.spinner {
    border: 6px solid #e3f2fd;
    border-top: 6px solid #1976d2;
    border-radius: 50%;
    width: 48px;
    height: 48px;
    animation: spin 1s linear infinite;
    margin-top: 1em;
}

@keyframes spin {
    0% {
        transform: rotate(0deg);
    }

    100% {
        transform: rotate(360deg);
    }
}
    :root {
      --blue1: #67696e;
      --blue2: #a3aeaf;
      --blue3: #3e4b49;
      --blue4: #000000;
      --sidebar-width: 275px;
      --gradient: linear-gradient(135deg, var(--blue1) 0%, var(--blue3) 100%);
      --glow: 0 0 18px 4px var(--blue3);
      --radius: 18px;
      --transition: 0.28s cubic-bezier(.4,0,.2,1);
    }
    body {
      margin: 0;
      font-family: 'Segoe UI', 'Roboto', Arial, sans-serif;
      background: linear-gradient(115deg, #141e30 68%, #243b55 100%);
      color: #e3f2fd;
      min-height: 100vh;
      display: flex;
      flex-direction: row;
      overflow-x: hidden; /* Prevent horizontal scroll on mobile */
    }
    #sidebar {
      width: var(--sidebar-width);
      background: var(--gradient);
      box-shadow: 0 0 24px 0 #ffffffcc;
      min-height: 100vh;
      padding: 0;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
      position: fixed;
      left: 0;
      top: 0;
      z-index: 20;
    }
    .sidebar-header {
      text-align: center;
      padding: 2.5rem 1rem 1.5rem 1rem;
      font-size: 2.4rem;
      font-weight: 800;
      letter-spacing: .09em;
      color: #fff;
      text-shadow: 0 0 18px var(--blue3), 0 2px 12px #0004;
      user-select: none;
    }
    .sidebar-nav {
      list-style: none;
      margin: 0;
      padding: 0;
    }
    .sidebar-nav li {
      margin: 0.5rem 0;
    }
    .sidebar-link {
      display: flex;
      align-items: center;
      padding: 1rem 2.2rem;
      color: #fff;
      font-size: 1.15rem;
      text-decoration: none;
      border-radius: var(--radius);
      transition: background var(--transition), box-shadow var(--transition), color var(--transition);
      position: relative;
      font-weight: 500;
      cursor: pointer;
      gap: 1rem;
    }
    .sidebar-link:hover, .sidebar-link.active {
      background: #49678acc;
      box-shadow: var(--glow);
      color: #fff;
    }
    .sidebar-footer {
      text-align: center;
      padding: 2rem 1rem;
      font-size: 0.98rem;
      color: #b3e5fc;
      opacity: 0.8;
      user-select: none;
    }
    #main-content {
      margin-left: var(--sidebar-width);
      flex: 1;
      min-width: 0;
      padding: 0;
      display: flex;
      flex-direction: column;
      min-height: 100vh;
      background: transparent;
      transition: background var(--transition);
    }
    .topbar {
      padding: 2rem 2.5rem 1rem 2.5rem;
      display: flex;
      align-items: center;
      gap: 2rem;
      flex-wrap: wrap;
    }
    .search-bar {
      flex: 1;
      position: relative;
      max-width: 400px;
    }
    .search-bar input {
      width: 100%;
      padding: 0.75rem 2.5rem 0.75rem 1rem;
      border-radius: 12px;
      border: none;
      font-size: 1.05rem;
      background: #192742;
      color: #e3f2fd;
      transition: box-shadow var(--transition);
    }
    .search-bar input:focus {
      outline: none;
      box-shadow: var(--glow);
    }
    .search-bar .search-icon {
      position: absolute;
      right: 1.1rem;
      top: 50%;
      transform: translateY(-50%);
      color: #90caf9;
      font-size: 1.35rem;
      pointer-events: none;
    }
    /* Music Cards */
    .music-cards {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
      gap: 2rem;
      margin: 2rem 2.5rem;
    }
    .music-card {
      background: linear-gradient(135deg, #7a7b7c 60%, #f0f2f5 100%);
      border-radius: var(--radius);
      box-shadow: 0 0 24px 0 #ffffffcc;
      overflow: hidden;
      cursor: pointer;
      transition: box-shadow 0.3s, transform 0.2s;
      display: flex;
      flex-direction: column;
      align-items: center;
      padding-bottom: 1rem;
      min-width: 0;
      position: relative;
    }
    .music-card:hover {
      box-shadow: 0 0 36px 8px #ffffffbd;
      transform: translateY(-4px) scale(1.04);
    }
    .music-card-cover img {
      width: 100%;
      height: 160px;
      object-fit: cover;
      border-top-left-radius: var(--radius);
      border-top-right-radius: var(--radius);
      box-shadow: 0 4px 18px #5a050588;
      background: #111;
      display: block;
    }
    .music-card-info {
      text-align: center;
      padding: 1rem 0 0.5rem 0;
      width: 90%;
    }
    .music-card-title {
      font-size: 1.15rem;
      font-weight: 700;
      color: #fff;
      letter-spacing: 0.05em;
      margin-bottom: 0.3em;
      word-break: break-word;
      line-height: 1.18;
      text-shadow: 0 1px 8px #5a050588;
    }
    .music-card-artist {
      font-size: 1rem;
      color: #c5e1facc;
      font-weight: 500;
    }
    .music-card-album {
      font-size: 0.9rem;
      color: #bbdefbcc;
      margin-top: 0.15em;
    }
    .music-card-actions {
      margin-top: 0.7em;
      display: flex;
      gap: 1.2em;
      justify-content: center;
      align-items: center;
    }
    .music-card-btn {
      background: #464d53;
      color: #e6e0e0;
      border: none;
      border-radius: 8px;
      padding: 0.5em 0.9em;
      font-size: 1rem;
      cursor: pointer;
      box-shadow: 0 0 8px 0 #64b5f6bb;
      transition: background var(--transition), box-shadow var(--transition), transform 0.18s;
      display: flex;
      align-items: center;
      gap: 0.5em;
    }
    .music-card-btn:hover {
      background: #464d53;
      box-shadow: 0 0 16px 2px #5a050588;
      transform: scale(1.07);
    }
    /* Audio Player */
    #audio-player-bar {
      position: fixed;
      bottom: 0;
      left: var(--sidebar-width);
      right: 0;
      background: #192742;
      box-shadow: 0 -6px 24px 0 #ffffffcc;
      display: flex;
      align-items: center;
      gap: 2.2rem;
      padding: 1.2rem 2.5rem;
      z-index: 11;
      transition: left var(--transition);
    }
    .player-cover {
      width: 58px;
      height: 58px;
      border-radius: 12px;
      overflow: hidden;
      box-shadow: 0 0 12px 0 #ffffff88;
    }
    .player-cover img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      background: #111;
      display: block;
    }
    .player-info {
      min-width: 120px;
      display: flex;
      flex-direction: column;
      gap: 2px;
      color: #fff;
    }
    .player-title {
      font-size: 1.12rem;
      font-weight: 700;
      letter-spacing: .04em;
      margin-bottom: 0.1em;
      text-shadow: 0 1px 8px #1976d288;
    }
    .player-artist {
      font-size: 0.99rem;
      color: #90caf9;
      font-weight: 500;
    }
    .player-controls {
      display: flex;
      gap: 1.3em;
      align-items: center;
      margin-left: 2em;
    }
    .player-btn {
      background: none;
      border: none;
      color: #64b5f6;
      font-size: 1.35rem;
      cursor: pointer;
      padding: 0.5em;
      border-radius: 50%;
      transition: background var(--transition), color var(--transition), box-shadow var(--transition), transform 0.16s;
    }
    .player-btn:active, .player-btn:hover {
      background: #1565c0;
      color: #fff;
      box-shadow: 0 0 8px 2px #1976d2cc;
      transform: scale(1.16);
    }
    .player-progress {
      flex: 1;
      margin: 0 1.2em;
      display: flex;
      align-items: center;
      gap: 0.7em;
      color: #90caf9;
      min-width: 100px;
    }
    .progress-bar {
      width: 100%;
      background: #111;
      height: 6px;
      border-radius: 6px;
      overflow: hidden;
      cursor: pointer;
      margin: 0 0.4em;
    }
    .progress-bar-inner {
      background: var(--gradient);
      height: 100%;
      width: 0%;
      transition: width 0.18s;
    }
    .player-volume {
      display: flex;
      align-items: center;
      gap: 0.5em;
      margin-left: 1em;
    }
    .player-volume input[type=range] {
      width: 78px;
      accent-color: #2196f3;
    }
    /* Settings Panel */
    #settings-panel {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100vw;
      height: 100vh;
      background: #141e3088;
      z-index: 30;
      align-items: center;
      justify-content: center;
    }
    .settings-box {
      background: var(--gradient);
      padding: 2.3rem 2.3rem 2rem 2.3rem;
      border-radius: var(--radius);
      box-shadow: 0 0 42px 0 #2196f3cc;
      min-width: 320px;
      width: 96vw;
      max-width: 390px;
      color: #fff;
      position: relative;
    }
    .settings-title {
      font-size: 1.3rem;
      font-weight: bold;
      margin-bottom: 1.1em;
      text-align: center;
      letter-spacing: 0.05em;
      text-shadow: 0 0 8px #1976d288;
    }
    .settings-row {
      margin-bottom: 1.3em;
      display: flex;
      flex-direction: column;
      gap: 0.3em;
    }
    .settings-label {
      font-size: 1.06rem;
      font-weight: 500;
      margin-bottom: 0.2em;
    }
    .settings-select, .settings-input {
      padding: 0.5em 0.7em;
      border-radius: 7px;
      border: none;
      font-size: 1rem;
      background: #192742;
      color: #fff;
      margin-top: 0.2em;
    }
    .settings-btn-row {
      display: flex;
      justify-content: flex-end;
      gap: 1em;
      margin-top: 1.5em;
    }
    .settings-btn {
      background: #1565c0;
      color: #fff;
      border: none;
      border-radius: 8px;
      padding: 0.5em 1.2em;
      font-size: 1rem;
      cursor: pointer;
      box-shadow: 0 0 8px 0 #64b5f6bb;
      transition: background var(--transition), box-shadow var(--transition), transform 0.18s;
    }
    .settings-btn:hover {
      background: #1e88e5;
      box-shadow: 0 0 16px 2px #64b5f6cc;
      transform: scale(1.07);
    }
    .settings-close {
      position: absolute;
      top: 0.9em;
      right: 1em;
      font-size: 1.3em;
      background: none;
      border: none;
      color: #fff;
      cursor: pointer;
      transition: color var(--transition), transform 0.18s;
    }
    .settings-close:hover {
      color: #bbdefb;
      transform: scale(1.16);
    }
    /* Responsive */
    @media screen and (max-width: 950px) {
      #sidebar {
        width: 70px;
        min-width: 70px;
      }
      .sidebar-header {
        font-size: 1.5rem;
        padding: 1.2rem 0.5rem 1rem 0.5rem;
      }
      .sidebar-link {
        padding: 0.7rem 1rem;
        font-size: 1rem;
        gap: 0.7rem;
        justify-content: center;
      }
      #main-content {
        margin-left: 70px;
      }
      #audio-player-bar {
        left: 70px;
        padding: 0.7rem 1rem;
      }
      .topbar {
        padding: 1.2rem 1rem 0.7rem 1rem;
        gap: 1rem;
      }
      .music-cards {
        margin: 1.2rem 1rem;
        gap: 1.2rem;
      }
    }
    @media screen and (max-width: 600px) {
      #sidebar {
        position: fixed;
        width: 54px;
        min-width: 54px;
        padding: 0;
      }
      .sidebar-header {
        font-size: 1rem;
        padding: 0.7rem 0.2rem 0.7rem 0.2rem;
      }
      .sidebar-link {
        padding: 0.4rem 0.3rem;
        font-size: 0.84rem;
        gap: 0.4rem;
        justify-content: center;
      }
      #main-content {
        margin-left: 54px;
      }
      #audio-player-bar {
        left: 54px;
        padding: 0.5rem 0.2rem;
      }
      .topbar {
        padding: 0.6rem 0.3rem 0.3rem 0.3rem;
        gap: 0.5rem;
      }
      .music-cards {
        margin: 0.6rem 0.3rem;
        gap: 0.7rem;
      }
      .settings-box {
        min-width: 0;
        width: 96vw;
        padding: 1rem 0.7rem 1rem 0.7rem;
      }
      .music-card {
        padding-bottom: 0.5rem;
        min-width: 0;
        max-width: 180px;
        margin: 0 auto;
      }
      .music-card-cover img {
        height: 100px;
      }
      .music-card-info {
        padding: 0.5rem 0 0.3rem 0;
        width: 98%;
      }
      .music-card-title {
        font-size: 0.95rem;
      }
      .music-card-artist {
        font-size: 0.85rem;
      }
      .music-card-album {
        font-size: 0.8rem;
      }
      .music-card-actions {
        gap: 0.6em;
        margin-top: 0.4em;
      }
      .music-card-btn {
        font-size: 0.85rem;
        padding: 0.3em 0.5em;
      }
    }