:root{--ink:#132238;--blue:#0b5cab;--deep:#073b72;--sky:#eaf4ff;--paper:#fff;--muted:#627083;--line:#dce5ef;--accent:#f2b134}
*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;font-family:Arial,Helvetica,sans-serif;color:var(--ink);background:var(--paper);line-height:1.6}
.container{width:min(1120px,92%);margin:auto}.site-header{position:sticky;top:0;z-index:10;background:rgba(255,255,255,.96);border-bottom:1px solid var(--line)}
.nav-wrap{min-height:74px;display:flex;align-items:center;justify-content:space-between;gap:24px}.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink)}
.brand span:last-child{display:flex;flex-direction:column;line-height:1.05}.brand small{color:var(--muted);margin-top:4px}.logo{display:grid;place-items:center;width:44px;height:44px;border-radius:12px;background:var(--blue);color:white;font-weight:800}
nav{display:flex;gap:20px;flex-wrap:wrap}nav a{color:var(--ink);text-decoration:none;font-size:.94rem;font-weight:700}nav a:hover{color:var(--blue)}
.hero{background:linear-gradient(135deg,#f5faff 0%,#e8f3ff 55%,#fff8e8 100%);padding:92px 0}.hero-grid{display:grid;grid-template-columns:1.25fr .75fr;gap:56px;align-items:center}
.eyebrow{font-size:.78rem;font-weight:800;letter-spacing:.16em;color:var(--blue);margin:0 0 10px}.hero h1{font-size:clamp(2.6rem,6vw,5.2rem);line-height:.98;margin:0 0 24px;letter-spacing:-.05em}
.lead{font-size:1.35rem;font-weight:700;max-width:720px}.actions{display:flex;gap:12px;margin-top:28px;flex-wrap:wrap}.btn{display:inline-block;padding:12px 18px;border-radius:10px;text-decoration:none;font-weight:800}
.primary{background:var(--blue);color:white}.secondary{border:1px solid var(--blue);color:var(--blue);background:white}.math-card{background:var(--deep);color:white;border-radius:24px;padding:34px;box-shadow:0 24px 50px rgba(7,59,114,.18)}
.formula{padding:14px 0;border-bottom:1px solid rgba(255,255,255,.18);font-family:Georgia,serif;font-size:1.4rem}.math-card p{color:#cfe5ff;margin-bottom:0}
.section{padding:82px 0}.alt{background:#f7f9fc}.section h2{font-size:clamp(2rem,4vw,3.2rem);line-height:1.05;margin:0 0 20px}.section-intro{max-width:800px;color:var(--muted);font-size:1.12rem}
.cards{display:grid;gap:22px;margin-top:34px}.three{grid-template-columns:repeat(3,1fr)}.card{background:white;border:1px solid var(--line);border-radius:18px;padding:28px;box-shadow:0 10px 25px rgba(19,34,56,.04)}
.icon{display:inline-grid;place-items:center;min-width:48px;height:48px;padding:0 10px;border-radius:12px;background:var(--sky);color:var(--blue);font-weight:900}.card h3{margin:18px 0 8px}.card p{color:var(--muted)}
.tag{font-size:.72rem;font-weight:900;letter-spacing:.13em;color:var(--blue)}.resource a{color:var(--blue);font-weight:800;text-decoration:none}
.topic-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px;margin-top:30px}.topic-grid div{border:1px solid var(--line);border-radius:12px;padding:20px;font-weight:800;background:white}
.person{text-align:center}.avatar{width:72px;height:72px;margin:auto;display:grid;place-items:center;border-radius:50%;background:var(--blue);color:white;font-weight:900;font-size:1.2rem}.person p{color:var(--blue);font-weight:800}
.contact{text-align:center;background:var(--deep);color:white}.contact .eyebrow{color:#8dc7ff}.contact p{max-width:720px;margin:0 auto 26px;color:#d7e9fb}
footer{padding:30px 0;background:#071f37;color:#d7e2ec}.footer-wrap{display:flex;justify-content:space-between;gap:20px;align-items:center}.footer-wrap span{color:#9eb2c4}
@media(max-width:820px){.nav-wrap{align-items:flex-start;padding:14px 0;flex-direction:column}nav{gap:12px}.hero{padding:62px 0}.hero-grid,.three,.topic-grid{grid-template-columns:1fr}.footer-wrap{flex-direction:column;align-items:flex-start}}