/* The theory sub-site's own header: darkness falling off the top of the frame, no bar.
   Shared by /theory and the four theory pages; injected by theory-nav.js. */
.th-nav { position:absolute; top:0; left:0; right:0; z-index:1000; display:flex; align-items:baseline; justify-content:space-between; gap:16px; flex-wrap:wrap;
  padding:18px clamp(16px,4vw,40px) 36px; background:linear-gradient(to bottom, rgba(5,8,13,.94), rgba(5,8,13,.6) 55%, transparent);
  font-family:"Inter", system-ui, sans-serif; font-size:12px; letter-spacing:.02em; pointer-events:none; }
.th-nav a { pointer-events:auto; color:#9aa8b8; text-decoration:none; transition:color .4s ease; white-space:nowrap; }
.th-nav a:hover, .th-nav a[aria-current] { color:#e8b04b; }
.th-nav .th-home { color:#f4ede0; font-family:"Source Serif 4", Georgia, serif; font-size:15px; letter-spacing:0; }
.th-nav .th-home i { color:#6b7787; }
.th-nav .th-links { display:flex; flex-wrap:wrap; gap:6px 20px; }
@media (max-width:640px) { .th-nav .th-links { gap:6px 14px; } .th-nav { padding-bottom:28px; } }
/* a page with its own section nav keeps ours in the flow above it, so the two never overlap */
.th-nav.th-flow { position:relative; background:none; padding-bottom:14px; }
/* on this site the header matches the rest of it: the tracked name, the small tracked nav */
.th-nav .th-home { font-size:0.95rem; letter-spacing:0.34em; font-weight:500; text-transform:uppercase; color:#d6dee8; }
.th-nav .th-links a { font-size:0.7rem; letter-spacing:0.16em; text-transform:uppercase; }
@media (max-width:640px) { .th-nav .th-home { font-size:0.72rem; letter-spacing:0.18em; } .th-nav .th-links a { font-size:0.6rem; letter-spacing:0.08em; } }
/* the same spacing and tone as the site header (which sits under the site's lens vignette) */
.th-nav { padding: 1.1rem clamp(1rem, 5vw, 3.5rem) 2.2rem; }
.th-nav .th-home { color: #9399a1; }
.th-nav .th-links { gap: 6px clamp(0.9rem, 2.2vw, 2rem); }
.th-nav .th-links a { color: #727881; }
/* the site's footer, on this page too */
.th-foot { display:flex; flex-wrap:wrap; align-items:center; justify-content:space-between; gap:12px 24px; padding:1.1rem clamp(1rem, 5vw, 3.5rem) 1.6rem;
  font-family:"Inter", system-ui, sans-serif; font-size:0.72rem; letter-spacing:0.12em; color:#727881; }
.th-foot .th-foot-links { display:flex; align-items:center; gap:24px; }
.th-foot a { color:#727881 !important; text-decoration:none !important; transition:color .5s ease; }
.th-foot a:hover { color:#e8b04b !important; }
.th-foot .th-mail { font-family:"Source Serif 4", Georgia, serif; font-style:italic; letter-spacing:0; font-size:0.95rem; }