/* ===== Design Tokens ===== */
:root {
  --primary: #38bdf8;
  --primary-deep: #0284c7;
  --accent: #fbbf24;
  --accent-deep: #f59e0b;
  --bg-base: #0b1026;
  --bg-alt: #0f152f;
  --surface: #131a33;
  --surface-alt: #1a2142;
  --border: rgba(56, 189, 248, 0.18);
  --border-strong: rgba(56, 189, 248, 0.32);
  --text: #f8fafc;
  --text-dim: #cbd5e1;
  --text-muted: #94a3b8;
  --shadow-md: 0 8px 28px rgba(0, 0, 0, 0.35);
  --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.45);
  --radius: 14px;
  --container: 1120px;
  --container-narrow: 780px;

  --font-heading: "Space Grotesk", system-ui, sans-serif;
  --font-body: "Inter", system-ui, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  color: var(--text);
  background: var(--bg-base);
  line-height: 1.7;
  font-size: 1.0625rem;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; height: auto; display: block; }

a { color: var(--primary); text-decoration: none; transition: color 0.2s ease; }
a:hover { color: var(--accent); }

h1, h2, h3, h4 { font-family: var(--font-heading); line-height: 1.25; color: var(--text); margin-block: 0 0.75em; font-weight: 600; }
h1 { font-size: clamp(2.25rem, 5vw, 3.75rem); font-weight: 700; letter-spacing: -0.02em; }
h2 { font-size: clamp(1.75rem, 3vw, 2.5rem); letter-spacing: -0.01em; }
h3 { font-size: 1.25rem; }
p { margin-block: 0 1.1em; color: var(--text-dim); }

/* ===== Containers & Sections ===== */
.container {
  max-width: var(--container);
  margin: 0 auto;
  padding-inline: clamp(1.25rem, 3vw, 2rem);
}
.container-narrow { max-width: var(--container-narrow); }

.section {
  padding-block: clamp(4rem, 8vw, 7rem);
  position: relative;
}
.section-alt { background: var(--bg-alt); }
.section-heading {
  font-family: var(--font-heading);
  margin-bottom: 1.5rem;
  position: relative;
  padding-left: 0.9rem;
}
.section-heading::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.3em;
  bottom: 0.3em;
  width: 3px;
  background: linear-gradient(180deg, var(--primary), var(--accent));
  border-radius: 2px;
}
.subheading {
  font-family: var(--font-heading);
  font-size: 1.05rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.center { text-align: center; }

/* ===== HERO ===== */
.hero {
  position: relative;
  overflow: hidden;
  min-height: 640px;
  padding-block: clamp(6rem, 10vw, 9rem) clamp(4rem, 8vw, 6rem);
  isolation: isolate;
}
.hero-bg {
  position: absolute;
  inset: 0;
  background-image: url('./assets/bg_hero.png');
  background-size: cover;
  background-position: center;
  z-index: -2;
}
.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 20% 10%, rgba(56, 189, 248, 0.12), transparent 60%),
    radial-gradient(ellipse at 80% 90%, rgba(251, 191, 36, 0.08), transparent 60%),
    linear-gradient(180deg, rgba(11, 16, 38, 0.55) 0%, rgba(11, 16, 38, 0.92) 100%);
  z-index: -1;
}
.hero-inner {
  max-width: 960px;
  margin: 0 auto;
  padding-inline: clamp(1.25rem, 3vw, 2rem);
  position: relative;
}
.hero-eyebrow {
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.85rem;
  color: var(--primary);
  margin-bottom: 1.25rem;
}
.hero-title {
  font-size: clamp(2.25rem, 5vw, 3.5rem);
  margin-bottom: 1.25rem;
  background: linear-gradient(180deg, #f8fafc 0%, #cbd5e1 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-authors {
  color: var(--text-muted);
  font-size: 0.95rem;
  margin-bottom: 1.25rem;
}
.hero-teaser {
  font-size: 1.15rem;
  max-width: 720px;
  color: var(--text-dim);
  margin-bottom: 2rem;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 0.75rem; margin-bottom: 2.5rem; }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 0.75rem 1.3rem;
  border-radius: 999px;
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: 0.01em;
  border: 1px solid var(--border-strong);
  background: rgba(56, 189, 248, 0.08);
  color: var(--text);
  transition: transform 0.18s ease, background 0.2s ease, box-shadow 0.2s ease;
}
.btn:hover { transform: translateY(-2px); background: rgba(56, 189, 248, 0.18); box-shadow: 0 4px 24px rgba(56, 189, 248, 0.25); color: var(--text); }
.btn-primary {
  background: linear-gradient(135deg, var(--primary), var(--primary-deep));
  border-color: transparent;
  color: #05101e;
}
.btn-primary:hover { color: #05101e; }

.hero-metrics {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
  max-width: 760px;
}
.metric-card {
  padding: 1.1rem 1.2rem;
  background: rgba(19, 26, 51, 0.6);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  backdrop-filter: blur(8px);
}
.metric-value {
  font-family: var(--font-heading);
  font-size: 1.6rem;
  font-weight: 700;
  color: var(--primary);
  line-height: 1.1;
}
.metric-unit { font-size: 0.95rem; color: var(--text-muted); margin-left: 0.3em; }
.metric-label {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-top: 0.4rem;
}

/* ===== Abstract ===== */
.abstract-card {
  padding: 2rem 2.25rem;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
  box-shadow: var(--shadow-md);
}
.abstract-card p { margin: 0; color: var(--text-dim); font-size: 1.05rem; }

/* ===== TL;DR grid ===== */
.tldr-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}
.tldr-card h3 { color: var(--text); margin-top: 0.4rem; }
.tldr-icon { font-size: 1.85rem; margin-bottom: 0.35rem; }

/* ===== Generic panel / card ===== */
.flecto-card, .flecto-callout, .flecto-panel, .flecto-note {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: clamp(1.25rem, 2.5vw, 1.75rem);
  box-shadow: var(--shadow-md);
  transition: transform 0.2s ease, border-color 0.2s ease;
  position: relative;
}
.flecto-card:hover { transform: translateY(-2px); border-color: var(--border-strong); }

.flecto-panel h3 { color: var(--text); margin-top: 0; }
.flecto-panel ul { margin: 0; padding-left: 1.25rem; color: var(--text-dim); }
.flecto-panel li { margin-block: 0.4rem; }

.flecto-callout {
  border-left: 3px solid var(--accent);
}
.flecto-callout h3 { margin-top: 0; color: var(--accent); font-size: 1.1rem; }

.flecto-note {
  border-left: 3px solid var(--primary);
  padding: 0.9rem 1.1rem;
  font-size: 0.95rem;
}

/* AI explanation label on explanation UI classes */
.flecto-note::before,
.flecto-callout::before,
.flecto-card::before,
.flecto-panel::before {
  content: "🤖 AI explanation";
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #60a5fa;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.5em;
}
/* Only show label on elements that are actual AI explanations (inserted during Step 6b) */
/* For the regular card/panel/callout used in the template, suppress the label */
.tldr-card::before,
.specialist-card::before,
.challenge-grid .flecto-card::before,
.bench-grid .flecto-card::before,
.artifact-regions::before,
.contribution-panel::before,
.related-panel::before { content: none; }
/* Generic suppression: template-level cards don't get the AI label */
.section .flecto-card::before,
.section .flecto-panel::before,
.section .flecto-callout::before { content: none; }
/* Re-enable for explicitly AI-marked explanations (used by Step 6b insertions) */
.flecto-note.ai-explain::before,
.flecto-card.ai-explain::before,
.flecto-callout.ai-explain::before,
.flecto-panel.ai-explain::before {
  content: "🤖 AI explanation";
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  color: #60a5fa;
  letter-spacing: 0.06em;
  display: block;
  margin-bottom: 0.5em;
}

/* ===== Chips ===== */
.chip {
  display: inline-block;
  padding: 0.25em 0.75em;
  border-radius: 999px;
  background: rgba(56, 189, 248, 0.12);
  color: var(--primary);
  font-family: var(--font-mono);
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-right: 0.4rem;
  margin-bottom: 0.35rem;
  border: 1px solid rgba(56, 189, 248, 0.22);
}
.chip-accent { background: rgba(251, 191, 36, 0.12); color: var(--accent); border-color: rgba(251, 191, 36, 0.25); }
.chip-cyan { background: rgba(56, 189, 248, 0.16); color: var(--primary); }

/* ===== Challenge grid ===== */
.challenge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

/* ===== Specialist grid ===== */
.specialist-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}
.specialist-card p { margin-top: 0.3rem; color: var(--text-dim); }

/* ===== Benchmark grid ===== */
.bench-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin-bottom: 1rem;
}

/* ===== Artifact regions panel ===== */
.artifact-regions { margin-top: 1.25rem; }
.region-row {
  display: grid;
  grid-template-columns: minmax(170px, 240px) 1fr;
  gap: 1rem;
  padding-block: 0.75rem;
  border-bottom: 1px solid var(--border);
  align-items: start;
}
.region-row:last-child { border-bottom: none; }
.region-path {
  font-family: var(--font-mono);
  color: var(--primary);
  background: rgba(56, 189, 248, 0.08);
  padding: 0.2em 0.55em;
  border-radius: 6px;
  font-size: 0.9rem;
  align-self: start;
}
.region-desc { color: var(--text-dim); }

/* ===== Analysis grid ===== */
.analysis-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1rem;
  margin-top: 1.5rem;
}

/* ===== Figures ===== */
.paper-figure {
  margin: 2rem 0;
  padding: 1rem;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-md);
}
.paper-figure img {
  width: 100%;
  height: auto;
  border-radius: 8px;
  background: #fff;
}
.paper-figure figcaption {
  margin-top: 0.9rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  font-style: italic;
  text-align: center;
  line-height: 1.55;
}

/* ===== Equations ===== */
.eq {
  margin-block: 0.6em;
  text-align: center;
  font-size: 1.05rem;
  color: var(--text);
  overflow-x: auto;
}
.eq-explain { color: var(--text-dim); }

/* ===== Details (accordion) ===== */
details.flecto-panel { margin-bottom: 1rem; }
details.flecto-panel summary {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text);
  cursor: pointer;
  list-style: none;
  padding-right: 1.5rem;
  position: relative;
}
details.flecto-panel summary::-webkit-details-marker { display: none; }
details.flecto-panel summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 0;
  color: var(--primary);
  font-size: 1.4rem;
  line-height: 1;
  transition: transform 0.2s ease;
}
details[open].flecto-panel summary::after { content: "−"; }
details.flecto-panel p { margin-top: 0.9rem; }

/* ===== Meta footer ===== */
.meta-footer .tag-row { margin: 1rem 0; }
.meta-footer .meta-line { color: var(--text-muted); font-size: 0.9rem; }
.meta-footer .meta-link a { color: var(--primary); }

/* ===== Reveal animation ===== */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }

@media (prefers-reduced-motion: reduce) {
  .reveal { opacity: 1 !important; transform: none !important; transition: none !important; }
  * { animation: none !important; transition: none !important; }
}

/* ===== Responsive ===== */
@media (max-width: 720px) {
  .hero { min-height: unset; padding-block: 5rem 3rem; }
  .region-row { grid-template-columns: 1fr; gap: 0.3rem; }
  .hero-metrics { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 480px) {
  .hero-metrics { grid-template-columns: 1fr; }
}