.nt-learn-toolbar{display:grid;grid-template-columns:minmax(0,2fr) minmax(150px,1fr);gap:10px;margin-bottom:18px}.nt-learn-toolbar input,.nt-learn-toolbar select,.nt-answer-input{width:100%;min-height:46px;padding:10px 12px;border:1px solid var(--nt-line);border-radius:10px;background:#fff;color:inherit;font:inherit}.nt-study-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.nt-study-card{position:relative;padding:17px;border:1px solid var(--nt-line);border-radius:14px;background:#fff}.nt-study-card h3{margin:4px 0}.nt-study-card p{margin:7px 0;color:var(--nt-muted);line-height:1.6}.nt-study-meta{display:flex;flex-wrap:wrap;gap:6px}.nt-study-meta span{padding:4px 8px;border-radius:999px;background:var(--nt-soft);font-size:.78rem;color:var(--nt-muted)}.nt-flashcard,.nt-question-card{display:grid;gap:12px;max-width:720px;margin:0 auto 20px;padding:24px;border:1px solid var(--nt-line);border-radius:16px;background:var(--nt-soft);text-align:center}.nt-flashcard strong,.nt-question-card strong{font-size:clamp(1.8rem,5vw,3rem)}.nt-flashcard .nt-pinyin{font-size:1.05rem;color:var(--nt-accent)}.nt-quiz-actions{display:flex;flex-wrap:wrap;justify-content:center;gap:8px}.nt-feedback{min-height:26px;font-weight:800}.nt-scoreboard{display:flex;flex-wrap:wrap;gap:8px;margin:0 0 16px}.nt-scoreboard span{padding:8px 11px;border-radius:9px;background:var(--nt-soft);font-size:.86rem}.nt-source-note{padding:12px;border-left:4px solid var(--nt-accent);background:var(--nt-soft);color:var(--nt-muted);font-size:.9rem;line-height:1.6}.nt-space-stage{position:relative;overflow-x:auto;display:flex;align-items:center;gap:18px;min-height:180px;padding:24px;border-radius:16px;background:linear-gradient(135deg,#081027,#16234a);color:#fff}.nt-sun{flex:0 0 76px;width:76px;height:76px;border-radius:50%;background:#fbbf24;box-shadow:0 0 28px #f59e0b}.nt-planet-button{flex:0 0 auto;display:grid;place-items:center;gap:7px;min-width:66px;border:0;background:transparent;color:#fff;cursor:pointer}.nt-planet-dot{display:block;width:var(--planet-size,28px);height:var(--planet-size,28px);border-radius:50%;background:var(--planet-color,#94a3b8);box-shadow:inset -6px -5px 9px rgba(0,0,0,.25)}.nt-mission-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.nt-mission-card{padding:20px;border:1px solid var(--nt-line);border-radius:15px;background:#fff}.nt-mission-card strong{display:block;font-size:1.45rem;margin:8px 0}.nt-progress-track{height:10px;overflow:hidden;border-radius:999px;background:var(--nt-soft)}.nt-progress-track i{display:block;height:100%;background:var(--nt-accent)}@media(max-width:650px){.nt-learn-toolbar,.nt-study-grid,.nt-mission-grid{grid-template-columns:1fr}.nt-tool-workspace{padding-inline:14px}}