/* AquaCalcs — shared styles */
:root{
  --bg:#f2f7f6;
  --card:#ffffff;
  --ink:#17333b;
  --muted:#54707a;
  --brand:#0e6b74;
  --brand-deep:#0a4d55;
  --tint:#e1efed;
  --tint-2:#d0e6e3;
  --line:#d9e6e4;
  --accent:#e0912f;
  --danger:#b23a3a;
  --danger-bg:#fdf1ef;
  --warn-bg:#fff7e8;
  --warn-line:#e8c27a;
  --ok:#2e7d4f;
  --radius:14px;
  --shadow:0 1px 2px rgba(23,51,59,.06),0 8px 24px -12px rgba(14,107,116,.18);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{
  margin:0;
  font-family:"Karla",-apple-system,"Segoe UI",sans-serif;
  font-size:17px;line-height:1.65;
  color:var(--ink);
  background:var(--bg);
  background-image:radial-gradient(1200px 400px at 80% -10%,rgba(14,107,116,.08),transparent 60%);
}
h1,h2,h3{font-family:"Fraunces","Georgia",serif;font-weight:600;line-height:1.25;color:var(--brand-deep);letter-spacing:-.01em}
h1{font-size:clamp(1.7rem,4vw,2.4rem);margin:.2em 0 .4em}
h2{font-size:1.45rem;margin:2em 0 .6em}
h3{font-size:1.13rem;margin:1.4em 0 .4em}
p{margin:.7em 0}
a{color:var(--brand);text-underline-offset:3px}
a:hover{color:var(--brand-deep)}
code{background:var(--tint);padding:.12em .4em;border-radius:6px;font-size:.9em}
.wrap{max-width:960px;margin:0 auto;padding:0 20px}
.narrow{max-width:780px}

/* header */
.site-head{background:var(--card);border-bottom:1px solid var(--line)}
.site-head .wrap{display:flex;align-items:center;justify-content:space-between;padding-top:14px;padding-bottom:14px;gap:12px;flex-wrap:wrap}
.logo{display:flex;align-items:center;gap:9px;font-family:"Fraunces",serif;font-size:1.3rem;font-weight:700;color:var(--brand-deep);text-decoration:none}
.logo svg{flex:none}
.logo span b{color:var(--brand)}
.site-nav{display:flex;gap:4px;flex-wrap:wrap}
.site-nav a{color:var(--muted);text-decoration:none;font-size:.95rem;padding:6px 12px;border-radius:999px}
.site-nav a:hover,.site-nav a[aria-current]{background:var(--tint);color:var(--brand-deep)}

/* hero (index) */
.hero{padding:52px 0 30px;text-align:left}
.hero h1{font-size:clamp(2rem,5vw,3rem)}
.hero p{max-width:620px;color:var(--muted);font-size:1.1rem}
.kicker{display:inline-block;font-size:.8rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--brand);background:var(--tint);padding:4px 12px;border-radius:999px;margin-bottom:10px}

/* tool card grid */
.cat-title{margin-top:2.2em;display:flex;align-items:center;gap:10px}
.cat-title::after{content:"";flex:1;height:1px;background:var(--line)}
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:14px;margin:16px 0}
.tool-card{display:block;background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px 18px 16px;text-decoration:none;color:inherit;box-shadow:var(--shadow);transition:transform .15s ease,border-color .15s ease}
.tool-card:hover{transform:translateY(-2px);border-color:var(--brand)}
.tool-card .t-ic{font-size:1.5rem;display:block;margin-bottom:6px}
.tool-card h3{margin:0 0 4px;font-size:1.05rem}
.tool-card p{margin:0;font-size:.88rem;color:var(--muted);line-height:1.5}

/* breadcrumb */
.crumbs{font-size:.85rem;color:var(--muted);margin:22px 0 6px}
.crumbs a{color:var(--muted)}

/* calculator */
.calc{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px;margin:24px 0 10px}
.calc h2{margin:0 0 14px;font-size:1.2rem}
.calc-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:14px}
.field label{display:block;font-size:.83rem;font-weight:700;color:var(--muted);margin-bottom:5px;letter-spacing:.02em}
.field input,.field select{width:100%;padding:10px 12px;font:inherit;color:var(--ink);border:1.5px solid var(--line);border-radius:10px;background:#fbfdfd}
.field input:focus,.field select:focus{outline:2px solid var(--brand);outline-offset:1px;border-color:var(--brand)}
.calc button{margin-top:16px;padding:11px 26px;font:inherit;font-weight:700;color:#fff;background:var(--brand);border:0;border-radius:10px;cursor:pointer}
.calc button:hover{background:var(--brand-deep)}
.result{margin-top:16px;padding:16px 18px;background:var(--tint);border-radius:10px;font-size:.98rem;display:none}
.result.show{display:block}
.result .big{font-family:"Fraunces",serif;font-size:1.7rem;font-weight:700;color:var(--brand-deep);display:block;margin-bottom:2px}
.result small{color:var(--muted)}
.unit-note{font-size:.82rem;color:var(--muted);margin-top:10px}

/* content blocks */
.note{background:var(--tint);border-left:4px solid var(--brand);border-radius:0 10px 10px 0;padding:12px 16px;font-size:.95rem;margin:18px 0}
.warnbox{background:var(--warn-bg);border:1.5px solid var(--warn-line);border-radius:12px;padding:16px 18px;font-size:.95rem;margin:18px 0}
.dangerbox{background:var(--danger-bg);border:2px solid var(--danger);border-radius:12px;padding:18px 20px;margin:20px 0}
.dangerbox strong:first-child{color:var(--danger);font-size:1.02rem}
ul,ol{padding-left:1.3em}
li{margin:.35em 0}
table{border-collapse:collapse;width:100%;font-size:.92rem;margin:14px 0}
th,td{border:1px solid var(--line);padding:8px 10px;text-align:left}
th{background:var(--tint);font-weight:700}
.tablewrap{overflow-x:auto}
.formula{background:var(--card);border:1px dashed var(--tint-2);border-radius:10px;padding:12px 16px;font-family:ui-monospace,Menlo,monospace;font-size:.92rem;overflow-x:auto}

/* FAQ */
details{background:var(--card);border:1px solid var(--line);border-radius:10px;margin:8px 0;padding:0 16px}
details summary{cursor:pointer;font-weight:700;padding:12px 0;list-style-position:outside}
details[open]{border-color:var(--brand)}
details p{margin-top:0;color:#2b4750}

/* related tools */
.related{margin:36px 0 10px;padding:20px;background:var(--card);border:1px solid var(--line);border-radius:var(--radius)}
.related h2{margin:0 0 10px;font-size:1.1rem}
.related ul{margin:0;padding:0;list-style:none;display:flex;flex-wrap:wrap;gap:8px}
.related a{display:inline-block;background:var(--tint);color:var(--brand-deep);text-decoration:none;font-size:.9rem;font-weight:700;padding:7px 14px;border-radius:999px}
.related a:hover{background:var(--tint-2)}

/* footer */
.site-foot{margin-top:60px;background:var(--brand-deep);color:#cfe5e3;font-size:.9rem}
.site-foot .wrap{padding:34px 20px 28px;display:flex;flex-wrap:wrap;gap:26px;justify-content:space-between}
.site-foot a{color:#fff;text-decoration:none}
.site-foot a:hover{text-decoration:underline}
.site-foot nav{display:flex;gap:18px;flex-wrap:wrap}
.site-foot .fine{flex-basis:100%;font-size:.8rem;color:#9fc4c1;border-top:1px solid rgba(255,255,255,.15);padding-top:14px;margin-top:2px}

@media (max-width:640px){
  body{font-size:16px}
  .calc{padding:18px}
  .site-foot .wrap{gap:14px}
}

/* pH/KH/CO2 chart */
.co2t td{text-align:center;padding:6px 5px;font-variant-numeric:tabular-nums;min-width:40px}
.co2t th{white-space:nowrap}
.co2t td.c-lo{background:#e8f1fb;color:#3c5a77}
.co2t td.c-ok{background:#dff2e4;color:#1f5c39;font-weight:700}
.co2t td.c-hi{background:#fff3d6;color:#7a5a14}
.co2t td.c-vh{background:#fbe3e3;color:#8f2727}
.co2t td.c-you{outline:3px solid var(--brand);outline-offset:-3px;position:relative}

/* cycle timeline */
.tl{list-style:none;padding:0;margin:14px 0}
.tl li{position:relative;padding:0 0 18px 26px;border-left:2.5px solid var(--tint-2);margin-left:8px}
.tl li:last-child{border-left-color:transparent}
.tl li::before{content:"";position:absolute;left:-8px;top:2px;width:13px;height:13px;border-radius:50%;background:var(--brand);border:2.5px solid #fff;box-shadow:0 0 0 1.5px var(--brand)}
.tl .tl-date{font-weight:700;color:var(--brand-deep);font-size:.9rem}