/* eConvertir.com - CSS optimisé pour performance et mobile-first */
/* Couleurs françaises: Bleu (#0055A4), Blanc (#FFFFFF), Rouge (#EF4135) */

:root {
  --bleu-france: #0055A4;
  --blanc: #FFFFFF;
  --rouge-france: #EF4135;
  --gris-clair: #F5F5F5;
  --gris-moyen: #E0E0E0;
  --gris-fonce: #333333;
  --texte-principal: #1A1A1A;
  --texte-secondaire: #666666;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: var(--texte-principal);
  background-color: var(--blanc);
}

/* Header */
header {
  background: linear-gradient(135deg, var(--bleu-france) 0%, #003d7a 100%);
  color: var(--blanc);
  padding: 1rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}

header nav {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0;
}

header h1 a {
  color: var(--blanc);
  text-decoration: none;
}

header .nav-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-top: 0.5rem;
}

header .nav-links a {
  color: var(--blanc);
  text-decoration: none;
  font-size: 0.9rem;
  padding: 0.25rem 0.5rem;
  border-radius: 4px;
  transition: background-color 0.2s;
}

header .nav-links a:hover {
  background-color: rgba(255,255,255,0.2);
}

/* Main Container */
main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1rem;
}

/* Hero Section */
.hero {
  text-align: center;
  padding: 2rem 1rem;
  background: linear-gradient(to bottom, var(--gris-clair) 0%, var(--blanc) 100%);
  border-radius: 8px;
  margin-bottom: 2rem;
}

.hero h1 {
  font-size: 2rem;
  color: var(--bleu-france);
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.1rem;
  color: var(--texte-secondaire);
  max-width: 700px;
  margin: 0 auto;
}

/* Converter Grid */
.converter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-bottom: 3rem;
}

.converter-card {
  background: var(--blanc);
  border: 2px solid var(--gris-moyen);
  border-radius: 8px;
  padding: 1.5rem;
  text-decoration: none;
  color: var(--texte-principal);
  transition: all 0.3s ease;
  box-shadow: 0 2px 4px rgba(0,0,0,0.05);
}

.converter-card:hover {
  border-color: var(--bleu-france);
  box-shadow: 0 4px 12px rgba(0,85,164,0.15);
  transform: translateY(-2px);
}

.converter-card h3 {
  color: var(--bleu-france);
  font-size: 1.3rem;
  margin-bottom: 0.5rem;
}

.converter-card p {
  color: var(--texte-secondaire);
  font-size: 0.95rem;
}

/* Converter Page */
.converter-container {
  background: var(--blanc);
  border: 2px solid var(--gris-moyen);
  border-radius: 8px;
  padding: 2rem;
  margin-bottom: 2rem;
  box-shadow: 0 4px 12px rgba(0,0,0,0.08);
}

.converter-container h1 {
  color: var(--bleu-france);
  font-size: 2rem;
  margin-bottom: 1.5rem;
  text-align: center;
}

.converter-form {
  display: grid;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.input-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.input-group label {
  font-weight: 600;
  color: var(--texte-principal);
  font-size: 0.95rem;
}

.input-row {
  display: flex;
  gap: 0.5rem;
}

.input-group input {
  flex: 1;
  padding: 0.75rem;
  border: 2px solid var(--gris-moyen);
  border-radius: 6px;
  font-size: 1rem;
  transition: border-color 0.2s;
}

.input-group input:focus {
  outline: none;
  border-color: var(--bleu-france);
}

.input-group select {
  flex: 1;
  padding: 0.75rem;
  border: 2px solid var(--gris-moyen);
  border-radius: 6px;
  font-size: 1rem;
  background-color: var(--blanc);
  cursor: pointer;
  transition: border-color 0.2s;
}

.input-group select:focus {
  outline: none;
  border-color: var(--bleu-france);
}

.swap-btn {
  background: var(--bleu-france);
  color: var(--blanc);
  border: none;
  border-radius: 6px;
  padding: 0.5rem 1rem;
  cursor: pointer;
  font-size: 1.2rem;
  transition: background-color 0.2s;
  align-self: center;
}

.swap-btn:hover {
  background: #003d7a;
}

/* Content Section */
.content-section {
  background: var(--gris-clair);
  border-radius: 8px;
  padding: 2rem;
  margin-bottom: 2rem;
}

.content-section h2 {
  color: var(--bleu-france);
  font-size: 1.6rem;
  margin-bottom: 1rem;
  border-left: 4px solid var(--rouge-france);
  padding-left: 1rem;
}

.content-section h3 {
  color: var(--texte-principal);
  font-size: 1.3rem;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

.content-section p {
  margin-bottom: 1rem;
  line-height: 1.8;
}

.content-section ul, .content-section ol {
  margin-left: 2rem;
  margin-bottom: 1rem;
}

.content-section li {
  margin-bottom: 0.5rem;
  line-height: 1.8;
}

.conversion-table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  background: var(--blanc);
  border-radius: 8px;
  overflow: hidden;
}

.conversion-table th {
  background: var(--bleu-france);
  color: var(--blanc);
  padding: 0.75rem;
  text-align: left;
  font-weight: 600;
}

.conversion-table td {
  padding: 0.75rem;
  border-bottom: 1px solid var(--gris-moyen);
}

.conversion-table tr:last-child td {
  border-bottom: none;
}

.conversion-table tr:nth-child(even) {
  background-color: var(--gris-clair);
}

/* Footer */
footer {
  background: var(--gris-fonce);
  color: var(--blanc);
  padding: 2rem 1rem;
  margin-top: 3rem;
}

footer .footer-content {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
}

footer h3 {
  color: var(--blanc);
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

footer ul {
  list-style: none;
}

footer ul li {
  margin-bottom: 0.5rem;
}

footer a {
  color: var(--gris-moyen);
  text-decoration: none;
  transition: color 0.2s;
}

footer a:hover {
  color: var(--blanc);
}

footer .copyright {
  text-align: center;
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid rgba(255,255,255,0.1);
  color: var(--gris-moyen);
}

/* Responsive Design - Tablet */
@media (min-width: 768px) {
  header h1 {
    font-size: 1.8rem;
  }

  header .nav-links {
    margin-top: 0;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .converter-grid {
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  }

  .converter-form {
    grid-template-columns: 1fr auto 1fr;
    align-items: end;
  }
}

/* Responsive Design - Desktop */
@media (min-width: 1024px) {
  header h1 {
    font-size: 2rem;
  }

  .hero h1 {
    font-size: 3rem;
  }

  main {
    padding: 2rem;
  }
}

/* Print Styles */
@media print {
  header, footer, .nav-links {
    display: none;
  }
}

/* Performance Optimizations */
img {
  max-width: 100%;
  height: auto;
}

.lazy {
  opacity: 0;
  transition: opacity 0.3s;
}

.lazy.loaded {
  opacity: 1;
}