:root{--indigo:#0a3d62;--p:#0e6b8f;--p2:#1b8fb5;--mint:#3ce3c4;--ink:#12303d;--ink2:#4c6a78;--bg:#f1f7fa;--card:#fff;--line:#d3e3ea;--r:20px;--ease:cubic-bezier(.22,1,.36,1)}
@media(prefers-color-scheme:dark){:root{--ink:#e6f3f8;--ink2:#9fbfcc;--bg:#0b1a22;--card:#12262f;--line:#27434f}}
*{box-sizing:border-box}html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font:16px/1.95 Vazirmatn,Tahoma,sans-serif}
a{color:var(--p2)}h1,h2,h3{line-height:1.5;margin:0 0 .5em}h1{font-size:clamp(1.6rem,5vw,2.3rem)}h2{font-size:1.4rem}h3{font-size:1.1rem}
.wrap{max-width:1000px;margin:0 auto;padding:0 18px}
.nav{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:10px 18px;background:linear-gradient(100deg,#0a3d62,#5a2fd0);color:#fff;position:sticky;top:0;z-index:20}
.nav a{color:#fff;text-decoration:none}.brand{display:flex;align-items:center;gap:10px}.brand img{border-radius:9px}
.nav nav{display:flex;gap:6px;align-items:center;flex-wrap:wrap}.nav nav a{padding:5px 12px;border-radius:10px;opacity:.9}.nav nav a:hover{background:#fff2}.nav .cta{background:var(--mint);color:#0b3d33;font-weight:500}
.hero{background:radial-gradient(120% 100% at 75% 0,#1b8fb5,#0e6b8f 45%,#0a3d62);color:#fff;text-align:center;padding:56px 0 64px}
.hero h1{max-width:20ch;margin:16px auto 10px}.lead{max-width:56ch;margin:0 auto 22px;opacity:.92;font-size:1.08rem}.logo{border-radius:24px;box-shadow:0 16px 44px #0006}
.cta-row{display:flex;gap:10px;justify-content:center;flex-wrap:wrap;margin:0}.small{opacity:.75;font-size:.88rem;margin:12px 0 0}
.btn{display:inline-block;padding:12px 24px;border-radius:15px;background:#fff;color:var(--p);text-decoration:none;font-weight:500;transition:transform .25s var(--ease),box-shadow .25s}
.btn:hover{transform:translateY(-2px);box-shadow:0 10px 24px #0003}.btn.ghost{background:#ffffff22;color:#fff;box-shadow:inset 0 0 0 1px #fff6}
.block{padding-top:44px;padding-bottom:6px}.cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:14px;margin:14px 0}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--r);padding:18px;box-shadow:0 8px 26px #0e6b8f12}.card p{margin:.3em 0 0}.card a{text-decoration:none}
.cat{margin:22px 0 8px;color:var(--ink2);font-size:1rem;font-weight:500}
.chips{list-style:none;padding:0;margin:0;display:flex;flex-wrap:wrap;gap:8px}.chips li{background:var(--card);border:1px solid var(--line);border-radius:99px;padding:3px 14px}.chips a{text-decoration:none}
.tag{display:inline-block;background:#e0faf4;color:#0b6b57;border-radius:99px;padding:0 10px;font-size:.78rem}
.muted,.meta,.crumb{color:var(--ink2);font-size:.9rem}.crumb a{text-decoration:none}
details{background:var(--card);border:1px solid var(--line);border-radius:16px;padding:12px 16px;margin:8px 0}summary{cursor:pointer;font-weight:500}details p{margin:.6em 0 0}
.article{padding-top:30px;padding-bottom:40px;max-width:760px}.prose p{margin:0 0 14px}
.prose .disp{margin:12px 0 16px;padding:10px 6px;overflow-x:auto;background:var(--card);border:1px solid var(--line);border-radius:14px;text-align:center;direction:ltr}
.prose .katex{direction:ltr;unicode-bidi:isolate}.prose b{color:var(--p2)}
.promo{margin-top:30px;background:linear-gradient(150deg,#0e6b8f,#1b8fb5);color:#fff;border:0}.promo .btn{background:#fff;color:var(--p)}.promo h2{font-size:1.2rem}
.lead2{color:var(--ink2);max-width:60ch}
footer{margin-top:50px;padding:30px 0;border-top:1px solid var(--line);color:var(--ink2);font-size:.92rem;text-align:center}footer p{margin:.3em 0}
@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}