:root {
  --primary-color: #004080;
  --secondary-color: #3498db;
  --light-color: #e6f2ff;
  --dark-color: #2c3e50;
  --success-color: #27ae60;
  --danger-color: #e74c3c;
  --warning-color: #f5c518;
  --shadow: 0 6px 18px rgba(0, 0, 0, 0.1);
  --border-radius: 12px;
  --transition: all 0.3s ease;
}

/* Style global */
body {
  font-family: "Segoe UI", Roboto, Arial, sans-serif;
  font-size: 16px;
  background: linear-gradient(to bottom, var(--light-color), #ffffff);
  color: var(--dark-color);
  margin: 0;
  padding: 20px;
  line-height: 1.6;
}

/* Bandeau d’en-tête */
header {
  background: var(--primary-color);
  color: #fff;
  padding: 20px;
  text-align: center;
  border-radius: var(--border-radius);
  margin-bottom: 30px;
  box-shadow: var(--shadow);
}

header h1 {
  margin: 0;
  font-size: 28px;
  letter-spacing: 1px;
}

/* Conteneur principal */
.container {
  max-width: 950px;
  margin: 0 auto;
  background: #fff;
  padding: 25px 30px;
  border-radius: var(--border-radius);
  box-shadow: var(--shadow);
}

/* Titres */
h2 {
  font-size: 20px;
  border-left: 6px solid var(--secondary-color);
  padding-left: 12px;
  margin-top: 25px;
  margin-bottom: 15px;
  color: var(--primary-color);
}

/* Formulaire */
form {
  margin: 20px 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 15px;
}

form label {
  font-weight: 600;
  color: var(--primary-color);
}

form select,
form input[type="text"],
form input[type="submit"] {
  padding: 10px 12px;
  border: 1px solid #ccddee;
  border-radius: 6px;
  outline: none;
  font-size: 15px;
  background: #f9fcff;
  transition: var(--transition);
}

form select:focus,
form input[type="text"]:focus {
  border-color: var(--secondary-color);
  box-shadow: 0 0 5px rgba(52, 152, 219, 0.5);
}

form input[type="submit"] {
  background: var(--secondary-color);
  color: #fff;
  cursor: pointer;
  transition: var(--transition);
  border: none;
}

form input[type="submit"]:hover {
  background: #2c80c9;
  transform: scale(1.03);
}

/* Résultats */
.result-block {
  margin-top: 30px;
  padding: 20px;
  background: #f0f8ff;
  border-left: 6px solid var(--secondary-color);
  border-radius: 8px;
  box-shadow: inset 0 0 10px rgba(0, 64, 128, 0.05);
}

.result-block b {
  color: var(--primary-color);
}

/* Messages */
.red {
  color: var(--danger-color);
  font-weight: bold;
}

.notice {
  background: #fff6e6;
  border: 1px solid var(--warning-color);
  padding: 12px;
  border-radius: 6px;
  color: #8a6d3b;
  margin: 15px 0;
  font-style: italic;
}

/* Tableau */
table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 15px;
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

table th,
table td {
  border: 1px solid #ddd;
  padding: 10px;
  text-align: center;
}

table th {
  background: var(--primary-color);
  color: #fff;
  font-weight: 500;
}

/* Footer */
footer {
  margin-top: 30px;
  text-align: center;
  font-size: 14px;
  color: #555;
}

/* Bouton retour en haut */
.scrollToTopBtn {
  position: fixed !important;
  bottom: 30px !important;
  right: 30px !important;
  background: none;
  border: none;
  cursor: pointer;
  z-index: 9999;
  opacity: 0;
  transform: translateY(100px);
  transition: all 0.4s ease;
}

.scrollToTopBtn img {
  width: 60px; /* Taille icone */
  height: 60px;
  object-fit: contain;
  opacity: 0.9;
  transition:
    transform 0.3s ease,
    opacity 0.3s ease;
}

.scrollToTopBtn.showBtn {
  opacity: 1;
  transform: translateY(0);
}

.scrollToTopBtn:hover img {
  transform: translateY(-4px) scale(1.05);
  opacity: 1;
}

/* ---- Tooltip CSS ---- */
.scrollToTopBtn::after {
  content: attr(data-tooltip);
  position: absolute;
  bottom: 80px; /* distance au-dessus du bouton */
  right: 0;
  left: auto;
  background: rgba(0, 0, 0, 0.8);
  color: white;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 14px;
  white-space: nowrap;
  opacity: 0;
  transform: translateY(10px);
  pointer-events: none;
  transition:
    opacity 0.3s ease,
    transform 0.3s ease;
}

.scrollToTopBtn:hover::after {
  opacity: 1;
  transform: translateY(0);
}

/* Effet de zoom/soulèvement sur le bouton de retour */
.backBtn img {
  transition:
    opacity 0.3s ease,
    transform 0.3s ease;
  display: inline-block;
}

.backBtn:hover img {
  transform: translateY(-3px) scale(1.20);
  
}

/* Responsive */
@media (max-width: 768px) {
  .container {
    padding: 15px;
  }

  form {
    flex-direction: column;
    align-items: stretch;
  }

  form select,
  form input[type="text"],
  form input[type="submit"] {
    width: 100%;
  }
}