/* base.css — design tokens and site-wide components (third redesign, 2026-10-30).
   Bright, clean, mainstream academic homepage (al-folio / Hugo Academic conventions): white by default,
   one blue accent, Inter throughout, optional night mode through Quarto's navbar toggle.
   Light tokens on body.quarto-light (the default), night tokens on body.quarto-dark.
   Legacy class names (.glow-card, .btn-glow, .btn-ghost, .eyebrow, .text-grad) map to plain equivalents. */

body.quarto-light {
  --bg: #ffffff; --bg-2: #f8fafc; --bg-3: #f1f5f9; --surface: #ffffff;
  --line: #e5e7eb; --line-strong: #d1d5db;
  --ink: #111827; --ink-2: #374151; --muted: #6b7280; --faint: #9ca3af;
  --accent: #2563eb; --accent-ink: #1d4ed8; --accent-soft: #eff6ff; --accent-line: #bfdbfe;
  --shadow-sm: 0 1px 2px rgba(17,24,39,.05); --shadow: 0 1px 3px rgba(17,24,39,.06), 0 6px 16px rgba(17,24,39,.06);
  --shadow-lg: 0 4px 12px rgba(17,24,39,.08), 0 16px 40px rgba(17,24,39,.08);
  --hydrogen: #0d9488; --datacenter: #7c3aed; --carbon: #16a34a; --microgrid: #d97706; --wind: #0284c7;
}
body.quarto-dark {
  --bg: #111318; --bg-2: #161a21; --bg-3: #1c212a; --surface: #171b22;
  --line: #262b36; --line-strong: #343b48;
  --ink: #f3f4f6; --ink-2: #d1d5db; --muted: #9ca3af; --faint: #6b7280;
  --accent: #60a5fa; --accent-ink: #93c5fd; --accent-soft: #172033; --accent-line: #1e3a5f;
  --shadow-sm: none; --shadow: 0 1px 3px rgba(0,0,0,.4); --shadow-lg: 0 8px 30px rgba(0,0,0,.5);
  --hydrogen: #2dd4bf; --datacenter: #a78bfa; --carbon: #4ade80; --microgrid: #fbbf24; --wind: #38bdf8;
}
:root {
  --font: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, monospace;
  --r-sm: 6px; --r: 10px; --r-lg: 14px;
  --wrap: 1120px; --gutter: clamp(18px, 4vw, 40px); --nav-h: 60px;
  --ease: cubic-bezier(.25, .1, .25, 1);
}
.theme-hydrogen { --t: var(--hydrogen); } .theme-datacenter { --t: var(--datacenter); } .theme-carbon { --t: var(--carbon); }
.theme-microgrid { --t: var(--microgrid); } .theme-wind { --t: var(--wind); }

/* ---------- page ---------- */
body { background: var(--bg); color: var(--ink-2); font-family: var(--font); -webkit-font-smoothing: antialiased; }
h1, h2, h3, h4, h5, .title { font-family: var(--font); color: var(--ink); letter-spacing: -.015em; }
a { color: var(--accent); text-decoration: none; transition: color .15s var(--ease); }
a:hover { color: var(--accent-ink); text-decoration: underline; text-underline-offset: 3px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
@media (prefers-reduced-motion: no-preference) { html { scroll-behavior: smooth; } }
strong { color: var(--ink); }

/* ---------- navbar: white bar, thin rule, aligned with the content ---------- */
#quarto-header { position: sticky; top: 0; z-index: 1030; }
body.nav-fixed { padding-top: 0 !important; }   /* Quarto pads for a fixed header; ours is sticky */
#quarto-header .navbar { min-height: var(--nav-h); background: var(--bg) !important; border-bottom: 1px solid var(--line); box-shadow: none;
  transition: box-shadow .2s var(--ease); }
body.scrolled #quarto-header .navbar { box-shadow: var(--shadow-sm); }
#quarto-header .navbar > .container-fluid { max-width: calc(var(--wrap) + 2 * var(--gutter)); margin-inline: auto; padding-inline: var(--gutter); }
.navbar-brand .navbar-title { font-weight: 700; font-size: 1.12rem; color: var(--ink) !important; letter-spacing: -.01em; }
.navbar .nav-link { font-weight: 500; font-size: .94rem; color: var(--ink-2) !important; }
.navbar .nav-link:hover, .navbar .nav-link.active { color: var(--accent) !important; }
.navbar .nav-link.active { font-weight: 600; }
.navbar .quarto-color-scheme-toggle .bi, .navbar .bi { color: var(--muted); }

/* ---------- common components ---------- */
.label, .eyebrow { font-size: .75rem; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: var(--muted); }
.text-grad { color: var(--accent); }
.btn-solid, .btn-glow { display: inline-flex; align-items: center; gap: .45rem; padding: .55rem 1.05rem; border-radius: var(--r-sm);
  font-weight: 600; font-size: .92rem; color: #fff !important; background: var(--accent); border: 1px solid var(--accent); text-decoration: none !important;
  transition: background .15s var(--ease), box-shadow .15s var(--ease); }
.btn-solid:hover, .btn-glow:hover { background: var(--accent-ink); border-color: var(--accent-ink); box-shadow: var(--shadow); }
body.quarto-dark .btn-solid, body.quarto-dark .btn-glow { color: #0b1220 !important; }
.btn-outline, .btn-ghost { display: inline-flex; align-items: center; gap: .45rem; padding: .55rem 1.05rem; border-radius: var(--r-sm);
  font-weight: 500; font-size: .92rem; color: var(--ink) !important; background: var(--surface); border: 1px solid var(--line-strong); text-decoration: none !important;
  transition: border-color .15s var(--ease), color .15s var(--ease); }
.btn-outline:hover, .btn-ghost:hover { border-color: var(--accent); color: var(--accent) !important; }
/* small uppercase buttons under publications (al-folio style: ABS, DOI, CODE, BIB) */
.btn-xs { display: inline-flex; align-items: center; gap: .3rem; padding: .16rem .55rem; border-radius: 4px; font-size: .72rem; font-weight: 600;
  letter-spacing: .04em; text-transform: uppercase; color: var(--ink-2) !important; border: 1px solid var(--line-strong); background: var(--surface);
  text-decoration: none !important; cursor: pointer; transition: border-color .15s var(--ease), color .15s var(--ease), background .15s var(--ease); }
.btn-xs:hover, .btn-xs[aria-expanded="true"] { color: var(--accent) !important; border-color: var(--accent); background: var(--accent-soft); }
.chip { display: inline-flex; align-items: center; gap: .35rem; padding: .2rem .6rem; border-radius: 999px; font-size: .8rem;
  border: 1px solid var(--line); background: var(--bg-2); color: var(--ink-2); }
/* venue abbreviation badge (al-folio "abbr") */
.abbr { display: inline-flex; align-items: center; justify-content: center; min-width: 5.6rem; padding: .3rem .5rem; border-radius: 4px;
  font-size: .72rem; font-weight: 700; letter-spacing: .02em; color: #fff; background: var(--t, var(--accent)); text-align: center; line-height: 1.25; }
.card, .glow-card { position: relative; background: var(--surface); border: 1px solid var(--line); border-radius: var(--r); box-shadow: var(--shadow-sm);
  transition: box-shadow .2s var(--ease), border-color .2s var(--ease), transform .2s var(--ease); }
a.card:hover, a.glow-card:hover, .card.is-link:hover { box-shadow: var(--shadow-lg); border-color: var(--line-strong); transform: translateY(-2px); text-decoration: none; }
.section-title { display: flex; align-items: baseline; gap: .6rem; font-size: 1.45rem; font-weight: 700; margin: 2.6rem 0 1.1rem; }
.section-title a { font-size: .85rem; font-weight: 500; margin-left: auto; }

/* skip link and back-to-top button (site.js) */
.skip-link { position: absolute; left: 1rem; top: -100px; z-index: 2000; padding: .5rem .9rem; border-radius: var(--r-sm);
  background: var(--surface); color: var(--ink); border: 1px solid var(--accent); }
.skip-link:focus { top: .7rem; }
.to-top { position: fixed; right: 1.2rem; bottom: 1.2rem; z-index: 1035; width: 42px; height: 42px; border-radius: 50%; display: grid; place-items: center;
  background: var(--surface); color: var(--ink-2); border: 1px solid var(--line-strong); box-shadow: var(--shadow); cursor: pointer;
  opacity: 0; transform: translateY(8px); pointer-events: none; transition: opacity .2s var(--ease), transform .2s var(--ease); }
.to-top.show { opacity: 1; transform: none; pointer-events: auto; }
.to-top:hover { color: var(--accent); border-color: var(--accent); }

/* gentle fade-in (only once site.js runs) */
.js-reveal .reveal { opacity: 0; transform: translateY(10px); transition: opacity .5s var(--ease), transform .5s var(--ease); }
.js-reveal .reveal.in, .js-reveal .reveal:focus-within { opacity: 1; transform: none; }

/* ---------- footer ---------- */
.nav-footer { border-top: 1px solid var(--line); background: var(--bg-2) !important; font-size: .86rem; color: var(--muted); }
.nav-footer a { color: var(--ink-2); }
/* keep the footer's right-hand text clear of the back-to-top button at the bottom of the page (2026-11-05) */
@media (min-width: 768px) { .nav-footer .nav-footer-right { padding-right: 3.6rem; } }

@media (prefers-reduced-motion: reduce) {
  .js-reveal .reveal { opacity: 1; transform: none; transition: none; }
  .card, .glow-card, .btn-solid, .btn-outline, .btn-xs, .to-top { transition: none; }
}

main[tabindex="-1"]:focus { outline: none; }   /* programmatic focus target after "Back to top" */
.to-top[hidden] { display: none; }