/* ============================================================
   HYBRID PQC FILE TRANSFER – GLOBAL DESIGN SYSTEM
   Dark Navy Theme | Cyan + Purple Accents | Glassmorphism
   ============================================================ */

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

/* ─── CSS Custom Properties ─── */
:root {
  /* Colors */
  --bg-primary:    #07090f;
  --bg-secondary:  #0d1117;
  --bg-surface:    #111827;
  --bg-elevated:   #1a2235;
  --bg-glass:      rgba(17, 24, 39, 0.7);

  --cyan:          #06b6d4;
  --cyan-light:    #67e8f9;
  --cyan-dark:     #0891b2;
  --cyan-glow:     rgba(6, 182, 212, 0.25);

  --purple:        #8b5cf6;
  --purple-light:  #c4b5fd;
  --purple-dark:   #7c3aed;
  --purple-glow:   rgba(139, 92, 246, 0.25);

  --green:         #10b981;
  --green-glow:    rgba(16, 185, 129, 0.2);
  --red:           #ef4444;
  --red-glow:      rgba(239, 68, 68, 0.2);
  --amber:         #f59e0b;

  --text-primary:  #f1f5f9;
  --text-secondary:#94a3b8;
  --text-muted:    #475569;
  --text-code:     #e2e8f0;

  --border:        rgba(255, 255, 255, 0.07);
  --border-active: rgba(6, 182, 212, 0.4);

  /* Spacing */
  --sp-1: 0.25rem; --sp-2: 0.5rem;  --sp-3: 0.75rem;
  --sp-4: 1rem;    --sp-5: 1.25rem; --sp-6: 1.5rem;
  --sp-8: 2rem;    --sp-10: 2.5rem; --sp-12: 3rem;
  --sp-16: 4rem;   --sp-20: 5rem;   --sp-24: 6rem;

  /* Typography */
  --font-sans: 'Inter', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --font-display: 'Outfit', 'Inter', sans-serif;

  /* Borders */
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 18px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Shadows */
  --shadow-sm:   0 2px 8px rgba(0,0,0,0.4);
  --shadow-md:   0 4px 20px rgba(0,0,0,0.5);
  --shadow-lg:   0 8px 40px rgba(0,0,0,0.6);
  --shadow-cyan: 0 0 30px rgba(6, 182, 212, 0.2);
  --shadow-purple: 0 0 30px rgba(139, 92, 246, 0.2);

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);

  /* Layout */
  --max-width: 1280px;
  --nav-height: 72px;
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
  font-size: 16px;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

/* ─── Navigation ─── */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--nav-height);
  background: rgba(7, 9, 15, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border);
  z-index: 1000;
  transition: background var(--transition-base);
}

.nav.scrolled {
  background: rgba(7, 9, 15, 0.97);
  border-bottom-color: rgba(6, 182, 212, 0.15);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--sp-6);
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  text-decoration: none;
}

.nav-logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--cyan), var(--purple));
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 16px;
  box-shadow: var(--shadow-cyan);
}

.nav-logo-text {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 800;
  background: linear-gradient(90deg, var(--cyan), var(--purple));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  padding: var(--sp-2) var(--sp-3);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: rgba(255,255,255,0.06);
}

.nav-links a.active { color: var(--cyan); }

.nav-cta {
  background: linear-gradient(135deg, var(--cyan-dark), var(--purple-dark)) !important;
  color: white !important;
  padding: var(--sp-2) var(--sp-4) !important;
  border-radius: var(--radius-full) !important;
  font-weight: 600 !important;
  box-shadow: 0 0 20px var(--cyan-glow);
}

.nav-cta:hover {
  box-shadow: 0 0 30px var(--cyan-glow), 0 0 30px var(--purple-glow) !important;
  transform: translateY(-1px);
}

.nav-hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: var(--sp-2);
  background: none;
  border: none;
}

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

.nav-mobile {
  display: none;
  position: fixed;
  top: var(--nav-height);
  left: 0; right: 0;
  background: rgba(7, 9, 15, 0.98);
  border-bottom: 1px solid var(--border);
  padding: var(--sp-4) var(--sp-6);
  z-index: 999;
  backdrop-filter: blur(20px);
}

.nav-mobile.open { display: block; }

.nav-mobile a {
  display: block;
  padding: var(--sp-3) var(--sp-4);
  text-decoration: none;
  color: var(--text-secondary);
  font-weight: 500;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.nav-mobile a:hover { color: var(--cyan); background: rgba(6,182,212,0.08); }

/* ─── Layout Containers ─── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--sp-6);
}

.section { padding: var(--sp-24) 0; }
.section-sm { padding: var(--sp-16) 0; }

/* ─── Typography ─── */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(1.8rem, 4vw, 3rem); }
h3 { font-size: clamp(1.3rem, 2.5vw, 1.8rem); }
h4 { font-size: 1.2rem; font-weight: 700; }
h5 { font-size: 1rem; font-weight: 600; font-family: var(--font-sans); }

p { color: var(--text-secondary); font-size: 0.975rem; line-height: 1.75; }
p.lead { font-size: 1.125rem; color: var(--text-primary); }

.gradient-text {
  background: linear-gradient(135deg, var(--cyan) 0%, var(--purple) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.gradient-text-reverse {
  background: linear-gradient(135deg, var(--purple) 0%, var(--cyan) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-label {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--cyan);
  background: rgba(6, 182, 212, 0.1);
  border: 1px solid rgba(6, 182, 212, 0.25);
  padding: var(--sp-1) var(--sp-3);
  border-radius: var(--radius-full);
  margin-bottom: var(--sp-4);
}

.section-header {
  text-align: center;
  margin-bottom: var(--sp-16);
}

.section-header h2 { margin-bottom: var(--sp-4); }
.section-header p { max-width: 620px; margin: 0 auto; font-size: 1.05rem; }

/* ─── Buttons ─── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 0.75rem 1.75rem;
  border-radius: var(--radius-full);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  border: none;
  text-decoration: none;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
  white-space: nowrap;
}

.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,0.1);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.btn:hover::after { opacity: 1; }

.btn-primary {
  background: linear-gradient(135deg, var(--cyan-dark), var(--purple-dark));
  color: white;
  box-shadow: 0 4px 20px var(--cyan-glow), 0 4px 20px var(--purple-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px var(--cyan-glow), 0 8px 30px var(--purple-glow);
}

.btn-secondary {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--border);
  backdrop-filter: blur(10px);
}

.btn-secondary:hover {
  border-color: var(--cyan);
  color: var(--cyan);
  background: rgba(6,182,212,0.06);
}

.btn-cyan {
  background: rgba(6,182,212,0.15);
  color: var(--cyan);
  border: 1px solid rgba(6,182,212,0.3);
}

.btn-cyan:hover {
  background: rgba(6,182,212,0.25);
  box-shadow: 0 0 20px var(--cyan-glow);
}

.btn-purple {
  background: rgba(139,92,246,0.15);
  color: var(--purple-light);
  border: 1px solid rgba(139,92,246,0.3);
}

.btn-purple:hover {
  background: rgba(139,92,246,0.25);
  box-shadow: 0 0 20px var(--purple-glow);
}

.btn-success {
  background: rgba(16,185,129,0.15);
  color: var(--green);
  border: 1px solid rgba(16,185,129,0.3);
}

.btn-success:hover { background: rgba(16,185,129,0.25); }

.btn-lg { padding: 1rem 2.25rem; font-size: 1rem; }
.btn-sm { padding: 0.5rem 1.1rem; font-size: 0.8rem; }
.btn-full { width: 100%; justify-content: center; }

.btn:disabled, .btn[disabled] {
  opacity: 0.45;
  cursor: not-allowed;
  pointer-events: none;
}

/* ─── Cards ─── */
.card {
  background: var(--bg-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-6);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}

.card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(6,182,212,0.03) 0%, rgba(139,92,246,0.03) 100%);
  pointer-events: none;
}

.card:hover {
  border-color: rgba(6,182,212,0.2);
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg), 0 0 40px rgba(6,182,212,0.08);
}

.card-cyan {
  border-color: rgba(6,182,212,0.2);
  background: rgba(6,182,212,0.04);
}

.card-purple {
  border-color: rgba(139,92,246,0.2);
  background: rgba(139,92,246,0.04);
}

.card-green {
  border-color: rgba(16,185,129,0.2);
  background: rgba(16,185,129,0.04);
}

.card-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: var(--sp-4);
}

.card-icon-cyan  { background: rgba(6,182,212,0.12);  box-shadow: 0 0 20px rgba(6,182,212,0.15); }
.card-icon-purple { background: rgba(139,92,246,0.12); box-shadow: 0 0 20px rgba(139,92,246,0.15); }
.card-icon-green  { background: rgba(16,185,129,0.12); box-shadow: 0 0 20px rgba(16,185,129,0.15); }
.card-icon-amber  { background: rgba(245,158,11,0.12); box-shadow: 0 0 20px rgba(245,158,11,0.15); }

.card h4 { margin-bottom: var(--sp-2); }
.card p  { font-size: 0.875rem; }

/* ─── Grid Layouts ─── */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--sp-6); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--sp-6); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-6); }
.grid-auto { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--sp-6); }

/* ─── Badges ─── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-1);
  padding: 3px 10px;
  border-radius: var(--radius-full);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.badge-cyan   { background: rgba(6,182,212,0.12);  color: var(--cyan);         border: 1px solid rgba(6,182,212,0.25); }
.badge-purple { background: rgba(139,92,246,0.12); color: var(--purple-light); border: 1px solid rgba(139,92,246,0.25); }
.badge-green  { background: rgba(16,185,129,0.12); color: var(--green);         border: 1px solid rgba(16,185,129,0.25); }
.badge-amber  { background: rgba(245,158,11,0.12); color: var(--amber);         border: 1px solid rgba(245,158,11,0.25); }
.badge-red    { background: rgba(239,68,68,0.12);  color: var(--red);           border: 1px solid rgba(239,68,68,0.25); }

.badge::before {
  content: '';
  width: 6px; height: 6px;
  border-radius: 50%;
  background: currentColor;
}

/* ─── Code Blocks ─── */
pre, code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
}

code {
  background: rgba(6,182,212,0.1);
  color: var(--cyan-light);
  padding: 2px 6px;
  border-radius: 4px;
}

pre {
  background: #0d1117;
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  padding: var(--sp-5);
  overflow-x: auto;
  line-height: 1.65;
  position: relative;
}

pre code {
  background: none;
  color: var(--text-code);
  padding: 0;
  border-radius: 0;
}

.code-block-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-bottom: none;
  padding: var(--sp-3) var(--sp-5);
  border-radius: var(--radius-md) var(--radius-md) 0 0;
}

.code-block-header + pre {
  border-top: none;
  border-radius: 0 0 var(--radius-md) var(--radius-md);
  margin-top: 0;
}

.code-lang {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.btn-copy {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-muted);
  padding: 3px 10px;
  border-radius: var(--radius-sm);
  font-size: 0.72rem;
  cursor: pointer;
  font-family: var(--font-sans);
  transition: all var(--transition-fast);
}

.btn-copy:hover { color: var(--cyan); border-color: var(--cyan); background: rgba(6,182,212,0.06); }

/* ─── Accordion ─── */
.accordion { border-radius: var(--radius-lg); overflow: hidden; background: var(--bg-glass); border: 1px solid var(--border); }

.accordion-item { border-bottom: 1px solid var(--border); }
.accordion-item:last-child { border-bottom: none; }

.accordion-header {
  width: 100%;
  background: none;
  border: none;
  padding: var(--sp-5) var(--sp-6);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-4);
  text-align: left;
  transition: background var(--transition-fast);
  color: var(--text-primary);
}

.accordion-header:hover { background: rgba(255,255,255,0.03); }
.accordion-header.active { color: var(--cyan); }

.accordion-title { font-weight: 600; font-size: 0.975rem; }
.accordion-icon { flex-shrink: 0; transition: transform var(--transition-base); color: var(--text-muted); font-size: 1.2rem; }
.accordion-header.active .accordion-icon { transform: rotate(180deg); color: var(--cyan); }

.accordion-body {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
}

.accordion-body.open { max-height: 2000px; }
.accordion-body-inner { padding: 0 var(--sp-6) var(--sp-6); }

/* ─── Info Boxes ─── */
.info-box {
  border-radius: var(--radius-md);
  padding: var(--sp-4) var(--sp-5);
  display: flex;
  gap: var(--sp-3);
  align-items: flex-start;
  margin: var(--sp-6) 0;
}

.info-box-icon { font-size: 1.2rem; flex-shrink: 0; margin-top: 2px; }
.info-box-content p { margin: 0; font-size: 0.875rem; }
.info-box-content h5 { margin-bottom: var(--sp-2); }

.info-box-cyan   { background: rgba(6,182,212,0.08);  border: 1px solid rgba(6,182,212,0.2);  }
.info-box-purple { background: rgba(139,92,246,0.08); border: 1px solid rgba(139,92,246,0.2); }
.info-box-green  { background: rgba(16,185,129,0.08); border: 1px solid rgba(16,185,129,0.2); }
.info-box-amber  { background: rgba(245,158,11,0.08); border: 1px solid rgba(245,158,11,0.2); }

/* ─── Dividers ─── */
.divider {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border), transparent);
  margin: var(--sp-8) 0;
}

.divider-gradient {
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--cyan), var(--purple), transparent);
  opacity: 0.4;
}

/* ─── Tabs ─── */
.tab-group { display: flex; gap: var(--sp-1); background: var(--bg-surface); padding: 4px; border-radius: var(--radius-md); border: 1px solid var(--border); width: fit-content; }

.tab-btn {
  padding: var(--sp-2) var(--sp-4);
  border-radius: var(--radius-sm);
  border: none;
  background: none;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-family: var(--font-sans);
}

.tab-btn:hover { color: var(--text-primary); background: rgba(255,255,255,0.04); }
.tab-btn.active { background: var(--bg-elevated); color: var(--cyan); box-shadow: var(--shadow-sm); }

.tab-content { display: none; }
.tab-content.active { display: block; }

/* ─── Stats / Metric Cards ─── */
.stat-card {
  text-align: center;
  padding: var(--sp-6);
  background: var(--bg-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  backdrop-filter: blur(10px);
}

.stat-card .stat-number {
  font-family: var(--font-display);
  font-size: 2.5rem;
  font-weight: 900;
  line-height: 1;
  margin-bottom: var(--sp-2);
}

.stat-card .stat-label { font-size: 0.8rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.08em; }

/* ─── Table ─── */
.table-wrapper {
  overflow-x: auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border);
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
}

th {
  background: var(--bg-elevated);
  padding: var(--sp-3) var(--sp-5);
  text-align: left;
  font-weight: 600;
  color: var(--text-secondary);
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  white-space: nowrap;
}

td {
  padding: var(--sp-3) var(--sp-5);
  border-top: 1px solid var(--border);
  color: var(--text-secondary);
  vertical-align: middle;
}

tr:hover td { background: rgba(255,255,255,0.02); }
td.highlight { color: var(--text-primary); font-weight: 500; }
td.cyan { color: var(--cyan); font-weight: 600; }
td.purple { color: var(--purple-light); font-weight: 600; }
td.green { color: var(--green); font-weight: 600; }

/* ─── Hero ─── */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  overflow: hidden;
  padding-top: var(--nav-height);
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 80% 60% at 50% -10%, rgba(6,182,212,0.12) 0%, transparent 60%),
              radial-gradient(ellipse 60% 50% at 90% 50%, rgba(139,92,246,0.08) 0%, transparent 60%),
              radial-gradient(ellipse 50% 40% at 10% 80%, rgba(6,182,212,0.06) 0%, transparent 60%);
}

.hero-content {
  position: relative;
  z-index: 2;
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
  padding: var(--sp-20) var(--sp-6);
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: var(--sp-2) var(--sp-4);
  background: rgba(6,182,212,0.1);
  border: 1px solid rgba(6,182,212,0.25);
  border-radius: var(--radius-full);
  font-size: 0.8rem;
  color: var(--cyan);
  font-weight: 600;
  margin-bottom: var(--sp-6);
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.hero-badge-dot {
  width: 8px; height: 8px;
  background: var(--cyan);
  border-radius: 50%;
  animation: pulse 2s ease-in-out infinite;
}

.hero h1 { margin-bottom: var(--sp-6); }
.hero p.lead { margin-bottom: var(--sp-8); max-width: 620px; margin-left: auto; margin-right: auto; }

.hero-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-4);
  flex-wrap: wrap;
}

.hero-scroll-hint {
  position: absolute;
  bottom: var(--sp-8);
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-2);
  color: var(--text-muted);
  font-size: 0.75rem;
  animation: float 2.5s ease-in-out infinite;
}

/* ─── Page Hero (non-home pages) ─── */
.page-hero {
  padding: calc(var(--nav-height) + var(--sp-16)) 0 var(--sp-16);
  text-align: center;
  background: radial-gradient(ellipse 70% 60% at 50% 0%, rgba(6,182,212,0.08) 0%, transparent 70%);
  border-bottom: 1px solid var(--border);
}

.page-hero h1 { margin-bottom: var(--sp-4); }
.page-hero p { max-width: 600px; margin: 0 auto; font-size: 1.05rem; }

/* ─── Two-column layout ─── */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-8);
  align-items: start;
}

.two-col-sticky { position: sticky; top: calc(var(--nav-height) + var(--sp-8)); }

/* ─── Highlight / glow divs ─── */
.glow-cyan   { box-shadow: 0 0 40px rgba(6,182,212,0.15); }
.glow-purple { box-shadow: 0 0 40px rgba(139,92,246,0.15); }

/* ─── Footer ─── */
footer {
  border-top: 1px solid var(--border);
  padding: var(--sp-12) 0 var(--sp-8);
  background: var(--bg-primary);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--sp-8);
  margin-bottom: var(--sp-10);
}

.footer-brand p { font-size: 0.85rem; margin-top: var(--sp-3); max-width: 260px; }

.footer-col h5 { color: var(--text-primary); margin-bottom: var(--sp-4); font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.1em; }

.footer-col ul { list-style: none; display: flex; flex-direction: column; gap: var(--sp-2); }

.footer-col a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.85rem;
  transition: color var(--transition-fast);
}

.footer-col a:hover { color: var(--cyan); }

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--sp-6);
  border-top: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ─── Scroll reveal ─── */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }
.reveal-delay-3 { transition-delay: 0.3s; }
.reveal-delay-4 { transition-delay: 0.4s; }

/* ─── Sidebar layout (how-it-works, math) ─── */
.sidebar-layout {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: var(--sp-8);
  align-items: start;
}

.sidebar-nav {
  position: sticky;
  top: calc(var(--nav-height) + var(--sp-6));
  background: var(--bg-glass);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: var(--sp-4);
  backdrop-filter: blur(10px);
}

.sidebar-nav-title {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--text-muted);
  font-weight: 600;
  padding: var(--sp-2) var(--sp-3);
  margin-bottom: var(--sp-2);
}

.sidebar-nav a {
  display: block;
  padding: var(--sp-2) var(--sp-3);
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.85rem;
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
  border-left: 2px solid transparent;
}

.sidebar-nav a:hover { color: var(--text-primary); background: rgba(255,255,255,0.04); }
.sidebar-nav a.active { color: var(--cyan); border-left-color: var(--cyan); background: rgba(6,182,212,0.06); }

/* ─── Concept sections (how-it-works) ─── */
.concept-section {
  scroll-margin-top: calc(var(--nav-height) + var(--sp-6));
  margin-bottom: var(--sp-16);
  padding-bottom: var(--sp-16);
  border-bottom: 1px solid var(--border);
}

.concept-section:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }

.concept-number {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--cyan);
  background: rgba(6,182,212,0.1);
  border: 1px solid rgba(6,182,212,0.2);
  padding: 2px 10px;
  border-radius: var(--radius-full);
  margin-bottom: var(--sp-3);
  display: inline-block;
}

.concept-section h3 { margin-bottom: var(--sp-4); }
.concept-section > p { margin-bottom: var(--sp-5); }

/* ─── Analogy box ─── */
.analogy-box {
  background: rgba(139,92,246,0.07);
  border: 1px solid rgba(139,92,246,0.2);
  border-radius: var(--radius-md);
  padding: var(--sp-4) var(--sp-5);
  margin: var(--sp-6) 0;
}

.analogy-label {
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--purple-light);
  margin-bottom: var(--sp-2);
}

.analogy-box p { font-size: 0.9rem; color: var(--text-primary); font-style: italic; margin: 0; }

/* ─── Math display ─── */
.math-box {
  background: #0d1117;
  border: 1px solid var(--border);
  border-left: 3px solid var(--cyan);
  border-radius: var(--radius-md);
  padding: var(--sp-5) var(--sp-6);
  margin: var(--sp-5) 0;
  overflow-x: auto;
}

.math-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: var(--sp-2);
}

/* ─── Matrix display ─── */
.matrix-display {
  display: inline-flex;
  align-items: stretch;
  gap: var(--sp-1);
}

.matrix-bracket {
  display: flex;
  align-items: center;
  font-size: 2rem;
  color: var(--cyan);
  font-weight: 200;
  font-family: var(--font-mono);
  line-height: 1;
}

.matrix-grid {
  display: grid;
  gap: var(--sp-2) var(--sp-5);
  padding: var(--sp-2) 0;
}

.matrix-cell {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text-code);
  text-align: right;
  min-width: 28px;
}

/* ─── Step indicator ─── */
.step-list { display: flex; flex-direction: column; gap: var(--sp-4); }

.step-item {
  display: flex;
  gap: var(--sp-4);
  align-items: flex-start;
}

.step-num {
  width: 32px; height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.8rem;
  font-weight: 700;
  flex-shrink: 0;
  border: 2px solid;
  font-family: var(--font-mono);
}

.step-num-cyan   { border-color: var(--cyan);         color: var(--cyan);         background: rgba(6,182,212,0.1); }
.step-num-purple { border-color: var(--purple);       color: var(--purple-light); background: rgba(139,92,246,0.1); }
.step-num-green  { border-color: var(--green);        color: var(--green);        background: rgba(16,185,129,0.1); }

.step-content h5 { margin-bottom: var(--sp-1); }
.step-content p  { font-size: 0.875rem; margin: 0; }

/* ─── Canvas wrapper ─── */
.canvas-wrap {
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border);
  background: #061020;
}

/* ─── Pulse / glow animations ─── */
@keyframes pulse {
  0%, 100% { opacity: 1; box-shadow: 0 0 0 0 rgba(6,182,212,0.4); }
  50% { opacity: 0.7; box-shadow: 0 0 0 6px rgba(6,182,212,0); }
}

@keyframes float {
  0%, 100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(8px); }
}

@keyframes shimmer {
  0% { background-position: -200% center; }
  100% { background-position: 200% center; }
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(12px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

@keyframes typing {
  from { width: 0; }
  to   { width: 100%; }
}

@keyframes blink {
  50% { border-color: transparent; }
}

.animate-in { animation: fadeIn 0.5s ease forwards; }

.spinner {
  width: 20px; height: 20px;
  border: 2px solid var(--border);
  border-top-color: var(--cyan);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

/* ─── Utilities ─── */
.flex         { display: flex; }
.flex-center  { display: flex; align-items: center; justify-content: center; }
.flex-between { display: flex; align-items: center; justify-content: space-between; }
.flex-col     { display: flex; flex-direction: column; }
.items-start  { align-items: flex-start; }
.gap-2        { gap: var(--sp-2); }
.gap-3        { gap: var(--sp-3); }
.gap-4        { gap: var(--sp-4); }
.gap-6        { gap: var(--sp-6); }
.gap-8        { gap: var(--sp-8); }

.text-center  { text-align: center; }
.text-left    { text-align: left; }

.mt-2 { margin-top: var(--sp-2); }
.mt-4 { margin-top: var(--sp-4); }
.mt-6 { margin-top: var(--sp-6); }
.mt-8 { margin-top: var(--sp-8); }
.mb-4 { margin-bottom: var(--sp-4); }
.mb-6 { margin-bottom: var(--sp-6); }
.mb-8 { margin-bottom: var(--sp-8); }
.mb-12 { margin-bottom: var(--sp-12); }

.w-full  { width: 100%; }
.hidden  { display: none; }
.block   { display: block; }
.relative { position: relative; }
.overflow-hidden { overflow: hidden; }

/* ─── Responsive ─── */
@media (max-width: 1024px) {
  .grid-4   { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .sidebar-layout { grid-template-columns: 1fr; }
  .sidebar-nav { position: static; }
}

@media (max-width: 768px) {
  .nav-links { display: none; }
  .nav-hamburger { display: flex; }

  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .two-col { grid-template-columns: 1fr; }
  .two-col-sticky { position: static; }

  .hero h1 { font-size: 2.2rem; }
  .hero-actions { flex-direction: column; align-items: stretch; }
  .hero-actions .btn { text-align: center; justify-content: center; }

  h2 { font-size: 1.8rem; }

  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: var(--sp-2); text-align: center; }

  .section { padding: var(--sp-16) 0; }
}

@media (max-width: 480px) {
  .container { padding: 0 var(--sp-4); }
  .card { padding: var(--sp-4); }
  .hero-content { padding: var(--sp-12) var(--sp-4); }
}