/* ===========================
   ROOT VARIABLES  (identical to chapter CSS)
=========================== */
:root {
  --bg-deep:    #0a0f1e;
  --bg-main:    #0f172a;
  --bg-card:    #1e293b;
  --bg-card2:   #162032;
  --bg-hover:   #243447;
  --accent:     #38bdf8;
  --accent2:    #818cf8;
  --success:    #22c55e;
  --warning:    #f59e0b;
  --danger:     #f43f5e;
  --text-main:  #e2e8f0;
  --text-muted: #94a3b8;
  --text-dim:   #64748b;
  --border:     rgba(56,189,248,0.15);
  --glow:       rgba(56,189,248,0.25);
  --radius:     16px;
  --radius-sm:  10px;
}

/* ===========================
   BASE
=========================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Space Grotesk', sans-serif;
  background: var(--bg-main);
  color: var(--text-main);
  line-height: 1.75;
  overflow-x: hidden;
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-deep); }
::-webkit-scrollbar-thumb { background: var(--accent); border-radius: 3px; }

/* ===========================
   BACKGROUND GRID + GLOW
=========================== */
body::before {
  content: '';
  position: fixed; inset: 0; z-index: 0;
  background-image:
    linear-gradient(rgba(56,189,248,0.04) 1px, transparent 1px),
    linear-gradient(90deg, rgba(56,189,248,0.04) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
}
.bg-orb {
  position: fixed; border-radius: 50%;
  filter: blur(120px); opacity: 0.18; pointer-events: none; z-index: 0;
}
.bg-orb-1 { width: 600px; height: 600px; background: #38bdf8; top: -200px; left: -200px; }
.bg-orb-2 { width: 500px; height: 500px; background: #818cf8; bottom: -200px; right: -200px; }
.bg-orb-3 { width: 300px; height: 300px; background: #22c55e; top: 50%; left: 50%; transform: translate(-50%,-50%); }

/* ===========================
   NAVBAR
=========================== */
.course-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  background: rgba(10,15,30,0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
}
.course-nav .brand {
  font-family: 'Syne', sans-serif;
  font-weight: 800; font-size: 1.1rem;
  color: var(--accent);
  text-decoration: none;
  display: flex; align-items: center; gap: 10px;
}
.course-nav .brand .brand-icon {
  width: 34px; height: 34px; background: linear-gradient(135deg,#38bdf8,#818cf8);
  border-radius: 8px; display: flex; align-items: center; justify-content: center;
  font-size: 1rem; color: #fff;
}
.nav-link-item {
  color: var(--text-muted); font-size: 0.88rem; font-weight: 500;
  text-decoration: none; padding: 6px 10px; border-radius: 8px;
  transition: all 0.2s;
}
.nav-link-item:hover { color: var(--accent); background: rgba(56,189,248,0.08); }
.nav-start-btn {
  background: linear-gradient(135deg,#38bdf8,#818cf8);
  color: #fff; font-size: 0.82rem; font-weight: 700;
  padding: 8px 20px; border-radius: 30px; text-decoration: none;
  transition: all 0.25s; letter-spacing: 0.5px; border: none;
  display: inline-flex; align-items: center; gap: 6px;
}
.nav-start-btn:hover { transform: translateY(-2px); box-shadow: 0 8px 24px rgba(56,189,248,0.35); color: #fff; }
.nav-hamburger {
  background: none; border: 1px solid var(--border);
  color: var(--text-muted); width: 36px; height: 36px;
  border-radius: 8px; display: none; align-items: center; justify-content: center;
  cursor: pointer; font-size: 1rem;
}

/* ===========================
   HERO
=========================== */
.hero-section {
  min-height: 100vh;
  display: flex; align-items: center;
  padding: 130px 0 80px;
  position: relative; overflow: hidden;
}
.chapter-number-pill {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(56,189,248,0.1); border: 1px solid rgba(56,189,248,0.3);
  color: var(--accent); font-weight: 700; letter-spacing: 2px;
  font-size: 0.75rem; text-transform: uppercase;
  padding: 6px 18px; border-radius: 30px; margin-bottom: 24px;
}
.hero-title {
  font-family: 'Syne', sans-serif;
  font-size: clamp(2.6rem, 6vw, 5rem);
  font-weight: 800; line-height: 1.1;
  margin-bottom: 24px;
}
.hero-title .gradient-text {
  background: linear-gradient(135deg, #38bdf8 0%, #818cf8 50%, #22c55e 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-desc {
  font-size: 1.1rem; color: var(--text-muted);
  max-width: 560px; margin-bottom: 36px;
}
.hero-stats {
  display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 36px;
}
.hero-stat-pill {
  display: flex; align-items: center; gap: 8px;
  background: var(--bg-card); border: 1px solid var(--border);
  padding: 10px 18px; border-radius: 30px; font-size: 0.83rem; font-weight: 600;
  transition: all 0.3s;
}
.hero-stat-pill:hover { border-color: var(--accent); transform: translateY(-3px); }
.hero-stat-pill .stat-icon { font-size: 1rem; }
.hero-stat-val { font-weight: 800; color: var(--text-main); }
.hero-stat-lbl { color: var(--text-muted); font-size: 0.78rem; }

.hero-cta-group { display: flex; flex-wrap: wrap; gap: 14px; }
.btn-primary-hero {
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  color: #fff; font-weight: 700; padding: 14px 28px;
  border-radius: 12px; text-decoration: none;
  display: inline-flex; align-items: center; gap: 10px;
  font-size: 0.95rem; transition: all 0.3s; border: none;
  box-shadow: 0 8px 24px rgba(56,189,248,0.3);
}
.btn-primary-hero:hover { transform: translateY(-4px); box-shadow: 0 14px 36px rgba(56,189,248,0.45); color: #fff; }
.btn-outline-hero {
  background: transparent; border: 1px solid var(--border);
  color: var(--text-main); font-weight: 600; padding: 13px 24px;
  border-radius: 12px; text-decoration: none;
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.93rem; transition: all 0.3s;
}
.btn-outline-hero:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-3px); background: rgba(56,189,248,0.06); }

/* Hero code window */
.hero-visual { position: relative; }
.hero-code-window {
  background: #0d1b2a;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 40px 80px rgba(0,0,0,0.5), 0 0 60px rgba(56,189,248,0.1);
}
.window-bar {
  background: #1a2535; padding: 12px 16px;
  display: flex; align-items: center; gap: 8px;
  border-bottom: 1px solid var(--border);
}
.dot { width: 12px; height: 12px; border-radius: 50%; }
.dot-r { background: #f43f5e; }
.dot-y { background: #f59e0b; }
.dot-g { background: #22c55e; }
.window-title { margin-left: 8px; font-size: 0.75rem; color: var(--text-dim); font-family: 'Fira Code', monospace; }
.window-body { padding: 24px; font-family: 'Fira Code', monospace; font-size: 0.85rem; }
.code-line { display: flex; margin-bottom: 8px; }
.ln { color: #2d4a6b; margin-right: 20px; user-select: none; min-width: 20px; text-align: right; }
.kw  { color: #c792ea; }
.fn  { color: #82aaff; }
.str { color: #c3e88d; }
.cm  { color: #546e7a; font-style: italic; }
.op  { color: #89ddff; }
.num { color: #f78c6c; }
.ot  { color: #e2e8f0; }

.floating-badge {
  position: absolute;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: 12px; padding: 12px 18px;
  display: flex; align-items: center; gap: 10px;
  font-size: 0.82rem; font-weight: 600;
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
  animation: floatBadge 3s ease-in-out infinite;
}
.floating-badge-1 { top: -20px; right: -20px; animation-delay: 0s; }
.floating-badge-2 { bottom: -20px; left: -20px; animation-delay: 1.5s; }
@keyframes floatBadge {
  0%,100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

/* ===========================
   SECTION HEADERS
=========================== */
.section-label {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.72rem; font-weight: 700; letter-spacing: 2px;
  text-transform: uppercase; color: var(--accent);
  background: rgba(56,189,248,0.1); border: 1px solid rgba(56,189,248,0.2);
  padding: 5px 14px; border-radius: 20px; margin-bottom: 14px;
}
.section-title {
  font-family: 'Syne', sans-serif;
  font-size: clamp(1.8rem, 4vw, 2.8rem);
  font-weight: 800; line-height: 1.2;
  margin-bottom: 16px;
}
.section-sub { color: var(--text-muted); font-size: 1rem; max-width: 600px; }
.section-divider {
  width: 60px; height: 4px;
  background: linear-gradient(90deg, #38bdf8, #818cf8);
  border-radius: 2px; margin: 20px 0;
}

/* ===========================
   CARDS – general
=========================== */
.glass-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px; transition: all 0.35s;
}
.glass-card:hover {
  border-color: rgba(56,189,248,0.4);
  box-shadow: 0 20px 50px rgba(0,0,0,0.3), 0 0 30px rgba(56,189,248,0.07);
  transform: translateY(-5px);
}

/* ===========================
   CALLOUT BOXES
=========================== */
.callout {
  border-radius: var(--radius-sm); padding: 18px 22px;
  display: flex; gap: 14px; align-items: flex-start; margin: 20px 0;
}
.callout-icon { font-size: 1.2rem; margin-top: 2px; min-width: 22px; }
.callout-blue   { background: rgba(56,189,248,0.08); border-left: 4px solid #38bdf8; }
.callout-green  { background: rgba(34,197,94,0.08);  border-left: 4px solid #22c55e; }
.callout-warn   { background: rgba(245,158,11,0.08); border-left: 4px solid #f59e0b; }
.callout-purple { background: rgba(129,140,248,0.08);border-left: 4px solid #818cf8; }
.callout .callout-title { font-weight: 700; font-size: 0.88rem; letter-spacing: 0.5px; }
.callout .callout-body  { font-size: 0.9rem; color: var(--text-muted); margin-top: 4px; }

/* ===========================
   KEYWORD HIGHLIGHT
=========================== */
.kw-highlight {
  background: rgba(56,189,248,0.12); color: var(--accent);
  padding: 1px 8px; border-radius: 5px;
  font-family: 'Fira Code', monospace; font-size: 0.88em; font-weight: 500;
}
.kw-green   { background: rgba(34,197,94,0.12);   color: #22c55e; }
.kw-warn    { background: rgba(245,158,11,0.12);  color: #f59e0b; }
.kw-purple  { background: rgba(129,140,248,0.12); color: #818cf8; }

/* ===========================
   STATISTICS COUNTER CARDS
=========================== */
.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 20px;
}
.stat-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 28px 24px;
  text-align: center; transition: all 0.35s;
  position: relative; overflow: hidden;
}
.stat-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, transparent 60%, rgba(56,189,248,0.04));
  pointer-events: none;
}
.stat-card:hover { border-color: rgba(56,189,248,0.4); transform: translateY(-6px); box-shadow: 0 20px 50px rgba(0,0,0,0.3); }
.stat-card .stat-icon-wrap {
  width: 60px; height: 60px; border-radius: 16px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.5rem; margin: 0 auto 16px;
}
.stat-card .stat-number {
  font-family: 'Syne', sans-serif; font-size: 2.4rem; font-weight: 800;
  line-height: 1; margin-bottom: 6px;
}
.stat-card .stat-label {
  font-size: 0.85rem; color: var(--text-muted); font-weight: 500;
}

/* ===========================
   CONTINUE LEARNING BANNER
=========================== */
.continue-banner {
  background: linear-gradient(135deg, rgba(56,189,248,0.1), rgba(129,140,248,0.1));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 32px 36px; position: relative; overflow: hidden;
}
.continue-banner::before {
  content: '';
  position: absolute; top: -50%; right: -100px;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(56,189,248,0.12), transparent 70%);
  pointer-events: none;
}
.continue-banner::after {
  content: '';
  position: absolute; left: 0; top: 0; bottom: 0;
  width: 5px; background: linear-gradient(180deg, #38bdf8, #818cf8);
  border-radius: 12px 0 0 12px;
}
.continue-badge {
  display: inline-flex; align-items: center; gap: 8px;
  background: rgba(56,189,248,0.1); border: 1px solid var(--border);
  padding: 5px 14px; border-radius: 20px;
  font-size: 0.72rem; font-weight: 700; letter-spacing: 2px; text-transform: uppercase;
  color: var(--accent); margin-bottom: 14px;
}
.btn-continue {
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  color: #fff; font-weight: 700; padding: 12px 26px;
  border-radius: 10px; text-decoration: none;
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.9rem; transition: all 0.3s; border: none;
}
.btn-continue:hover { transform: translateY(-3px); box-shadow: 0 10px 28px rgba(56,189,248,0.35); color: #fff; }

/* ===========================
   INSTRUCTOR SECTION
=========================== */
.instructor-profile-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 32px;
  text-align: center; transition: all 0.35s;
}
.instructor-profile-card:hover {
  border-color: rgba(56,189,248,0.4);
  box-shadow: 0 20px 50px rgba(0,0,0,0.3);
}
.instructor-avatar {
  width: 120px; height: 120px; border-radius: 50%;
  background: linear-gradient(135deg, rgba(56,189,248,0.15), rgba(129,140,248,0.15));
  border: 3px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 20px; overflow: hidden;
  box-shadow: 0 0 40px rgba(56,189,248,0.2);
}
.instructor-name {
  font-family: 'Syne', sans-serif; font-size: 1.5rem; font-weight: 800;
  margin-bottom: 6px;
}
.instructor-role {
  font-size: 0.82rem; color: var(--text-muted); margin-bottom: 20px;
  display: flex; flex-wrap: wrap; justify-content: center; gap: 8px;
}
.role-pill {
  background: rgba(56,189,248,0.1); border: 1px solid rgba(56,189,248,0.2);
  color: var(--accent); padding: 3px 12px; border-radius: 20px;
  font-size: 0.75rem; font-weight: 600;
}
.social-links {
  display: flex; justify-content: center; gap: 12px; margin: 20px 0;
}
.social-link {
  width: 40px; height: 40px; border-radius: 10px;
  background: var(--bg-card2); border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted); font-size: 1rem; text-decoration: none;
  transition: all 0.3s;
}
.social-link:hover { border-color: var(--accent); color: var(--accent); transform: translateY(-3px); }

/* Philosophy quote */
.philosophy-card {
  background: linear-gradient(135deg, rgba(56,189,248,0.06), rgba(129,140,248,0.06));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 24px 28px; position: relative; margin-top: 20px;
}
.philosophy-card::before {
  content: '"'; font-size: 5rem; font-family: 'Syne', sans-serif;
  color: rgba(56,189,248,0.15); position: absolute;
  top: -10px; left: 16px; line-height: 1;
}
.philosophy-text {
  font-family: 'Syne', sans-serif; font-size: 0.95rem;
  font-weight: 600; color: var(--text-main); line-height: 1.7;
  font-style: italic; padding-top: 12px;
}

/* Tech badges */
.tech-badges-wrap { display: flex; flex-wrap: wrap; gap: 10px; }
.tech-badge {
  display: inline-flex; align-items: center; gap: 7px;
  background: var(--bg-card); border: 1px solid var(--border);
  padding: 7px 14px; border-radius: 8px; font-size: 0.8rem; font-weight: 600;
  transition: all 0.25s;
}
.tech-badge:hover { border-color: var(--accent); background: rgba(56,189,248,0.06); transform: translateY(-2px); }
.tech-badge i { font-size: 0.9rem; }

/* Journey timeline */
.journey-list { display: flex; flex-direction: column; gap: 0; position: relative; padding-left: 28px; }
.journey-list::before {
  content: ''; position: absolute; left: 8px; top: 8px; bottom: 8px;
  width: 2px; background: linear-gradient(180deg, #38bdf8, #818cf8, #22c55e);
  border-radius: 2px;
}
.journey-item { position: relative; padding-bottom: 24px; }
.journey-item:last-child { padding-bottom: 0; }
.journey-dot {
  position: absolute; left: -24px; top: 6px;
  width: 14px; height: 14px; border-radius: 50%;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  box-shadow: 0 0 10px rgba(56,189,248,0.4);
}
.journey-content {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 16px 20px;
  transition: all 0.3s;
}
.journey-content:hover { border-color: rgba(56,189,248,0.35); transform: translateX(6px); }
.journey-title { font-weight: 700; font-size: 0.9rem; margin-bottom: 4px; }
.journey-desc { font-size: 0.82rem; color: var(--text-muted); }

/* Instructor stats mini */
.inst-stats-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 14px;
}
.inst-stat-card {
  background: var(--bg-card2); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 20px; text-align: center;
  transition: all 0.3s;
}
.inst-stat-card:hover { border-color: rgba(56,189,248,0.35); transform: translateY(-3px); }
.inst-stat-num {
  font-family: 'Syne', sans-serif; font-size: 1.8rem; font-weight: 800;
}
.inst-stat-lbl { font-size: 0.75rem; color: var(--text-muted); margin-top: 4px; }

/* ===========================
   ABOUT COURSE SECTION
=========================== */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
}
.feature-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 22px;
  transition: all 0.3s; text-align: center;
}
.feature-card:hover {
  border-color: rgba(56,189,248,0.4);
  transform: translateY(-6px);
  box-shadow: 0 20px 40px rgba(0,0,0,0.25);
}
.feature-card .f-icon {
  width: 54px; height: 54px; border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.4rem; margin: 0 auto 16px;
}
.feature-card h6 { font-weight: 700; margin-bottom: 8px; }
.feature-card p  { font-size: 0.83rem; color: var(--text-muted); margin: 0; }

/* Who is it for */
.audience-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 20px 22px;
  display: flex; align-items: flex-start; gap: 14px;
  transition: all 0.3s;
}
.audience-card:hover { border-color: rgba(56,189,248,0.35); transform: translateX(6px); }
.audience-icon {
  width: 42px; height: 42px; min-width: 42px;
  border-radius: 10px; display: flex; align-items: center;
  justify-content: center; font-size: 1rem;
}

/* ===========================
   COURSE ROADMAP
=========================== */
.roadmap-container { position: relative; }
.roadmap-spine {
  position: absolute; left: 50%; top: 0; bottom: 0;
  width: 3px; transform: translateX(-50%);
  background: linear-gradient(180deg, #38bdf8, #818cf8, #22c55e, #f59e0b, #f43f5e);
  border-radius: 2px;
}
.roadmap-phase-header {
  text-align: center; position: relative; margin: 40px 0 24px;
}
.phase-badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 8px 20px; border-radius: 30px; font-weight: 700;
  font-size: 0.8rem; letter-spacing: 1px; text-transform: uppercase;
  position: relative; z-index: 1;
}
.phase-foundation { background: rgba(56,189,248,0.15); color: #38bdf8; border: 1px solid rgba(56,189,248,0.3); }
.phase-project     { background: rgba(34,197,94,0.15);  color: #22c55e;  border: 1px solid rgba(34,197,94,0.3);  }
.phase-intermediate{ background: rgba(129,140,248,0.15);color: #818cf8;  border: 1px solid rgba(129,140,248,0.3);}
.phase-advanced    { background: rgba(245,158,11,0.15); color: #f59e0b;  border: 1px solid rgba(245,158,11,0.3); }
.phase-mega        { background: rgba(244,63,94,0.15);  color: #f43f5e;  border: 1px solid rgba(244,63,94,0.3);  }

.roadmap-item {
  display: flex; gap: 20px; margin-bottom: 16px; align-items: flex-start;
  position: relative;
}
.roadmap-item.left-side  { flex-direction: row-reverse; }
.roadmap-node {
  width: 44px; height: 44px; min-width: 44px; border-radius: 50%;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.78rem; font-weight: 800; z-index: 2; position: relative;
  border: 3px solid;
}
.node-done     { border-color: #22c55e; color: #22c55e; background: rgba(34,197,94,0.12); box-shadow: 0 0 18px rgba(34,197,94,0.3); }
.node-active   { border-color: #38bdf8; color: #38bdf8; background: rgba(56,189,248,0.12); box-shadow: 0 0 18px rgba(56,189,248,0.4); animation: nodePulse 2s infinite; }
.node-pending  { border-color: var(--text-dim); color: var(--text-dim); background: var(--bg-main); }
.node-project  { border-color: #22c55e; color: #22c55e; background: rgba(34,197,94,0.12); }
.node-mega     { border-color: #f43f5e; color: #f43f5e; background: rgba(244,63,94,0.12); }
@keyframes nodePulse { 0%,100%{ box-shadow: 0 0 15px rgba(56,189,248,0.3); } 50%{ box-shadow: 0 0 30px rgba(56,189,248,0.6); } }

.roadmap-card {
  flex: 1; background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 16px 20px; transition: all 0.3s;
}
.roadmap-card:hover { border-color: rgba(56,189,248,0.35); transform: translateY(-3px); box-shadow: 0 10px 28px rgba(0,0,0,0.2); }
.roadmap-card.available-card { border-color: rgba(56,189,248,0.3); }
.roadmap-card.project-card { border-color: rgba(34,197,94,0.3); background: rgba(34,197,94,0.04); }
.roadmap-card.mega-card { border-color: rgba(244,63,94,0.3); background: rgba(244,63,94,0.04); }
.roadmap-ch-num { font-size: 0.7rem; font-weight: 700; letter-spacing: 1px; text-transform: uppercase; color: var(--text-dim); margin-bottom: 4px; font-family: 'Fira Code', monospace; }
.roadmap-ch-title { font-weight: 700; font-size: 0.92rem; margin-bottom: 6px; }
.roadmap-ch-topics { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 8px; }
.topic-tag { font-size: 0.7rem; background: rgba(56,189,248,0.08); color: var(--text-muted); padding: 2px 10px; border-radius: 20px; border: 1px solid rgba(56,189,248,0.1); }
.ch-status-pill {
  display: inline-flex; align-items: center; gap: 5px;
  font-size: 0.68rem; font-weight: 700; padding: 3px 10px; border-radius: 20px;
  margin-left: 8px;
}
.status-available { background: rgba(34,197,94,0.15); color: #22c55e; border: 1px solid rgba(34,197,94,0.3); }
.status-coming    { background: rgba(100,116,139,0.15); color: var(--text-dim); border: 1px solid rgba(100,116,139,0.2); }
.status-done      { background: rgba(56,189,248,0.15); color: var(--accent); border: 1px solid rgba(56,189,248,0.3); }

/* Roadmap connector (simple vertical) */
.roadmap-flow { position: relative; padding-left: 0; }

/* ===========================
   CHAPTER CARDS SECTION
=========================== */
.chapters-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 20px;
}
.chapter-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); overflow: hidden; transition: all 0.35s;
  position: relative;
}
.chapter-card.available:hover {
  border-color: rgba(56,189,248,0.45);
  transform: translateY(-8px);
  box-shadow: 0 24px 50px rgba(0,0,0,0.3), 0 0 30px rgba(56,189,248,0.08);
}
.chapter-card.locked { opacity: 0.65; }
.chapter-card-header {
  padding: 20px 22px; border-bottom: 1px solid var(--border);
  display: flex; align-items: center; justify-content: space-between;
  background: linear-gradient(135deg, rgba(56,189,248,0.06), rgba(129,140,248,0.06));
}
.ch-num-badge {
  font-family: 'Fira Code', monospace; font-size: 0.72rem; font-weight: 800;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; letter-spacing: 2px;
}
.chapter-card-body { padding: 22px; }
.chapter-card-body h5 { font-weight: 700; margin-bottom: 12px; font-size: 1rem; }
.chapter-card-body p { font-size: 0.85rem; color: var(--text-muted); margin-bottom: 16px; }
.chapter-topics-list { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 18px; }
.ch-topic-tag {
  font-size: 0.72rem; background: rgba(56,189,248,0.08);
  color: var(--accent); padding: 3px 10px; border-radius: 20px;
  border: 1px solid rgba(56,189,248,0.15);
}
.btn-open-chapter {
  width: 100%; display: flex; align-items: center; justify-content: center;
  gap: 8px; background: linear-gradient(135deg, #38bdf8, #818cf8);
  color: #fff; font-weight: 700; padding: 12px 20px;
  border-radius: 10px; text-decoration: none; font-size: 0.88rem;
  transition: all 0.3s; border: none;
}
.btn-open-chapter:hover { box-shadow: 0 8px 24px rgba(56,189,248,0.3); color: #fff; }
.btn-locked-chapter {
  width: 100%; display: flex; align-items: center; justify-content: center;
  gap: 8px; background: var(--bg-card2); border: 1px solid var(--border);
  color: var(--text-dim); font-weight: 600; padding: 12px 20px;
  border-radius: 10px; font-size: 0.88rem;
}

/* completed overlay */
.chapter-card .completed-badge {
  position: absolute; top: 14px; right: 14px;
  background: rgba(34,197,94,0.15); border: 1px solid rgba(34,197,94,0.4);
  color: #22c55e; font-size: 0.7rem; font-weight: 700;
  padding: 3px 10px; border-radius: 20px;
  display: none;
}
.chapter-card.completed .completed-badge { display: flex; align-items: center; gap: 4px; }

/* ===========================
   PROGRESS TRACKER
=========================== */
.progress-section {
  background: linear-gradient(135deg, rgba(56,189,248,0.08), rgba(129,140,248,0.08));
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 36px; position: relative; overflow: hidden;
}
.progress-section::before {
  content: ''; position: absolute; top: -50%; right: -100px;
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(56,189,248,0.15), transparent 70%);
  pointer-events: none;
}
.big-progress { height: 12px; background: var(--bg-hover); border-radius: 6px; overflow: hidden; }
.big-progress-bar {
  height: 100%; width: 0%;
  background: linear-gradient(90deg, #38bdf8, #818cf8);
  border-radius: 6px; transition: width 1s ease-out;
  position: relative;
}
.big-progress-bar::after {
  content: ''; position: absolute; right: 0; top: 0; bottom: 0; width: 20px;
  background: rgba(255,255,255,0.3); animation: shimmer 2s infinite;
}
@keyframes shimmer { 0%{opacity:0} 50%{opacity:1} 100%{opacity:0} }
.progress-steps { display: flex; gap: 0; position: relative; margin: 30px 0; overflow: hidden; }
.progress-steps::before {
  content: ''; position: absolute; top: 20px; left: 0; right: 0; height: 3px;
  background: var(--bg-hover); z-index: 0;
}
.progress-step { flex: 1; text-align: center; position: relative; z-index: 1; }
.ps-circle {
  width: 42px; height: 42px; border-radius: 50%; margin: 0 auto 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 0.85rem; font-weight: 700; border: 3px solid;
  position: relative; background: var(--bg-main);
}
.ps-done    { border-color: #22c55e; color: #22c55e; background: rgba(34,197,94,0.1); }
.ps-active  { border-color: #38bdf8; color: #38bdf8; background: rgba(56,189,248,0.1); box-shadow: 0 0 20px rgba(56,189,248,0.4); animation: pulse 2s infinite; }
.ps-pending { border-color: var(--text-dim); color: var(--text-dim); }
@keyframes pulse { 0%,100%{box-shadow:0 0 15px rgba(56,189,248,0.3)} 50%{box-shadow:0 0 30px rgba(56,189,248,0.6)} }
.ps-label { font-size: 0.72rem; color: var(--text-muted); font-weight: 600; }

/* ===========================
   OBJ-CARDS (reused)
=========================== */
.obj-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
}
.obj-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 18px 20px;
  display: flex; align-items: flex-start; gap: 14px; transition: all 0.3s;
}
.obj-card:hover { border-color: var(--accent); transform: translateY(-4px); box-shadow: 0 12px 30px rgba(56,189,248,0.1); }
.obj-icon {
  width: 38px; height: 38px; min-width: 38px;
  background: linear-gradient(135deg, rgba(56,189,248,0.2), rgba(129,140,248,0.2));
  border-radius: 8px; display: flex; align-items: center; justify-content: center;
  color: var(--accent); font-size: 0.9rem;
}

/* Diff badges */
.diff-easy   { background: rgba(34,197,94,0.15);  color: #22c55e;  border: 1px solid rgba(34,197,94,0.3);  font-size: 0.7rem; padding: 3px 10px; border-radius: 20px; font-weight: 700; }
.diff-medium { background: rgba(245,158,11,0.15); color: #f59e0b;  border: 1px solid rgba(245,158,11,0.3); font-size: 0.7rem; padding: 3px 10px; border-radius: 20px; font-weight: 700; }
.diff-hard   { background: rgba(244,63,94,0.15);  color: #f43f5e;  border: 1px solid rgba(244,63,94,0.3);  font-size: 0.7rem; padding: 3px 10px; border-radius: 20px; font-weight: 700; }

/* Usecase cards */
.usecase-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 26px; text-align: center;
  transition: all 0.35s; height: 100%;
}
.usecase-card:hover {
  border-color: rgba(56,189,248,0.4); transform: translateY(-8px);
  box-shadow: 0 25px 50px rgba(0,0,0,0.3), 0 0 30px rgba(56,189,248,0.08);
}
.uc-icon {
  width: 64px; height: 64px; border-radius: 18px;
  display: flex; align-items: center; justify-content: center;
  font-size: 1.6rem; margin: 0 auto 18px;
}

/* ===========================
   FOOTER
=========================== */
.site-footer {
  background: var(--bg-deep);
  border-top: 1px solid var(--border);
  padding: 50px 0 30px;
}
.footer-grid {
  display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 40px;
  margin-bottom: 40px;
}
.footer-brand-name {
  font-family: 'Syne', sans-serif; font-size: 1.4rem; font-weight: 800;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; margin-bottom: 12px;
}
.footer-tagline { font-size: 0.88rem; color: var(--text-muted); margin-bottom: 20px; }
.footer-social { display: flex; gap: 10px; }
.footer-social-link {
  width: 36px; height: 36px; border-radius: 8px;
  background: var(--bg-card); border: 1px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  color: var(--text-muted); font-size: 0.9rem; text-decoration: none;
  transition: all 0.25s;
}
.footer-social-link:hover { border-color: var(--accent); color: var(--accent); }
.footer-col-title { font-weight: 700; font-size: 0.85rem; margin-bottom: 16px; color: var(--text-main); }
.footer-link {
  display: block; color: var(--text-muted); font-size: 0.85rem;
  text-decoration: none; margin-bottom: 10px; transition: color 0.2s;
}
.footer-link:hover { color: var(--accent); }
.footer-bottom {
  border-top: 1px solid var(--border); padding-top: 24px;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 12px;
}
.footer-copy { font-size: 0.8rem; color: var(--text-dim); }
.footer-love { font-size: 0.85rem; color: var(--text-muted); }
.footer-love a { color: var(--accent); text-decoration: none; }
.footer-love a:hover { color: #818cf8; }

/* ===========================
   BACK TO TOP
=========================== */
#backToTop {
  position: fixed; bottom: 28px; right: 28px; z-index: 999;
  width: 48px; height: 48px; border-radius: 12px;
  background: linear-gradient(135deg, #38bdf8, #818cf8);
  border: none; color: #fff; font-size: 1.1rem;
  cursor: pointer; opacity: 0; transform: translateY(20px);
  transition: all 0.3s; box-shadow: 0 8px 24px rgba(56,189,248,0.35);
}
#backToTop.visible { opacity: 1; transform: translateY(0); }
#backToTop:hover { transform: translateY(-4px); box-shadow: 0 12px 32px rgba(56,189,248,0.5); }

/* ===========================
   SPACING UTILITIES
=========================== */
.section-gap { padding: 80px 0; }
.section-gap-sm { padding: 50px 0; }

/* ===========================
   ANIMATIONS
=========================== */
@keyframes fadeInUp { from{opacity:0;transform:translateY(30px)} to{opacity:1;transform:translateY(0)} }
.animate-hero { animation: fadeInUp 0.8s ease-out forwards; }
.animate-hero-delay-1 { animation: fadeInUp 0.8s 0.2s ease-out both; }
.animate-hero-delay-2 { animation: fadeInUp 0.8s 0.4s ease-out both; }
.animate-hero-delay-3 { animation: fadeInUp 0.8s 0.6s ease-out both; }
.animate-hero-delay-4 { animation: fadeInUp 0.8s 0.8s ease-out both; }

@keyframes arrowPulse { 0%,100%{opacity:1;transform:translateX(0)} 50%{opacity:0.5;transform:translateX(4px)} }
@keyframes blink { 0%,100%{opacity:1} 50%{opacity:0.3} }

.counter-animate .counter-num { transition: none; }

/* ===========================
   RESPONSIVE
=========================== */
@media(max-width: 992px) {
  .roadmap-spine { display: none; }
  .roadmap-item { flex-direction: column !important; align-items: flex-start; padding-left: 20px; }
  .footer-grid { grid-template-columns: 1fr 1fr; }
}
@media(max-width: 768px) {
  .hero-title { font-size: 2.2rem; }
  .floating-badge-1, .floating-badge-2 { display: none; }
  .progress-steps { gap: 0; }
  .ps-label { font-size: 0.62rem; }
  .hero-cta-group { flex-direction: column; }
  .btn-primary-hero, .btn-outline-hero { justify-content: center; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .stats-grid { grid-template-columns: 1fr 1fr; }
  .nav-links-desktop { display: none !important; }
  .nav-hamburger { display: flex !important; }
  .chapters-grid { grid-template-columns: 1fr; }
}
@media(max-width: 480px) {
  .stats-grid { grid-template-columns: 1fr; }
  .inst-stats-grid { grid-template-columns: 1fr; }
  .hero-stats { gap: 8px; }
}