:root{--bg:#f4f6fb;--card:#fff;--ink:#1d2433;--mut:#667;--pri:#4f46e5;--ok:#16a34a;--bad:#dc2626;--bd:#e3e7f0}
*{box-sizing:border-box}
body{margin:0;font-family:system-ui,Segoe UI,Roboto,sans-serif;background:var(--bg);color:var(--ink);line-height:1.5}
.top{background:var(--pri);color:#fff;padding:14px 16px;position:sticky;top:0;z-index:5}
.top h1{margin:0;font-size:1.15rem}.top p{margin:2px 0 0;opacity:.85;font-size:.9rem}
.back{color:#fff;font-size:.85rem;text-decoration:none;opacity:.9}
.bar{height:6px;background:#ffffff40;border-radius:3px;margin-top:8px;overflow:hidden}
#progress{height:100%;width:0;background:#fff;transition:width .3s}
.wrap{max-width:760px;margin:0 auto;padding:16px}
.card{background:var(--card);border:1px solid var(--bd);border-radius:14px;padding:16px;margin-bottom:14px;box-shadow:0 1px 3px #0001}
a.unit,.unit{display:flex;gap:14px;align-items:center;text-decoration:none;color:inherit}
a.unit:hover{border-color:var(--pri)}.unit.locked{opacity:.5}
.unit .ic{font-size:2.4rem}.unit h2{margin:0}.unit p{margin:0}.unit small{color:var(--mut)}
h2.part{margin:6px 0 4px}.sub{color:var(--mut);margin:0 0 12px;font-size:.92rem}
.tabs{display:flex;gap:6px;flex-wrap:wrap;margin-bottom:14px}
.tab{border:1px solid var(--bd);background:#fff;border-radius:20px;padding:6px 14px;cursor:pointer;font-size:.9rem}
.tab.on{background:var(--pri);color:#fff;border-color:var(--pri)}
.tab.done::after{content:" ✓"}
button{font:inherit;cursor:pointer}
.btn{background:var(--pri);color:#fff;border:0;border-radius:10px;padding:10px 16px}
.btn.alt{background:#fff;color:var(--pri);border:1px solid var(--pri)}
.btn.sm{padding:6px 10px;font-size:.85rem}
.play{display:inline-flex;gap:6px;align-items:center}
.row{display:flex;gap:8px;flex-wrap:wrap;align-items:center;margin:8px 0}
.opt{display:block;width:100%;text-align:left;background:#fff;border:1px solid var(--bd);border-radius:10px;padding:10px 12px;margin:6px 0}
.opt:hover:not(:disabled){border-color:var(--pri)}
.opt.ok{background:#dcfce7;border-color:var(--ok)}.opt.bad{background:#fee2e2;border-color:var(--bad)}
.q{font-weight:600;margin:10px 0 4px}
.tag{display:inline-block;font-size:.72rem;background:#eef;color:var(--pri);border-radius:8px;padding:1px 8px;margin-right:6px}
input[type=text]{font:inherit;padding:7px 10px;border:1px solid var(--bd);border-radius:8px;width:200px;max-width:100%}
input.ok{border-color:var(--ok);background:#dcfce7}input.bad{border-color:var(--bad);background:#fee2e2}
.fb{font-size:.88rem;margin-top:4px;min-height:1em}.fb.ok{color:var(--ok)}.fb.bad{color:var(--bad)}
.dlg p{margin:8px 0}.dlg b{color:var(--pri)}.dlg input{width:110px;padding:3px 6px}
.vocab{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:8px}
.vocab div{background:#f1f3fb;border-radius:10px;padding:8px;font-size:.9rem}
.vocab span{font-size:1.5rem;display:block}
.vocab.wide{grid-template-columns:1fr}.vocab.wide div{display:flex;gap:10px;align-items:center}.vocab.wide span{display:inline}
.score{font-size:2rem;font-weight:700;text-align:center}
.nav{display:flex;justify-content:space-between;margin:10px 0 30px}
.hint{background:#fff7e0;border-radius:8px;padding:8px 10px;font-size:.85rem;margin-top:8px}
.warn{background:#fee2e2;border-radius:8px;padding:8px 10px;font-size:.85rem}
select{font:inherit;padding:5px;border-radius:8px}