/* === TOKENS === */
:root {
  --bg: #0a0d14;
  --bg-surface: #111520;
  --bg-card: #161c2c;
  --fg: #f0f2f8;
  --fg-muted: #8892a8;
  --accent: #f5a623;
  --accent-dim: #c47d0e;
  --border: #232a3c;
  --green: #4ade80;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

body {
  background: var(--bg);
  color: var(--fg);
  font-family: 'DM Sans', system-ui, sans-serif;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

::selection { background: var(--accent); color: var(--bg); }

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

/* === TYPOGRAPHY === */
h1, h2, h3, h4 { font-family: 'Fraunces', Georgia, serif; font-weight: 600; line-height: 1.2; }

/* === HEADER === */
.site-header {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(10, 13, 20, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.wordmark {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--accent);
  letter-spacing: -0.02em;
}
nav { display: flex; gap: 2rem; }
nav a {
  color: var(--fg-muted);
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  transition: color 0.2s;
}
nav a:hover { color: var(--fg); }

/* === HERO === */
.hero {
  padding: 8rem 2rem 5rem;
  background: linear-gradient(180deg, var(--bg) 0%, var(--bg-surface) 100%);
}
.hero-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}
.hero-eyebrow {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.5rem;
}
.hero-headline {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 600;
  line-height: 1.15;
  margin-bottom: 1.5rem;
  color: var(--fg);
}
.hero-sub {
  font-size: 1.0625rem;
  color: var(--fg-muted);
  line-height: 1.7;
  max-width: 440px;
}
.hero-stat {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 3rem;
  text-align: center;
}
.stat-number {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 5rem;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  margin-bottom: 0.5rem;
}
.stat-label {
  font-size: 1rem;
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 1rem;
}
.stat-note {
  font-size: 0.8125rem;
  color: var(--fg-muted);
  line-height: 1.5;
}

/* === MATH SECTION === */
.math { padding: 6rem 2rem; }
.math-inner { max-width: 1100px; margin: 0 auto; }
.section-title {
  font-size: clamp(1.75rem, 3vw, 2.5rem);
  margin-bottom: 3rem;
  color: var(--fg);
}
.math-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr auto 1fr;
  gap: 0;
  align-items: center;
  margin-bottom: 2.5rem;
}
.math-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 2rem 1.5rem;
  text-align: center;
}
.math-card--highlight { border-color: var(--accent); }
.math-card--result {
  background: linear-gradient(135deg, var(--bg-card), #1a2030);
  border-color: var(--green);
}
.card-step {
  font-size: 0.6875rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg-muted);
  margin-bottom: 1rem;
}
.card-number {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--fg);
  line-height: 1;
  margin-bottom: 0.5rem;
}
.math-card--highlight .card-number { color: var(--accent); }
.math-card--result .card-number { color: var(--green); }
.card-label {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--fg-muted);
  margin-bottom: 0.75rem;
}
.card-desc { font-size: 0.8125rem; color: var(--fg-muted); line-height: 1.5; }
.math-arrow { color: var(--fg-muted); display: flex; align-items: center; justify-content: center; }
.math-footnote {
  font-size: 0.875rem;
  color: var(--fg-muted);
  text-align: center;
  font-style: italic;
}

/* === HOW SECTION === */
.how { padding: 6rem 2rem; background: var(--bg-surface); }
.how-inner { max-width: 1100px; margin: 0 auto; }
.how-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 2px;
  background: var(--border);
  border-radius: 16px;
  overflow: hidden;
}
.how-item {
  background: var(--bg);
  padding: 3rem 2.5rem;
}
.how-number {
  font-family: 'Fraunces', Georgia, serif;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
}
.how-item h3 {
  font-size: 1.375rem;
  color: var(--fg);
  margin-bottom: 0.75rem;
}
.how-item p { font-size: 0.9375rem; color: var(--fg-muted); line-height: 1.7; }

/* === DIFFERENTIATOR === */
.diff { padding: 6rem 2rem; }
.diff-inner { max-width: 1100px; margin: 0 auto; }
.diff-quote {
  border-left: 3px solid var(--accent);
  padding-left: 2.5rem;
  margin-bottom: 4rem;
}
.diff-quote blockquote {
  font-family: 'Fraunces', Georgia, serif;
  font-size: clamp(1.5rem, 3vw, 2.25rem);
  font-weight: 300;
  font-style: italic;
  color: var(--fg);
  line-height: 1.3;
  margin-bottom: 1.5rem;
}
.diff-attribution { font-size: 1rem; color: var(--fg-muted); line-height: 1.7; }

/* === COMPOUND VISUAL === */
.diff-compound { background: var(--bg-card); border: 1px solid var(--border); border-radius: 16px; padding: 3rem; }
.compound-label {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--fg-muted);
  margin-bottom: 2rem;
}
.compound-visual { display: flex; flex-direction: column; gap: 1.25rem; margin-bottom: 1.5rem; }
.compound-bar {
  display: grid;
  grid-template-columns: 60px 1fr 100px;
  align-items: center;
  gap: 1rem;
}
.compound-year { font-size: 0.75rem; color: var(--fg-muted); font-weight: 500; }
.compound-fill {
  height: 36px;
  background: linear-gradient(90deg, var(--accent-dim), var(--accent));
  border-radius: 4px;
  width: var(--w, 33%);
  min-width: 40px;
  transition: width 0.6s ease;
}
.compound-val { font-size: 0.875rem; font-weight: 600; color: var(--accent); text-align: right; }
.compound-note { font-size: 0.8125rem; color: var(--fg-muted); line-height: 1.6; }

/* === CLOSING === */
.closing { padding: 8rem 2rem; background: linear-gradient(180deg, var(--bg-surface) 0%, var(--bg) 100%); }
.closing-inner { max-width: 700px; margin: 0 auto; text-align: center; }
.closing-headline {
  font-size: clamp(2rem, 4vw, 3rem);
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 1.5rem;
  line-height: 1.2;
}
.closing-sub { font-size: 1.0625rem; color: var(--fg-muted); line-height: 1.7; }

/* === FOOTER === */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 2rem;
}
.footer-inner {
  max-width: 1100px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.footer-brand .wordmark { font-size: 1rem; }
.footer-brand p { font-size: 0.75rem; color: var(--fg-muted); margin-top: 0.25rem; }
.footer-copy { font-size: 0.75rem; color: var(--fg-muted); }

/* === RESPONSIVE === */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 3rem; }
  .math-grid {
    grid-template-columns: 1fr;
    gap: 1rem;
  }
  .math-arrow { display: none; }
  .how-grid { grid-template-columns: 1fr; }
  .footer-inner { flex-direction: column; text-align: center; }
  .diff-quote { padding-left: 1.5rem; }
  nav { display: none; }
}

@media (max-width: 480px) {
  .hero { padding: 7rem 1.5rem 4rem; }
  .math, .how, .diff, .closing { padding: 4rem 1.5rem; }
  .compound-bar { grid-template-columns: 50px 1fr 80px; }
}