/* ===========================
   RESET & BASE
=========================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  background: #0d0d0d;
  color: #f0f0f0;
  font-family: 'DM Sans', sans-serif;
  min-height: 100vh;
}

/* ===========================
   HEADER
=========================== */
header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 1rem;
  padding: 3rem 4rem 2rem;
  border-bottom: 1px solid #2a2a2a;
}

header h1 {
  font-family: 'Bebas Neue', sans-serif;
  font-size: clamp(2.5rem, 5vw, 4rem);
  letter-spacing: 0.03em;
  line-height: 1;
}

header p {
  color: #888;
  font-size: 0.95rem;
  margin-top: 0.4rem;
}

/* ===========================
   FILTRES
=========================== */
.filters {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.filter-btn {
  background: #1e1e1e;
  border: 1px solid #333;
  color: #888;
  padding: 0.4rem 1rem;
  border-radius: 999px;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  cursor: pointer;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.filter-btn:hover,
.filter-btn.active {
  background: #fff;
  color: #000;
  border-color: #fff;
}

/* ===========================
   SECTIONS SEMESTRE
=========================== */
.semestre {
  padding: 3rem 4rem;
  max-width: 1400px;
  margin: 0 auto;
}

/* Titre de section + ligne */
.semestre-header {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-bottom: 2rem;
}

.semestre-header h2 {
  font-family: 'Bebas Neue', sans-serif;
  font-size: 1.8rem;
  letter-spacing: 0.06em;
  color: #f0f0f0;
  white-space: nowrap;
}

.semestre-line {
  flex: 1;
  height: 1px;
  background: #2a2a2a;
}

/* ===========================
   GRILLE DE CARTES
=========================== */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(460px, 1fr));
  gap: 2rem;
}

/* ===========================
   CARTE
=========================== */
.card {
  background: #111;
  border: 1px solid #2a2a2a;
  border-radius: 4px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform 0.25s, border-color 0.25s;
}

.card:hover {
  transform: translateY(-4px);
  border-color: #444;
}

/* --- Zone image --- */
.card-image {
  position: relative;
  aspect-ratio: 16 / 9;
  overflow: hidden;
  background: #1a1a1a;
}

.card-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transition: transform 0.4s;
}

.card:hover .card-image img {
  transform: scale(1.04);
}

/* Placeholder gris quand pas d'image */
.placeholder {
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, #1c1c1c, #2a2a2a);
}

/* Badge "PDF Disponible" */
.badge-pdf {
  position: absolute;
  top: 12px;
  left: 12px;
  background: rgba(0, 0, 0, 0.7);
  color: #fff;
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 5px 10px;
  border-radius: 2px;
  border: 1px solid rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(4px);
}

/* Titre sur l'image en bas */
.image-title {
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 2.5rem 1.5rem 1.2rem;
  background: linear-gradient(to top, rgba(0,0,0,0.85), transparent);
  font-family: 'Bebas Neue', sans-serif;
  font-size: clamp(1.2rem, 2vw, 1.7rem);
  letter-spacing: 0.04em;
  color: #fff;
  text-transform: uppercase;
  line-height: 1.1;
}

/* --- Corps de la carte --- */
.card-body {
  padding: 1.25rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
  flex: 1;
}

.card-top-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.tag {
  background: #1e1e1e;
  border: 1px solid #333;
  color: #888;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 4px 10px;
  border-radius: 2px;
}

.year {
  color: #888;
  font-size: 0.8rem;
  white-space: nowrap;
}

.card-title {
  font-size: 1.1rem;
  font-weight: 600;
  color: #f0f0f0;
  line-height: 1.3;
}

.card-desc {
  color: #888;
  font-size: 0.88rem;
  line-height: 1.6;
  flex: 1;
}

/* --- Pied de carte --- */
.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 0.75rem;
  border-top: 1px solid #2a2a2a;
  margin-top: 0.25rem;
  gap: 1rem;
}

.prof {
  color: #666;
  font-size: 0.82rem;
}

.btn {
  display: inline-block;
  background: transparent;
  border: 1px solid #444;
  color: #f0f0f0;
  font-family: 'DM Sans', sans-serif;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0.5rem 1rem;
  border-radius: 2px;
  text-decoration: none;
  white-space: nowrap;
  transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.btn:hover {
  background: #fff;
  color: #000;
  border-color: #fff;
}

/* ===========================
   RESPONSIVE
=========================== */
@media (max-width: 700px) {
  header {
    padding: 2rem 1.5rem;
  }

  .semestre {
    padding: 2rem 1.5rem;
  }

  .grid {
    grid-template-columns: 1fr;
  }
}