/* ===== RESET & BASE ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d0f14;
  --surface:   #13161e;
  --surface2:  #1a1e29;
  --surface3:  #222737;
  --border:    #2a2f42;
  --border2:   #343a52;
  --accent:    #5b8fff;
  --accent2:   #3a6bff;
  --accent-glow: rgba(91,143,255,0.18);
  --green:     #3ecf8e;
  --green-dim: rgba(62,207,142,0.12);
  --yellow:    #f5c842;
  --yellow-dim:rgba(245,200,66,0.12);
  --orange:    #ff7b47;
  --text:      #e8ecf5;
  --text-2:    #9aa3bc;
  --text-3:    #5d6680;
  --mono:      'JetBrains Mono', 'Cascadia Code', 'Fira Code', monospace;
  --sans:      'Inter', system-ui, -apple-system, sans-serif;
  --sidebar-w: 280px;
  --radius:    10px;
  --radius-lg: 14px;
}

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

/* ===== LAYOUT ===== */
.layout {
  display: flex;
  min-height: 100vh;
}

/* ===== SIDEBAR ===== */
.sidebar {
  width: var(--sidebar-w);
  min-height: 100vh;
  background: var(--surface);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 100;
  overflow-y: auto;
  transition: transform 0.28s cubic-bezier(0.4,0,0.2,1);
}

.sidebar-header {
  padding: 22px 20px 16px;
  border-bottom: 1px solid var(--border);
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--accent), var(--accent2));
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  flex-shrink: 0;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.brand-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

.brand-sub {
  font-size: 11px;
  color: var(--text-3);
  font-weight: 500;
}

/* ===== PROGRESS ===== */
.progress-section {
  padding: 16px 20px;
  border-bottom: 1px solid var(--border);
}

.progress-label {
  display: flex;
  justify-content: space-between;
  font-size: 12px;
  color: var(--text-2);
  margin-bottom: 8px;
  font-weight: 500;
}

#progress-pct {
  color: var(--accent);
  font-weight: 600;
}

.progress-track {
  height: 6px;
  background: var(--surface3);
  border-radius: 99px;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--green));
  border-radius: 99px;
  width: 0%;
  transition: width 0.5s cubic-bezier(0.4,0,0.2,1);
}

/* ===== NAV ===== */
.module-nav {
  flex: 1;
  padding: 10px 12px;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 9px 10px;
  border-radius: 8px;
  text-decoration: none;
  color: var(--text-2);
  font-size: 13px;
  font-weight: 500;
  transition: background 0.15s, color 0.15s;
  cursor: pointer;
}

.nav-item:hover {
  background: var(--surface2);
  color: var(--text);
}

.nav-item.active {
  background: var(--accent-glow);
  color: var(--accent);
}

.nav-icon {
  font-size: 15px;
  width: 18px;
  text-align: center;
  flex-shrink: 0;
}

.nav-check {
  font-size: 14px;
  width: 18px;
  text-align: center;
  flex-shrink: 0;
  color: var(--text-3);
  transition: color 0.2s;
}

.nav-check.done {
  color: var(--green);
}

.nav-label {
  line-height: 1.3;
}

/* ===== SIDEBAR FOOTER ===== */
.sidebar-footer {
  padding: 16px 20px;
  border-top: 1px solid var(--border);
}

.reset-btn {
  width: 100%;
  padding: 9px 14px;
  background: transparent;
  border: 1px solid var(--border2);
  border-radius: 8px;
  color: var(--text-3);
  font-size: 13px;
  font-family: var(--sans);
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s, background 0.15s;
  font-weight: 500;
}

.reset-btn:hover {
  border-color: var(--orange);
  color: var(--orange);
  background: rgba(255,123,71,0.06);
}

/* ===== TOPBAR (mobile) ===== */
.topbar {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: 52px;
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  align-items: center;
  padding: 0 16px;
  z-index: 200;
  gap: 12px;
}

.hamburger {
  background: none;
  border: none;
  color: var(--text);
  font-size: 20px;
  cursor: pointer;
  padding: 4px;
  line-height: 1;
}

.topbar-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  flex: 1;
}

.topbar-pct {
  font-size: 13px;
  font-weight: 600;
  color: var(--accent);
}

/* ===== CONTENT ===== */
.content {
  margin-left: var(--sidebar-w);
  flex: 1;
  min-height: 100vh;
}

/* ===== PAGES ===== */
.page {
  display: none;
  padding: 48px 56px 80px;
  max-width: 820px;
  animation: fadeIn 0.25s ease;
}

.page.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* ===== HERO ===== */
.hero {
  margin-bottom: 52px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  background: var(--accent-glow);
  border: 1px solid rgba(91,143,255,0.3);
  color: var(--accent);
  padding: 5px 14px;
  border-radius: 99px;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.03em;
  margin-bottom: 20px;
}

.hero-title {
  font-size: clamp(28px, 4vw, 42px);
  font-weight: 800;
  line-height: 1.15;
  margin-bottom: 18px;
  letter-spacing: -0.02em;
}

.highlight {
  background: linear-gradient(90deg, var(--accent), var(--green));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-tagline {
  font-size: 17px;
  color: var(--text-2);
  max-width: 560px;
  line-height: 1.65;
  margin-bottom: 24px;
}

.hero-formula {
  display: inline-block;
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 20px;
}

.hero-formula code {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--green);
}

/* ===== MODULES GRID ===== */
.modules-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 14px;
  margin-bottom: 40px;
}

.module-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
  cursor: pointer;
  transition: border-color 0.2s, transform 0.15s, box-shadow 0.2s;
}

.module-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.3), 0 0 0 1px var(--accent-glow);
}

.mc-num {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-glow);
  border-radius: 5px;
  padding: 2px 7px;
  margin-bottom: 10px;
  letter-spacing: 0.05em;
}

.module-card h3 {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
  line-height: 1.3;
}

.module-card p {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.5;
}

.module-card p code {
  font-family: var(--mono);
  font-size: 12px;
  background: var(--surface3);
  padding: 1px 5px;
  border-radius: 4px;
  color: var(--accent);
}

/* ===== CONCEPT ROW ===== */
.concept-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.concept-box {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px;
}

.concept-icon {
  font-size: 20px;
  margin-bottom: 8px;
}

.concept-box strong {
  display: block;
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 5px;
}

.concept-box p {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.5;
}

/* ===== MODULE HEADER ===== */
.module-header {
  margin-bottom: 32px;
}

.module-number {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid rgba(91,143,255,0.25);
  border-radius: 5px;
  padding: 3px 9px;
  margin-bottom: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.module-header h2 {
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 14px;
  line-height: 1.2;
}

.module-intro {
  font-size: 16px;
  color: var(--text-2);
  line-height: 1.7;
  max-width: 640px;
}

.module-intro strong {
  color: var(--text);
}

.module-intro code {
  font-family: var(--mono);
  font-size: 14px;
  background: var(--surface3);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--accent);
}

/* ===== INFO BOXES ===== */
.goals-box, .explain-box {
  border-radius: var(--radius);
  padding: 20px 22px;
  margin-bottom: 24px;
}

.goals-box {
  background: var(--green-dim);
  border: 1px solid rgba(62,207,142,0.2);
}

.goals-box h4 {
  font-size: 13px;
  font-weight: 700;
  color: var(--green);
  margin-bottom: 10px;
  letter-spacing: 0.02em;
}

.goals-box ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.goals-box ul li {
  font-size: 14px;
  color: var(--text-2);
  padding-left: 20px;
  position: relative;
  line-height: 1.5;
}

.goals-box ul li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--green);
  font-size: 12px;
}

.explain-box {
  background: var(--surface2);
  border: 1px solid var(--border);
}

.explain-box h4 {
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
  letter-spacing: 0.02em;
}

.explain-box p {
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.65;
  margin-bottom: 8px;
}

.explain-box p:last-child { margin-bottom: 0; }

.explain-box ul, .explain-box ol {
  padding-left: 20px;
  margin-top: 8px;
  display: flex;
  flex-direction: column;
  gap: 5px;
}

.explain-box ul li, .explain-box ol li {
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.5;
}

.explain-box strong { color: var(--text); }

.explain-box code {
  font-family: var(--mono);
  font-size: 13px;
  background: var(--surface3);
  padding: 1px 5px;
  border-radius: 4px;
  color: var(--accent);
}

.explain-box em {
  color: var(--yellow);
  font-style: normal;
}

/* ===== EQUATIONS ===== */
.equation-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
  margin: 14px 0;
}

.eq {
  background: var(--surface3);
  border: 1px solid var(--border2);
  border-radius: 8px;
  padding: 10px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
}

.eq code {
  font-family: var(--mono);
  font-size: 13px;
  color: var(--yellow);
  background: none;
  padding: 0;
  white-space: nowrap;
}

.eq span {
  font-size: 11px;
  color: var(--text-3);
  text-align: right;
  white-space: nowrap;
}

/* ===== FORMULA ROW ===== */
.formula-row {
  display: flex;
  gap: 24px;
  margin: 14px 0;
  flex-wrap: wrap;
}

.formula-row code {
  font-family: var(--mono);
  font-size: 14px;
  color: var(--yellow) !important;
  background: var(--surface3) !important;
  padding: 8px 14px !important;
  border-radius: 8px !important;
}

/* ===== CODE BLOCK ===== */
.code-block-wrap {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-bottom: 24px;
  background: #0a0c12;
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
}

.code-lang {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.copy-btn {
  background: var(--surface3);
  border: 1px solid var(--border2);
  border-radius: 6px;
  color: var(--text-2);
  font-size: 12px;
  font-family: var(--sans);
  font-weight: 600;
  padding: 5px 12px;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
}

.copy-btn:hover {
  background: var(--accent-glow);
  border-color: var(--accent);
  color: var(--accent);
}

.copy-btn.copied {
  background: var(--green-dim);
  border-color: var(--green);
  color: var(--green);
}

.code-block {
  margin: 0;
  padding: 22px 22px;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 13.5px;
  line-height: 1.7;
  color: #c9d1d9;
  background: #0a0c12;
  white-space: pre;
  tab-size: 4;
}

/* Python syntax highlighting — applied by JS highlighter */
.code-block .kw   { color: #c792ea; }
.code-block .fn   { color: #82aaff; }
.code-block .str  { color: #c3e88d; }
.code-block .num  { color: #f78c6c; }
.code-block .cm   { color: #546e7a; font-style: italic; }
.code-block .self { color: #e2b964; }
.code-block .cls  { color: #3ecf8e; }
.code-block .deco { color: #d2a8ff; }

/* ===== CODE USAGE BADGES ===== */
.code-usage-badge {
  padding: 7px 16px;
  font-size: 12px;
  font-weight: 600;
  font-family: var(--sans);
  letter-spacing: 0.02em;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 7px;
}
.badge-replace {
  background: rgba(91,143,255,0.09);
  color: #82aaff;
  border-bottom-color: rgba(91,143,255,0.18);
}
.badge-add {
  background: rgba(62,207,142,0.09);
  color: #3ecf8e;
  border-bottom-color: rgba(62,207,142,0.18);
}
.badge-change {
  background: rgba(245,200,66,0.09);
  color: #f5c842;
  border-bottom-color: rgba(245,200,66,0.18);
}
.badge-ref {
  background: rgba(93,102,128,0.10);
  color: var(--text-3);
  border-bottom-color: var(--border);
}

/* ===== RESPONSIVE VIDEO WRAPPER ===== */
.video-wrap {
  position: relative;
  padding-bottom: 56.25%; /* 16:9 */
  height: 0;
  overflow: hidden;
  border-radius: var(--radius-lg);
  background: #000;
  margin-bottom: 24px;
}
.video-wrap iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%;
  height: 100%;
  border: 0;
  border-radius: var(--radius-lg);
}

/* ===== WORKFLOW NOTE BOX ===== */
.workflow-note-box {
  background: rgba(91,143,255,0.05);
  border: 1px solid rgba(91,143,255,0.18);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 14px 18px 14px 16px;
  margin-bottom: 24px;
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.65;
}
.workflow-note-box strong { color: var(--text); }
.workflow-note-box ul {
  margin-top: 8px;
  padding-left: 18px;
}
.workflow-note-box li { margin-bottom: 4px; }

/* ===== WIRING DIAGRAM ===== */
.wiring-diagram {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px 22px 16px;
  margin-bottom: 24px;
}

.wiring-diagram-title {
  font-size: 12px;
  font-weight: 700;
  color: var(--text-3);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 14px;
}

.wiring-svg {
  width: 100%;
  height: auto;
  display: block;
  overflow: visible;
}

.wd-board-label {
  font-family: var(--sans);
  font-size: 10px;
  font-weight: 700;
  fill: var(--text-2);
  letter-spacing: 0.03em;
}

.wd-pin-label {
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 600;
}

.wd-pin-small {
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 600;
}

.wd-wire-label {
  font-family: var(--sans);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.wd-motor-m {
  font-family: var(--sans);
  font-size: 22px;
  font-weight: 800;
  fill: var(--text);
}

.wiring-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
}

.wl-item {
  display: flex;
  align-items: center;
  gap: 7px;
  font-size: 12px;
  color: var(--text-2);
  line-height: 1.4;
}

.wl-dot {
  flex-shrink: 0;
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.wiring-note {
  margin-top: 10px;
  font-size: 12px;
  color: var(--text-3);
  line-height: 1.55;
}

/* ===== CHALLENGE BOX ===== */
.challenge-box {
  background: var(--yellow-dim);
  border: 1px solid rgba(245,200,66,0.2);
  border-radius: var(--radius);
  padding: 20px 22px;
  margin-bottom: 30px;
}

.challenge-box h4 {
  font-size: 13px;
  font-weight: 700;
  color: var(--yellow);
  margin-bottom: 8px;
  letter-spacing: 0.02em;
}

.challenge-box p {
  font-size: 14px;
  color: var(--text-2);
  line-height: 1.65;
}

.challenge-box code {
  font-family: var(--mono);
  font-size: 13px;
  background: rgba(255,255,255,0.06);
  padding: 1px 6px;
  border-radius: 4px;
  color: var(--yellow);
}

/* ===== EXPLANATION LEVELS ===== */
.level-label {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 3px 9px;
  border-radius: 999px;
  margin-bottom: 10px;
  background: rgba(74,222,128,0.12);
  color: #4ade80;
  border: 1px solid rgba(74,222,128,0.25);
}

.level-basic {
  border-left: 3px solid #4ade80;
}

.level-inter {
  border-left: 3px solid #fb923c;
}

.level-inter .level-label {
  background: rgba(251,146,60,0.12);
  color: #fb923c;
  border-color: rgba(251,146,60,0.25);
}

/* ===== COURSE IMAGES ===== */
.course-fig {
  margin: 16px auto;
  text-align: center;
}

.course-img {
  width: 100%;
  border-radius: var(--radius);
  display: block;
  margin: 0 auto;
}

.course-fig-cap {
  margin-top: 7px;
  font-size: 12px;
  color: var(--text-3);
  font-style: italic;
}

.course-fig-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 16px 0;
}

@media (max-width: 600px) {
  .course-fig-pair {
    grid-template-columns: 1fr;
  }
}

/* ===== SYMBOL KEY ===== */
.symbol-key {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  margin-bottom: 16px;
  overflow: hidden;
}

.symbol-key-summary {
  cursor: pointer;
  padding: 12px 16px;
  font-size: 13px;
  font-weight: 600;
  color: var(--text-2);
  list-style: none;
  user-select: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.symbol-key-summary::-webkit-details-marker { display: none; }

.symbol-key[open] .symbol-key-summary {
  border-bottom: 1px solid var(--border);
  color: var(--text);
}

.symbol-key-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

/* ===== COMPLETION ROW ===== */
.completion-row {
  display: flex;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
  padding: 20px 0 0;
  border-top: 1px solid var(--border);
}

.checkbox-label {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
  user-select: none;
  font-size: 14px;
  font-weight: 600;
  color: var(--text-2);
  transition: color 0.2s;
}

.checkbox-label:hover {
  color: var(--text);
}

.checkbox-label input[type="checkbox"] {
  display: none;
}

.checkmark {
  width: 20px;
  height: 20px;
  border: 2px solid var(--border2);
  border-radius: 5px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, border-color 0.2s;
  flex-shrink: 0;
  font-size: 12px;
}

.checkbox-label input:checked ~ .checkmark {
  background: var(--green);
  border-color: var(--green);
}

.checkbox-label input:checked ~ .checkmark::after {
  content: "✓";
  color: #0d0f14;
  font-weight: 800;
  line-height: 1;
}

.checkbox-label input:checked ~ span:not(.checkmark) {
  color: var(--green);
}

.next-btn {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 8px;
  color: var(--text-2);
  font-size: 13px;
  font-family: var(--sans);
  font-weight: 600;
  padding: 8px 16px;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s, background 0.15s;
}

.next-btn:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-glow);
}

/* ===== FINISH BANNER ===== */
.finish-banner {
  display: none;
  text-align: center;
  background: linear-gradient(135deg, rgba(62,207,142,0.08), rgba(91,143,255,0.08));
  border: 1px solid rgba(62,207,142,0.25);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  margin-top: 32px;
}

.finish-banner.visible {
  display: block;
  animation: fadeIn 0.4s ease;
}

.finish-icon {
  font-size: 42px;
  margin-bottom: 12px;
}

.finish-banner h3 {
  font-size: 22px;
  font-weight: 800;
  color: var(--text);
  margin-bottom: 10px;
}

.finish-banner p {
  font-size: 15px;
  color: var(--text-2);
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.65;
}

/* ===== SIDEBAR OVERLAY ===== */
.sidebar-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  z-index: 90;
}

.sidebar-overlay.visible { display: block; }

/* ===== RESPONSIVE ===== */
@media (max-width: 900px) {
  .page { padding: 40px 36px 60px; }
  .concept-row { grid-template-columns: 1fr; }
  .equation-grid { grid-template-columns: 1fr; }
}

@media (max-width: 700px) {
  .topbar { display: flex; }

  .sidebar {
    transform: translateX(-100%);
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .content {
    margin-left: 0;
    padding-top: 52px;
  }

  .page {
    padding: 28px 20px 60px;
  }

  .hero-title { font-size: 26px; }
  .modules-grid { grid-template-columns: 1fr; }

  .completion-row {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }

  .formula-row { flex-direction: column; gap: 10px; }
  .eq { flex-direction: column; align-items: flex-start; gap: 4px; }
}

@media (max-width: 480px) {
  .page { padding: 20px 16px 60px; }
  .hero-formula { overflow-x: auto; max-width: 100%; }
  .hero-formula code { font-size: 12px; white-space: nowrap; }
}

/* ===== NAV SEPARATOR ===== */
.nav-sep { height: 1px; background: var(--border); margin: 6px 12px 4px; }

/* ===== REFERENCE CARD BADGE ===== */
.mc-ref { color: #94a3b8; background: rgba(93,102,128,0.15); }

/* ===== WIRING REFERENCE PAGE ===== */
.wiring-subsec { margin-bottom: 38px; }

.wiring-subsec-title {
  font-size: 11px; font-weight: 700; color: var(--text-3);
  letter-spacing: 0.08em; text-transform: uppercase;
  padding-bottom: 8px; margin-bottom: 14px;
  border-bottom: 1px solid var(--border);
}

/* ===== PIN TABLE ===== */
.pin-table {
  width: 100%; border-collapse: collapse; font-size: 13px; margin-bottom: 4px;
  border: 1px solid var(--border); border-radius: var(--radius); overflow: hidden;
}
.pin-table th {
  font-size: 11px; font-weight: 700; color: var(--text-3);
  text-transform: uppercase; letter-spacing: 0.06em; text-align: left;
  padding: 8px 12px; background: var(--surface3); border-bottom: 1px solid var(--border2);
}
.pin-table td {
  padding: 9px 12px; color: var(--text-2);
  border-bottom: 1px solid var(--border); vertical-align: middle; line-height: 1.4;
}
.pin-table tr:last-child td { border-bottom: none; }
.pin-table tbody tr:hover td { background: rgba(255,255,255,0.018); }
.pin-table code {
  font-family: var(--mono); font-size: 12px; background: var(--surface3);
  padding: 1px 5px; border-radius: 4px; color: var(--text);
}
.t-in1  { color: #5b8fff; font-family: var(--mono); font-size: 12px; font-weight: 700; }
.t-in2  { color: #3ecf8e; font-family: var(--mono); font-size: 12px; font-weight: 700; }
.t-i2c  { color: #22d3ee; font-family: var(--mono); font-size: 12px; font-weight: 700; }
.t-uart { color: #c084fc; font-family: var(--mono); font-size: 12px; font-weight: 700; }
.t-pwr  { color: #fb923c; font-family: var(--mono); font-size: 12px; font-weight: 700; }
.t-gnd  { color: #94a3b8; font-family: var(--mono); font-size: 12px; font-weight: 700; }
.t-loc  { font-size: 12px; font-weight: 600; color: var(--text); }

/* ===== POWER WARNING ===== */
.power-warning {
  background: rgba(255,123,71,0.07); border: 1px solid rgba(255,123,71,0.28);
  border-left: 3px solid var(--orange); border-radius: var(--radius);
  padding: 14px 18px; margin-bottom: 24px; font-size: 13.5px;
  color: var(--text-2); line-height: 1.7;
}
.power-warning strong { color: #ff7b47; }
.power-warning ul { margin-top: 8px; padding-left: 18px; }
.power-warning li { margin-bottom: 3px; }

/* ===== WIRING NOTE CARDS ===== */
.wiring-notes-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(190px, 1fr));
  gap: 12px; margin-bottom: 28px;
}
.wiring-note-card {
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 16px;
}
.wiring-note-card h5 {
  font-size: 11px; font-weight: 700; color: var(--accent);
  text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 7px;
}
.wiring-note-card p { font-size: 13px; color: var(--text-2); line-height: 1.55; }
.wiring-note-card code {
  font-family: var(--mono); font-size: 12px; background: var(--surface3);
  padding: 1px 5px; border-radius: 4px; color: var(--text);
}

/* ===== SVG WIRING ELEMENT CLASSES ===== */
.wsvg-mnum   { font-size: 14px; font-weight: 800; fill: #e8ecf5; }
.wsvg-msub   { font-size: 8px;  fill: #9aa3bc; }
.wsvg-lbl    { font-size: 9.5px; font-weight: 700; fill: #e8ecf5; }
.wsvg-note   { font-size: 8px;  fill: #5d6680; }
.wsvg-in1    { font-size: 9px;  font-weight: 600; fill: #5b8fff; }
.wsvg-in2    { font-size: 9px;  font-weight: 600; fill: #3ecf8e; }
.wsvg-out    { font-size: 9px;  font-weight: 600; fill: #e2b964; }
.wsvg-gnd    { font-size: 9px;  font-weight: 600; fill: #636e82; }
.wsvg-vm     { font-size: 9px;  font-weight: 600; fill: #ff7b47; }
.wsvg-i2c    { font-size: 9px;  font-weight: 600; fill: #22d3ee; }
.wsvg-uart   { font-size: 9px;  font-weight: 600; fill: #c084fc; }
.wsvg-3v3    { font-size: 9px;  font-weight: 600; fill: #fb923c; }
.wsvg-drv-label { font-size: 9px; fill: #9aa3bc; }
.wsvg-motor-loc { font-size: 8px; fill: #9aa3bc; }
.wsvg-front  { font-size: 10px; font-weight: 700; fill: #5b8fff; }
.wsvg-pin-ext { font-size: 9px; font-weight: 600; fill: #e8ecf5; }

/* ===== OMNI MOTOR LAYOUT DIAGRAM ===== */
.omni-layout-wrap {
  display: flex; flex-direction: column; align-items: center;
  margin: 20px 0 32px; padding: 24px 20px 20px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: var(--radius);
}
.omni-layout-title {
  font-size: 11px; font-weight: 700; color: var(--text-2);
  text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 14px;
}
.omni-layout-fig { max-width: 320px; width: 100%; }
.omni-layout-fig svg { width: 100%; height: auto; display: block; }
.omni-layout-caption {
  margin-top: 12px; font-size: 12px; color: var(--text-2);
  text-align: center; max-width: 380px; line-height: 1.55;
}
.omni-layout-callout {
  display: flex; align-items: center; gap: 18px;
  padding: 14px 18px; margin: 20px 0 24px;
  background: var(--surface2); border: 1px solid var(--border);
  border-left: 3px solid var(--accent); border-radius: var(--radius);
}
.omni-layout-callout .omni-layout-fig { max-width: 150px; flex-shrink: 0; }
.omni-layout-callout-text { font-size: 13px; color: var(--text-2); line-height: 1.6; }
.omni-layout-callout-text strong { color: var(--text); }
@media (max-width: 500px) {
  .omni-layout-callout { flex-direction: column; gap: 12px; }
  .omni-layout-callout .omni-layout-fig { max-width: 200px; }
}

/* ===== COURSE HUB LANDING PAGE ===== */
.hub-screen {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg);
  padding: 48px 24px;
}

.hub-inner {
  max-width: 920px;
  width: 100%;
}

.hub-header {
  text-align: center;
  margin-bottom: 52px;
}

.hub-academy-badge {
  display: inline-block;
  background: rgba(91,143,255,0.10);
  border: 1px solid rgba(91,143,255,0.22);
  border-radius: 100px;
  padding: 5px 16px;
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.hub-title {
  font-size: clamp(30px, 5.5vw, 50px);
  font-weight: 800;
  color: var(--text);
  letter-spacing: -0.025em;
  margin-bottom: 14px;
  line-height: 1.08;
}

.hub-title em {
  font-style: normal;
  color: var(--accent);
}

.hub-subtitle {
  font-size: 16px;
  color: var(--text-2);
  max-width: 400px;
  margin: 0 auto;
  line-height: 1.65;
}

.hub-cards {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.hub-card {
  background: var(--surface);
  border: 1.5px solid var(--border);
  border-radius: 20px;
  padding: 38px 32px 32px;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  position: relative;
  overflow: hidden;
  user-select: none;
}

.hub-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  border-radius: 20px 20px 0 0;
}

.hub-card--omni::before {
  background: linear-gradient(90deg, #5b8fff, #22d3ee);
}

.hub-card--maze::before {
  background: linear-gradient(90deg, #ff7b47, #facc15);
}

.hub-card:hover {
  transform: translateY(-5px);
}

.hub-card--omni:hover {
  border-color: rgba(91,143,255,0.45);
  box-shadow: 0 24px 64px rgba(91,143,255,0.14);
}

.hub-card--maze:hover {
  border-color: rgba(255,123,71,0.45);
  box-shadow: 0 24px 64px rgba(255,123,71,0.14);
}

.hub-card-count {
  position: absolute;
  top: 22px; right: 22px;
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  color: var(--text-3);
}

.hub-card-icon {
  font-size: 44px;
  line-height: 1;
  margin-bottom: 20px;
}

.hub-card-title {
  font-size: 22px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 10px;
  letter-spacing: -0.01em;
}

.hub-card-desc {
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.68;
  margin-bottom: 22px;
}

.hub-card-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-bottom: 26px;
}

.hub-pill {
  font-size: 11px;
  font-weight: 600;
  padding: 3px 10px;
  border-radius: 100px;
}

.hub-card--omni .hub-pill {
  background: rgba(91,143,255,0.12);
  color: #82aaff;
  border: 1px solid rgba(91,143,255,0.20);
}

.hub-card--maze .hub-pill {
  background: rgba(255,123,71,0.12);
  color: #fdba74;
  border: 1px solid rgba(255,123,71,0.20);
}

.hub-card-cta {
  font-size: 14px;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 5px;
}

.hub-card--omni .hub-card-cta { color: var(--accent); }
.hub-card--maze .hub-card-cta { color: #ff7b47; }

@media (max-width: 640px) {
  .hub-cards { grid-template-columns: 1fr; }
  .hub-card { padding: 30px 24px 26px; }
}

/* ===== HUB BACK BUTTON (sidebar) ===== */
.hub-back-wrap {
  padding: 8px 12px 4px;
  border-bottom: 1px solid var(--border);
}

.hub-back-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-3);
  text-decoration: none;
  padding: 7px 10px;
  border-radius: 8px;
  transition: background 0.15s, color 0.15s;
}

.hub-back-btn:hover {
  background: var(--surface3);
  color: var(--text-2);
}

/* Back button in topbar (mobile) */
.hub-back-topbar {
  margin-left: auto;
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 7px;
  color: var(--text-2);
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 600;
  padding: 5px 10px;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
  flex-shrink: 0;
}

.hub-back-topbar:hover {
  border-color: var(--accent);
  color: var(--accent);
}

/* ===== MAZE COURSE ACCENT ===== */
.maze-brand-icon {
  background: linear-gradient(135deg, #ff7b47, #e63b00) !important;
}

.mod-badge--maze {
  background: rgba(255,123,71,0.12);
  color: #ff7b47;
  border: 1px solid rgba(255,123,71,0.25);
}

#maze-course .nav-item.active {
  background: rgba(255,123,71,0.12);
  color: #ff7b47;
}

#maze-course .progress-fill {
  background: linear-gradient(90deg, #ff7b47, #facc15);
}

/* Python phase cards */
.phase-block {
  margin-bottom: 36px;
}

.phase-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 18px;
  padding: 14px 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
}

#maze-course .phase-header {
  border-left-color: #ff7b47;
}

.phase-num {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
  flex-shrink: 0;
}

.phase-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
}

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

.stage-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.stage-header {
  padding: 14px 18px 12px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.stage-num {
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-3);
  flex-shrink: 0;
}

.stage-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
}

.stage-body {
  padding: 14px 18px;
}

.stage-body p {
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.65;
  margin-bottom: 12px;
}

.stage-body p:last-child { margin-bottom: 0; }

/* Checklist styles */
.checklist-group {
  margin-bottom: 28px;
}

.checklist-group-title {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.checklist-items {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.55;
}

.check-box {
  width: 17px;
  height: 17px;
  border: 1.5px solid var(--border2);
  border-radius: 4px;
  flex-shrink: 0;
  margin-top: 2px;
}

/* Resource cards */
.resource-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 14px;
}

.resource-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 20px;
  text-decoration: none;
  transition: border-color 0.15s, background 0.15s;
}

.resource-card:hover {
  border-color: var(--border2);
  background: var(--surface2);
}

.resource-card-title {
  font-size: 14px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}

.resource-card-desc {
  font-size: 12.5px;
  color: var(--text-3);
  line-height: 1.5;
}

.resource-ext {
  font-size: 10px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-3);
  margin-top: 8px;
}

/* Victim colour chips */
.victim-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(180px, 1fr));
  gap: 12px;
  margin: 16px 0;
}

.victim-chip {
  border-radius: var(--radius);
  padding: 14px 16px;
  border: 1px solid var(--border);
}

.victim-chip-label {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.07em;
  text-transform: uppercase;
  margin-bottom: 4px;
}

.victim-chip-desc {
  font-size: 12.5px;
  color: var(--text-2);
  line-height: 1.5;
}

.victim-chip--unharmed {
  background: rgba(62,207,142,0.08);
  border-color: rgba(62,207,142,0.25);
}
.victim-chip--unharmed .victim-chip-label { color: var(--green); }

.victim-chip--harmed {
  background: rgba(255,123,71,0.08);
  border-color: rgba(255,123,71,0.25);
}
.victim-chip--harmed .victim-chip-label { color: #ff7b47; }

.victim-chip--dead {
  background: rgba(148,163,184,0.06);
  border-color: rgba(148,163,184,0.15);
}
.victim-chip--dead .victim-chip-label { color: var(--text-3); }

.victim-chip--silver {
  background: rgba(148,163,184,0.10);
  border-color: rgba(148,163,184,0.25);
}
.victim-chip--silver .victim-chip-label { color: #94a3b8; }

/* ===== MISSING UTILITY CLASSES (shared by maze + omni) ===== */

/* Section heading */
.section-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.01em;
  margin-bottom: 16px;
  margin-top: 8px;
}

/* Module badge (replaces .module-number / .mc-num for maze) */
.mod-badge {
  display: inline-block;
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-glow);
  border: 1px solid rgba(91,143,255,0.25);
  border-radius: 5px;
  padding: 3px 9px;
  margin-bottom: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

/* Module title + subtitle (used inside .module-header) */
.mod-title {
  font-size: clamp(22px, 3vw, 30px);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 10px;
  line-height: 1.2;
  color: var(--text);
}

.mod-subtitle {
  font-size: 15px;
  color: var(--text-2);
  line-height: 1.65;
  max-width: 600px;
}

/* Module grid (alias for .modules-grid) */
.module-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 14px;
  margin-bottom: 32px;
}

/* Module card sub-elements */
.module-card-header { margin-bottom: 8px; }

.module-card-title {
  font-size: 14px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 6px;
  line-height: 1.3;
}

.module-card-desc {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.5;
}

/* Navigation buttons row */
.nav-btns {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  padding: 24px 0 8px;
  border-top: 1px solid var(--border);
  margin-top: 32px;
}

/* Previous-page button */
.prev-btn {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 8px;
  color: var(--text-3);
  font-size: 13px;
  font-family: var(--sans);
  font-weight: 600;
  padding: 8px 16px;
  cursor: pointer;
  transition: border-color 0.15s, color 0.15s;
}

.prev-btn:hover {
  border-color: var(--border2);
  color: var(--text-2);
}

/* Warning / caution box */
.warn-box {
  background: rgba(255,123,71,0.07);
  border: 1px solid rgba(255,123,71,0.25);
  border-left: 3px solid var(--orange);
  border-radius: var(--radius);
  padding: 14px 18px;
  margin-bottom: 24px;
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.65;
}

.warn-box strong { color: #ff7b47; }

/* Table wrapper */
.table-wrap {
  width: 100%;
  overflow-x: auto;
  margin-bottom: 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.table-wrap table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
}

.table-wrap th {
  font-size: 11px;
  font-weight: 700;
  color: var(--text-3);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  text-align: left;
  padding: 9px 14px;
  background: var(--surface3);
  border-bottom: 1px solid var(--border2);
}

.table-wrap td {
  padding: 9px 14px;
  color: var(--text-2);
  border-bottom: 1px solid var(--border);
  vertical-align: middle;
  line-height: 1.45;
}

.table-wrap tr:last-child td { border-bottom: none; }
.table-wrap tbody tr:hover td { background: rgba(255,255,255,0.018); }

.table-wrap code {
  font-family: var(--mono);
  font-size: 12px;
  background: var(--surface3);
  padding: 1px 5px;
  border-radius: 4px;
  color: var(--text);
}

/* Info grid (4-up card grid) */
.info-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 14px;
  margin-bottom: 28px;
}

.info-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 18px 18px 16px;
}

.info-card-title {
  font-size: 13px;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 8px;
  line-height: 1.3;
}

.info-card-body {
  font-size: 13px;
  color: var(--text-2);
  line-height: 1.6;
}

/* Tip list */
.tip-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 28px;
}

.tip-item {
  display: flex;
  align-items: flex-start;
  gap: 14px;
  font-size: 13.5px;
  color: var(--text-2);
  line-height: 1.6;
}

.tip-num {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--accent-glow);
  border: 1px solid rgba(91,143,255,0.25);
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.tip-item strong { color: var(--text); }

/* Code block aliases */
.code-block-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 16px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
}

.code-label {
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 600;
  color: var(--text-3);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}


/* ── Maze Asset Galleries ────────────────────────────────── */
.maze-gallery {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}
.maze-fig {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}
.maze-fig img {
  width: 100%;
  height: auto;
  display: block;
  object-fit: contain;
  background: #111827;
}
.maze-fig figcaption {
  padding: .45rem .75rem;
  font-size: .76rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  line-height: 1.4;
}
.maze-fig--wide { grid-column: 1 / -1; }
.maze-gallery--2col { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.maze-gallery--3col { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }
.maze-solo-img {
  width: 100%;
  max-width: 720px;
  height: auto;
  border-radius: 10px;
  border: 1px solid var(--border);
  display: block;
  margin: 1.25rem 0;
  background: #111827;
}

/* ── SPIKE Prime Line Following Course ───────────────────── */
.hub-card--line::before {
  background: linear-gradient(90deg, #22c55e, #16a34a);
}
.hub-card--line:hover {
  border-color: rgba(34,197,94,.27);
  box-shadow: 0 8px 32px rgba(34,197,94,.14);
}
.hub-card--line .hub-pill {
  background: rgba(34,197,94,.12);
  color: #22c55e;
  border: 1px solid rgba(34,197,94,.3);
}
.hub-card--line .hub-card-cta { color: #22c55e; }

.line-brand-icon { color: #22c55e; }

.mod-badge--line {
  background: rgba(34,197,94,.15);
  color: #22c55e;
  border: 1px solid rgba(34,197,94,.35);
}

#line-course .nav-item.active {
  background: rgba(34,197,94,.12);
  border-left: 3px solid #22c55e;
  color: #22c55e;
}
#line-course .progress-fill {
  background: linear-gradient(90deg, #22c55e, #16a34a);
}

.teach-box {
  background: rgba(34,197,94,.08);
  border-left: 3px solid #22c55e;
  border-radius: 0 10px 10px 0;
  padding: 1rem 1.25rem;
  margin: 1.25rem 0;
  color: var(--text-2);
  font-size: .95rem;
  line-height: 1.65;
}
.teach-box strong { color: #22c55e; }
.teach-box code {
  font-family: var(--mono);
  font-size: .86em;
  background: rgba(34,197,94,.12);
  padding: 1px 5px;
  border-radius: 4px;
  color: #22c55e;
}

.sensor-demo {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 1.25rem 0;
}
.sensor-chip {
  flex: 1 1 120px;
  border-radius: 10px;
  padding: .85rem 1rem;
  text-align: center;
  border: 1px solid var(--border);
  background: var(--card-bg);
}
.sensor-chip__label {
  font-size: .78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .07em;
  color: var(--text-muted);
  margin-bottom: .35rem;
}
.sensor-chip__value {
  font-size: 1.6rem;
  font-weight: 700;
  font-family: var(--mono);
}
.sensor-chip--white  { border-color: rgba(255,255,255,.25); }
.sensor-chip--white  .sensor-chip__value { color: #f1f5f9; }
.sensor-chip--edge   { border-color: rgba(34,197,94,.4);  }
.sensor-chip--edge   .sensor-chip__value { color: #22c55e; }
.sensor-chip--black  { border-color: rgba(100,100,120,.5);}
.sensor-chip--black  .sensor-chip__value { color: #94a3b8; }

/* ── RGB sensor chip colour variants ─────────────────────── */
.sensor-chip--red  { border-color: rgba(239,68,68,.4); }
.sensor-chip--red  .sensor-chip__value { color: #ef4444; }
.sensor-chip--green { border-color: rgba(34,197,94,.4); }
.sensor-chip--green .sensor-chip__value { color: #22c55e; }
.sensor-chip--blue  { border-color: rgba(96,165,250,.4); }
.sensor-chip--blue  .sensor-chip__value { color: #60a5fa; }

.rule-table { width: 100%; border-collapse: collapse; margin: 1rem 0; font-size: .93rem; }
.rule-table th { background: rgba(34,197,94,.12); color: #22c55e; font-weight: 600;
  padding: .6rem .85rem; text-align: left; border-bottom: 1px solid rgba(34,197,94,.25); }
.rule-table td { padding: .55rem .85rem; border-bottom: 1px solid var(--border); color: var(--text-2); }
.rule-table tr:last-child td { border-bottom: none; }
.rule-table .tag-l { color: #22c55e; font-weight: 600; }
.rule-table .tag-r { color: #60a5fa; font-weight: 600; }
.rule-table .tag-s { color: var(--text-muted); font-weight: 600; }

.tuning-table { width: 100%; border-collapse: collapse; margin: 1rem 0; font-size: .91rem; }
.tuning-table th { background: rgba(34,197,94,.10); color: #22c55e; font-weight: 600;
  padding: .55rem .8rem; text-align: left; border-bottom: 1px solid rgba(34,197,94,.2); }
.tuning-table td { padding: .5rem .8rem; border-bottom: 1px solid var(--border); color: var(--text-2);
  vertical-align: top; }
.tuning-table tr:last-child td { border-bottom: none; }
.tuning-table code { font-family: var(--mono); font-size: .85em;
  background: rgba(34,197,94,.1); padding: 1px 5px; border-radius: 4px; color: #22c55e; }

/* ===== MAGIC STRING ROBOT COURSE ===== */
.hub-card--magic::before {
  background: linear-gradient(135deg, #a855f7, #7c3aed);
}
.hub-card--magic:hover {
  box-shadow: 0 8px 40px rgba(168,85,247,0.22);
  border-color: #a855f7;
}
.hub-card--magic .hub-pill {
  background: rgba(168,85,247,0.14);
  color: #c084fc;
  border: 1px solid rgba(168,85,247,0.3);
}
.hub-card--magic .hub-card-cta { color: #a855f7; }

.mod-badge--magic {
  background: rgba(168,85,247,0.15);
  color: #c084fc;
  border: 1px solid rgba(168,85,247,0.35);
  display: inline-block;
  padding: 3px 10px;
  border-radius: 6px;
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ===== ROBOT SIMULATOR HUB CARD ===== */
.hub-card--sim {
  text-decoration: none;
  color: inherit;
  display: block;
  grid-column: 1 / -1;
}
.hub-card--sim::before {
  background: linear-gradient(90deg, #06b6d4, #3b82f6);
}
.hub-card--sim:hover {
  border-color: rgba(6,182,212,0.45);
  box-shadow: 0 24px 64px rgba(6,182,212,0.14);
}
.hub-card--sim .hub-pill {
  background: rgba(6,182,212,0.12);
  color: #67e8f9;
  border: 1px solid rgba(6,182,212,0.22);
}
.hub-card--sim .hub-card-cta { color: #06b6d4; }

/* ===== SIMULATOR CTA BLOCK (in-course link) ===== */
.sim-cta-block {
  margin: 28px 0 24px;
}
.sim-link-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 22px;
  background: rgba(6,182,212,0.10);
  border: 1.5px solid rgba(6,182,212,0.30);
  border-radius: 10px;
  color: #67e8f9;
  font-size: 14px;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.15s, border-color 0.15s, transform 0.15s;
  font-family: var(--sans);
}
.sim-link-btn:hover {
  background: rgba(6,182,212,0.18);
  border-color: rgba(6,182,212,0.55);
  transform: translateY(-1px);
}

.magic-brand-icon {
  background: linear-gradient(135deg, #a855f7, #7c3aed) !important;
}