/* ============================================================
 * FLAS project page styles
 * Inspired by cka-agent.github.io / turn-gate.github.io —
 * clean academic layout, light background, single accent.
 * ============================================================ */

:root {
  --accent: #116a8a;
  --accent-soft: #d8eaf1;
  --accent-strong: #0a4a62;
  --ink: #161a1d;
  --ink-soft: #3c4348;
  --dim: #6b7378;
  --line: #e3e6e8;
  --bg: #ffffff;
  --bg-tint: #f7f8f9;
  --bg-card: #ffffff;
  --code-bg: #f4f5f7;
  --max: 1200px;
  --narrow: 920px;
  --sidenav-w: 220px;
  --shadow-sm: 0 1px 2px rgba(20, 30, 40, 0.04),
               0 2px 8px rgba(20, 30, 40, 0.04);
  --shadow-md: 0 1px 2px rgba(20, 30, 40, 0.05),
               0 8px 28px rgba(20, 30, 40, 0.07);
  --radius: 14px;
  --radius-sm: 8px;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .15s ease, color .15s ease;
}
a:hover {
  color: var(--accent-strong);
  border-bottom-color: var(--accent);
}

code, pre, .mono {
  font-family: 'JetBrains Mono', 'SFMono-Regular', Consolas, monospace;
}

code {
  font-size: 0.92em;
  background: var(--code-bg);
  padding: 0.1em 0.35em;
  border-radius: 4px;
}

.container {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 36px;
}
.container.narrow { max-width: var(--narrow); }
.narrow { max-width: var(--narrow); margin-left: auto; margin-right: auto; }

/* ============================================================ LAYOUT
 * Above 1100px we use a 2-col layout: fixed sidenav on the left,
 * scrolling content on the right. Below, sidenav becomes a thin
 * sticky top bar.
 */
.main-col {
  margin-left: 0;
  min-height: 100vh;
}
@media (min-width: 1100px) {
  .main-col { margin-left: var(--sidenav-w); }
}

/* ============================================================ SIDENAV */
.sidenav {
  position: fixed;
  top: 0; left: 0;
  width: 100%;
  height: auto;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: saturate(140%) blur(8px);
  -webkit-backdrop-filter: saturate(140%) blur(8px);
  border-bottom: 1px solid var(--line);
  z-index: 50;
}
.sidenav-inner {
  display: flex;
  align-items: center;
  gap: 22px;
  padding: 12px 24px;
  overflow-x: auto;
}
.sidenav-brand {
  display: inline-flex;
  align-items: center;
  text-decoration: none;
  border-bottom: none;
  flex-shrink: 0;
}
.sidenav-brand:hover { border-bottom: none; }
.brand-logo {
  display: block;
  width: 36px;
  height: 36px;
  border-radius: 6px;
  transition: transform .15s ease;
}
.sidenav-brand:hover .brand-logo { transform: scale(1.05); }

.sidenav-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 4px;
  flex: 1;
}
.sidenav-list li { display: block; }
.sidenav-list a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  font-size: 13.5px;
  color: var(--ink-soft);
  border-bottom: none;
  border-radius: 6px;
  white-space: nowrap;
  transition: background-color .12s ease, color .12s ease;
}
.sidenav-list a::before {
  content: attr(data-num);
  font-family: 'JetBrains Mono', monospace;
  font-size: 11px;
  color: var(--dim);
  background: var(--bg-tint);
  padding: 1px 6px;
  border-radius: 3px;
}
.sidenav-list a:hover { background: var(--bg-tint); color: var(--ink); }
.sidenav-list a.active {
  color: var(--accent);
  background: var(--accent-soft);
}
.sidenav-list a.active::before { color: var(--accent); background: white; }

.sidenav-foot {
  display: flex;
  gap: 14px;
  flex-shrink: 0;
}
.sidenav-link {
  font-size: 12.5px;
  color: var(--dim);
  border-bottom: none;
  font-family: 'JetBrains Mono', monospace;
}
.sidenav-link:hover { color: var(--accent); border-bottom: none; }

@media (min-width: 1100px) {
  .sidenav {
    width: var(--sidenav-w);
    height: 100vh;
    border-right: 1px solid var(--line);
    border-bottom: none;
    overflow-y: auto;
  }
  .sidenav-inner {
    flex-direction: column;
    align-items: stretch;
    gap: 28px;
    padding: 28px 22px;
    overflow-x: visible;
  }
  .brand-logo { width: 56px; height: 56px; }
  .sidenav-list {
    flex-direction: column;
    gap: 2px;
    flex: initial;
  }
  .sidenav-list a { padding: 8px 12px; font-size: 14px; }
  .sidenav-foot {
    flex-direction: column;
    gap: 8px;
    margin-top: auto;
    padding-top: 22px;
    border-top: 1px solid var(--line);
  }
}

/* Ensure top of main content clears the mobile top-bar nav */
.hero { scroll-margin-top: 60px; }
.section { scroll-margin-top: 60px; }
@media (min-width: 1100px) {
  .hero { scroll-margin-top: 0; }
  .section { scroll-margin-top: 0; }
}

/* ============================================================ HERO */
.hero {
  padding: 84px 0 48px;
  background:
    radial-gradient(circle at 80% -10%,
                    var(--accent-soft) 0%,
                    rgba(216, 234, 241, 0) 55%),
    var(--bg);
  border-bottom: 1px solid var(--line);
}

.hero-eyebrow {
  font-size: 13px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 12px;
}

.hero-title {
  font-family: 'Source Serif 4', Georgia, serif;
  font-weight: 600;
  font-size: clamp(28px, 4.4vw, 44px);
  line-height: 1.18;
  letter-spacing: -0.01em;
  margin: 0 0 22px;
  color: var(--ink);
}

.hero-title .accent { color: var(--accent); }
.hero-title strong { font-weight: 700; }
.authors sup {
  color: var(--accent);
  font-weight: 600;
  font-size: 0.7em;
  margin-left: 1px;
}

.authors {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 18px;
  font-size: 15px;
  color: var(--ink-soft);
  margin-bottom: 22px;
}
.authors span { white-space: nowrap; }

.badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 28px;
}

.badge {
  display: inline-flex;
  align-items: stretch;
  font-size: 13px;
  font-weight: 500;
  border-radius: 6px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--bg-card);
  color: var(--ink-soft);
  border-bottom: 1px solid var(--line);
  transition: transform .15s ease, box-shadow .15s ease;
}
.badge:hover {
  color: var(--ink);
  border-color: var(--accent);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}
.badge-key {
  background: #f1f3f5;
  padding: 5px 10px;
  border-right: 1px solid var(--line);
  color: var(--ink-soft);
}
.badge-val {
  padding: 5px 10px;
  font-family: 'JetBrains Mono', monospace;
  font-size: 12.5px;
}
.badge.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}
.badge.primary .badge-key,
.badge.primary .badge-val {
  background: transparent;
  color: white;
  border-right-color: rgba(255,255,255,0.25);
}
.badge.primary:hover { background: var(--accent-strong); }

.tldr {
  font-size: 17px;
  line-height: 1.75;
  color: var(--ink-soft);
  border-left: 2px solid var(--accent);
  padding-left: 16px;
  margin: 0 0 32px;
}

.hero-figure {
  margin: 12px 0 0;
}
.hero-figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--line);
  background: white;
}

/* ===================================================== SECTIONS */
.section {
  padding: 72px 0;
  border-bottom: 1px solid var(--line);
}
.section:last-of-type { border-bottom: none; }
.section-tinted { background: var(--bg-tint); }

.section h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-weight: 600;
  font-size: 28px;
  letter-spacing: -0.005em;
  margin: 0 0 18px;
  display: flex;
  align-items: baseline;
  gap: 14px;
}

.section-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  font-weight: 500;
  color: var(--accent);
  background: var(--accent-soft);
  padding: 3px 9px;
  border-radius: 4px;
  position: relative;
  top: -3px;
}

.section p { margin: 0 0 14px; color: var(--ink-soft); }
.section p strong { color: var(--ink); }

.equation {
  margin: 26px 0;
  padding: 22px;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  text-align: center;
  font-size: 17px;
  overflow-x: auto;
}

/* Callout cards — under "How it works" */
.callouts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 14px;
  margin-top: 22px;
}
.callout {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  padding: 18px;
}
.callout-tag {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}
.callout p { margin: 0; font-size: 14.5px; line-height: 1.6; }

/* ============================================================ PLOTS */
.plot-card {
  margin-top: 26px;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.plot {
  width: 100%;
  min-height: 560px;
}
.plot.small { min-height: 420px; }

.plot-controls {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 18px 28px;
  padding: 16px 22px;
  background: var(--bg-tint);
  border-bottom: 1px solid var(--line);
  font-size: 14px;
}

.control {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink-soft);
}
.control.inline { gap: 8px; }
.control input[type="checkbox"] { accent-color: var(--accent); }

.control-label {
  font-weight: 500;
  color: var(--ink);
  font-size: 13.5px;
  letter-spacing: 0.01em;
  white-space: nowrap;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 220px;
  height: 4px;
  border-radius: 2px;
  background: linear-gradient(to right, var(--accent), var(--accent)) no-repeat,
              var(--line);
  background-size: var(--rng-fill, 50%) 100%;
  outline: none;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 2px solid var(--accent);
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(0,0,0,0.1);
  transition: transform .12s ease;
}
input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.15); }
input[type="range"]::-moz-range-thumb {
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 2px solid var(--accent);
  cursor: pointer;
}

output {
  font-family: 'JetBrains Mono', monospace;
  font-size: 13px;
  color: var(--accent);
  min-width: 60px;
}

select {
  font: inherit;
  font-size: 14px;
  padding: 6px 28px 6px 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--bg-card)
     url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='10' height='6' viewBox='0 0 10 6'><path fill='%2358636a' d='M0 0l5 6 5-6z'/></svg>")
     no-repeat right 10px center;
  appearance: none;
  -webkit-appearance: none;
  cursor: pointer;
  max-width: 460px;
}
select:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }

.plot-meta {
  padding: 10px 22px;
  background: var(--bg-card);
  border-top: 1px solid var(--line);
  font-size: 12.5px;
  color: var(--dim);
  font-family: 'JetBrains Mono', monospace;
}

/* =============================================== STUDIO WIDGET */
.studio { margin-top: 26px; }

.studio-pickers {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px 22px;
  margin-bottom: 18px;
}
.studio-pickers .control {
  flex-direction: column;
  align-items: stretch;
  gap: 6px;
}
.studio-pickers .control:last-child {
  grid-column: 1 / -1;
  flex-direction: row;
  align-items: center;
}
.studio-pickers select { width: 100%; max-width: none; }
.studio-pickers input[type="range"] { flex: 1; min-width: 200px; }

.studio-card {
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.studio-header {
  display: flex;
  justify-content: space-between;
  gap: 22px;
  padding: 18px 22px;
  background: var(--bg-tint);
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  flex-wrap: wrap;
}

.studio-meta-line {
  margin-bottom: 4px;
  line-height: 1.55;
}
.studio-meta-line .dim {
  color: var(--dim);
  font-size: 12.5px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  margin-right: 6px;
}

.studio-scores {
  display: flex;
  gap: 18px;
  align-items: center;
  flex-wrap: wrap;
  min-width: 280px;
}

.score-bar {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  min-width: 64px;
}
.score-bar .label {
  font-size: 11px;
  font-weight: 600;
  color: var(--dim);
  letter-spacing: 0.06em;
}
.score-bar .value {
  font-family: 'JetBrains Mono', monospace;
  font-size: 14px;
  color: var(--ink);
  margin-bottom: 4px;
}
.score-bar .track {
  width: 80px;
  height: 5px;
  background: var(--line);
  border-radius: 3px;
  overflow: hidden;
}
.score-bar .fill {
  height: 100%;
  background: var(--accent);
  transition: width .25s ease, background-color .25s ease;
}
.score-bar.bad .fill { background: #d4a02b; }
.score-bar.good .fill { background: #2a8a4a; }

.studio-output {
  padding: 22px;
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 16px;
  line-height: 1.75;
  color: var(--ink);
  white-space: pre-wrap;
  background: var(--bg-card);
  min-height: 240px;
  max-height: 480px;
  overflow-y: auto;
}

/* =============================================== PAPER FIGURE */
.paper-figure {
  margin: 26px 0 0;
  padding: 24px;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}
.paper-figure img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: var(--radius-sm);
}
.paper-figure figcaption {
  margin-top: 14px;
  font-size: 13.5px;
  line-height: 1.6;
  color: var(--dim);
  text-align: left;
}

/* =============================================== DEMO IFRAME */
.demo-card {
  margin-top: 22px;
  background: var(--bg-card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}
.demo-card-head {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 22px;
  background: linear-gradient(180deg, #fffaeb 0%, #ffffff 100%);
  border-bottom: 1px solid var(--line);
  font-size: 14px;
  color: var(--ink-soft);
}
.demo-tag {
  font-weight: 600;
  font-size: 12.5px;
  background: #ffd866;
  color: #2c1900;
  padding: 3px 9px;
  border-radius: 4px;
}
.demo-open {
  margin-left: auto;
  font-size: 13px;
  font-family: 'JetBrains Mono', monospace;
}
.demo-iframe-wrap {
  background: #fafafa;
}
.demo-iframe-wrap iframe {
  display: block;
  width: 100%;
  border: 0;
}

/* =============================================== CITATION */
.bibtex {
  margin: 18px 0 0;
  padding: 18px 22px;
  background: var(--code-bg);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  font-size: 13px;
  line-height: 1.65;
  color: var(--ink);
  overflow-x: auto;
}
.bibtex code {
  background: transparent;
  padding: 0;
  font-size: 13px;
}

/* =============================================== FOOTER */
.footer {
  padding: 36px 0 60px;
  font-size: 13.5px;
  color: var(--dim);
}
.footer-dim {
  margin-top: 6px;
  font-size: 12px;
  font-family: 'JetBrains Mono', monospace;
}

/* =============================================== RESPONSIVE */
@media (max-width: 720px) {
  .container { padding: 0 22px; }
  .section { padding: 56px 0; }
  .hero { padding: 56px 0 40px; }
  .hero-title { font-size: 30px; }
  .studio-pickers { grid-template-columns: 1fr; }
  .studio-pickers .control:last-child { flex-direction: column; align-items: stretch; }
  input[type="range"] { width: 100%; }
  .demo-iframe-wrap iframe { height: 520px; }
  .sidenav-foot { display: none; }
}