:root {
  color-scheme: dark;
  --bg: #090d19; --panel: #11182b; --panel-2: #17223a; --line: #2b3a5c;
  --text: #f3f6ff; --muted: #9ba9c7; --accent: #58d6bb; --accent-2: #8c7cff;
  --bad: #ff7f8e; --good: #58d6bb;
}
* { box-sizing: border-box; }
html, body { margin: 0; min-height: 100%; }
body { background: radial-gradient(circle at 50% -20%, #1b2d50, var(--bg) 55%); color: var(--text); font: 16px/1.4 system-ui, -apple-system, sans-serif; }
button, select, input { font: inherit; }
button { cursor: pointer; }
.app { height: 100svh; max-width: 680px; margin: auto; padding: max(18px, env(safe-area-inset-top)) 20px max(14px, env(safe-area-inset-bottom)); display: grid; grid-template-rows: auto 1fr auto; }
.topbar { position: relative; display: flex; justify-content: space-between; align-items: center; }
.brand { display: flex; align-items: baseline; gap: 8px; font-size: 1.45rem; font-weight: 800; letter-spacing: -.04em; }
.brand small { color: var(--muted); font-size: .7rem; font-weight: 500; letter-spacing: 0; }
.logo { display: grid; place-items: center; width: 28px; height: 28px; border-radius: 9px; background: var(--accent); color: var(--bg); }
.icon-button { border: 0; background: transparent; color: var(--muted); font-size: 1.5rem; padding: 8px; }
.icon-button:hover, .icon-button:focus-visible { color: var(--text); }
.popover { position: absolute; z-index: 2; right: 0; top: 48px; width: min(290px, calc(100vw - 40px)); padding: 16px; background: var(--panel); border: 1px solid var(--line); border-radius: 16px; box-shadow: 0 15px 45px #0008; }
.popover-title { font-weight: 700; margin-bottom: 12px; }
.popover label { display: grid; gap: 5px; color: var(--muted); font-size: .8rem; margin: 12px 0; }
select, input[type=range] { width: 100%; accent-color: var(--accent); }
select { color: var(--text); background: var(--panel-2); border: 1px solid var(--line); border-radius: 8px; padding: 8px; }
.text-button { color: var(--bad); border: 0; background: none; padding: 5px 0; }
.lesson { display: flex; flex-direction: column; justify-content: center; min-height: 0; }
.progress-row, footer { display: flex; justify-content: space-between; color: var(--muted); font-size: .8rem; }
.progress-track { height: 6px; background: var(--panel-2); border-radius: 5px; margin: 10px 0 20px; overflow: hidden; }
.progress-track span { display: block; height: 100%; width: 0; background: linear-gradient(90deg, var(--accent), var(--accent-2)); transition: width .3s; }
.card { background: #101a30dd; border: 1px solid var(--line); border-radius: 24px; padding: clamp(22px, 6vw, 42px); box-shadow: 0 20px 60px #0003; }
.category { color: var(--accent); font-size: .72rem; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }
.prompt { font-size: clamp(1.6rem, 7vw, 2.7rem); font-weight: 750; letter-spacing: -.04em; margin: 18px 0 13px; }
.listen, .answer-button, .submit { border: 1px solid var(--line); border-radius: 12px; background: var(--panel-2); color: var(--text); padding: 12px 16px; }
.listen { color: var(--accent); }
.listen:hover, .answer-button:hover, .answer-button:focus-visible, .submit:hover { border-color: var(--accent); }
.post-answer { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin-top: 16px; }
.post-answer .listen { margin: 0; }
.post-answer #nextArea:empty { display: none; }
.answers { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 22px; }
.answer-button { min-height: 60px; }
.answer-button.correct { border-color: var(--good); color: var(--good); }
.answer-button.wrong { border-color: var(--bad); color: var(--bad); }
.answer-form { display: flex; gap: 8px; margin-top: 22px; }
.answer-input { min-width: 0; flex: 1; border: 1px solid var(--line); border-radius: 12px; background: var(--panel-2); color: var(--text); padding: 12px 14px; }
.submit { background: var(--accent); border-color: var(--accent); color: var(--bg); font-weight: 700; }
.feedback { min-height: 26px; margin-top: 16px; color: var(--muted); }
.feedback.good { color: var(--good); }.feedback.bad { color: var(--bad); }
.tip { color: var(--muted); font-size: .78rem; text-align: center; margin: 14px 0 0; }
footer { border-top: 1px solid #1d2941; padding-top: 13px; margin-top: 16px; }
@media (max-height: 650px) { .card { padding: 18px 22px; } .prompt { margin: 10px 0; font-size: 1.6rem; } .progress-track { margin-bottom: 10px; } }