@keyframes _si{from{opacity:0}to{opacity:1}}

.legacy-content .lesson-header .kicker {color:var(--ds)}.legacy-content .l-callout b {color:var(--ds)}.legacy-content .trie-box {background:var(--card);border:1.5px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-card);overflow:hidden}.legacy-content .trie-head {padding:14px 22px;border-bottom:1px solid var(--border);background:rgba(0,0,0,.015);display:flex;align-items:center;gap:10px;flex-wrap:wrap}.legacy-content .trie-head-label {font-size:12px;font-weight:800;color:var(--sub)}.legacy-content .sent-chip {border:1.5px solid var(--border);background:var(--card);border-radius:999px;padding:6px 16px;font-size:13.5px;font-weight:700;color:var(--text);cursor:pointer;transition:all .15s;font-family:inherit}.legacy-content .sent-chip:hover {border-color:rgba(2,132,199,.4)}.legacy-content .sent-chip.active {background:var(--ds);border-color:var(--ds);color:#fff}.legacy-content .trie-sentence {padding:16px 22px 6px;text-align:center}.legacy-content .trie-sentence .sc {display:inline-block;font-size:22px;font-weight:800;padding:5px 9px;margin:0 2px;border-radius:9px;color:var(--text);transition:background .25s,color .25s,opacity .25s}.legacy-content .trie-sentence .sc.probe {background:var(--ds);color:#fff}.legacy-content .trie-sentence .sc.eaten {background:var(--ds-soft);color:var(--ds-deep);opacity:.65}.legacy-content .trie-stage {padding:4px 12px;display:flex;justify-content:center}.legacy-content .trie-stage svg {width:100%;max-width:640px;height:auto;display:block}.legacy-content .tr-edge {stroke:rgba(0,0,0,.16);stroke-width:1.8;transition:stroke .25s,stroke-width .25s}.legacy-content .tr-edge.path {stroke:var(--ds);stroke-width:3}.legacy-content .tr-node circle.tr-dot {fill:#fff;stroke:rgba(0,0,0,.22);stroke-width:1.6;transition:fill .25s,stroke .25s}.legacy-content .tr-node text.tr-char {fill:var(--text);font-size:15px;font-weight:800;pointer-events:none}.legacy-content .tr-node.cur circle.tr-dot {fill:var(--ds);stroke:var(--ds)}.legacy-content .tr-node.cur text.tr-char {fill:#fff}.legacy-content .tr-node.path circle.tr-dot {fill:var(--ds-soft);stroke:var(--ds)}.legacy-content .tr-node.cut circle.tr-dot {fill:#dcfce7;stroke:var(--success)}.legacy-content .tr-end {fill:#16a34a;font-size:11px;font-weight:900}.legacy-content .tr-root-label {fill:var(--sub);font-size:11px;font-weight:700}.legacy-content .trie-narr {margin:6px 22px;padding:13px 16px;background:var(--ds-soft);border:1.5px dashed var(--ds-line);border-radius:var(--radius-sm);font-size:13px;line-height:1.8;color:var(--sub);min-height:58px}.legacy-content .trie-narr b {color:var(--ds-deep)}.legacy-content .trie-narr .bad {color:var(--danger);font-weight:800}.legacy-content .trie-narr .ok {color:var(--success);font-weight:800}.legacy-content .trie-result {display:flex;align-items:center;gap:8px;flex-wrap:wrap;padding:4px 22px 8px;min-height:44px}.legacy-content .trie-result-label {font-size:12px;font-weight:800;color:var(--sub)}.legacy-content .tok-chip {background:var(--ds);color:#fff;font-size:14px;font-weight:800;padding:5px 14px;border-radius:9px;animation:tokPop .35s ease}@keyframes tokPop{0%{transform:scale(.4);opacity:0}70%{transform:scale(1.12)}100%{transform:scale(1);opacity:1}}.legacy-content .trie-foot {display:flex;align-items:center;gap:12px;flex-wrap:wrap;padding:12px 22px 16px;border-top:1px solid var(--border)}.legacy-content .btn-ds {background:var(--ds);color:#fff;border:none;padding:10px 26px;border-radius:999px;font-size:14px;font-weight:800;cursor:pointer;font-family:inherit;transition:filter .15s,transform .15s}.legacy-content .btn-ds:hover:not(:disabled) {filter:brightness(1.08);transform:translateY(-1px)}.legacy-content .btn-ds:disabled {background:#c4c8cf;cursor:not-allowed}.legacy-content .trie-status {font-size:12.5px;color:var(--sub);font-weight:600}.legacy-content .bpe-card {background:var(--card);border:1.5px solid var(--border);border-radius:var(--radius);padding:20px 24px;box-shadow:var(--shadow-card)}.legacy-content .bpe-card h4 {font-size:15px;font-weight:800;color:var(--text);margin-bottom:10px}.legacy-content .bpe-card p {font-size:13.5px;color:var(--sub);line-height:1.85;margin-bottom:10px}.legacy-content .bpe-card p:last-child {margin-bottom:0}.legacy-content .bpe-card b {color:var(--ds-deep)}.legacy-content .bpe-demo {display:flex;align-items:center;gap:8px;flex-wrap:wrap;background:rgba(0,0,0,.03);border-radius:var(--radius-sm);padding:12px 14px;margin:12px 0;font-size:13px}.legacy-content .bpe-tok {padding:3px 10px;border-radius:7px;font-weight:800}.legacy-content .bpe-tok.big {background:var(--ds-soft);color:var(--ds-deep);border:1.5px solid var(--ds-line)}.legacy-content .bpe-tok.frag {background:rgba(220,38,38,.08);color:var(--danger);border:1.5px dashed rgba(220,38,38,.35)}.legacy-content .bpe-arrow {color:var(--sub);font-weight:800}.legacy-content .takeaway-box {background:linear-gradient(135deg,#f0f9ff,#e0f2fe);border:1.5px solid #bae6fd;border-radius:var(--radius);padding:24px 28px;margin-top:36px}.legacy-content .takeaway-box h3 {font-size:17px;font-weight:800;color:var(--ds-deep);margin-bottom:10px}.legacy-content .takeaway-box ul {list-style:none;padding:0;margin:0}.legacy-content .takeaway-box li {font-size:14.5px;color:#0c4a6e;line-height:1.8;padding:4px 0 4px 22px;position:relative}.legacy-content .takeaway-box li::before {content:'';position:absolute;left:0;top:13px;width:8px;height:8px;border-radius:50%;background:var(--ds)}@media (max-width:768px){.legacy-content .trie-sentence .sc {font-size:18px;padding:4px 6px}.legacy-content .trie-narr {margin-left:14px;margin-right:14px}}

.legacy-content .xa-tldr {margin:18px 0 4px;padding:14px 18px;background:rgba(0,102,255,0.04);border:1px solid rgba(0,102,255,0.16);border-radius:10px}.legacy-content .xa-tldr .xa-tldr-tag {display:block;font-size:11px;font-weight:800;letter-spacing:1px;color:var(--accent,#0066ff);margin-bottom:6px}.legacy-content .xa-tldr p {margin:0;font-size:15px;line-height:1.8;color:var(--text,#1f2937)}