/* ===== Tablet ===== */
@media (max-width: 1024px) {
  .lesson-layout { grid-template-columns: 1fr; gap: 0; }
  .lesson-toc { display: none; }
}

/* ===== Mobile ===== */
@media (max-width: 768px) {
  /* Fix backgrounds */
  .bg-image, .bg-glow, .bg-grid, .bg-grain {
    position: fixed; width: 100vw; max-width: 100%;
  }
  .bg-glow { animation: none; }

  /* Nav */
  .nav-links {
    display: none; position: absolute; top: 60px; left: 0; right: 0;
    background: rgba(5,5,5,0.97); backdrop-filter: blur(20px);
    flex-direction: column; padding: 24px; gap: 18px;
    border-bottom: 1px solid var(--bg-glass-border); z-index: 100;
  }
  .nav-links.open { display: flex; }
  .nav-toggle { display: block; }
  .nav-inner { padding: 12px 20px; }

  /* Main content — generous padding on mobile */
  .main-content {
    padding: 84px 20px 50px;
  }

  /* Hero */
  .hero-section { padding: 30px 0 24px; }
  .hero-section h1 { font-size: 32px; }
  .hero-section p { font-size: 15px; padding: 0 8px; }
  .lesson-hero { padding: 40px 8px 30px; }
  .lesson-hero h1 { font-size: 26px; line-height: 1.3; }
  .lesson-hero .lesson-id { font-size: 12px; letter-spacing: 2px; }
  .lesson-hero .lesson-desc { font-size: 14px; padding: 0 8px; }
  .lesson-prereqs { flex-direction: column; align-items: center; gap: 6px; }
  .lesson-prereqs a { font-size: 11px; }

  /* Cards grid */
  .cards-grid { grid-template-columns: 1fr; gap: 10px; }
  .lesson-card { padding: 16px 18px; gap: 12px; border-radius: 14px; }
  .lesson-card .card-num { width: 38px; height: 38px; font-size: 12px; border-radius: 10px; }
  .lesson-card .card-info .card-title { font-size: 15px; }
  .lesson-card .card-info .card-section { font-size: 11px; }
  .section-title { font-size: 12px; margin: 32px 0 14px; }

  /* Layout fix — prevent overflow */
  .lesson-layout { overflow: hidden; }
  .lesson-body { overflow-wrap: break-word; word-wrap: break-word; }

  /* Lesson body text — readable with good margins */
  .lesson-body h2 {
    font-size: 21px; margin: 40px 0 16px;
    padding-bottom: 10px;
  }
  .lesson-body h3 { font-size: 17px; margin: 28px 0 10px; }
  .lesson-body p {
    font-size: 15px; line-height: 1.8;
    margin-bottom: 14px;
  }
  .lesson-body code {
    font-size: 13px; padding: 1px 6px;
  }
  .lesson-body strong { font-weight: 600; }
  .lesson-body ul, .lesson-body ol {
    padding-left: 20px; margin-bottom: 14px;
  }
  .lesson-body li {
    font-size: 15px; line-height: 1.7; margin-bottom: 6px;
  }

  /* Code blocks — scroll, smaller text */
  .code-block { border-radius: 12px; margin: 16px 0; }
  .code-header { padding: 8px 14px; font-size: 12px; }
  .copy-btn { font-size: 11px; padding: 3px 10px; }
  .code-table { font-size: 12px; line-height: 1.6; }
  .code-table td.ln { width: 28px; padding: 1px 10px 1px 10px; font-size: 10px; }
  .code-table td.code-line { padding: 1px 10px 1px 0; }

  /* Terminal blocks */
  .terminal-block { border-radius: 12px; margin: 16px 0; }
  .terminal-header { padding: 10px 14px; }
  .terminal-title { font-size: 12px; }
  .terminal-body {
    font-size: 12px; line-height: 1.8; padding: 14px;
    overflow-x: auto; -webkit-overflow-scrolling: touch;
  }
  .terminal-body .term-line { white-space: pre; }

  /* Diagram blocks */
  .diagram-block { margin: 16px 0; }
  .diagram-block pre {
    font-size: 10px; padding: 14px 18px;
    overflow-x: auto; -webkit-overflow-scrolling: touch;
    border-radius: 12px;
  }

  /* Tables */
  .table-wrap {
    overflow-x: auto; -webkit-overflow-scrolling: touch;
    margin: 16px 0; border-radius: 12px;
    border: 1px solid var(--bg-glass-border);
  }
  .table-wrap table { min-width: 480px; font-size: 13px; }
  .table-wrap th { padding: 8px 12px; font-size: 11px; }
  .table-wrap td { padding: 8px 12px; }

  /* Info cards */
  .info-card { border-radius: 10px; margin: 14px 0; }
  .info-content { padding: 12px 14px; font-size: 14px; line-height: 1.6; }

  /* Concept list */
  .concept-list { flex-direction: column; gap: 8px; margin: 16px 0; }
  .concept-card { padding: 14px 16px; border-radius: 12px; gap: 14px; }
  .concept-card .accent-bar { height: 36px; }
  .concept-card .card-label { font-size: 15px; }
  .concept-card .card-desc { font-size: 12px; }

  /* Video embed */
  .video-embed { border-radius: 12px; margin: 20px 0; }

  /* Nav prev/next */
  .lesson-nav {
    flex-direction: column; gap: 10px;
    margin-top: 40px; padding-top: 24px;
  }
  .lesson-nav a {
    max-width: 100%; padding: 14px 18px; border-radius: 12px;
  }
  .lesson-nav .nav-label { font-size: 11px; }
  .lesson-nav .nav-title { font-size: 14px; }

  /* Quiz */
  .quiz { margin: 36px 0; }
  .quiz-header h2 { font-size: 21px; }
  .quiz-subtitle { font-size: 13px; margin-bottom: 20px; }
  .quiz-question { padding: 16px; border-radius: 12px; margin-bottom: 12px; }
  .quiz-q-header { gap: 10px; margin-bottom: 12px; }
  .quiz-num { width: 28px; height: 28px; font-size: 12px; border-radius: 8px; }
  .quiz-q-text { font-size: 14px; }
  .quiz-choices { gap: 6px; }
  .quiz-choice { padding: 10px 14px; font-size: 13px; border-radius: 10px; }
  .quiz-explain { margin-top: 10px; padding: 10px 12px; border-radius: 8px; }
  .quiz-explain p { font-size: 12px; }
  .quiz-result { font-size: 16px; padding: 16px 20px; border-radius: 12px; }

  /* Footer */
  .main-footer { padding: 24px 20px; margin-top: 50px; }
  .footer-inner { flex-direction: column; gap: 10px; text-align: center; }
  .footer-links { justify-content: center; gap: 20px; }
  .footer-links a { font-size: 12px; }
  .footer-copy { font-size: 12px; }
}

/* ===== Small phones ===== */
@media (max-width: 380px) {
  .main-content { padding: 76px 14px 30px; }
  .hero-section h1 { font-size: 26px; }
  .lesson-hero h1 { font-size: 22px; }
  .lesson-body h2 { font-size: 19px; }
  .lesson-body p { font-size: 14px; }
  .code-pre { font-size: 11px; }
  .terminal-body { font-size: 11px; }
}