:root {
  --bg: #f7f6f3;
  --card: #ffffff;
  --ink: #1d1d1f;
  --muted: #5d5d61;
  --accent: #b23b1e;
  --accent-soft: #fbe9e2;
  --line: #e4e1da;
  --ok: #1e7b3c;
  --warn: #a05a00;
  --radius: 12px;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.55;
  font-size: 17px;
}

.wrap { max-width: 760px; margin: 0 auto; padding: 0 16px 64px; }

header.site {
  border-bottom: 1px solid var(--line);
  padding: 18px 16px;
  max-width: 760px; margin: 0 auto;
}
header.site .brand { font-weight: 800; font-size: 1.25rem; text-decoration: none; color: var(--ink); }
nav.site-nav { display: flex; gap: 14px; margin-top: 8px; flex-wrap: wrap; }
nav.site-nav a { color: var(--accent); text-decoration: none; font-weight: 600; font-size: 0.95rem; }
nav.site-nav a:hover { text-decoration: underline; }

h1 { font-size: 1.9rem; line-height: 1.2; margin: 1.6rem 0 0.5rem; }
h2 { font-size: 1.35rem; margin: 2.2rem 0 0.6rem; }
h3 { font-size: 1.1rem; margin: 1.6rem 0 0.4rem; }
p.lede { color: var(--muted); font-size: 1.05rem; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px;
  margin: 1.2rem 0;
  box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}

.safety {
  border: 2px solid var(--accent);
  background: var(--accent-soft);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin: 1.2rem 0;
}
.safety strong { display: block; margin-bottom: 4px; }

.field { margin: 0.9rem 0; }
.field label { display: block; font-weight: 600; margin-bottom: 4px; }
.field .hint { font-size: 0.85rem; color: var(--muted); margin-top: 3px; }
input[type="number"], select {
  width: 100%;
  max-width: 340px;
  padding: 10px 12px;
  font-size: 1rem;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--ink);
}
.unit-toggle { display: flex; gap: 8px; margin: 0.4rem 0; }
.unit-toggle button {
  padding: 8px 16px; border: 1px solid var(--line); border-radius: 8px;
  background: #fff; cursor: pointer; font-size: 0.95rem; font-weight: 600;
}
.unit-toggle button[aria-pressed="true"] { background: var(--ink); color: #fff; border-color: var(--ink); }

button.calc-btn {
  background: var(--accent); color: #fff; border: none; border-radius: 8px;
  padding: 12px 24px; font-size: 1.05rem; font-weight: 700; cursor: pointer; margin-top: 0.6rem;
}
button.calc-btn:hover { filter: brightness(1.08); }

.result {
  border-left: 4px solid var(--ok);
  background: #f2faf5;
  padding: 14px 18px;
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 1rem 0;
}
.result .big { font-size: 1.6rem; font-weight: 800; }
.result .sub { color: var(--muted); font-size: 0.95rem; }

table.chart { width: 100%; border-collapse: collapse; margin: 0.8rem 0; font-size: 0.95rem; }
table.chart th, table.chart td { border: 1px solid var(--line); padding: 8px 10px; text-align: left; }
table.chart th { background: #f0eee9; }
table.chart tr.me { background: #fff6d8; }

.note { font-size: 0.9rem; color: var(--muted); }
.formula {
  font-family: ui-monospace, monospace; font-size: 0.88rem;
  background: #f0eee9; padding: 8px 12px; border-radius: 6px; display: inline-block;
}
ol.steps li, ul.tips li { margin-bottom: 0.5rem; }

details { border: 1px solid var(--line); border-radius: 8px; margin: 0.5rem 0; background: #fff; }
details summary { padding: 12px 16px; cursor: pointer; font-weight: 600; }
details .body { padding: 0 16px 14px; }

.affiliate-box {
  border: 1px dashed var(--line); border-radius: var(--radius);
  padding: 16px 20px; margin: 1.5rem 0; color: var(--muted); font-size: 0.9rem;
}
.affiliate-box a { color: var(--accent); pointer-events: none; text-decoration: none; border-bottom: 1px dotted; }
.disclosure { font-size: 0.8rem; color: var(--muted); }

footer.site {
  border-top: 1px solid var(--line); margin-top: 3rem; padding: 1.5rem 16px 3rem;
  max-width: 760px; margin-left: auto; margin-right: auto; color: var(--muted); font-size: 0.85rem;
}

@media (max-width: 480px) {
  h1 { font-size: 1.55rem; }
  body { font-size: 16px; }
}