:root {
  --bg: #f7f6f2;
  --surface: #ffffff;
  --card: #fefefe;
  --border: #e8e4da;
  --border2: #d4cfc3;
  --text: #1a1814;
  --body: #3d3830;
  --muted: #8a8070;
  --dim: #b8b0a0;
  --ink: #2c2820;
  --cyber: #0a84ff;
  --cyber-dim: rgba(10,132,255,0.08);
  --cyber-border: rgba(10,132,255,0.2);
  --cyber-light: #eef5ff;
  --green: #2d7a47;
  --green-dim: rgba(45,122,71,0.08);
  --green-border: rgba(45,122,71,0.2);
  --blue: #1a5fad;
  --blue-dim: rgba(26,95,173,0.07);
  --blue-border: rgba(26,95,173,0.18);
  --red: #c0392b;
  --red-dim: rgba(192,57,43,0.07);
  --red-border: rgba(192,57,43,0.18);
  --purple: #6c3a9e;
  --purple-dim: rgba(108,58,158,0.07);
  --purple-border: rgba(108,58,158,0.2);
  --orange: #d4600a;
  --orange-dim: rgba(212,96,10,0.08);
  --orange-border: rgba(212,96,10,0.2);
}
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: 'Inter', sans-serif; background: var(--bg); color: var(--text); line-height: 1.6; }

/* HEADER */
header {
  background: var(--surface); border-bottom: 1px solid var(--border);
  padding: 0 40px; height: 60px; display: flex; align-items: center;
  justify-content: space-between; position: sticky; top: 0; z-index: 100;
  box-shadow: 0 1px 4px rgba(0,0,0,0.05);
}
.logo { display: flex; align-items: center; gap: 10px; text-decoration: none; }
.logo-icon {
  width: 32px; height: 32px; background: var(--cyber); border-radius: 8px;
  display: flex; align-items: center; justify-content: center;
  font-family: 'JetBrains Mono', monospace; font-size: 13px; font-weight: 700; color: #fff;
}
.logo-text { font-size: 15px; font-weight: 700; color: var(--text); }
.logo-text span { color: var(--cyber); }
.header-meta { display: flex; align-items: center; gap: 20px; }
.prog-wrap { display: flex; align-items: center; gap: 10px; }
.prog-track { width: 140px; height: 6px; background: var(--border); border-radius: 3px; overflow: hidden; }
.prog-fill { height: 100%; background: linear-gradient(90deg, var(--cyber), #30d158); border-radius: 3px; transition: width .5s ease; width: 0%; }
.prog-pct { font-size: 12px; color: var(--cyber); font-weight: 700; min-width: 34px; }
.badge { font-size: 11px; font-weight: 600; padding: 3px 10px; border-radius: 20px; background: var(--cyber-dim); color: var(--cyber); border: 1px solid var(--cyber-border); }

/* LAYOUT */
.shell { display: flex; min-height: calc(100vh - 60px); }

/* SIDEBAR */
.sidebar {
  width: 268px; flex-shrink: 0; border-right: 1px solid var(--border);
  background: var(--surface); padding: 24px 0;
  position: sticky; top: 60px; height: calc(100vh - 60px); overflow-y: auto;
}
.sb-section { font-size: 10px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; color: var(--dim); padding: 0 20px; margin: 20px 0 6px; }
.sb-section:first-child { margin-top: 0; }
.nav-btn {
  display: flex; align-items: center; gap: 10px; padding: 8px 20px;
  width: 100%; border: none; background: none; cursor: pointer;
  font-family: 'Inter', sans-serif; font-size: 13px; font-weight: 500;
  color: var(--muted); text-align: left; transition: all .12s;
}
.nav-btn:hover { color: var(--text); background: var(--cyber-dim); }
.nav-btn.active { color: var(--cyber); background: var(--cyber-dim); border-right: 3px solid var(--cyber); font-weight: 600; }
.nav-btn.done { color: var(--green); }
.nav-btn.done::after { content: '✓'; margin-left: auto; font-size: 12px; color: var(--green); }
.nav-num {
  width: 22px; height: 22px; border-radius: 6px; font-size: 11px; font-weight: 700;
  background: var(--border); color: var(--muted); display: flex; align-items: center; justify-content: center; flex-shrink: 0;
}
.nav-btn.active .nav-num { background: var(--cyber); color: #fff; }
.nav-btn.done .nav-num { background: var(--green-dim); color: var(--green); border: 1px solid var(--green-border); }

/* SIDEBAR MOBILE */
.menu-toggle {
  display: none; flex-direction: column; gap: 5px; background: none;
  border: none; cursor: pointer; padding: 6px;
}
.menu-toggle span { display: block; width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: all .2s; }
.sidebar-overlay { display: none; position: fixed; inset: 0; background: rgba(0,0,0,.4); z-index: 49; }
.sidebar-close { display: none; justify-content: space-between; align-items: center; padding: 16px 20px; border-bottom: 1px solid var(--border); }
.sidebar-close span { font-size: 13px; font-weight: 600; color: var(--muted); }
.sidebar-close button { background: none; border: none; cursor: pointer; font-size: 18px; color: var(--muted); }

/* MAIN */
.main { flex: 1; min-width: 0; padding: 52px 64px 80px; }

/* LESSON */
.lesson { display: none; }
.lesson.active { display: block; animation: fadeUp .28s ease; }
@keyframes fadeUp { from { opacity:0; transform: translateY(10px); } to { opacity:1; transform:translateY(0); } }

.lesson-eyebrow { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.eyebrow-num { font-size: 12px; font-weight: 700; color: var(--cyber); letter-spacing: .06em; }
.eyebrow-dot { width: 4px; height: 4px; background: var(--dim); border-radius: 50%; }
.eyebrow-cat { font-size: 12px; color: var(--muted); font-weight: 500; }

.lesson h2 {
  font-family: 'Lora', serif; font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 600; color: var(--ink); line-height: 1.2; margin-bottom: 14px;
}
.lesson-intro {
  font-size: 1rem; color: var(--muted); max-width: 620px; line-height: 1.75;
  margin-bottom: 36px; padding-left: 14px; border-left: 3px solid var(--cyber);
}

/* PROSE */
.prose { max-width: 760px; }
.prose p { font-size: .95rem; color: var(--body); line-height: 1.8; margin-bottom: 16px; }
.prose h3 { font-family: 'Lora', serif; font-size: 1.25rem; font-weight: 600; color: var(--ink); margin: 32px 0 12px; }
.prose ul, .prose ol { padding-left: 20px; margin-bottom: 16px; }
.prose li { font-size: .93rem; color: var(--body); margin-bottom: 7px; line-height: 1.7; }
.prose strong { color: var(--ink); font-weight: 600; }
.prose code { font-family: 'JetBrains Mono', monospace; font-size: .82em; background: var(--border); color: var(--cyber); padding: 1px 6px; border-radius: 4px; }

/* CALLOUT */
.callout {
  display: flex; gap: 14px; padding: 16px 18px; border-radius: 8px;
  margin: 20px 0; font-size: .92rem; line-height: 1.75; max-width: 760px;
}
.callout-ico { font-size: 18px; flex-shrink: 0; margin-top: 1px; }
.callout-body { flex: 1; }
.callout-body strong { display: block; font-size: .9rem; margin-bottom: 4px; }
.callout-body p { color: #5a5040; margin: 0; font-size: .88rem; }
.callout.tip   { background: var(--blue-dim);   border: 1px solid var(--blue-border); }
.callout.tip   strong { color: var(--blue); }
.callout.warn  { background: var(--orange-dim); border: 1px solid var(--orange-border); }
.callout.warn  strong { color: var(--orange); }
.callout.good  { background: var(--green-dim);  border: 1px solid var(--green-border); }
.callout.good  strong { color: var(--green); }
.callout.error { background: var(--red-dim);    border: 1px solid var(--red-border); }
.callout.error strong { color: var(--red); }
.callout.cyber { background: var(--cyber-dim);  border: 1px solid var(--cyber-border); }
.callout.cyber strong { color: var(--cyber); }

/* CONCEPT GRID */
.grid-2 { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px,1fr)); gap: 14px; margin: 20px 0; max-width: 760px; }
.concept-card { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 18px; }
.concept-tag { font-size: 10px; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; margin-bottom: 7px; }
.concept-card h4 { font-size: .93rem; font-weight: 600; margin-bottom: 5px; color: var(--ink); }
.concept-card p { font-size: .82rem; color: var(--muted); line-height: 1.6; margin: 0; }

/* TABLE */
.tbl-wrap { overflow-x: auto; margin: 18px 0; max-width: 760px; }
table { width: 100%; border-collapse: collapse; font-size: .88rem; }
th { text-align: left; padding: 9px 14px; font-size: 11px; font-weight: 700; letter-spacing: .07em; text-transform: uppercase; color: var(--muted); border-bottom: 2px solid var(--border); background: var(--bg); }
td { padding: 10px 14px; border-bottom: 1px solid var(--border); color: var(--body); vertical-align: top; }
td:first-child { font-family: 'JetBrains Mono', monospace; font-size: .82rem; color: var(--cyber); font-weight: 500; }
tr:last-child td { border-bottom: none; }
tr:hover td { background: var(--cyber-dim); }

/* QUIZ */
.quiz { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 26px; margin: 32px 0; max-width: 760px; }
.quiz-eyebrow { font-size: 10px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; color: var(--cyber); margin-bottom: 12px; }
.quiz-q { font-size: .96rem; font-weight: 600; color: var(--ink); margin-bottom: 18px; line-height: 1.55; }
.quiz-opts { display: flex; flex-direction: column; gap: 9px; }
.quiz-opt {
  background: var(--bg); border: 1px solid var(--border2); border-radius: 6px;
  padding: 11px 15px; cursor: pointer; font-family: 'Inter', sans-serif;
  font-size: .89rem; font-weight: 500; color: var(--muted); text-align: left; transition: all .12s;
}
.quiz-opt:hover:not(:disabled) { border-color: var(--cyber); color: var(--text); background: var(--cyber-light); }
.quiz-opt.correct { border-color: var(--green); color: var(--green); background: var(--green-dim); }
.quiz-opt.wrong   { border-color: var(--red);   color: var(--red);   background: var(--red-dim);   }
.quiz-opt:disabled { cursor: default; }
.quiz-fb { margin-top: 14px; padding: 11px 15px; border-radius: 6px; font-size: .87rem; font-weight: 600; display: none; }
.quiz-fb.show { display: block; }
.quiz-fb.ok  { background: var(--green-dim); color: var(--green); border: 1px solid var(--green-border); }
.quiz-fb.bad { background: var(--red-dim);   color: var(--red);   border: 1px solid var(--red-border);   }

/* SCENARIO CARD */
.scenario {
  background: #1a1814; border-radius: 10px; padding: 24px; margin: 24px 0; max-width: 760px;
  border-left: 4px solid var(--cyber);
}
.scenario-label { font-size: 10px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; color: var(--cyber); margin-bottom: 10px; font-family: 'JetBrains Mono', monospace; }
.scenario p { font-size: .9rem; color: #c9c0b4; line-height: 1.75; margin: 0; font-family: 'JetBrains Mono', monospace; }
.scenario p strong { color: #e6ddd4; }

/* THREAT BANNER */
.rw-banner {
  display: flex; gap: 14px; align-items: flex-start; background: var(--cyber-dim);
  border: 1px solid var(--cyber-border); border-radius: 8px;
  padding: 16px 18px; margin: 20px 0; max-width: 760px;
}
.rw-icon { font-size: 22px; flex-shrink: 0; }
.rw-text strong { font-size: .9rem; color: var(--cyber); display: block; margin-bottom: 4px; }
.rw-text p { font-size: .87rem; color: var(--body); margin: 0; line-height: 1.7; }

/* LESSON NAV */
.lesson-nav { display: flex; gap: 14px; margin-top: 52px; padding-top: 28px; border-top: 1px solid var(--border); }
.btn { padding: 11px 22px; border-radius: 8px; font-family: 'Inter', sans-serif; font-size: .9rem; font-weight: 600; cursor: pointer; border: none; transition: all .15s; }
.btn-prev { background: var(--bg); color: var(--muted); border: 1px solid var(--border2); }
.btn-prev:hover:not(:disabled) { color: var(--text); border-color: var(--text); }
.btn-prev:disabled { opacity: .4; cursor: default; }
.btn-next { background: var(--cyber); color: #fff; }
.btn-next:hover { background: #0070d8; }

/* CHECKLIST */
.checklist { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 22px 26px; margin: 22px 0; max-width: 760px; }
.checklist h4 { font-size: .95rem; font-weight: 700; color: var(--ink); margin-bottom: 14px; }
.check-item { display: flex; align-items: flex-start; gap: 10px; padding: 8px 0; border-bottom: 1px solid var(--border); font-size: .88rem; color: var(--body); line-height: 1.6; }
.check-item:last-child { border-bottom: none; }
.check-item::before { content: '☐'; color: var(--cyber); font-size: 16px; flex-shrink: 0; margin-top: 1px; }

/* MOBILE */
@media (max-width: 860px) {
  header { padding: 0 16px; }
  .menu-toggle { display: flex; }
  .sidebar {
    position: fixed; top: 0; left: -280px; width: 280px; height: 100vh;
    z-index: 50; transition: left .25s ease; padding-top: 0;
  }
  .sidebar.open { left: 0; }
  .sidebar-overlay.open { display: block; }
  .sidebar-close { display: flex; }
  .main { padding: 32px 20px 60px; }
  .prog-track { width: 80px; }
  .badge { display: none; }
}