:root {
  --bg: #0f172a;
  --bg-soft: #111827;
  --panel: #111827;
  --panel-2: #1f2937;
  --panel-3: #0b1220;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --accent-2: #22c55e;
  --accent-3: #a78bfa;
  --danger: #ef4444;
  --gold: #fbbf24;
  --border: rgba(255, 255, 255, 0.08);
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
}

body.light {
  --bg: #f8fafc;
  --bg-soft: #eef2ff;
  --panel: #ffffff;
  --panel-2: #f8fafc;
  --panel-3: #edf2f7;
  --text: #0f172a;
  --muted: #475569;
  --accent: #0284c7;
  --accent-2: #16a34a;
  --accent-3: #7c3aed;
  --danger: #dc2626;
  --gold: #ca8a04;
  --border: rgba(15, 23, 42, 0.08);
  --shadow: 0 10px 25px rgba(15, 23, 42, 0.08);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  font-family: "Inter", Arial, Helvetica, sans-serif;
  background:
    radial-gradient(circle at top left, rgba(56, 189, 248, 0.12), transparent 25%),
    radial-gradient(circle at top right, rgba(34, 197, 94, 0.10), transparent 25%),
    var(--bg);
  color: var(--text);
}

body {
  min-height: 100vh;
}

.app-shell {
  width: min(1450px, 96%);
  margin: 0 auto;
  padding: 20px 0 32px;
}

.topbar,
.hero-card,
.panel,
.stat-card,
.lesson-item,
.filter-btn,
.search-input,
.primary-btn,
.ghost-btn,
.danger-btn,
.code-block,
.tab-btn,
.roadmap-card,
.challenge-item,
.challenge-card,
.certificate-form-card,
.certificate-preview,
.mini-box,
.mini-metric,
.project-card,
.exam-question-card,
.exam-result-box,
.diagram-box,
.quiz-score-box {
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

.topbar {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  align-items: center;
  padding: 18px 20px;
  border-radius: 18px;
  background: rgba(17, 24, 39, 0.7);
  backdrop-filter: blur(12px);
}

body.light .topbar {
  background: rgba(255, 255, 255, 0.8);
}

.brand {
  display: flex;
  align-items: center;
  gap: 14px;
}

.brand-logo-image {
  width: 56px;
  height: 56px;
  object-fit: contain;
}

.brand h1 {
  margin: 0 0 4px;
  font-family: "Space Grotesk", "Inter", sans-serif;
  font-size: 1.4rem;
}

.brand p {
  margin: 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.topbar-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.network-link {
  color: var(--text);
  text-decoration: none;
  font-size: 0.88rem;
  font-weight: 700;
}

.network-link:hover {
  color: var(--accent);
}

.hero {
  margin: 22px 0;
}

.hero-card {
  padding: 28px;
  border-radius: 24px;
  background:
    linear-gradient(135deg, rgba(56, 189, 248, 0.12), rgba(34, 197, 94, 0.08)),
    var(--panel);
}

.hero-card h2 {
  margin: 12px 0 10px;
  font-family: "Space Grotesk", "Inter", sans-serif;
  font-size: 2rem;
}

.hero-card p {
  margin: 0;
  color: var(--muted);
  max-width: 820px;
}

.track-note {
  margin-top: 18px;
  color: var(--muted);
  line-height: 1.7;
}

.track-note a {
  color: var(--accent);
  text-decoration: none;
}

.hero-stats {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 14px;
  margin-top: 22px;
}

.stat-card {
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.03);
  padding: 18px;
}

body.light .stat-card {
  background: rgba(15, 23, 42, 0.03);
}

.stat-label {
  display: block;
  color: var(--muted);
  font-size: 0.9rem;
  margin-bottom: 8px;
}

.stat-card strong {
  font-size: 1.15rem;
}

.panel {
  background: var(--panel);
  border-radius: 22px;
  padding: 20px;
}

.tabs-panel {
  margin-bottom: 20px;
}

.tabs-row {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.tab-btn,
.filter-btn,
.primary-btn,
.ghost-btn,
.danger-btn {
  border-radius: 12px;
  padding: 10px 14px;
  cursor: pointer;
  color: var(--text);
  transition: 0.2s ease;
  background: var(--panel-2);
}

.tab-btn:hover,
.filter-btn:hover,
.primary-btn:hover,
.ghost-btn:hover,
.danger-btn:hover {
  transform: translateY(-1px);
}

.tab-btn.active,
.filter-btn.active {
  background: var(--accent);
  color: white;
}

.primary-btn {
  background: var(--accent);
  color: white;
}

.ghost-btn {
  background: transparent;
}

.danger-btn {
  background: rgba(239, 68, 68, 0.16);
  color: #fff;
}

body.light .danger-btn {
  color: var(--danger);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
}

.main-grid {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 20px;
}

.sidebar {
  position: sticky;
  top: 14px;
  max-height: calc(100vh - 28px);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.sidebar-top {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.search-input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 14px;
  background: var(--panel-2);
  color: var(--text);
  outline: none;
}

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

.lesson-list {
  margin-top: 16px;
  overflow-y: auto;
  padding-right: 4px;
}

.lesson-item {
  border-radius: 16px;
  background: var(--panel-2);
  padding: 14px;
  margin-bottom: 12px;
  cursor: pointer;
  transition: 0.2s ease;
}

.lesson-item:hover {
  transform: translateY(-2px);
}

.lesson-item.active {
  outline: 2px solid var(--accent);
}

.lesson-item h4 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.lesson-meta {
  display: flex;
  justify-content: space-between;
  gap: 10px;
  font-size: 0.85rem;
  color: var(--muted);
}

.lesson-complete {
  color: var(--accent-2);
  font-weight: 700;
}

.content-column {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.lesson-header,
.section-header {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: flex-start;
  flex-wrap: wrap;
}

.lesson-header h2,
.section-header h2 {
  margin: 10px 0 8px;
  font-size: 1.8rem;
}

.lesson-actions,
.challenge-actions,
.certificate-actions,
.exam-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.muted {
  color: var(--muted);
}

.pill {
  display: inline-flex;
  align-items: center;
  width: fit-content;
  border-radius: 999px;
  padding: 6px 12px;
  background: rgba(56, 189, 248, 0.14);
  border: 1px solid var(--border);
  color: var(--text);
  font-size: 0.85rem;
  font-weight: 700;
}

.lesson-objectives {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 18px 0 4px;
}

.objective-chip {
  background: rgba(34, 197, 94, 0.12);
  border: 1px solid var(--border);
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 0.9rem;
}

.lesson-section,
.challenge-section {
  margin-top: 22px;
}

.lesson-content {
  line-height: 1.75;
}

.lesson-content ul,
.lesson-content ol {
  padding-left: 20px;
}

.code-block {
  background: #020617;
  color: #dbeafe;
  border-radius: 18px;
  padding: 16px;
  overflow-x: auto;
  white-space: pre-wrap;
  line-height: 1.6;
}

.diagram-box {
  background:
    linear-gradient(135deg, rgba(56, 189, 248, 0.08), rgba(167, 139, 250, 0.06)),
    var(--panel-2);
  border-radius: 18px;
  padding: 18px;
  line-height: 1.7;
  font-family: Consolas, Monaco, monospace;
  white-space: pre-wrap;
}

.quiz-container {
  display: grid;
  gap: 18px;
}

.quiz-question-card {
  background: rgba(255,255,255,0.03);
  border-radius: 16px;
  padding: 14px;
  border: 1px solid var(--border);
}

.quiz-question-card h4 {
  margin: 0 0 12px;
}

.quiz-option,
.exam-option {
  display: block;
  width: 100%;
  text-align: left;
  padding: 14px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--panel-2);
  color: var(--text);
  cursor: pointer;
  margin-bottom: 8px;
}

.quiz-option.correct {
  outline: 2px solid var(--accent-2);
}

.quiz-option.wrong {
  outline: 2px solid var(--danger);
}

.quiz-feedback {
  padding: 12px 14px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.04);
  color: var(--muted);
  margin-top: 10px;
}

.quiz-score-box {
  margin-top: 14px;
  background: rgba(255,255,255,0.03);
  border-radius: 14px;
  padding: 14px;
}

.roadmap-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
  margin-top: 18px;
}

.roadmap-card {
  background: var(--panel-2);
  border-radius: 18px;
  padding: 18px;
}

.roadmap-card h3 {
  margin: 0 0 12px;
}

.roadmap-card ul {
  margin: 0;
  padding-left: 18px;
  line-height: 1.8;
  color: var(--muted);
}

.lab-layout {
  display: grid;
  grid-template-columns: 320px 1fr;
  gap: 20px;
  margin-top: 18px;
}

.challenge-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.challenge-item {
  background: var(--panel-2);
  padding: 14px;
  border-radius: 16px;
  cursor: pointer;
}

.challenge-item.active {
  outline: 2px solid var(--accent);
}

.challenge-item h4 {
  margin: 0 0 8px;
}

.challenge-status {
  font-size: 0.85rem;
  color: var(--muted);
}

.challenge-status.done {
  color: var(--accent-2);
  font-weight: 700;
}

.challenge-card {
  background: var(--panel-2);
  padding: 18px;
  border-radius: 20px;
}

.mini-box {
  background: rgba(255, 255, 255, 0.04);
  border-radius: 14px;
  padding: 14px;
  color: var(--muted);
  line-height: 1.7;
}

.project-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  margin-top: 18px;
}

.project-card {
  background: var(--panel-2);
  border-radius: 20px;
  padding: 18px;
}

.project-card h3 {
  margin: 0 0 10px;
}

.project-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
}

.project-tag {
  border-radius: 999px;
  padding: 6px 10px;
  font-size: 0.8rem;
  border: 1px solid var(--border);
  background: rgba(167, 139, 250, 0.12);
}

.project-list {
  padding-left: 18px;
  line-height: 1.75;
  color: var(--muted);
}

.exam-container {
  display: grid;
  gap: 16px;
  margin-top: 18px;
}

.exam-question-card {
  background: var(--panel-2);
  border-radius: 18px;
  padding: 18px;
}

.exam-question-card h4 {
  margin: 0 0 14px;
}

.exam-options {
  display: grid;
  gap: 10px;
}

.exam-actions {
  margin-top: 20px;
}

.exam-result-box {
  margin-top: 16px;
  background: rgba(255, 255, 255, 0.03);
  border-radius: 16px;
  padding: 16px;
}

.exam-side-stats {
  display: flex;
  gap: 12px;
}

.certificate-layout {
  display: grid;
  grid-template-columns: 340px 1fr;
  gap: 20px;
  margin-top: 18px;
}

.certificate-form-card {
  background: var(--panel-2);
  border-radius: 20px;
  padding: 18px;
}

.certificate-preview {
  background:
    linear-gradient(135deg, rgba(56, 189, 248, 0.10), rgba(251, 191, 36, 0.06)),
    var(--panel-2);
  border-radius: 22px;
  padding: 20px;
}

.certificate-inner {
  min-height: 520px;
  border-radius: 22px;
  padding: 18px;
  background:
    linear-gradient(180deg, rgba(255,255,255,0.03), rgba(255,255,255,0.01));
}

.cert-border {
  min-height: 480px;
  border: 2px solid rgba(251, 191, 36, 0.35);
  border-radius: 22px;
  padding: 34px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cert-border::before,
.cert-border::after {
  content: "";
  position: absolute;
  width: 180px;
  height: 180px;
  border-radius: 50%;
  filter: blur(20px);
  opacity: 0.18;
}

.cert-border::before {
  background: var(--accent);
  top: -40px;
  left: -40px;
}

.cert-border::after {
  background: var(--gold);
  bottom: -40px;
  right: -40px;
}

.cert-topline {
  letter-spacing: 4px;
  font-size: 0.88rem;
  color: var(--muted);
  margin-bottom: 12px;
  position: relative;
  z-index: 1;
}

.cert-badge-row {
  display: flex;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 14px;
  position: relative;
  z-index: 1;
}

.cert-badge {
  border-radius: 999px;
  padding: 6px 12px;
  border: 1px solid var(--border);
  background: rgba(255,255,255,0.08);
  font-size: 0.82rem;
}

.certificate-inner h2 {
  margin: 0 0 14px;
  font-size: 2.3rem;
  color: var(--gold);
  position: relative;
  z-index: 1;
}

.certificate-inner h3 {
  font-size: 2.2rem;
  margin: 18px 0;
  color: var(--accent);
  position: relative;
  z-index: 1;
}

.cert-text {
  font-size: 1.05rem;
  color: var(--text);
  line-height: 1.8;
  position: relative;
  z-index: 1;
}

.cert-signature-row {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  margin-top: 26px;
  position: relative;
  z-index: 1;
}

.cert-signature {
  flex: 1;
  text-align: center;
}

.signature-line {
  height: 1px;
  background: rgba(251, 191, 36, 0.45);
  margin-bottom: 10px;
}

.cert-signature span {
  display: block;
  color: var(--muted);
  margin-bottom: 6px;
}

.certificate-metrics {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 18px;
}

.mini-metric {
  background: rgba(255, 255, 255, 0.04);
  border-radius: 14px;
  padding: 14px;
}

.mini-metric span {
  display: block;
  color: var(--muted);
  margin-bottom: 6px;
}

.footer {
  text-align: center;
  margin-top: 24px;
  color: var(--muted);
  font-size: 0.95rem;
  display: flex;
  gap: 14px;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}

.network-footer-links {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

.network-footer-links a {
  color: var(--text);
  text-decoration: none;
}

.network-footer-links a:hover {
  color: var(--accent);
}

.network-footer-label {
  color: var(--muted);
  font-weight: 700;
}

@media (max-width: 1280px) {
  .hero-stats {
    grid-template-columns: repeat(3, 1fr);
  }

  .project-grid,
  .roadmap-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .lab-layout,
  .certificate-layout,
  .main-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    position: relative;
    top: auto;
    max-height: none;
  }
}

@media (max-width: 760px) {
  .topbar,
  .lesson-header,
  .section-header {
    flex-direction: column;
    align-items: stretch;
  }

  .certificate-metrics,
  .project-grid,
  .roadmap-grid,
  .hero-stats {
    grid-template-columns: 1fr;
  }

  .cert-signature-row {
    flex-direction: column;
  }

  .hero-card h2 {
    font-size: 1.5rem;
  }

  .certificate-inner h2 {
    font-size: 1.6rem;
  }

  .certificate-inner h3 {
    font-size: 1.5rem;
  }
}

@media print {
  body * {
    visibility: hidden;
  }

  #certificatePreview,
  #certificatePreview * {
    visibility: visible;
  }

  #certificatePreview {
    position: absolute;
    left: 0;
    top: 0;
    width: 100%;
    box-shadow: none;
    border: none;
    background: white;
    color: black;
    padding: 0;
  }

  .certificate-inner,
  .cert-border {
    background: white !important;
    color: black !important;
    box-shadow: none !important;
  }

  .cert-border {
    min-height: 100vh;
    border: 2px solid #999;
  }
}