/* UseCalculify clone — light theme */
:root{
  --blue:#3B82F6; --blue-dark:#2563EB; --ink:#0F172A; --body:#475569;
  --muted:#64748B; --bg:#F8FAFC; --card:#FFFFFF; --line:#E5E7EB;
  --radius:1rem; --shadow:0 1px 3px rgba(15,23,42,.06),0 4px 14px rgba(15,23,42,.05);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;background:var(--bg);color:var(--body);line-height:1.6;-webkit-font-smoothing:antialiased}
.container{max-width:1140px;margin:0 auto;padding:0 20px}
.container.narrow{max-width:820px}
a{color:var(--blue);text-decoration:none}
h1,h2,h3{color:var(--ink);line-height:1.25}
h1{font-size:2rem;margin:18px 0 8px}
h2{font-size:1.25rem;margin:0 0 14px}
.sec-title{font-size:1.4rem;margin:34px 0 16px}
/* header */
.site-header{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:50}
.nav-inner{display:flex;align-items:center;gap:18px;height:64px}
.brand{display:flex;align-items:center;gap:10px}
.brand-logo{background:var(--blue);border-radius:10px;width:38px;height:38px;display:flex;align-items:center;justify-content:center}
.brand-name{font-weight:800;font-size:1.25rem;color:var(--ink)}
.nav-links{display:flex;gap:4px;margin-left:auto;flex-wrap:nowrap;overflow:hidden}
.nav-link{color:var(--body);font-size:.83rem;font-weight:500;padding:8px 9px;border-radius:8px;white-space:nowrap}
.nav-link:hover{background:#EFF6FF;color:var(--blue-dark)}
.search-btn,.menu-btn{background:#F1F5F9;border:none;border-radius:10px;width:40px;height:40px;display:flex;align-items:center;justify-content:center;cursor:pointer;color:var(--ink)}
.menu-btn{display:none;font-size:1.2rem}
.mobile-nav{display:none;flex-direction:column;padding:10px 20px 16px;background:#fff;border-top:1px solid var(--line)}
.mobile-nav.open{display:flex}
/* search overlay */
.search-overlay{display:none;position:fixed;inset:0;background:rgba(15,23,42,.45);z-index:100;padding:80px 20px 20px}
.search-overlay.open{display:block}
.search-modal{background:#fff;border-radius:16px;max-width:560px;margin:0 auto;box-shadow:0 20px 60px rgba(0,0,0,.2);overflow:hidden}
.search-modal input{width:100%;border:none;outline:none;padding:18px 20px;font-size:1.05rem;border-bottom:1px solid var(--line)}
.search-results{max-height:340px;overflow:auto}
.search-results a{display:flex;justify-content:space-between;align-items:center;padding:12px 20px;color:var(--ink);font-weight:500}
.search-results a:hover{background:#EFF6FF}
.search-results .sc{font-size:.75rem;color:var(--muted);background:#F1F5F9;border-radius:20px;padding:2px 10px}
/* hero */
.hero{background:linear-gradient(180deg,#EFF6FF 0%,var(--bg) 100%);padding:64px 0 40px;text-align:center}
.pill{display:inline-block;background:#DBEAFE;color:#1D4ED8;font-weight:700;font-size:.8rem;border-radius:999px;padding:6px 16px;margin-bottom:16px}
.hero h1{font-size:2.6rem;margin-bottom:12px}
.hero h1 .blue{color:var(--blue)}
.hero-sub{font-size:1.1rem;color:var(--muted);max-width:640px;margin:0 auto 26px}
.hero-search{max-width:620px;margin:0 auto;position:relative}
.hero-search input{width:100%;padding:16px 22px;font-size:1rem;border:1.5px solid var(--line);border-radius:999px;outline:none;box-shadow:var(--shadow)}
.hero-search input:focus{border-color:var(--blue)}
.hero-results{position:absolute;top:105%;left:0;right:0;background:#fff;border-radius:14px;box-shadow:0 12px 40px rgba(0,0,0,.12);overflow:hidden;display:none;text-align:left;z-index:20}
.hero-results.open{display:block;max-height:320px;overflow:auto}
/* category cards */
.cat-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:16px;margin:36px 0}
.cat-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:22px 14px;text-align:center;box-shadow:var(--shadow);transition:transform .15s}
.cat-card:hover{transform:translateY(-3px)}
.cat-ico{font-size:2rem;display:block;margin-bottom:8px}
.cat-name{display:block;font-weight:700;color:var(--ink);font-size:.92rem}
.cat-count{display:block;font-size:.75rem;color:var(--muted)}
/* sections */
.sec-head{display:flex;align-items:baseline;gap:14px;margin:40px 0 16px}
.sec-head h2{font-size:1.5rem;margin:0}
.view-all{margin-left:auto;font-weight:600;font-size:.9rem}
.sec-sub{color:var(--muted);font-size:.9rem}
.card-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}
.card-grid3{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.calc-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:18px;display:flex;flex-direction:column;gap:8px;box-shadow:var(--shadow);transition:transform .15s}
.calc-card:hover{transform:translateY(-2px);border-color:#BFDBFE}
.calc-ico{width:44px;height:44px;border-radius:12px;display:flex;align-items:center;justify-content:center;font-size:1.4rem}
.calc-ico.lg{width:64px;height:64px;font-size:2rem;border-radius:16px}
.calc-name{font-weight:700;color:var(--ink);font-size:.95rem}
.calc-cta{font-size:.82rem;font-weight:600;color:var(--blue)}
.compare-link{display:inline-block;margin:18px 0 8px;font-weight:600}
/* calculator page */
.crumbs{font-size:.85rem;color:var(--muted);margin:22px 0 6px}
.crumbs a{color:var(--muted)}
.calc-head{display:flex;gap:16px;align-items:center;margin-bottom:22px}
.calc-head h1{margin:0;font-size:1.8rem}
.subtitle{color:var(--muted);margin-top:4px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px;margin-bottom:22px}
.calc-layout{display:grid;grid-template-columns:1.15fr 1fr;gap:20px;align-items:start}
.fields{display:flex;flex-direction:column;gap:16px;margin-bottom:18px}
.field{display:flex;flex-direction:column;gap:6px}
.flabel{font-weight:600;font-size:.88rem;color:var(--ink)}
.help{font-weight:400;color:var(--muted);font-size:.78rem;display:block}
.input-wrap{display:flex;align-items:stretch;border:1.5px solid var(--line);border-radius:10px;overflow:hidden;background:#fff}
.input-wrap:focus-within{border-color:var(--blue)}
.affix{background:#F1F5F9;padding:0 12px;display:flex;align-items:center;color:var(--muted);font-weight:600;font-size:.9rem}
.input-wrap input{border:none;outline:none;padding:11px 12px;font-size:1rem;width:100%;background:transparent}
.text-in{border:1.5px solid var(--line);border-radius:10px;padding:11px 12px;font-size:1rem;width:100%;outline:none;background:#fff;font-family:inherit}
.text-in:focus{border-color:var(--blue)}
textarea.text-in{resize:vertical}
select.text-in{appearance:none}
input[type=range]{width:100%;accent-color:var(--blue);height:28px}
.slider-val{color:var(--blue)}
.toggle-row{flex-direction:row!important;justify-content:space-between;align-items:center}
.switch{position:relative;width:46px;height:26px;flex-shrink:0}
.switch input{opacity:0;width:100%;height:100%;position:absolute;cursor:pointer;z-index:2;margin:0}
.switch .knob{position:absolute;inset:0;background:#CBD5E1;border-radius:999px;transition:.2s}
.switch .knob:before{content:"";position:absolute;width:20px;height:20px;background:#fff;border-radius:50%;top:3px;left:3px;transition:.2s;box-shadow:0 1px 3px rgba(0,0,0,.25)}
.switch input:checked + .knob{background:var(--blue)}
.switch input:checked + .knob:before{left:23px}
.tabs{display:flex;background:#F1F5F9;border-radius:12px;padding:4px;gap:4px;flex-wrap:wrap}
.tab{flex:1;border:none;background:transparent;padding:9px 8px;border-radius:9px;font-weight:600;font-size:.85rem;color:var(--muted);cursor:pointer;white-space:nowrap}
.tab.active{background:#fff;color:var(--blue-dark);box-shadow:0 1px 3px rgba(0,0,0,.12)}
.btn-primary{background:var(--blue);color:#fff;border:none;border-radius:10px;padding:13px 26px;font-size:1rem;font-weight:700;cursor:pointer;transition:.15s}
.btn-primary:hover{background:var(--blue-dark)}
.btn-block{width:100%}
.results-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px}
.res-card{background:#F8FAFC;border:1px solid var(--line);border-radius:12px;padding:14px}
.res-card.big{grid-column:1/-1;background:#EFF6FF;border-color:#BFDBFE}
.res-label{display:block;font-size:.78rem;color:var(--muted);font-weight:600;margin-bottom:4px}
.res-val{display:block;font-size:1.25rem;font-weight:800;color:var(--ink)}
.res-card.big .res-val{font-size:1.9rem;color:var(--blue-dark)}
.chart-card{grid-column:1/-1}
.callout{background:#FFFBEB;border:1px solid #FDE68A;border-radius:12px;padding:14px 18px;margin-bottom:20px;font-size:.9rem;color:#92400E}
/* keypad */
.keypad{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-bottom:16px}
.key{border:1px solid var(--line);background:#F8FAFC;border-radius:10px;padding:14px;font-size:1.1rem;font-weight:600;cursor:pointer;color:var(--ink)}
.key:hover{background:#EFF6FF;border-color:#BFDBFE}
.key.op{background:#DBEAFE;color:#1D4ED8}
.key.eq{background:var(--blue);color:#fff;grid-column:span 2}
.calc-display{background:#0F172A;color:#fff;border-radius:12px;padding:18px;font-size:1.8rem;text-align:right;font-family:ui-monospace,monospace;margin-bottom:14px;min-height:76px;word-break:break-all}
.calc-display small{display:block;font-size:.85rem;color:#94A3B8}
/* prose / faq */
.prose p{margin-bottom:12px}
.prose h3{margin:18px 0 8px;font-size:1.05rem}
.prose ul,.prose ol{margin:0 0 12px 22px}
.prose table{width:100%;border-collapse:collapse;margin:12px 0;font-size:.9rem}
.prose th,.prose td{border:1px solid var(--line);padding:8px 10px;text-align:left}
.prose th{background:#F1F5F9}
.faq-item{border-bottom:1px solid var(--line)}
.faq-item:last-child{border-bottom:none}
.faq-q{width:100%;background:none;border:none;text-align:left;padding:14px 0;font-weight:600;color:var(--ink);font-size:.95rem;cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:10px}
.faq-q span{color:var(--blue);font-size:1.3rem;flex-shrink:0}
.faq-a{display:none;padding:0 0 16px;color:var(--body);font-size:.92rem}
.faq-item.open .faq-a{display:block}
.faq-item.open .faq-q span{transform:rotate(45deg)}
/* blog */
.post-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px;margin:24px 0 40px}
.post-card{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:20px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:8px}
.post-card:hover{border-color:#BFDBFE}
.post-date{font-size:.78rem;color:var(--muted);font-weight:600}
.post-title{font-weight:700;color:var(--ink);font-size:1.02rem}
.post-ex{font-size:.88rem;color:var(--muted)}
/* footer */
.site-footer{background:#fff;border-top:1px solid var(--line);margin-top:60px;padding:44px 0 0}
.foot-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:24px}
.foot-col{display:flex;flex-direction:column;gap:7px}
.foot-cat{font-weight:700;color:var(--ink);font-size:.88rem;margin-bottom:4px}
.foot-col a{font-size:.82rem;color:var(--muted)}
.foot-col a:hover{color:var(--blue)}
.foot-more{font-weight:600!important;color:var(--blue)!important}
.foot-bottom{border-top:1px solid var(--line);margin-top:32px;padding:18px 0;display:flex;justify-content:space-between;align-items:center;font-size:.82rem;color:var(--muted);flex-wrap:wrap;gap:10px}
.foot-links{display:flex;gap:18px}
.foot-links a{color:var(--muted)}
/* responsive */
@media(max-width:900px){
  .cat-grid{grid-template-columns:repeat(2,1fr)}
  .card-grid{grid-template-columns:repeat(2,1fr)}
  .card-grid3,.post-grid{grid-template-columns:1fr 1fr}
  .calc-layout{grid-template-columns:1fr}
  .foot-grid{grid-template-columns:repeat(3,1fr)}
  .nav-links{display:none}
  .menu-btn{display:flex}
  .hero h1{font-size:2rem}
}
@media(max-width:560px){
  .card-grid,.card-grid3,.post-grid{grid-template-columns:1fr}
  .foot-grid{grid-template-columns:1fr 1fr}
  .results-grid{grid-template-columns:1fr}
}