/* TankWise — clean, fast, mobile-first. No frameworks. */
:root {
  --bg: #f7fbfb;
  --card: #ffffff;
  --ink: #1d2b2e;
  --muted: #5a6f73;
  --accent: #0e7c86;
  --accent-dark: #0a5f66;
  --warn-bg: #fff8e6;
  --warn-border: #e0a92e;
  --danger-bg: #fdeeee;
  --danger-border: #c0392b;
  --ok-bg: #eef7ee;
  --ok-border: #3d8b4f;
  --line: #dfe9e9;
  --radius: 10px;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  color: var(--ink);
  background: var(--bg);
}
a { color: var(--accent-dark); }
a:hover { color: var(--accent); }

.site-header {
  background: var(--accent-dark);
  color: #fff;
  padding: 0.9rem 1rem;
}
.site-header .wrap {
  max-width: 760px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}
.brand { font-weight: 700; font-size: 1.25rem; color: #fff; text-decoration: none; }
.brand span { font-weight: 400; font-size: 0.9rem; opacity: 0.85; }
nav.main-nav ul { list-style: none; margin: 0; padding: 0; display: flex; gap: 1rem; flex-wrap: wrap; }
nav.main-nav a { color: #eaf6f6; text-decoration: none; font-size: 0.95rem; }
nav.main-nav a:hover { text-decoration: underline; }

.wrap { max-width: 760px; margin: 0 auto; padding: 0 1rem; }
main.wrap { padding-top: 1.25rem; padding-bottom: 2rem; }

.hero { margin: 0.5rem 0 1.5rem; }
.hero h1 { font-size: 1.7rem; line-height: 1.25; margin: 0 0 0.5rem; }
.hero p { color: var(--muted); margin: 0.25rem 0; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 1.25rem;
  margin: 1.25rem 0;
}
.card h2 { margin-top: 0; font-size: 1.35rem; }
.card h3 { font-size: 1.1rem; margin-bottom: 0.4rem; }

.field { margin: 0.7rem 0; }
.field label { display: block; font-weight: 600; margin-bottom: 0.25rem; }
.field .hint { font-size: 0.85rem; color: var(--muted); font-weight: 400; }
input[type="number"], select {
  width: 100%;
  max-width: 320px;
  padding: 0.6rem 0.7rem;
  font-size: 1rem;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--ink);
}
.unit-toggle { display: flex; gap: 0.5rem; margin: 0.5rem 0; }
.unit-toggle button {
  padding: 0.45rem 0.9rem;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 20px;
  cursor: pointer;
  font-size: 0.95rem;
}
.unit-toggle button[aria-pressed="true"] {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}
button.primary {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 0.7rem 1.4rem;
  font-size: 1rem;
  cursor: pointer;
  margin-top: 0.5rem;
}
button.primary:hover { background: var(--accent-dark); }

.result {
  margin-top: 1rem;
  padding: 1rem;
  border-radius: 8px;
  background: #f0f7f7;
  border: 1px solid var(--line);
}
.result .big { font-size: 1.6rem; font-weight: 700; color: var(--accent-dark); }
.result dl { margin: 0.5rem 0 0; display: grid; grid-template-columns: auto 1fr; gap: 0.2rem 0.8rem; }
.result dt { font-weight: 600; }
.result dd { margin: 0; }

.caveat {
  border-left: 4px solid var(--warn-border);
  background: var(--warn-bg);
  padding: 0.8rem 1rem;
  border-radius: 0 8px 8px 0;
  margin: 1rem 0;
  font-size: 0.95rem;
}
.caveat strong { display: block; margin-bottom: 0.25rem; }
.danger {
  border-left: 4px solid var(--danger-border);
  background: var(--danger-bg);
  padding: 0.8rem 1rem;
  border-radius: 0 8px 8px 0;
  margin: 1rem 0;
}
.ok-note {
  border-left: 4px solid var(--ok-border);
  background: var(--ok-bg);
  padding: 0.8rem 1rem;
  border-radius: 0 8px 8px 0;
  margin: 1rem 0;
}

.stock-table { width: 100%; border-collapse: collapse; margin-top: 0.5rem; }
.stock-table th, .stock-table td {
  text-align: left;
  padding: 0.55rem 0.4rem;
  border-bottom: 1px solid var(--line);
  font-size: 0.93rem;
  vertical-align: middle;
}
.stock-table th { font-size: 0.85rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.03em; }
.stepper { display: inline-flex; align-items: center; gap: 0.45rem; }
.stepper button {
  width: 2rem; height: 2rem;
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 6px;
  font-size: 1.1rem;
  cursor: pointer;
  line-height: 1;
}
.stepper button:hover { background: #eef4f4; }
.stepper .count { min-width: 1.6rem; text-align: center; font-weight: 700; }
.species-note { font-size: 0.82rem; color: var(--muted); display: block; }

.meter { height: 14px; background: #e3ecec; border-radius: 7px; overflow: hidden; margin: 0.6rem 0; }
.meter > div { height: 100%; background: var(--ok-border); transition: width 0.3s; }
.meter.warn > div { background: var(--warn-border); }
.meter.over > div { background: var(--danger-border); }

.faq details { border-bottom: 1px solid var(--line); padding: 0.7rem 0; }
.faq summary { font-weight: 600; cursor: pointer; }
.faq p { margin: 0.4rem 0 0; color: var(--muted); }

.guide-list { list-style: none; padding: 0; }
.guide-list li { margin: 0.6rem 0; }
.guide-list a { font-weight: 600; }

.affiliate-box {
  border: 1px dashed var(--line);
  border-radius: var(--radius);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  background: #fbfdfd;
}
.affiliate-box h2 { font-size: 1.1rem; margin-top: 0; }
.disclosure { font-size: 0.82rem; color: var(--muted); font-style: italic; }

article.guide h1 { font-size: 1.6rem; }
article.guide h2 { font-size: 1.25rem; margin-top: 1.6rem; }
article.guide table { width: 100%; border-collapse: collapse; margin: 0.8rem 0; font-size: 0.93rem; }
article.guide th, article.guide td { border: 1px solid var(--line); padding: 0.5rem; text-align: left; }
article.guide th { background: #eef4f4; }

.site-footer {
  border-top: 1px solid var(--line);
  margin-top: 2rem;
  padding: 1.5rem 1rem 2.5rem;
  font-size: 0.88rem;
  color: var(--muted);
}
.site-footer .wrap { max-width: 760px; }

@media (min-width: 600px) {
  .hero h1 { font-size: 2rem; }
  .two-col { display: grid; grid-template-columns: 1fr 1fr; gap: 0 1.5rem; }
}
@media (prefers-reduced-motion: reduce) {
  .meter > div { transition: none; }
}