:root{
  --ground:#F6F7FA; --surface:#FFFFFF; --raise:#EDF0F5;
  --ink:#161A21; --body:#2C3340; --muted:#626C7C; --faint:#8F99A8;
  --line:#DEE3EB; --line-2:#C8D0DC;
  --accent:#C2410C; --accent-bg:#FBEEE6;
  --gA:#136E3F; --gB:#1D51AD; --gC:#9A5C08; --gD:#A72424;
  --gA-bg:#E4F1E9; --gB-bg:#E3EBFA; --gC-bg:#F7EDDC; --gD-bg:#F8E5E5;
  --shadow:0 1px 2px rgba(20,26,36,.05),0 8px 24px -16px rgba(20,26,36,.28);
}
@media (prefers-color-scheme:dark){
  :root{
    --ground:#0E1218; --surface:#161C25; --raise:#1E2631;
    --ink:#E7EBF2; --body:#C3CBD8; --muted:#8F9AAA; --faint:#6C7787;
    --line:#252E3A; --line-2:#354050;
    --accent:#F0875A; --accent-bg:#2A1A12;
    --gA:#5CC48B; --gB:#7CA6F0; --gC:#E0A752; --gD:#EC8080;
    --gA-bg:#14261C; --gB-bg:#161F33; --gC-bg:#2A2114; --gD-bg:#2B1717;
  }
}
*{box-sizing:border-box}
html{-webkit-text-size-adjust:100%}
body{margin:0;background:var(--ground);color:var(--body);font:17px/1.6 Charter,"Bitstream Charter","Sitka Text",Cambria,Georgia,serif;-webkit-font-smoothing:antialiased}
a{color:var(--ink);text-decoration-color:var(--accent);text-underline-offset:3px}
a:hover{color:var(--accent)}
img{max-width:100%;height:auto;display:block}
.wrap{max-width:980px;margin:0 auto;padding:0 20px}
.narrow{max-width:680px}
h1,h2,h3{font-family:system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--ink);line-height:1.15;letter-spacing:-.015em;margin:0 0 .4em}
h1{font-size:clamp(2rem,5.2vw,3.1rem);font-weight:700}
h2{font-size:1.55rem;font-weight:700;margin-top:0}
h3{font-size:1.12rem;font-weight:650}
p{margin:0 0 1em}
.kicker{font:600 .74rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;letter-spacing:.16em;text-transform:uppercase;color:var(--accent);margin-bottom:14px}
.stand{font-size:1.2rem;line-height:1.55;color:var(--body);max-width:40em}
.muted{color:var(--muted)}
.small{font-size:.9rem}
.mono{font-family:ui-monospace,"SF Mono",Menlo,Consolas,"Liberation Mono",monospace;font-size:.86em}

.bar{border-bottom:1px solid var(--line);background:var(--surface)}
.bar .wrap{display:flex;justify-content:space-between;align-items:center;gap:16px;padding-top:14px;padding-bottom:14px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;font:700 1.02rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--ink);letter-spacing:-.01em}
.brand .mk{width:26px;height:26px;border-radius:6px;background:var(--ink);color:var(--ground);display:grid;place-items:center;font:800 .82rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
.bar nav{display:flex;gap:18px;font:500 .9rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
.bar nav a{text-decoration:none;color:var(--muted)}
.bar nav a:hover{color:var(--ink)}

section{padding:56px 0}
section + section{border-top:1px solid var(--line)}
.hero{padding:72px 0 56px}

.grades{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:12px;margin-top:28px}
.grade{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:14px 16px;box-shadow:var(--shadow)}
.grade b{display:inline-grid;place-items:center;width:28px;height:28px;border-radius:6px;font:800 .9rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;margin-bottom:8px}
.grade p{margin:0;font-size:.95rem;line-height:1.45}
.gA b{background:var(--gA-bg);color:var(--gA)} .gB b{background:var(--gB-bg);color:var(--gB)}
.gC b{background:var(--gC-bg);color:var(--gC)} .gD b{background:var(--gD-bg);color:var(--gD)}

.book{display:grid;grid-template-columns:minmax(0,230px) 1fr;gap:36px;align-items:start}
.book img{border-radius:4px;box-shadow:0 18px 40px -18px rgba(0,0,0,.55)}
@media (max-width:640px){.book{grid-template-columns:1fr} .book img{max-width:190px}}
.facts{display:flex;flex-wrap:wrap;gap:8px 22px;margin:4px 0 18px;font:500 .88rem/1.3 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--muted)}
.facts b{color:var(--ink)}

.btn{display:inline-block;font:600 .98rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;padding:14px 20px;border-radius:8px;background:var(--ink);color:var(--ground);text-decoration:none;border:0;cursor:pointer}
.btn:hover{color:var(--ground);background:var(--accent)}
.btn.ghost{background:transparent;color:var(--ink);box-shadow:inset 0 0 0 1.5px var(--line-2)}
.btn.ghost:hover{box-shadow:inset 0 0 0 1.5px var(--accent);color:var(--accent)}
.pill{display:inline-block;font:600 .8rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;padding:8px 12px;border-radius:99px;background:var(--raise);color:var(--muted)}
.actions{display:flex;flex-wrap:wrap;gap:12px;align-items:center}

.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(260px,1fr));gap:16px}
.card{background:var(--surface);border:1px solid var(--line);border-radius:12px;padding:22px 22px 18px;box-shadow:var(--shadow)}
.card p{font-size:.98rem}

.signup{background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:24px;box-shadow:var(--shadow);margin:28px 0}
.signup label{display:block;font:600 .9rem/1.2 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--ink);margin-bottom:8px}
.signup .row{display:flex;gap:10px;flex-wrap:wrap}
.signup input{flex:1 1 220px;min-width:0;font:1rem/1.2 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;padding:13px 14px;border-radius:8px;border:1.5px solid var(--line-2);background:var(--ground);color:var(--ink)}
.signup input:focus{outline:none;border-color:var(--accent)}
.signup .fine{font-size:.86rem;color:var(--muted);margin:12px 0 0;line-height:1.45}
.signup .msg{margin:14px 0 0;padding:12px 14px;border-radius:8px;background:var(--accent-bg);color:var(--ink);font-size:.95rem}

ol.inside{list-style:none;padding:0;margin:20px 0;counter-reset:i}
ol.inside li{counter-increment:i;display:grid;grid-template-columns:34px 1fr;gap:12px;padding:14px 0;border-top:1px solid var(--line)}
ol.inside li:before{content:counter(i);width:28px;height:28px;border-radius:50%;background:var(--ink);color:var(--ground);display:grid;place-items:center;font:700 .85rem/1 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif}
ol.inside b{color:var(--ink)}
.preview{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin:8px 0 6px}
.preview img{border:1px solid var(--line);border-radius:4px;background:#fff}
.warn{border-left:3px solid var(--gD);background:var(--gD-bg);padding:14px 16px;border-radius:0 8px 8px 0;font-size:.95rem;margin:24px 0}
.warn b{color:var(--ink)}

.prose h2{font-size:1.25rem;margin-top:1.8em}
.prose ul{padding-left:1.2em}
.prose li{margin-bottom:.4em}

footer.site{border-top:1px solid var(--line);padding:32px 0 48px;font:.88rem/1.55 system-ui,-apple-system,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif;color:var(--muted)}
footer.site .wrap{display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px 28px}
footer.site a{color:var(--muted)}