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

    .tools-section {

      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);

      padding: 30px;

      border-radius: 12px;

    }

    .tool-link {

      display: flex;

      flex-direction: column;

      background: white;

      padding: 20px;

      border-radius: 10px;

      text-decoration: none;

      color: #333;

      transition: all 0.3s ease;

      height: 100%;

    }



    .tool-link:hover {

      transform: translateY(-5px);

      box-shadow: 0 8px 25px rgba(0, 0, 0, 0.2);

    }



    .tool-link i {

      color: #667eea;

      margin-right: 15px;

      font-size: 24px;

      width: 30px;

      text-align: center;

    }



    .tool-link-content {
      display: flex;
      align-items: flex-start;
    }

    .tool-link-text {
      flex-grow: 1;
    }

    .tool-link span {
      font-size: 18px;
      font-weight: 600;
    }

    .tool-link small {
      display: block;
      color: #666;
      margin-top: 5px;
      line-height: 1.4;
    }

    .course-grid {

      display: grid;

      grid-template-columns: 1fr 1fr;

      gap: 20px;

    }

    .tools-section h3 {

      color: white;
      font-size: 24px;

      margin-bottom: 25px;
      text-align: center;

    }

    .syllabus-table-wrapper {
      overflow-x: auto;
    }

    .syllabus-table {

      width: 100%;

      border-collapse: collapse;

      font-size: 14px;

      border: 1px solid #e0e0e0;

      border-radius: 8px;

      overflow: hidden;

    }

    .syllabus-table th,
    .syllabus-table td {

      padding: 12px 15px;

      text-align: left;

      border-bottom: 1px solid #e0e0e0;

    }

    .syllabus-table thead th {

      background-color: #f8f9fa;

      color: #333;

      font-weight: 600;

      border-bottom-width: 2px;

    }

    .syllabus-table tbody tr:last-child td {
      border-bottom: 0;
    }

    .syllabus-table tbody tr:hover {
      background-color: #f9f9fb;
    }



    .syllabus-table td:nth-child(1) {

      font-weight: 600;

      color: #667eea;

      width: 15%;

    }

    .syllabus-table td:nth-child(1) a {

      text-decoration: none;

      color: #667eea;

      display: block;

    }

    .syllabus-table td:nth-child(1) a:hover {
      text-decoration: underline;
    }



    .syllabus-table td:nth-child(2) {

      font-weight: 600;

      color: #333;

      width: 25%;

    }

    .syllabus-table td:nth-child(3) {

      color: #555;

      line-height: 1.5;

    }



    .syllabus-table .vize-haftasi td {

      background-color: #FFFBEB;

      color: #B45309;

      font-weight: 700;

      text-align: center;

      font-size: 15px;

    }

    .syllabus-table .final-haftasi td {

      background-color: #FEF2F2;

      color: #B91C1C;

      font-weight: 700;

      text-align: center;

      font-size: 15px;

    }

    .pdf-viewer-container {
      position: relative;
      width: 100%;
      height: 700px;
      border-radius: 12px;
      overflow: hidden;
      background: #f0f0f0;
      border: 1px solid #ddd;
      box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
      margin-bottom: 15px;
    }

    .index_content {
      flex-grow: 1;
      min-width: 0;
    }

    .index_content h2 {
      font-size: 24px;
      color: #333;
      margin-bottom: 20px;
    }

    .index_content p {
      font-size: 16px;
      line-height: 1.7;
      color: #555;
      margin-bottom: 15px;
    }

    .index_content ul {
      list-style-type: disc;
      margin-left: 20px;
      padding-left: 10px;
      color: #555;
      margin-bottom: 20px;
    }

    .index_content li {
      margin-bottom: 10px;
      line-height: 1.6;
    }

    .lesson-unpublished {
      padding: 30px;
      background-color: #fff3cd;
      border: 1px solid #ffeeba;
      border-radius: 12px;
      color: #856404;
      text-align: center;
      margin-top: 20px;
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05);
    }

    .disabled-link {
      pointer-events: none;
      color: #999;
      cursor: default;
      text-decoration: none;
    }

    body {
      font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      min-height: 100vh;
      display: flex;
      align-items: center;
      justify-content: center;
      padding: 20px;
    }

    .container {
      max-width: 1140px;
      width: 100%;
      background: white;
      border-radius: 20px;
      box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
      overflow: hidden;
      animation: fadeIn 0.8s ease;
    }

    @keyframes fadeIn {
      from {
        opacity: 0;
        transform: translateY(30px);
      }

      to {
        opacity: 1;
        transform: translateY(0);
      }
    }

    /* Kompakt Header */
    .header {
      background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
      color: white;
      padding: 25px 40px;
      position: relative;
      overflow: hidden;
      display: flex;
      align-items: center;
      text-align: left;
    }

    .header::before {
      content: "";
      position: absolute;
      top: -50%;
      right: -50%;
      width: 200%;
      height: 200%;
      background: radial-gradient(circle,
          rgba(255, 255, 255, 0.1) 0%,
          transparent 70%);
      animation: pulse 15s infinite;
    }

    @keyframes pulse {

      0%,
      100% {
        transform: scale(1);
      }

      50% {
        transform: scale(1.1);
      }
    }

    .profile-icon {
      width: 50px;
      height: 50px;
      background: white;
      border-radius: 50%;
      margin: 0 20px 0 0;
      display: flex;
      align-items: center;
      justify-content: center;
      font-size: 24px;
      color: #667eea;
      box-shadow: 0 5px 20px rgba(0, 0, 0, 0.2);
      position: relative;
      z-index: 1;
      flex-shrink: 0;
    }

    .header-text {
      position: relative;
      z-index: 1;
    }

    .header h1 {
      font-size: 24px;
      margin-bottom: 4px;
    }

    .header p {
      font-size: 15px;
      opacity: 0.95;
      margin: 0;
    }

    .content {
      padding: 40px;
    }

    /* Breadcrumb */
    .breadcrumb {
      display: flex;
      list-style: none;
      padding: 0 0 25px 0;
      margin: 0 0 25px 0;
      border-bottom: 2px solid #f0f0f0;
      font-size: 15px;
    }

    .breadcrumb li {
      display: flex;
      align-items: center;
    }

    .breadcrumb li+li::before {
      content: "/";
      margin: 0 12px;
      color: #999;
    }

    .breadcrumb a {
      text-decoration: none;
      color: #667eea;
      font-weight: 600;
      transition: color 0.3s ease;
    }

    .breadcrumb a:hover {
      color: #764ba2;
    }

    .breadcrumb li.active {
      color: #555;
      font-weight: 500;
    }

    /* Ders Başlığı */
    .course-title {
      font-size: 28px;
      font-weight: 700;
      color: #667eea;
      margin-bottom: 25px;
      display: flex;
      align-items: center;
    }

    .course-title i {
      font-size: 26px;
      margin-right: 15px;
    }

    .course-layout {
      display: flex;
      gap: 30px;
    }

    /* Sidebar */
    .sidebar {
      width: 250px;
      flex-shrink: 0;
      background-color: #f8f9fa;
      border-radius: 12px;
      padding: 15px;
      border: 2px solid #e0e0e0;
    }

    .sidebar-nav {
      list-style: none;
    }

    .sidebar-nav a {
      display: block;
      text-decoration: none;
      color: #555;
      font-size: 16px;
      font-weight: 600;
      padding: 12px 15px;
      border-radius: 8px;
      margin-bottom: 8px;
      transition: all 0.3s ease;
      position: relative;
    }

    .sidebar-nav a i {
      width: 25px;
      margin-right: 10px;
      color: #888;
      transition: color 0.3s ease;
    }

    .sidebar-nav a:hover {
      background-color: #e9ecfb;
      color: #667eea;
    }

    .sidebar-nav a:hover i {
      color: #667eea;
    }

    .sidebar-nav a.active {
      background-color: #667eea;
      color: white;
      box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
    }

    .sidebar-nav a.active i {
      color: white;
    }

    /* Dropdown */
    .sidebar-dropdown-toggle {
      cursor: pointer;
    }

    .sidebar-dropdown-toggle::after {
      content: "\f107";
      font-family: "Font Awesome 6 Free";
      font-weight: 900;
      position: absolute;
      right: 15px;
      top: 14px;
      transition: transform 0.3s ease;
    }

    .sidebar-dropdown-toggle.open::after {
      transform: rotate(-180deg);
    }

    .sidebar-submenu {
      list-style: none;
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease-out;
      margin-left: 10px;
    }

    .sidebar-submenu a {
      font-size: 15px;
      font-weight: 500;
      color: #444;
      padding-left: 25px;
      margin-bottom: 5px;
    }

      .alert-info {

          background-color: #e7f0ff;

          border-left: 5px solid #667eea;

          padding: 15px;

          margin-bottom: 20px;

          border-radius: 4px;

          font-size: 15px;

          color: #2c3e50;

      }
    pre[class*="language-"] {
        border-radius: 12px;
        border: 1px solid #ddd;
        max-height: 500px; /* Kaydırma çubuğu için maksimum yükseklik */
        overflow: auto !important; /* Kaydırmayı zorunlu kıl */
        margin: 0;
        font-family: 'Consolas', 'Monaco', 'Andale Mono', 'Ubuntu Mono', monospace;
        font-size: 14px;
    }
    
    .sidebar-submenu a i {
      width: 20px;
      margin-right: 8px;
      font-size: 12px;
      color: #aaa;
    }

    .sidebar-submenu a:hover {
      background-color: #e0e6fa;
    }

    .sidebar-submenu a.active {
      background-color: #d1d8f5;
      color: #333;
      box-shadow: none;
    }

    /* Sağ İçerik Alanı */
    .main-content {
      flex-grow: 1;
      min-width: 0;
    }

    .main-content h2 {
      font-size: 24px;
      color: #333;
      margin-bottom: 20px;
    }

    .main-content p {
      font-size: 16px;
      line-height: 1.7;
      color: #555;
      margin-bottom: 15px;
    }

    /* Slayt Altı Uyarı */
    .slide-disclaimer {
      font-size: 13px !important;
      color: #666;
      text-align: center;
      padding: 0;
      margin-top: 15px;
      line-height: 1.5;
      background-color: transparent;
      border: none;
    }

    /* Footer */
    .footer {
      background: #f8f9fa;
      padding: 20px;
      text-align: center;
      color: #666;
      font-size: 14px;
      border-top: 2px solid #e0e0e0;
    }

    .social-links {
      margin-top: 15px;
    }

    .social-links a {
      display: inline-block;
      width: 40px;
      height: 40px;
      background: #667eea;
      color: white;
      border-radius: 50%;
      line-height: 40px;
      margin: 0 5px;
      text-decoration: none;
      transition: all 0.3s ease;
    }

    .social-links a:hover {
      background: #764ba2;
      transform: translateY(-3px);
    }

    /* Mobil */
    @media (max-width: 992px) {
      .course-layout {
        flex-direction: column;
      }

      .sidebar {
        width: 100%;
        margin-bottom: 20px;
      }
    }

    @media (max-width: 768px) {
      .course-grid {
        grid-template-columns: 1fr;
      }
    }

    @media (max-width: 600px) {
      .header {
        padding: 20px;
        flex-direction: column;
        align-items: flex-start;
      }

      .profile-icon {
        margin: 0 0 15px 0;
      }

      .header h1 {
        font-size: 22px;
      }

      .content {
        padding: 30px 20px;
      }

      .breadcrumb {
        font-size: 14px;
      }

    }