*{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;font-size:15px;line-height:1.55;color:#111827;background:#fff;-webkit-font-smoothing:antialiased;overflow-x:hidden}
img,svg{max-width:100%;display:block}
button{font-family:inherit;cursor:pointer;border:0;background:transparent}
a{color:inherit;text-decoration:none}

:root{--text:#111827;--text-mid:#4b5563;--text-light:#6b7280;--bg:#fff;--card-bg:#fff;--border:#e5e7eb;--blue:#2563eb;--blue-hover:#1d4ed8}
html[data-theme="dark"]{--text:#f3f4f6;--text-mid:#d1d5db;--text-light:#9ca3af;--bg:#0f172a;--card-bg:#1e293b;--border:#334155}

body{background:var(--bg);color:var(--text)}

.container{max-width:1000px;margin:0 auto;padding:0 20px}
main{min-height:60vh;padding-bottom:40px}

/* HEADER */
.site-header{background:var(--bg);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:1000}
.header-inner{display:grid;grid-template-columns:1fr auto 1fr;align-items:center;padding:14px 20px;max-width:1100px;margin:0 auto}
.nav-left{justify-self:start}
.nav-center{justify-self:center}
.nav-right{justify-self:end}
.nav-link{font-size:0.9rem;font-weight:500;color:var(--text);padding:6px 10px;border-radius:6px;display:inline-flex;align-items:center;gap:4px}
.nav-link:hover{background:var(--card-bg)}
.chevron{font-size:0.7rem;color:var(--text-light)}
.nav-badge{display:inline-block;padding:6px 12px;font-size:0.75rem;font-weight:700;border:1px solid var(--border);border-radius:6px;letter-spacing:0.08em;color:var(--text)}

/* HERO */
.page-hero{text-align:center;padding:40px 0 20px}
.page-hero h1{font-size:2.25rem;font-weight:800;letter-spacing:-0.025em;color:var(--text);margin-bottom:12px;line-height:1.2}
.page-hero .subtitle{font-size:0.95rem;color:var(--text-mid);max-width:700px;margin:0 auto 16px;line-height:1.6}
.btn-blue{display:inline-block;padding:8px 18px;background:#2563eb;color:#fff;font-size:0.85rem;font-weight:500;border-radius:6px}
.btn-blue:hover{background:#1d4ed8}

/* CALCULATOR BOX */
.calc-box{background:var(--card-bg);border:1px solid var(--border);border-radius:12px;padding:32px;margin:24px 0 40px;box-shadow:0 1px 3px rgba(0,0,0,0.04)}
.calc-field{margin-bottom:20px}
.calc-field:last-child{margin-bottom:0}
.calc-field label{display:block;font-size:0.9rem;font-weight:500;color:var(--text-mid);margin-bottom:8px}
.calc-field input{width:100%;padding:14px 16px;font-size:1rem;font-family:inherit;color:var(--text);background:var(--bg);border:1px solid var(--border);border-radius:8px;outline:none;transition:border-color 0.15s}
.calc-field input:focus{border-color:var(--blue)}

/* CONTENT */
.content-block{margin:40px 0}
.content-block h2{font-size:1.35rem;font-weight:700;color:var(--text);margin-bottom:16px;line-height:1.3}
.content-block p{font-size:0.95rem;color:var(--text-mid);margin-bottom:12px;line-height:1.7}
.formula{background:#fef3c7;padding:8px 12px;border-radius:4px;font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:0.88rem;color:#92400e;display:inline-block;margin:6px 0}
html[data-theme="dark"] .formula{background:rgba(251,191,36,0.15);color:#fbbf24}
.highlight{background:#fef3c7;padding:2px 6px;border-radius:3px;color:#92400e;font-weight:500}
html[data-theme="dark"] .highlight{background:rgba(251,191,36,0.15);color:#fbbf24}

/* TABLE */
.conversion-table{width:100%;border-collapse:collapse;font-size:0.9rem;margin-top:20px}
.conversion-table th{text-align:left;padding:12px 16px;font-weight:500;font-size:0.8rem;color:var(--text-light);border-bottom:1px solid var(--border);background:var(--card-bg)}
.conversion-table td{padding:12px 16px;border-bottom:1px solid var(--border);color:var(--text)}
.conversion-table tr:last-child td{border-bottom:0}
.conversion-table a{color:var(--blue);font-weight:500}
.conversion-table a:hover{text-decoration:underline}

/* DISCOVER BOX */
.discover-box{margin:40px 0;border:1px solid var(--border);border-radius:8px;overflow:hidden;background:var(--card-bg)}
.discover-title{padding:14px 20px;font-size:0.85rem;font-weight:700;color:var(--text);background:#eef2ff;border-bottom:1px solid var(--border);text-transform:uppercase;letter-spacing:0.04em}
html[data-theme="dark"] .discover-title{background:rgba(99,102,241,0.15);color:#c7d2fe}
.discover-row{display:flex;justify-content:space-between;align-items:center;padding:14px 20px;border-bottom:1px solid var(--border);font-size:0.92rem;color:var(--text);transition:background 0.1s}
.discover-row:last-child{border-bottom:0}
.discover-row:hover{background:var(--bg)}
.discover-row .chev{color:var(--text-light);font-size:1.1rem}

/* AD SLOT */
.ad-slot{margin:32px auto;text-align:center;min-height:100px;overflow:hidden}
.ad-slot ins.adsbygoogle{display:block!important;width:100%!important;min-height:100px!important}

/* FOOTER */
.site-footer{margin-top:60px;padding:30px 20px 40px;border-top:1px solid var(--border);background:var(--bg)}
.footer-bottom{max-width:1000px;margin:30px auto 0;display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap}
.footer-copy{font-size:0.82rem;color:var(--text-light)}
.footer-langs{display:flex;gap:6px;flex-wrap:wrap}
.footer-langs a{padding:3px 8px;font-size:0.75rem;color:var(--text-light);border:1px solid var(--border);border-radius:4px}
.footer-langs a:hover{color:var(--text);border-color:var(--text)}
.footer-langs a.active{background:var(--text);color:var(--bg);border-color:var(--text)}

/* RESPONSIVE */
@media (max-width:640px){
    .page-hero h1{font-size:1.65rem}
    .calc-box{padding:20px}
    .container{padding:0 14px}
    .footer-bottom{flex-direction:column;align-items:flex-start}
    .header-inner{padding:10px 14px}
}