:root{font-family:"Noto Sans TC","Noto Sans CJK TC","PingFang TC","Microsoft JhengHei",sans-serif;color:#483d30;background:#fff8eb;--ink:#483d30;--green:#295d50;--mint:#c5e1cd;--wood:#d4aa75;--coral:#bd644b}*{box-sizing:border-box}body{margin:0;background-image:radial-gradient(#a48e6720 .7px,transparent .7px);background-size:15px 15px}h1,h2,h3,p{margin:0}p{line-height:1.75}button,input,textarea,summary{font:inherit;color:inherit}button,a,summary{min-height:44px}button{border:1.5px solid #aebc9e;border-radius:11px 14px 12px 10px;padding:11px 16px;background:#fffdf6;cursor:pointer;line-height:1.45}button:hover:not(:disabled):not(.drag-handle){background:#e8f0dc}button:disabled{opacity:.5;cursor:not-allowed}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,summary:focus-visible,[tabindex]:focus-visible{outline:3px solid #be683c;outline-offset:4px}.primary{background:#c5e1cd;border:2px solid #48765f;font-weight:800}.danger{border-color:#bb8d72;color:#8b452d}a{color:inherit;text-decoration:none}.site-header{max-width:1240px;margin:auto;padding:18px 28px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #d8d0b9}.brand{display:flex;align-items:center;gap:12px;font-size:18px;font-weight:850}.brand span{font-size:12px;letter-spacing:.1em;border-left:1px solid #a9946e;padding-left:12px}.private-tag{font-size:12px;color:#746b54}.intro{padding:39px 0 30px}.eyebrow{font-size:12px;font-weight:800;letter-spacing:.14em;color:#7e775d;margin-bottom:8px}h1{font-size:clamp(29px,4vw,44px);letter-spacing:.04em;line-height:1.3}.intro>p:not(.eyebrow){font-size:17px;color:#736a55;margin-top:11px}.conditions{display:flex;flex-wrap:wrap;gap:12px;margin-top:18px;font-size:13px}.conditions span{background:#f4ecd8;border-radius:6px;padding:5px 10px}.mobile-br{display:none}main{max-width:1200px;margin:auto;padding:0 28px}.teacher-card{display:flex;align-items:center;gap:22px;background:#eaf0de;border:1.5px solid #c3cbb0;border-radius:20px 24px 18px 22px;padding:16px 24px 0 15px;margin-bottom:24px;position:relative}.teacher-crop{flex:0 0 112px;height:155px;overflow:hidden;align-self:flex-end}.teacher-crop img{width:112px;height:auto;display:block}.teacher-copy{padding-bottom:18px;flex:1;min-width:0}.teacher-copy h2{font-size:22px;line-height:1.45}.teacher-copy :is(.guide-live,.guide-reserve)>p:not(.eyebrow){font-size:15px;margin-top:8px}.teacher-copy .guide-note{color:#6e7055;font-size:13px!important}.steps{padding:0;margin:0 0 18px;list-style:none;display:flex;gap:10px;flex-shrink:0}.steps li{display:flex;align-items:center;flex-direction:column;gap:5px;font-size:12px;color:#7e826a;padding:9px}.steps span{display:grid;place-items:center;border:1px solid #acb89b;border-radius:50%;width:30px;height:30px;font-weight:800}.steps .current{color:#244e40;background:#d2e1bd;border-radius:10px}.steps .done span{background:#486d54;color:#fff}.workspace{display:grid;grid-template-columns:minmax(0,1.75fr) minmax(260px,1fr);gap:23px;align-items:start}.lab-card,.notebook,.compare-card{background:#fffdf7;border:1.5px solid #d2c6a9;border-radius:19px 23px 18px 21px;padding:23px;box-shadow:0 3px 0 #ded1b550;min-width:0}.lab-heading{display:flex;align-items:center;justify-content:space-between;gap:10px}.lab-heading h2{font-size:23px}.pill{background:#e8eddb;border:1px solid #d5dec4;padding:6px 9px;border-radius:7px;font-size:12px;white-space:nowrap}.bench-caption{font-size:13px;color:#746950;margin:12px 0 4px}.bench{height:330px;position:relative;isolation:isolate;margin:0 -5px}.bench svg{width:100%;height:100%;display:block;overflow:visible}.drag-handle{position:absolute;transform:translate(-50%,-50%);padding:0;width:44px;height:44px;border:2px solid #3b6e5d;border-radius:50%;background:#d9ebd0e6;box-shadow:0 0 0 4px #fffdf6b3;touch-action:none;cursor:grab;font-size:25px;line-height:1}.drag-handle.is-dragging{cursor:grabbing;background:#e8d99b}.drag-handle:disabled{opacity:.65;cursor:default}.readouts{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}.reading{padding:13px 8px;border-radius:10px;background:#f1f2df;text-align:center}.reading:nth-child(2){background:#faecd9}.reading:nth-child(3){background:#e8eee3}.reading>span{font-size:12px;display:block}.reading strong{font-size:28px;display:block;margin-top:5px;color:#31584c}.reading small{font-size:16px;font-weight:500}.direction-note{font-size:14px;margin:15px 0;color:#626149;min-height:1.75em}.move-actions{display:grid;grid-template-columns:1fr 1fr;gap:10px}.move-actions button{font-size:14px;font-weight:700}.keyboard-help{margin-top:10px;font-size:13px}.keyboard-help summary{padding:10px 0;cursor:pointer}.keyboard-help p{padding:0 0 10px;color:#716d59}.round-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:12px}.round-actions .primary{flex:1}.round-actions #redo{font-size:13px}.next-action{display:flex;justify-content:flex-end;margin-top:10px}.next-action button{border-color:#678a69;background:#edf3e1;font-weight:700}.feedback{font-size:14px;margin-top:10px;line-height:1.65}.feedback.error,.field-feedback.error{color:#9b462f}.feedback.good,.field-feedback.good{color:#2b694e}.notebook-heading{display:flex;align-items:center;gap:10px;margin-bottom:9px}.notebook-heading>span{font-size:28px;color:#748b64}.notebook h2{font-size:23px}.muted{font-size:13px;color:#79735f}.empty-note{text-align:center;padding:45px 8px;color:#91836b;font-size:14px}.record{border:1px dashed #bbbf9e;border-radius:12px;padding:16px;margin-top:18px;background:#f4f2df}.record.long{background:#eaf1e1}.record h3{font-size:17px}.record dl{margin:11px 0 0;display:grid;grid-template-columns:1fr auto;gap:8px;font-size:14px}.record dt,.record dd{margin:0}.record dd{font-weight:750}.save-status{font-size:13px;color:#716b54;margin:17px 0 8px}.notebook>button{font-size:13px}.compare-card{margin-top:25px;padding:28px}.compare-card h2{font-size:27px}.compare-card h3{font-size:21px}.evidence-pair{display:grid;grid-template-columns:1fr 1fr;gap:16px;margin:18px 0}.evidence-pair .record{margin-top:0}.distance-choice{margin:22px 0 0;border:1px solid #c9ceb5;border-radius:11px;padding:16px;min-width:0}.distance-choice legend{font-weight:750;font-size:16px;padding:0 6px}.distance-choice>div{display:flex;gap:10px;flex-wrap:wrap}.distance-choice label{display:flex;gap:8px;align-items:center;padding:6px;min-height:44px;font-size:14px}.distance-choice input{width:19px;height:19px;margin:0}#work-form{margin-top:25px;border-top:1px solid #ddd7c4;padding-top:24px}#work-form>p{font-size:14px;margin-top:8px}.work-grid{display:grid;grid-template-columns:1fr 1fr;gap:18px;margin-top:18px}.work-grid fieldset{border:1px solid #c6ccb2;border-radius:12px;padding:17px;min-width:0}.work-grid legend{font-weight:800;padding:0 6px}.work-grid label{font-size:14px;display:block;font-weight:650}.work-grid label:not(:first-of-type){margin-top:14px}.input-unit{display:flex;align-items:center;gap:10px;margin-top:7px}.input-unit>span{font-weight:500}input:not([type=radio]):not([type=checkbox]),textarea{width:100%;min-width:0;border:1.5px solid #b6c4a6;border-radius:8px;padding:10px;background:#fffef9;min-height:44px;font-size:16px}.field-feedback{font-size:13px;line-height:1.5;margin-top:6px}.small-actions{display:flex;gap:10px;flex-wrap:wrap;margin-top:15px}.formula{margin-top:13px;background:#f8eed7;padding:16px;border:1px dashed #c5ae7b;border-radius:10px;font-size:14px;line-height:1.8}#explanation{margin-top:28px;border-top:1px solid #d7d5bd;padding-top:24px}#explanation>p{font-size:14px;margin-top:8px}#explanation>label{display:block;font-size:14px;font-weight:700;margin-top:17px}textarea{resize:vertical;line-height:1.7;margin:8px 0 12px}.revision{margin-top:14px;border-left:3px solid #a0b78c;padding:12px 14px;background:#f2f4e6;border-radius:0 9px 9px 0}.revision strong{font-size:12px}.revision p{font-size:14px;white-space:pre-wrap;overflow-wrap:anywhere}.completion{padding:20px;background:#e6efda;border:1px solid #b8c5a5;border-radius:12px;margin-top:20px}.completion p{font-size:14px;margin-top:7px}.completion summary{padding:12px 0;cursor:pointer}.record-management{margin-top:26px;color:#70654e}.record-management summary{padding:12px 0;cursor:pointer;font-size:14px}.record-management p{font-size:13px;margin:10px 0}.record-management button{font-size:13px}.alert{background:#fff0d9;border:2px solid #cc9b64;padding:20px;border-radius:14px;margin-bottom:23px}.alert h2{font-size:20px}.alert p{font-size:14px;margin-top:7px}footer{text-align:center;padding:35px 10px;color:#7b7d62}footer strong{font-size:15px}footer p{font-size:12px;margin-top:8px}dialog{max-width:min(520px,94vw);border:2px solid #a8b697;border-radius:18px;padding:24px;background:#fff8eb;color:var(--ink)}dialog::backdrop{background:#483d305e}dialog h2{font-size:22px;margin-bottom:14px}dialog p{font-size:15px;margin-bottom:15px}.confirm-label{display:flex;align-items:center;gap:10px;font-size:14px;margin:15px 0;min-height:44px}.confirm-label input{width:22px;height:22px;flex-shrink:0}.sr-only{position:absolute!important;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}[hidden]{display:none!important}
@media(max-width:900px){.workspace{grid-template-columns:1fr}.teacher-card{flex-wrap:wrap;gap:14px}.steps{width:100%;margin:0 0 16px;justify-content:center}.steps li{flex-direction:row;padding:5px 10px}.teacher-copy{flex-basis:calc(100% - 150px)}.notebook{padding:22px}.notebook #records{display:grid;grid-template-columns:1fr 1fr;gap:15px}.notebook .record{margin:12px 0 0}.notebook .empty-note{grid-column:1/-1;padding:20px}}
@media(max-width:600px){main{padding:0 13px}.site-header{padding:14px;gap:8px;flex-wrap:wrap}.brand{font-size:14px;gap:8px}.brand span{font-size:11px;padding-left:8px}.private-tag{font-size:10px}.intro{padding:27px 1px 23px}.intro>p:not(.eyebrow){font-size:15px}.mobile-br{display:block}.conditions{font-size:12px;gap:6px;margin-top:14px}.conditions span{padding:5px 8px}.teacher-card{padding:12px 12px 0 4px;margin-bottom:18px;gap:8px}.teacher-crop{flex-basis:70px;height:105px;align-self:center}.teacher-crop img{width:70px}.teacher-copy{flex:1;min-width:0;padding-bottom:8px}.teacher-copy h2{font-size:18px}.teacher-copy :is(.guide-live,.guide-reserve)>p:not(.eyebrow){font-size:14px;margin-top:6px}.teacher-copy .guide-note{font-size:12px!important}.eyebrow{font-size:10px;letter-spacing:.08em}.steps{margin:0 0 11px;gap:4px}.steps li{font-size:11px;padding:4px 7px}.steps span{width:23px;height:23px}.lab-card,.notebook{padding:18px 12px}.lab-heading h2{font-size:20px}.pill{font-size:10px;padding:6px}.bench{height:260px;margin:0 -3px}.bench-caption{font-size:12px}.readouts{gap:6px}.reading{padding:11px 3px}.reading>span{font-size:11px}.reading strong{font-size:24px}.reading small{font-size:16px}.move-actions{gap:7px}.move-actions button{font-size:13px;padding:11px 5px}.direction-note{font-size:13px}.round-actions button{font-size:14px;padding:11px 9px}.round-actions #redo{font-size:12px}.notebook h2{font-size:21px}.notebook #records{grid-template-columns:1fr}.record{padding:14px}.compare-card{padding:21px 14px}.compare-card h2{font-size:24px}.evidence-pair,.work-grid{grid-template-columns:1fr;gap:12px}.distance-choice{padding:12px}.distance-choice legend{font-size:15px}.distance-choice>div{display:block}.distance-choice label{font-size:14px}.work-grid fieldset{padding:14px}.small-actions button{font-size:14px}.conditions b{font-size:13px}dialog{padding:19px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation:none!important;transition:none!important}}

/* Physical ring lives in the scaled SVG; this fixed halo is only its touch target. */
.drag-handle{background:#cde2bf22;border:1px dashed #618064;box-shadow:none}.drag-handle span{opacity:0}.drag-handle.is-dragging{background:#e8d99b44}

/* Mobile readability refinement: preserve apparatus geometry and teacher artwork. */
@media(max-width:600px){
 .site-header{padding:10px 14px}
 .intro{padding:17px 1px 16px}
 .intro>.eyebrow{display:none}
 .intro h1{font-size:28px}
 .intro>p:not(.eyebrow){font-size:14px;margin-top:7px}
 .intro .mobile-br{display:none}
 .conditions{margin-top:10px}
 .conditions span{padding:4px 8px}
 .teacher-card{margin-bottom:14px}
 .reading>span{font-size:13px;line-height:1.5}
 .reading{padding:10px 3px}
 .bench-caption,.teacher-copy .guide-note{font-size:13px!important}
 .bench svg text{font-size:13px}
 .pill{font-size:12px}
}

/* Approved guide-height repair: intrinsic, wrapping reserves; never clip text.
   Invisible copies share the live grid cell, so all gesture states fit at any
   width or text size without moving the apparatus or issuing scroll calls. */
.teacher-copy{display:grid;grid-template-columns:minmax(0,1fr);overflow-anchor:none}
.guide-live,.guide-reserve{grid-area:1/1;min-width:0}
.guide-reserve{visibility:hidden;pointer-events:none;user-select:none}