:root{
  --bg:#f7fafc; --surface:#ffffff; --surface2:#eef4f7; --ink:#12242e; --muted:#4a5f6b;
  --line:#d9e4ea; --blue:#0b5fa5; --blue-d:#084a84; --teal:#0e7c7b; --teal-soft:#e3f2f0;
  --amber:#9a6a00; --amber-bg:#fdf3d7; --red:#b3261e; --red-bg:#fdecea; --green:#146c43; --green-bg:#e6f4ea;
  --radius:14px; --shadow:0 1px 3px rgba(18,36,46,.08),0 6px 18px rgba(18,36,46,.05);
}
@media (prefers-color-scheme: dark){
  :root{ --bg:#0d161c; --surface:#15222b; --surface2:#1b2c38; --ink:#e8f1f5; --muted:#a9bfca;
    --line:#2c4250; --blue:#5aa9e6; --blue-d:#8fc4f0; --teal:#3fc1bd; --teal-soft:#14322f;
    --amber:#f0c35c; --amber-bg:#33290f; --red:#f28b82; --red-bg:#3a1c1a; --green:#7fd6a4; --green-bg:#14301f;
    --shadow:0 1px 3px rgba(0,0,0,.4),0 6px 18px rgba(0,0,0,.3); }
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
@media (prefers-reduced-motion: reduce){ html{scroll-behavior:auto} }
body{margin:0;background:var(--bg);color:var(--ink);font-family:system-ui,-apple-system,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;line-height:1.6;font-size:16px}
a{color:var(--blue)}
a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--teal);outline-offset:2px;border-radius:6px}
.wrap{max-width:1120px;margin:0 auto;padding:0 18px}
/* Header */
header.site{position:sticky;top:0;z-index:50;background:var(--surface);border-bottom:1px solid var(--line)}
.header-in{display:flex;align-items:center;gap:14px;padding:10px 0;flex-wrap:wrap}
.logo{font-weight:800;font-size:1.3rem;color:var(--ink);text-decoration:none;letter-spacing:-.02em}
.logo span{color:var(--teal)}
.logo small{display:block;font-size:.68rem;font-weight:600;color:var(--muted);letter-spacing:.04em;text-transform:uppercase}
nav.main{display:flex;gap:2px;flex-wrap:wrap;margin-left:auto}
nav.main a{color:var(--ink);text-decoration:none;font-size:.92rem;font-weight:600;padding:7px 10px;border-radius:8px}
nav.main a:hover{background:var(--surface2)}
nav.main a[aria-current="page"]{background:var(--teal-soft);color:var(--teal)}
/* Hero */
.hero{padding:44px 0 30px}
.hero h1{font-size:2.35rem;line-height:1.15;margin:0 0 12px;letter-spacing:-.02em;max-width:16em}
.hero p.lede{font-size:1.13rem;color:var(--muted);max-width:38em;margin:0 0 22px}
.cta-row{display:flex;gap:12px;flex-wrap:wrap}
.btn{display:inline-block;background:var(--blue);color:#fff;text-decoration:none;font-weight:700;padding:12px 22px;border-radius:10px;border:2px solid var(--blue);cursor:pointer;font-size:1rem;font-family:inherit}
.btn:hover{background:var(--blue-d);border-color:var(--blue-d)}
.btn.ghost{background:transparent;color:var(--blue)}
.btn.ghost:hover{background:var(--surface2)}
.btn.small{padding:8px 14px;font-size:.9rem}
.btn.danger{background:transparent;color:var(--red);border-color:var(--line)}
.btn.danger:hover{background:var(--red-bg)}
.trust{display:flex;gap:18px;flex-wrap:wrap;margin-top:22px;color:var(--muted);font-size:.9rem}
.trust b{color:var(--ink)}
/* Cards grid */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(300px,1fr));gap:16px;margin:10px 0 8px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:8px}
.card h3{margin:0;font-size:1.12rem}
.card p{margin:0;color:var(--muted);font-size:.95rem;flex:1}
.card a.open{font-weight:700;text-decoration:none}
.card a.open:hover{text-decoration:underline}
.card .tag{align-self:flex-start;font-size:.72rem;font-weight:700;letter-spacing:.05em;text-transform:uppercase;color:var(--teal);background:var(--teal-soft);padding:3px 9px;border-radius:99px}
section.block{padding:30px 0}
h2.sec{font-size:1.55rem;margin:0 0 6px;letter-spacing:-.01em}
p.sec-sub{color:var(--muted);margin:0 0 18px;max-width:44em}
/* Views */
.view{display:none}
.view.active{display:block}
.crumbs{font-size:.87rem;color:var(--muted);padding:18px 0 0}
.crumbs a{color:var(--muted)}
.page-head{padding:10px 0 4px}
.page-head h1{font-size:2rem;line-height:1.2;margin:6px 0 8px;letter-spacing:-.02em}
.page-head p.lede{color:var(--muted);font-size:1.05rem;max-width:44em;margin:0}
/* Calculator */
.calc{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);box-shadow:var(--shadow);padding:22px;margin:20px 0}
.calc h2{margin-top:0;font-size:1.25rem}
label{display:block;font-weight:600;font-size:.9rem;margin-bottom:5px}
input[type=text],input[type=number],select{width:100%;padding:10px 11px;border:1.5px solid var(--line);border-radius:9px;background:var(--surface);color:var(--ink);font-size:1rem;font-family:inherit}
input:focus,select:focus{border-color:var(--teal)}
.field{margin-bottom:14px}
.hint{font-size:.83rem;color:var(--muted);margin-top:4px}
.row-head,.subj-row{display:grid;grid-template-columns:1fr 92px 108px 40px;gap:8px;align-items:end}
.row-head{font-size:.8rem;font-weight:700;color:var(--muted);margin-bottom:6px}
.subj-row{margin-bottom:8px}
.subj-row .rm{align-self:center}
.rm{width:36px;height:40px;border:1.5px solid var(--line);background:var(--surface);color:var(--red);border-radius:9px;font-size:1.05rem;cursor:pointer}
.rm:hover{background:var(--red-bg)}
.gpa-row{display:grid;grid-template-columns:1fr 108px 40px;gap:8px;align-items:end;margin-bottom:8px}
.two-col{display:grid;grid-template-columns:1fr 1fr;gap:14px}
.result{border-radius:12px;padding:18px 20px;margin-top:18px;background:var(--teal-soft);border:1px solid var(--line)}
.result .big{font-size:2.1rem;font-weight:800;line-height:1.1;letter-spacing:-.02em}
.result .stats{display:flex;gap:22px;flex-wrap:wrap;margin-top:8px;font-size:.93rem}
.result .stats b{display:block;font-size:1.05rem}
.result.warn{background:var(--amber-bg)}
.result.bad{background:var(--red-bg)}
.result.good{background:var(--green-bg)}
.note{border:1px solid var(--amber);background:var(--amber-bg);border-radius:12px;padding:14px 16px;font-size:.93rem;margin:16px 0}
.note.blue{border-color:var(--blue);background:var(--surface2)}
table.data{width:100%;border-collapse:collapse;font-size:.93rem;margin:10px 0}
table.data th,table.data td{padding:8px 10px;border-bottom:1px solid var(--line);text-align:left}
table.data th{font-size:.8rem;text-transform:uppercase;letter-spacing:.04em;color:var(--muted)}
table.data td.num,table.data th.num{text-align:right}
.scroll-x{overflow-x:auto}
/* Content */
.content{max-width:820px}
.content h2{font-size:1.45rem;margin:30px 0 8px}
.content h3{font-size:1.12rem;margin:20px 0 6px}
.content p,.content li{color:var(--ink)}
.content p{color:#22343f}
@media (prefers-color-scheme: dark){ .content p{color:var(--ink)} }
.formula{background:var(--surface2);border:1px solid var(--line);border-radius:10px;padding:14px 16px;font-family:ui-monospace,SFMono-Regular,Menlo,Consolas,monospace;font-size:.95rem;overflow-x:auto;white-space:nowrap}
.example{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:16px 18px}
details.faq{border:1px solid var(--line);border-radius:10px;background:var(--surface);margin-bottom:10px}
details.faq summary{cursor:pointer;font-weight:700;padding:14px 16px;list-style:none}
details.faq summary::-webkit-details-marker{display:none}
details.faq summary::after{content:"+";float:right;color:var(--teal);font-size:1.2rem}
details.faq[open ] summary::after{content:"–"}
details.faq .a{padding:0 16px 14px;color:var(--muted)}
.related{display:flex;gap:10px;flex-wrap:wrap;margin:14px 0}
.related a{background:var(--surface);border:1px solid var(--line);border-radius:99px;padding:7px 14px;text-decoration:none;font-size:.9rem;font-weight:600}
.related a:hover{border-color:var(--teal)}
/* Footer */
footer.site{border-top:1px solid var(--line);background:var(--surface);margin-top:44px;padding:30px 0 38px}
footer.site .cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:22px}
footer.site h4{margin:0 0 10px;font-size:.95rem}
footer.site ul{list-style:none;margin:0;padding:0}
footer.site li{margin-bottom:7px}
footer.site a{color:var(--muted);text-decoration:none;font-size:.92rem}
footer.site a:hover{color:var(--blue);text-decoration:underline}
footer.site .fine{color:var(--muted);font-size:.85rem;margin-top:24px;max-width:60em}
.sr-only{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap}
@media (max-width:640px){
  .hero h1{font-size:1.85rem}
  .page-head h1{font-size:1.6rem}
  .row-head{display:none}
  .subj-row{grid-template-columns:1fr 76px 92px 38px}
  .two-col{grid-template-columns:1fr}
  nav.main{margin-left:0}
  .calc{padding:16px}
}