/* Standalone illustrations and interaction for verb reduplication. */
[hidden]{display:none!important}
.en-text{font:400 13px/1.65 Arial,'Noto Sans SC',sans-serif;color:#746c61;margin-top:5px;letter-spacing:0;text-transform:none}
.zh{line-height:1.85}
.header-title .en-text{font-size:16px;color:var(--gold)}
.header-sub .en-text,.level-tag .en-text{font-size:12px}
.ex-pinyin{display:none!important;font:400 12px/1.6 Arial,'Segoe UI',sans-serif!important;text-transform:none;color:#7b7265;margin-top:4px}
body.show-pinyin .ex-pinyin{display:block!important}
.lesson-section{padding:22px 24px;margin-bottom:18px;border:1px solid var(--border);border-radius:6px;background:#fff;line-height:1.9}
.lesson-heading{font:600 18px/1.6 'Noto Serif SC',serif;margin:0 0 18px;color:var(--ink)}
#tab0 .lesson-heading{font:600 14px/1.7 'Noto Sans SC',sans-serif;color:var(--gold)}
.lesson-heading .en-text{font-size:12px;color:var(--gold)}
.lesson-discovery{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:20px}
.lesson-card,.lesson-figure{margin:0;min-width:0}
.lesson-photo{display:block;width:100%;height:auto;aspect-ratio:1;object-fit:cover;border-radius:4px}
.lesson-flip{display:grid;grid-template-areas:'face';width:100%;padding:0;border:1px solid var(--border);border-radius:5px;background:#fcfaf5;color:var(--ink);text-align:left;cursor:pointer;overflow:hidden;perspective:1000px;font:inherit}
.lesson-front,.lesson-back{grid-area:face;width:100%;min-width:0;backface-visibility:hidden;transition:transform .35s ease,opacity .25s ease}
.lesson-front{align-self:center}
.lesson-back{padding:20px;display:flex;flex-direction:column;align-items:flex-start;justify-content:center;gap:12px;opacity:0;transform:rotateY(180deg);pointer-events:none}
.lesson-flip[aria-pressed='true'] .lesson-front{opacity:0;transform:rotateY(-180deg);pointer-events:none}
.lesson-flip[aria-pressed='true'] .lesson-back{opacity:1;transform:rotateY(0);pointer-events:auto}
.ivy-avatar{width:52px;height:52px;object-fit:cover;border-radius:50%;flex:none}
.lesson-answer .zh{font:600 20px/1.75 'Noto Serif SC',serif}
.lesson-answer .en-text{font-size:13px}
.lesson-hint{font-size:11px;text-align:center;color:#847564;margin-top:9px;line-height:1.6}
.lesson-hint .en-text{font-size:10px;line-height:1.5;margin-top:3px}
.lesson-patterns{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}
.lesson-pattern{border-left:3px solid var(--gold);background:#f8f6f0;padding:12px 15px}
.lesson-pattern .zh{font-weight:600;font-size:17px}
.lesson-note{font-size:14px;line-height:1.9;margin-top:18px;color:#625a50}
.lesson-example{margin-top:17px;padding:12px 16px;border-left:3px solid #c9ac7c;background:#faf8f3}
.lesson-example .zh{font-size:19px}
.lesson-tip{background:#f4f7f1}
.lesson-tip-head{display:flex;align-items:center;gap:15px;margin-bottom:18px}
.lesson-tip-head .lesson-heading{margin:0}
.ivy-tip-photo{width:64px;height:64px;object-fit:cover;object-position:50% 35%;border-radius:50%;flex:none}
.lesson-detail.with-photo{display:grid;grid-template-columns:minmax(0,1.5fr) minmax(0,1fr);gap:0 28px}
.lesson-detail.with-photo>.lesson-heading{grid-column:1/-1}
.lesson-detail-copy{min-width:0}
.lesson-detail .lesson-figure{align-self:start}
.lesson-caption{font-size:15px;line-height:1.8;margin-top:12px}
.lesson-caption .en-text{font-size:12px}
.lesson-error-block{border-bottom:1px solid var(--border);padding:2px 0 18px;margin-bottom:20px}
.lesson-correction{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px;margin-top:14px}
.lesson-wrong,.lesson-right{position:relative;padding-left:28px;font-size:17px}
.lesson-wrong>.zh{color:#a64a42}.lesson-right>.zh{color:#347749}
.lesson-result-mark{position:absolute;left:0;top:1px;font-size:20px}
.lesson-wrong>.lesson-result-mark{color:#a64a42}.lesson-right>.lesson-result-mark{color:#347749}
.lesson-score{padding:12px 16px;background:#f7f3e9;border-radius:4px;margin-top:20px;font-weight:600;color:var(--gold)}
.lesson-question{padding:22px 24px;margin-bottom:14px;border:1px solid var(--border);border-radius:6px;background:#fff}
.lesson-question.has-photo{display:grid;grid-template-columns:minmax(0,1fr) minmax(180px,.42fr);column-gap:26px}
.lesson-question.has-photo>.lesson-figure{grid-column:2;grid-row:1/4;align-self:start}
.lesson-question-title,.lesson-question-work,.lesson-feedback{grid-column:1;min-width:0}
.lesson-question-title{font-size:17px;font-weight:500;line-height:1.9;position:relative;padding-left:35px;margin:0 0 17px}
.lesson-question-number{position:absolute;left:0;top:1px;font:600 12px/2 'Noto Sans SC',sans-serif;color:var(--gold)}
.lesson-options,.lesson-tiles,.lesson-sentence,.lesson-actions{display:flex;flex-wrap:wrap;gap:10px}
.lesson-option,.lesson-tile,.lesson-chosen,.lesson-action{border:1px solid var(--border);border-radius:4px;background:#faf9f6;color:var(--ink);cursor:pointer;padding:9px 15px;font:500 16px/1.5 'Noto Sans SC',sans-serif}
.lesson-option:hover,.lesson-tile:hover,.lesson-chosen:hover{background:#f1eadc;border-color:#bea77e}
.lesson-option:disabled,.lesson-chosen:disabled{cursor:default}
.lesson-option.is-wrong{border-color:#bb6f66;background:#fcf0ed}
.lesson-option.is-right{border-color:#75a484;background:#eef7ef}
.lesson-option:disabled:not(.is-right){opacity:.55}
.lesson-tile:disabled{opacity:.35;cursor:default}
.lesson-sentence{min-height:54px;margin-bottom:12px;padding:8px;border:1px dashed #c9bda9;border-radius:4px;background:#fdfbf6}
.lesson-chosen{background:#eee5d1;border-color:#d1bf98}
.lesson-actions{margin-top:14px}
.lesson-action{font-size:13px;background:var(--gold);border-color:var(--gold);color:#fff}
.lesson-action .en-text{font-size:11px;color:inherit}
.lesson-action.secondary{background:#fff;color:var(--gold)}
.lesson-action:disabled{opacity:.6;cursor:default}
.lesson-feedback:not(:empty){margin-top:17px;padding:12px 15px;border-radius:4px;background:#faf3e8}
.lesson-feedback-status{font-weight:600;color:#93622a}
.is-correct .lesson-feedback{background:#eff7ee}.is-correct .lesson-feedback-status{color:#337849}
.lesson-explanation{font-size:14px;margin-top:7px;line-height:1.85}
.lesson-reset{margin:7px 0}
.lesson-flip:focus-visible,.lesson-option:focus-visible,.lesson-tile:focus-visible,.lesson-chosen:focus-visible,.lesson-action:focus-visible{outline:2px solid var(--gold);outline-offset:3px}
@media(max-width:900px){.lesson-discovery{gap:14px}.lesson-back{padding:15px}.lesson-answer .zh{font-size:18px}.lesson-detail.with-photo{gap:0 20px}.lesson-correction{grid-template-columns:1fr;gap:12px}}
@media(max-width:680px){.page{padding:14px 12px 0}.header{padding:18px 0}.header-title{font-size:28px}.content{padding:20px 12px}.lesson-section,.lesson-question{padding:18px 16px}.lesson-discovery{grid-template-columns:1fr;gap:24px;max-width:420px;margin:0 auto}.lesson-back{padding:26px}.lesson-answer .zh{font-size:23px}.lesson-patterns{grid-template-columns:1fr}.lesson-detail.with-photo,.lesson-question.has-photo{display:block}.lesson-detail .lesson-figure{margin:22px auto 0;max-width:360px}.lesson-question.has-photo>.lesson-figure{max-width:280px;margin:20px auto 0}.lesson-question-title{font-size:16px}.lesson-heading{font-size:17px}.lesson-option,.lesson-tile,.lesson-chosen{padding:8px 12px;font-size:15px}.site-footer{padding:20px 24px}}
@media(prefers-reduced-motion:reduce){.lesson-front,.lesson-back{transition:none}}