:root{--bg:#f7f9fb;--fg:#14212b;--muted:#5b6b78;--brand:#0b6e74;--brand2:#0f8b8d;--accent:#f2a541;--ok:#1f8a4c;--bad:#c0392b;--card:#fff;--line:#dde4ea;--radius:12px}
button,input,select{font:inherit}
*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}
body{margin:0;font:16px/1.55 system-ui,-apple-system,"Segoe UI",Roboto,Arial,sans-serif;background:var(--bg);color:var(--fg)}
a{color:var(--brand)}img{max-width:100%}
.wrap{max-width:980px;margin:0 auto;padding:0 18px}
header.site{background:#fff;border-bottom:1px solid var(--line);position:sticky;top:0;z-index:5}
header.site .wrap{display:flex;align-items:center;gap:14px;height:58px}
.logo{font-weight:800;color:var(--fg);text-decoration:none;font-size:18px}.logo span{color:var(--brand)}
nav.main{display:flex;gap:14px;margin-left:auto;align-items:center;flex-wrap:wrap}nav.main a{text-decoration:none;color:var(--fg);font-size:15px}
.lang{border:1px solid var(--line);background:#fff;border-radius:999px;padding:4px 10px;cursor:pointer;font-weight:600}
.btn{display:inline-block;background:var(--brand);color:#fff;border:0;border-radius:10px;padding:12px 18px;font-weight:700;text-decoration:none;cursor:pointer;font-size:16px}
.btn:hover{background:var(--brand2)}.btn.secondary{background:#fff;color:var(--brand);border:2px solid var(--brand)}.btn.small{padding:7px 12px;font-size:14px}
.btn[disabled]{opacity:.5;cursor:not-allowed}
.hero{padding:56px 0 34px;background:linear-gradient(160deg,#e6f4f4,#f7f9fb)}
.hero h1{font-size:40px;line-height:1.15;margin:0 0 12px}.hero p.lead{font-size:19px;color:var(--muted);max-width:640px}
.stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(170px,1fr));gap:12px;margin:24px 0}
.stat{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:14px}.stat b{font-size:26px;display:block;color:var(--brand)}
.stat small{color:var(--muted)}
section{padding:28px 0}h2{font-size:26px;margin:0 0 12px}
.grid3{display:grid;grid-template-columns:repeat(auto-fit,minmax(230px,1fr));gap:14px}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:18px}
.price{font-size:44px;font-weight:800}.price small{font-size:16px;color:var(--muted);font-weight:500}
ul.check{list-style:none;padding:0}ul.check li{padding:4px 0 4px 26px;position:relative}ul.check li:before{content:"✓";position:absolute;left:0;color:var(--ok);font-weight:800}
.disclaimer{font-size:13px;color:var(--muted);border-top:1px solid var(--line);padding:18px 0;margin-top:30px}
footer.site{background:#fff;border-top:1px solid var(--line);margin-top:40px}footer.site .wrap{padding:22px 18px;font-size:14px;color:var(--muted)}
footer.site a{margin-right:12px}
.draft-banner{background:#fff4e0;border-bottom:1px solid #f2d39b;color:#7a4b00;font-size:13px;text-align:center;padding:6px 10px}
/* exam */
.exam-top{display:flex;justify-content:space-between;align-items:center;gap:10px;flex-wrap:wrap;margin:18px 0}
.timer{font-variant-numeric:tabular-nums;font-weight:800;font-size:20px;background:#fff;border:1px solid var(--line);border-radius:10px;padding:6px 12px}
.progress{height:8px;background:var(--line);border-radius:99px;overflow:hidden;flex:1;min-width:140px}.progress i{display:block;height:100%;background:var(--brand)}
.q{background:#fff;border:1px solid var(--line);border-radius:var(--radius);padding:20px}
.q .meta{font-size:13px;color:var(--muted);margin-bottom:8px}
.q h3{font-size:19px;margin:0 0 14px;line-height:1.4}
.choice{display:flex;gap:10px;align-items:flex-start;width:100%;text-align:left;background:#fff;border:2px solid var(--line);border-radius:10px;padding:12px;margin:8px 0;cursor:pointer;font-size:16px;color:var(--fg)}
.choice:hover{border-color:var(--brand2)}.choice.sel{border-color:var(--brand);background:#e9f5f5}
.choice.right{border-color:var(--ok);background:#e8f6ee}.choice.wrong{border-color:var(--bad);background:#fbeceb}
.choice b{min-width:22px}
.exam-nav{display:flex;gap:10px;justify-content:space-between;margin-top:16px;flex-wrap:wrap}
.flag{background:none;border:1px dashed var(--accent);color:#8a5a00;border-radius:8px;padding:6px 10px;cursor:pointer}.flag.on{background:#fff4e0}
.palette{display:flex;flex-wrap:wrap;gap:5px;margin-top:16px}.palette button{width:34px;height:30px;border:1px solid var(--line);background:#fff;border-radius:6px;cursor:pointer;font-size:12px}
.palette .ans{background:#d7eeee}.palette .cur{outline:2px solid var(--brand)}.palette .fl{border-color:var(--accent);border-width:2px}
.expl{margin-top:12px;background:#f2f7f9;border-left:4px solid var(--brand);padding:10px 14px;border-radius:6px}
.expl .es{color:#2e4756;margin-top:6px;font-style:italic}
/* results */
.bars .row{display:grid;grid-template-columns:minmax(150px,260px) 1fr 52px;gap:10px;align-items:center;margin:8px 0}
.bar{position:relative;height:18px;background:var(--line);border-radius:99px;overflow:hidden}.bar i{display:block;height:100%;background:var(--brand)}
.bar i.low{background:var(--bad)}.bar i.mid{background:var(--accent)}
.bar .target{position:absolute;left:80%;top:-3px;bottom:-3px;border-left:2px dashed var(--fg)}
.big-score{font-size:56px;font-weight:900;color:var(--brand)}
.notice{background:#fff4e0;border:1px solid #f2d39b;border-radius:10px;padding:12px 14px;font-size:14px}
.err{color:var(--bad)}.okc{color:var(--ok)}
input[type=text]{width:100%;padding:12px;border:1px solid var(--line);border-radius:10px;font-size:16px}
/* study page */
article.study h1{font-size:32px;line-height:1.2}.tldr{background:#e9f5f5;border:1px solid #bfe1e1;border-radius:var(--radius);padding:14px 18px}
.tldr li{margin:4px 0}.src{font-size:12px;color:var(--muted)}
.es-summary{background:#fff;border:1px dashed var(--brand);border-radius:var(--radius);padding:14px 18px}
details{background:#fff;border:1px solid var(--line);border-radius:10px;padding:10px 14px;margin:8px 0}summary{cursor:pointer;font-weight:600}
.flash{perspective:1000px;max-width:520px;margin:20px auto}.flash .inner{background:#fff;border:2px solid var(--brand);border-radius:16px;min-height:220px;display:flex;align-items:center;justify-content:center;padding:24px;text-align:center;font-size:20px;cursor:pointer}
.flash .back{font-size:17px}.flash .back .es{color:#2e4756;font-style:italic;margin-top:10px;font-size:15px}
.hide{display:none!important}
@media(max-width:640px){.hero h1{font-size:30px}nav.main a.hide-sm{display:none}.bars .row{grid-template-columns:1fr 1fr 44px}}