@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
  --font-family: 'Space Grotesk', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  --bg-page: #f8fafc;
  --bg-surface: #ffffff;
  --bg-subtle: #f1f5f9;
  --bg-muted: #e2e8f0;

  --blue-50: #eff6ff;
  --blue-100: #dbeafe;
  --blue-200: #bfdbfe;
  --blue-500: #3b82f6;
  --blue-600: #2563eb;
  --blue-700: #1d4ed8;
  --blue-800: #1e40af;

  --text-main: #0f172a;
  --text-body: #334155;
  --text-muted: #64748b;
  --text-light: #94a3b8;

  --border-lighter: #f1f5f9;
  --border-subtle: #edf2f7;
  --border-medium: #cbd5e1;

  --success-bg: #ecfdf5;
  --success-text: #059669;
  --success-border: #a7f3d0;
  --error-bg: #fef2f2;
  --error-text: #dc2626;
  --error-border: #fecaca;

  --radius-xs: 8px;
  --radius-sm: 14px;
  --radius-md: 20px;
  --radius-lg: 28px;
  --radius-xl: 36px;
  --radius-pill: 9999px;

  --shadow-sm: 0 1px 3px rgba(15, 23, 42, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(15, 23, 42, 0.06), 0 2px 4px -2px rgba(15, 23, 42, 0.05);
  --shadow-modal: 0 16px 24px -4px rgba(15, 23, 42, 0.1);

  --transition-fast: 0.15s ease;
  --transition-smooth: 0.2s ease;
}

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: var(--font-family) !important;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family) !important;
  background-color: var(--bg-page);
  color: var(--text-body);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  opacity: 1;
  transition: opacity 0.15s ease;
}

body.page-leaving {
  opacity: 0;
}

main {
  animation: pureFade 0.22s ease-out forwards;
}

@keyframes pureFade {
  from { opacity: 0; }
  to { opacity: 1; }
}

.fade-in-content {
  animation: pureFade 0.25s ease-out forwards;
}

h1, h2, h3, h4, h5, h6 {
  color: var(--text-main);
  font-weight: 700;
  letter-spacing: -0.025em;
  line-height: 1.25;
}

a {
  color: inherit;
  text-decoration: none;
  transition: color var(--transition-fast);
}

.section-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

.text-center-block {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 36px auto;
}

.section-title {
  font-size: 2.15rem;
  margin-top: 10px;
  margin-bottom: 10px;
}

.section-subtitle {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.55;
}

.highlight-blue {
  color: var(--blue-600);
}

.category-tag {
  display: inline-flex;
  align-items: center;
  padding: 5px 13px;
  background-color: var(--blue-50);
  border: 1px solid var(--blue-200);
  color: var(--blue-700);
  border-radius: var(--radius-pill);
  font-size: 0.78rem;
  font-weight: 600;
  width: fit-content;
}

.tag-chip {
  font-size: 0.74rem;
  padding: 4px 10px;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  color: var(--text-body);
  font-weight: 500;
}

.horizontal-divider {
  border: none;
  height: 1px;
  background-color: var(--border-lighter);
  width: 100%;
  margin: 0;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.92rem;
  padding: 9px 20px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  cursor: pointer;
  box-shadow: none;
  outline: none;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
  white-space: nowrap;
}

.btn-primary {
  background-color: var(--blue-600);
  color: #ffffff;
  border-color: var(--blue-600);
}

.btn-primary:hover {
  background-color: var(--blue-700);
  border-color: var(--blue-700);
}

.btn-outline {
  background-color: var(--bg-surface);
  color: var(--text-main);
  border-color: var(--border-medium);
}

.btn-outline:hover {
  background-color: var(--bg-subtle);
  border-color: var(--blue-600);
  color: var(--blue-700);
}

.btn-secondary {
  background-color: var(--blue-50);
  color: var(--blue-700);
  border-color: var(--blue-200);
}

.btn-secondary:hover {
  background-color: var(--blue-100);
  color: var(--blue-800);
}

.btn-lg {
  padding: 12px 26px;
  font-size: 1rem;
}

.btn-sm {
  padding: 6px 14px;
  font-size: 0.82rem;
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border-lighter);
  padding: 14px 0;
}

.nav-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand-logo {
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-main);
  display: inline-flex;
  align-items: center;
}

.brand-logo:hover {
  color: var(--blue-600);
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: 0.92rem;
  font-weight: 500;
  color: var(--text-muted);
  position: relative;
  padding: 4px 0;
  transition: color var(--transition-fast);
}

.nav-link:hover {
  color: var(--blue-600);
}

.nav-link.active {
  color: var(--blue-600);
  font-weight: 600;
}

.nav-link.active::after {
  content: "";
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 100%;
  height: 2px;
  background-color: var(--blue-600);
  border-radius: var(--radius-pill);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.search-box {
  position: relative;
  display: flex;
  align-items: center;
  width: 250px;
  flex-shrink: 0;
}

.search-box input {
  padding: 8px 16px 8px 36px;
  font-size: 0.88rem;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-pill);
  outline: none;
  width: 100%;
  color: var(--text-main);
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.search-box input:focus {
  background-color: var(--bg-surface);
  border-color: var(--blue-600);
  
}

.search-icon {
  position: absolute;
  left: 12px;
  color: var(--text-muted);
  pointer-events: none;
}

.hero-section {
  padding: 56px 0 50px 0;
  background-color: var(--bg-surface);
  border-bottom: 1px solid var(--border-lighter);
}

.hero-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  align-items: center;
  gap: 48px;
}

.hero-title {
  font-size: 2.85rem;
  line-height: 1.2;
  margin-bottom: 14px;
  color: var(--text-main);
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-muted);
  margin-bottom: 26px;
  max-width: 560px;
  line-height: 1.55;
}

.hero-cta-group {
  display: flex;
  gap: 14px;
  margin-bottom: 34px;
  flex-wrap: wrap;
}

.metrics-card {
  display: flex;
  align-items: center;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 14px 22px;
  max-width: 540px;
}

.metric-item {
  display: flex;
  flex-direction: column;
}

.metric-val {
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--blue-700);
}

.metric-label {
  font-size: 0.78rem;
  color: var(--text-muted);
  font-weight: 500;
}

.metric-divider {
  width: 1px;
  height: 36px;
  background-color: var(--border-subtle);
  margin: 0 22px;
}

.hero-visual-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 26px;
  box-shadow: var(--shadow-md);
}

.preview-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-lighter);
}

.preview-body h3 {
  font-size: 1.32rem;
  margin-bottom: 8px;
}

.preview-desc {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin-bottom: 18px;
  line-height: 1.5;
}

.progress-wrap {
  background-color: var(--bg-subtle);
  padding: 12px 14px;
  border-radius: var(--radius-sm);
  margin-bottom: 18px;
}

.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  margin-bottom: 8px;
}

.progress-label strong {
  color: var(--blue-600);
}

.progress-bar-bg {
  height: 8px;
  background-color: var(--border-subtle);
  border-radius: var(--radius-pill);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background-color: var(--blue-600);
  border-radius: var(--radius-pill);
  transition: width 0.3s ease;
}

.preview-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--border-lighter);
}

.courses-section {
  padding: 52px 0 68px 0;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  margin-bottom: 28px;
  flex-wrap: wrap;
  gap: 18px;
}

.category-filters {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

.filter-pill {
  font-size: 0.85rem;
  font-weight: 600;
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  color: var(--text-muted);
  padding: 7px 16px;
  border-radius: var(--radius-pill);
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.filter-pill:hover {
  background-color: var(--bg-subtle);
  border-color: var(--blue-500);
  color: var(--blue-600);
}

.filter-pill.active {
  background-color: var(--blue-600);
  color: #ffffff;
  border-color: var(--blue-600);
}

.course-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
  gap: 24px;
}

.course-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 24px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  box-shadow: var(--shadow-sm);
  transition: border-color var(--transition-fast), background-color var(--transition-fast);
}

.course-card:hover {
  border-color: var(--blue-200);
  background-color: #fbfcfe;
}

.course-card-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.course-card-title {
  font-size: 1.22rem;
  margin-bottom: 8px;
  line-height: 1.35;
}

.course-card-summary {
  font-size: 0.88rem;
  color: var(--text-muted);
  margin-bottom: 18px;
  line-height: 1.5;
}

.course-tags-row {
  display: flex;
  gap: 6px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.course-card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 14px;
  border-top: 1px solid var(--border-lighter);
}

.course-meta-detail {
  font-size: 0.82rem;
  color: var(--text-muted);
  font-weight: 500;
}

.pagination-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  margin-top: 40px;
}

.pagination-info {
  font-size: 0.86rem;
  color: var(--text-muted);
  font-weight: 500;
}

.pagination-controls {
  display: flex;
  align-items: center;
  gap: 8px;
}

.page-number-btn {
  width: 36px;
  height: 36px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-pill);
  border: 1px solid var(--border-medium);
  background-color: var(--bg-surface);
  color: var(--text-main);
  font-size: 0.88rem;
  font-weight: 600;
  cursor: pointer;
  outline: none;
  transition: background-color var(--transition-fast), border-color var(--transition-fast), color var(--transition-fast);
}

.page-number-btn:hover:not(.active) {
  background-color: var(--bg-subtle);
  border-color: var(--blue-600);
  color: var(--blue-700);
}

.page-number-btn.active {
  background-color: var(--blue-600);
  border-color: var(--blue-600);
  color: #ffffff;
}

.pathway-list {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.pathway-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 28px;
  box-shadow: var(--shadow-sm);
  transition: border-color var(--transition-fast);
}

.pathway-card:hover {
  border-color: var(--blue-200);
}

.pathway-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}

.pathway-steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
  margin-top: 20px;
}

.step-node {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 18px;
}

.step-node h4 {
  font-size: 1rem;
  margin-bottom: 6px;
}

.step-node p {
  font-size: 0.84rem;
  color: var(--text-muted);
  line-height: 1.45;
}

.lab-container-grid {
  display: grid;
  grid-template-columns: 1fr 1.3fr;
  gap: 36px;
  align-items: start;
}

.lab-panel {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px;
  box-shadow: var(--shadow-md);
}

.quiz-option-btn {
  display: flex;
  align-items: baseline;
  gap: 12px;
  width: 100%;
  padding: 14px 18px;
  background-color: var(--bg-surface);
  border: 1.5px solid var(--border-subtle);
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  text-align: left;
  cursor: pointer;
  color: var(--text-body);
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
  margin-bottom: 10px;
}

.quiz-option-btn:hover:not(:disabled) {
  background-color: var(--bg-subtle);
  border-color: var(--blue-500);
}

.quiz-option-btn.selected {
  background-color: var(--blue-50);
  border-color: var(--blue-600);
  color: var(--blue-800);
}

.quiz-option-btn.correct {
  background-color: var(--success-bg);
  border-color: var(--success-border);
  color: var(--success-text);
  font-weight: 600;
}

.quiz-option-btn.incorrect {
  background-color: var(--error-bg);
  border-color: var(--error-border);
  color: var(--error-text);
}

.quiz-key {
  font-weight: 700;
  color: var(--text-muted);
  flex-shrink: 0;
}

.about-columns {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  gap: 36px;
}

.about-card {
  background-color: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 32px;
}

.meta-kv-table {
  width: 100%;
  border-collapse: collapse;
}

.meta-kv-table td {
  padding: 10px 0;
  border-bottom: 1px solid var(--border-subtle);
  font-size: 0.88rem;
}

.meta-kv-table td:first-child {
  color: var(--text-muted);
  font-weight: 500;
}

.meta-kv-table td:last-child {
  color: var(--text-main);
  font-weight: 600;
  text-align: right;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  background-color: rgba(15, 23, 42, 0.45);
  backdrop-filter: blur(4px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  padding: 20px;
  animation: pureFade 0.2s ease-out;
}

.modal-box {
  background-color: var(--bg-surface);
  border-radius: var(--radius-xl);
  max-width: 640px;
  width: 100%;
  padding: 34px;
  box-shadow: var(--shadow-modal);
  border: 1px solid var(--border-subtle);
  position: relative;
  max-height: 88vh;
  overflow-y: auto;
  animation: pureFade 0.2s ease-out;
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.modal-close-btn {
  background: transparent;
  border: none;
  font-size: 1.6rem;
  cursor: pointer;
  color: var(--text-muted);
  line-height: 1;
  padding: 4px;
  border-radius: 50%;
  transition: color var(--transition-fast);
}

.modal-close-btn:hover {
  color: var(--text-main);
}

.modal-title {
  font-size: 1.65rem;
  margin-bottom: 10px;
}

.modal-summary {
  font-size: 0.95rem;
  color: var(--text-muted);
  margin-bottom: 22px;
  line-height: 1.55;
}

.modal-meta-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 22px;
  background-color: var(--bg-subtle);
  padding: 14px;
  border-radius: var(--radius-md);
}

.meta-col {
  display: flex;
  flex-direction: column;
}

.meta-k {
  font-size: 0.7rem;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 2px;
}

.meta-col strong {
  font-size: 0.85rem;
  color: var(--text-main);
}

.syllabus-module-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 24px;
}

.syllabus-item {
  display: grid;
  grid-template-columns: 85px 1fr;
  gap: 12px;
  padding: 12px 16px;
  background-color: var(--bg-page);
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
}

.syllabus-week {
  font-weight: 700;
  font-size: 0.82rem;
  color: var(--blue-700);
}

.syllabus-content strong {
  display: block;
  font-size: 0.88rem;
  color: var(--text-main);
}

.syllabus-content span {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.modal-footer {
  display: flex;
  justify-content: flex-end;
  gap: 10px;
  padding-top: 14px;
  border-top: 1px solid var(--border-subtle);
}

.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  z-index: 2000;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toast {
  background-color: var(--bg-surface);
  color: var(--text-main);
  border: 1px solid var(--blue-200);
  padding: 11px 18px;
  border-radius: var(--radius-pill);
  font-size: 0.88rem;
  font-weight: 600;
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.08);
  display: flex;
  align-items: center;
  gap: 10px;
  animation: pureFade 0.2s ease-out;
}

.toast svg {
  color: var(--blue-600);
  flex-shrink: 0;
}

.site-footer {
  background-color: var(--bg-surface);
  border-top: 1px solid var(--border-lighter);
  padding: 56px 0 32px 0;
}

.footer-content {
  display: grid;
  grid-template-columns: 1.2fr 2fr;
  gap: 56px;
  margin-bottom: 36px;
}

.footer-brand .brand-logo {
  font-size: 1.35rem;
  margin-bottom: 12px;
  display: block;
}

.footer-tagline {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.5;
  margin-bottom: 20px;
  max-width: 320px;
}

.footer-links-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px;
}

.footer-col h5 {
  font-size: 0.88rem;
  margin-bottom: 14px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-main);
}

.footer-col a {
  display: block;
  font-size: 0.86rem;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.footer-col a:hover {
  color: var(--blue-600);
}

.copyright-bar {
  padding-top: 24px;
  border-top: 1px solid var(--border-lighter);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.8rem;
  color: var(--text-light);
  flex-wrap: wrap;
  gap: 12px;
}

@media (max-width: 992px) {
  .hero-container, .lab-container-grid, .about-columns {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .pathway-steps {
    grid-template-columns: 1fr;
  }
  .footer-content {
    grid-template-columns: 1fr;
    gap: 36px;
  }
}

@media (max-width: 768px) {
  .site-header .main-nav {
    display: none;
  }
  .search-box {
    width: 170px;
  }
  .hero-title {
    font-size: 2.2rem;
  }
}