/* =========================================================
   HydraFit.online — Core Stylesheet
   Professional Health & Fitness Tools Website
   ========================================================= */

:root{
  --brand-teal:#0d9488;
  --brand-teal-dark:#0f766e;
  --brand-teal-light:#ccfbf1;
  --brand-blue:#0369a1;
  --brand-accent:#f97316;
  --ink-900:#0f172a;
  --ink-700:#334155;
  --ink-500:#64748b;
  --ink-300:#cbd5e1;
  --ink-100:#f1f5f9;
  --surface:#ffffff;
  --surface-alt:#f8fafc;
  --success:#16a34a;
  --danger:#dc2626;
  --warning:#d97706;
  --radius-sm:8px;
  --radius-md:14px;
  --radius-lg:22px;
  --shadow-sm:0 1px 3px rgba(15,23,42,.08), 0 1px 2px rgba(15,23,42,.06);
  --shadow-md:0 8px 24px rgba(15,23,42,.08);
  --shadow-lg:0 20px 45px rgba(15,23,42,.12);
  --max-width:1180px;
  --font-body:'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --font-head:'Poppins', var(--font-body);
}

*,*::before,*::after{box-sizing:border-box;}
html{scroll-behavior:smooth;}
body{
  margin:0;
  font-family:var(--font-body);
  color:var(--ink-700);
  background:var(--surface-alt);
  line-height:1.65;
  -webkit-font-smoothing:antialiased;
}
h1,h2,h3,h4,h5{
  font-family:var(--font-head);
  color:var(--ink-900);
  line-height:1.25;
  margin:0 0 .6em;
  font-weight:700;
}
h1{font-size:clamp(1.9rem,4vw,2.8rem);}
h2{font-size:clamp(1.4rem,2.6vw,2rem);}
h3{font-size:1.2rem;}
p{margin:0 0 1em;}
a{color:var(--brand-teal-dark);text-decoration:none;}
a:hover{text-decoration:underline;}
ul,ol{padding-left:1.3em;}
img{max-width:100%;display:block;}
.container{max-width:var(--max-width);margin:0 auto;padding:0 20px;}
.visually-hidden{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;}

/* ---------- Buttons ---------- */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:.5em;
  padding:.85em 1.6em;border-radius:999px;font-weight:600;font-size:.98rem;
  cursor:pointer;border:2px solid transparent;transition:.2s ease;
}
.btn-primary{background:var(--brand-teal);color:#fff;}
.btn-primary:hover{background:var(--brand-teal-dark);text-decoration:none;transform:translateY(-1px);}
.btn-outline{background:transparent;border-color:var(--brand-teal);color:var(--brand-teal-dark);}
.btn-outline:hover{background:var(--brand-teal-light);text-decoration:none;}
.btn-accent{background:var(--brand-accent);color:#fff;}
.btn-accent:hover{background:#ea580c;text-decoration:none;}
.btn-block{width:100%;}

/* ---------- Header ---------- */
.site-header{
  position:sticky;top:0;z-index:1000;
  background:rgba(255,255,255,.92);
  backdrop-filter:saturate(180%) blur(10px);
  border-bottom:1px solid var(--ink-100);
}
.header-inner{display:flex;align-items:center;justify-content:space-between;padding:14px 20px;max-width:var(--max-width);margin:0 auto;}
.brand{display:flex;align-items:center;gap:10px;font-family:var(--font-head);font-weight:800;font-size:1.35rem;color:var(--ink-900);}
.brand .brand-mark{
  width:38px;height:38px;border-radius:10px;
  background:linear-gradient(135deg,var(--brand-teal),var(--brand-blue));
  display:flex;align-items:center;justify-content:center;color:#fff;font-size:1.1rem;
}
.brand span{color:var(--brand-teal-dark);}
.main-nav{display:flex;align-items:center;gap:6px;}
.main-nav a{
  color:var(--ink-700);font-weight:600;padding:10px 14px;border-radius:999px;font-size:.95rem;
}
.main-nav a:hover,.main-nav a.active{background:var(--brand-teal-light);color:var(--brand-teal-dark);text-decoration:none;}
.nav-cta{margin-left:6px;}
.nav-toggle{display:none;background:none;border:none;font-size:1.6rem;cursor:pointer;color:var(--ink-900);}

.has-dropdown{position:relative;}
.dropdown{
  position:absolute;top:100%;left:0;background:#fff;min-width:280px;border-radius:var(--radius-md);
  box-shadow:var(--shadow-lg);padding:10px;display:none;grid-template-columns:1fr 1fr;gap:2px;
  border:1px solid var(--ink-100);
}
.has-dropdown:hover .dropdown,.has-dropdown:focus-within .dropdown{display:grid;}
.dropdown a{padding:8px 10px;font-size:.85rem;border-radius:8px;font-weight:500;}
.dropdown a:hover{background:var(--brand-teal-light);}

@media (max-width:920px){
  .main-nav{
    position:fixed;top:70px;left:0;right:0;bottom:0;background:#fff;flex-direction:column;
    align-items:stretch;padding:20px;gap:4px;overflow-y:auto;transform:translateX(100%);
    transition:transform .25s ease;
  }
  .main-nav.open{transform:translateX(0);}
  .has-dropdown .dropdown{display:grid;position:static;box-shadow:none;border:none;grid-template-columns:1fr;padding:0 0 0 10px;}
  .nav-toggle{display:block;}
  .nav-cta{margin:10px 0 0;}
}

/* ---------- Hero ---------- */
.hero{
  background:radial-gradient(circle at 20% 20%,#e0f2fe 0%,rgba(224,242,254,0) 55%),
             radial-gradient(circle at 85% 15%,var(--brand-teal-light) 0%,rgba(204,251,241,0) 50%),
             linear-gradient(180deg,#ffffff 0%,#f8fafc 100%);
  padding:70px 0 60px;border-bottom:1px solid var(--ink-100);
}
.hero-inner{display:grid;grid-template-columns:1.1fr .9fr;gap:40px;align-items:center;}
.eyebrow{
  display:inline-block;background:var(--brand-teal-light);color:var(--brand-teal-dark);
  font-weight:700;font-size:.78rem;letter-spacing:.06em;text-transform:uppercase;
  padding:6px 14px;border-radius:999px;margin-bottom:16px;
}
.hero p.lead{font-size:1.15rem;color:var(--ink-700);max-width:56ch;}
.hero-actions{display:flex;gap:14px;flex-wrap:wrap;margin-top:26px;}
.hero-stats{display:flex;gap:28px;margin-top:36px;flex-wrap:wrap;}
.hero-stats div strong{display:block;font-size:1.6rem;font-family:var(--font-head);color:var(--brand-teal-dark);}
.hero-stats div span{font-size:.85rem;color:var(--ink-500);}
.hero-art{
  background:linear-gradient(135deg,var(--brand-teal),var(--brand-blue));
  border-radius:var(--radius-lg);padding:34px;color:#fff;box-shadow:var(--shadow-lg);
}
.hero-art ul{list-style:none;padding:0;margin:0;display:grid;gap:14px;}
.hero-art li{display:flex;align-items:center;gap:12px;background:rgba(255,255,255,.12);padding:12px 16px;border-radius:12px;font-weight:600;font-size:.95rem;}
.hero-art .icon{font-size:1.3rem;}

/* ---------- Sections ---------- */
.section{padding:64px 0;}
.section-alt{background:#fff;}
.section-head{text-align:center;max-width:680px;margin:0 auto 40px;}
.section-head p{color:var(--ink-500);}

/* ---------- Tool grid / cards ---------- */
.tool-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(270px,1fr));gap:22px;}
.tool-card{
  background:#fff;border:1px solid var(--ink-100);border-radius:var(--radius-md);padding:26px;
  box-shadow:var(--shadow-sm);transition:.2s ease;display:flex;flex-direction:column;height:100%;
}
.tool-card:hover{box-shadow:var(--shadow-md);transform:translateY(-3px);border-color:var(--brand-teal);}
.tool-card .icon-badge{
  width:52px;height:52px;border-radius:14px;background:var(--brand-teal-light);
  display:flex;align-items:center;justify-content:center;font-size:1.6rem;margin-bottom:14px;
}
.tool-card h3{margin-bottom:.4em;font-size:1.1rem;}
.tool-card p{color:var(--ink-500);font-size:.92rem;flex-grow:1;}
.tool-card .card-link{font-weight:700;color:var(--brand-teal-dark);font-size:.9rem;margin-top:12px;display:inline-block;}
.tag{
  display:inline-block;font-size:.7rem;font-weight:700;text-transform:uppercase;letter-spacing:.04em;
  color:var(--brand-blue);background:#e0f2fe;padding:3px 10px;border-radius:999px;margin-bottom:10px;
}

/* ---------- Category filter ---------- */
.filter-bar{display:flex;gap:10px;flex-wrap:wrap;justify-content:center;margin-bottom:36px;}
.filter-bar button{
  border:1px solid var(--ink-300);background:#fff;padding:8px 18px;border-radius:999px;
  font-weight:600;font-size:.88rem;cursor:pointer;color:var(--ink-700);transition:.15s;
}
.filter-bar button.active,.filter-bar button:hover{background:var(--brand-teal);border-color:var(--brand-teal);color:#fff;}

/* ---------- Breadcrumb ---------- */
.breadcrumb{font-size:.85rem;color:var(--ink-500);padding:16px 0 0;}
.breadcrumb a{color:var(--ink-500);}
.breadcrumb span{margin:0 6px;}

/* ---------- Calculator layout ---------- */
.tool-hero{padding:34px 0 10px;}
.tool-layout{display:grid;grid-template-columns:1fr;gap:34px;padding:20px 0 10px;}
.calc-card{
  background:#fff;border:1px solid var(--ink-100);border-radius:var(--radius-lg);
  padding:30px clamp(20px,4vw,40px);box-shadow:var(--shadow-md);
}
.calc-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:18px;margin-bottom:8px;}
.field{display:flex;flex-direction:column;gap:6px;}
.field label{font-weight:600;font-size:.88rem;color:var(--ink-900);}
.field small{color:var(--ink-500);font-weight:400;}
.field input,.field select{
  padding:12px 14px;border-radius:var(--radius-sm);border:1.5px solid var(--ink-300);font-size:1rem;
  font-family:inherit;background:#fff;color:var(--ink-900);
}
.field input:focus,.field select:focus{outline:none;border-color:var(--brand-teal);box-shadow:0 0 0 3px var(--brand-teal-light);}
.radio-row{display:flex;gap:16px;flex-wrap:wrap;}
.radio-row label{display:flex;align-items:center;gap:6px;font-weight:500;font-size:.92rem;color:var(--ink-700);}
.unit-toggle{display:flex;background:var(--ink-100);border-radius:999px;padding:4px;gap:4px;width:max-content;margin-bottom:10px;}
.unit-toggle button{border:none;background:transparent;padding:7px 16px;border-radius:999px;font-weight:600;font-size:.85rem;cursor:pointer;color:var(--ink-500);}
.unit-toggle button.active{background:#fff;color:var(--brand-teal-dark);box-shadow:var(--shadow-sm);}
.calc-actions{display:flex;gap:12px;margin-top:20px;flex-wrap:wrap;}

.result-panel{
  margin-top:26px;padding:24px;border-radius:var(--radius-md);background:var(--surface-alt);
  border:1.5px dashed var(--ink-300);display:none;
}
.result-panel.show{display:block;animation:fadeIn .3s ease;}
@keyframes fadeIn{from{opacity:0;transform:translateY(6px);}to{opacity:1;transform:translateY(0);}}
.result-headline{font-size:2.1rem;font-family:var(--font-head);font-weight:800;color:var(--brand-teal-dark);margin-bottom:4px;}
.result-sub{color:var(--ink-500);margin-bottom:16px;}
.result-badge{display:inline-block;padding:6px 16px;border-radius:999px;font-weight:700;font-size:.9rem;margin-bottom:14px;}
.badge-good{background:#dcfce7;color:var(--success);}
.badge-warn{background:#fef3c7;color:var(--warning);}
.badge-bad{background:#fee2e2;color:var(--danger);}
.badge-info{background:#e0f2fe;color:var(--brand-blue);}
.result-table{width:100%;border-collapse:collapse;margin-top:10px;}
.result-table td,.result-table th{padding:10px 12px;border-bottom:1px solid var(--ink-100);text-align:left;font-size:.92rem;}
.result-table th{color:var(--ink-500);font-weight:600;width:55%;}
.range-bar{height:10px;border-radius:6px;background:linear-gradient(90deg,#38bdf8 0%,#22c55e 30%,#facc15 60%,#f97316 80%,#ef4444 100%);position:relative;margin:18px 0 6px;}
.range-marker{position:absolute;top:-6px;width:4px;height:22px;background:var(--ink-900);border-radius:2px;transform:translateX(-2px);}
.range-labels{display:flex;justify-content:space-between;font-size:.72rem;color:var(--ink-500);}

/* ---------- Content / article ---------- */
.article{max-width:820px;margin:0 auto;}
.article h2{margin-top:1.6em;}
.article table{width:100%;border-collapse:collapse;margin:1.2em 0;}
.article table th,.article table td{border:1px solid var(--ink-100);padding:10px 14px;text-align:left;font-size:.92rem;}
.article table th{background:var(--surface-alt);}
.callout{
  background:var(--brand-teal-light);border-left:4px solid var(--brand-teal);padding:16px 20px;
  border-radius:8px;margin:22px 0;
}
.callout.warn{background:#fef3c7;border-left-color:var(--warning);}
.callout strong{color:var(--ink-900);}

/* ---------- FAQ ---------- */
.faq-item{border-bottom:1px solid var(--ink-100);padding:18px 0;}
.faq-item h3{cursor:pointer;display:flex;justify-content:space-between;align-items:center;margin:0;font-size:1rem;}
.faq-item h3::after{content:'+';font-size:1.4rem;color:var(--brand-teal);}
.faq-item.open h3::after{content:'\2212';}
.faq-item p{display:none;margin:12px 0 0;color:var(--ink-700);}
.faq-item.open p{display:block;}

/* ---------- Related tools ---------- */
.related-list{display:flex;flex-wrap:wrap;gap:10px;}
.related-list a{
  background:#fff;border:1px solid var(--ink-300);padding:8px 16px;border-radius:999px;font-weight:600;font-size:.87rem;
}
.related-list a:hover{background:var(--brand-teal-light);border-color:var(--brand-teal);text-decoration:none;}

/* ---------- Trust strip ---------- */
.trust-strip{background:var(--ink-900);color:#e2e8f0;padding:34px 0;}
.trust-strip .container{display:flex;flex-wrap:wrap;gap:24px;justify-content:space-around;text-align:center;}
.trust-strip div{flex:1;min-width:150px;}
.trust-strip strong{display:block;font-size:1.5rem;color:#fff;font-family:var(--font-head);}
.trust-strip span{font-size:.82rem;color:#94a3b8;}

/* ---------- CTA banner ---------- */
.cta-banner{
  background:linear-gradient(135deg,var(--brand-teal-dark),var(--brand-blue));
  color:#fff;border-radius:var(--radius-lg);padding:48px;text-align:center;margin:20px 0;
}
.cta-banner h2{color:#fff;}
.cta-banner p{color:#e0f2fe;max-width:60ch;margin:0 auto 22px;}

/* ---------- Footer ---------- */
.site-footer{background:var(--ink-900);color:#cbd5e1;padding:56px 0 24px;margin-top:40px;}
.footer-grid{display:grid;grid-template-columns:1.5fr 1fr 1fr 1fr;gap:32px;margin-bottom:36px;}
.footer-grid h4{color:#fff;font-size:.95rem;margin-bottom:14px;}
.footer-grid ul{list-style:none;padding:0;margin:0;display:grid;gap:9px;}
.footer-grid a{color:#94a3b8;font-size:.9rem;}
.footer-grid a:hover{color:#fff;}
.footer-brand p{color:#94a3b8;font-size:.9rem;max-width:38ch;}
.footer-bottom{border-top:1px solid #1e293b;padding-top:22px;display:flex;justify-content:space-between;flex-wrap:wrap;gap:10px;font-size:.82rem;color:#64748b;}
.footer-social{display:flex;gap:12px;}
.footer-social a{width:36px;height:36px;border-radius:50%;background:#1e293b;display:flex;align-items:center;justify-content:center;color:#fff;}

@media(max-width:900px){
  .hero-inner{grid-template-columns:1fr;}
  .footer-grid{grid-template-columns:1fr 1fr;}
}
@media(max-width:600px){
  .footer-grid{grid-template-columns:1fr;}
  .cta-banner{padding:30px 20px;}
}

/* ---------- Misc pages ---------- */
.page-header{padding:50px 0 20px;text-align:center;background:linear-gradient(180deg,#fff,var(--surface-alt));}
.updated-note{color:var(--ink-500);font-size:.85rem;font-style:italic;}
.toc{background:#fff;border:1px solid var(--ink-100);border-radius:var(--radius-md);padding:20px 26px;margin:20px 0 30px;}
.toc h2{font-size:1rem;margin-bottom:10px;}
.toc ul{margin:0;}
.author-box{display:flex;gap:16px;align-items:center;background:#fff;border:1px solid var(--ink-100);border-radius:var(--radius-md);padding:20px;margin:30px 0;}
.author-box .avatar{width:56px;height:56px;border-radius:50%;background:var(--brand-teal-light);display:flex;align-items:center;justify-content:center;font-size:1.4rem;color:var(--brand-teal-dark);font-weight:700;}