/* ============================================================
   THE BLUEPRINT — MASTER DESIGN SYSTEM v2
   Blueprint Navy Theme — merged and clean. No overrides.
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=Barlow+Condensed:wght@400;600;700;800;900&family=Barlow:wght@300;400;500;600&family=Share+Tech+Mono&display=swap');

:root {
  /* Core Colors — Blueprint Navy */
  --black:        #02070d;
  --bg:           #071426;
  --bg-card:      #0a1d33;
  --bg-elevated:  #0e2a48;
  --bg-hover:     #143a5e;
  --border:       rgba(56, 217, 255, 0.18);
  --border-light: rgba(180, 232, 255, 0.34);

  /* Text */
  --text-primary:   #f3fbff;
  --text-secondary: #b8cad8;
  --text-muted:     #6f8ba0;

  /* Brand Accents */
  --gold:       #f5b94c;
  --gold-dark:  #b98222;
  --gold-glow:  rgba(245, 185, 76, 0.14);
  --cyan:       #38d9ff;
  --cyan-dark:  #0a8fb0;
  --cyan-glow:  rgba(56, 217, 255, 0.13);

  /* Signal Colors */
  --green:      #31e08b;
  --green-dark: #15965b;
  --green-glow: rgba(49, 224, 139, 0.13);
  --red:        #ff4d63;
  --red-dark:   #b82b3c;
  --red-glow:   rgba(255, 77, 99, 0.13);

  /* Grade Colors */
  --grade-a: #31e08b;
  --grade-b: #f5b94c;
  --grade-c: #ff4d63;

  /* Typography */
  --font-display: 'Barlow Condensed', sans-serif;
  --font-body:    'Barlow', sans-serif;
  --font-mono:    'Share Tech Mono', monospace;

  /* Spacing Scale */
  --space-xs:  4px;
  --space-sm:  8px;
  --space-md:  16px;
  --space-lg:  24px;
  --space-xl:  40px;
  --space-2xl: 64px;
  --space-3xl: 96px;

  /* Border Radius — sharper, engineering feel */
  --radius-sm: 2px;
  --radius-md: 4px;
  --radius-lg: 6px;

  /* Transitions */
  --transition:      0.2s ease;
  --transition-slow: 0.4s ease;

  /* Max widths */
  --max-content: 900px;
  --max-wide:    1200px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background: var(--bg);
}

body {
  color: var(--text-primary);
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  position: relative;
  overflow-x: clip;
  background:
    radial-gradient(circle at 20% 0%, rgba(56,217,255,0.08), transparent 34rem),
    radial-gradient(circle at 88% 12%, rgba(245,185,76,0.06), transparent 28rem),
    linear-gradient(180deg, #071426 0%, #08192c 42%, #06101f 100%);
}

/* Blueprint grid overlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: -2;
  pointer-events: none;
  background-image:
    linear-gradient(rgba(255,255,255,0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.045) 1px, transparent 1px),
    linear-gradient(rgba(56,217,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(56,217,255,0.03) 1px, transparent 1px);
  background-size: 80px 80px, 80px 80px, 20px 20px, 20px 20px;
  mask-image: linear-gradient(to bottom, black 0%, black 72%, transparent 100%);
  -webkit-mask-image: linear-gradient(to bottom, black 0%, black 72%, transparent 100%);
}

/* --- TYPOGRAPHY --- */
h1,h2,h3,h4,h5,h6 {
  font-family: var(--font-display);
  font-weight: 800;
  line-height: 1.1;
  text-transform: uppercase;
  letter-spacing: 0.02em;
}
h1 { font-size: clamp(2.5rem, 8vw, 5rem); }
h2 { font-size: clamp(1.8rem, 4vw, 2.8rem); }
h3 { font-size: clamp(1.3rem, 3vw, 1.8rem); }
h4 { font-size: 1.2rem; }
h5 { font-size: 1rem; letter-spacing: 0.08em; }

p { font-size: 1rem; line-height: 1.7; color: var(--text-secondary); max-width: 68ch; }
p.lead { font-size: 1.15rem; color: var(--text-primary); font-weight: 300; }
a { color: var(--gold); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--cyan); }
strong { color: var(--text-primary); font-weight: 600; }
code {
  font-family: var(--font-mono); font-size: 0.9em; color: var(--cyan);
  background: var(--bg-elevated); padding: 2px 6px; border-radius: var(--radius-sm);
}

/* --- LAYOUT --- */
.container { width: 100%; max-width: var(--max-content); margin: 0 auto; padding: 0 var(--space-lg); }
.container--wide { max-width: var(--max-wide); }
.section { padding: var(--space-3xl) 0; }
.section--sm { padding: var(--space-2xl) 0; }

/* --- NAVIGATION --- */
.site-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(4, 16, 31, 0.95);
  border-bottom: 1px solid rgba(56,217,255,0.24);
  box-shadow: 0 1px 0 rgba(255,255,255,0.04), 0 14px 40px rgba(0,0,0,0.25);
  height: 60px;
  display: flex;
  align-items: center;
}

.site-nav .container { display: flex; align-items: center; justify-content: space-between; max-width: var(--max-wide); }

.nav-logo {
  font-family: var(--font-display); font-weight: 900; font-size: 1.3rem;
  text-transform: uppercase; letter-spacing: 0.1em;
  color: var(--text-primary); text-decoration: none;
  text-shadow: 0 0 18px rgba(56,217,255,0.18);
}
.nav-logo span { color: var(--cyan); }

.nav-links { display: flex; align-items: center; gap: var(--space-lg); list-style: none; }
.nav-links a:not(.btn) {
  font-family: var(--font-display); font-weight: 600; font-size: 0.85rem;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--text-secondary); transition: color var(--transition);
}
.nav-links a:not(.btn):hover, .nav-links a.active { color: var(--cyan); }

.nav-progress-bar {
  position: absolute; bottom: 0; left: 0; height: 2px;
  background: linear-gradient(90deg, var(--cyan), var(--gold));
  transition: width 0.5s ease; width: 0%;
}

/* --- HAMBURGER MENU --- */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px; height: 36px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  cursor: pointer;
  padding: 8px;
  transition: border-color var(--transition);
  flex-shrink: 0;
}
.nav-hamburger:hover { border-color: rgba(56,217,255,0.5); }
.nav-hamburger span {
  display: block; width: 100%; height: 2px;
  background: var(--text-secondary); border-radius: 2px;
  transition: all 0.3s ease; transform-origin: center;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); background: var(--cyan); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); background: var(--cyan); }

.nav-mobile-menu {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #040c18;
  z-index: 9999;
  flex-direction: column;
  padding: 80px 32px 40px;
  overflow-y: auto;
}
.nav-mobile-menu.open {
  display: flex !important;
}

.nav-mobile-links { list-style: none; display: flex; flex-direction: column; gap: 2px; flex: 1; }
.nav-mobile-links li a {
  display: flex; align-items: center; justify-content: space-between;
  padding: var(--space-md) var(--space-lg);
  font-family: var(--font-display); font-weight: 700; font-size: 1.1rem;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--text-secondary); text-decoration: none;
  border-radius: var(--radius-md); transition: all var(--transition);
  border: 1px solid transparent;
}
.nav-mobile-links li a:hover, .nav-mobile-links li a.active {
  color: var(--cyan);
  background: rgba(56,217,255,0.06);
  border-color: rgba(56,217,255,0.24);
}
.nav-mobile-links li a::after { content: '→'; font-size: 0.9rem; opacity: 0.4; transition: opacity var(--transition); }
.nav-mobile-links li a:hover::after { opacity: 1; }

.nav-mobile-cta { padding-top: var(--space-xl); border-top: 1px solid var(--border); margin-top: var(--space-lg); }
.nav-mobile-cta .btn { width: 100%; justify-content: center; font-size: 1rem; padding: 16px; }

/* --- BUTTONS --- */
.btn {
  display: inline-flex; align-items: center; gap: var(--space-sm);
  font-family: var(--font-display); font-weight: 700; font-size: 0.9rem;
  letter-spacing: 0.1em; text-transform: uppercase;
  padding: 14px 28px; border-radius: var(--radius-md);
  border: none; cursor: pointer; transition: all var(--transition);
  text-decoration: none; white-space: nowrap;
}
.btn--primary {
  background: linear-gradient(90deg, var(--gold), #ffd27a);
  color: #06101f;
  border: 1px solid rgba(255,255,255,0.2);
}
.btn--primary:hover {
  transform: translateY(-1px);
  box-shadow: 0 8px 24px rgba(245,185,76,0.25);
  color: #06101f;
}
.btn--outline {
  background: transparent; color: var(--cyan);
  border: 1px solid rgba(56,217,255,0.4);
}
.btn--outline:hover {
  background: rgba(56,217,255,0.08); color: var(--cyan);
  border-color: var(--cyan);
}
.btn--ghost {
  background: rgba(6,20,38,0.56); color: var(--text-secondary);
  border: 1px solid rgba(56,217,255,0.22);
}
.btn--ghost:hover {
  border-color: rgba(56,217,255,0.5); color: var(--text-primary);
  background: rgba(56,217,255,0.06);
}
.btn--sm { padding: 8px 16px; font-size: 0.8rem; }
.btn--lg { padding: 18px 40px; font-size: 1rem; }

/* --- CARDS --- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  transition: border-color var(--transition);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.04);
}
.card:hover { border-color: rgba(56,217,255,0.4); }

.card--gold { border-color: rgba(245,185,76,0.3); background: linear-gradient(135deg, var(--bg-card), rgba(245,185,76,0.04)); }
.card--cyan { border-color: rgba(56,217,255,0.3); background: linear-gradient(135deg, var(--bg-card), var(--cyan-glow)); }
.card--green { border-color: rgba(49,224,139,0.3); background: linear-gradient(135deg, var(--bg-card), var(--green-glow)); }
.card--red { border-color: rgba(255,77,99,0.3); background: linear-gradient(135deg, var(--bg-card), var(--red-glow)); }

/* --- DIVIDER --- */
.divider { width: 100%; height: 1px; background: var(--border); margin: var(--space-xl) 0; }
.divider--gold { background: linear-gradient(90deg, transparent, var(--cyan), var(--gold), transparent); }

/* --- BADGES --- */
.badge {
  display: inline-block; font-family: var(--font-display); font-weight: 700;
  font-size: 0.7rem; letter-spacing: 0.12em; text-transform: uppercase;
  padding: 4px 10px; border-radius: var(--radius-sm);
}
.badge--gold  { background: var(--gold-glow);  color: var(--gold);  border: 1px solid rgba(245,185,76,0.4); }
.badge--cyan  { background: var(--cyan-glow);  color: var(--cyan);  border: 1px solid rgba(56,217,255,0.4); }
.badge--green { background: var(--green-glow); color: var(--green); border: 1px solid rgba(49,224,139,0.4); }
.badge--red   { background: var(--red-glow);   color: var(--red);   border: 1px solid rgba(255,77,99,0.4); }

/* --- EYEBROW --- */
.eyebrow {
  font-family: var(--font-mono); font-weight: 700; font-size: 0.75rem;
  letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--cyan); margin-bottom: var(--space-sm);
}

/* --- CALLOUTS --- */
.callout {
  border-left: 3px solid var(--gold); background: var(--gold-glow);
  padding: var(--space-md) var(--space-lg);
  border-radius: 0 var(--radius-md) var(--radius-md) 0;
  margin: var(--space-lg) 0;
}
.callout--cyan  { border-color: var(--cyan);  background: var(--cyan-glow); }
.callout--green { border-color: var(--green); background: var(--green-glow); }
.callout--red   { border-color: var(--red);   background: var(--red-glow); }
.callout-title {
  font-family: var(--font-display); font-weight: 800; font-size: 0.8rem;
  letter-spacing: 0.15em; text-transform: uppercase; margin-bottom: var(--space-xs);
}

/* --- GLOSSARY TERM --- */
.glossary-term { color: var(--cyan); border-bottom: 1px dashed var(--cyan-dark); cursor: help; }

/* --- CHECKLIST --- */
.checklist { list-style: none; display: flex; flex-direction: column; gap: var(--space-sm); }
.checklist li {
  display: flex; align-items: flex-start; gap: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  background: var(--bg-elevated); border: 1px solid var(--border);
  border-radius: var(--radius-md); cursor: pointer;
  transition: all var(--transition); font-size: 0.95rem;
  color: var(--text-secondary); user-select: none;
}
.checklist li:hover { border-color: rgba(56,217,255,0.35); color: var(--text-primary); }
.checklist li.checked { border-color: rgba(49,224,139,0.4); background: var(--green-glow); color: var(--text-primary); }
.check-box {
  width: 18px; height: 18px; min-width: 18px;
  border: 2px solid var(--border-light); border-radius: 2px;
  transition: all var(--transition); margin-top: 2px;
  display: flex; align-items: center; justify-content: center;
}
.checklist li.checked .check-box { background: var(--green); border-color: var(--green); }
.check-icon { display: none; color: black; font-size: 11px; font-weight: 900; }
.checklist li.checked .check-icon { display: block; }

/* --- QUIZ --- */
.quiz-option {
  display: block; width: 100%; text-align: left;
  background: var(--bg-elevated); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: var(--space-md) var(--space-lg);
  color: var(--text-secondary); font-family: var(--font-body);
  font-size: 0.95rem; cursor: pointer; transition: all var(--transition);
  margin-bottom: var(--space-sm);
}
.quiz-option:hover:not(:disabled) { border-color: rgba(245,185,76,0.4); color: var(--text-primary); }
.quiz-option.correct { border-color: var(--green); background: var(--green-glow); color: var(--green); }
.quiz-option.incorrect { border-color: var(--red); background: var(--red-glow); color: var(--red); }

/* --- STEP FLOW --- */
.step-flow { display: grid; grid-template-columns: repeat(6,1fr); gap: var(--space-sm); margin: var(--space-xl) 0; }
.step-box {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: var(--space-md) var(--space-sm); text-align: center;
}
.step-box .step-num { font-family: var(--font-display); font-weight: 900; font-size: 1.8rem; color: var(--gold); line-height: 1; }
.step-box .step-title { font-family: var(--font-display); font-weight: 700; font-size: 0.75rem; letter-spacing: 0.08em; text-transform: uppercase; color: var(--text-primary); margin: var(--space-xs) 0; }
.step-box .step-desc { font-size: 0.75rem; color: var(--text-muted); line-height: 1.3; }

/* --- GRADE CARDS --- */
.grade-cards { display: grid; grid-template-columns: repeat(3,1fr); gap: var(--space-md); margin: var(--space-lg) 0; }
.grade-card { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: var(--space-lg); }
.grade-card .grade-letter { font-family: var(--font-display); font-weight: 900; font-size: 2.5rem; line-height: 1; margin-bottom: var(--space-sm); }
.grade-card.a-plus .grade-letter { color: var(--grade-a); }
.grade-card.b-grade .grade-letter { color: var(--grade-b); }
.grade-card.c-grade .grade-letter { color: var(--grade-c); }
.grade-card ul { padding-left: var(--space-lg); display: flex; flex-direction: column; gap: var(--space-xs); }
.grade-card ul li { font-size: 0.85rem; color: var(--text-secondary); }

/* --- KILL SWITCH --- */
.kill-switch {
  background: var(--bg-card); border: 2px solid rgba(255,77,99,0.5);
  border-radius: var(--radius-lg); padding: var(--space-lg);
  display: flex; gap: var(--space-lg); align-items: flex-start;
}
.kill-switch-icon { font-size: 2rem; line-height: 1; flex-shrink: 0; }
.kill-switch-title {
  font-family: var(--font-display); font-weight: 800; font-size: 1rem;
  letter-spacing: 0.1em; text-transform: uppercase;
  color: var(--red); margin-bottom: var(--space-sm);
}

/* --- FOOTER --- */
.site-footer {
  border-top: 1px solid rgba(56,217,255,0.22);
  padding: var(--space-xl) 0; margin-top: var(--space-3xl);
  background: rgba(4,16,31,0.62);
}
.footer-tagline {
  font-family: var(--font-display); font-weight: 600; font-size: 0.85rem;
  letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--text-muted); text-align: center;
}
.footer-tagline span { color: var(--cyan); }

/* --- UTILITIES --- */
.text-gold   { color: var(--gold); }
.text-cyan   { color: var(--cyan); }
.text-green  { color: var(--green); }
.text-red    { color: var(--red); }
.text-muted  { color: var(--text-muted); }
.text-center { text-align: center; }
.text-upper  { text-transform: uppercase; letter-spacing: 0.08em; }
.mt-sm{margin-top:var(--space-sm)}.mt-md{margin-top:var(--space-md)}.mt-lg{margin-top:var(--space-lg)}.mt-xl{margin-top:var(--space-xl)}
.mb-sm{margin-bottom:var(--space-sm)}.mb-md{margin-bottom:var(--space-md)}.mb-lg{margin-bottom:var(--space-lg)}.mb-xl{margin-bottom:var(--space-xl)}
.flex{display:flex}.flex-center{display:flex;align-items:center;justify-content:center}
.gap-sm{gap:var(--space-sm)}.gap-md{gap:var(--space-md)}.gap-lg{gap:var(--space-lg)}
.grid-2{display:grid;grid-template-columns:1fr 1fr;gap:var(--space-lg)}
.grid-3{display:grid;grid-template-columns:1fr 1fr 1fr;gap:var(--space-lg)}

/* --- RESPONSIVE --- */
@media(max-width:768px){
  .step-flow{grid-template-columns:repeat(3,1fr)}
  .grade-cards{grid-template-columns:1fr}
  .grid-2,.grid-3{grid-template-columns:1fr}
  .nav-links{display:none}
  .nav-hamburger{display:flex}
  body::before{background-size:64px 64px,64px 64px,16px 16px,16px 16px}
}
@media(max-width:480px){
  .step-flow{grid-template-columns:repeat(2,1fr)}
  .container{padding:0 var(--space-md)}
}
@media(min-width:769px){
  .nav-mobile-menu{display:none !important}
}

/* --- ANIMATIONS --- */
@keyframes fadeUp{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}
@keyframes fadeIn{from{opacity:0}to{opacity:1}}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:0.5}}
.animate-fade-up{animation:fadeUp 0.6s ease forwards}
.animate-fade-in{animation:fadeIn 0.4s ease forwards}
.stagger>*{opacity:0}
.stagger>*:nth-child(1){animation:fadeUp 0.6s ease 0.1s forwards}
.stagger>*:nth-child(2){animation:fadeUp 0.6s ease 0.2s forwards}
.stagger>*:nth-child(3){animation:fadeUp 0.6s ease 0.3s forwards}
.stagger>*:nth-child(4){animation:fadeUp 0.6s ease 0.4s forwards}
.stagger>*:nth-child(5){animation:fadeUp 0.6s ease 0.5s forwards}
.stagger>*:nth-child(6){animation:fadeUp 0.6s ease 0.6s forwards}

/* --- SCROLL REVEAL --- */
.scroll-reveal{opacity:0;transform:translateY(24px);transition:opacity 0.6s ease,transform 0.6s ease}
.scroll-reveal.visible{opacity:1;transform:translateY(0)}

/* --- SKIP LINK (injected by js/nav.js) --- */
.skip-link {
  position: absolute; left: -9999px; top: 8px; z-index: 1000;
  padding: var(--space-sm) var(--space-md);
  background: var(--gold); color: var(--bg);
  font-family: var(--font-display); font-weight: 700; letter-spacing: 0.04em;
  text-decoration: none;
}
.skip-link:focus { left: var(--space-sm); }
#main-content:focus { outline: none; }