/* ═══════════════════════════════════════════════════════════════
   MODERN DARK THEME — Cool-toned, no gold/yellow
   ═══════════════════════════════════════════════════════════════ */

:root {
  /* Backgrounds */
  --bg-obsidian:  #06080D;
  --bg-panel:     #0F1318;
  --bg-charcoal:  #0A0D12;
  --bg-surface:   #151A22;

  /* Borders & grid */
  --grid:         #2A3040;
  --grid-15:      rgba(42, 48, 64, 0.25);

  /* Text */
  --text-primary:   #F0F2F5;
  --text-secondary: #8B95A5;
  --text-dim:       #505A6A;

  /* Accent — electric blue spectrum */
  --accent:       #3B82F6;
  --accent-light: #60A5FA;
  --accent-glow:  #2563EB;
  --accent-hover: #93C5FD;

  /* Signal colors */
  --cyan:         #06B6D4;
  --teal:         #14B8A6;
  --emerald:      #10B981;
  --red:          #EF4444;
  --orange:       #F97316;
  --violet:       #8B5CF6;
  --rose:         #EC4899;
  --sky:          #38BDF8;
  --ice:          #A5F3FC;

  /* Markov state colors */
  --state-current:     #10B981;
  --state-early-dq:    #38BDF8;
  --state-mid-dq:      #F97316;
  --state-late-dq:     #EF4444;
  --state-severe:      #DC2626;
  --state-paid-down:   #06B6D4;
  --state-charged-off: #EF4444;

  /* Typography */
  --font-mono:    'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
  --font-display: 'Inter', 'SF Pro Display', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  /* Spacing */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 2rem;
  --space-xl: 4rem;
  --space-2xl: 6rem;

  /* Borders */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;

  /* Transitions */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

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

html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-mono);
  font-size: 15px;
  line-height: 1.6;
  color: var(--text-primary);
  background: var(--bg-obsidian);
  overflow-x: hidden;
}

a {
  color: var(--accent-light);
  text-decoration: none;
  transition: color 0.2s var(--ease-out);
}
a:hover { color: var(--accent-hover); }

img { max-width: 100%; height: auto; display: block; }

h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 700; line-height: 1.2; }

/* ─── UTILITY ─── */
.sr-only {
  position: absolute; width: 1px; height: 1px;
  padding: 0; margin: -1px; overflow: hidden;
  clip: rect(0,0,0,0); border: 0;
}

/* ─── BUTTONS ─── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 2rem;
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  cursor: pointer;
  transition: all 0.25s var(--ease-out);
  text-decoration: none;
  border: none;
}

.btn--outline {
  border: 1.5px solid var(--accent);
  color: var(--accent-light);
  background: transparent;
}
.btn--outline:hover {
  background: rgba(59, 130, 246, 0.1);
  color: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 20px rgba(59, 130, 246, 0.15);
}

.btn--solid {
  background: linear-gradient(135deg, var(--accent) 0%, var(--accent-glow) 100%);
  color: #fff;
}
.btn--solid:hover {
  background: linear-gradient(135deg, var(--accent-light) 0%, var(--accent) 100%);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 8px 30px rgba(59, 130, 246, 0.3);
}

.btn--full { width: 100%; }

/* ─── SCROLL REVEAL ─── */
.reveal {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.6s var(--ease-out), transform 0.6s var(--ease-out);
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}