body {
    background-color: #21224e;
}

.intro {
    margin: 2rem 4rem 1rem 4rem;
    padding: 0.5rem 2rem 0.5rem 2rem;
    text-align: center;
    background-color: #21224e;
    border-radius: 1rem;
}

/* Variables partagées par la conférence à la une et les cartes */
.featured-conf,
.past-confs {
    --conf-accent: #f5b942;
    --conf-bg: #14182b;
    --conf-text: #eef0f7;
    --conf-muted: #b4b9cf;
}

/* ===== Conférence à la une ===== */
.featured-conf {
    display: grid;
    grid-template-columns: minmax(0, 2fr) minmax(0, 3fr);
    gap: 2rem;
    align-items: center;
    max-width: 1000px;
    margin: 2rem auto;
    padding: 1.5rem;
    background: var(--conf-bg);
    color: var(--conf-text);
    border-radius: 16px;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.25);
}

.featured-conf-poster { margin: 0; }

.featured-conf-poster img {
    display: block;
    width: 100%;
    height: auto;
    border-radius: 10px;
}

.conf-badge {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    margin-bottom: 0.8rem;
    border-radius: 999px;
    background: var(--conf-accent);
    color: #1a1a1a;
    font-size: 0.8rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.conf-badge-past {
    background: transparent;
    border: 1px solid var(--conf-muted);
    color: var(--conf-muted);
}

.featured-conf-body h3 {
    margin: 0 0 0.3rem;
    font-size: clamp(1.4rem, 2.5vw, 2rem);
    line-height: 1.2;
}

.conf-speaker {
    margin: 0 0 0.8rem;
    color: var(--conf-muted);
    font-size: 1.1rem;
}

.conf-date {
    margin: 0 0 1.2rem;
    font-weight: 600;
    color: var(--conf-accent);
}

.conf-date::before { content: "📅 "; }

.conf-summary {
    margin: 0 0 1.5rem;
    line-height: 1.7;
    max-width: 60ch;
}

.conf-button {
    display: inline-block;
    padding: 0.7rem 1.4rem;
    border-radius: 8px;
    background: var(--conf-accent);
    color: #1a1a1a;
    font-weight: 700;
    text-decoration: none;
    transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.conf-button:hover,
.conf-button:focus-visible {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.3);
}

/* ===== Anciennes conférences ===== */
.past-confs {
    max-width: 1000px;
    margin: 3rem auto;
    padding: 0 1rem;
}

.past-confs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.conf-card {
    display: flex;
    flex-direction: column;
    background: var(--conf-bg);
    color: var(--conf-text);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.2);
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.conf-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.3);
}

.conf-card-poster {
    width: 100%;
    aspect-ratio: 4 / 3;
    object-fit: contain;         /* évite de couper le texte des affiches */
    background: #0b0e1c;
}

.conf-card-body {
    display: flex;
    flex-direction: column;
    flex: 1;
    padding: 1rem 1.2rem 1.2rem;
}

.conf-card-date {
    color: var(--conf-accent);
    font-size: 0.85rem;
    font-weight: 600;
}

.conf-card-body h3 {
    margin: 0.3rem 0;
    font-size: 1.1rem;
    line-height: 1.3;
}

.conf-card-speaker {
    margin: 0 0 0.8rem;
    color: var(--conf-muted);
}

.conf-card-summary {
    margin: 0 0 1rem;
    font-size: 0.95rem;
    line-height: 1.6;
    display: -webkit-box;
    -webkit-line-clamp: 4;
    line-clamp: 4;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.conf-card-link {
    margin-top: auto;            /* colle le lien en bas de la carte */
    color: var(--conf-accent);
    font-weight: 700;
    text-decoration: none;
}

.conf-card-link:hover,
.conf-card-link:focus-visible {
    text-decoration: underline;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip: rect(0 0 0 0);
    white-space: nowrap;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .intro {
        margin: 2rem 1.5rem 1rem 1.5rem;
        padding: 0.5rem 1.5rem;
        text-align: justify;
    }
}

@media (max-width: 720px) {
    .featured-conf {
        grid-template-columns: 1fr;
        padding: 1rem;
        border-radius: 0;
    }
    .featured-conf-poster {
        max-width: 360px;
        margin: 0 auto;
    }
}

/* ===== Fond étoilé animé ===== */
@keyframes twinkling {
    0% { opacity: 0.3; }
    50% { opacity: 1; }
    100% { opacity: 0.3; }
}

.stars {
    position: fixed;
    width: 100%;
    height: 100%;
    background: transparent;
    overflow: hidden;
    top: 0;
    left: 0;
    z-index: -1;
}

.star {
    position: absolute;
    width: 3px;
    height: 3px;
    background: white;
    border-radius: 50%;
    opacity: 0.3;
    animation: twinkling 1.5s infinite alternate ease-in-out;
}

.star:nth-child(even) {
    animation-duration: 2.5s;
}

  /* 🔹 Lightbox (Mode plein écran) */
.lightbox {
  display: none; /* Caché par défaut */
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  justify-content: center;
  align-items: center;
  z-index: 1000;
}

.lightbox-content {
  max-width: 90%;
  max-height: 90%;
  box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.2);
  transition: transform 0.3s ease-in-out;
}

/* 🔹 Effet de fermeture */
.close {
  position: absolute;
  top: 15px;
  right: 25px;
  color: white;
  font-size: 30px;
  font-weight: bold;
  cursor: pointer;
}

/* 🔹 Animation d'apparition */
.lightbox.show {
  display: flex;
  animation: fadeIn 0.3s;
}