:root{--bg:#f7faf8;--ink:#17211c;--muted:#5b6861;--line:#d8e2dc;--panel:#fff;--soft:#eaf3ee;--accent:#0f766e;--accent2:#0b4f4a;--gold:#bd8b22;--shadow:0 18px 50px rgba(21,45,35,.12);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif}
*{box-sizing:border-box}
body{margin:0;background:var(--bg);color:var(--ink);line-height:1.5}
a{color:inherit}
.wrap{width:min(1120px,calc(100% - 32px));margin:0 auto}
.hero{min-height:62vh;display:grid;align-items:end;color:#fff;background:linear-gradient(90deg,rgba(7,24,20,.82) 0%,rgba(7,24,20,.62) 38%,rgba(7,24,20,.2) 72%),linear-gradient(180deg,rgba(7,24,20,.08),rgba(7,24,20,.64)),url("assets/tiny-useful-tools-hero-a.png") center/cover}
.hero .wrap{padding:92px 0 46px}
.page-hero{min-height:360px;display:grid;align-items:end;color:#fff;background:linear-gradient(90deg,rgba(7,24,20,.84) 0%,rgba(7,24,20,.64) 42%,rgba(7,24,20,.18) 78%),linear-gradient(180deg,rgba(7,24,20,.08),rgba(7,24,20,.62)),var(--page-image) center/cover}
.page-hero .wrap{padding:76px 0 38px}
.page-hero-volume{--page-image:url("assets/aquarium-volume-hero.png")}
.page-hero-co2{--page-image:url("assets/aquarium-co2-hero.png")}
.page-hero-water{--page-image:url("assets/aquarium-hero-tetra-school.png")}
.page-hero-heater{--page-image:url("assets/aquarium-hero-tetra-school.png")}
.page-hero-electricity{--page-image:url("assets/aquarium-hero-tetra-school.png")}
.page-hero-about{--page-image:url("assets/about-tools-hero.png")}
.page-hero-privacy{--page-image:url("assets/privacy-hero.png")}
.page-hero-contact{--page-image:url("assets/contact-hero.png")}
.page-hero h1{max-width:760px}
.page-hero p.copy{max-width:680px;margin:16px 0 0;color:rgba(255,255,255,.9);font-size:18px}
.eyebrow{margin:0 0 12px;color:rgba(255,255,255,.82);font-size:14px;font-weight:800;letter-spacing:.08em;text-transform:uppercase}
h1{max-width:820px;margin:0;font-size:clamp(38px,7vw,76px);line-height:.98;letter-spacing:0}
.hero p.copy{max-width:720px;margin:18px 0 0;color:rgba(255,255,255,.9);font-size:19px}
.topbar{position:sticky;top:0;z-index:10;border-bottom:1px solid rgba(216,226,220,.9);background:rgba(247,250,248,.93);backdrop-filter:blur(14px)}
.topbar .wrap{height:58px;display:flex;align-items:center;justify-content:space-between;gap:16px}
.brand{display:flex;align-items:center;gap:10px;font-weight:850;text-decoration:none}
.brand-mark{width:30px;height:30px;border-radius:8px;display:block;flex:0 0 auto}
.mark{width:30px;height:30px;border-radius:8px;background:linear-gradient(135deg,#2563eb,#0f766e)}
.nav{display:flex;gap:8px;color:var(--muted);font-size:14px}
.nav a{padding:8px 10px;border-radius:8px;text-decoration:none}
.nav a:hover{background:var(--soft);color:var(--ink)}
main{padding:42px 0 72px}
.grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}
.card,.panel{background:var(--panel);border:1px solid var(--line);border-radius:8px;box-shadow:var(--shadow)}
.card{padding:18px;text-decoration:none}
.card h2,.card h3{margin:0 0 8px;font-size:20px}
.card p,.muted{color:var(--muted)}
.card p{margin:0}
.tool-grid{display:grid;grid-template-columns:minmax(0,1.05fr) minmax(320px,.95fr);gap:24px;align-items:start}
.panel{padding:22px}
.field-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
label{display:block;margin-bottom:7px;color:#314039;font-size:13px;font-weight:750}
select,input{width:100%;height:44px;border:1px solid #c8d5ce;border-radius:8px;padding:0 12px;background:#fff;color:var(--ink);font:inherit}
select:focus,input:focus{border-color:var(--accent);outline:3px solid rgba(15,118,110,.16)}
button,.button{min-height:44px;border:0;border-radius:8px;padding:11px 14px;background:var(--accent);color:white;font:inherit;font-weight:800;text-align:center;text-decoration:none;cursor:pointer}
button:hover,.button:hover{background:var(--accent2)}
.result{position:sticky;top:78px;overflow:hidden;padding:0}
.result-head{padding:22px;background:#0d3f3c;color:#fff}
.result-label{margin:0;color:rgba(255,255,255,.72);font-size:13px;font-weight:750;text-transform:uppercase;letter-spacing:.08em}
.price{margin:8px 0 0;font-size:42px;font-weight:850;line-height:1}
.result-body{padding:18px 22px 22px}
.breakdown{display:grid;gap:10px;margin:0 0 18px;padding:0;list-style:none}
.breakdown li{display:flex;justify-content:space-between;gap:14px;padding-bottom:10px;border-bottom:1px solid var(--line);color:var(--muted);font-size:14px}
.breakdown strong{color:var(--ink)}
.ad-slot{display:grid;place-items:center;min-height:110px;margin-top:18px;border:1px dashed #9fb0a7;border-radius:8px;background:#f3f7f5;color:#66756d;font-size:13px;text-align:center}
.content{max-width:820px}
.content h1{font-size:44px;color:var(--ink);line-height:1.08}
.content h2{margin-top:32px}
.footer{border-top:1px solid var(--line);padding:28px 0;color:var(--muted);font-size:13px}
.note{margin:14px 0 0;color:var(--muted);font-size:13px}
@media(max-width:860px){.nav{display:none}.grid,.tool-grid{grid-template-columns:1fr}.result{position:static}}
@media(max-width:560px){.field-grid{grid-template-columns:1fr}.hero{min-height:58vh}.hero .wrap{padding-top:70px}.price{font-size:34px}}


.seo-section{padding:38px 0 0}
.seo-section h2{margin:0 0 12px;font-size:30px;line-height:1.15}
.related-tools{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;margin-top:20px}
.two-column{display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:24px;align-items:start}
.faq{display:grid;gap:12px}
details{border:1px solid var(--line);border-radius:8px;background:#fff;padding:15px 16px}
summary{cursor:pointer;font-weight:800}
details p{margin:10px 0 0;color:var(--muted)}
.monetize-box{padding:22px;border-radius:8px;background:#102f2d;color:#fff}
.monetize-box h3{margin:0 0 8px}
.monetize-box p{margin:0;color:rgba(255,255,255,.76)}
@media(max-width:860px){.related-tools,.two-column{grid-template-columns:1fr}}