/* =============================================
   GHAS & GitHub Copilot Hackathon — CIPHER Theme
   A cyberpunk-terminal aesthetic: deep darks,
   neon accents, grid overlays, glowing edges.
   
   Fonts: Chakra Petch (headings) · Lexend (body) · JetBrains Mono (code)
   ============================================= */

/* ----- 1. Custom Properties ----- */
:root {
  --bg-deep: #050810;
  --bg-primary: #0a0f1a;
  --bg-surface: #111827;
  --bg-card: #172033;
  --bg-elevated: #1e293b;
  --bg-highlight: #253349;

  --text-primary: #e2e8f0;
  --text-secondary: #94a3b8;
  --text-tertiary: #64748b;
  --text-heading: #f1f5f9;

  --accent-green: #00ff41;
  --accent-cyan: #00d4ff;
  --accent-pink: #ff0080;
  --accent-amber: #fbbf24;
  --accent-green-dim: rgba(0, 255, 65, 0.15);
  --accent-cyan-dim: rgba(0, 212, 255, 0.12);
  --accent-pink-dim: rgba(255, 0, 128, 0.12);
  --accent-amber-dim: rgba(251, 191, 36, 0.12);

  --track-security: var(--accent-green);
  --track-frontend: var(--accent-cyan);
  --track-backend: var(--accent-pink);
  --track-copilot: var(--accent-amber);

  --border-subtle: rgba(148, 163, 184, 0.08);
  --border-accent: rgba(0, 255, 65, 0.18);

  --font-heading: 'Chakra Petch', sans-serif;
  --font-body: 'Lexend', sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;

  --shadow-glow-green: 0 0 20px rgba(0, 255, 65, 0.08);
  --shadow-glow-cyan: 0 0 20px rgba(0, 212, 255, 0.08);

  --nav-height: 64px;
  --sidebar-width: 280px;
  --max-width: 1200px;

  --transition-fast: 0.15s ease;
  --transition-base: 0.25s ease;
  --transition-slow: 0.4s ease;
}

/* ----- 2. Reset & Base ----- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 24px);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-body);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text-primary);
  background-color: var(--bg-primary);
  background-image:
    linear-gradient(rgba(0, 255, 65, 0.025) 1px, transparent 1px),
    linear-gradient(90deg, rgba(0, 255, 65, 0.025) 1px, transparent 1px);
  background-size: 48px 48px;
  min-height: 100vh;
  overflow-x: hidden;
}

/* Scroll progress bar */
#scroll-progress {
  position: fixed;
  top: 0;
  left: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--accent-green), var(--accent-cyan));
  z-index: 10000;
  transition: width 0.1s linear;
}

::selection {
  background: rgba(0, 255, 65, 0.25);
  color: #fff;
}

/* Custom scrollbar */
::-webkit-scrollbar { width: 8px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb {
  background: var(--bg-elevated);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover { background: var(--bg-highlight); }

img { max-width: 100%; height: auto; display: block; }
a { color: var(--accent-cyan); text-decoration: none; transition: color var(--transition-fast); }
a:hover { color: var(--accent-green); }

/* ----- 3. Typography ----- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  color: var(--text-heading);
  line-height: 1.25;
  letter-spacing: 0.01em;
}
h1 { font-size: clamp(2rem, 5vw, 3rem); margin-bottom: 1rem; }
h2 { font-size: clamp(1.5rem, 3vw, 2rem); margin-top: 2.5rem; margin-bottom: 1rem; }
h3 { font-size: clamp(1.2rem, 2vw, 1.5rem); margin-top: 2rem; margin-bottom: 0.75rem; }
h4 { font-size: 1.1rem; margin-top: 1.5rem; margin-bottom: 0.5rem; }

p { margin-bottom: 1rem; color: var(--text-secondary); }
strong { color: var(--text-primary); font-weight: 600; }
em { font-style: italic; }

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  padding: 2px 7px;
  border-radius: var(--radius-sm);
  color: var(--accent-green);
}

pre {
  background: var(--bg-deep);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
  overflow-x: auto;
  margin: 1.5rem 0;
  position: relative;
}

pre code {
  background: transparent;
  border: none;
  padding: 0;
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--text-primary);
}

/* ----- 4. Layout ----- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.page-header {
  padding: 4rem 0 2rem;
  text-align: center;
}

.page-header h1 {
  background: linear-gradient(135deg, var(--accent-green), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.page-header p {
  max-width: 680px;
  margin: 0 auto;
  font-size: 1.1rem;
}

.section {
  padding: 4rem 0;
}

.section-title {
  text-align: center;
  margin-bottom: 3rem;
}

.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1.5rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1.5rem; }
.grid-4 { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1.5rem; }

/* ----- 5. Navigation ----- */
.site-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(5, 8, 16, 0.85);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  z-index: 1000;
  transition: background var(--transition-base);
}

.site-nav.scrolled {
  background: rgba(5, 8, 16, 0.95);
  border-bottom-color: var(--border-accent);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text-heading);
  text-decoration: none;
  white-space: nowrap;
}

.nav-logo .logo-icon {
  width: 28px;
  height: 28px;
  border: 2px solid var(--accent-green);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  color: var(--accent-green);
  font-family: var(--font-mono);
  font-weight: 700;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0.25rem;
  list-style: none;
}

.nav-links a {
  display: block;
  padding: 0.5rem 0.875rem;
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--accent-green);
  background: var(--accent-green-dim);
}

/* Dropdown */
.nav-dropdown {
  position: relative;
}

.nav-dropdown-trigger {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-dropdown-trigger::after {
  content: '▾';
  font-size: 0.7em;
  transition: transform var(--transition-fast);
}

.nav-dropdown:hover .nav-dropdown-trigger::after {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--bg-card);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-md);
  padding: 0.5rem;
  min-width: 220px;
  opacity: 0;
  visibility: hidden;
  transform: translateX(-50%) translateY(8px);
  transition: all var(--transition-fast);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.5), var(--shadow-glow-green);
}

.nav-dropdown:hover .nav-dropdown-menu {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.nav-dropdown-menu a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
}

.nav-dropdown-menu a .track-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

/* Hamburger */
.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: all var(--transition-fast);
}

.nav-hamburger.open span:nth-child(1) { transform: rotate(45deg) translate(5px, 5px); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; }
.nav-hamburger.open span:nth-child(3) { transform: rotate(-45deg) translate(5px, -5px); }

/* ----- 6. Hero ----- */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 6rem 1.5rem 4rem;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 25% 40%, rgba(0, 255, 65, 0.07) 0%, transparent 55%),
    radial-gradient(ellipse at 75% 30%, rgba(0, 212, 255, 0.05) 0%, transparent 50%),
    radial-gradient(ellipse at 50% 80%, rgba(255, 0, 128, 0.03) 0%, transparent 45%);
  pointer-events: none;
}

/* Scanline overlay */
.hero::after {
  content: '';
  position: absolute;
  inset: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0, 255, 65, 0.015) 2px,
    rgba(0, 255, 65, 0.015) 4px
  );
  pointer-events: none;
  animation: scanline-scroll 8s linear infinite;
}

@keyframes scanline-scroll {
  0% { background-position: 0 0; }
  100% { background-position: 0 100px; }
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.4rem 1rem;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--accent-green);
  background: var(--accent-green-dim);
  border: 1px solid rgba(0, 255, 65, 0.25);
  border-radius: 100px;
  margin-bottom: 1.5rem;
  animation: fadeInDown 0.6s ease both;
}

.hero-badge::before {
  content: '';
  width: 6px;
  height: 6px;
  background: var(--accent-green);
  border-radius: 50%;
  animation: pulse-dot 2s ease infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; box-shadow: 0 0 0 0 rgba(0, 255, 65, 0.4); }
  50% { opacity: 0.7; box-shadow: 0 0 0 6px rgba(0, 255, 65, 0); }
}

.hero h1 {
  font-size: clamp(2.5rem, 7vw, 4.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
  animation: fadeInDown 0.6s ease 0.1s both;
}

.hero h1 .gradient-text {
  background: linear-gradient(135deg, var(--accent-green) 0%, var(--accent-cyan) 50%, var(--accent-pink) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero .subtitle {
  font-family: var(--font-mono);
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--accent-green);
  margin-bottom: 1.5rem;
  animation: fadeInDown 0.6s ease 0.2s both;
}

.hero .subtitle .cursor {
  display: inline-block;
  width: 2px;
  height: 1.2em;
  background: var(--accent-green);
  margin-left: 2px;
  vertical-align: text-bottom;
  animation: blink 1s step-end infinite;
}

@keyframes blink {
  0%, 100% { opacity: 1; }
  50% { opacity: 0; }
}

.hero .hero-desc {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
  animation: fadeInDown 0.6s ease 0.3s both;
}

.hero-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  animation: fadeInDown 0.6s ease 0.4s both;
}

@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-16px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ----- 7. Buttons ----- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.7rem 1.5rem;
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-base);
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent-green);
  color: var(--bg-deep);
  border-color: var(--accent-green);
  box-shadow: 0 0 20px rgba(0, 255, 65, 0.2);
}

.btn-primary:hover {
  background: #33ff66;
  color: var(--bg-deep);
  box-shadow: 0 0 30px rgba(0, 255, 65, 0.35);
  transform: translateY(-1px);
}

.btn-secondary {
  background: transparent;
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
}

.btn-secondary:hover {
  background: var(--accent-cyan-dim);
  color: var(--accent-cyan);
  box-shadow: 0 0 20px rgba(0, 212, 255, 0.15);
  transform: translateY(-1px);
}

/* ----- 8. Cards ----- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1.75rem;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-green), transparent);
  opacity: 0;
  transition: opacity var(--transition-base);
}

.card:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow-green);
  transform: translateY(-2px);
}

.card:hover::before { opacity: 1; }

.card h3 { font-size: 1.15rem; margin-bottom: 0.75rem; margin-top: 0; }
.card p { font-size: 0.92rem; margin-bottom: 0; }

.card-link {
  display: block;
  color: inherit;
  text-decoration: none;
}

.card-link:hover { color: inherit; }

/* Track-colored cards */
.card[data-track="security"] { border-left: 3px solid var(--track-security); }
.card[data-track="security"]::before { background: linear-gradient(90deg, transparent, var(--track-security), transparent); }
.card[data-track="frontend"] { border-left: 3px solid var(--track-frontend); }
.card[data-track="frontend"]::before { background: linear-gradient(90deg, transparent, var(--track-frontend), transparent); }
.card[data-track="backend"] { border-left: 3px solid var(--track-backend); }
.card[data-track="backend"]::before { background: linear-gradient(90deg, transparent, var(--track-backend), transparent); }
.card[data-track="copilot"] { border-left: 3px solid var(--track-copilot); }
.card[data-track="copilot"]::before { background: linear-gradient(90deg, transparent, var(--track-copilot), transparent); }

/* Feature cards on landing */
.feature-card {
  text-align: center;
  padding: 2rem 1.5rem;
}

.feature-card .feature-icon {
  width: 56px;
  height: 56px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin: 0 auto 1rem;
  background: var(--accent-green-dim);
  border: 1px solid rgba(0, 255, 65, 0.2);
}

/* Track header cards */
.track-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  margin-bottom: 1.5rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-subtle);
}

.track-header .track-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  flex-shrink: 0;
}

.track-header h2 {
  margin: 0;
  font-size: 1.5rem;
}

/* ----- 9. Challenge Layout ----- */
.challenge-layout {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  gap: 2rem;
  padding-top: calc(var(--nav-height) + 2rem);
  padding-bottom: 4rem;
  min-height: 100vh;
}

.challenge-sidebar {
  position: sticky;
  top: calc(var(--nav-height) + 2rem);
  align-self: start;
  max-height: calc(100vh - var(--nav-height) - 4rem);
  overflow-y: auto;
  padding-right: 1rem;
}

.sidebar-title {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
  margin-bottom: 0.75rem;
  padding: 0 0.75rem;
}

.sidebar-nav {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.sidebar-nav a {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.75rem;
  font-size: 0.88rem;
  color: var(--text-secondary);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  border-left: 2px solid transparent;
}

.sidebar-nav a:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
}

.sidebar-nav a.active {
  background: var(--accent-green-dim);
  color: var(--accent-green);
  border-left-color: var(--accent-green);
  font-weight: 500;
}

.sidebar-nav[data-track="frontend"] a.active {
  background: var(--accent-cyan-dim);
  color: var(--accent-cyan);
  border-left-color: var(--accent-cyan);
}

.sidebar-nav[data-track="backend"] a.active {
  background: var(--accent-pink-dim);
  color: var(--accent-pink);
  border-left-color: var(--accent-pink);
}

.sidebar-nav[data-track="copilot"] a.active {
  background: var(--accent-amber-dim);
  color: var(--accent-amber);
  border-left-color: var(--accent-amber);
}

.sidebar-nav .challenge-id {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  opacity: 0.7;
  min-width: 2.5rem;
}

.sidebar-nav .challenge-title {
  flex: 1;
  line-height: 1.3;
}

/* Challenge content area */
.challenge-content {
  max-width: 780px;
}

.challenge-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

/* ----- 10. Breadcrumbs ----- */
.breadcrumbs {
  padding: calc(var(--nav-height) + 1.5rem) 0 0;
  font-size: 0.85rem;
  color: var(--text-tertiary);
}

.breadcrumbs a {
  color: var(--text-tertiary);
}

.breadcrumbs a:hover {
  color: var(--accent-green);
}

.breadcrumbs .sep {
  margin: 0 0.5rem;
  opacity: 0.4;
}

.breadcrumbs .current {
  color: var(--text-secondary);
}

/* When used outside challenge layout */
.page-breadcrumbs {
  padding-top: calc(var(--nav-height) + 1.5rem);
}

/* ----- 11. Badges ----- */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.25rem 0.65rem;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 500;
  border-radius: 100px;
  border: 1px solid;
  white-space: nowrap;
}

.badge-security { color: var(--track-security); background: var(--accent-green-dim); border-color: rgba(0, 255, 65, 0.25); }
.badge-frontend { color: var(--track-frontend); background: var(--accent-cyan-dim); border-color: rgba(0, 212, 255, 0.25); }
.badge-backend { color: var(--track-backend); background: var(--accent-pink-dim); border-color: rgba(255, 0, 128, 0.25); }
.badge-copilot { color: var(--track-copilot); background: var(--accent-amber-dim); border-color: rgba(251, 191, 36, 0.25); }
.badge-time { color: var(--text-secondary); background: var(--bg-elevated); border-color: var(--border-subtle); }

/* ----- 12. Tables ----- */
table {
  width: 100%;
  border-collapse: collapse;
  margin: 1.5rem 0;
  font-size: 0.92rem;
}

thead th {
  font-family: var(--font-heading);
  font-weight: 600;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-tertiary);
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 2px solid var(--border-accent);
  background: var(--bg-card);
}

tbody td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  vertical-align: top;
}

tbody tr:hover {
  background: rgba(0, 255, 65, 0.02);
}

tbody tr:last-child td {
  border-bottom: none;
}

/* ----- 13. Lists ----- */
ul, ol {
  margin: 1rem 0;
  padding-left: 1.5rem;
}

li {
  margin-bottom: 0.5rem;
  color: var(--text-secondary);
}

li::marker {
  color: var(--accent-green);
}

/* Checklist style */
.checklist {
  list-style: none;
  padding-left: 0;
}

.checklist li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}

.checklist li:hover {
  background: var(--bg-card);
}

.checklist li::before {
  content: '';
  width: 18px;
  height: 18px;
  border: 2px solid var(--text-tertiary);
  border-radius: 4px;
  flex-shrink: 0;
  margin-top: 3px;
}

/* Resource links */
.resource-list {
  list-style: none;
  padding-left: 0;
}

.resource-list li {
  margin-bottom: 0.25rem;
}

.resource-list a {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 0;
  font-size: 0.92rem;
}

.resource-list a::before {
  content: '→';
  color: var(--accent-green);
  font-family: var(--font-mono);
  font-size: 0.8rem;
}

/* ----- 14. Blockquotes / Notes ----- */
blockquote, .note {
  border-left: 3px solid var(--accent-cyan);
  background: var(--accent-cyan-dim);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
}

blockquote p, .note p {
  margin: 0;
  color: var(--text-primary);
  font-size: 0.92rem;
}

.note-warning {
  border-left-color: var(--accent-amber);
  background: var(--accent-amber-dim);
}

.note-important {
  border-left-color: var(--accent-pink);
  background: var(--accent-pink-dim);
}

/* ----- 15. Prev / Next Navigation ----- */
.prev-next {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  margin-top: 3rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-subtle);
}

.prev-next a {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  padding: 1rem 1.25rem;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: all var(--transition-base);
  text-decoration: none;
}

.prev-next a:hover {
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow-green);
}

.prev-next .label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.prev-next .title {
  font-family: var(--font-heading);
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
}

.prev-next .next {
  text-align: right;
}

.prev-next .placeholder {
  visibility: hidden;
}

/* ----- 16. Footer ----- */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 0;
  margin-top: 4rem;
  text-align: center;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 1.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
  list-style: none;
}

.footer-links a {
  font-size: 0.88rem;
  color: var(--text-tertiary);
}

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

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  font-family: var(--font-mono);
}

/* ----- 17. Content-specific Styles ----- */

/* Security features page */
.feature-section {
  margin-bottom: 3rem;
  padding-bottom: 2rem;
  border-bottom: 1px solid var(--border-subtle);
}

.feature-section:last-of-type {
  border-bottom: none;
}

.feature-section h2 {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.feature-section h2 .section-number {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent-green);
  background: var(--accent-green-dim);
  width: 32px;
  height: 32px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  flex-shrink: 0;
}

.where-to-find {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
  margin: 1rem 0;
}

.where-to-find p {
  margin: 0 0 0.25rem;
  font-size: 0.9rem;
}

.where-to-find ul {
  margin: 0.5rem 0 0;
}

/* Learning objectives page */
.learning-section {
  margin-bottom: 2.5rem;
}

.learning-section h2 {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding-bottom: 0.75rem;
  border-bottom: 2px solid var(--border-accent);
}

.learning-section ul {
  list-style: none;
  padding: 0;
}

.learning-section li {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.6rem 0;
  border-bottom: 1px solid var(--border-subtle);
}

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

.learning-section li::before {
  content: '✓';
  color: var(--accent-green);
  font-family: var(--font-mono);
  font-weight: 700;
  flex-shrink: 0;
  margin-top: 1px;
}

/* ----- 18. Track Sections on Challenges Page ----- */
.track-section {
  margin-bottom: 3rem;
}

.track-section .challenge-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 1rem;
}

.challenge-card {
  padding: 1.25rem 1.5rem;
}

.challenge-card .card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 0.75rem;
}

.challenge-card .challenge-label {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 600;
  opacity: 0.7;
}

.challenge-card h3 {
  font-size: 1.05rem;
  margin: 0 0 0.5rem;
}

.challenge-card p {
  font-size: 0.88rem;
  margin: 0;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ----- 19. Animations & Effects ----- */
.fade-in {
  animation: fadeInUp 0.5s ease both;
}

.fade-in-delay-1 { animation-delay: 0.1s; }
.fade-in-delay-2 { animation-delay: 0.2s; }
.fade-in-delay-3 { animation-delay: 0.3s; }
.fade-in-delay-4 { animation-delay: 0.4s; }

/* Glow pulse on certain elements */
@keyframes glow-pulse {
  0%, 100% { box-shadow: 0 0 15px rgba(0, 255, 65, 0.08); }
  50% { box-shadow: 0 0 25px rgba(0, 255, 65, 0.15); }
}

.glow-pulse { animation: glow-pulse 3s ease infinite; }

/* Gradient text utility */
.text-gradient {
  background: linear-gradient(135deg, var(--accent-green), var(--accent-cyan));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ----- 20. Responsive ----- */
@media (max-width: 1024px) {
  .challenge-layout {
    grid-template-columns: 1fr;
  }

  .challenge-sidebar {
    position: static;
    max-height: none;
    padding-right: 0;
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border-subtle);
  }

  .sidebar-nav {
    flex-direction: row;
    flex-wrap: wrap;
    gap: 0.5rem;
  }

  .sidebar-nav a {
    padding: 0.4rem 0.75rem;
    font-size: 0.82rem;
    border-left: none;
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-sm);
  }

  .sidebar-nav a.active {
    border-left-width: 1px;
  }
}

@media (max-width: 768px) {
  :root {
    --nav-height: 56px;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg-card);
    border-bottom: 1px solid var(--border-accent);
    padding: 1rem;
    gap: 0.25rem;
    box-shadow: 0 16px 32px rgba(0, 0, 0, 0.5);
  }

  .nav-links.open {
    display: flex;
  }

  .nav-hamburger {
    display: flex;
  }

  .nav-dropdown-menu {
    position: static;
    transform: none;
    opacity: 1;
    visibility: visible;
    box-shadow: none;
    border: none;
    background: var(--bg-elevated);
    padding: 0.5rem;
    margin-top: 0.25rem;
    border-radius: var(--radius-sm);
  }

  .nav-dropdown:hover .nav-dropdown-menu {
    transform: none;
  }

  .hero {
    min-height: 85vh;
    padding: 5rem 1rem 3rem;
  }

  .hero h1 {
    font-size: clamp(1.8rem, 8vw, 2.8rem);
  }

  .hero-buttons {
    flex-direction: column;
    align-items: center;
  }

  .prev-next {
    grid-template-columns: 1fr;
  }

  .grid-2, .grid-3, .grid-4 {
    grid-template-columns: 1fr;
  }

  .track-section .challenge-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  body { font-size: 15px; }

  .container { padding: 0 1rem; }

  .page-header { padding: 3rem 0 1.5rem; }

  .card { padding: 1.25rem; }

  table { font-size: 0.82rem; }

  thead th, tbody td { padding: 0.5rem 0.6rem; }
}

/* ----- 21. Prism.js Overrides ----- */
pre[class*="language-"],
code[class*="language-"] {
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

pre[class*="language-"] {
  background: var(--bg-deep);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-md);
  padding: 1.25rem 1.5rem;
}

/* ----- 22. Page-specific main padding ----- */
.page-main {
  padding-top: calc(var(--nav-height) + 2rem);
  padding-bottom: 4rem;
  min-height: 80vh;
}

/* Tech stack section on landing */
.tech-stack {
  max-width: 600px;
  margin: 0 auto;
}

/* Ground rules / info boxes */
.info-box {
  background: var(--bg-card);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-md);
  padding: 1.5rem 1.75rem;
  margin: 1.5rem 0;
}

.info-box h3 {
  margin-top: 0;
  color: var(--accent-green);
}

/* Challenge description special styling */
.challenge-body h2 {
  margin-top: 2.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border-subtle);
}

.challenge-body h2:first-child {
  margin-top: 1rem;
}

/* Power move callout */
.power-move {
  border-left: 3px solid var(--accent-amber);
  background: var(--accent-amber-dim);
  padding: 1rem 1.25rem;
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  margin: 1.5rem 0;
}

.power-move strong {
  color: var(--accent-amber);
}

.power-move p {
  margin: 0;
  color: var(--text-primary);
  font-size: 0.92rem;
}

/* ----- 23. Lucide Icon Styles ----- */

/* Feature icons on the homepage */
.feature-icon svg {
  width: 32px;
  height: 32px;
  stroke: var(--accent-green);
  stroke-width: 1.5;
  transition: all var(--transition-base);
  filter: drop-shadow(0 0 6px rgba(0, 255, 65, 0.3));
}

.feature-card:hover .feature-icon svg {
  stroke: #33ff66;
  filter: drop-shadow(0 0 12px rgba(0, 255, 65, 0.5));
  transform: scale(1.1);
}

/* Track icons on challenges page */
.track-icon svg {
  width: 24px;
  height: 24px;
  stroke-width: 1.75;
}

/* Badge time icon */
.badge-time svg {
  width: 12px;
  height: 12px;
  stroke: currentColor;
  stroke-width: 2;
  vertical-align: -1px;
  flex-shrink: 0;
}

/* Icons inside h3 headings (resource cards, track cards) */
.card h3 svg,
h3 svg {
  width: 20px;
  height: 20px;
  stroke-width: 1.75;
  vertical-align: -3px;
  display: inline;
  flex-shrink: 0;
}

/* Track card heading icons — inherit card accent color */
[data-track="security"] h3 svg { stroke: var(--track-security); filter: drop-shadow(0 0 4px rgba(0, 255, 65, 0.25)); }
[data-track="frontend"] h3 svg { stroke: var(--track-frontend); filter: drop-shadow(0 0 4px rgba(0, 212, 255, 0.25)); }
[data-track="backend"] h3 svg  { stroke: var(--track-backend); filter: drop-shadow(0 0 4px rgba(255, 0, 128, 0.25)); }
[data-track="copilot"] h3 svg  { stroke: var(--track-copilot); filter: drop-shadow(0 0 4px rgba(251, 191, 36, 0.25)); }

/* Resource card icons on homepage */
.card-link h3 svg {
  margin-right: 2px;
}

/* Learning objectives section icons */
.learning-section h2 svg {
  width: 24px;
  height: 24px;
  stroke-width: 1.75;
  vertical-align: -4px;
  flex-shrink: 0;
}

/* Checkmark icon in security-features page */
.feature-section li svg {
  width: 14px;
  height: 14px;
  stroke: var(--accent-green);
  stroke-width: 2;
  vertical-align: -2px;
  display: inline;
}

/* Lucide icon hover glow animation for cards */
@keyframes icon-glow-pulse {
  0%, 100% { filter: drop-shadow(0 0 6px rgba(0, 255, 65, 0.3)); }
  50% { filter: drop-shadow(0 0 14px rgba(0, 255, 65, 0.55)); }
}

.feature-icon:hover svg {
  animation: icon-glow-pulse 1.5s ease infinite;
}