/* TankWise — hand-built stylesheet. No frameworks, no external fonts. */
:root{
  --ink:#0d2b33; --ink-soft:#3d5a63; --bg:#f4f9fa; --card:#ffffff;
  --teal:#0b7285; --teal-dark:#085a6a; --aqua:#e3f2f5; --line:#d5e6ea;
  --amber:#e8912d; --good:#1d8a4e; --warn:#b7791f; --bad:#c92a2a;
  --radius:14px; --maxw:1060px;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;
  color:var(--ink);background:var(--bg);line-height:1.65;font-size:17px}
a{color:var(--teal);text-decoration-thickness:1px;text-underline-offset:2px}
a:hover{color:var(--teal-dark)}
:focus-visible{outline:3px solid var(--amber);outline-offset:2px;border-radius:4px}
.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px}
.skip{position:absolute;left:-9999px;top:0;background:var(--ink);color:#fff;padding:10px 16px;z-index:50}
.skip:focus{left:8px;top:8px}
/* Header */
header.site{background:var(--ink);color:#fff}
.navbar{display:flex;align-items:center;gap:18px;padding:14px 0;flex-wrap:wrap}
.logo{color:#fff;text-decoration:none;font-weight:800;font-size:1.35rem;letter-spacing:.2px}
.logo span{color:#7fd1de}
.tagline{color:#b9d8de;font-size:.85rem;display:block;font-weight:400;margin-top:-4px}
nav.main{margin-left:auto}
nav.main ul{display:flex;gap:4px;list-style:none;margin:0;padding:0;flex-wrap:wrap}
nav.main a{color:#eaf6f8;text-decoration:none;padding:8px 12px;border-radius:8px;font-size:.98rem}
nav.main a:hover,nav.main a[aria-current]{background:#16414d;color:#fff}
/* Hero */
.hero{background:linear-gradient(150deg,#0b7285,#085a6a 60%,#0d2b33);color:#fff;padding:52px 0 46px}
.hero h1{font-size:2.3rem;line-height:1.2;margin:0 0 12px}
.hero p{max-width:640px;color:#d9eff3;font-size:1.08rem;margin:0 0 22px}
.btn{display:inline-block;background:var(--amber);color:#231600;font-weight:700;text-decoration:none;
  padding:13px 24px;border-radius:10px;border:0;cursor:pointer;font-size:1rem}
.btn:hover{background:#d17f1d;color:#231600}
.btn.secondary{background:#fff;color:var(--teal-dark);border:2px solid var(--teal)}
.btn.secondary:hover{background:var(--aqua)}
/* Layout */
main{padding:34px 0 10px}
h1{font-size:2rem;line-height:1.25;margin:.2em 0 .5em}
h2{font-size:1.45rem;margin:1.5em 0 .5em;line-height:1.3}
h3{font-size:1.15rem;margin:1.3em 0 .4em}
article.page{max-width:760px}
.lede{font-size:1.12rem;color:var(--ink-soft)}
.meta{color:var(--ink-soft);font-size:.9rem;margin-bottom:18px}
.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:18px;margin:22px 0}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px}
.card h3{margin-top:0}
.card p{color:var(--ink-soft);margin:.4em 0 1em}
section.band{background:var(--aqua);border-radius:var(--radius);padding:26px;margin:26px 0}
.callout{border-left:5px solid var(--amber);background:#fff8ec;padding:14px 18px;border-radius:0 10px 10px 0;margin:20px 0}
.callout.good{border-color:var(--good);background:#eefaf2}
.callout.bad{border-color:var(--bad);background:#fdf0f0}
table{border-collapse:collapse;width:100%;margin:18px 0;background:#fff}
th,td{border:1px solid var(--line);padding:9px 12px;text-align:left;vertical-align:top}
th{background:var(--aqua)}
ul.tight li{margin:.3em 0}
.breadcrumb{font-size:.9rem;color:var(--ink-soft);margin-bottom:6px}
.breadcrumb a{color:var(--ink-soft)}
details{background:#fff;border:1px solid var(--line);border-radius:10px;padding:12px 16px;margin:10px 0}
summary{font-weight:700;cursor:pointer}
.faq h3{margin-bottom:.2em}
/* Calculator */
.calc{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:24px;margin:22px 0}
.calc label{font-weight:600;display:block;margin-bottom:6px}
.calc input[type=number],.calc select{width:100%;padding:10px 12px;border:1.5px solid #aac6cd;border-radius:9px;
  font-size:1rem;background:#fff;color:var(--ink)}
.grid2{display:grid;grid-template-columns:1fr 1fr;gap:16px}
.grid3{display:grid;grid-template-columns:2fr 1fr auto;gap:10px;align-items:end}
.grid3.eq{grid-template-columns:1fr 1fr 1fr;align-items:start}
.chips{display:flex;gap:8px;flex-wrap:wrap;margin:8px 0 4px}
.chip{border:1.5px solid var(--teal);color:var(--teal-dark);background:#fff;border-radius:999px;
  padding:5px 14px;cursor:pointer;font-size:.92rem;font-weight:600}
.chip:hover,.chip[aria-pressed=true]{background:var(--teal);color:#fff}
.species-row{border-top:1px solid var(--line);padding-top:14px;margin-top:14px}
.remove{background:none;border:0;color:var(--bad);font-size:1.3rem;cursor:pointer;padding:8px;line-height:1}
.result{margin-top:24px;border-top:2px solid var(--aqua);padding-top:18px}
.gauge{background:#e9f1f3;border-radius:999px;height:22px;overflow:hidden;margin:10px 0 4px}
.gauge-fill{height:100%;width:0%;background:var(--good);transition:width .3s ease}
.gauge-fill.warn{background:var(--warn)} .gauge-fill.bad{background:var(--bad)}
.big-pct{font-size:2rem;font-weight:800}
.status{font-weight:700}
.status.good{color:var(--good)} .status.warn{color:var(--warn)} .status.bad{color:var(--bad)}
.warnings{list-style:none;padding:0;margin:14px 0}
.warnings li{padding:10px 14px;border-radius:9px;margin:8px 0;font-size:.96rem}
.warnings li.err{background:#fdf0f0;border:1px solid #f3c2c2}
.warnings li.wr{background:#fff8ec;border:1px solid #f0dcb4}
.warnings li.ok{background:#eefaf2;border:1px solid #bfe6cd}
.small{font-size:.9rem;color:var(--ink-soft)}
/* Footer */
footer.site{background:var(--ink);color:#cfe3e8;margin-top:48px;padding:34px 0 26px}
footer.site a{color:#aee0ea}
footer.site nav ul{list-style:none;padding:0;margin:0 0 14px;display:flex;gap:18px;flex-wrap:wrap}
footer.site nav a{text-decoration:none}
footer.site nav a:hover{text-decoration:underline}
@media (max-width:640px){
  .hero h1{font-size:1.7rem} h1{font-size:1.6rem}
  .grid2,.grid3,.grid3.eq{grid-template-columns:1fr}
  nav.main{margin-left:0}
  body{font-size:16px}
  /* wide tables scroll inside their own box instead of breaking the page layout */
  table{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}
  .hero{padding:36px 0 32px}
  .btn{display:block;text-align:center;margin:0 0 10px}
}