/* reading-structure.css — "วิเคราะห์โครงสร้างประโยค" student pages (App/reading/structure/)
   and the shared mark-editor chrome (tool rail, canvas, mark menu, inspector) that Sentence Lab
   reuses. Mark colours themselves come from reading-class-marks.css. */

/* ---------- shared editor chrome (marks-core.js) ---------- */
.mk-rail{display:flex;flex-direction:column;gap:6px;padding:12px 8px;border-right:1px solid var(--color-border);background:#fffef5}
.tool{border:1.5px solid var(--color-border);border-radius:12px;background:var(--color-bg);cursor:pointer;padding:8px 4px 6px;text-align:center;font-family:var(--font-heading-th);color:var(--color-ink);transition:all .12s;position:relative}
.tool:hover{border-color:var(--color-accent);transform:translateY(-1px)}
.tool.active{border-color:var(--color-accent);box-shadow:0 0 0 2px rgba(0,109,64,.18);background:#fff}
.tool__sym{display:block;font-family:var(--font-body-jp);font-size:15px;line-height:1.5;margin:0 auto 3px;min-height:22px}
.tool__sym.sym-s{background:var(--pink);border-radius:4px;padding:1px 6px;display:inline-block}
.tool__sym.sym-p{background:var(--sky);border-radius:4px;padding:1px 6px;display:inline-block}
.tool__sym.sym-sm{color:var(--pink-line);font-weight:700}
.tool__sym.sym-pm{color:var(--sky-line);font-weight:700}
.tool__sym.sym-u{border-bottom:1.5px solid #3a3a3a;display:inline-block;padding:0 4px}
.tool__sym.sym-c{color:var(--red);font-weight:700}
.tool__sym.sym-f{border:1.5px solid var(--red);border-radius:999px;padding:0 8px;display:inline-block}
.tool__sym.sym-m{border:1.5px dotted #3a3a3a;border-radius:6px;padding:0 6px;display:inline-block}
.tool__sym.sym-h{color:#8a8f86;font-style:italic;font-size:12px;border:1px dashed #b5b9b3;border-radius:999px;padding:0 6px;display:inline-block}
.tool__sym.sym-ar{color:var(--ref,#1E8E5A);font-weight:700}
.tool__t{display:block;font-size:11px;font-weight:600;line-height:1.25}
.tool__k{position:absolute;top:4px;right:6px;font-family:var(--font-heading-en);font-size:9.5px;color:var(--color-mute)}
.rail-sep{height:1px;background:var(--color-border);margin:4px 2px}
.mk-rail.readonly .tool{opacity:.35;pointer-events:none}

.mk-canvas{position:relative;background:#fff;border:1px solid var(--color-border);border-radius:16px;padding:22px 26px;font-family:var(--font-body-jp);font-size:17px;color:var(--color-ink);box-shadow:0 2px 10px rgba(0,0,0,.04);user-select:text;-webkit-user-select:text}
.mk-canvas .arrows{position:absolute;left:0;top:0;pointer-events:none;overflow:visible;z-index:5}
.mk-canvas .para{line-height:3;margin:0 0 6px;position:relative}
.mk-canvas .para-label{font-family:var(--font-heading-th);font-size:11.5px;color:var(--color-mute);margin:14px 0 2px;display:flex;gap:10px}
.mk-canvas .para-label b{color:var(--color-accent)}
.mk-canvas .para__th{display:none;font-family:var(--font-body-th);font-size:13px;color:var(--color-ink-soft);line-height:1.85;background:var(--color-bg-alt);border-left:3px solid var(--color-gold);border-radius:0 8px 8px 0;padding:8px 14px;margin:2px 0 14px}
.mk-canvas.show-th .para__th{display:block}
.mk-canvas .s{border-radius:6px;padding:2px 3px;transition:background .12s;cursor:text}
.mk-canvas .s.sel{background:rgba(0,109,64,.06);box-shadow:0 0 0 1.5px rgba(0,109,64,.35)}
.mk-canvas .s-id{font-family:var(--font-heading-th);font-size:9px;color:var(--color-mute);vertical-align:super;margin-right:2px;letter-spacing:.5px;opacity:.75;user-select:none;-webkit-user-select:none}
.mk-canvas .lab-mark{cursor:pointer}
.mk-canvas .lab-mark.focus{outline:2px solid var(--color-accent);outline-offset:2px;border-radius:4px}
.mk-canvas .lab-mark.ar-pick{outline:2px dashed var(--ref,#1E8E5A);outline-offset:2px;border-radius:4px}
.mk-canvas .g-h{user-select:none;-webkit-user-select:none}
.mk-canvas.tool-armed,.mk-canvas.tool-armed .s{cursor:crosshair}
.mk-canvas.readonly .s{cursor:default}
.mk-canvas.readonly .lab-mark{cursor:default}
.mk-canvas .s::selection,.mk-canvas .s *::selection{background:rgba(0,109,64,.28)}
/* ruby-fit.js ข้าม .mk-canvas (ช่วงข้อความ/ไฮไลต์ของเครื่องมือมาร์ก) — ถ้า app.css ตั้ง ruby-overhang:none ทั้งเว็บ
   ให้ canvas นี้กลับไปใช้ overhang ของเบราว์เซอร์ จะได้ไม่กว้างกว่าเดิม */
.mk-canvas ruby{ruby-overhang:auto}
.mk-canvas ruby rt{font-size:.5em;color:var(--color-mute);opacity:0;transition:opacity .15s}
body.furi-on .mk-canvas ruby rt{opacity:1}
.mk-canvas.teacher{background:#FFFDF3;border-color:var(--color-gold)}
.mk-teacherbadge{display:none;position:absolute;top:10px;right:14px;font-family:var(--font-heading-th);font-size:11.5px;font-weight:700;color:#8B6A00;background:var(--color-gold-soft);border:1px solid var(--color-gold);border-radius:999px;padding:3px 10px;z-index:6}
.mk-canvas.teacher .mk-teacherbadge{display:inline-block}

.markmenu{position:absolute;z-index:60;display:none;gap:4px;align-items:center;background:#1f2a24;color:#fff;border-radius:10px;padding:6px 8px;box-shadow:0 8px 24px rgba(0,0,0,.25);font-family:var(--font-heading-th);font-size:12px;flex-wrap:wrap;max-width:520px}
.markmenu.show{display:flex}
.markmenu b{margin-right:4px;color:#cfe7d8}
.markmenu button{border:0;background:rgba(255,255,255,.12);color:#fff;border-radius:7px;padding:4px 8px;cursor:pointer;font-family:inherit;font-size:12px}
.markmenu button:hover{background:rgba(255,255,255,.26)}
.markmenu button.del{background:rgba(217,70,62,.55)}
.markmenu button.del:hover{background:rgba(217,70,62,.9)}

.ins-box{background:var(--color-bg-alt);border:1px solid var(--color-border);border-radius:12px;padding:10px 12px;margin-bottom:12px;font-family:var(--font-heading-th)}
.ins-box .kv{display:grid;grid-template-columns:76px 1fr;gap:4px 8px;font-size:12.5px;line-height:1.7}
.ins-box .kv .k{color:var(--color-mute)}
.ins-box .kv .val{font-family:var(--font-body-jp);color:var(--color-ink)}
.ins-th{font-size:12.5px;color:var(--color-ink-soft);line-height:1.6;margin-top:6px}
.ins-raw{width:100%;box-sizing:border-box;font-family:ui-monospace,Consolas,monospace;font-size:11.5px;line-height:1.6;border:1px solid var(--color-border);border-radius:8px;padding:8px;background:#fff;color:var(--color-ink-soft);min-height:90px;resize:vertical;margin-top:8px}
.ins-actions{display:flex;gap:6px;flex-wrap:wrap;margin-top:8px}
.ins-actions .btn{padding:5px 10px;font-size:12px}
.slist{display:flex;flex-direction:column;gap:4px;font-family:var(--font-heading-th)}
.srow{display:flex;align-items:center;gap:8px;padding:6px 8px;border-radius:9px;border:1px solid transparent;cursor:pointer;font-size:12.5px}
.srow:hover{background:var(--color-bg-alt)}
.srow.sel{border-color:var(--color-accent);background:#fff}
.srow .id{font-family:var(--font-heading-en);font-size:11px;color:var(--color-mute);width:48px;flex:none}
.srow .txt{flex:1;min-width:0;white-space:nowrap;overflow:hidden;text-overflow:ellipsis;font-family:var(--font-body-jp)}
.srow .st{font-size:10.5px;font-weight:700;border-radius:999px;padding:2px 7px;flex:none}
.srow .st.ok{background:var(--color-soft-bg);color:var(--color-accent)}
.srow .st.part{background:var(--color-gold-soft);color:#8B6A00}
.srow .st.none{background:#f1f0e4;color:var(--color-mute)}
.srow .st.db{background:#E2EDF4;color:#1A5276}
.rs-mute{font-size:12.5px;color:var(--color-mute)}

.toast{position:fixed;left:50%;bottom:28px;transform:translateX(-50%) translateY(20px);background:#1f2a24;color:#fff;padding:10px 16px;border-radius:12px;font-size:13px;opacity:0;pointer-events:none;transition:all .18s;z-index:100;max-width:90vw;font-family:var(--font-heading-th)}
.toast.show{opacity:1;transform:translateX(-50%) translateY(0)}
.toast.err{background:#8A2A2A}

/* ---------- student page layout ---------- */
.rs{max-width:1480px;margin:0 auto;padding:0 0 60px}
.rs-top{position:sticky;top:0;z-index:40;display:flex;align-items:center;gap:10px;padding:10px 18px;background:rgba(255,254,239,.94);backdrop-filter:blur(10px);border-bottom:1px solid var(--color-border);flex-wrap:wrap;font-family:var(--font-heading-th)}
.rs-top__t{display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.rs-top__t b{font-size:15px}
.rs-sub{font-size:12.5px;color:var(--color-mute)}
.rs-pill{font-family:var(--font-heading-en);font-size:11px;font-weight:800;border-radius:999px;padding:3px 9px;background:var(--color-accent);color:#fff}
.rs-pill--y{background:var(--color-soft-bg);color:var(--color-accent)}
.rs-top .sp{flex:1}
.rs-status{font-size:12px;color:var(--color-mute)}
.rs-status.ok{color:var(--color-accent)}.rs-status.err{color:var(--color-wrong)}.rs-status.busy{color:var(--color-gold)}
.rs-chk{display:flex;align-items:center;gap:6px;font-size:12.5px;cursor:pointer;user-select:none}
.rs-chk input{margin:0}
.rs-chk.off{opacity:.45;cursor:not-allowed}
.rs-top .btn{padding:7px 12px;font-size:12.5px}
.rs-body{display:grid;grid-template-columns:96px 1fr 340px;min-height:calc(100vh - 120px)}
.rs-rail{position:sticky;top:57px;align-self:start;max-height:calc(100vh - 57px);overflow-y:auto}
.rs-main{padding:16px 24px 40px;min-width:0}
.rs-hint{font-size:12.5px;color:var(--color-mute);margin:0 0 10px;font-family:var(--font-heading-th)}
.rs-hint b{color:var(--color-ink)}
.rs-nav{display:flex;gap:10px;flex-wrap:wrap;margin-top:18px;font-family:var(--font-heading-th)}
.rs-side{border-left:1px solid var(--color-border);background:#fffef5;position:sticky;top:57px;align-self:start;max-height:calc(100vh - 57px);overflow-y:auto;padding:14px 14px 40px}
.rs-side h3{font-family:var(--font-heading-th);font-size:13px;margin:0 0 8px;color:var(--color-accent)}
.rs-loading{color:var(--color-mute);font-family:var(--font-heading-th);font-size:14px}
@media (max-width:1100px){.rs-body{grid-template-columns:96px 1fr}.rs-side{display:none}}
@media (max-width:640px){.rs-body{grid-template-columns:1fr}.rs-rail{position:static;flex-direction:row;flex-wrap:wrap;max-height:none;border-right:0;border-bottom:1px solid var(--color-border)}.mk-rail .tool{width:88px}.rail-sep{display:none}.rs-main{padding:12px 14px 40px}.mk-canvas{padding:16px 14px}}

/* ---------- level index (all passages) ---------- */
.rs-year{margin:26px 0 8px}
.rs-year__h{font-family:var(--font-heading-th);font-weight:700;font-size:16px;color:var(--color-ink);margin:0 0 10px;display:flex;align-items:baseline;gap:10px}
.rs-year__h small{font-weight:400;font-size:12.5px;color:var(--color-mute)}
.rs-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(250px,1fr));gap:12px}
.rs-card{display:block;position:relative;text-decoration:none;color:var(--color-ink);background:var(--color-bg);border:1.5px solid var(--color-border);border-radius:14px;padding:12px 14px 14px;transition:all .15s}
.rs-card:hover{border-color:var(--color-accent);transform:translateY(-2px);box-shadow:var(--shadow-float)}
.rs-card__m{font-family:var(--font-heading-th);font-size:11.5px;color:var(--color-mute)}
.rs-card__t{font-size:14px;line-height:1.6;margin:4px 0 6px;color:var(--color-ink)}
.rs-card__q{font-family:var(--font-heading-th);font-size:11.5px;color:var(--color-accent);font-weight:600}
.rs-card__done,.rs-card__key{display:none;position:absolute;top:10px;font-family:var(--font-heading-th);font-size:10.5px;font-weight:700;border-radius:999px;padding:2px 8px}
.rs-card__done{right:10px;background:var(--color-soft-bg);color:var(--color-accent)}
.rs-card__key{right:10px;background:var(--color-gold-soft);color:#8B6A00}
.rs-card.is-done .rs-card__done{display:inline-block}
.rs-card.has-key .rs-card__key{display:inline-block}
.rs-card.is-done.has-key .rs-card__key{right:88px}

/* the exam-page button (.btn-structure) lives in app.css — exam pages don't load this file */
.tool__sym.sym-t{background:var(--topic);border-radius:4px;padding:1px 6px;display:inline-block}

/* ---------- ✂ teacher sentence segmentation (Sentence Lab only) ---------- */
.tool__sym.sym-x{font-size:17px;color:var(--color-wrong,#C0392B)}
.mk-canvas .seg-cut,.mk-canvas .seg-reset{display:none}
.mk-canvas .seg-custom{font-size:10.5px;font-weight:700;color:#8B6A00;background:var(--color-gold-soft);border-radius:999px;padding:1px 8px}
.mk-canvas.seg-mode .s{outline:1.5px dashed rgba(0,109,64,.5);outline-offset:1px;background:rgba(0,109,64,.035);cursor:text}
.mk-canvas.seg-mode .s.sel{box-shadow:none}
.mk-canvas.seg-mode .lab-mark{cursor:text}
.mk-canvas.seg-mode .seg-cut{display:inline-flex;align-items:center;justify-content:center;width:22px;height:22px;margin:0 3px;border-radius:999px;
  background:#C0392B;color:#fff;font-size:12px;line-height:1;cursor:pointer;vertical-align:middle;user-select:none;-webkit-user-select:none;font-family:var(--font-heading-en);transition:transform .12s}
.mk-canvas.seg-mode .seg-cut:hover{transform:scale(1.2);background:#8A2A2A}
.mk-canvas.seg-mode .seg-cut:hover::after{content:" ลบ";font-size:0}
.mk-canvas.seg-mode .seg-reset{display:inline-block;border:1px solid var(--color-border);background:#fff;border-radius:999px;padding:1px 10px;font-family:inherit;font-size:11px;cursor:pointer;color:var(--color-ink)}
.mk-canvas.seg-mode .seg-reset:hover{border-color:var(--color-accent);color:var(--color-accent)}
.seg-help{display:none;margin:0 0 10px;padding:10px 14px;border-radius:12px;background:#FDF3F2;border:1px solid #E8B9B4;color:#6B2A24;font-family:var(--font-heading-th);font-size:12.5px;line-height:1.7}
.seg-help b{color:#8A2A2A}
.mk-canvas.seg-mode .seg-help{display:block}

/* ---------- こそあ / 前者・後者 pointer words ([R:]) — ported from the class-article page so the Lab and
   the exam structure pages show the same thing: green dotted word, black oval on the phrase it means,
   red dashed arrow to it, Thai summary box (added 2026-09-18) ---------- */
.tool__sym.sym-r{border-bottom:2px dotted var(--ref,#1E8E5A);display:inline-block;padding:0 4px;font-size:13px}
.mk-canvas .g-r{border-bottom:2px dotted var(--ref,#1E8E5A);cursor:pointer;padding-bottom:1px}
.mk-canvas .g-r:hover,.mk-canvas .g-r.on{background:rgba(30,142,90,.14);border-radius:3px}
.mk-canvas .ref-scope{border:1.7px solid #1f1f1f;border-radius:999px;padding:1px 4px;box-decoration-break:clone;-webkit-box-decoration-break:clone;background:rgba(30,142,90,.08)}
.mk-canvas .ref-scope:not(.rs-first){border-left:0;border-top-left-radius:0;border-bottom-left-radius:0;padding-left:0}
.mk-canvas .ref-scope:not(.rs-last){border-right:0;border-top-right-radius:0;border-bottom-right-radius:0;padding-right:0}
.mk-canvas .s.ref-scope-all{outline:1.7px solid #1f1f1f;outline-offset:2px;border-radius:10px;background:rgba(30,142,90,.08)}
.mk-refbox{position:fixed;bottom:14px;left:50%;transform:translateX(-50%);z-index:70;background:#fffef5;border:1.7px solid #1f1f1f;border-radius:14px;padding:10px 14px 12px;box-shadow:0 12px 30px rgba(0,0,0,.18);font-family:var(--font-body-th);font-size:13px;line-height:1.75;color:var(--color-ink);width:min(760px,calc(100vw - 32px))}
.mk-refbox[hidden]{display:none}
.mk-refbox__h{display:flex;align-items:center;gap:10px;margin-bottom:4px}
.mk-refbox__l{font-size:10px;letter-spacing:1.5px;color:var(--ref,#1E8E5A);font-weight:700;text-transform:uppercase}
.mk-refbox__w{font-weight:700;font-size:15px;border-bottom:2px dotted var(--ref,#1E8E5A);font-family:var(--font-body-jp)}
.mk-refbox .x{margin-left:auto;cursor:pointer;color:var(--color-mute);border:1px solid var(--color-border);border-radius:999px;padding:0 8px;background:#fff}
.mk-refbox__row{display:grid;grid-template-columns:58px 1fr;gap:8px;padding:3px 0;border-top:1px dashed rgba(205,217,209,.7)}
.mk-refbox__k{font-size:10.5px;font-weight:700;color:var(--ref,#1E8E5A);letter-spacing:.5px;padding-top:3px}
.mk-refbox__q{font-size:14px;line-height:1.8;overflow-wrap:anywhere;font-family:var(--font-body-jp)}
.mk-refbox__t{color:var(--color-ink-soft)}
.mk-refbox__src{margin-top:6px;display:flex;flex-wrap:wrap;gap:6px;align-items:center;font-size:11.5px;color:var(--color-mute)}
.mk-refbox__src .chip{font-size:10px;font-weight:700;padding:1px 7px;border-radius:999px;background:var(--color-gold,#B89C4A);color:#fff}

/* ---------------- .hw-drill: restricted-tool homework pages (structure-drill/) ---------------- */
.hw-drill .mk-canvas .para-label{display:none}
.hw-drill .mk-canvas{counter-reset:hwitem}
.hw-drill .mk-canvas .para{counter-increment:hwitem;position:relative;padding-left:34px;margin:16px 0}
.hw-drill .mk-canvas .para::before{content:counter(hwitem) ".";position:absolute;left:0;top:1px;font-family:var(--font-heading-en);font-weight:700;color:var(--color-accent);font-size:14px}
.hw-instr{margin:0 18px 6px;padding:12px 16px;border:1.5px dashed var(--color-border);border-radius:14px;background:var(--color-soft-bg);font-family:var(--font-heading-th);font-size:13px;line-height:1.7;color:var(--color-ink-soft)}
.hw-actions{display:flex;gap:10px;flex-wrap:wrap;margin:0 18px 14px}
.hw-actions .btn[disabled]{opacity:.45;cursor:not-allowed}

/* ---------------- modifier-layers drill (opts.headPick, 第3.4課) ---------------- */
.tool__sym.sym-k{background:rgba(255,213,79,.45);border-radius:4px;padding:0 5px;font-weight:700}
.mk-canvas .g-k{background:rgba(255,213,79,.42);border-radius:4px;padding:0 2px;font-weight:700;box-decoration-break:clone;-webkit-box-decoration-break:clone}
.mk-canvas .g-k .g-k{background:rgba(255,170,0,.45)}
/* nested ส่วนขยายซ้อน: each deeper layer's underline sits a step higher and changes colour, so a
   3-deep chain reads as three stacked lines instead of one blurred rule */
.hw-drill .mk-canvas .g-u,.mk-canvas.hw-drill .g-u{border-bottom:2px solid #3a3a3a;padding-bottom:7px}
.hw-drill .mk-canvas .g-u .g-u,.mk-canvas.hw-drill .g-u .g-u{border-bottom:2px solid #B8860B;padding-bottom:4px}
.hw-drill .mk-canvas .g-u .g-u .g-u,.mk-canvas.hw-drill .g-u .g-u .g-u{border-bottom:2px dotted #7c4dff;padding-bottom:1px}
.hw-drill .mk-canvas .para,.mk-canvas.hw-drill .para{line-height:2.6}
.mk-canvas .lab-mark.ar-head{outline:2px solid #1E8E5A;outline-offset:1px;border-radius:4px;background:rgba(30,142,90,.14)}
.mk-canvas.head-pick{outline:2px dashed #E8A317;outline-offset:-2px;cursor:crosshair}
.mk-headpick{position:absolute;top:10px;right:14px;z-index:7;pointer-events:none;font-family:var(--font-heading-th);font-size:12.5px;font-weight:600;color:#7a4b00;background:#FFF3C4;border:1px solid #E8A317;border-radius:999px;padding:4px 12px;box-shadow:0 4px 14px rgba(0,0,0,.12)}
.mk-headpick b{font-weight:800}

/* ---------------- touch marking (iPad / phone) ---------------- */
@media (pointer: coarse) {
  /* while a tool is armed the finger owns the text: no native selection, no copy callout */
  .mk-canvas.tool-armed, .mk-canvas.head-pick { -webkit-user-select: none; user-select: none; -webkit-touch-callout: none; }
  .rs-hint::before { content: "📱 บนไอแพด/มือถือ: กดค้างที่ตัวอักษร ~0.3 วินาที (กรอบขึ้นสีฟ้า) แล้วลาก · "; font-weight: 700; color: var(--color-accent); }
  .rs-rail .tool { min-height: 44px; }
}
.mk-canvas.touch-marking { -webkit-user-select: none; user-select: none; box-shadow: inset 0 0 0 3px rgba(47,127,209,.45); }
.mk-touchsel { position: absolute; inset: 0; pointer-events: none; z-index: 5; }
.mk-touchsel i { position: absolute; background: rgba(47,127,209,.26); outline: 1.5px solid rgba(47,127,209,.65); border-radius: 3px; }
@media (pointer: coarse) {
  /* the head-pick hint must never sit on top of the text the finger is about to select */
  .mk-headpick { position: fixed; top: auto; right: auto; bottom: 14px; left: 50%; transform: translateX(-50%); z-index: 80; white-space: nowrap; max-width: calc(100vw - 24px); overflow: hidden; text-overflow: ellipsis; }
}

/* touch-marking loupe (iOS-style magnifier above the finger) */
.mk-loupe{position:fixed;width:250px;height:74px;border-radius:16px;overflow:hidden;background:#fff;border:2px solid #2F7FD1;box-shadow:0 10px 28px rgba(0,0,0,.28);z-index:90;pointer-events:none}
.mk-loupe__w{position:absolute;left:0;top:0;transform-origin:0 0;will-change:transform;white-space:nowrap;line-height:2.2}
.mk-loupe .para{margin:0}
.mk-loupe .para::before{display:none}
.mk-loupe i.h{position:absolute;background:rgba(47,127,209,.28);outline:1.5px solid rgba(47,127,209,.7);border-radius:3px}

/* per-sentence undo chip — only while a tool is armed (or a head pick is pending) */
.mk-canvas .s{position:relative}
.mk-canvas .s-undo{display:none;position:absolute;left:0;top:-1.05em;font:700 10.5px/1 var(--font-heading-th);padding:3px 8px;border-radius:999px;border:1px solid var(--color-border);background:#fff;color:var(--color-accent);cursor:pointer;z-index:6;white-space:nowrap;box-shadow:0 1px 3px rgba(0,0,0,.08);user-select:none;-webkit-user-select:none}
.mk-canvas.tool-armed .s-undo,.mk-canvas.head-pick .s-undo{display:inline-block}
.mk-canvas .s-undo.off{opacity:.3;pointer-events:none}
.mk-canvas.readonly .s-undo,.mk-canvas.teacher .s-undo{display:none}
.mk-canvas .s-undo:hover{background:var(--color-soft-bg)}
.hw-drill .mk-canvas .s-undo{top:-1.45em}
@media (pointer: coarse){.mk-canvas .s-undo{font-size:12.5px;padding:6px 11px;top:-1.7em}}

/* ---------------- .hw-quiz: "ข้อมูลนี้ของใคร?" part 2 of 第3.6課 (structure-drill) ---------------- */
.hw-quiz{margin:6px 18px 16px;padding:14px 16px 6px;border:1.5px solid var(--color-border);border-radius:16px;background:#fff}
.hw-quiz__h{margin:0 0 10px;font-family:var(--font-heading-th);font-size:16px;color:var(--color-accent)}
.hw-quiz__sub{display:block;font-size:12px;font-weight:500;color:var(--color-ink-soft);margin-top:2px}
.hwq{display:flex;gap:10px;padding:12px 0;border-top:1px dashed var(--color-border)}
.hwq__n{flex:0 0 26px;font-family:var(--font-heading-en);font-weight:700;color:var(--color-accent);font-size:14px;padding-top:2px}
.hwq__body{flex:1;min-width:0}
.hwq__s{font-family:"Zen Maru Gothic",var(--font-jp,sans-serif);font-size:15px;line-height:1.9;color:var(--color-ink);margin-bottom:8px;padding:6px 10px;background:var(--color-soft-bg);border-radius:10px}
.hwq__row{display:flex;flex-wrap:wrap;align-items:center;gap:6px 10px;padding:5px 8px;border-radius:10px;margin:2px 0}
.hwq__lbl{font-family:var(--font-heading-th);font-size:13px;font-weight:600;color:var(--color-ink-soft);min-width:64px}
.hwq__info{font-family:"Zen Maru Gothic",var(--font-jp,sans-serif);font-size:14px;color:var(--color-ink);font-weight:500}
.hwq__opts{display:flex;flex-wrap:wrap;align-items:center;gap:6px 12px}
.hwq__opt{font-family:var(--font-heading-th);font-size:13px;padding:4px 10px;border:1.5px solid var(--color-border);border-radius:999px;cursor:pointer;background:#fff;user-select:none}
.hwq__opt:has(input:checked){border-color:var(--color-accent);background:rgba(30,142,90,.08);font-weight:600}
.hwq__opt input{accent-color:var(--color-accent);margin:0 2px 0 0;vertical-align:-1px}
.hwq__sel{font-family:"Zen Maru Gothic",var(--font-jp,sans-serif);font-size:14px;padding:6px 10px;border:1.5px solid var(--color-border);border-radius:10px;background:#fff;min-width:150px;min-height:38px}
.hwq__mark{font-family:var(--font-heading-th);font-size:13px;font-weight:700}
.hwq__row.ok{background:rgba(30,142,90,.10)}.hwq__row.ok .hwq__mark{color:#1E8E5A}
.hwq__row.bad{background:rgba(214,69,65,.10)}.hwq__row.bad .hwq__mark{color:#C0392B}
.hwq__opt.ok{border-color:#1E8E5A;background:rgba(30,142,90,.14)}
.hwq__opt.bad{border-color:#C0392B;background:rgba(214,69,65,.14);text-decoration:line-through}
.hwq__opt.key{box-shadow:0 0 0 2px rgba(30,142,90,.55)}
@media (max-width:640px){.hw-quiz{margin:6px 10px 14px;padding:12px 10px 4px}.hwq__lbl{min-width:0}.hwq__sel{min-width:130px}}

/* 🔒 structure-drill page whose hub card is_locked (reading-homework-structure.js lockedGate) */
.hw-locked{margin:24px auto;max-width:520px;padding:28px 24px;text-align:center;border:1.5px dashed var(--color-border);border-radius:16px;background:var(--color-soft-bg);font-family:var(--font-heading-th);font-size:18px;font-weight:700;color:var(--color-ink-soft);line-height:1.8}
.hw-locked small{display:block;font-size:13px;font-weight:500;margin-top:6px}