/* ==================== ROOT VARS ==================== */
:root {
  --bg: #0a0e1a;
  --bg-elev: #131826;
  --bg-elev-2: #1c2235;
  --surface: rgba(255,255,255,0.04);
  --border: rgba(255,255,255,0.08);
  --text: #e7ecf3;
  --muted: #8794ab;
  --accent: #7c5cff;
  --accent-2: #00d4ff;
  --accent-3: #ff6b9d;
  --success: #4ade80;
  --warning: #fbbf24;
  --danger: #f87171;
  --grad: linear-gradient(135deg, #7c5cff 0%, #00d4ff 100%);
  --grad-2: linear-gradient(135deg, #ff6b9d 0%, #7c5cff 100%);
  --shadow: 0 8px 24px rgba(0,0,0,0.4);
  --shadow-lg: 0 20px 60px rgba(0,0,0,0.5);
  --radius: 12px;
  --radius-lg: 20px;
}

[data-theme="light"] {
  --bg: #f6f8fc;
  --bg-elev: #ffffff;
  --bg-elev-2: #f0f3f9;
  --surface: rgba(0,0,0,0.02);
  --border: rgba(0,0,0,0.08);
  --text: #1a2030;
  --muted: #5d6b85;
  --shadow: 0 8px 24px rgba(0,0,0,0.06);
  --shadow-lg: 0 20px 60px rgba(0,0,0,0.1);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  display: flex;
  min-height: 100vh;
  transition: background 0.3s, color 0.3s;
}

body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 800px 600px at 10% 0%, rgba(124,92,255,0.10), transparent 70%),
    radial-gradient(ellipse 600px 400px at 90% 100%, rgba(0,212,255,0.08), transparent 70%);
  pointer-events: none;
  z-index: 0;
}

/* ==================== SIDEBAR ==================== */
#sidebar {
  width: 280px;
  background: var(--bg-elev);
  border-right: 1px solid var(--border);
  padding: 1.5rem 1rem;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  z-index: 10;
  flex-shrink: 0;
}

#sidebar::-webkit-scrollbar { width: 6px; }
#sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

.brand {
  display: flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--border);
}

.brand .logo {
  font-size: 2rem;
  filter: drop-shadow(0 0 10px var(--accent));
}

.brand h1 {
  font-size: 1.1rem;
  font-weight: 700;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.brand .sub {
  font-size: 0.7rem;
  color: var(--muted);
  margin-top: 0.1rem;
}

nav { display: flex; flex-direction: column; gap: 0.15rem; }

.nav-section {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--muted);
  margin: 1rem 0.5rem 0.3rem;
  font-weight: 600;
}

.nav-link {
  text-decoration: none;
  color: var(--text);
  padding: 0.5rem 0.75rem;
  border-radius: 8px;
  font-size: 0.875rem;
  transition: all 0.18s ease;
  opacity: 0.75;
  border-left: 2px solid transparent;
}

.nav-link:hover {
  background: var(--surface);
  opacity: 1;
}

.nav-link.active {
  background: var(--surface);
  border-left-color: var(--accent);
  opacity: 1;
  font-weight: 600;
  color: var(--accent-2);
}

.progress-box {
  margin-top: 2rem;
  padding: 1rem;
  background: var(--surface);
  border-radius: 10px;
  border: 1px solid var(--border);
}

.progress-label {
  font-size: 0.75rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

.progress-bar {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  overflow: hidden;
}

#progress-fill {
  height: 100%;
  background: var(--grad);
  width: 0%;
  transition: width 0.4s ease;
}

#progress-text {
  font-size: 0.75rem;
  color: var(--muted);
  margin-top: 0.5rem;
}

#theme-toggle {
  margin-top: 1rem;
  width: 100%;
  padding: 0.5rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  cursor: pointer;
  font-size: 1rem;
  transition: background 0.2s;
}
#theme-toggle:hover { background: var(--bg-elev-2); }

/* ==================== MAIN CONTENT ==================== */
#content {
  flex: 1;
  padding: 3rem 4rem;
  max-width: calc(100vw - 280px);
  position: relative;
  z-index: 1;
}

.section {
  margin-bottom: 5rem;
  padding-top: 2rem;
  scroll-margin-top: 1rem;
  max-width: 1100px;
}

.chapter {
  display: inline-block;
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  padding: 0.3rem 0.8rem;
  background: rgba(124,92,255,0.12);
  border-radius: 100px;
  margin-bottom: 1rem;
  font-weight: 700;
}

h1 { font-size: 3.5rem; line-height: 1.1; letter-spacing: -0.02em; font-weight: 800; }
h2 { font-size: 2.25rem; margin-bottom: 1.5rem; font-weight: 700; letter-spacing: -0.01em; }
h3 { font-size: 1.4rem; margin: 2rem 0 1rem; font-weight: 600; }
h4 { font-size: 1.05rem; margin-bottom: 0.5rem; font-weight: 600; }

.grad {
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

p { margin-bottom: 1rem; }

.intro-text { font-size: 1.05rem; color: var(--muted); margin-bottom: 2rem; }

/* ==================== HERO ==================== */
.hero {
  padding: 3rem 0;
}

.pill {
  display: inline-block;
  padding: 0.4rem 1rem;
  background: var(--grad);
  color: white;
  border-radius: 100px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  margin-bottom: 1.5rem;
  box-shadow: 0 4px 14px rgba(124,92,255,0.4);
}

.lead {
  font-size: 1.2rem;
  color: var(--muted);
  margin-top: 1.5rem;
  margin-bottom: 2rem;
  max-width: 700px;
}

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

/* ==================== BUTTONS ==================== */
.btn {
  display: inline-block;
  padding: 0.7rem 1.4rem;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  border: 1px solid transparent;
  text-decoration: none;
  transition: transform 0.15s, box-shadow 0.15s, background 0.15s;
}

.btn.primary {
  background: var(--grad);
  color: white;
  box-shadow: 0 4px 14px rgba(124,92,255,0.35);
}
.btn.primary:hover { transform: translateY(-2px); box-shadow: 0 8px 20px rgba(124,92,255,0.5); }

.btn.ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
}
.btn.ghost:hover { background: var(--surface); }

.btn.small {
  padding: 0.45rem 0.9rem;
  font-size: 0.85rem;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
}
.btn.small:hover { background: var(--bg-elev-2); }

/* ==================== CARDS ==================== */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 2rem 0;
}

.card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  transition: transform 0.2s, border-color 0.2s;
}

.card:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
}

.card-icon { font-size: 2rem; display: block; margin-bottom: 0.75rem; }

/* ==================== CONCEPT GRID ==================== */
.concept-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.concept {
  background: var(--bg-elev);
  padding: 1.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
}

/* ==================== BOXES ==================== */
.info-box, .warn-box, .remarks {
  background: var(--bg-elev);
  border-left: 4px solid var(--accent-2);
  padding: 1.25rem 1.5rem;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1.5rem 0;
}

.info-box.highlight {
  background: linear-gradient(135deg, rgba(124,92,255,0.10), rgba(0,212,255,0.05));
  border-left-color: var(--accent);
}

.warn-box { border-left-color: var(--warning); background: rgba(251,191,36,0.06); }

.info-box ul, .warn-box ul { padding-left: 1.5rem; margin: 0.5rem 0; }
.info-box li, .warn-box li { margin-bottom: 0.3rem; }

/* ==================== FORMULA ==================== */
.formula-box {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  padding: 1.5rem;
  margin: 1.5rem 0;
  border-radius: var(--radius);
  text-align: center;
  font-size: 1.1rem;
  position: relative;
  overflow-x: auto;
}

.formula-box.highlight {
  background: linear-gradient(135deg, rgba(124,92,255,0.10), rgba(0,212,255,0.05));
  border-color: var(--accent);
}

.formula-box p { text-align: left; font-size: 0.95rem; }

.hl {
  background: linear-gradient(180deg, transparent 60%, rgba(255,107,157,0.3) 60%);
  font-weight: 600;
}

/* ==================== WIDGETS ==================== */
.widget {
  margin: 2rem 0;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow);
}

.widget-header {
  padding: 1.25rem 1.5rem;
  background: linear-gradient(135deg, rgba(124,92,255,0.10), rgba(0,212,255,0.05));
  border-bottom: 1px solid var(--border);
}

.widget-header h4 {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.widget-header p { color: var(--muted); margin: 0.5rem 0 0; font-size: 0.9rem; }

.widget-body { padding: 1.5rem; }

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  align-items: center;
  margin-bottom: 1.25rem;
  padding: 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
}

.controls label {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  font-size: 0.85rem;
  color: var(--muted);
}

.controls select, .controls input[type="number"], .controls input[type="text"] {
  padding: 0.5rem 0.8rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-size: 0.95rem;
  font-family: inherit;
}

.controls input[type="range"] { accent-color: var(--accent); width: 180px; }

/* ==================== CDMA SPREAD VIZ ==================== */
.viz {
  display: grid;
  gap: 1rem;
  margin: 1rem 0;
}
.viz .lbl { font-size: 0.85rem; color: var(--muted); margin-bottom: 0.3rem; }
.viz svg { width: 100%; height: 100px; background: var(--bg); border-radius: 8px; }

.result {
  padding: 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  margin-top: 1rem;
  font-family: 'Courier New', monospace;
  font-size: 0.9rem;
  white-space: pre-wrap;
}

/* ==================== ORTHOGONAL ==================== */
.users-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 0.75rem;
  margin-bottom: 1rem;
}

.user-card {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.85rem;
}

.user-card h5 { font-size: 0.95rem; margin-bottom: 0.5rem; color: var(--accent-2); }

.user-card .code-display {
  font-family: 'Courier New', monospace;
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
  word-break: break-all;
}

.user-card label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
}

.user-card select {
  padding: 0.3rem;
  border-radius: 6px;
  background: var(--bg);
  border: 1px solid var(--border);
  color: var(--text);
}

#orth-result {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  font-size: 0.9rem;
}

#orth-result table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 0.5rem;
}

#orth-result td, #orth-result th {
  padding: 0.4rem 0.7rem;
  border: 1px solid var(--border);
  text-align: center;
  font-family: 'Courier New', monospace;
  font-size: 0.85rem;
}

#orth-result .correct { color: var(--success); font-weight: bold; }

/* ==================== GAIN CALCULATOR ==================== */
.calc-inputs {
  display: grid;
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.calc-inputs label {
  display: grid;
  grid-template-columns: 1fr 2fr auto;
  gap: 1rem;
  align-items: center;
  font-size: 0.95rem;
}

.calc-output {
  background: var(--bg-elev-2);
  padding: 1.25rem;
  border-radius: var(--radius);
  text-align: center;
  font-size: 1.1rem;
  border: 1px solid var(--border);
}

.calc-output .big {
  font-size: 2.2rem;
  font-weight: 700;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ==================== HEXAGONAL ==================== */
.hex-results {
  display: flex;
  gap: 1rem;
  margin-bottom: 1rem;
  flex-wrap: wrap;
}

.hex-result-card {
  flex: 1;
  min-width: 100px;
  background: var(--bg-elev-2);
  padding: 0.85rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  text-align: center;
}

.hex-result-card .lbl { display: block; font-size: 0.75rem; color: var(--muted); margin-bottom: 0.3rem; }
.hex-result-card .val { font-size: 1.5rem; font-weight: 700; color: var(--accent-2); }

#hex-svg { width: 100%; max-height: 500px; background: var(--bg); border-radius: var(--radius); }

.hex-info {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  font-size: 0.9rem;
}

.hex-info ol { padding-left: 1.5rem; }

.motif-examples {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 0.75rem;
  margin: 1rem 0;
}

.motif-ex {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.85rem;
  text-align: center;
  cursor: pointer;
  transition: all 0.15s;
}

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

.motif-ex span {
  display: block;
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent-2);
}

.motif-ex small { color: var(--muted); font-size: 0.75rem; }

/* ==================== DUPLEX TABLE ==================== */
.duplex-table, .canaux-table, .cs-table {
  margin: 1.5rem 0;
  overflow-x: auto;
}

.duplex-table table, .canaux-table table, .cs-table table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-elev);
  border-radius: var(--radius);
  overflow: hidden;
}

.duplex-table th, .canaux-table th, .cs-table th {
  background: var(--bg-elev-2);
  padding: 0.85rem;
  text-align: left;
  border: 1px solid var(--border);
  font-weight: 600;
  font-size: 0.9rem;
}

.duplex-table td, .canaux-table td, .cs-table td {
  padding: 0.85rem;
  border: 1px solid var(--border);
  font-size: 0.9rem;
}

.note { font-size: 0.85rem; color: var(--muted); margin-top: 0.5rem; }

/* Canaux rows */
.cls-bch { background: rgba(124,92,255,0.06); }
.cls-cch { background: rgba(0,212,255,0.06); }
.cls-dch { background: rgba(255,107,157,0.06); }
.cls-tch { background: rgba(74,222,128,0.06); }

.legend {
  background: var(--bg-elev-2);
  padding: 0.85rem;
  border-radius: var(--radius);
  font-size: 0.85rem;
  margin-top: 0.5rem;
}

/* ==================== PROS / CONS ==================== */
.pros-cons {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.pros, .cons {
  background: var(--bg-elev);
  padding: 1.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.pros { border-left: 3px solid var(--success); }
.cons { border-left: 3px solid var(--danger); }

.pros h4 { color: var(--success); }
.cons h4 { color: var(--danger); }

.pros ul, .cons ul { padding-left: 1.5rem; margin-top: 0.5rem; }
.pros li, .cons li { margin-bottom: 0.4rem; }

/* ==================== PHASES ==================== */
.phases {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.85rem;
  margin: 1.25rem 0;
}

.phase {
  background: var(--bg-elev);
  padding: 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  position: relative;
}

.phase-num {
  position: absolute;
  top: -10px;
  left: -10px;
  width: 30px;
  height: 30px;
  background: var(--grad);
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  color: white;
  font-size: 0.9rem;
}

.phase h4 { margin-top: 0.5rem; font-size: 0.95rem; color: var(--accent-2); }
.phase p { font-size: 0.85rem; margin: 0; }

/* ==================== DB CARDS ==================== */
.db-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.db-card {
  background: var(--bg-elev);
  padding: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.db-card.hlr { border-top: 4px solid var(--accent); }
.db-card.vlr { border-top: 4px solid var(--accent-2); }

.db-card h3 { display: flex; align-items: center; gap: 0.5rem; }
.db-card .db-sub { color: var(--muted); font-size: 0.85rem; margin-bottom: 1rem; font-style: italic; }
.db-card h4 { margin-top: 1rem; font-size: 0.95rem; }
.db-card ul { padding-left: 1.5rem; margin-top: 0.5rem; }
.db-card li { margin-bottom: 0.4rem; font-size: 0.9rem; }

/* ==================== ID CARDS ==================== */
.id-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0.85rem;
  margin: 1.25rem 0;
}

.id-card {
  background: var(--bg-elev);
  padding: 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  border-top: 3px solid var(--accent);
}

.id-card h4 {
  color: var(--accent);
  font-size: 1rem;
  font-family: 'Courier New', monospace;
  font-weight: 700;
}

.id-card .sub { font-size: 0.78rem; color: var(--muted); font-style: italic; margin: 0.3rem 0 0.5rem; }

/* ==================== ARCH WIDGET ==================== */
#arch-svg, #gsm-arch-svg, #gprs-svg {
  width: 100%;
  height: 500px;
  background: var(--bg);
  border-radius: var(--radius);
}

.arch-info {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  min-height: 80px;
}

.arch-info h4 { color: var(--accent-2); margin-bottom: 0.4rem; }

/* ==================== HANDOVER ==================== */
#ho-svg, #tdma-svg, #call-svg, #ci-svg {
  width: 100%;
  background: var(--bg);
  border-radius: var(--radius);
}

#ho-svg { height: 280px; }
#tdma-svg { height: 380px; }
#call-svg { height: 420px; }
#ci-svg { height: 400px; }

.ho-controls { display: flex; gap: 1rem; flex-wrap: wrap; margin-bottom: 1rem; align-items: end; }

#ho-status, #ci-result, #call-step-info, #tdma-info, #gain-output {
  margin-top: 1rem;
  padding: 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  font-size: 0.95rem;
}

#tdma-info { min-height: 50px; }

.compare-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.compare-card {
  background: var(--bg-elev);
  padding: 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.compare-tag {
  display: inline-block;
  padding: 0.3rem 0.7rem;
  background: var(--bg-elev-2);
  border-radius: 100px;
  font-size: 0.78rem;
  color: var(--muted);
  margin-bottom: 0.75rem;
}

.compare-card ul { padding-left: 1.4rem; }
.compare-card li { margin-bottom: 0.4rem; font-size: 0.92rem; }

.compare-card .example {
  margin-top: 0.75rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--border);
  font-size: 0.9rem;
  color: var(--muted);
}

/* ==================== SPECS GRID ==================== */
.specs-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.75rem;
  margin: 1rem 0;
}

.spec-card {
  background: var(--bg-elev);
  padding: 0.85rem 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}

.spec-card .lbl { font-size: 0.75rem; color: var(--muted); margin-bottom: 0.35rem; text-transform: uppercase; letter-spacing: 0.05em; }
.spec-card .val { font-size: 0.95rem; font-weight: 600; color: var(--accent-2); }

/* ==================== SUBSYS GRID ==================== */
.subsys-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1rem;
  margin: 1.25rem 0;
}

.subsys-card {
  background: var(--bg-elev);
  padding: 1.25rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  text-align: center;
}

.subsys-card h3 {
  font-size: 1.8rem;
  margin: 0;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subsys-card .sub { font-size: 0.8rem; color: var(--muted); font-style: italic; margin: 0.3rem 0; }

.subsys-card ul { text-align: left; padding-left: 1.5rem; margin-top: 0.5rem; font-size: 0.88rem; }
.subsys-card li { margin-bottom: 0.3rem; }

/* ==================== COMP GRID ==================== */
.comp-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

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

.comp h4 { color: var(--accent-2); margin-bottom: 0.5rem; }
.comp ul { padding-left: 1.4rem; margin-top: 0.5rem; }
.comp li { margin-bottom: 0.4rem; font-size: 0.9rem; }

/* ==================== STEPS ==================== */
.steps { display: grid; gap: 0.5rem; margin: 1rem 0; }

.step {
  padding: 0.75rem 1rem;
  background: var(--bg-elev);
  border-radius: 8px;
  border-left: 3px solid var(--accent);
  font-size: 0.95rem;
}

.step b { color: var(--accent-2); }

.step-info {
  background: var(--bg-elev-2);
  padding: 1rem;
  border-radius: var(--radius);
  margin-top: 1rem;
  min-height: 80px;
  font-size: 0.95rem;
}

.step-info .step-title {
  font-weight: 700;
  color: var(--accent-2);
  display: block;
  margin-bottom: 0.5rem;
}

/* ==================== QUIZ ==================== */
.quiz {
  margin: 2rem 0;
  padding: 1.5rem;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  border-left: 4px solid var(--success);
}

.quiz h4 { margin-bottom: 1rem; color: var(--success); }

.quiz .question {
  margin-bottom: 1.25rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border);
}

.quiz .question:last-of-type { border-bottom: none; }

.quiz .question p { margin-bottom: 0.5rem; }

.quiz .question label {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.5rem 0.7rem;
  border-radius: 8px;
  cursor: pointer;
  margin-bottom: 0.3rem;
  transition: background 0.15s;
}

.quiz .question label:hover { background: var(--bg-elev-2); }

.quiz .question input[type="radio"] { accent-color: var(--accent); }

.quiz .question.correct label.selected { background: rgba(74,222,128,0.15); border-left: 3px solid var(--success); }
.quiz .question.wrong label.selected { background: rgba(248,113,113,0.15); border-left: 3px solid var(--danger); }
.quiz .question.wrong label.show-correct { background: rgba(74,222,128,0.15); border-left: 3px solid var(--success); }

.quiz-result {
  margin-top: 1rem;
  padding: 0.85rem 1rem;
  border-radius: 8px;
  font-weight: 600;
}

.quiz-result.success { background: rgba(74,222,128,0.15); color: var(--success); border-left: 4px solid var(--success); }
.quiz-result.warning { background: rgba(251,191,36,0.15); color: var(--warning); border-left: 4px solid var(--warning); }
.quiz-result.danger { background: rgba(248,113,113,0.15); color: var(--danger); border-left: 4px solid var(--danger); }

/* ==================== GLOSSARY ==================== */
#glossary-search {
  width: 100%;
  padding: 0.85rem 1rem;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 1rem;
  margin: 1rem 0;
  font-family: inherit;
}

.glossary {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 0.75rem;
}

.gloss-entry {
  background: var(--bg-elev);
  padding: 1rem;
  border-radius: 10px;
  border: 1px solid var(--border);
  transition: border-color 0.15s;
}

.gloss-entry:hover { border-color: var(--accent); }

.gloss-entry .term {
  font-family: 'Courier New', monospace;
  color: var(--accent-2);
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 0.2rem;
}

.gloss-entry .expand {
  font-size: 0.78rem;
  color: var(--muted);
  font-style: italic;
  margin-bottom: 0.4rem;
}

.gloss-entry .def { font-size: 0.88rem; line-height: 1.5; }

.gloss-entry.hidden { display: none; }

/* ==================== EXAM ==================== */
#exam-container {
  display: grid;
  gap: 1rem;
  margin: 1.5rem 0;
}

.exam-q {
  background: var(--bg-elev);
  padding: 1.25rem 1.5rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.exam-q .exam-q-num {
  display: inline-block;
  background: var(--grad);
  color: white;
  padding: 0.2rem 0.7rem;
  border-radius: 100px;
  font-size: 0.78rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.exam-q p { font-weight: 500; margin-bottom: 0.5rem; }

.exam-q label {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.5rem 0.7rem;
  border-radius: 8px;
  cursor: pointer;
  margin-bottom: 0.3rem;
}

.exam-q label:hover { background: var(--bg-elev-2); }
.exam-q input[type="radio"] { accent-color: var(--accent); }

.exam-q.correct { border-left: 4px solid var(--success); }
.exam-q.wrong { border-left: 4px solid var(--danger); }

.exam-q.correct label.selected { background: rgba(74,222,128,0.15); }
.exam-q.wrong label.selected { background: rgba(248,113,113,0.15); }
.exam-q.wrong label.show-correct { background: rgba(74,222,128,0.15); }

#exam-result {
  margin-top: 2rem;
  padding: 2rem;
  border-radius: var(--radius);
  text-align: center;
  display: none;
}

#exam-result.shown { display: block; }

#exam-result h3 { font-size: 2rem; margin-bottom: 0.5rem; }

#exam-result .big-score {
  font-size: 4rem;
  font-weight: 800;
  background: var(--grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
  margin: 1rem 0;
}

/* ==================== FOOTER ==================== */
footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  text-align: center;
  color: var(--muted);
  font-size: 0.9rem;
}

footer .footer-small { font-size: 0.8rem; margin-top: 0.5rem; opacity: 0.7; }

/* ==================== ANIMATIONS ==================== */
@keyframes pulse {
  0%, 100% { transform: scale(1); opacity: 1; }
  50% { transform: scale(1.05); opacity: 0.8; }
}

.pulse { animation: pulse 1.5s ease-in-out infinite; }

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-in { animation: fadeIn 0.4s ease forwards; }

@keyframes signalMove {
  from { stroke-dashoffset: 100; }
  to { stroke-dashoffset: 0; }
}

.signal-line {
  stroke-dasharray: 8 4;
  animation: signalMove 1s linear infinite;
}

/* ==================== INTUITION BOXES ==================== */
.intuition {
  margin: 1.25rem 0;
  background: linear-gradient(135deg, rgba(251,191,36,0.10), rgba(255,107,157,0.05));
  border: 1px solid rgba(251,191,36,0.3);
  border-left: 4px solid #fbbf24;
  border-radius: var(--radius);
  padding: 1.1rem 1.4rem;
  position: relative;
}

.intuition::before {
  content: "💡 Intuition";
  display: inline-block;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: #fbbf24;
  margin-bottom: 0.55rem;
  padding: 0.18rem 0.6rem;
  background: rgba(251,191,36,0.15);
  border-radius: 100px;
}

.intuition h4 {
  display: block;
  color: var(--text);
  font-size: 1rem;
  margin: 0.2rem 0 0.5rem;
}

.intuition p { margin: 0.45rem 0; line-height: 1.65; }

.intuition .analogy {
  margin: 0.7rem 0;
  padding: 0.7rem 0.9rem;
  background: rgba(0,0,0,0.15);
  border-left: 2px solid rgba(255,255,255,0.15);
  border-radius: 0 8px 8px 0;
  font-style: italic;
  font-size: 0.95rem;
}

.intuition .analogy::before {
  content: "🎯 ";
  font-style: normal;
}

.intuition .key {
  background: rgba(0,212,255,0.15);
  padding: 0 0.3rem;
  border-radius: 4px;
  color: var(--accent-2);
  font-weight: 600;
}

[data-theme="light"] .intuition {
  background: linear-gradient(135deg, rgba(251,191,36,0.12), rgba(255,107,157,0.05));
}
[data-theme="light"] .intuition .analogy {
  background: rgba(0,0,0,0.04);
}

.kpreview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1rem;
  margin: 1rem 0 0.5rem;
}

.kpreview-card {
  background: rgba(0,0,0,0.15);
  border-radius: 10px;
  padding: 0.85rem;
  text-align: center;
}

.kpreview-card h5 {
  margin: 0 0 0.4rem;
  font-size: 0.95rem;
}

.kpreview-card .kpreview-svg {
  width: 100%;
  height: 180px;
  display: block;
  background: var(--bg);
  border-radius: 8px;
  margin: 0.4rem 0 0.6rem;
}

.kpreview-card p {
  font-size: 0.82rem;
  margin: 0;
  text-align: left;
  color: var(--text);
  line-height: 1.55;
}

[data-theme="light"] .kpreview-card { background: rgba(0,0,0,0.04); }

.cellsize-compare {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  align-items: start;
}

.cellsize-viz .lbl {
  font-size: 0.8rem;
  color: var(--muted);
  text-align: center;
  margin-bottom: 0.4rem;
}

.cellsize-viz svg {
  width: 100%;
  height: 320px;
  background: var(--bg);
  border-radius: 8px;
}

.cellsize-stats {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.cellsize-stats .stat {
  background: var(--bg-elev-2);
  padding: 0.75rem 0.9rem;
  border-radius: 8px;
  border-left: 3px solid var(--accent);
}

.cellsize-stats .stat .lbl {
  font-size: 0.75rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.cellsize-stats .stat .val {
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--accent-2);
}

.cellsize-stats .stat .desc {
  font-size: 0.82rem;
  color: var(--text);
  opacity: 0.85;
  margin-top: 0.2rem;
}

@media (max-width: 700px) {
  .cellsize-compare { grid-template-columns: 1fr; }
}

.chan-flow {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1rem 0;
  min-height: 60px;
  padding: 0.85rem;
  background: var(--bg);
  border-radius: var(--radius);
}

.chan-step {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.25rem;
  padding: 0.5rem 0.7rem;
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 0.85rem;
  position: relative;
  animation: fadeIn 0.3s ease;
}

.chan-step.current {
  background: var(--grad);
  color: white;
  border-color: var(--accent);
  transform: scale(1.05);
  box-shadow: 0 4px 14px rgba(124,92,255,0.4);
}

.chan-step .chan-name {
  font-family: 'Courier New', monospace;
  font-weight: 700;
  font-size: 0.9rem;
}

.chan-step .chan-dir {
  font-size: 0.7rem;
  opacity: 0.85;
}

.chan-step::after {
  content: "→";
  position: absolute;
  right: -16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--muted);
  font-size: 1rem;
}

.chan-step:last-child::after { content: ""; }

#ij-svg {
  width: 100%;
  height: 420px;
  background: var(--bg);
  border-radius: var(--radius);
  margin: 0.5rem 0;
}

.ij-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
  padding: 0.85rem 1rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  font-size: 0.85rem;
}

.ij-legend .lg-item {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.ij-legend .dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: inline-block;
}

.ij-legend .arrow {
  width: 24px;
  height: 4px;
  border-radius: 2px;
  display: inline-block;
}

/* ==================== FORMULA CARDS (Outils) ==================== */
.formula-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 0.85rem;
  margin: 1.5rem 0;
}

.formula-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 1rem 1.2rem;
}

.formula-card h4 {
  font-size: 0.95rem;
  color: var(--accent-2);
  margin-bottom: 0.5rem;
}

.formula-card .formula-line {
  font-size: 1.05rem;
  text-align: center;
  margin: 0.5rem 0;
  padding: 0.4rem 0.3rem;
  background: var(--bg);
  border-radius: 6px;
  overflow-x: auto;
}

.formula-card .formula-note {
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 0.4rem;
  line-height: 1.4;
}

/* ==================== TD EXERCISES ==================== */
.td-exercise {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  margin: 1.5rem 0;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.td-exercise.featured {
  border-left: 4px solid var(--accent);
}

.td-header {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.5rem;
  background: linear-gradient(135deg, rgba(124,92,255,0.10), rgba(0,212,255,0.05));
  border-bottom: 1px solid var(--border);
}

.td-num {
  background: var(--grad);
  color: white;
  padding: 0.3rem 0.85rem;
  border-radius: 8px;
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  white-space: nowrap;
}

.td-header h3 {
  margin: 0;
  font-size: 1.15rem;
  flex: 1;
}

.td-question {
  padding: 1.25rem 1.5rem;
  background: var(--bg-elev-2);
  border-bottom: 1px solid var(--border);
}

.td-question p, .td-question li {
  margin: 0.3rem 0;
}

.td-question ol {
  padding-left: 1.5rem;
}

.toggle-solution {
  margin: 1rem 1.5rem;
  display: inline-block;
}

.td-solution {
  padding: 0 1.5rem 1.5rem 1.5rem;
  display: none;
  border-top: 1px solid var(--border);
  background: rgba(74,222,128,0.03);
}

.td-solution.expanded { display: block; }

.td-solution h4 {
  color: var(--success);
  margin: 1rem 0 0.75rem;
}

.td-solution .conclusion {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  background: rgba(0,212,255,0.08);
  border-left: 3px solid var(--accent-2);
  border-radius: 0 8px 8px 0;
  font-style: italic;
}

.step-table {
  margin: 0.75rem 0;
  display: grid;
  gap: 0.4rem;
}

.step-line {
  display: flex;
  gap: 0.7rem;
  padding: 0.6rem 0.85rem;
  background: var(--bg);
  border-radius: 8px;
  font-size: 0.9rem;
  align-items: flex-start;
}

.step-pill {
  background: var(--grad);
  color: white;
  padding: 0.1rem 0.55rem;
  border-radius: 100px;
  font-size: 0.75rem;
  font-weight: 700;
  white-space: nowrap;
  flex-shrink: 0;
  margin-top: 0.05rem;
}

/* ==================== ANNALES ==================== */
.pdf-link-box {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  padding: 0.85rem 1.2rem;
  background: var(--bg-elev-2);
  border-radius: var(--radius);
  border-left: 3px solid var(--accent-2);
  margin: 1rem 0 2rem;
  font-size: 0.95rem;
}

.pdf-link-box > span:first-child { font-size: 1.5rem; }

.pdf-link-box a {
  color: var(--accent-2);
  text-decoration: none;
  font-weight: 600;
}
.pdf-link-box a:hover { text-decoration: underline; }

.annales-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1rem;
  margin: 1.5rem 0;
}

.annale-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  transition: transform 0.15s, border-color 0.15s;
}

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

.annale-card.highlight {
  border: 2px solid var(--accent);
  background: linear-gradient(135deg, rgba(124,92,255,0.10), rgba(0,212,255,0.05));
}

.annale-card.corr {
  border-left: 4px solid var(--success);
  background: rgba(74,222,128,0.04);
}

.annale-card h4 {
  font-size: 1.05rem;
  color: var(--accent-2);
  margin: 0;
}

.annale-card .annale-meta {
  font-size: 0.78rem;
  color: var(--muted);
  margin: 0;
}

.annale-card .annale-topics {
  font-size: 0.88rem;
  flex: 1;
  margin: 0.3rem 0;
  line-height: 1.45;
}

.annale-card .btn {
  margin-top: auto;
  align-self: flex-start;
}

/* ==================== CALC TOOL ENHANCEMENTS ==================== */
.calc-output .step {
  margin: 0.3rem 0;
  padding: 0.4rem 0.6rem;
  background: var(--bg);
  border-left: 2px solid var(--border);
  color: var(--muted);
  font-size: 0.85rem;
  border-radius: 0 6px 6px 0;
}

.calc-output .final {
  margin-top: 0.85rem;
  padding: 0.75rem 1rem;
  background: linear-gradient(135deg, rgba(124,92,255,0.12), rgba(0,212,255,0.06));
  border-radius: 8px;
  border-left: 3px solid var(--accent);
  font-size: 1.05rem;
}

.calc-output .final .big {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-2);
}

.calc-multi {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: 0.6rem;
  margin-top: 0.75rem;
}

.calc-multi .pill {
  background: var(--bg);
  padding: 0.6rem 0.85rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  text-align: center;
}

.calc-multi .pill .lbl {
  display: block;
  font-size: 0.75rem;
  color: var(--muted);
  margin-bottom: 0.25rem;
}

.calc-multi .pill .val {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--accent-2);
}

/* ==================== RESPONSIVE ==================== */
@media (max-width: 1024px) {
  #content { padding: 2rem; }
}

@media (max-width: 768px) {
  body { flex-direction: column; }
  #sidebar {
    width: 100%;
    height: auto;
    position: relative;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  #content { padding: 1.5rem; max-width: 100%; }
  h1 { font-size: 2.5rem; }
  h2 { font-size: 1.75rem; }
  .calc-inputs label { grid-template-columns: 1fr; }
  nav { display: none; }
  #sidebar.open nav { display: flex; }
}