/* ===== Content styles carried over from v1: explanation detail, question images, teaching animations, printable paper ===== */
/* ---------- 詳情解釋（答錯：錯喺邊／正確做法／正確答案） ---------- */
.fb-detail{margin-top:12px;display:flex;flex-direction:column;gap:13px}
.fb-sec p{margin:0;font-size:16px;line-height:1.62}
.fb-sec-h{display:inline-flex;align-items:center;font-size:13px;font-weight:800;letter-spacing:.05em;padding:3px 11px;border-radius:999px;background:var(--surface);border:1px solid var(--line-2);color:var(--ink-2);margin-bottom:6px}
.feedback.no .fb-sec-h{border-color:var(--bad-line);color:var(--bad)}
.fb-steps{margin:0;padding-left:23px;font-size:16px;line-height:1.66;color:var(--ink)}
.fb-steps li{margin:3px 0}
.fb-sec-ans{display:flex;align-items:center;gap:11px;flex-wrap:wrap}
.fb-sec-ans .fb-sec-h{margin-bottom:0}
.fb-answer{font-size:20.5px;font-weight:800}
.fb-userline{font-size:15px;color:var(--ink-2);margin-bottom:2px}
/* ---------- 題目附圖（重繪） ---------- */
.qimg{background:var(--surface);border:1px solid var(--line);border-radius:var(--r-m);padding:18px;margin:16px 0 4px;display:flex;flex-direction:column;align-items:center;gap:10px;box-shadow:var(--sh-1)}
.qimg-emoji{font-size:54px;line-height:1.25;letter-spacing:6px;text-align:center}
.qimg-boxes{display:flex;gap:8px;flex-wrap:wrap;justify-content:center}
.qimg-box{border:2px solid var(--acc);border-radius:10px;padding:8px 11px;font-weight:700;font-size:14.5px;background:var(--acc-soft);color:var(--ink)}
.qimg-dots{display:flex;gap:6px;flex-wrap:wrap;justify-content:center;max-width:430px}
.qimg-solids{display:flex;gap:30px;flex-wrap:wrap;justify-content:center}
.qimg-solid{text-align:center;font-weight:800;font-size:16px}
/* ---------- lesson player & animations ---------- */
.anim{background:var(--surface);border:1px solid var(--line);border-radius:var(--r-l);
  padding:24px;margin:16px 0;min-height:132px;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:14px;overflow:hidden}
.anim .row{display:flex;gap:10px;flex-wrap:wrap;align-items:center;justify-content:center}
.chip2{background:var(--surface);border:1.5px solid var(--line-2);border-radius:var(--r-s);padding:9px 15px;font-size:20px;font-weight:700;animation:pop .4s ease both}
@keyframes pop{from{transform:scale(.85);opacity:0}to{transform:scale(1);opacity:1}}
@keyframes slidein{from{transform:translateX(-24px);opacity:0}to{transform:none;opacity:1}}
.slidein{animation:slidein .45s ease both}
.bubble{align-self:flex-start;background:var(--surface-2);border:1px solid var(--line);border-radius:14px;border-bottom-left-radius:4px;padding:12px 16px;max-width:85%;animation:pop .35s ease both}
.bubble.r{align-self:flex-end;background:var(--acc-soft);border-color:var(--line);border-radius:14px;border-bottom-right-radius:4px;color:var(--ink)}
.nl{position:relative;width:92%;height:54px}
.nl .axis{position:absolute;left:0;right:0;top:26px;height:3px;background:var(--mut);border-radius:2px}
.nl .tick{position:absolute;top:20px;width:2px;height:14px;background:var(--mut)}
.nl .tlab{position:absolute;top:36px;transform:translateX(-50%);font-size:13px;color:var(--mut)}
.nl .dot{position:absolute;top:14px;width:26px;height:26px;border-radius:50%;background:var(--bad);color:#fff;font-weight:800;display:flex;align-items:center;justify-content:center;transform:translateX(-50%);transition:left 1s ease;font-size:13px}
table.vt{border-collapse:collapse;font-size:19px}
table.vt td,table.vt th{border:1px solid var(--line);padding:8px 15px;text-align:center;background:var(--surface)}
table.vert{border-collapse:collapse;font-size:30px;font-weight:800;font-variant-numeric:tabular-nums}
table.vert td{width:48px;height:54px;text-align:center}
table.vert tr.line td{border-bottom:3px solid var(--ink)}
table.vert .carry{font-size:16px;color:var(--bad);height:24px}
table.vert .borrow{font-size:15px;color:var(--bad);text-decoration:line-through}
table.vert td.hl{background:var(--acc-soft);border-radius:8px}
.vin{width:46px;height:50px;font-size:26px;text-align:center;font-weight:800;padding:4px}
.vin.bad{border-color:var(--bad);background:var(--bad-bg)}
.coin{width:58px;height:58px;border-radius:50%;background:#F3DFA0;color:#6B4E00;font-weight:800;display:flex;align-items:center;justify-content:center;font-size:15px;border:2px solid #D9B84A;animation:pop .35s ease both;text-align:center}
.obj{font-size:28px;animation:pop .3s ease both;color:var(--acc)}
.obj-dot{width:26px;height:26px;border-radius:50%;background:var(--acc);display:inline-block}
.pan{width:96px;text-align:center;font-weight:800;font-size:19px}
.scale-ic{color:var(--mut);display:inline-flex}
.scale-ic svg{width:30px;height:30px}
.clock{width:150px;height:150px}
.barwrap{display:flex;align-items:flex-end;gap:14px;height:110px}
.barwrap .bar{width:56px;background:var(--acc);border-radius:8px 8px 0 0;color:#fff;font-weight:800;display:flex;align-items:flex-start;justify-content:center;padding-top:6px;transition:height 1s ease}
.lesson-actions{display:flex;gap:12px;flex-wrap:wrap;margin-top:8px}
.lesson-actions .primary{flex:1;min-width:200px}
/* ---------- v3 teaching animations ---------- */
@keyframes dropin{from{transform:translateY(-26px);opacity:0}to{transform:none;opacity:1}}
@keyframes fillup{from{height:6%}to{height:72%}}
@keyframes growbar{from{transform:scaleY(0)}to{transform:scaleY(1)}}
@keyframes pulse-soft{0%,100%{transform:scale(1)}50%{transform:scale(1.12)}}
@keyframes sweepdot{from{offset-distance:0%}to{offset-distance:100%}}
.mp{display:flex;flex-direction:column;gap:9px;width:min(100%,520px)}
.mp-row{display:flex;align-items:center;gap:12px;animation:slidein .45s ease both}
.mp-l{background:var(--surface);border:1.5px solid var(--acc);color:var(--acc);border-radius:10px;padding:8px 14px;font-weight:800;font-size:18px;min-width:118px;text-align:center}
.mp-arrow{color:var(--mut);font-weight:800}
.mp-r{font-size:17.5px;font-weight:650}
.c2{display:grid;grid-template-columns:1fr 1fr;gap:14px;width:min(100%,560px)}
.c2-panel{border:1.5px solid var(--line-2);border-radius:14px;padding:16px;background:var(--surface);animation:pop .45s ease both}
.c2-panel.good{border-color:var(--ok);background:var(--ok-bg)}
.c2-panel h4{margin:0 0 6px;font-size:18.5px;font-weight:800}
.c2-panel p{margin:0;font-size:15.5px;color:var(--ink-2);line-height:1.55}
@media(max-width:560px){.c2{grid-template-columns:1fr}}
.tl{width:min(100%,600px)}
.tl-track{display:flex;align-items:flex-start;position:relative;margin-top:6px}
.tl-track::before{content:"";position:absolute;left:4%;right:4%;top:11px;height:3px;background:var(--line-2);border-radius:2px}
.tl-ev{flex:1;text-align:center;position:relative;padding:0 4px;animation:pop .45s ease both}
.tl-dot{width:23px;height:23px;border-radius:50%;background:var(--acc);color:#fff;font-size:12px;font-weight:800;display:flex;align-items:center;justify-content:center;margin:0 auto 8px;position:relative;z-index:1;box-shadow:0 0 0 4px var(--surface-2)}
.tl-ev b{display:block;font-size:16.5px;line-height:1.35}
.tl-ev span{font-size:13.5px;color:var(--mut);line-height:1.4;display:block}
.stroke-wrap{text-align:center}
.stroke-chars{display:flex;gap:12px;justify-content:center;flex-wrap:wrap}
.stroke-char{position:relative;width:74px;height:74px;border:1.5px dashed var(--line-2);border-radius:12px;background:var(--surface);
  display:flex;align-items:center;justify-content:center;font-size:42px;font-weight:800;animation:pop .5s ease both}
.stroke-char i{position:absolute;top:-9px;left:-9px;width:22px;height:22px;border-radius:50%;background:var(--acc);color:#fff;font-size:12.5px;font-weight:800;font-style:normal;display:flex;align-items:center;justify-content:center}
.ro{text-align:center;width:min(100%,560px)}
.ro-row{display:flex;gap:9px;justify-content:center;flex-wrap:wrap;margin:8px 0}
.ro-chip{background:var(--surface-2);border:1.5px dashed var(--line-2);border-radius:10px;padding:8px 14px;font-size:19px;font-weight:700;color:var(--mut)}
.ro-chip.final{background:var(--surface);border:1.5px solid var(--acc);color:var(--ink);animation:slidein .5s ease both;box-shadow:var(--sh-1)}
.ro-arrow{color:var(--acc);font-size:20px;font-weight:800}
.punct-line{font-size:24px;font-weight:700;line-height:1.7;text-align:center;max-width:560px}
.punct-mark{display:inline-flex;align-items:center;justify-content:center;min-width:38px;height:38px;padding:0 6px;margin:0 2px;
  border-radius:50%;border:2.5px solid var(--bad);color:var(--bad);font-weight:800;animation:pulse-soft 1.6s ease both;background:var(--bad-bg)}
.punct-note{margin-top:12px}
.pb{display:flex;gap:18px;align-items:flex-end;justify-content:center;flex-wrap:wrap}
.pb-group{text-align:center;animation:pop .5s ease both}
.pb-blocks{display:flex;gap:4px;justify-content:center;align-items:flex-end;min-height:56px}
.pb-h{width:52px;height:52px;border-radius:8px;background:var(--acc);opacity:.9;background-image:linear-gradient(var(--surface) 1px,transparent 1px),linear-gradient(90deg,var(--surface) 1px,transparent 1px);background-size:10px 10px}
.pb-t{width:13px;height:52px;border-radius:4px;background:var(--ok)}
.pb-o{width:15px;height:15px;border-radius:4px;background:var(--bad)}
.pb-lab{margin-top:8px;font-weight:800;font-size:16px}
.hop{display:flex;align-items:center;gap:6px;flex-wrap:wrap;justify-content:center;max-width:640px}
.hop-chip{background:var(--surface);border:2px solid var(--acc);border-radius:12px;padding:9px 15px;font-size:20px;font-weight:800;animation:pop .45s ease both;box-shadow:var(--sh-1)}
.hop-chip.last{background:var(--acc);color:#fff}
.hop-jump{text-align:center;color:var(--acc);font-weight:800;font-size:14.5px;animation:pop .45s ease both}
.hop-jump .arc{display:block;font-size:19px;line-height:1}
.tf-wrap{display:flex;gap:14px;align-items:flex-start;justify-content:center;flex-wrap:wrap}
.tf{border:2px solid var(--line-2);border-radius:10px;padding:5px;display:grid;grid-template-columns:repeat(5,17px);gap:4px;background:var(--surface)}
.tf i{width:17px;height:17px;border-radius:50%;background:var(--surface-3)}
.tf i.on{background:var(--acc);animation:pop .3s ease both}
.tf-one{display:flex;gap:4px;padding-top:5px}
.tf-one i{width:17px;height:17px;border-radius:50%;background:var(--bad);animation:pop .3s ease both}
.cal{width:min(100%,520px)}
.cal-grid{display:flex;flex-wrap:wrap;gap:8px;justify-content:center}
.cal-cell{background:var(--surface);border:1.5px solid var(--line-2);border-radius:10px;padding:9px 13px;font-size:16.5px;font-weight:700;animation:pop .4s ease both}
.cal-cell.hl{background:var(--acc);border-color:var(--acc);color:#fff;box-shadow:0 4px 12px rgba(43,92,230,.3)}
.cal-cap{text-align:center;margin-top:12px}
.ang-wrap{display:flex;gap:20px;justify-content:center;flex-wrap:wrap}
.ang{text-align:center;animation:pop .5s ease both}
.ang b{display:block;font-size:17.5px;margin-top:4px}
.ang span{font-size:13.5px;color:var(--mut)}
.comp-wrap{text-align:center}
.comp-route{display:flex;gap:9px;justify-content:center;flex-wrap:wrap;margin-top:14px}
.grp-wrap{display:flex;gap:12px;justify-content:center;flex-wrap:wrap;max-width:600px}
.grp{border:2px dashed var(--acc);border-radius:16px;padding:11px 13px;display:flex;gap:6px;flex-wrap:wrap;max-width:150px;justify-content:center;animation:pop .45s ease both;background:var(--surface)}
.grp.rem{border-color:var(--bad)}
.grp i{width:19px;height:19px;border-radius:50%;background:var(--acc)}
.grp.rem i{background:var(--bad)}
.wp-wrap{display:flex;gap:13px;justify-content:center;flex-wrap:wrap}
.wp-card{width:118px;background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:14px 10px;text-align:center;box-shadow:var(--sh-1);animation:slidein .5s ease both}
.wp-badge{width:46px;height:46px;border-radius:50%;background:var(--acc-soft);color:var(--acc);font-size:23px;font-weight:800;display:flex;align-items:center;justify-content:center;margin:0 auto 8px}
.wp-card b{display:block;font-size:18.5px}
.wp-card span{font-size:13px;color:var(--mut)}
.pour{display:flex;gap:36px;justify-content:center;flex-wrap:wrap}
.cup{width:104px;text-align:center}
.cup-body{height:104px;border:2.5px solid var(--line-2);border-top:none;border-radius:0 0 16px 16px;position:relative;overflow:hidden;background:var(--surface)}
.cup-fill{position:absolute;left:0;right:0;bottom:0;background:var(--acc);opacity:.55;animation:fillup 1.4s ease both}
.cup-dot{position:absolute;width:19px;height:19px;border-radius:50%;background:var(--bad);animation:dropin .6s ease both}
.cup-lab{margin-top:9px;font-weight:800;font-size:16.5px}
.dist{width:min(100%,580px)}
.dist-track{position:relative;height:104px;border-bottom:3px solid var(--line-2);margin:0 8px}
.dist-person{position:absolute;left:2%;bottom:8px;text-align:center;font-size:13px;font-weight:700;color:var(--mut)}
.dist-person i{display:block;width:26px;height:26px;border-radius:50%;background:var(--ink-2);margin:0 auto 3px}
.dist-obj{position:absolute;bottom:8px;text-align:center;animation:pop .5s ease both}
.dist-obj .box{display:inline-flex;border:2px solid var(--acc);background:var(--surface);border-radius:10px;padding:7px 12px;font-weight:800;font-size:16.5px;box-shadow:var(--sh-1)}
.dist-obj span{display:block;font-size:13px;color:var(--mut);margin-top:4px;font-weight:700}
.chg{display:flex;align-items:center;gap:7px;flex-wrap:wrap;justify-content:center}
.chg-chip{background:var(--surface);border:2px solid var(--line-2);border-radius:12px;padding:9px 14px;font-size:19px;font-weight:800;animation:pop .45s ease both}
.chg-chip.last{border-color:var(--ok);background:var(--ok-bg);color:var(--ok)}
.chg-step{color:var(--ok);font-weight:800;font-size:15px;animation:pop .45s ease both;text-align:center}
.solid-wrap{display:flex;gap:20px;justify-content:center;flex-wrap:wrap}
.solid{text-align:center;animation:pop .55s ease both}
.solid b{display:block;margin-top:7px;font-size:16.5px}
.rad{display:flex;align-items:center;gap:13px;justify-content:center;flex-wrap:wrap}
.rad-part{width:70px;height:70px;border:1.5px solid var(--line-2);border-radius:12px;background:var(--surface);display:flex;align-items:center;justify-content:center;font-size:37px;font-weight:800}
.rad-part.from-l{animation:slidein .6s ease both}
.rad-part.from-r{animation:slidein .6s ease both;animation-name:slidein-r}
@keyframes slidein-r{from{transform:translateX(24px);opacity:0}to{transform:none;opacity:1}}
.rad-op{font-size:24px;font-weight:800;color:var(--mut)}
.rad-res{width:80px;height:80px;border:2.5px solid var(--acc);border-radius:14px;background:var(--acc-soft);color:var(--acc);display:flex;align-items:center;justify-content:center;font-size:45px;font-weight:800;animation:pop .55s ease .45s both}
.sort-wrap{display:flex;align-items:flex-end;gap:20px;height:132px;justify-content:center}
.sort-col{text-align:center}
.sort-bar{margin:0 auto;width:62px;background:var(--grad);border-radius:9px 9px 0 0;transform-origin:bottom;animation:growbar .8s ease both;box-shadow:var(--sh-1)}
.sort-col b{display:block;margin-top:8px;font-size:15px}
.vert-ans{display:inline-block;animation:pop .45s ease both}
.carry-pulse{animation:pulse-soft 1.4s ease both;color:var(--bad);font-weight:800}
/* parity pass: vertical borrow marks + per-column captions, fold, balance motion */
table.vert td.vmark{font-size:15px;color:var(--bad);font-weight:800;height:22px;line-height:1}
table.vert td.struck{text-decoration:line-through;text-decoration-color:var(--bad);text-decoration-thickness:2.5px;color:var(--mut)}
.vcaps{margin:14px auto 0;max-width:540px;text-align:left}
.vcap{font-size:16.5px;line-height:1.55;margin:5px 0;padding:2px 0 2px 14px;border-left:3px solid var(--acc)}
.fold-wrap{text-align:center}
.fold-half{transform-box:view-box;animation:foldflip 2.8s ease .6s both}
@keyframes foldflip{0%{transform:scaleX(1)}50%,100%{transform:scaleX(-1)}}
.pan{animation:pop .45s ease both}
.scale-ic{animation:rock 2.2s ease .35s both;transform-origin:50% 30%}
@keyframes rock{0%{transform:rotate(0)}25%{transform:rotate(5deg)}55%{transform:rotate(-4deg)}80%{transform:rotate(2deg)}100%{transform:rotate(0)}}


/* ---------- printable traditional paper ---------- */
#printRoot{display:none}
body.paper-printing{background:#fff}
body.paper-printing #printRoot{display:block}
.pp-toolbar{position:sticky;top:0;z-index:60;display:flex;gap:12px;align-items:center;flex-wrap:wrap;background:#171B24;color:#EDF1F7;padding:12px 16px;font-size:14.5px}
.pp-toolbar .primary{margin-left:auto}
.pp-doc{font-family:"PingFang HK","PingFang TC","Noto Sans TC","Noto Sans CJK TC","Microsoft JhengHei",sans-serif;color:#000;background:#fff;max-width:800px;margin:0 auto;padding:28px 30px 40px;font-size:12.5pt;line-height:1.65}
.pp-brand{text-align:center;font-size:10.5pt;letter-spacing:.35em;color:#333}
.pp-title{text-align:center;font-size:19pt;font-weight:800;margin:6px 0 14px}
.pp-meta{display:flex;gap:10px;align-items:stretch;margin-bottom:12px}
.pp-fields{flex:1;display:flex;flex-wrap:wrap;gap:8px 26px;align-items:flex-end;font-size:12pt;padding-bottom:4px}
.pp-u{display:inline-block;border-bottom:1.5px solid #000;min-width:110px;padding:0 8px;font-weight:700}
.pp-u.sm{min-width:56px}
.pp-scorebox{border:2px solid #000;min-width:128px;text-align:center}
.pp-scorebox .sb-h{border-bottom:1.5px solid #000;font-size:10.5pt;padding:3px 6px;font-weight:700}
.pp-scorebox .sb-v{font-size:17pt;font-weight:800;padding:5px 6px}
.pp-note{border:1.5px solid #000;padding:9px 13px;font-size:11pt;line-height:1.7;margin-bottom:16px}
.pp-passage{border:1.5px solid #000;padding:12px 15px;white-space:pre-wrap;line-height:1.95;margin:16px 0 6px;font-size:12pt}
.pp-q{margin:15px 0;page-break-inside:avoid}
.pp-qtext{font-weight:700}
.pp-opts{display:flex;flex-wrap:wrap;gap:5px 30px;margin:6px 0 0 24px;font-weight:400}
.pp-opts.grid2{display:grid;grid-template-columns:1fr 1fr;gap:5px 24px}
.pp-opts.vert{display:block}
.pp-opts.vert>div{margin:5px 0}
.pp-bank{border:1.5px dashed #000;padding:8px 13px;margin:8px 0 0 24px;display:inline-block}
.pp-line{border-bottom:1.5px solid #888;height:30px;margin:6px 0 0 24px}
.pp-line.short{width:46%}
.pp-img{margin:8px 0 0 24px}
.pp-end{text-align:center;font-weight:700;margin:26px 0 6px;letter-spacing:.2em}
.pp-key{page-break-before:always}
.pp-key h2{text-align:center;font-size:16pt;margin:4px 0 6px}
.pp-key .pp-keysub{text-align:center;font-size:11pt;margin:0 0 14px}
table.pp-kt{width:100%;border-collapse:collapse;font-size:11.5pt}
table.pp-kt th,table.pp-kt td{border:1.5px solid #000;padding:5px 9px;text-align:left;vertical-align:top}
table.pp-kt th{text-align:center;background:#eee}
table.pp-kt td.c{text-align:center;white-space:nowrap}
.pp-keynote{font-size:11pt;margin-top:14px;line-height:1.75}
/* ---------- 已改卷（紅筆批改版） ---------- */
.pp-doc,.pp-doc *{-webkit-print-color-adjust:exact;print-color-adjust:exact}
.pp-marked-banner{text-align:center;color:#C8102E;font-weight:800;font-size:13pt;letter-spacing:.12em;border:2px solid #C8102E;border-radius:8px;padding:5px 10px;margin:0 auto 12px;max-width:430px;background:#FDF0F2}
.pp-meta{position:relative}
.pp-stamp{position:absolute;right:150px;top:0;transform:rotate(-8deg);color:#C8102E;border:2.5px solid #C8102E;border-radius:8px;padding:3px 12px;font-size:14pt;font-weight:800;letter-spacing:.25em;background:rgba(253,240,242,.85)}
.pp-mark{color:#C8102E;font-weight:900;font-size:14pt;margin-left:8px}
.pp-qscore{float:right;color:#C8102E;font-weight:800;border:1.5px solid #C8102E;border-radius:6px;padding:0 9px;font-size:11.5pt;background:#FDF0F2}
.pp-fillb{color:#1D4ED8;font-weight:800}
.pp-opt-pick{font-weight:700}
.pp-picktag{color:#1D4ED8;font-weight:700;font-size:11pt;white-space:nowrap}
.pp-opt-right{font-weight:700}
.pp-righttag{color:#C8102E;font-weight:800;font-size:11pt;white-space:nowrap}
.pp-line.filled{height:auto;min-height:28px;padding:2px 4px}
.pp-hand{color:#1D4ED8;font-weight:700;font-size:12.5pt}
.pp-correct{margin:8px 0 0 24px;border:1.5px solid #C8102E;background:#FDF0F2;color:#8F0E24;padding:7px 12px;font-size:11.5pt;page-break-inside:avoid}
.pp-correct b{color:#C8102E}
.pp-summary{border:2px solid #000;padding:12px 15px;margin-top:16px;font-size:11.5pt;line-height:1.8}
.pp-summary h3{margin:0 0 6px;font-size:13.5pt}
@media print{
  body>*{display:none!important}
  body>#printRoot{display:block!important}
  .pp-toolbar{display:none!important}
  .pp-doc{max-width:none;padding:0}
}
@page{size:A4;margin:16mm 15mm 17mm}