:root {
  --bg:           #0F0F0E;
  --bg-card:      #161615;
  --bg-raised:    #1C1C1A;
  --border:       #2C2C2A;
  --border-mid:   #444441;
  --text-primary:   #F1EFE8;
  --text-secondary: #888780;
  --text-tertiary:  #5F5E5A;
  --accent:         #662af2;
  --fever:    #E24B4A;
  --recovery: #1D9E75;
  --warning:  #D85A30;
  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --max-width: 860px;
  --section-gap: 120px;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  background: var(--bg);
  color: var(--text-primary);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container { max-width: var(--max-width); margin: 0 auto; padding: 0 28px; }

/* Nav */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 16px 28px;
  display: flex; justify-content: space-between; align-items: center;
  background: rgba(15,15,14,0.85);
  backdrop-filter: blur(12px);
  border-bottom: 0.5px solid var(--border);
}
.nav-logo { font-size: 15px; font-weight: 500; color: var(--text-primary); text-decoration: none; }
.nav-logo span { color: var(--accent); }
.nav-links { display: flex; gap: 24px; list-style: none; }
.nav-links a { font-size: 13px; color: var(--text-tertiary); text-decoration: none; transition: color .15s; }
.nav-links a:hover { color: var(--text-primary); }
.nav-github { font-size: 13px; color: var(--text-tertiary); text-decoration: none; transition: color .15s; }
.nav-github:hover { color: var(--text-primary); }
@media (max-width: 680px) { .nav-links { display: none; } }

/* Sections */
section { padding: var(--section-gap) 0; border-top: 0.5px solid var(--border); }
.hero { border-top: none; padding-top: 140px; padding-bottom: 80px; min-height: 100vh; }

/* Typography */
.eyebrow { font-size: 11px; font-weight: 500; letter-spacing: .1em; text-transform: uppercase; color: var(--text-tertiary); margin-bottom: 16px; }
h1 { font-size: clamp(40px, 7vw, 72px); font-weight: 500; letter-spacing: -.035em; line-height: 1.05; margin-bottom: 20px; }
h2 { font-size: clamp(28px, 4vw, 44px); font-weight: 500; letter-spacing: -.025em; line-height: 1.15; margin-bottom: 24px; }
h3 { font-size: 18px; font-weight: 500; color: var(--text-primary); margin-bottom: 10px; }
p { color: var(--text-secondary); line-height: 1.75; max-width: 600px; }
p + p { margin-top: 14px; }
strong { color: var(--text-primary); font-weight: 500; }
.accent { color: var(--accent); }

/* Hero */
.hero-tag { display: inline-block; font-size: 11px; padding: 5px 14px; border-radius: 20px; border: 0.5px solid var(--border-mid); color: var(--text-tertiary); margin-bottom: 28px; }
.hero-sub { font-size: 18px; color: var(--text-secondary); line-height: 1.65; max-width: 520px; margin-bottom: 48px; }
.hero-stats { display: flex; gap: 48px; flex-wrap: wrap; margin-bottom: 64px; }
.hero-stat-val { font-size: 30px; font-weight: 500; color: var(--text-primary); letter-spacing: -.02em; }
.hero-stat-label { font-size: 12px; color: var(--text-tertiary); margin-top: 3px; }

/* Fever artifact */
.fever-artifact {
  background: #0A0A09;
  border: 0.5px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  margin-top: 16px;
}
.fa-kicker { font-size: 10px; font-weight: 500; letter-spacing: .12em; text-transform: uppercase; color: var(--text-tertiary); padding: 24px 28px 0; }
.fa-hero-row { display: flex; justify-content: space-between; align-items: flex-end; padding: 14px 28px 20px; border-bottom: 0.5px solid var(--border); gap: 24px; }
.fa-hed { font-size: clamp(22px, 3vw, 30px); font-weight: 500; color: var(--text-primary); letter-spacing: -.02em; line-height: 1.2; }
.fa-hed span { color: var(--text-tertiary); }
.fa-sub { font-size: 13px; color: var(--text-tertiary); margin-top: 8px; line-height: 1.6; max-width: 340px; }
.fa-right { text-align: right; flex-shrink: 0; }
.fa-big-num { font-size: 52px; font-weight: 500; color: var(--fever); letter-spacing: -.04em; line-height: 1; }
.fa-big-label { font-size: 10px; color: #712B13; margin-top: 4px; letter-spacing: .06em; text-transform: uppercase; }
.fa-strip-label { font-size: 9px; color: var(--text-tertiary); letter-spacing: .08em; text-transform: uppercase; padding: 18px 28px 8px; }
.fa-strip { display: flex; gap: 3px; align-items: flex-end; height: 44px; padding: 0 28px; }
.fa-bar { flex: 1; border-radius: 2px 2px 0 0; }
.fa-strip-dates { display: flex; justify-content: space-between; font-size: 9px; color: var(--text-tertiary); padding: 6px 28px 16px; border-bottom: 0.5px solid var(--border); }
.fa-strip-dates .peak { color: var(--fever); font-weight: 500; }
.fa-body { display: grid; grid-template-columns: 1fr 1fr; gap: 0; }
@media (max-width: 600px) { .fa-body { grid-template-columns: 1fr; } }
.fa-stats { padding: 20px 28px; border-right: 0.5px solid var(--border); display: grid; grid-template-columns: 1fr 1fr; gap: 12px; align-content: start; }
.fa-stat { background: var(--bg-card); border-radius: 8px; padding: 10px 12px; }
.fa-stat-val { font-size: 22px; font-weight: 500; color: var(--text-primary); }
.fa-stat-val.red { color: var(--fever); }
.fa-stat-name { font-size: 9px; letter-spacing: .06em; text-transform: uppercase; color: var(--text-tertiary); margin-top: 3px; }
.fa-stat-delta { font-size: 10px; color: #712B13; margin-top: 2px; }
.fa-timeline { padding: 20px 24px; }
.fa-tl-label { font-size: 9px; letter-spacing: .1em; text-transform: uppercase; color: var(--text-tertiary); margin-bottom: 12px; }
.fa-event { display: flex; gap: 8px; padding: 8px 0; border-bottom: 0.5px solid var(--border); align-items: flex-start; font-size: 12px; color: var(--text-secondary); }
.fa-event:last-child { border-bottom: none; }
.fa-event.highlight { background: rgba(226,75,74,0.05); margin: 0 -8px; padding: 8px 8px; border-radius: 6px; }
.fa-date { font-size: 10px; color: var(--text-tertiary); width: 34px; flex-shrink: 0; padding-top: 2px; }
.fa-date.red { color: var(--fever); }
.fa-dot { width: 8px; height: 8px; border-radius: 50%; flex-shrink: 0; margin-top: 4px; }
.fa-event strong { display: block; color: var(--text-primary); font-weight: 500; font-size: 12px; }
.fa-footer { padding: 16px 28px; background: #0A0A09; display: flex; justify-content: space-between; align-items: center; gap: 16px; flex-wrap: wrap; border-top: 0.5px solid var(--border); }
.fa-insight { font-size: 12px; color: var(--text-tertiary); max-width: 440px; line-height: 1.6; }
.fa-tag { font-size: 10px; color: var(--border-mid); letter-spacing: .08em; text-transform: uppercase; }

/* Two col */
.two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 48px; margin-top: 32px; }
@media (max-width: 640px) { .two-col { grid-template-columns: 1fr; gap: 24px; } }

/* Framework */
.framework { margin-top: 64px; }
.fw-label { font-size: 11px; font-weight: 500; letter-spacing: .1em; text-transform: uppercase; color: var(--text-tertiary); margin-bottom: 20px; }
.fw-layers { }
.fw-layer { border-radius: 14px; padding: 20px; border: 0.5px solid; }
.fw-outer { border-color: #185FA5; background: rgba(24,95,165,0.04); }
.fw-mid { border-color: #1D9E75; background: rgba(29,158,117,0.04); margin-top: 16px; }
.fw-core { border-color: #BA7517; background: rgba(186,117,23,0.04); margin-top: 16px; }
.fw-inner { }
.fw-layer-title { font-size: 14px; font-weight: 500; color: var(--text-primary); margin-bottom: 3px; }
.fw-layer-sub { font-size: 11px; color: var(--text-tertiary); margin-bottom: 10px; }
.fw-layer-knows { font-size: 11px; color: var(--text-secondary); }
.fw-layer-cant { font-size: 11px; color: #993C1D; margin-top: 3px; }
.fw-center { background: var(--bg-card); border-radius: 10px; padding: 14px 16px; margin-top: 16px; text-align: center; }
.fw-center-title { font-size: 14px; font-weight: 500; color: var(--text-primary); }
.fw-center-sub { font-size: 11px; color: var(--text-tertiary); margin-top: 3px; }

/* Findings */
.finding { margin-top: 56px; padding-top: 56px; border-top: 0.5px solid var(--border); }
.finding:first-of-type { border-top: none; padding-top: 32px; margin-top: 32px; }
.finding-tag { display: inline-block; font-size: 11px; font-weight: 500; padding: 4px 12px; border-radius: 6px; margin-bottom: 12px; letter-spacing: .04em; }
.finding p { margin-top: 12px; }

/* HRV table */
.hrv-table { margin-top: 24px; border: 0.5px solid var(--border); border-radius: 10px; overflow: hidden; font-size: 13px; }
.hrv-row { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr 1fr; padding: 10px 16px; border-bottom: 0.5px solid var(--border); }
.hrv-row:last-child { border-bottom: none; }
.hrv-row.header { color: var(--text-tertiary); font-size: 11px; letter-spacing: .06em; text-transform: uppercase; background: var(--bg-raised); }
.hrv-row.best { background: rgba(29,158,117,0.06); }
.hrv-row.bad { background: rgba(216,90,48,0.06); }
.highlight-cell { color: var(--recovery); font-weight: 500; }
.neg { color: var(--warning); }

/* VO2 chart */
.vo2-chart-wrap { margin-top: 32px; position: relative; height: 200px; }

/* Predictions */
.predictions-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; margin-top: 40px; }
.pred-card { background: var(--bg-card); border-radius: 12px; padding: 20px; border-left: 2px solid; border-radius: 0 12px 12px 0; }
.pred-card.improve { border-left-color: var(--recovery); }
.pred-card.worsen  { border-left-color: var(--warning); }
.pred-card.stable  { border-left-color: var(--text-tertiary); }
.pred-card.unknown { border-left-color: var(--accent); }
.pred-direction { font-size: 10px; font-weight: 500; letter-spacing: .08em; text-transform: uppercase; color: var(--text-tertiary); margin-bottom: 8px; }
.pred-card.improve .pred-direction { color: var(--recovery); }
.pred-card.worsen  .pred-direction { color: var(--warning); }
.pred-card.unknown .pred-direction { color: var(--accent); }
.pred-name { font-size: 15px; font-weight: 500; color: var(--text-primary); margin-bottom: 6px; }
.pred-baseline { font-size: 11px; color: var(--text-tertiary); margin-bottom: 10px; }
.pred-reason { font-size: 12px; color: var(--text-secondary); line-height: 1.6; }

/* System */
.system-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 12px; margin-top: 40px; }
.sys-card { background: var(--bg-card); border-radius: 12px; padding: 24px; }
.sys-num { font-size: 11px; font-weight: 500; letter-spacing: .1em; color: var(--accent); margin-bottom: 12px; }
.sys-card h3 { margin-bottom: 10px; }
.sys-card p { font-size: 13px; max-width: none; }
.tech-stack { margin-top: 48px; }
.tech-label { font-size: 11px; font-weight: 500; letter-spacing: .1em; text-transform: uppercase; color: var(--text-tertiary); margin-bottom: 14px; }
.tech-chips { display: flex; flex-wrap: wrap; gap: 8px; }
.tech-chips span { font-size: 12px; padding: 5px 14px; border-radius: 20px; border: 0.5px solid var(--border-mid); color: var(--text-secondary); }

/* Reflection */
.next-question { margin-top: 56px; background: var(--bg-card); border-radius: 12px; padding: 28px; border-left: 2px solid var(--accent); border-radius: 0 12px 12px 0; }
.nq-label { font-size: 10px; font-weight: 500; letter-spacing: .1em; text-transform: uppercase; color: var(--accent); opacity: .8; margin-bottom: 10px; }
.nq-text { font-size: 15px; color: var(--text-secondary); line-height: 1.75; max-width: 580px; }
.closing { margin-top: 72px; padding-top: 40px; border-top: 0.5px solid var(--border); }
.closing p { font-size: 20px; color: var(--text-secondary); line-height: 1.65; max-width: 540px; margin-bottom: 32px; }
.closing-links { display: flex; gap: 24px; }
.closing-links a { font-size: 14px; color: var(--text-tertiary); text-decoration: none; border-bottom: 0.5px solid var(--border-mid); padding-bottom: 2px; transition: all .15s; }
.closing-links a:hover { color: var(--text-primary); border-color: var(--text-primary); }

/* Footer */
footer { padding: 32px 0; border-top: 0.5px solid var(--border); }
footer .container { display: flex; justify-content: space-between; align-items: center; font-size: 12px; color: var(--text-tertiary); }

/* Fade in */
.fade-in { opacity: 0; transform: translateY(24px); transition: opacity .7s ease, transform .7s ease; }
.fade-in.visible { opacity: 1; transform: translateY(0); }