:root {
  --ink: #10261e;
  --ink-soft: #41564e;
  --brand: #0e7c66;
  --brand-deep: #0a5748;
  --water: #1673a7;
  --paper: #f5faf7;
  --card: #ffffff;
  --line: #dce8e2;
  --warn: #b4530a;
  --ok: #0f7b3f;
  --radius: 14px;
  --shadow: 0 6px 24px rgba(16, 38, 30, 0.07);
  --maxw: 1080px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--ink);
  background: var(--paper);
  line-height: 1.65;
}

a { color: var(--brand-deep); }

img { max-width: 100%; }

.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* Header */
.site-head {
  background: #ffffff;
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 40;
}
.head-in { display: flex; align-items: center; gap: 18px; min-height: 60px; }
.logo {
  font-weight: 800; font-size: 1.15rem; letter-spacing: -0.02em;
  color: var(--brand-deep); text-decoration: none; display: flex; align-items: center; gap: 8px;
}
.logo .dot {
  width: 14px; height: 14px; border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, #5ec8b4, var(--brand) 60%);
  display: inline-block;
}
.site-head nav { margin-left: auto; display: flex; gap: 4px; flex-wrap: wrap; }
.site-head nav a {
  text-decoration: none; color: var(--ink-soft); font-size: 0.92rem;
  padding: 8px 10px; border-radius: 8px;
}
.site-head nav a:hover { background: #eef6f2; color: var(--brand-deep); }

/* Hero */
.hero { padding: 56px 0 40px; }
.hero-grid { display: grid; grid-template-columns: 1.2fr 0.8fr; gap: 36px; align-items: center; }
h1 { font-size: clamp(1.7rem, 4vw, 2.6rem); line-height: 1.18; letter-spacing: -0.02em; margin: 0 0 16px; }
.hero p.lead { font-size: 1.08rem; color: var(--ink-soft); margin: 0 0 22px; }
.kicker {
  display: inline-block; background: #e3f2ec; color: var(--brand-deep);
  font-size: 0.8rem; font-weight: 700; padding: 4px 12px; border-radius: 999px; margin-bottom: 14px;
}
.btn {
  display: inline-block; background: var(--brand); color: #fff; text-decoration: none;
  padding: 12px 22px; border-radius: 10px; font-weight: 700; border: none; cursor: pointer;
  font-size: 1rem;
}
.btn:hover { background: var(--brand-deep); }
.btn.ghost { background: #fff; color: var(--brand-deep); border: 1.5px solid var(--brand); }
.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }

.hero-card {
  background: linear-gradient(160deg, #ffffff, #eef7f3);
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow);
}
.hero-card h2 { margin: 0 0 10px; font-size: 1.05rem; }
.gauge { display: flex; align-items: center; gap: 10px; margin: 8px 0; }
.gauge .bar { flex: 1; height: 10px; border-radius: 999px; background: #d8e6df; overflow: hidden; }
.gauge .bar span { display: block; height: 100%; width: 55%; background: linear-gradient(90deg, var(--ok), #d9a441 70%, #c0392b); }
.gauge b { min-width: 42px; text-align: right; }
.hero-card ul { margin: 12px 0 0; padding-left: 18px; color: var(--ink-soft); font-size: 0.93rem; }

/* Sections & cards */
section { padding: 34px 0; }
.sec-title { font-size: 1.5rem; letter-spacing: -0.01em; margin: 0 0 6px; }
.sec-sub { color: var(--ink-soft); margin: 0 0 24px; max-width: 720px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 18px; }
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }

.card {
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 22px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 8px;
}
.card h3 { margin: 0; font-size: 1.08rem; }
.card p { margin: 0; color: var(--ink-soft); font-size: 0.95rem; }
.card .more { margin-top: auto; font-weight: 700; font-size: 0.92rem; text-decoration: none; }
.icon {
  width: 40px; height: 40px; border-radius: 10px; display: flex; align-items: center;
  justify-content: center; font-size: 1.25rem; background: #e3f2ec;
}

/* Article layout */
.article { padding: 40px 0 20px; }
.article-grid { display: grid; grid-template-columns: minmax(0, 1fr) 300px; gap: 40px; }
.article h2 { font-size: 1.35rem; margin: 34px 0 10px; letter-spacing: -0.01em; }
.article h3 { font-size: 1.08rem; margin: 24px 0 8px; }
.article p { color: #22352e; }
.toc {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px 20px; box-shadow: var(--shadow); align-self: start; position: sticky; top: 80px;
}
.toc h4 { margin: 0 0 8px; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--ink-soft); }
.toc ol { margin: 0; padding-left: 18px; font-size: 0.92rem; }
.toc a { text-decoration: none; }
.meta { color: var(--ink-soft); font-size: 0.88rem; margin: 0 0 24px; }

/* Tables */
.tablewrap { overflow-x: auto; margin: 16px 0; }
table { border-collapse: collapse; width: 100%; background: #fff; font-size: 0.94rem; border-radius: 10px; overflow: hidden; }
th, td { text-align: left; padding: 10px 12px; border-bottom: 1px solid var(--line); vertical-align: top; }
th { background: #eef6f2; font-size: 0.85rem; text-transform: uppercase; letter-spacing: 0.04em; }
tr:last-child td { border-bottom: none; }

/* Callouts */
.note, .warn, .tip {
  border-left: 4px solid var(--brand); background: #eef7f3; border-radius: 0 10px 10px 0;
  padding: 14px 16px; margin: 18px 0; font-size: 0.96rem;
}
.warn { border-color: var(--warn); background: #fdf1e6; }
.tip { border-color: var(--water); background: #e9f4fa; }
.note b, .warn b, .tip b { display: block; margin-bottom: 4px; }

/* Product / affiliate cards */
.shop-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; margin: 20px 0; }
.shop {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 8px;
}
.shop .tag { font-size: 0.75rem; font-weight: 800; text-transform: uppercase; letter-spacing: 0.05em; color: var(--water); }
.shop h3 { margin: 0; font-size: 1rem; }
.shop p { margin: 0; font-size: 0.9rem; color: var(--ink-soft); }
.shop .btn { margin-top: auto; text-align: center; font-size: 0.92rem; }
.disclosure { font-size: 0.8rem; color: var(--ink-soft); margin-top: 10px; }

/* FAQ */
.faq { margin: 26px 0; }
.faq details {
  background: #fff; border: 1px solid var(--line); border-radius: 10px;
  padding: 14px 18px; margin-bottom: 10px;
}
.faq summary { cursor: pointer; font-weight: 700; }
.faq details[open] summary { color: var(--brand-deep); }

/* Calculators */
.calc {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 24px; margin: 24px 0;
}
.calc-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.field { display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 0.88rem; font-weight: 700; }
.field small { color: var(--ink-soft); }
.field input, .field select {
  padding: 10px 12px; border: 1.5px solid var(--line); border-radius: 9px; font-size: 1rem;
  background: #fbfdfc; color: var(--ink);
}
.field input:focus, .field select:focus { outline: 2px solid var(--brand); border-color: var(--brand); }
.result {
  margin-top: 22px; background: linear-gradient(150deg, #eef7f3, #ffffff);
  border: 1px solid var(--line); border-radius: 12px; padding: 20px;
}
.result .big { font-size: 2rem; font-weight: 800; color: var(--brand-deep); line-height: 1.1; }
.result .unit { font-size: 0.95rem; color: var(--ink-soft); font-weight: 600; }
.result ul { margin: 12px 0 0; padding-left: 20px; }
.bars { margin-top: 14px; display: flex; flex-direction: column; gap: 10px; }
.bar-row { display: grid; grid-template-columns: 170px 1fr 90px; gap: 10px; align-items: center; font-size: 0.9rem; }
.bar-track { background: #e2ece7; border-radius: 999px; height: 16px; overflow: hidden; }
.bar-fill { height: 100%; border-radius: 999px; background: var(--brand); }
.bar-fill.alt { background: var(--water); }
.bar-fill.warn { background: var(--warn); }
.bar-val { text-align: right; font-weight: 700; font-variant-numeric: tabular-nums; }

/* Steps */
.steps { counter-reset: step; list-style: none; padding: 0; margin: 18px 0; }
.steps li {
  counter-increment: step; position: relative; padding: 0 0 18px 52px;
}
.steps li::before {
  content: counter(step); position: absolute; left: 0; top: 0;
  width: 36px; height: 36px; border-radius: 50%; background: var(--brand);
  color: #fff; font-weight: 800; display: flex; align-items: center; justify-content: center;
}
.steps b { display: block; }

/* Footer */
.site-foot { background: #0b241d; color: #c9dcd4; margin-top: 40px; padding: 36px 0; font-size: 0.9rem; }
.site-foot a { color: #9fd3c3; }
.foot-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 28px; }
.site-foot h4 { color: #fff; margin: 0 0 10px; font-size: 0.95rem; }
.site-foot ul { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 6px; }
.site-foot p { margin: 0; }

.breadcrumb { font-size: 0.82rem; color: var(--ink-soft); padding: 14px 0 0; }
.breadcrumb a { text-decoration: none; }

@media (max-width: 900px) {
  .hero-grid, .article-grid { grid-template-columns: 1fr; }
  .grid-3, .shop-grid { grid-template-columns: 1fr 1fr; }
  .toc { position: static; }
  .foot-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 640px) {
  .grid-3, .grid-2, .calc-grid, .shop-grid, .foot-grid { grid-template-columns: 1fr; }
  .site-head nav { display: none; }
  .hero { padding: 36px 0 24px; }
  .bar-row { grid-template-columns: 1fr; gap: 4px; }
  .bar-val { text-align: left; }
}