*{box-sizing:border-box}body{margin:0;font:17px/1.55 -apple-system,system-ui,"Segoe UI",Roboto,sans-serif;background:#fbf7f1;color:#2b2b2b}
main{max-width:680px;margin:0 auto;padding:14px 14px 60px}h1{font-size:1.45rem;margin:.2em 0}h2{font-size:1.3rem}h3{color:#2f7a6b;margin-top:1.4em}
.hero{background:linear-gradient(135deg,#2f7a6b,#4f9c8a);color:#fff;border-radius:18px;padding:18px}.hero p{margin:.4em 0}
.bar{height:10px;background:#e7e0d6;border-radius:8px;overflow:hidden;margin:8px 0}.hero .bar{background:#ffffff44}.bar div{height:100%;background:#f2b544}
.small{font-size:.85rem;opacity:.85}.center{text-align:center}
.cards{display:flex;flex-direction:column;gap:10px;margin-top:14px}.card{display:flex;gap:12px;align-items:center;background:#fff;border-radius:16px;padding:14px;text-decoration:none;color:inherit;box-shadow:0 1px 4px #0001;min-height:72px}
.card .ic{font-size:1.9rem}.card small{display:block;opacity:.75}.card .prog{color:#2f7a6b;opacity:1;font-weight:600}.card.mock{background:#fff4dc}
.back{display:inline-block;padding:8px 0;color:#2f7a6b;text-decoration:none;font-weight:600}
.tabs{display:flex;gap:8px;margin:8px 0 14px}.tabs a{flex:1;text-align:center;padding:12px;border-radius:12px;background:#ece5da;text-decoration:none;color:inherit;font-weight:600}.tabs a.on{background:#2f7a6b;color:#fff}
.lesson{background:#fff;border-radius:16px;padding:6px 16px 14px;box-shadow:0 1px 4px #0001}
.ex{background:#eef6f3;border-left:4px solid #2f7a6b;padding:10px 12px;border-radius:8px;margin:10px 0;font-family:ui-monospace,Menlo,monospace;font-size:.93rem}.ex.big{font-size:1.1rem;text-align:center;font-weight:700}
.tip{background:#fff4dc;border-radius:10px;padding:10px 12px;margin:10px 0}s{color:#c0392b}
table.facts{width:100%;border-collapse:collapse;font-size:.92rem}.facts td{border-bottom:1px solid #eee;padding:6px 4px;vertical-align:top}.facts td:first-child{font-weight:700;white-space:nowrap;padding-right:10px}
.btn{display:block;width:100%;padding:15px;border-radius:14px;border:0;font-size:1.05rem;font-weight:700;margin:10px 0;text-align:center;text-decoration:none;background:#ece5da;color:#2b2b2b;cursor:pointer}
.btn.primary{background:#2f7a6b;color:#fff}.btn:disabled{opacity:.45}.link{background:none;border:0;color:#2f7a6b;text-decoration:underline;font-size:.9rem;padding:10px}
#prob{background:#fff;border-radius:16px;padding:16px;box-shadow:0 1px 4px #0001}.q{font-size:1.08rem;font-weight:600;margin-bottom:12px}
.ansrow{display:flex;gap:8px;align-items:center}.ansrow input{flex:1;font-size:1.3rem;padding:13px;border:2px solid #cfc6b8;border-radius:12px;min-width:0}.ansrow input:focus{outline:none;border-color:#2f7a6b}.unit{font-weight:700;color:#555}
.choices{display:flex;flex-direction:column;gap:8px}.ch{text-align:left;padding:14px;border-radius:12px;border:2px solid #e2dacd;background:#fff;font-size:1rem;cursor:pointer;color:inherit}
.ch.sel{border-color:#2f7a6b;background:#eef6f3}.ch.right{border-color:#2e9e57;background:#e6f6ea}.ch.wrong{border-color:#c0392b;background:#fdeceb}
.ok,.bad,.warn,.why{padding:10px 12px;border-radius:10px;margin:10px 0}.ok{background:#e6f6ea}.bad{background:#fdeceb}.warn{background:#fff4dc}.why{background:#f1effa}.ok.big{font-size:1.1rem;font-weight:700}
.step{background:#eef6f3;padding:8px 10px;border-radius:8px;margin:6px 0;font-size:.95rem}details{margin-top:8px}summary{cursor:pointer;font-weight:600;color:#2f7a6b;padding:6px 0}
.streak{background:#fff;border-radius:12px;padding:10px 14px;margin-bottom:10px;color:#2f7a6b}
.mockbar{display:flex;justify-content:space-between;font-weight:700}.score{font-size:2.4rem;font-weight:800;text-align:center;color:#2f7a6b}
.rev{background:#fff;border-radius:12px;padding:12px;margin:10px 0;border-left:5px solid #2e9e57}.rev.r-bad{border-left-color:#c0392b}