/* Wearable Exercise Physiology Analytics — project site */
:root {
  --bg: #fbfaf7;
  --surface: #ffffff;
  --surface-2: #f3f1ec;
  --ink: #15140f;
  --ink-2: #4a4843;
  --ink-3: #7a776f;
  --rule: #e5e2da;
  --accent: #1f6feb;
  --aerobic: #2a78d6;
  --anaerobic: #eb6834;
  --stress: #1baf7a;
  --warn: #b7791f;
  --radius: 14px;
  --shadow: 0 1px 2px rgba(20, 18, 10, .04), 0 8px 24px rgba(20, 18, 10, .06);
  --maxw: 1120px;
  --font: "Inter", system-ui, -apple-system, "Segoe UI", sans-serif;
  --serif: "Source Serif 4", Georgia, serif;
  --mono: "JetBrains Mono", ui-monospace, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #12120f; --surface: #1a1a17; --surface-2: #22221e; --ink: #f4f2ec; --ink-2: #c9c6bc;
    --ink-3: #9a978d; --rule: #2e2d28; --accent: #5b9bff; --aerobic: #3987e5; --anaerobic: #e46a3a;
    --stress: #22b783; --shadow: 0 1px 2px rgba(0,0,0,.3), 0 8px 24px rgba(0,0,0,.35); color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #12120f; --surface: #1a1a17; --surface-2: #22221e; --ink: #f4f2ec; --ink-2: #c9c6bc;
  --ink-3: #9a978d; --rule: #2e2d28; --accent: #5b9bff; --aerobic: #3987e5; --anaerobic: #e46a3a;
  --stress: #22b783; --shadow: 0 1px 2px rgba(0,0,0,.3), 0 8px 24px rgba(0,0,0,.35); color-scheme: dark;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 16px/1.65 var(--font); -webkit-font-smoothing: antialiased; }
img { max-width: 100%; display: block; }
a { color: var(--accent); text-underline-offset: 3px; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 16px; }
@media (min-width: 720px) { .wrap { padding: 0 32px; } }

/* nav */
.nav { position: sticky; top: 0; z-index: 10; backdrop-filter: saturate(1.4) blur(10px);
  background: color-mix(in srgb, var(--bg) 82%, transparent); border-bottom: 1px solid var(--rule); }
.nav .wrap { display: flex; align-items: center; gap: 20px; height: 58px; }
.brand { font-weight: 700; letter-spacing: -.01em; color: var(--ink); text-decoration: none; white-space: nowrap; }
.brand span { color: var(--ink-3); font-weight: 500; }
.nav ul { display: none; list-style: none; margin: 0 0 0 auto; padding: 0; gap: 22px; }
.nav ul a { color: var(--ink-2); text-decoration: none; font-size: 14px; }
.nav ul a:hover { color: var(--ink); }
@media (min-width: 900px) { .nav ul { display: flex; } }
.theme-btn { margin-left: auto; border: 1px solid var(--rule); background: var(--surface); color: var(--ink-2);
  border-radius: 999px; padding: 6px 12px; font: 13px var(--font); cursor: pointer; }
@media (min-width: 900px) { .theme-btn { margin-left: 0; } }

/* hero */
.hero { padding: 72px 0 40px; }
.eyebrow { text-transform: uppercase; letter-spacing: .14em; font-size: 12px; font-weight: 600; color: var(--ink-3); }
.hero h1 { font-family: var(--serif); font-weight: 600; font-size: clamp(34px, 5.4vw, 60px); line-height: 1.06;
  letter-spacing: -.02em; margin: 14px 0 18px; max-width: 18ch; }
.hero .lede { font-size: clamp(17px, 2vw, 20px); color: var(--ink-2); max-width: 62ch; }
.chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 22px; }
.chip { display: inline-flex; align-items: center; gap: 8px; border: 1px solid var(--rule); background: var(--surface);
  border-radius: 999px; padding: 6px 12px; font-size: 13px; color: var(--ink-2); }
.dot { width: 9px; height: 9px; border-radius: 50%; display: inline-block; }
.dot.aer { background: var(--aerobic); } .dot.ana { background: var(--anaerobic); } .dot.str { background: var(--stress); }
.cta { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 28px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 11px 18px; border-radius: 10px; font-weight: 600;
  font-size: 15px; text-decoration: none; border: 1px solid var(--rule); color: var(--ink); background: var(--surface); }
.btn.primary { background: var(--ink); color: var(--bg); border-color: var(--ink); }
.btn:hover { transform: translateY(-1px); }

/* stats strip */
.stats { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1px; background: var(--rule); border: 1px solid var(--rule);
  border-radius: var(--radius); overflow: hidden; margin: 36px 0 8px; }
@media (min-width: 820px) { .stats { grid-template-columns: repeat(4, 1fr); } }
.stat { background: var(--surface); padding: 20px 22px; }
.stat b { display: block; font-family: var(--serif); font-size: 34px; line-height: 1.1; font-weight: 600; }
.stat span { color: var(--ink-3); font-size: 14px; }

/* sections */
section { padding: 56px 0; border-top: 1px solid var(--rule); }
section h2 { font-family: var(--serif); font-weight: 600; font-size: clamp(26px, 3.4vw, 38px); letter-spacing: -.015em;
  line-height: 1.15; margin: 8px 0 14px; max-width: 26ch; }
section .intro { color: var(--ink-2); max-width: 68ch; font-size: 17px; }
h3 { font-size: 18px; margin: 0 0 6px; letter-spacing: -.005em; }
.grid-2 { display: grid; gap: 22px; grid-template-columns: 1fr; margin-top: 26px; }
.grid-3 { display: grid; gap: 18px; grid-template-columns: 1fr; margin-top: 26px; }
@media (min-width: 820px) { .grid-2 { grid-template-columns: 1fr 1fr; } .grid-3 { grid-template-columns: repeat(3, 1fr); } }
.card { background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius); padding: 22px; box-shadow: var(--shadow); }
.card p { margin: 6px 0 0; color: var(--ink-2); font-size: 15px; }
.card .num { font-family: var(--serif); font-size: 28px; font-weight: 600; }
.card.finding { border-left: 4px solid var(--accent); }
.card.finding.str { border-left-color: var(--stress); } .card.finding.aer { border-left-color: var(--aerobic); }
.card.finding.ana { border-left-color: var(--anaerobic); } .card.finding.warn { border-left-color: var(--warn); }

figure { margin: 28px 0 0; background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius);
  padding: 14px; box-shadow: var(--shadow); }
figure img { border-radius: 8px; width: 100%; height: auto; background: #fff; }
figcaption { color: var(--ink-3); font-size: 14px; margin-top: 10px; padding: 0 4px; }
figcaption b { color: var(--ink-2); }

.callout { margin-top: 26px; padding: 18px 20px; border-radius: var(--radius); background: var(--surface-2);
  border: 1px solid var(--rule); color: var(--ink-2); }
.callout b { color: var(--ink); }

table { width: 100%; border-collapse: collapse; font-size: 14.5px; margin-top: 18px; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--rule); vertical-align: top; }
th { color: var(--ink-3); font-weight: 600; font-size: 12.5px; text-transform: uppercase; letter-spacing: .06em; }
td.n { font-variant-numeric: tabular-nums; text-align: right; white-space: nowrap; }
.table-wrap { overflow-x: auto; background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius); padding: 4px 8px; margin-top: 22px; }

.steps { counter-reset: s; list-style: none; padding: 0; margin: 24px 0 0; display: grid; gap: 14px; }
.steps li { counter-increment: s; background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius);
  padding: 16px 18px 16px 62px; position: relative; color: var(--ink-2); }
.steps li::before { content: counter(s); position: absolute; left: 18px; top: 15px; width: 30px; height: 30px; border-radius: 50%;
  background: var(--ink); color: var(--bg); display: grid; place-items: center; font-weight: 700; font-size: 14px; }
.steps li b { color: var(--ink); }

.bar { height: 10px; border-radius: 6px; background: var(--surface-2); overflow: hidden; margin-top: 6px; }
.bar i { display: block; height: 100%; background: var(--accent); border-radius: 6px; }

footer { padding: 40px 0 60px; color: var(--ink-3); font-size: 14px; border-top: 1px solid var(--rule); }
footer a { color: var(--ink-2); }
code { font-family: var(--mono); font-size: .9em; background: var(--surface-2); padding: 1px 6px; border-radius: 6px; }
.muted { color: var(--ink-3); }
.tag { font-size: 12px; font-weight: 600; padding: 2px 8px; border-radius: 999px; background: var(--surface-2); color: var(--ink-2); }