/* ===== Design tokens AI — Ivoire / Marine / Cramoisi ===== */
:root {
  --ai-bg:         #14171c;
  --ai-surface:    #1c2029;
  --ai-text:       #e9e7df;
  --ai-muted:      #8b8f99;
  --ai-accent:     #4a6fa5;
  --ai-accent-alt: #b5443a;
  --ai-danger:     #a83232;
  --ai-radius:     8px;
  --ai-shadow:     0 2px 12px rgba(0,0,0,.5);
  --ai-transition: 0.2s ease;
}

[data-theme="light"] {
  --ai-bg:      #f4f1ea;
  --ai-surface: #ffffff;
  --ai-text:    #1c2029;
  --ai-muted:   #5c5f68;
}

body { background: var(--ai-bg); color: var(--ai-text); }

/* ===== Navigation ===== */
.ai-nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--ai-bg);
  border-bottom: 2px solid var(--ai-accent);
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0 1rem;
}
.ai-nav__home { color: var(--ai-accent); text-decoration: none; font-weight: 700; font-size: .9rem; padding: .7rem .5rem; white-space: nowrap; }
.ai-nav__links { display: flex; flex-wrap: wrap; justify-content: flex-end; }
.ai-nav__links a { color: var(--ai-text); text-decoration: none; padding: .7rem 1rem; font-size: .85rem; font-weight: 500; white-space: nowrap; transition: background var(--ai-transition), color var(--ai-transition); }
.ai-nav__links a:hover { background: var(--ai-surface); color: var(--ai-accent); }

#ai-concepts, #ai-auteur, #ai-dialogue { scroll-margin-top: 52px; }

/* ===== Hero ===== */
.ai-hero {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  padding: 3rem 1rem 2rem;
  background: linear-gradient(135deg, var(--ai-bg) 0%, #12151c 100%);
}
.ai-hero__cover { flex-shrink: 0; }
.ai-hero__cover-img { width: 200px; height: auto; border-radius: var(--ai-radius); box-shadow: var(--ai-shadow); }
.ai-hero__cover-placeholder { width: 200px; height: 300px; background: var(--ai-surface); border-radius: var(--ai-radius); display: flex; align-items: center; justify-content: center; text-align: center; padding: 1rem; }
.ai-hero__text h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); margin: 0 0 .5rem; color: var(--ai-accent); }
.ai-hero__subtitle { font-size: clamp(1rem, 2.5vw, 1.3rem); color: var(--ai-text); margin: 0 0 1rem; font-style: italic; }
.ai-hero__hook { color: var(--ai-text); line-height: 1.6; margin-bottom: 1rem; }

/* ===== Boutons & badge ===== */
.ai-btn { display: inline-block; padding: .75rem 1.5rem; border-radius: var(--ai-radius); font-weight: 600; text-decoration: none; cursor: pointer; border: none; transition: transform var(--ai-transition), opacity var(--ai-transition); }
.ai-btn--primary { background: var(--ai-accent); color: #fff; }
.ai-btn--primary:hover { transform: translateY(-1px); opacity: .92; }
.ai-btn:focus-visible { outline: 2px solid var(--ai-accent); outline-offset: 2px; }
.ai-badge-soon { display: inline-block; padding: .6rem 1.2rem; border-radius: var(--ai-radius); background: var(--ai-accent-alt); color: #fff; font-weight: 600; font-size: .9rem; }

/* ===== 4e de couverture ===== */
.ai-quatrieme { max-width: 720px; margin: 0 auto; padding: 2rem 1rem; line-height: 1.75; color: var(--ai-text); }
.ai-quatrieme p { margin: 0 0 1.1rem; }

/* ===== Concepts (périodes) ===== */
.ai-concepts { padding: 2.5rem 1rem; background: var(--ai-surface); }
.ai-concepts__title { text-align: center; font-size: clamp(1.4rem, 3vw, 2rem); margin: 0 0 .3rem; color: var(--ai-accent); }
.ai-concepts__subtitle { text-align: center; color: var(--ai-muted); margin: 0 0 2rem; }
.ai-concepts__grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 1.5rem; max-width: 1100px; margin: 0 auto; }
.ai-concept-card { background: var(--ai-bg); border-radius: var(--ai-radius); padding: 1.5rem; box-shadow: var(--ai-shadow); position: relative; }
.ai-concept-card__number { position: absolute; top: -14px; left: 1.2rem; background: var(--ai-accent); color: #fff; width: 32px; height: 32px; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: 700; }
.ai-concept-card__titre { margin: .8rem 0 .2rem; font-size: 1.1rem; }
.ai-concept-card__sous-titre { color: var(--ai-accent-alt); font-size: .9rem; margin: 0 0 .8rem; font-style: italic; }
.ai-concept-card__desc { color: var(--ai-text); line-height: 1.6; font-size: .93rem; }
.ai-concept-card__details { margin-top: .8rem; }
.ai-concept-card__details summary { cursor: pointer; color: var(--ai-accent); font-size: .85rem; }
.ai-concept-card__exemples { margin: .6rem 0 0; padding-left: 1.2rem; color: var(--ai-muted); font-size: .85rem; }

/* ===== Auteur ===== */
.ai-auteur { padding: 2.5rem 1rem; max-width: 720px; margin: 0 auto; }
.ai-auteur__title { text-align: center; color: var(--ai-accent); margin: 0 0 1.5rem; }
.ai-auteur__layout { display: flex; gap: 1.5rem; align-items: flex-start; flex-wrap: wrap; }
.ai-auteur__photo { width: 120px; height: 120px; border-radius: 50%; object-fit: cover; flex-shrink: 0; }
.ai-auteur__photo-placeholder { width: 120px; height: 120px; border-radius: 50%; background: var(--ai-surface); display: flex; align-items: center; justify-content: center; font-size: 2rem; flex-shrink: 0; }
.ai-auteur__bio-name { font-weight: 700; color: var(--ai-accent); margin: 0 0 .5rem; }
.ai-auteur__bio p { line-height: 1.65; margin: 0 0 .8rem; color: var(--ai-text); }
.ai-auteur__cta { text-align: center; margin-top: 1.5rem; }

/* ===== Dialogue IA ===== */
.ai-dialogue { padding: 2.5rem 1rem 3.5rem; background: var(--ai-surface); max-width: 760px; margin: 0 auto; border-radius: var(--ai-radius); }
.ai-dialogue-title { text-align: center; color: var(--ai-accent); margin: 0 0 .3rem; }
.ai-dialogue-subtitle { text-align: center; color: var(--ai-muted); margin: 0 0 1.5rem; font-size: .9rem; }
.ai-history { min-height: 80px; max-height: 420px; overflow-y: auto; margin-bottom: 1rem; }
.ai-dialogue-hint { color: var(--ai-muted); font-style: italic; text-align: center; }
.ai-msg { border-radius: var(--ai-radius); padding: .9rem 1.1rem; margin-bottom: .8rem; line-height: 1.6; }
.ai-msg-user { background: var(--ai-accent-alt); color: #fff; margin-left: 15%; }
.ai-msg-assistant { background: var(--ai-bg); color: var(--ai-text); margin-right: 5%; }
.ai-constante-block, .ai-cas-block { margin-top: .6rem; font-size: .85rem; color: var(--ai-muted); }
.ai-label { color: var(--ai-accent); font-weight: 600; }
.ai-questions { display: flex; flex-wrap: wrap; gap: .5rem; margin-top: .8rem; }
.ai-question-btn { background: transparent; border: 1px solid var(--ai-accent); color: var(--ai-accent); border-radius: 999px; padding: .4rem .9rem; font-size: .8rem; cursor: pointer; transition: background var(--ai-transition); }
.ai-question-btn:hover { background: var(--ai-accent); color: #fff; }
.ai-loading { display: flex; align-items: center; gap: .5rem; color: var(--ai-muted); margin-bottom: 1rem; }
.ai-spinner { width: 14px; height: 14px; border: 2px solid var(--ai-muted); border-top-color: var(--ai-accent); border-radius: 50%; animation: ai-spin .7s linear infinite; }
@keyframes ai-spin { to { transform: rotate(360deg); } }
.ai-error { background: var(--ai-danger); color: #fff; border-radius: var(--ai-radius); padding: .7rem 1rem; margin-bottom: 1rem; }
.ai-suggestions { display: flex; flex-wrap: wrap; gap: .5rem; margin-bottom: 1rem; }
.ai-suggestion-btn { background: var(--ai-bg); border: 1px solid var(--ai-muted); color: var(--ai-text); border-radius: 999px; padding: .4rem .9rem; font-size: .8rem; cursor: pointer; transition: border-color var(--ai-transition); }
.ai-suggestion-btn:hover { border-color: var(--ai-accent); color: var(--ai-accent); }
.ai-input-row { display: flex; gap: .6rem; }
.ai-input { flex: 1; padding: .8rem 1rem; border-radius: var(--ai-radius); border: 1px solid var(--ai-muted); background: var(--ai-bg); color: var(--ai-text); font-size: .95rem; }
.ai-input:focus-visible { outline: 2px solid var(--ai-accent); }

/* ===== États ===== */
.hidden { display: none !important; }

/* ===== Responsive ===== */
@media (max-width: 600px) {
  .ai-hero { flex-direction: column; text-align: center; padding: 2rem 1rem 1.5rem; }
  .ai-hero__cover-img { width: 160px; }
  .ai-auteur__layout { flex-direction: column; align-items: center; text-align: center; }
  .ai-msg-user, .ai-msg-assistant { margin-left: 0; margin-right: 0; }
}