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16px;width:100%}.index-screen{flex:1;padding:0 16px 16px;display:flex;flex-direction:column;gap:8px;overflow-y:auto}.index-screen::-webkit-scrollbar{display:none}.idx-label{font-size:.7rem;font-weight:600;letter-spacing:.1em;text-transform:uppercase;color:var(--sub);padding:16px 4px 8px}.chapter-card{background:var(--surf);border:1px solid var(--brd);border-radius:var(--r);padding:16px;display:flex;align-items:center;gap:14px;cursor:pointer;transition:all .15s}.chapter-card:hover{background:var(--surf2);border-color:var(--surf3)}.chapter-card:active{transform:scale(.99)}.ch-num{width:40px;height:40px;border-radius:12px;flex-shrink:0;background:var(--golddim);display:flex;align-items:center;justify-content:center;font-size:.85rem;font-weight:700;color:var(--gold)}.ch-info{flex:1;min-width:0}.ch-name{font-weight:600;font-size:.95rem;margin-bottom:2px}.ch-meta{font-size:.75rem;color:var(--sub);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.ch-arrow{color:var(--dim);font-size:.9rem;flex-shrink:0}.exercise-screen{flex:1;display:flex;flex-direction:column;overflow:hidden}.ex-topbar{flex-shrink:0;padding:12px 16px 0;display:flex;flex-direction:column;gap:8px;background:var(--bg)}.ex-meta{display:flex;align-items:center;justify-content:space-between}.ex-chapter{font-size:.78rem;font-weight:600;color:var(--sub)}.ex-counter{font-size:.78rem;color:var(--dim);font-weight:500}.pbar{height:3px;background:var(--brd);border-radius:2px;overflow:hidden}.pbar-fill{height:100%;background:var(--gold);border-radius:2px;transition:width .35s ease}.ex-content{flex:1;overflow-y:auto;padding:12px 16px 16px;display:flex;flex-direction:column;gap:12px;-webkit-overflow-scrolling:touch}.ex-content::-webkit-scrollbar{display:none}.ex-quote{background:var(--golddim);border-left:3px solid var(--gold);border-radius:0 10px 10px 0;padding:10px 14px;font-style:italic;font-size:.83rem;color:#e8c76a;line-height:1.6}.ex-qbox{background:var(--surf);border:1px solid var(--brd);border-radius:12px;padding:12px 14px}.ex-qlabel{font-size:.62rem;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:var(--gold);margin-bottom:5px}.ex-qtext{font-size:.86rem;line-height:1.68;color:var(--txt)}.board-wrap{display:flex;justify-content:center}.ex-footer{padding:12px 16px;border-top:1px solid var(--brd);background:var(--surf);display:flex;align-items:center;justify-content:space-between;gap:8px;flex-shrink:0;padding-bottom:calc(12px + env(safe-area-inset-bottom,0px))}.btn-nav{flex:1;background:none;border:1px solid var(--brd);color:var(--sub);padding:10px 16px;border-radius:10px;cursor:pointer;font-size:.83rem;font-family:inherit;font-weight:600;transition:all .15s}.btn-nav:hover:not(:disabled){border-color:var(--gold);color:var(--gold)}.btn-nav:disabled{opacity:.25;cursor:not-allowed}.btn-reset{background:none;border:none;color:var(--dim);font-size:1rem;cursor:pointer;font-family:inherit;padding:10px 12px;transition:color 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20px}.fb-icon{width:48px;height:48px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:1.4rem;margin-bottom:12px}.fb-icon.ok{background:var(--ok-bg);color:var(--ok)}.fb-icon.err{background:var(--err-bg);color:var(--err)}.fb-title{font-size:1.1rem;font-weight:700;margin-bottom:6px}.fb-title.ok{color:var(--ok)}.fb-title.err{color:var(--err)}.fb-text{font-size:.88rem;color:var(--sub);line-height:1.65;margin-bottom:20px}.btn-fb{width:100%;padding:15px;border-radius:14px;border:none;cursor:pointer;font-size:.95rem;font-weight:700;font-family:inherit;transition:all .15s}.btn-fb.ok{background:var(--ok);color:#0f0f12}.btn-fb.ok:hover{background:#00daa6}.btn-fb.err{background:var(--surf2);border:1px solid var(--brd);color:var(--txt)}.btn-fb.err:hover{border-color:var(--sub)}