:root{--ink:#122639;--muted:#77899b;--blue:#2672ec;--line:#e2e9f0}*{box-sizing:border-box}
body{margin:0;background:#f5f8fc;font-family:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;color:var(--ink)}
header{background:#0b2035;color:#fff;padding:23px 20px}header .content{display:flex;align-items:center;justify-content:space-between;max-width:1060px;margin:auto}
.brand{font-size:17px;letter-spacing:.16em;font-weight:850}header span{font-size:12px;color:#b4c5d6}
main{max-width:1060px;margin:auto;padding:70px 22px}small.kicker{color:#276bd9;font-weight:800;letter-spacing:.17em}
h1{font-size:clamp(32px,5vw,56px);letter-spacing:-.05em;margin:12px 0}p{line-height:1.65;color:#6e8194}
.lead{max-width:690px;font-size:17px}#detected{display:inline-block;border-radius:100px;background:#e4f0ff;color:#2364ba;padding:10px 16px;font-size:13px;font-weight:750;margin:15px 0 32px}
.platforms{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:15px}.platform{background:white;border:1px solid var(--line);border-radius:18px;padding:26px 22px;box-shadow:0 7px 28px #22416909;min-height:280px}
.platform.recommended{border:2px solid #2a79ef;box-shadow:0 14px 38px #276fe326}
.icon{font-size:39px}.platform h2{font-size:19px;margin:19px 0 9px}.platform p{font-size:13px;min-height:66px}.label{border-radius:7px;background:#edf3fa;color:#607b94;padding:7px 10px;font-size:11px;font-weight:700;display:inline-block}
.notice{margin-top:32px;padding:25px;border-radius:17px;background:#eaf3ff;border:1px solid #d0e3fa}.notice strong{font-size:16px}.notice p{margin-bottom:0}
.guide{margin:33px 0}.guide h2{font-size:23px}.steps{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.step{background:white;padding:21px;border-radius:15px;border:1px solid var(--line)}.step b{color:#2771e3;font-size:12px}.step h3{font-size:16px;margin:12px 0 4px}.step p{font-size:13px;margin:0}.footer{padding:30px 15px;text-align:center;color:#8294a6;font-size:12px;border-top:1px solid var(--line)}
a{color:#2373e9;text-decoration:none}
@media(max-width:900px){.platforms{grid-template-columns:repeat(2,minmax(0,1fr))}.steps{grid-template-columns:1fr}}
@media(max-width:520px){main{padding:45px 17px}.platforms{grid-template-columns:1fr}.platform{min-height:0}.platform p{min-height:0}}