(--accent),var(--accent-2));
  color:#fff; font-weight:700; margin-bottom: 12px;
}
.card h3 { margin: 0 0 6px; font-size: 1.06rem; }
.card p { margin: 0; color: var(--fg-soft); font-size: .94rem; }

/* ===== metric callouts ===== */
.metrics { display:grid; grid-template-columns: repeat(3,1fr); gap:18px; margin: 4px 0 30px; }
@media (max-width: 760px){ .metrics{ grid-template-columns:1fr; } }
.metric { background: var(--bg-soft); border:1px solid var(--border); border-radius: var(--radius); padding: 20px; text-align:center; }
.metric .v { font-size: 2rem; font-weight: 800; color: var(--good); }
.metric .k { color: var(--fg-soft); font-size: .9rem; margin-top: 4px; }

.vgrid { display:grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 760px){ .vgrid{ grid-template-columns:1fr; } }
.vgrid video { width:100%; border-radius:12px; border:1px solid var(--border); background:#000; display:block; }
.tag { display:inline-block; font-size:.72rem; font-weight:700; letter-spacing:.04em;
       padding:2px 8px; border-radius:6px; margin-bottom:6px; }
.tag.sim { background:rgba(79,156,249,.18); color:var(--accent); }
.tag.zs  { background:rgba(63,185,80,.18); color:var(--good); }

.grid2 { display:grid; grid-template-columns: 1fr 1fr; gap: 20px; }
.grid3 { display:grid; grid-template-columns: repeat(3,1fr); gap: 16px; }
@media (max-width: 760px){ .grid2,.grid3{ grid-template-columns:1fr; } }

/* ===== bibtex ===== */
pre.bibtex {
  background: var(--bg-soft); border:1px solid var(--border); border-radius: var(--radius);
  padding: 18px; overflow-x:auto; color: var(--fg); font-size: .86rem; line-height:1.55;
}

footer { padding: 40px 0; text-align:center; color: var(--fg-soft); font-size:.85rem; border-top:1px solid var(--border); }

/* ===== selector pills ===== */
.pills { display:flex; gap:8px; justify-content:center; flex-wrap:wrap; margin: 0 0 18px; }
.pill {
  background: var(--card); border:1px solid var(--border); color: var(--fg-soft);
  padding: 7px 16px; border-radius: 999px; font-weight:600; font-size:.9rem; cursor:pointer; transition:.15s;
}
.pill:hover { color: var(--fg); border-color: var(--accent); }
.pill.active { background: linear-gradient(135deg,var(--accent),var(--accent-2)); color:#fff; border-color:transparent; }
.pill-group { display:inline-flex; gap:8px; padding:4px; background:var(--bg-soft); border:1px solid var(--border); border-radius:999px; }

/* ===== before/after slider ===== */
.ba-slider {
  position: relative; max-width: 560px; margin: 0 auto; border-radius: var(--radius);
  overflow: hidden; border:1px solid var(--border); user-select:none; cursor:ew-resize; background:#000;
}
.ba-slider img { display:block; width:100%; pointer-events:none; }
.ba-before, .ba-after { position:relative; }
.ba-after { position:absolute; inset:0; clip-path: inset(0 0 0 50%); }
.ba-lab {
  position:absolute; top:10px; padding:3px 10px; border-radius:6px; font-size:.78rem; font-weight:700;
  background:rgba(0,0,0,.6); color:#fff; backdrop-filter: blur(2px);
}
.ba-before .ba-lab { left:10px; }
.ba-after .ba-lab { right:10px; }
.ba-handle {
  position:absolute; top:0; bottom:0; left:50%; width:2px; background:#fff; transform:translateX(-50%);
  box-shadow:0 0 6px rgba(0,0,0,.6); pointer-events:none;
}
.ba-handle::after {
  content:"⇆"; position:absolute; top:50%; left:50%; transform:translate(-50%,-50%);
  width:32px; height:32px; border-radius:50%; background:#fff; color:#111; font-size:15px;
  display:flex; align-items:center; justify-content:center; box-shadow:0 1px 6px rgba(0,0,0,.5);
}

/* ===== thickness slider ===== */
.thk-wrap { max-width: 760px; margin: 0 auto; }
.thk-img { width:100%; border-radius:var(--radius); border:1px solid var(--border); background:#000; display:block; }
.thk-controls { display:flex; align-items:center; gap:16px; margin-top:16px; }
.thk-range { flex:1; accent-color: var(--accent); height:6px; cursor:pointer; }
.thk-readout { min-width:170px; text-align:right; }
.thk-readout .thk-val-t { font-weight:800; font-size:1.15rem; }
.thk-readout .thk-val-x { color: var(--accent); font-size:.85rem; font-weight:600; }
.thk-axis { display:flex; justify-content:space-between; color:var(--fg-soft); font-size:.78rem; margin-top:2px; }

.hidden { display:none; }

.placeholder {
  display:flex; align-items:center; justify-content:center; text-align:center;
  min-height: 260px; border: 1px dashed var(--accent); border-radius: var(--radius);
  color: var(--fg-soft); background: var(--bg-soft); padding: 20px; font-size:.95rem;
}