/* Easy GPA Converter — styles */
:root{
  --bg:#ffffff;
  --bg-soft:#f6f8fb;
  --surface:#ffffff;
  --border:#e4e9f0;
  --text:#0f172a;
  --muted:#475569;
  --primary:#1e40af;
  --primary-600:#1d4ed8;
  --primary-50:#eff4ff;
  --accent:#2563eb;
  --success:#15803d;
  --warning:#b45309;
  --danger:#b91c1c;
  --radius:14px;
  --radius-sm:10px;
  --shadow-sm:0 1px 2px rgba(15,23,42,.04), 0 1px 3px rgba(15,23,42,.06);
  --shadow:0 4px 12px rgba(15,23,42,.06), 0 2px 4px rgba(15,23,42,.04);
  --shadow-lg:0 20px 40px -20px rgba(15,23,42,.18);
  --container:1120px;
  --font:'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}
[data-theme="dark"]{
  --bg:#0b1220;
  --bg-soft:#0f1a2e;
  --surface:#111c33;
  --border:#1f2c46;
  --text:#e6edf7;
  --muted:#9aa7bd;
  --primary:#60a5fa;
  --primary-600:#3b82f6;
  --primary-50:#0f1f3d;
  --accent:#93c5fd;
  --shadow-sm:0 1px 2px rgba(0,0,0,.4);
  --shadow:0 6px 16px rgba(0,0,0,.45);
  --shadow-lg:0 24px 48px -20px rgba(0,0,0,.6);
}
*{box-sizing:border-box}
html{scroll-behavior:smooth;-webkit-text-size-adjust:100%}
body{margin:0;font-family:var(--font);background:var(--bg);color:var(--text);line-height:1.65;font-size:16px;-webkit-font-smoothing:antialiased}
img{max-width:100%;display:block}
a{color:var(--primary-600);text-decoration:none}
a:hover{text-decoration:underline}
h1,h2,h3,h4{line-height:1.25;color:var(--text);margin:0 0 .6em;font-weight:700;letter-spacing:-.01em}
h1{font-size:clamp(1.9rem,4vw,2.6rem)}
h2{font-size:clamp(1.45rem,2.6vw,1.9rem)}
h3{font-size:1.15rem}
p{margin:0 0 1em}
.muted{color:var(--muted)}
.container{max-width:var(--container);margin:0 auto;padding:0 20px}
.narrow{max-width:760px}
.section{padding:64px 0}
.section.tight{padding:40px 0}
.bg-soft{background:var(--bg-soft)}
.lede{color:var(--muted);font-size:1.05rem;max-width:680px}
.skip-link{position:absolute;left:-9999px;top:0;background:var(--primary);color:#fff;padding:10px 14px;z-index:200}
.skip-link:focus{left:8px;top:8px}

/* Header */
.site-header{position:sticky;top:0;z-index:50;background:color-mix(in srgb,var(--bg) 92%,transparent);backdrop-filter:saturate(180%) blur(10px);border-bottom:1px solid var(--border)}
.nav-wrap{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;color:var(--text);text-decoration:none}
.brand:hover{text-decoration:none}
.brand-mark{display:inline-grid;place-items:center;width:34px;height:34px;border-radius:10px;background:var(--primary);color:#fff;font-weight:800;font-size:.85rem;letter-spacing:.5px}
.brand-text{font-size:1.05rem}
.primary-nav ul{list-style:none;display:flex;align-items:center;gap:6px;margin:0;padding:0}
.primary-nav a{display:inline-block;padding:10px 12px;border-radius:8px;color:var(--text);font-weight:500;font-size:.95rem}
.primary-nav a:hover{background:var(--primary-50);text-decoration:none;color:var(--primary-600)}
.primary-nav .has-sub{position:relative}
.primary-nav .sub{position:absolute;top:100%;left:0;background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:8px;min-width:220px;box-shadow:var(--shadow-lg);display:none;flex-direction:column;gap:2px;z-index:60}
.primary-nav .has-sub:hover > .sub,.primary-nav .has-sub:focus-within > .sub{display:flex}
.theme-toggle{background:transparent;border:1px solid var(--border);border-radius:8px;width:38px;height:38px;cursor:pointer;font-size:1rem;color:var(--text)}
.theme-toggle:hover{background:var(--primary-50)}
.nav-toggle{display:none;background:transparent;border:1px solid var(--border);border-radius:8px;width:40px;height:40px;cursor:pointer;flex-direction:column;justify-content:center;align-items:center;gap:4px;padding:0}
.nav-toggle span{display:block;width:18px;height:2px;background:var(--text);border-radius:2px}

@media (max-width: 900px){
  .nav-toggle{display:inline-flex}
  .primary-nav{position:fixed;inset:64px 0 auto 0;background:var(--surface);border-bottom:1px solid var(--border);max-height:0;overflow:hidden;transition:max-height .25s ease}
  .primary-nav.open{max-height:90vh;overflow:auto}
  .primary-nav ul{flex-direction:column;align-items:stretch;padding:12px}
  .primary-nav a{padding:12px 14px}
  .primary-nav .sub{position:static;display:flex;box-shadow:none;border:none;padding:0 0 8px 14px;background:transparent}
}

/* Hero */
.hero{padding:72px 0 56px;background:linear-gradient(180deg,var(--primary-50),transparent)}
.hero h1 span{color:var(--primary-600)}
.hero .lede{font-size:1.15rem;margin-bottom:24px}
.hero-cta{display:flex;gap:12px;flex-wrap:wrap}
.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:12px 18px;border-radius:10px;font-weight:600;font-size:.98rem;border:1px solid transparent;cursor:pointer;transition:transform .15s ease, background .15s ease;background:var(--primary);color:#fff}
.btn:hover{background:var(--primary-600);text-decoration:none;transform:translateY(-1px)}
.btn-outline{background:transparent;color:var(--text);border-color:var(--border)}
.btn-outline:hover{background:var(--bg-soft);color:var(--text)}
.btn-ghost{background:transparent;color:var(--primary-600);padding:8px 12px}
.btn-sm{padding:8px 12px;font-size:.88rem}

/* Cards / tools */
.tool-grid{display:grid;gap:18px;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));margin-top:24px}
.tool-card{display:block;padding:22px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-sm);color:var(--text);transition:transform .2s ease, box-shadow .2s ease, border-color .2s ease}
.tool-card:hover{text-decoration:none;transform:translateY(-3px);box-shadow:var(--shadow);border-color:color-mix(in srgb,var(--primary) 40%, var(--border))}
.tool-card h3{margin:0 0 6px;color:var(--text)}
.tool-card p{margin:0 0 10px;color:var(--muted);font-size:.95rem}
.tool-card .arrow{color:var(--primary-600);font-weight:600;font-size:.9rem}

/* Calculator panel */
.calc{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow);padding:24px;margin-top:28px}
.calc h2{margin-top:0}
.calc-row{display:grid;grid-template-columns:1.5fr .8fr .8fr auto;gap:10px;margin-bottom:10px;align-items:end}
.calc-row .field{display:flex;flex-direction:column;gap:4px}
.calc-row label{font-size:.8rem;font-weight:600;color:var(--muted);text-transform:uppercase;letter-spacing:.04em}
input[type=text],input[type=number],select,textarea{width:100%;padding:10px 12px;border:1px solid var(--border);border-radius:10px;background:var(--bg);color:var(--text);font:inherit;transition:border-color .15s ease, box-shadow .15s ease}
input:focus,select:focus,textarea:focus{outline:none;border-color:var(--primary);box-shadow:0 0 0 3px color-mix(in srgb,var(--primary) 22%, transparent)}
.icon-btn{background:transparent;border:1px solid var(--border);border-radius:10px;width:40px;height:40px;cursor:pointer;color:var(--danger);font-weight:700}
.icon-btn:hover{background:#fee2e2}
[data-theme="dark"] .icon-btn:hover{background:#3a1f24}
.calc-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px}
.result{margin-top:20px;padding:18px;border-radius:12px;background:var(--primary-50);border:1px solid color-mix(in srgb,var(--primary) 25%, var(--border));display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap}
.result .big{font-size:1.8rem;font-weight:800;color:var(--primary-600);letter-spacing:-.02em}
.result .label{display:block;font-size:.78rem;text-transform:uppercase;color:var(--muted);letter-spacing:.06em;margin-bottom:4px}
.note{font-size:.88rem;color:var(--muted);margin-top:10px}
.error{color:var(--danger);font-size:.9rem;margin-top:8px}

@media (max-width:700px){
  .calc-row{grid-template-columns:1fr 1fr;}
  .calc-row .field:first-child{grid-column:1/-1}
  .icon-btn{justify-self:end}
}

/* Content */
.prose h2{margin-top:2.2em}
.prose h3{margin-top:1.6em}
.prose ul,.prose ol{padding-left:1.2em}
.prose li{margin-bottom:.4em}
.prose table{width:100%;border-collapse:collapse;margin:1em 0;display:block;overflow-x:auto}
.prose th,.prose td{border:1px solid var(--border);padding:10px 12px;text-align:left;font-size:.95rem;white-space:nowrap}
.prose th{background:var(--bg-soft);font-weight:600}
.callout{background:var(--bg-soft);border-left:4px solid var(--primary);padding:14px 18px;border-radius:8px;margin:18px 0}
.callout.warn{border-left-color:var(--warning);background:color-mix(in srgb,#fef3c7 60%,var(--bg-soft))}
[data-theme="dark"] .callout.warn{background:color-mix(in srgb,#3a2a08 60%,var(--bg-soft))}

/* FAQ */
.faq{display:flex;flex-direction:column;gap:10px;margin-top:18px}
.faq-item{background:var(--surface);border:1px solid var(--border);border-radius:12px;padding:14px 18px;box-shadow:var(--shadow-sm)}
.faq-item summary{cursor:pointer;font-weight:600;list-style:none;display:flex;justify-content:space-between;align-items:center;gap:10px}
.faq-item summary::-webkit-details-marker{display:none}
.faq-item summary::after{content:"+";font-size:1.3rem;color:var(--primary-600);transition:transform .2s ease}
.faq-item[open] summary::after{content:"–"}
.faq-answer{margin-top:10px;color:var(--muted)}

/* Footer */
.site-footer{background:var(--bg-soft);border-top:1px solid var(--border);margin-top:60px;padding:50px 0 24px}
.footer-grid{display:grid;gap:30px;grid-template-columns:1.4fr 1fr 1fr 1fr}
.footer-grid h4{font-size:.85rem;text-transform:uppercase;letter-spacing:.08em;color:var(--muted);margin-bottom:12px}
.footer-grid ul{list-style:none;padding:0;margin:0;display:flex;flex-direction:column;gap:6px}
.footer-grid a{color:var(--text);font-size:.95rem}
.footer-grid a:hover{color:var(--primary-600)}
.footer-brand{margin-bottom:10px}
.footer-bottom{margin-top:30px;padding-top:18px;border-top:1px solid var(--border);font-size:.88rem;color:var(--muted)}
@media (max-width:800px){
  .footer-grid{grid-template-columns:1fr 1fr}
}

/* Back to top */
.back-to-top{position:fixed;right:18px;bottom:18px;width:42px;height:42px;border-radius:50%;border:none;background:var(--primary);color:#fff;font-size:1.2rem;cursor:pointer;opacity:0;transform:translateY(10px);transition:.25s;box-shadow:var(--shadow);z-index:40}
.back-to-top.visible{opacity:1;transform:none}

/* Reveal animations */
.reveal{opacity:0;transform:translateY(14px);transition:opacity .6s ease, transform .6s ease}
.reveal.visible{opacity:1;transform:none}

@media (prefers-reduced-motion: reduce){
  *{animation:none!important;transition:none!important}
  html{scroll-behavior:auto}
}