/* ============================================================
   LA BIBLE DE L'IA — GLOSSARY INDEX — DESIGN SYSTEM
   ============================================================ */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}

:root{
  --bg-page:#faf8f3;--bg-surface:#ffffff;--bg-elevated:#f5f3ee;
  --bg-infobox:#f8f4eb;--bg-dark:#1a1a2e;--bg-dark-surface:#24243e;
  --ink:#1a1a2e;--ink-secondary:#4a4a5a;--ink-tertiary:#7a7a8a;--ink-inverse:#faf8f3;
  --gold:#c9a84c;--gold-light:#e4c76b;--gold-glow:rgba(201,168,76,.15);
  --link:#2563eb;--link-hover:#1d4ed8;
  --border-light:rgba(0,0,0,.06);--border-medium:rgba(0,0,0,.1);
  --shadow-sm:0 1px 3px rgba(26,26,46,.06);--shadow-md:0 4px 12px rgba(26,26,46,.08);
  --shadow-lg:0 12px 32px rgba(26,26,46,.12);
  --font-display:'Playfair Display',Georgia,serif;
  --font-body:'DM Sans','Helvetica Neue',sans-serif;
  --font-ui:'DM Sans','Helvetica Neue',sans-serif;
  --font-mono:'JetBrains Mono',ui-monospace,'Cascadia Code','Fira Code',monospace;
  --radius-sm:6px;--radius-md:10px;--radius-lg:16px;
}

[data-theme="dark"]{
  --bg-page:#141425;--bg-surface:#1e1e38;--bg-elevated:#252547;
  --bg-infobox:#1e1e38;
  --ink:#e8e6e1;--ink-secondary:#b0aec0;--ink-tertiary:#8886a0;
  --link:#60a5fa;--link-hover:#93bbfd;
  --border-light:rgba(255,255,255,.08);--border-medium:rgba(255,255,255,.12);
  --shadow-sm:0 2px 8px rgba(0,0,0,.3);--shadow-md:0 4px 16px rgba(0,0,0,.4);
  --shadow-lg:0 12px 32px rgba(0,0,0,.5);
  --gold-glow:rgba(201,168,76,.25);
}

html{scroll-behavior:smooth;font-size:16px}
body{background:var(--bg-page);color:var(--ink);font-family:var(--font-body);line-height:1.7;overflow-x:hidden}

/* Paper texture */
body::before{content:'';position:fixed;inset:0;pointer-events:none;z-index:9999;opacity:.3;
  background-image:url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.03'/%3E%3C/svg%3E");
  background-repeat:repeat;background-size:256px}

/* Scroll progress */
.scroll-progress{position:fixed;top:0;left:0;height:3px;z-index:10001;width:0;
  background:linear-gradient(90deg,var(--gold),var(--gold-light))}

/* Skip to main */
.skip-to-main{position:absolute;top:-50px;left:50%;transform:translateX(-50%);
  background:var(--gold);color:var(--bg-dark);padding:.7rem 1.5rem;border-radius:0 0 8px 8px;
  font-family:var(--font-ui);font-weight:600;font-size:.9rem;z-index:10002;
  transition:top .3s;text-decoration:none}
.skip-to-main:focus{top:0}

/* ============================================================
   TYPOGRAPHY
   ============================================================ */
h1,h2,h3{font-family:var(--font-display);line-height:1.2}
h1{font-size:clamp(2.2rem,5vw,4rem);font-weight:900}
h2{font-size:clamp(1.8rem,3.5vw,2.8rem);font-weight:900}
h3{font-size:1.3rem;font-weight:700}
a{color:var(--link);text-decoration:none;transition:color .2s}
a:hover{color:var(--link-hover)}
::selection{background:var(--gold-glow);color:var(--ink)}

/* ============================================================
   HERO
   ============================================================ */
.hero{min-height:70vh;display:flex;flex-direction:column;align-items:center;justify-content:center;
  text-align:center;padding:8rem 4vw 4rem;position:relative;overflow:hidden;
  background:linear-gradient(170deg,#0d0d1a 0%,var(--bg-dark) 40%,#1e1e3a 100%)}
.hero::after{content:'';position:absolute;bottom:-2px;left:0;right:0;height:150px;
  background:linear-gradient(to top,var(--bg-page),transparent)}
.hero-ornament{font-family:var(--font-display);font-size:.75rem;letter-spacing:.5em;text-transform:uppercase;
  color:var(--gold);margin-bottom:2rem;display:flex;align-items:center;gap:1.5rem;
  opacity:0;animation:fadeUp .8s .2s forwards}
.hero-ornament::before,.hero-ornament::after{content:'';width:60px;height:1px;background:var(--gold);opacity:.4}
.hero h1{color:var(--ink-inverse);max-width:850px;opacity:0;animation:fadeUp .8s .4s forwards}
.hero h1 em{font-style:italic;color:var(--gold)}
.hero-sub{font-family:var(--font-body);font-size:1.1rem;color:rgba(244,241,235,.45);
  max-width:600px;margin-top:1.2rem;font-weight:400;opacity:0;animation:fadeUp .8s .6s forwards}

/* Hero search */
.hero-search{margin-top:2.5rem;width:100%;max-width:600px;position:relative;opacity:0;animation:fadeUp .8s .8s forwards}
.hero-search input{width:100%;padding:1rem 1.5rem 1rem 3.2rem;border:2px solid rgba(244,241,235,.1);
  border-radius:12px;background:rgba(244,241,235,.06);color:var(--ink-inverse);font-family:var(--font-ui);
  font-size:1rem;outline:none;transition:all .3s}
.hero-search input::placeholder{color:rgba(244,241,235,.3)}
.hero-search input:focus{border-color:var(--gold);background:rgba(244,241,235,.1);box-shadow:0 0 30px rgba(201,168,76,.15)}
.hero-search-icon{position:absolute;left:1.1rem;top:50%;transform:translateY(-50%);
  width:20px;height:20px;stroke:rgba(244,241,235,.3);fill:none;stroke-width:2}

/* Hero stats */
.hero-stats{display:flex;gap:3rem;margin-top:2.5rem;opacity:0;animation:fadeUp .8s 1s forwards}
.hero-stat{text-align:center}
.hero-stat .num{font-family:var(--font-display);font-size:2rem;font-weight:700;color:var(--gold)}
.hero-stat .lbl{font-size:.7rem;font-family:var(--font-mono);color:rgba(244,241,235,.3);
  text-transform:uppercase;letter-spacing:.15em;margin-top:.2rem}
@media(max-width:600px){.hero-stats{gap:1.5rem;flex-wrap:wrap}.hero-stat .num{font-size:1.5rem}}

/* ============================================================
   BREADCRUMB
   ============================================================ */
.breadcrumb{padding:1.5rem 4vw .5rem;font-family:var(--font-ui);font-size:.82rem;color:var(--ink-tertiary)}
.breadcrumb a{color:var(--gold);text-decoration:none}
.breadcrumb a:hover{text-decoration:underline}
.breadcrumb span{margin:0 .4rem;opacity:.5}

/* ============================================================
   MAIN SECTION
   ============================================================ */
.section{padding:2rem 4vw 4rem;position:relative;max-width:1400px;margin:0 auto}

/* ============================================================
   CATEGORY FILTER PILLS
   ============================================================ */
.filter-bar{display:flex;flex-wrap:wrap;justify-content:center;gap:.5rem;margin-bottom:1.5rem}
.filter-pill{font-family:var(--font-ui);font-size:.78rem;font-weight:600;padding:.45rem 1rem;
  border-radius:20px;border:1px solid var(--border-light);background:var(--bg-surface);
  color:var(--ink-secondary);cursor:pointer;transition:all .3s}
.filter-pill:hover{border-color:var(--gold);color:var(--gold)}
.filter-pill.active{background:var(--gold);color:var(--bg-dark);border-color:var(--gold)}

/* ============================================================
   ALPHABET NAVIGATION BAR
   ============================================================ */
.alpha-bar{display:flex;flex-wrap:wrap;justify-content:center;gap:.35rem;margin:0 auto 1.5rem;max-width:900px;
  position:sticky;top:60px;z-index:100;background:var(--bg-page);padding:.8rem 0;
  border-bottom:1px solid var(--border-light)}
.alpha-btn{width:36px;height:36px;display:flex;align-items:center;justify-content:center;
  font-family:var(--font-display);font-weight:700;font-size:.9rem;
  border:1px solid var(--border-light);border-radius:var(--radius-sm);
  background:var(--bg-surface);color:var(--ink);cursor:pointer;transition:all .3s;text-decoration:none}
.alpha-btn:hover:not(.disabled){border-color:var(--gold);color:var(--gold);background:var(--gold-glow)}
.alpha-btn.active{background:var(--gold);color:var(--bg-dark);border-color:var(--gold)}
.alpha-btn.disabled{opacity:.2;cursor:default;pointer-events:none}

/* ============================================================
   RESULTS COUNTER
   ============================================================ */
.results-counter{font-family:var(--font-mono);font-size:.82rem;color:var(--ink-tertiary);
  text-align:center;margin-bottom:1.5rem}

/* ============================================================
   LETTER SECTIONS
   ============================================================ */
.letter-section{margin-bottom:2.5rem;scroll-margin-top:120px}
.letter-heading{font-family:var(--font-display);font-size:2.5rem;font-weight:900;color:var(--gold);
  padding-bottom:.5rem;border-bottom:2px solid var(--gold-glow);margin-bottom:1.2rem;
  display:flex;align-items:baseline;gap:.8rem}
.letter-heading .count{font-family:var(--font-mono);font-size:.75rem;color:var(--ink-tertiary);font-weight:400}

/* ============================================================
   TERM CARDS
   ============================================================ */
.terms-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1rem}
@media(max-width:1024px){.terms-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:600px){.terms-grid{grid-template-columns:1fr}}

.term-card{background:var(--bg-surface);border:1px solid var(--border-light);border-radius:var(--radius-lg);
  padding:1.4rem;transition:all .4s cubic-bezier(.22,1,.36,1);position:relative;overflow:hidden}
.term-card::before{content:'';position:absolute;top:0;left:0;right:0;height:3px;
  background:linear-gradient(90deg,var(--gold),var(--gold-light));opacity:0;transition:opacity .3s}
.term-card:hover{box-shadow:var(--shadow-lg);border-color:var(--gold);transform:translateY(-3px)}
.term-card:hover::before{opacity:1}
.term-card-tag{display:inline-block;font-family:var(--font-mono);font-size:.65rem;font-weight:600;
  letter-spacing:.08em;text-transform:uppercase;padding:.2rem .6rem;border-radius:4px;margin-bottom:.8rem}
.tag-concept{background:rgba(59,130,246,.1);color:#3b82f6}
.tag-technique{background:rgba(16,185,129,.1);color:#10b981}
.tag-modele{background:rgba(168,85,247,.1);color:#a855f7}
.tag-outil{background:rgba(245,158,11,.1);color:#f59e0b}
[data-theme="dark"] .tag-concept{background:rgba(59,130,246,.2);color:#60a5fa}
[data-theme="dark"] .tag-technique{background:rgba(16,185,129,.2);color:#34d399}
[data-theme="dark"] .tag-modele{background:rgba(168,85,247,.2);color:#c084fc}
[data-theme="dark"] .tag-outil{background:rgba(245,158,11,.2);color:#fbbf24}
.term-card-title{font-family:var(--font-display);font-size:1.15rem;font-weight:700;color:var(--ink);
  margin-bottom:.5rem;line-height:1.3}
.term-card-def{font-family:var(--font-ui);font-size:.85rem;color:var(--ink-secondary);line-height:1.6;
  margin-bottom:1rem}
.term-card-link{font-family:var(--font-ui);font-size:.8rem;font-weight:600;color:var(--gold);
  text-decoration:none;display:inline-flex;align-items:center;gap:.3rem;transition:gap .3s}
.term-card-link:hover{gap:.6rem;color:var(--gold-light)}
.term-card-en{font-family:var(--font-ui);font-size:.8rem;color:var(--ink-tertiary);
  margin-top:auto;padding-top:.5rem;border-top:1px solid var(--border-light)}

/* ============================================================
   NO RESULTS
   ============================================================ */
.no-results{text-align:center;padding:4rem 2rem;display:none}
.no-results-icon{font-size:3rem;margin-bottom:1rem}
.no-results h3{font-family:var(--font-display);margin-bottom:.5rem}
.no-results p{font-family:var(--font-ui);font-size:.9rem;color:var(--ink-secondary)}

/* ============================================================
   CTA SECTION
   ============================================================ */
.cta-section{background:linear-gradient(170deg,#0d0d1a 0%,var(--bg-dark) 40%,#1e1e3a 100%);
  padding:5rem 4vw;text-align:center}
.cta-section h2{color:var(--ink-inverse);margin-bottom:1rem}
.cta-section p{color:rgba(244,241,235,.45);font-family:var(--font-ui);max-width:500px;margin:0 auto 2rem;font-size:1rem}
.cta-btn{display:inline-flex;align-items:center;gap:.5rem;background:var(--gold);color:var(--bg-dark);
  font-family:var(--font-ui);font-size:1rem;font-weight:700;padding:.9rem 2rem;border-radius:var(--radius-md);
  text-decoration:none;transition:all .3s;border:none;cursor:pointer}
.cta-btn:hover{background:var(--gold-light);transform:translateY(-2px);box-shadow:0 8px 25px rgba(201,168,76,.3);color:var(--bg-dark)}

/* ============================================================
   BACK TO TOP
   ============================================================ */
.back-to-top{position:fixed;bottom:2rem;right:2rem;width:44px;height:44px;border-radius:50%;
  background:var(--gold);color:var(--bg-dark);border:none;cursor:pointer;font-size:1.2rem;
  display:flex;align-items:center;justify-content:center;opacity:0;visibility:hidden;
  transition:all .3s;z-index:500;box-shadow:var(--shadow-md)}
.back-to-top.visible{opacity:1;visibility:visible}
.back-to-top:hover{background:var(--gold-light);transform:translateY(-3px)}

/* ============================================================
   ANIMATIONS
   ============================================================ */
@keyframes fadeUp{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}
@keyframes fadeIn{from{opacity:0}to{opacity:1}}

/* Focus-visible */
:focus-visible{outline:2px solid var(--gold);outline-offset:2px}
a:focus-visible,button:focus-visible,select:focus-visible,input:focus-visible,
textarea:focus-visible,[tabindex]:focus-visible{outline:2px solid var(--gold);outline-offset:2px}
:focus:not(:focus-visible){outline:none}

/* Reduced motion */
@media(prefers-reduced-motion:reduce){
  *,*::before,*::after{
    animation-duration:0.01ms!important;animation-iteration-count:1!important;
    transition-duration:0.01ms!important;scroll-behavior:auto!important}
  html{scroll-behavior:auto}
}