:root {
    --header-gradient-start: #25344A;
    --header-gradient-end: #65748A;
    --sidebar-bg: #f8f9fa;
    --sidebar-item-bg: #ffffff;
    --sidebar-item-hover: #e9ecef;
    --main-bg: #ffffff;
    --text-color: #2C3E50;
    --accent: #18BC9C;
  }
  * {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
  }
  body {
    font-family: 'Montserrat', sans-serif;
    background-color: #f0f2f5;
    color: var(--text-color);
  }
  header {
    background: linear-gradient(135deg, var(--header-gradient-start), var(--header-gradient-end));
    color: #fff;
    padding: 20px 30px;
    box-shadow: 0 4px 6px rgba(0,0,0,0.1);
  }
  .header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
  }
  .header-text {
    flex: 1 1 auto;
  }
  .header-text h1 {
    font-size: 2rem;
    margin-bottom: 10px;
  }
  .header-text p {
    font-size: 1rem;
    opacity: 0.9;
  }
  .logo {
    flex: 0 0 auto;
    max-width: 120px;
    margin-left: 20px;
    text-align: right;
  }
  .logo img {
    width: 100%;
    height: auto;
  }
  /* Bouton pour afficher/cacher la playlist en mobile */
  #menuToggle {
    display: none;
    width: 100%;
    padding: 10px;
    background-color: var(--accent);
    color: #fff;
    border: none;
    font-size: 1rem;
    cursor: pointer;
    border-radius: 5px;
    margin-bottom: 10px;
  }
  .container {
    display: flex;
    flex-wrap: wrap;
    margin: 20px auto;
    max-width: 1200px;
    gap: 20px;
    padding: 0 20px;
  }
  /* Sidebar pour PC : toujours visible */
  #playlistSidebar {
    flex: 1 1 250px;
    background-color: var(--sidebar-bg);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    display: block;
  }
  #playlistSidebar h2 {
    margin-bottom: 20px;
    color: var(--accent);
    font-size: 1.4rem;
  }
  #playlistSidebar ul {
    list-style: none;
  }
  #playlistSidebar li {
    background-color: var(--sidebar-item-bg);
    margin-bottom: 15px;
    padding: 15px;
    border-radius: 8px;
    cursor: pointer;
    transition: background 0.3s, transform 0.3s;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
  }
  #playlistSidebar li:hover {
    background-color: var(--sidebar-item-hover);
    transform: translateX(5px);
  }
  .main-content {
    flex: 3 1 600px;
    background-color: var(--main-bg);
    padding: 20px;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.1);
    display: flex;
    align-items: center;
    justify-content: center;
  }
  .video-wrapper {
    width: 100%;
    max-width: 800px;
    position: relative;
  }
  .video-wrapper video {
    width: 100%;
    border-radius: 10px;
    border: 4px solid var(--accent);
    transition: transform 0.3s;
  }
  .video-wrapper video:hover {
    transform: scale(1.02);
  }
  footer {
    text-align: center;
    padding: 20px;
    background-color: #2C3E50;
    color: white;
    margin-top: 20px;
  }
  /* Responsive : adaptation pour mobile */
  @media (max-width: 768px) {
    .header-container {
      flex-direction: column;
      align-items: center;
    }
    .header-text {
      text-align: center;
    }
    .logo {
      margin: 20px 0 0;
    }
    .container {
      flex-direction: column;
    }
    /* Le bouton de menu s'affiche en mobile */
    #menuToggle {
      display: block;
    }
    /* En mobile, la playlist est cachée par défaut et s'affiche en haut */
    #playlistSidebar {
      width: 100%;
      display: none;
      margin-bottom: 20px;
    }
  }