/* ============================================
   NeuroAI Academy — Dark Mode Design
   ============================================ */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #0d0d0f;
  --bg-card:   #141418;
  --bg-hover:  #1a1a20;
  --border:    #2a2a35;
  --text:      #e8e8f0;
  --text-muted: #888899;
  --accent:    #7c6fff;
  --accent-2:  #5fbfff;
  --accent-3:  #ff7c6e;
  --featured:  rgba(124, 111, 255, 0.08);
  --radius:    12px;
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-serif: 'Crimson Pro', Georgia, serif;
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }

/* ---- NAV ---- */
nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(13, 13, 15, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-weight: 600;
  font-size: 0.95rem;
  letter-spacing: -0.01em;
  color: var(--text);
}

.nav-links {
  display: flex;
  gap: 2rem;
  align-items: center;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.nav-links a:hover { color: var(--text); }

.nav-brain {
  color: var(--accent) !important;
  font-weight: 500;
}

/* ---- HERO ---- */
.hero {
  position: relative;
  padding: 140px 2rem 100px;
  overflow: hidden;
}

.hero-inner {
  max-width: 700px;
  margin: 0 auto;
  text-align: center;
  position: relative;
  z-index: 2;
}

.hero-badge {
  display: inline-block;
  font-size: 0.8rem;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 14px;
  margin-bottom: 2rem;
  letter-spacing: 0.02em;
}

h1 {
  font-family: var(--font-serif);
  font-size: clamp(2.8rem, 6vw, 4.5rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
  color: var(--text);
  margin-bottom: 1.5rem;
}

h1 em {
  font-style: italic;
  color: var(--accent);
}

.hero-sub {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 2.5rem;
}

.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.btn-primary {
  background: var(--accent);
  color: white;
  font-weight: 600;
  font-size: 0.9rem;
  padding: 12px 28px;
  border-radius: var(--radius);
  transition: opacity 0.15s, transform 0.15s;
}

.btn-primary:hover { opacity: 0.88; transform: translateY(-1px); }

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  font-size: 0.9rem;
  padding: 12px 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  transition: border-color 0.15s, color 0.15s;
}

.btn-ghost:hover { border-color: var(--text-muted); color: var(--text); }

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% -10%, rgba(124,111,255,0.12) 0%, transparent 70%),
    radial-gradient(ellipse 60% 40% at 80% 80%, rgba(95,191,255,0.06) 0%, transparent 60%);
  z-index: 1;
  pointer-events: none;
}

/* ---- SECTIONS ---- */
.section-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

.paths { padding: 80px 0; }

h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.section-sub {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 3rem;
}

/* ---- PATH CARDS ---- */
.path-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.5rem;
}

.path-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
  transition: border-color 0.2s, transform 0.2s;
}

.path-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
}

.path-card.featured {
  background: var(--featured);
  border-color: rgba(124, 111, 255, 0.35);
}

.path-card.featured:hover {
  border-color: var(--accent);
}

.path-header {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.path-num {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.08em;
}

.path-tag {
  font-size: 0.72rem;
  color: var(--text-muted);
  background: rgba(255,255,255,0.05);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px 10px;
  letter-spacing: 0.04em;
}

.path-card h3 {
  font-family: var(--font-serif);
  font-size: 1.7rem;
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.02em;
}

.path-card p {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.65;
  flex: 1;
}

.path-topics {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.path-topics li::before {
  content: "→ ";
  color: var(--accent);
  font-size: 0.8rem;
}

.path-topics a {
  font-size: 0.875rem;
  color: var(--text-muted);
  transition: color 0.15s;
}

.path-topics a:hover { color: var(--text); }

.path-cta {
  display: inline-block;
  margin-top: 0.5rem;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  transition: opacity 0.15s;
}

.path-cta:hover { opacity: 0.75; }

/* ---- ABOUT ---- */
.about {
  padding: 80px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.about-inner {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 4rem;
  align-items: center;
}

.about-text p {
  color: var(--text-muted);
  margin-bottom: 1rem;
  font-size: 0.95rem;
  line-height: 1.75;
  max-width: 540px;
}

.about-text h2 { margin-bottom: 1.25rem; }
.about-text .btn-ghost { margin-top: 1rem; display: inline-block; }

.about-stats {
  display: flex;
  flex-direction: column;
  gap: 2rem;
  text-align: right;
}

.stat-num {
  display: block;
  font-family: var(--font-serif);
  font-size: 3rem;
  font-weight: 600;
  color: var(--accent);
  line-height: 1;
}

.stat-label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-top: 0.25rem;
}

/* ---- FOOTER ---- */
footer {
  padding: 2rem 0;
}

.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-muted);
}

.footer-links {
  display: flex;
  gap: 1.5rem;
}

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

/* ---- FEATURED PATH ---- */
.featured-path {
  padding: 80px 0;
  border-top: 1px solid var(--border);
}

.featured-path-inner {
  display: grid;
  grid-template-columns: 1fr 420px;
  gap: 4rem;
  align-items: start;
}

.label-tag {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid rgba(124,111,255,0.4);
  border-radius: 999px;
  padding: 3px 12px;
  margin-bottom: 1rem;
}

.featured-path-text h2 { margin-bottom: 1rem; }

.featured-path-text p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.75;
  margin-bottom: 1.5rem;
  max-width: 520px;
}

.feature-list {
  list-style: none;
  margin-bottom: 2rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.feature-list li {
  font-size: 0.9rem;
  color: var(--text-muted);
  padding-left: 1.2rem;
  position: relative;
}

.feature-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-size: 0.75rem;
  top: 1px;
}

.meta-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  display: flex;
  gap: 1.5rem;
  margin-bottom: 1rem;
}

.meta-item {
  text-align: center;
  flex: 1;
}

.meta-num {
  display: block;
  font-family: var(--font-serif);
  font-size: 2rem;
  font-weight: 600;
  color: var(--accent);
  line-height: 1;
}

.meta-label {
  display: block;
  font-size: 0.72rem;
  color: var(--text-muted);
  margin-top: 0.3rem;
}

.module-list {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.module-item {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.9rem 1.2rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.875rem;
}

.module-item:last-child { border-bottom: none; }

.module-item.active { background: rgba(124,111,255,0.06); }

.module-num {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 22px;
}

.module-name { flex: 1; color: var(--text-muted); }
.module-item.active .module-name { color: var(--text); font-weight: 500; }

.module-status { font-size: 0.72rem; }
.module-status.available { color: var(--accent); font-weight: 600; }
.module-status.soon { color: var(--text-muted); }

/* ---- PATH HERO ---- */
.path-hero {
  position: relative;
  padding: 130px 2rem 80px;
  overflow: hidden;
}

.path-hero .section-inner { position: relative; z-index: 2; }

.breadcrumb {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 2rem;
}

.breadcrumb a { color: var(--text-muted); transition: color 0.15s; }
.breadcrumb a:hover { color: var(--text); }

.path-hero-badge {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.path-num-large {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.08em;
}

.path-title {
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 600;
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 1.5rem;
}

.path-title em { font-style: italic; color: var(--accent); }

.path-description {
  font-size: 1.05rem;
  color: var(--text-muted);
  line-height: 1.75;
  max-width: 640px;
  margin-bottom: 2rem;
}

.path-meta-row {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.meta-pill {
  font-size: 0.78rem;
  color: var(--text-muted);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px 12px;
}

/* ---- MODULES LIST ---- */
.modules-section { padding: 80px 0; }

.modules-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-bottom: 3rem;
}

.module-card {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 2rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.75rem 2rem;
  transition: border-color 0.2s, transform 0.15s;
  text-decoration: none;
  color: inherit;
}

.module-card.available:hover {
  border-color: var(--accent);
  transform: translateX(4px);
}

.module-card.coming-soon { opacity: 0.6; cursor: default; }

.module-card-left {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
  flex: 1;
}

.module-card-num {
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: 0.08em;
  min-width: 22px;
  padding-top: 4px;
}

.module-card-text h3 {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.module-card-text p {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin-bottom: 0.75rem;
}

.module-topics {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.module-topics span {
  font-size: 0.72rem;
  color: var(--text-muted);
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 2px 10px;
}

.module-card-right {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.75rem;
  min-width: 100px;
}

.module-time {
  font-size: 0.78rem;
  color: var(--text-muted);
}

.status-badge {
  font-size: 0.78rem;
  font-weight: 600;
  border-radius: 999px;
  padding: 4px 12px;
}

.status-badge.available {
  color: var(--accent);
  background: rgba(124,111,255,0.1);
  border: 1px solid rgba(124,111,255,0.3);
}

.status-badge.soon {
  color: var(--text-muted);
  background: rgba(255,255,255,0.04);
  border: 1px solid var(--border);
}

.path-start-cta {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.start-note {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ---- ABOUT CTAS ---- */
.about-ctas {
  display: flex;
  gap: 1rem;
  margin-top: 1.5rem;
  flex-wrap: wrap;
}

/* ---- LESSON PAGE ---- */
.lesson-layout {
  display: grid;
  grid-template-columns: 260px 1fr;
  min-height: 100vh;
  max-width: 1200px;
  margin: 60px auto 0;
  padding: 0 2rem;
  gap: 3rem;
}

.lesson-sidebar {
  padding-top: 3rem;
  position: sticky;
  top: 80px;
  height: fit-content;
  align-self: start;
}

.sidebar-path-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
}

.sidebar-path-label a { color: inherit; }

.sidebar-nav {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin-bottom: 2rem;
}

.sidebar-item {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.6rem 0.75rem;
  border-radius: 8px;
  font-size: 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: background 0.15s, color 0.15s;
}

.sidebar-item:hover { background: var(--bg-hover); color: var(--text); }

.sidebar-item.active {
  background: rgba(124,111,255,0.1);
  color: var(--text);
  font-weight: 500;
}

.sidebar-item.locked { opacity: 0.5; pointer-events: none; }

.sidebar-num {
  font-size: 0.68rem;
  font-weight: 700;
  color: var(--accent);
  min-width: 18px;
}

.sidebar-soon {
  font-size: 0.65rem;
  color: var(--text-muted);
  margin-left: auto;
  background: rgba(255,255,255,0.05);
  border-radius: 4px;
  padding: 1px 6px;
}

.sidebar-brain-link {
  font-size: 0.8rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
}

.sidebar-brain-link a {
  color: var(--accent);
  text-decoration: none;
  transition: opacity 0.15s;
}
.sidebar-brain-link a:hover { opacity: 0.75; }

/* ---- LESSON CONTENT ---- */
.lesson-main { padding: 3rem 0 6rem; }

.lesson-header { margin-bottom: 3rem; }

.lesson-meta-row {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-bottom: 1rem;
}

.lesson-title {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.1;
  margin-bottom: 1.25rem;
}

.lesson-lead {
  font-size: 1.1rem;
  color: var(--text-muted);
  line-height: 1.75;
  max-width: 660px;
}

.lesson-content { max-width: 720px; }

.lesson-section {
  margin-bottom: 4rem;
  padding-bottom: 3rem;
  border-bottom: 1px solid var(--border);
}

.lesson-section:last-child { border-bottom: none; }

.lesson-section h2 {
  font-family: var(--font-serif);
  font-size: 1.7rem;
  font-weight: 600;
  letter-spacing: -0.02em;
  margin-bottom: 1.25rem;
}

.lesson-section h3 {
  font-size: 1rem;
  font-weight: 600;
  margin: 2rem 0 0.75rem;
  color: var(--text);
}

.lesson-section h4 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
}

.lesson-section p {
  font-size: 0.95rem;
  color: var(--text-muted);
  line-height: 1.8;
  margin-bottom: 1rem;
}

.content-list {
  list-style: none;
  margin: 1rem 0 1rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.content-list li {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
  padding-left: 1.5rem;
  position: relative;
}

.content-list li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--accent);
}

.content-list li strong { color: var(--text); }

/* ---- ANATOMY DIAGRAM ---- */
.anatomy-diagram {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 1.5rem 0;
  align-items: center;
}

.anatomy-part {
  background: rgba(124,111,255,0.06);
  border: 1px solid rgba(124,111,255,0.2);
  border-radius: 8px;
  padding: 0.75rem 1rem;
  margin: 0.25rem 0;
}

.anatomy-label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 0.25rem;
}

.anatomy-desc {
  font-size: 0.75rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.anatomy-center { text-align: center; }
.anatomy-right { display: flex; flex-direction: column; }

/* ---- CONCEPT GRID ---- */
.concept-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 1.5rem 0;
}

.concept-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.concept-icon { font-size: 1.5rem; margin-bottom: 0.5rem; }

.concept-card h4 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--text);
}

.concept-card p {
  font-size: 0.83rem;
  color: var(--text-muted);
  line-height: 1.65;
  margin: 0;
}

/* ---- CALLOUTS ---- */
.callout {
  display: flex;
  gap: 1rem;
  border-radius: var(--radius);
  padding: 1.1rem 1.25rem;
  margin: 1.5rem 0;
  font-size: 0.875rem;
  line-height: 1.65;
}

.callout.info { background: rgba(95,191,255,0.06); border: 1px solid rgba(95,191,255,0.2); }
.callout.key { background: rgba(124,111,255,0.07); border: 1px solid rgba(124,111,255,0.25); }
.callout.warn { background: rgba(255,124,110,0.06); border: 1px solid rgba(255,124,110,0.2); }

.callout-icon { font-size: 1rem; flex-shrink: 0; }
.callout-text { color: var(--text-muted); }
.callout-text strong { color: var(--text); }

/* ---- POTENTIAL DISPLAY ---- */
.potential-display {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  margin: 1.5rem 0;
}

.potential-bar {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.potential-resting, .potential-threshold, .potential-peak {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.potential-value {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  font-weight: 600;
  min-width: 80px;
}

.potential-resting .potential-value { color: var(--accent-2); }
.potential-threshold .potential-value { color: #f5a623; }
.potential-peak .potential-value { color: var(--accent-3); }

.potential-label { font-size: 0.85rem; color: var(--text-muted); }

/* ---- AP PHASES ---- */
.ap-phases {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin: 1.5rem 0;
}

.ap-phase {
  display: flex;
  gap: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  align-items: flex-start;
}

.phase-num {
  width: 28px;
  height: 28px;
  min-width: 28px;
  border-radius: 50%;
  background: var(--accent);
  color: white;
  font-size: 0.75rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.phase-content h4 { font-size: 0.875rem; margin-bottom: 0.4rem; }

.phase-content p {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.6;
  margin: 0 0 0.5rem;
}

.phase-time {
  font-size: 0.72rem;
  color: var(--accent);
  font-weight: 600;
}

/* ---- SYNAPSE STEPS ---- */
.synapse-steps {
  display: flex;
  flex-direction: column;
  gap: 0;
  margin: 1.5rem 0;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.synapse-step {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.synapse-step:last-child { border-bottom: none; }

.step-arrow {
  color: var(--accent);
  font-weight: 700;
  flex-shrink: 0;
  padding-top: 1px;
}

.synapse-step strong { color: var(--text); }

/* ---- SUMMARY ---- */
.summary-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 1rem;
}

.summary-item {
  display: flex;
  gap: 1rem;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
}

.summary-icon { font-size: 1.25rem; flex-shrink: 0; }
.summary-item strong { display: block; font-size: 0.875rem; margin-bottom: 0.35rem; }
.summary-item p { font-size: 0.82rem; color: var(--text-muted); margin: 0; line-height: 1.6; }

/* ---- SOURCES ---- */
.sources-section { opacity: 0.85; }

.sources-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.sources-list li {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.65;
  padding-left: 1.25rem;
  position: relative;
}

.sources-list li::before {
  content: "–";
  position: absolute;
  left: 0;
}

.sources-list a { color: var(--accent); }
.sources-list a:hover { text-decoration: underline; }

/* ---- LESSON NAV ---- */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 2rem 0;
  border-top: 1px solid var(--border);
  margin-top: 3rem;
  max-width: 720px;
}

.nav-arrow {
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.nav-arrow:hover { color: var(--text); }

.next-coming {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 0.25rem;
}

.next-label {
  font-size: 0.72rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.next-title {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-muted);
}

.coming-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  background: rgba(255,255,255,0.05);
  border-radius: 4px;
  padding: 1px 6px;
  margin-left: 0.5rem;
}

/* ---- RESPONSIVE ---- */
@media (max-width: 900px) {
  .featured-path-inner {
    grid-template-columns: 1fr;
    gap: 2rem;
  }

  .lesson-layout {
    grid-template-columns: 1fr;
    padding: 0 1.25rem;
  }

  .lesson-sidebar {
    position: static;
    padding-top: 1.5rem;
    border-bottom: 1px solid var(--border);
    padding-bottom: 1.5rem;
  }

  .concept-grid,
  .ap-phases,
  .summary-grid {
    grid-template-columns: 1fr;
  }

  .anatomy-diagram {
    grid-template-columns: 1fr;
  }

  .anatomy-right {
    flex-direction: column;
  }

  .module-card {
    flex-direction: column;
    gap: 1rem;
  }

  .module-card-right {
    flex-direction: row;
    align-items: center;
  }
}

@media (max-width: 768px) {
  .about-inner {
    grid-template-columns: 1fr;
  }

  .about-stats {
    flex-direction: row;
    text-align: left;
    gap: 2rem;
  }

  .footer-inner {
    flex-direction: column;
    gap: 1rem;
    text-align: center;
  }

  .nav-links { gap: 1rem; }

  .path-grid {
    grid-template-columns: 1fr;
  }

  .meta-card {
    gap: 1rem;
  }

  .path-hero {
    padding: 110px 1.25rem 60px;
  }

  .lesson-content { max-width: 100%; }

  .ap-phases { grid-template-columns: 1fr; }

  .path-start-cta {
    flex-direction: column;
    gap: 1rem;
    align-items: flex-start;
  }
}