*{box-sizing:border-box}body{margin:0;font-family:system-ui,-apple-system,sans-serif;background:linear-gradient(160deg,#e8fff4,#eef3ff);color:#1d2433;min-height:100vh}
main{max-width:640px;margin:0 auto;padding:18px 16px 40px}h1{font-size:1.5rem;margin:.4rem 0}.sub,.src{color:#667;font-size:.9rem}.src{text-align:center;margin-top:20px}
.card{background:#fff;border-radius:18px;padding:18px;box-shadow:0 6px 20px #0001;margin-top:12px}
.topic{display:flex;gap:14px;align-items:center;background:#fff;border-radius:16px;padding:16px;margin-top:12px;text-decoration:none;color:inherit;box-shadow:0 6px 20px #0001}
.topic .e{font-size:2rem}.topic small{display:block;color:#667;margin-top:2px}.back{color:#2f7a5b;text-decoration:none;font-weight:600}
button{font:inherit;border:0;border-radius:14px;padding:14px;cursor:pointer;background:#2f9e6f;color:#fff;font-weight:700}
.row{display:flex;gap:10px;flex-wrap:wrap}.row button{flex:1;min-width:120px}
.opt{display:block;width:100%;text-align:left;background:#f3f6fb;color:#1d2433;margin:8px 0;font-weight:600;border:2px solid transparent}
.opt.right{background:#dff7e9;border-color:#2f9e6f}.opt.bad{background:#ffe3e3;border-color:#e05555}.opt:disabled{cursor:default}
h2{font-size:1.2rem;line-height:1.4}.count{color:#667;font-size:.85rem;margin:.6rem 0 0}.exp{background:#fffbe8;border-radius:12px;padding:10px 12px;line-height:1.4}
.next{width:100%;margin-top:6px}.bar{height:8px;background:#eef;border-radius:9px;overflow:hidden}#prog{height:100%;background:#2f9e6f;transition:width .3s}
.rv{border-top:1px solid #eee;padding-top:8px;line-height:1.4}

.opt,#q{unicode-bidi:plaintext}.opt{font-size:1.05rem}