/* ══════════════════════════════════════════
   AI HUB Knowledge Hub — Shared Styles
   ══════════════════════════════════════════ */

/* ── Reset ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: 'Segoe UI', 'Helvetica Neue', Arial, -apple-system, sans-serif;
  color: #1a1a1a; background: #fff;
  line-height: 1.7; overflow-x: hidden;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; }

/* ── Colors ── */
:root {
  --crimson: #C41E3A;
  --navy: #1B365D;
  --warm: #8B6F47;
  --black: #0A0A0A;
  --gray1: #444;
  --gray2: #666;
  --gray3: #767676;
  --gray4: #ddd;
  --lgray: #F5F5F3;
  --white: #fff;
}
.crimson { color: var(--crimson); }
.navy { color: var(--navy); }

/* ── Typography ── */
h1, h2, h3, h4 { font-weight: 700; line-height: 1.2; }
.sans { font-family: 'Calibri', 'Segoe UI', 'Helvetica Neue', Arial, sans-serif; }
.tag {
  font-family: 'Calibri', 'Segoe UI', sans-serif;
  font-size: 0.7rem; letter-spacing: 0.15em;
  text-transform: uppercase; font-weight: 700;
  display: inline-block;
}
.tag.crimson { color: var(--crimson); }

/* ── Layout ── */
.section { padding: 5rem 2rem; }
.container { max-width: 1200px; margin: 0 auto; }
.dark { background: var(--black); color: var(--white); }

/* ── Section Headers ── */
.section-header { margin-bottom: 3rem; }
.section-header .tag { margin-bottom: 0.5rem; }
.section-header h2 { font-size: 2.2rem; margin-bottom: 0.8rem; }
.section-header p { font-size: 1rem; color: var(--gray2); max-width: 600px; }
.accent-line { width: 60px; height: 3px; background: var(--crimson); }
.divider { width: 100%; height: 1px; background: var(--gray4); margin: 2rem 0; }
.dark .divider { background: rgba(255,255,255,0.15); }

/* ── Global Focus Styles ── */
:focus-visible {
  outline: 2px solid var(--crimson);
  outline-offset: 3px;
}
:focus:not(:focus-visible) { outline: none; }

/* ── Skip Link ── */
.skip-link {
  position: absolute; top: -100%; left: 1rem;
  background: var(--crimson); color: var(--white);
  padding: 0.5rem 1rem; font-size: 0.85rem; font-weight: 700;
  z-index: 99999; transition: top 0.2s;
}
.skip-link:focus { top: 1rem; }

/* ══════════════════════════════════════════
   NAV
   ══════════════════════════════════════════ */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.95); backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--gray4);
  transition: box-shadow 0.3s;
}
nav.scrolled { box-shadow: 0 2px 20px rgba(0,0,0,0.06); }
.nav-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.8rem 2rem;
}
.logo { font-size: 1.1rem; font-weight: 700; color: var(--black); }
.logo span { color: var(--crimson); }
.nav-right { display: flex; align-items: center; gap: 2rem; }
.nav-label { font-family: 'Calibri', sans-serif; font-size: 0.75rem; color: var(--gray3); letter-spacing: 0.05em; }
.nav-links { list-style: none; display: flex; gap: 1.5rem; }
.nav-links a {
  font-family: 'Calibri', sans-serif; font-size: 0.8rem;
  color: var(--gray2); transition: color 0.2s; letter-spacing: 0.02em;
}
.nav-links a:hover { color: var(--crimson); }
.nav-links a.active { color: var(--crimson); font-weight: 700; }

/* ── Hamburger Button ── */
.nav-hamburger {
  display: none; flex-direction: column; gap: 5px;
  cursor: pointer; padding: 0.4rem; background: none; border: none;
}
.nav-hamburger span {
  display: block; width: 22px; height: 2px;
  background: var(--black); transition: all 0.25s ease;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ══════════════════════════════════════════
   HERO (Top Page)
   ══════════════════════════════════════════ */
.hero {
  min-height: 100vh; display: flex; align-items: center;
  position: relative; padding: 0 2rem;
}
.hero::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0;
  height: 3px; background: var(--crimson);
}
.hero-content { max-width: 800px; padding-left: 4rem; }
.hero-tag { margin-bottom: 1rem; color: var(--gray3); }
.hero h1 {
  font-size: 7rem; color: var(--black);
  letter-spacing: -0.04em; line-height: 0.9; margin-bottom: 0.5rem;
}
.hero-sub {
  font-size: 1.6rem; color: var(--gray2); font-weight: 400; margin-bottom: 2rem;
}
.hero .accent-line { margin-bottom: 2rem; }
.hero-desc { font-size: 1.05rem; color: var(--gray2); line-height: 1.8; }
.hero-scroll {
  position: absolute; bottom: 3rem; left: 50%;
  transform: translateX(-50%); text-align: center;
  display: block; color: inherit;
}
.hero-scroll span { font-family: 'Calibri', sans-serif; font-size: 0.65rem; color: var(--gray3); letter-spacing: 0.2em; text-transform: uppercase; }
.scroll-line { width: 1px; height: 40px; background: var(--gray4); margin: 0.5rem auto 0; animation: scrollPulse 2s infinite; }
@keyframes scrollPulse { 0%,100%{opacity:0.3} 50%{opacity:1} }

/* ══════════════════════════════════════════
   CATEGORY CARDS (Top Page)
   ══════════════════════════════════════════ */
.cat-grid {
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 1.5rem; margin-top: 1rem;
}
.cat-grid .cat-card:last-child:nth-child(odd) {
  grid-column: 1 / -1;
}
.cat-card {
  display: block; position: relative;
  padding: 2.5rem; background: var(--white);
  border: 1px solid var(--gray4);
  transition: all 0.25s ease; overflow: hidden;
  cursor: pointer;
}
.cat-card:hover {
  border-color: var(--crimson);
  box-shadow: 0 8px 30px rgba(0,0,0,0.06);
  transform: translateY(-3px);
}
.cat-card:focus-visible {
  border-color: var(--crimson);
  box-shadow: 0 8px 30px rgba(196,30,58,0.12);
}
.cat-num {
  font-family: 'Calibri', sans-serif; font-size: 3rem;
  font-weight: 700; color: var(--gray4); line-height: 1;
  position: absolute; top: 1.5rem; right: 2rem;
  transition: color 0.25s, transform 0.25s;
}
.cat-card:hover .cat-num { color: var(--crimson); transform: scale(1.05); }
.cat-accent { width: 40px; height: 3px; margin-bottom: 1.5rem; }
.cat-card h3 { font-size: 1.3rem; margin-bottom: 0.8rem; line-height: 1.4; }
.cat-card > p { font-size: 0.9rem; color: var(--gray2); line-height: 1.7; margin-bottom: 1.2rem; }
.cat-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.cat-tags span {
  font-family: 'Calibri', sans-serif; font-size: 0.65rem;
  padding: 0.2rem 0.6rem; background: var(--lgray);
  color: var(--gray2); letter-spacing: 0.03em;
}
.cat-arrow {
  position: absolute; bottom: 2rem; right: 2rem;
  font-size: 1.2rem; color: var(--gray4);
  transition: all 0.25s;
}
.cat-card:hover .cat-arrow { color: var(--crimson); transform: translateX(4px); }

/* ══════════════════════════════════════════
   LEVEL CARDS (Who Is This For)
   ══════════════════════════════════════════ */
.level-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 2rem; }
.level-card { padding: 2rem; border: 1px solid var(--gray4); transition: border-color 0.2s; }
.level-card:hover { border-color: var(--crimson); }
.level-icon { margin-bottom: 1.5rem; }
.level-card h3 { font-size: 1.1rem; margin-bottom: 0.5rem; }
.level-card > p { font-size: 0.85rem; color: var(--gray2); margin-bottom: 1.5rem; }
.level-links { display: flex; flex-direction: column; gap: 0.5rem; }
.level-links a {
  font-family: 'Calibri', sans-serif; font-size: 0.8rem;
  color: var(--crimson); transition: opacity 0.2s;
}
.level-links a:hover { opacity: 0.7; }

/* ══════════════════════════════════════════
   SUB-PAGE HERO
   ══════════════════════════════════════════ */
.page-hero {
  padding: 8rem 2rem 4rem; position: relative;
}
.page-hero::before {
  content: ''; position: absolute; top: 0; left: 0; right: 0;
  height: 3px; background: var(--crimson);
}
.page-hero .container { max-width: 1200px; margin: 0 auto; }
.page-hero .page-num {
  font-family: 'Calibri', sans-serif; font-size: 5rem;
  font-weight: 700; color: var(--gray4); line-height: 1;
}
.page-hero h1 { font-size: 2.8rem; margin: 0.5rem 0; }
.page-hero .page-lead { font-size: 1.05rem; color: var(--gray2); max-width: 700px; margin-top: 1rem; }
.page-hero .accent-line { margin-top: 1.5rem; }

/* ══════════════════════════════════════════
   CONTENT BLOCKS (Sub Pages)
   ══════════════════════════════════════════ */

/* Text + Visual split */
.content-split { display: grid; grid-template-columns: 1fr 1fr; gap: 4rem; align-items: start; }

/* Info Cards */
.info-card {
  padding: 2rem; border-left: 3px solid var(--gray4);
  background: var(--lgray); transition: transform 0.2s;
}
.info-card:hover { transform: translateX(6px); }
.info-card.crimson { border-left-color: var(--crimson); }
.info-card.navy { border-left-color: var(--navy); }
.info-card.warm { border-left-color: var(--warm); }
.info-card h4 { font-size: 1rem; margin-bottom: 0.3rem; }
.info-card p { font-size: 0.85rem; color: var(--gray2); margin: 0; line-height: 1.7; }

/* Prompt Compare */
.prompt-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 1.5rem; }
.prompt-box { padding: 1.8rem; border: 1px solid var(--gray4); }
.prompt-box.insight { border-color: var(--crimson); background: rgba(196,30,58,0.02); }
.prompt-box .prompt-label {
  font-family: 'Calibri', sans-serif; font-size: 0.65rem; font-weight: 700;
  letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 0.8rem;
}
.prompt-box.simple .prompt-label { color: var(--gray3); }
.prompt-box.insight .prompt-label { color: var(--crimson); }
.prompt-box blockquote { font-size: 0.95rem; font-style: italic; color: var(--gray1); }

/* Step Flow */
.step-flow { display: grid; grid-template-columns: repeat(var(--cols, 4), 1fr); gap: 2rem; }
.step-item .step-num { font-family: 'Calibri', sans-serif; font-size: 2rem; font-weight: 700; color: var(--crimson); }
.step-item h4 { font-size: 1.05rem; margin: 0.2rem 0 0.6rem; }
.step-item .step-line { width: 100%; height: 1px; background: var(--gray4); margin-bottom: 0.6rem; }
.step-item p { font-size: 0.85rem; color: var(--gray2); line-height: 1.7; }

/* Agent Row */
.agent-row {
  display: grid; grid-template-columns: 50px 180px 1fr;
  gap: 1rem; align-items: start; padding: 1.3rem 0;
  border-bottom: 1px solid var(--gray4); transition: background 0.2s;
}
.agent-row:hover { background: var(--lgray); margin: 0 -1rem; padding-left: 1rem; padding-right: 1rem; }
.agent-row:last-child { border-bottom: none; }
.agent-num { font-family: 'Calibri', sans-serif; font-size: 1.3rem; font-weight: 700; }

/* Tool Card Grid */
.tool-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1.5rem; }
.tool-card { padding: 1.5rem; border-top: 2px solid var(--crimson); }
.tool-card.navy-top { border-top-color: var(--navy); }
.tool-card h4 { font-family: 'Calibri', sans-serif; font-size: 0.85rem; font-weight: 700; color: var(--crimson); }
.tool-card.navy-top h4 { color: var(--navy); }
.tool-card p { font-size: 0.8rem; color: var(--gray2); margin: 0.4rem 0; }
.tool-card .metric { font-family: 'Calibri', sans-serif; font-size: 0.8rem; font-weight: 700; color: var(--navy); }
.tool-card .tool-status {
  display: inline-block; font-family: 'Calibri', sans-serif; font-size: 0.6rem;
  font-weight: 700; letter-spacing: 0.08em; padding: 0.15rem 0.5rem;
  margin-top: 0.5rem;
}
.tool-status.live { background: #E8F5E9; color: #2E7D32; }
.tool-status.dev { background: #FFF3E0; color: #E65100; }
.tool-status.planned { background: var(--lgray); color: var(--gray2); }

/* Case Row */
.case-row {
  display: grid; grid-template-columns: 200px 1fr; gap: 2rem;
  padding: 1.3rem 0; border-bottom: 1px solid var(--gray4); align-items: start;
}
.case-row:last-child { border-bottom: none; }
.case-client { font-family: 'Calibri', sans-serif; font-size: 0.7rem; font-weight: 700; color: var(--crimson); letter-spacing: 0.1em; }
.case-cat { font-family: 'Calibri', sans-serif; font-size: 0.65rem; color: var(--gray3); }
.case-title { font-size: 0.95rem; font-weight: 700; margin: 0.2rem 0 0; }
.case-desc { font-size: 0.85rem; color: var(--gray2); line-height: 1.7; }

/* Insight Box */
.insight-box {
  background: var(--lgray); padding: 2rem 2.5rem; margin-top: 2.5rem;
  font-size: 0.9rem; color: var(--gray1); font-style: italic; line-height: 1.8;
}
.dark .insight-box { background: rgba(255,255,255,0.05); }

/* ══════════════════════════════════════════
   BREADCRUMB
   ══════════════════════════════════════════ */
.breadcrumb {
  font-family: 'Calibri', sans-serif; font-size: 0.75rem;
  color: var(--gray3); margin-bottom: 1.5rem;
}
.breadcrumb a { color: var(--gray3); transition: color 0.2s; }
.breadcrumb a:hover { color: var(--crimson); }

/* ══════════════════════════════════════════
   ROLE TABS
   ══════════════════════════════════════════ */
.role-tabs { display: flex; gap: 0; border-bottom: 1px solid var(--gray4); margin-bottom: 2rem; }
.role-tab {
  font-family: 'Calibri', sans-serif; font-size: 0.8rem; font-weight: 600;
  padding: 0.8rem 1.5rem; color: var(--gray2); cursor: pointer;
  border-bottom: 2px solid transparent; transition: all 0.2s;
  background: none; border-top: none; border-left: none; border-right: none;
}
.role-tab:hover { color: var(--black); }
.role-tab.active { color: var(--crimson); border-bottom-color: var(--crimson); }

/* Role content */
.role-content { display: none; }
.role-content.active { display: block; }

/* ══════════════════════════════════════════
   PROMPT CODE BLOCKS (05-prompts)
   ══════════════════════════════════════════ */
.prompt-code-block {
  position: relative; background: var(--white);
  border: 1px solid var(--gray4); margin-top: 0.8rem;
}
.prompt-code-block pre {
  font-family: 'Courier New', Courier, monospace;
  font-size: 0.8rem; line-height: 1.7;
  padding: 1rem; white-space: pre-wrap;
  color: var(--gray1); overflow-x: auto;
}
.copy-btn {
  position: absolute; top: 0.5rem; right: 0.5rem;
  display: flex; align-items: center; gap: 0.3rem;
  font-family: 'Calibri', sans-serif; font-size: 0.65rem;
  font-weight: 600; letter-spacing: 0.05em;
  padding: 0.3rem 0.6rem; background: var(--lgray);
  border: 1px solid var(--gray4); color: var(--gray2);
  cursor: pointer; transition: all 0.2s;
}
.copy-btn:hover { background: var(--crimson); color: var(--white); border-color: var(--crimson); }
.copy-btn.copied { background: var(--navy); color: var(--white); border-color: var(--navy); }

/* ══════════════════════════════════════════
   NEXT CHAPTER CTA
   ══════════════════════════════════════════ */
.next-chapter {
  text-align: center; padding: 4rem 0;
}
.next-chapter h2 { margin: 1rem 0 0.5rem; }
.next-chapter p { color: var(--gray2); max-width: 500px; margin: 0 auto 1.5rem; }
.next-chapter-btn {
  display: inline-block; background: var(--crimson); color: var(--white);
  padding: 0.8rem 2rem; font-weight: 700; font-size: 0.85rem;
  letter-spacing: 0.03em; transition: opacity 0.2s;
}
.next-chapter-btn:hover { opacity: 0.85; }

/* ══════════════════════════════════════════
   COMING SOON
   ══════════════════════════════════════════ */
.coming-soon {
  padding: 4rem; text-align: center; border: 2px dashed var(--gray4);
  margin: 2rem 0;
}
.coming-soon h3 { font-size: 1.2rem; color: var(--gray2); margin-bottom: 0.5rem; }
.coming-soon p { font-size: 0.85rem; color: var(--gray2); }

/* ══════════════════════════════════════════
   FOOTER
   ══════════════════════════════════════════ */
footer {
  padding: 2rem; background: var(--black);
  border-top: 1px solid rgba(255,255,255,0.08);
}
.footer-inner {
  max-width: 1200px; margin: 0 auto;
  display: flex; justify-content: space-between; align-items: center;
}
.footer-brand { display: flex; align-items: baseline; gap: 1rem; }
.footer-brand .logo { font-size: 1rem; }
.footer-sub { font-family: 'Calibri', sans-serif; font-size: 0.75rem; color: var(--gray3); }
.footer-copy { font-family: 'Calibri', sans-serif; font-size: 0.65rem; color: var(--gray3); }

/* ══════════════════════════════════════════
   ANIMATION
   ══════════════════════════════════════════ */
.fade-in { opacity: 0; transform: translateY(25px); transition: opacity 0.6s ease, transform 0.6s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }

/* ── Staggered Children ── */
.cat-grid.visible .cat-card,
.level-grid.visible .level-card,
.tool-grid.visible .tool-card {
  opacity: 0; transform: translateY(20px);
  animation: fadeUp 0.5s ease forwards;
}
.cat-grid.visible .cat-card:nth-child(1),
.level-grid.visible .level-card:nth-child(1),
.tool-grid.visible .tool-card:nth-child(1) { animation-delay: 0.05s; }
.cat-grid.visible .cat-card:nth-child(2),
.level-grid.visible .level-card:nth-child(2),
.tool-grid.visible .tool-card:nth-child(2) { animation-delay: 0.15s; }
.cat-grid.visible .cat-card:nth-child(3),
.level-grid.visible .level-card:nth-child(3),
.tool-grid.visible .tool-card:nth-child(3) { animation-delay: 0.25s; }
.cat-grid.visible .cat-card:nth-child(4),
.tool-grid.visible .tool-card:nth-child(4) { animation-delay: 0.35s; }
.cat-grid.visible .cat-card:nth-child(5) { animation-delay: 0.45s; }
@keyframes fadeUp { to { opacity: 1; transform: translateY(0); } }

/* ══════════════════════════════════════════
   RESPONSIVE
   ══════════════════════════════════════════ */
@media (max-width: 1100px) and (min-width: 901px) {
  .hero h1 { font-size: 5.5rem; }
  .hero-content { padding-left: 2rem; }
}

@media (max-width: 900px) {
  .hero h1 { font-size: 4rem; }
  .hero-content { padding-left: 0; }
  .cat-grid { grid-template-columns: 1fr; }
  .cat-grid .cat-card:last-child:nth-child(odd) { grid-column: auto; }
  .level-grid { grid-template-columns: 1fr; }
  .content-split { grid-template-columns: 1fr; }
  .prompt-grid { grid-template-columns: 1fr; }
  .step-flow { grid-template-columns: 1fr !important; }
  .tool-grid { grid-template-columns: 1fr 1fr; }
  .agent-row { grid-template-columns: 40px 1fr; }
  .agent-row > :nth-child(3) { grid-column: 1 / -1; }
  .case-row { grid-template-columns: 1fr; }
  .page-hero h1 { font-size: 2rem; }
  .role-tabs { overflow-x: auto; }
  .footer-inner { flex-direction: column; gap: 1rem; text-align: center; }

  /* Hamburger visible */
  .nav-hamburger { display: flex; }
  .nav-links {
    display: none; position: absolute; top: 100%; left: 0; right: 0;
    background: rgba(255,255,255,0.98); backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--gray4);
    flex-direction: column; padding: 1rem 2rem; gap: 0;
  }
  .nav-links.open { display: flex; }
  .nav-links li { border-bottom: 1px solid var(--gray4); }
  .nav-links a { display: block; padding: 0.8rem 0; font-size: 0.9rem; }
}

/* ── Reduced Motion ── */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .fade-in { opacity: 1; transform: none; }
  .scroll-line { animation: none; opacity: 0.6; }
  .cat-card:hover, .info-card:hover { transform: none; }
}