body.no-scroll {
  overflow: hidden !important;
}

.course-container {
  max-width: 900px;
  margin: 0 auto;
  padding: 1rem 1rem 5rem 1rem;
}

.main-content h2,
.main-content h3,
.main-content h4 {
  font-family: var(--font-headings);
  font-weight: 600;
  color: var(--text-headings);
}

.main-content h2 {
  font-size: 1.8rem;
  margin: 0 0 1rem 0;
}

.main-content h2 .concept-number {
  color: var(--primary-accent);
}

.sub-concept-title,
.main-content h4 {
  font-size: 1.3rem;
  margin: 2.5rem 0 1.5rem 0;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--border-color);
}

.main-content p,
.main-content ol,
.main-content ul {
  line-height: 1.75;
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 1.25rem;
}

.main-content ol,
.main-content ul {
  padding-left: 25px;
}

.main-content li {
  margin-bottom: 0.8rem;
  padding-left: 0.5rem;
}

.main-content li::marker {
  color: var(--primary-accent);
  font-weight: 600;
}

.concept-section,
.content-block {
  margin-top: 3rem;
  background-color: var(--bg-content);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-default);
}
.concept-section:hover,
.content-block:hover {
  box-shadow: var(--shadow-md);
}
.concept-section {
  padding: clamp(1.5rem, 5vw, 2.5rem);
}

.content-block .block-header {
  padding: 1.5rem;
  background: var(--bg-alt);
}
.content-block .block-header h2 {
  font-size: 1.5rem;
}

.content-block .block-content {
  padding: 1.5rem;
}

.grid-two-columns {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin-top: 2rem;
  padding: 1rem 0;
}

.grid-item {
  background: var(--bg-content);
  border-radius: 12px;
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: transform 0.2s ease;
}

.grid-item:hover {
  transform: translateY(-4px);
}
.grid-item strong {
  font-size: 1.1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.4rem;
  color: var(--text-headings);
}
.grid-item code {
  background: var(--primary-light);
  color: var(--primary-accent);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.9em;
}

@media (min-width: 768px) {
  .course-container {
    padding: 2rem 1.5rem 6rem 1.5rem;
  }
  .content-block .block-content {
    padding: 2.5rem;
  }
}

.btn-primary,
.btn-secondary,
.validation-btn,
.toggle-solution-btn,
.retry-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
  font-family: var(--font-headings);
  font-weight: 600;
  border-radius: var(--border-radius-md);
  cursor: pointer;
  transition: all 0.2s ease-in-out;
  border: 2px solid transparent;
  padding: 0.75rem 1.5rem;
  text-decoration: none;
}
.btn-primary:hover,
.btn-secondary:hover,
.validation-btn:hover,
.toggle-solution-btn:hover,
.retry-button:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
}
.btn-primary {
  color: var(--text-on-accent);
  background: var(--gradient-primary);
  box-shadow: var(--shadow-accent);
  margin: 1rem 0;
}
.btn-secondary,
.toggle-solution-btn {
  color: var(--primary-accent);
  background-color: var(--primary-light);
  border-color: var(--primary-light);
}
.btn-secondary:hover,
.toggle-solution-btn:hover {
  background-color: var(--primary-accent);
  color: var(--text-on-accent);
  border-color: var(--primary-accent);
}
.toggle-solution-btn {
  margin-top: 1.5rem;
}

.info-box,
.tip-box {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin: 2rem 0;
  padding: 1.5rem;
  border-radius: var(--border-radius-lg);
  border-width: 1px;
  border-style: solid;
}
.info-box-icon {
  margin-top: 3px;
}
.info-box-content h5 {
  font-family: var(--font-headings);
  font-size: 1.15rem;
  margin: 0 0 0.5rem 0;
  color: var(--text-headings);
}
.info-box-content p {
  font-size: 1rem;
  margin: 0;
}
.info-box {
  background-color: var(--info-bg);
  border-color: var(--info-border);
}
.info-box .lucide {
  stroke: var(--info-color);
}
.tip-box {
  background-color: var(--warning-bg);
  border-color: var(--warning-border);
}
.tip-box .lucide {
  stroke: var(--warning-color);
}

.image-placeholder-container {
  margin: 2.5rem 0;
}
.image-placeholder-container img {
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-lg);
}
.image-placeholder-container.zoomable img {
  cursor: zoom-in;
  transition: opacity 0.2s ease-in-out;
}
.image-placeholder-container.zoomable img:hover {
  opacity: 0.85;
}
.image-placeholder-container figcaption {
  text-align: center;
  font-style: italic;
  font-size: 0.95rem;
  color: var(--text-secondary);
  margin-top: 0.75rem;
  line-height: 1.5;
}

.code-card {
  background-color: #282c34;
  border-radius: var(--border-radius-lg);
  margin: 2rem 0;
  overflow: hidden;
}
.code-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1rem;
  background-color: #21252b;
  border-bottom: 1px solid #181a1f;
}
.code-card-header .code-title {
  font-size: 0.9rem;
  color: #abb2bf;
  font-family: var(--font-code);
}
.code-card-toolbar {
  display: flex;
  gap: 0.5rem;
}
.toolbar-button {
  display: grid;
  place-items: center;
  width: 32px;
  height: 32px;
  padding: 0;
  color: #abb2bf;
  background-color: transparent;
  border: none;
  border-radius: var(--border-radius-sm);
  cursor: pointer;
}
.toolbar-button .lucide {
  width: 18px;
  height: 18px;
}
.toolbar-button span {
  display: none;
}
.toolbar-button:hover {
  background-color: #3e4451;
  color: #fff;
  transform: none;
  box-shadow: none;
}
.toolbar-button.btn-copy:hover {
  color: var(--primary-accent);
  background-color: var(--primary-light);
}
.code-card-content pre {
  margin: 0 !important;
  padding: 1.5rem !important;
  background: transparent !important;
}
.code-card-content code[class*="language-"] {
  padding: 0 !important;
}

.modal-overlay,
.image-modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1000;
  background-color: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(5px);
  padding: 1rem;
  justify-content: center;
  align-items: center;
}
.modal-content {
  position: relative;
  background-color: var(--bg-content);
  color: var(--text-primary);
  padding: 2rem;
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-xl);
  max-width: 600px;
  width: 100%;
  max-height: 90vh;
  overflow-y: auto;
  animation: modal-fade-in 0.3s ease-out;
}
.modal-close {
  position: absolute;
  top: 10px;
  right: 15px;
  font-size: 2rem;
  font-weight: bold;
  color: var(--text-color-secondary);
  cursor: pointer;
  line-height: 1;
  transition: color 0.2s ease;
}
.modal-close:hover {
  color: var(--danger-color);
}
.modal-content h2 {
  font-family: var(--font-headings);
  font-size: 1.6rem;
  margin-top: 0;
  margin-bottom: 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  color: var(--text-headings);
}

.modal-steps {
  list-style-type: none;
  padding-left: 0;
  counter-reset: step-counter;
  margin-bottom: 2rem;
}
.modal-steps li {
  counter-increment: step-counter;
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.25rem;
  font-size: 1.05rem;
}
.modal-steps li::before {
  content: counter(step-counter);
  font-weight: 700;
  font-size: 1rem;
  background: var(--primary-accent);
  color: var(--text-on-accent);
  border-radius: 50%;
  width: 28px;
  height: 28px;
  min-width: 28px;
  display: inline-flex;
  justify-content: center;
  align-items: center;
  margin-top: -2px;
}
.modal-image {
  margin-top: 1.5rem;
  text-align: center;
}
.modal-image img {
  max-width: 100%;
  border-radius: var(--border-radius-md);
  border: 1px solid var(--border-color);
}
.modal-image figcaption {
  font-size: 0.9rem;
  color: var(--text-color-secondary);
  margin-top: 0.5rem;
  font-style: italic;
}

.image-modal-overlay {
  z-index: 2000;
  background-color: rgba(0, 0, 0, 0.85);
  backdrop-filter: blur(8px);
  flex-direction: column;
  padding: 20px;
}
.image-modal-content {
  margin: auto;
  display: block;
  max-width: 90%;
  max-height: 80%;
  border-radius: var(--border-radius-md);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4);
  animation: zoomIn 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
}
.image-modal-caption {
  margin-top: 15px;
  color: #ccc;
  text-align: center;
  font-size: 1.1rem;
  font-weight: 500;
  letter-spacing: 0.5px;
  text-shadow: 1px 1px 5px rgba(0, 0, 0, 0.8);
  animation: fadeIn 0.5s 0.2s ease-in-out forwards;
  opacity: 0;
}
#closeImageModal {
  z-index: 2010;
  color: rgba(255, 255, 255, 0.8);
  font-size: 2.5rem;
}
#closeImageModal:hover {
  color: #fff;
}

.modal-content.large {
  max-width: 800px;
}
.progress-details-container {
  margin-top: 1.5rem;
  max-height: 60vh;
  overflow-y: auto;
  padding-right: 10px;
}
.progress-module-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 15px;
  border-radius: 8px;
  background-color: var(--background-secondary);
  margin-bottom: 10px;
  border: 1px solid var(--border-color);
  gap: 1rem;
}
.progress-module-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.05);
}
.progress-module-info {
  display: flex;
  align-items: center;
  gap: 15px;
  flex-grow: 1;
  flex-shrink: 1;
  min-width: 0;
}
.progress-module-info .lucide {
  color: var(--text-color-secondary);
}
.progress-module-name {
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.progress-module-status {
  display: flex;
  align-items: center;
  gap: 15px;
  flex-shrink: 0;
}
.progress-badge {
  padding: 4px 10px;
  border-radius: 12px;
  font-size: 0.8rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 5px;
}
.progress-badge.validated {
  background-color: var(--success-bg);
  color: var(--success-color);
}
.progress-badge.not-validated {
  background-color: var(--warning-bg);
  color: var(--warning-color);
}
.progress-badge.no-quiz {
  background-color: var(--background-tertiary);
  color: var(--text-color-secondary);
}
.progress-badge.info {
  background-color: var(--background-tertiary, #e9ecef);
  color: var(--text-color-secondary, #6c757d);
}

@media (max-width: 640px) {
  .modal-content {
    padding: 1.5rem;
  }
  .modal-content h2 {
    font-size: 1.4rem;
  }
}

.course-hero-card {
  background-color: var(--bg-content);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-lg);
  padding: 2rem;
  margin-bottom: 3rem;
  box-shadow: var(--shadow-md);
  text-align: center;
  border-top: 4px solid var(--primary-accent);
}
@media (min-width: 768px) {
  .course-hero-card {
    padding: 2.5rem 3rem;
  }
}
.hero-title-group .header-icon-wrapper {
  margin: 0 auto 1.5rem auto;
}
.hero-title-group .header-icon-wrapper svg {
  width: 40px;
  height: 40px;
  stroke-width: 2.2;
}
.hero-title-group h1 {
  font-size: clamp(2rem, 5vw, 2.8rem);
}
.hero-title-group .subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.2rem);
  max-width: 60ch;
  margin: 1rem auto 0 auto;
  color: var(--text-secondary);
}

.dropdown-menu {
  display: none;
  flex-direction: column;
  gap: 5px;
  padding: 5px;
}
.user-dropdown.active .dropdown-menu {
  display: flex;
}
.dropdown-item {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
  padding: 10px 15px;
  font-family: "Poppins", sans-serif;
  font-size: 0.95rem;
  font-weight: 500;
  text-align: left;
  background-color: transparent;
  color: var(--text-color);
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: background-color 0.2s ease-in-out, color 0.2s ease-in-out;
}
.dropdown-item i {
  width: 18px;
  text-align: center;
  color: inherit;
  transition: color 0.2s ease-in-out;
}
.dropdown-item:hover {
  background-color: var(--background-secondary);
}
#progressBtn {
  color: var(--primary-color, #0d6efd);
}
#progressBtn:hover {
  background-color: rgba(13, 110, 253, 0.1);
}
#logoutBtn {
  color: var(--danger-color, #dc3545);
}
#logoutBtn:hover {
  background-color: rgba(220, 53, 69, 0.1);
  color: var(--danger-color-dark, #b02a37);
}

.validation-buttons {
  display: flex;
  margin-top: 1.5rem;
}
.validation-btn {
  flex: 1;
  font-size: 1rem;
}
.validation-btn.disabled {
  opacity: 0.5;
  cursor: not-allowed;
}
.validation-feedback {
  margin-top: 1.5rem;
  padding: 1rem 1.25rem;
  border-radius: var(--border-radius-md);
  font-size: 1rem;
  font-weight: 500;
  line-height: 1.6;
  border: 1px solid transparent;
}
.validation-feedback.positive {
  background-color: var(--success-bg, #e6f9ee);
  color: var(--success-color, #2e7d32);
  border-color: var(--success-color, #2e7d32);
}
.validation-feedback.negative,
.validation-feedback.info {
  background-color: var(--danger-bg, #fdebec);
  color: var(--danger-color, #c62828);
  border-color: var(--danger-color, #c62828);
}

.exercise-note {
  background: var(--bg-alt);
  border: none;
  border-left: 4px solid var(--primary-accent);
  border-radius: var(--border-radius-md);
  padding: 1.5rem;
  margin-bottom: 2rem;
}
.exercise-note strong {
  color: var(--primary-accent);
}
.toggle-solution-btn {
  margin-top: 1.5rem;
}
.solution-content {
  margin-top: 1.5rem;
  border-top: 1px solid var(--border-color);
  padding-top: 1.5rem;
  display: none;
}
.solution-content.visible {
  display: block;
}

.section-box.quiz {
  padding: 2rem;
}
.section-box.quiz h4 {
  font-family: var(--font-headings);
  font-size: 1.4rem;
  color: var(--primary-accent);
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
.quiz-question {
  padding: 1.5rem;
  margin-bottom: 2rem;
  background-color: var(--bg-alt);
  border: 1px solid var(--border-color);
  border-radius: var(--border-radius-md);
  transition: box-shadow var(--transition-default);
}
.quiz-question:hover {
  box-shadow: var(--shadow-sm);
}
.quiz-question p {
  font-weight: 600;
  font-size: 1.1rem;
  color: var(--text-headings);
  margin-bottom: 1rem;
}
.quiz-options {
  list-style-type: none;
  padding-left: 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.quiz-options li {
  position: relative;
  padding: 1rem 1.25rem;
  border: 2px solid var(--border-color);
  border-radius: var(--border-radius-md);
  font-weight: 500;
  background-color: var(--bg-content);
  color: var(--text-primary);
  cursor: pointer;
  transition: all 0.2s ease;

  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
}
.quiz-options li:hover:not(.correct):not(.wrong):not(.pre-selected) {
  background-color: var(--primary-light);
  border-color: var(--primary-accent);
}
.quiz-options li.pre-selected {
  border-color: var(--primary-accent);
  background-color: var(--primary-light);
}
.quiz-options li.pre-selected::after {
  content: "✔";
  font-weight: bold;
  font-size: 1.2rem;
  position: absolute;
  top: 50%;
  right: 1.25rem;
  transform: translateY(-50%);
  color: var(--primary-accent);
  background-color: white;
  border-radius: 50%;
  width: 28px;
  height: 28px;
  display: flex;
  align-items: center;
  justify-content: center;
  animation: pulse 1.2s infinite;
}
.quiz-options li.correct {
  font-weight: 600;
  background-color: var(--success-bg);
  border-color: var(--success-color);
  color: var(--success-color);
}

.quiz-options li.incorrect {
  font-weight: 600;
  background-color: var(--danger-bg);
  border-color: var(--danger-color);
  color: var(--danger-color);
}
.quiz-feedback {
  display: none;
  padding: 1rem;
  margin-top: 1rem;
  font-size: 0.95rem;
  text-align: center;
  border-radius: var(--border-radius-md);
  opacity: 0;
  transition: opacity var(--transition-default);
}
.quiz-feedback.visible {
  display: block;
  opacity: 1;
}
.quiz-feedback.correct {
  color: var(--success-color);
  background-color: var(--success-bg, #e6f9ee);
  border: 1px solid var(--success-color);
}
.quiz-feedback.incorrect {
  color: var(--danger-color);
  background-color: var(--danger-bg, #fdebec);
  border: 1px solid var(--danger-color);
}
.quiz-score-box {
  padding: 1.5rem;
  margin-top: 2.5rem;
  font-size: 1rem;
  background-color: var(--primary-light);
  border-left: 4px solid var(--primary-accent);
  border-radius: var(--border-radius-md);
  text-align: center;
}
.quiz-score-box h5 {
  margin-bottom: 0.75rem;
  font-family: var(--font-headings);
  font-size: 1.1rem;
  color: var(--primary-accent);
}
.retry-button {
  color: var(--primary-accent);
  background-color: var(--primary-light);
  border-color: var(--primary-light);
  margin: 1.5rem auto 0 auto;
}
.retry-button:hover {
  background-color: var(--primary-accent);
  color: var(--text-on-accent);
  border-color: var(--primary-accent);
}

.quiz-cert-tabs {
  display: flex;
  justify-content: center;
  gap: 1rem;
  margin-bottom: 2rem;
}
.tab-btn {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 0.6rem 1.2rem;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
}
.tab-btn.active {
  background-color: var(--accent);
  color: var(--accent-text);
  border-color: var(--accent);
}
.tab-btn.locked {
  opacity: 0.5;
  cursor: not-allowed;
}
.certificate-display-area {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2rem;
  padding: 2rem 1rem;
  background: var(--background-color, #fdfdfd);
}
.certificate {
  width: 100%;
  max-width: 960px;
  padding: 2.5rem;
  border: 3px solid #d4af37;
  border-radius: 8px;
  background-color: #fff;
  text-align: center;
  box-shadow: 0 4px 10px rgba(0, 0, 0, 0.05);
  position: relative;
}
.certificate::before {
  content: "";
  position: absolute;
  top: 12px;
  left: 12px;
  right: 12px;
  bottom: 12px;
  border: 1px solid #e8d5a3;
  border-radius: 4px;
  pointer-events: none;
}
.certificate h1 {
  font-family: Georgia, serif;
  font-size: 1.8rem;
  font-weight: bold;
  color: #b4931c;
  margin-bottom: 0.5rem;
}
.certificate .sub {
  font-style: italic;
  font-size: 0.95rem;
  color: #555;
  margin-bottom: 1rem;
}
.certificate .recipient {
  text-transform: uppercase;
  font-weight: bold;
  font-size: 0.9rem;
  letter-spacing: 1px;
  margin-top: 1rem;
}
.certificate h2 {
  font-family: Georgia, serif;
  font-style: italic;
  font-size: 1.6rem;
  color: #000;
  margin: 0.4rem 0 1.2rem;
}
.certificate .description {
  font-size: 0.95rem;
  color: #333;
}
.certificate .course-title {
  color: #3a52c4;
  font-weight: bold;
  font-size: 1rem;
  margin: 0.5rem 0 1.5rem;
}
.certificate .date-line {
  font-size: 0.9rem;
  color: #444;
}
.certificate .signature-section {
  margin-top: 2rem;
}
.signature-line {
  width: 120px;
  height: 1px;
  background: #bbb;
  margin: 0 auto 0.4rem;
}
.certificate .signature p {
  margin: 0;
  font-weight: bold;
  color: #333;
}
#downloadCertBtn {
  margin-top: 1.5rem;
  align-self: center;
}
@media (max-width: 600px) {
  .certificate {
    padding: 1.5rem;
    font-size: 0.9rem;
  }
  .certificate h1 {
    font-size: 1.4rem;
  }
  .certificate h2 {
    font-size: 1.3rem;
  }
  .certificate .course-title {
    font-size: 0.95rem;
  }
  #downloadCertBtn {
    width: 100%;
  }
}

.loading-spinner,
.spin {
  animation: spin 1s linear infinite;
}

@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}
@keyframes modal-fade-in {
  from {
    opacity: 0;
    transform: scale(0.95) translateY(10px);
  }
  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}
@keyframes zoomIn {
  from {
    transform: scale(0.8);
    opacity: 0;
  }
  to {
    transform: scale(1);
    opacity: 1;
  }
}
@keyframes fadeIn {
  to {
    opacity: 1;
  }
}
@keyframes pulse {
  0% {
    transform: translateY(-50%) scale(1);
    box-shadow: 0 0 0 0 rgba(13, 110, 253, 0.4);
  }
  70% {
    transform: translateY(-50%) scale(1);
    box-shadow: 0 0 0 10px rgba(13, 110, 253, 0);
  }
  100% {
    transform: translateY(-50%) scale(1);
    box-shadow: 0 0 0 0 rgba(13, 110, 253, 0);
  }
}