:root {
  --dk-primary: #0f2d3a; /* Navy foncé Dakitrack */
  --dk-primary-700: #163d4e;
  --dk-primary-600: #19485c;
  --dk-accent: #c77057;  /* Terre cuivrée Dakitrack */
  --dk-accent-600: #b85f48;
  --dk-bg: #f6f8fa;
  --dk-card: #ffffff;
  --dk-border: #e6eaee;
  --dk-text: #0f2430;
  --dk-text-muted: #6b7b88;
  --radius-lg: 18px;
  --radius-md: 14px;
  --radius-sm: 10px;
  --shadow-sm: 0 2px 10px rgba(15,45,58,.06);
  --shadow-md: 0 10px 30px rgba(15,45,58,.10);
  --shadow-lg: 0 24px 60px rgba(15,45,58,.14);
}

/* Reset d'arrière-plan et typographie */
body {
  background: radial-gradient(1200px 600px at 10% -10%, rgba(199,112,87,.14), transparent 60%),
              radial-gradient(1200px 600px at 110% 10%, rgba(15,45,58,.12), transparent 60%),
              var(--dk-bg) !important;
  color: var(--dk-text);
  font-family: 'Inter', system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif !important;
}

.container {
  background: var(--dk-card) !important;
  border-radius: 24px !important;
  box-shadow: var(--shadow-lg) !important;
}

/* Header marque Dakitrack */
.header {
  background: linear-gradient(135deg, var(--dk-primary) 0%, var(--dk-primary-700) 100%) !important;
  position: relative;
  padding: 22px 28px !important;
}

.header .brand {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
}

.brand-mark {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--dk-accent);
  position: relative;
  box-shadow: inset 0 -4px 10px rgba(0,0,0,.12);
}

.brand-mark::before,
.brand-mark::after {
  content: '';
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  width: 34px;
  height: 34px;
  border-top: 4px solid var(--dk-accent);
  border-radius: 50%;
  top: -22px;
}

.brand-mark::after {
  width: 48px;
  height: 48px;
  top: -36px;
  border-top-width: 4px;
  opacity: .9;
}

.header h1 {
  font-weight: 800;
  letter-spacing: .2px;
}

/* Sous-entête du chat */
.chat-header {
  background: linear-gradient(180deg, rgba(15,45,58,.96), rgba(15,45,58,.92)) !important;
  border-bottom: 1px solid rgba(255,255,255,.08) !important;
}

.chat-status { color: rgba(255,255,255,.8) !important; }

/* Zone messages */
.chat-messages {
  background: linear-gradient(180deg, #fff, #fbfcfe) !important;
  border-bottom: 1px solid var(--dk-border) !important;
}

.message-avatar {
  background: var(--dk-primary) !important;
  color: #fff !important;
  box-shadow: var(--shadow-sm);
}

.message.assistant .message-content {
  background: #f1f4f8 !important;
  color: var(--dk-text) !important;
  border: 1px solid var(--dk-border) !important;
  border-bottom-left-radius: 12px !important;
  border-top-left-radius: var(--radius-md) !important;
  border-top-right-radius: var(--radius-md) !important;
}

.message.user .message-content {
  background: linear-gradient(135deg, var(--dk-accent) 0%, var(--dk-accent-600) 100%) !important;
  border: none !important;
  box-shadow: 0 10px 24px rgba(199,112,87,.25);
}

/* Input et bouton d'envoi */
.chat-input-container { background: var(--dk-card) !important; }

.chat-input {
  border: 2px solid var(--dk-border) !important;
  background: #fff !important;
  border-radius: 16px !important;
}

.chat-input:focus {
  border-color: var(--dk-accent) !important;
  box-shadow: 0 0 0 4px rgba(199,112,87,.12) !important;
}

.chat-send {
  width: 54px !important;
  height: 54px !important;
  border-radius: 16px !important;
  background: linear-gradient(135deg, var(--dk-accent) 0%, var(--dk-accent-600) 100%) !important;
  box-shadow: 0 10px 22px rgba(199,112,87,.35) !important;
}

.chat-send:hover { transform: translateY(-1px) scale(1.03) !important; }

/* Cartes de données (résumés, listes) */
.response-card {
  background: #fff;
  border: 1px solid var(--dk-border);
  border-radius: 16px;
  box-shadow: var(--shadow-sm);
  padding: 14px 16px;
}

/* Barre d’actions en tête (optionnelle si présente) */
.header-actions .btn {
  background: rgba(255,255,255,.1);
  color: #fff;
  border: 1px solid rgba(255,255,255,.18);
  padding: 8px 14px;
  border-radius: 12px;
  transition: all .2s ease;
}

.header-actions .btn:hover { background: rgba(255,255,255,.16); transform: translateY(-1px); }

/* Toggle dark (préparé) */
@media (prefers-color-scheme: dark) {
  body { background: #0b1921; }
  .chat-messages { background: #0e1f28 !important; }
}