@import url('notation-font.css');
/* Which C: the keyboard carries octave numbering, with compact notation below. */
.ct-notation #note-names .register-heading{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:8px 16px}
.ct-notation #note-names .register-heading h3{margin:0}
.ct-notation #note-names .register-audio{display:flex;gap:6px}
.ct-notation #note-names .register-audio button{font-size:14px;padding:6px 10px;min-height:44px}
.ct-notation #note-names [data-register-sound][aria-checked=true]{background:#edf2ed;border-color:#52694f;color:#30482e}
.ct-notation #note-names .middle-c-choice{border-bottom:3px solid #927044}
.ct-notation #note-names .middle-c-choice small{display:block;font:600 10px/1.2 system-ui;white-space:nowrap;margin-top:2px}
.ct-notation #note-names .register-keyboard{overflow-x:auto;overscroll-behavior-x:contain;margin:12px 0;scrollbar-color:#92754a #eee6d6}
.ct-notation #note-names .register-keyboard svg{width:100%;margin:0}
.ct-notation #note-names .register-readout{font-size:16px;margin:10px 0}
.ct-notation #note-names .register-staff{max-width:280px;padding:8px 10px;background:transparent;border:0}
.ct-notation #note-names .register-staff h4{font-size:14px}
.ct-notation #note-names .register-notation{align-items:flex-end;gap:16px}
.ct-notation #note-names .register-staff .notation{max-width:260px;margin:4px auto}
.ct-notation #note-names .register-staff button{min-height:44px;padding:6px 10px}
.ct-notation #note-names .controls{justify-content:center;margin-bottom:0}
@media(max-width:480px){.ct-notation #note-names .register-keyboard svg{min-width:680px}.ct-notation #note-names .register-notation{gap:6px}.ct-notation #note-names .register-staff{padding:4px 0}.ct-notation #note-names .register-readout{text-align:left}}
.ct-notation{--ink:#2F323A;--paper:#FBF4E4;--blue:#1C3A5A;--wine:#713D2F;--gold:#D1A866}.ct-notation *{box-sizing:border-box}.ct-notation h3{font-size:25px;line-height:1.3;margin:0 0 14px}.ct-notation .sec-num{display:block;font:14px/1.6 system-ui;color:var(--wine)}.ct-notation a{color:var(--blue);text-underline-offset:4px}.ct-notation button,.ct-notation select,.ct-notation input{font:16px system-ui}.ct-notation button,.ct-notation select{min-height:44px;border:1px solid var(--blue);border-radius:5px;padding:9px 14px;background:white;color:var(--blue)}.ct-notation button{cursor:pointer}.ct-notation button.primary,.ct-notation button[aria-pressed=true]{background:var(--blue);color:white}.ct-notation button:disabled{opacity:.45;cursor:default}.ct-notation button:hover:not(:disabled){box-shadow:0 0 0 2px var(--gold)}.ct-notation :focus-visible{outline:3px solid var(--wine);outline-offset:4px}.ct-notation img{max-width:100%;height:auto}.ct-notation .chapter-image{margin:32px 0}.ct-notation .chapter-image img{width:100%}.ct-notation figcaption,.ct-notation .small,.ct-notation .review-note{font:14px/1.5 system-ui}.ct-notation .review-note{background:#fff;border-left:4px solid var(--gold);padding:12px 16px}.ct-notation .box-persona{padding:16px 22px;border-left:4px solid #5F7D6B;background:#fff}.ct-notation .box-label{font:600 14px system-ui}.ct-notation .breath{border:0;border-top:1px solid #b9b5ab;margin:36px 0}.ct-notation .learning{background:#fff;border:1px solid #b4bbc3;border-top:4px solid var(--blue);padding:24px;margin:32px 0;scroll-margin-top:20px}.ct-notation .learning p{margin:12px 0}.ct-notation .learning .intro{font:17px/1.55 system-ui}.ct-notation .controls{display:flex;gap:10px;flex-wrap:wrap;align-items:center;margin:14px 0}.ct-notation .controls label{font:16px system-ui;display:flex;gap:8px;align-items:center}.ct-notation .notation{display:block;width:100%;height:auto;color:var(--ink);touch-action:pan-x pan-y}.ct-notation .notation text{font-family:system-ui}.ct-notation .notation .music-glyph{font-family:Bravura}.ct-notation .notation .chosen{fill:var(--blue)}.ct-notation .staff-slider{width:100%;min-height:44px;accent-color:var(--blue)}.ct-notation .note-readout{font:600 19px/1.5 system-ui;min-height:29px}.ct-notation .feedback{font:16px/1.5 system-ui;min-height:48px;padding:12px;background:#f1f3f5;border-left:3px solid var(--blue)}.ct-notation .feedback.correct{border-color:#2F4F43;background:#edf4ef}.ct-notation .two-up{display:grid;grid-template-columns:1fr 1fr;gap:18px}.ct-notation .octave-example{border:1px solid #b4bbc3;padding:12px}.ct-notation .octave-example h4{font:600 17px system-ui;margin:8px 0}.ct-notation .quiz-options{display:flex;flex-wrap:wrap;gap:10px}.ct-notation .quiz-question{padding:20px 0;border-top:1px solid #b4bbc3}.ct-notation .quiz-question h4{font:600 18px/1.5 system-ui;margin:0 0 12px}.ct-notation .practice-box{border-top:4px solid var(--wine);margin-top:40px;padding-top:22px}.ct-notation ct-keyboard{display:block;margin-top:18px;max-width:100%}.ct-notation .sound-status{font:14px system-ui;min-height:20px}.ct-notation .playing{outline:3px solid var(--gold)}@media(max-width:560px){.ct-notation .learning{padding:16px}.ct-notation .two-up{grid-template-columns:1fr}.ct-notation .controls button{flex-grow:1}.ct-notation .notation{min-width:0}}@media(prefers-reduced-motion:reduce){}.ct-notation .staff-display .notation{max-width:600px;margin-inline:auto}.ct-notation .section-heading{scroll-margin-top:20px}.ct-notation button.chosen-wrong{background:white;color:var(--wine);border:2px dashed var(--wine)}.ct-notation button.chosen-right{background:#2F4F43;border-color:#2F4F43;color:white}.ct-notation .tone-grid,.ct-notation .name-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:12px}.ct-notation .tone-card,.ct-notation .name-card{min-width:0;border:1px solid #bac3cd;background:#fafbf9;padding:12px;display:flex;flex-direction:column}.ct-notation .tone-card h4,.ct-notation .name-card h4{font:700 19px/1.4 system-ui;margin:0}.ct-notation .tone-card .small,.ct-notation .name-card .small{min-height:42px}.ct-notation .tone-card button,.ct-notation .name-card button{margin-top:auto;width:100%}.ct-notation .wave-display svg{width:100%;display:block;height:auto}.ct-notation .wave-display text{font:20px system-ui;fill:var(--ink)}.ct-notation .wave-explanation{font:16px/1.6 system-ui}.ct-notation .tone-card:has(.playing){box-shadow:0 0 0 3px var(--gold)}.ct-notation .name-sequence{font:600 17px/1.7 system-ui;padding:10px;background:#edf2f5;overflow-wrap:anywhere}.ct-notation .learning details{font:16px/1.6 system-ui;border-top:1px solid #bac3cd;padding-top:12px}.ct-notation .learning summary{cursor:pointer;font-weight:600;min-height:44px}.ct-notation .name-card .notation{margin-block:8px}.ct-notation #note-names h4{font-family:system-ui}.ct-notation #hear-timbre .controls label{flex-wrap:wrap}.ct-notation #wave-axis{max-width:100%}@media(max-width:650px){.ct-notation .tone-grid,.ct-notation .name-grid{grid-template-columns:1fr}.ct-notation .tone-card .small,.ct-notation .name-card .small{min-height:0}.ct-notation .name-card .notation{max-width:260px;margin-inline:auto}.ct-notation .wave-display{max-width:420px;width:100%;margin-inline:auto}}.ct-notation .register-keyboard svg{display:block;width:100%;margin:14px 0 8px}.ct-notation .register-choices{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));gap:5px}.ct-notation .register-choices button{padding:9px 2px;font-weight:650}.ct-notation .register-readout{text-align:center;font:600 18px/1.45 system-ui}.ct-notation .register-notation{display:flex;justify-content:center;gap:12px}.ct-notation .register-staff{min-width:0;max-width:360px;width:100%;border:1px solid #b4bbc3;padding:12px;background:#fafbf9}.ct-notation .register-staff h4{margin:0;font:600 16px system-ui}.ct-notation .register-staff button{width:100%}.ct-notation .register-staff .notation{margin-block:0}.ct-notation .middle-c-pair .register-staff{width:50%}.ct-notation .boundary-keys{display:grid;grid-template-columns:repeat(3,1fr);grid-template-rows:28px 92px;position:relative;width:min(290px,100%);margin:16px auto 0;gap:0}.ct-notation .octave-band{font:600 13px/28px system-ui;text-align:center}.ct-notation .band-three{grid-column:1;background:#dbe6ee}.ct-notation .band-four{grid-column:2/4;background:#efe0b9}.ct-notation .boundary-keys button{border-radius:0;align-items:flex-end;justify-content:center;display:flex;gap:1px;padding-bottom:10px;color:var(--ink);border-color:#687481;box-shadow:none}.ct-notation .boundary-keys button.boundary-selected{background:#efe0b9}.ct-notation .boundary-black{position:absolute;top:28px;left:calc(66.667% - 13px);width:26px;height:48px;background:#26323e;border-radius:0 0 3px 3px;pointer-events:auto}.ct-notation .boundary-keys strong{color:var(--wine)}.ct-notation .proposed-prose{scroll-margin-top:20px}.ct-notation .learning .sound-status:empty{min-height:0;margin:0}.ct-notation .tone-card .small{min-height:0}.ct-notation .tone-card .wave-display{margin-top:8px}.ct-notation #note-names>h4{font-size:18px;margin-bottom:8px}@media(max-width:480px){.ct-notation .register-choices{grid-template-columns:repeat(4,minmax(0,1fr))}.ct-notation .register-staff{padding:7px}.ct-notation .register-notation{gap:8px}.ct-notation .register-staff h4{font-size:14px}.ct-notation .register-staff button{font-size:14px;padding:8px 2px}.ct-notation .register-readout{font-size:16px}}.ct-notation .pedantry{margin:28px 0 34px;border:1px solid #c8b795;border-left:5px solid var(--wine);background:#f7efe0;scroll-margin-top:20px;border-radius:0 7px 7px 0}.ct-notation .pedantry summary{display:grid;grid-template-columns:30px minmax(0,1fr) 18px;align-items:center;gap:12px;list-style:none;cursor:pointer;padding:16px 18px;min-height:64px}.ct-notation .pedantry summary::-webkit-details-marker{display:none}.ct-notation .pedantry summary:hover{background:#efe3ca}.ct-notation .pedantry-label{display:block;font:650 13px/1.5 system-ui;color:var(--wine);margin-bottom:3px}.ct-notation .pedantry-title{display:block;font:600 20px/1.35 Georgia,serif}.ct-notation .pedantry-icon{font:26px/1 Georgia,serif;color:var(--wine)}.ct-notation .pedantry-chevron{font:30px/1 system-ui;color:var(--wine);transform-origin:center}.ct-notation .pedantry[open] .pedantry-chevron{transform:rotate(90deg)}.ct-notation .pedantry[open] summary{border-bottom:1px solid #d4c4a7}.ct-notation .pedantry-body{padding:4px 22px 12px;font-size:17px;line-height:1.65}.ct-notation .pedantry-body p{margin:14px 0}.ct-notation .pedantry-body p:last-child{margin-bottom:6px}@media(max-width:480px){.ct-notation .pedantry summary{padding:13px 12px;gap:9px;grid-template-columns:24px minmax(0,1fr) 16px}.ct-notation .pedantry-title{font-size:18px}.ct-notation .pedantry-body{padding:3px 16px 12px}}.ct-notation #staff-explorer,.ct-notation #note-drill,.ct-notation #accidentals{padding:18px;margin-block:24px}.ct-notation #staff-explorer h3,.ct-notation #note-drill h3,.ct-notation #accidentals h3{margin-bottom:8px}.ct-notation #staff-explorer .intro,.ct-notation #note-drill .intro,.ct-notation #accidentals .intro{margin:6px 0 10px}.ct-notation .task:empty{display:none}.ct-notation .staff-workbench{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);align-items:center;gap:20px;margin:10px 0}.ct-notation .staff-workbench .staff-display .notation{width:100%;max-width:360px;margin:0 auto}.ct-notation .staff-controls{min-width:0}.ct-notation .staff-controls .note-readout{font-size:17px;line-height:1.4;margin:0 0 8px}.ct-notation .staff-controls label{display:block}.ct-notation .staff-controls .controls{gap:6px;margin:7px 0}.ct-notation .step-controls,.ct-notation .playback-controls,.ct-notation .accidental-choices{display:flex;flex-wrap:nowrap}.ct-notation .step-controls button,.ct-notation .playback-controls button,.ct-notation .accidental-choices button{flex:1;white-space:nowrap;padding:8px 9px}.ct-notation .staff-workbench .sound-status:empty{display:none}.ct-notation #staff-explorer ct-keyboard,.ct-notation #accidentals ct-keyboard{margin-top:10px}.ct-notation #staff-explorer>.small,.ct-notation #accidentals>.small{margin:8px 0 0}.ct-notation #staff-explorer>a{display:inline-block;margin-top:8px}.ct-notation .staff-controls .staff-slider{display:block}.ct-notation .accidental-choices button{font-size:17px}@media(max-width:620px){.ct-notation .staff-workbench{grid-template-columns:1fr;gap:8px;margin:6px 0}.ct-notation .staff-workbench .staff-display .notation{max-width:300px}.ct-notation .staff-controls .note-readout{margin-bottom:4px}.ct-notation .staff-controls .controls{margin:5px 0}.ct-notation #staff-explorer,.ct-notation #note-drill,.ct-notation #accidentals{padding:14px}.ct-notation .staff-controls .playback-controls button{padding-inline:8px}}.ct-notation .practice-links{padding-left:24px}.ct-notation .practice-links li{margin:10px 0}
.ct-notation{font:19px/1.7 Georgia,serif;clear:both}.ct-notation .learning h3{font:700 25px/1.3 Georgia,serif;letter-spacing:normal}.ct-notation .learning a{font:14px/1.5 system-ui}.ct-notation .learning .tone-card{margin:0}.ct-notation .pedantry{float:none;width:auto;max-width:none;transform:none}.ct-notation .pedantry-body p{font:17px/1.65 Georgia,serif;text-indent:0}
/* Chapter 1.2 timbre comparison only: other notation/scale callers retain their layout. */
.ct-notation #hear-timbre .wave-display text{font:14px system-ui}
.ct-notation #hear-timbre{padding:18px;margin-block:24px}.ct-notation #hear-timbre h3{font-size:24px;margin-bottom:6px}.ct-notation #hear-timbre .intro{font:16px/1.5 system-ui;margin:0 0 12px}.ct-notation #hear-timbre .wave-display{max-width:560px;margin:0 auto 12px;border:1px solid #d1d8d8;border-radius:6px;background:#fafaf7;overflow:hidden}.ct-notation #hear-timbre .wave-display svg{display:block;width:100%;height:auto;font-family:system-ui}.ct-notation #hear-timbre .timbre-choices{display:grid;grid-template-columns:repeat(3,minmax(0,1fr)) auto;gap:8px;max-width:560px;margin:auto}.ct-notation #hear-timbre .timbre-choices button{font:16px/1.3 system-ui;min-height:44px;padding:8px 12px;white-space:nowrap}.ct-notation #hear-timbre .timbre-choices .playing{box-shadow:inset 0 -4px 0 #d1a866}.ct-notation #hear-timbre .timbre-description{font:14px/1.4 system-ui;margin:8px auto 0;max-width:560px}.ct-notation #hear-timbre .sound-status{font:14px/1.4 system-ui;min-height:20px;margin:2px auto 4px;max-width:560px}.ct-notation #hear-timbre .timbre-error{font:14px/1.4 system-ui;color:#713d2f;max-width:560px;margin:6px auto}.ct-notation #hear-timbre .timbre-error:empty{display:none}.ct-notation #hear-timbre .timbre-help{max-width:560px;margin:auto;font:16px/1.5 system-ui}.ct-notation #hear-timbre .timbre-help summary{cursor:pointer;min-height:44px;display:list-item;align-content:center}.ct-notation #hear-timbre .timbre-help .controls label{flex-wrap:wrap}.ct-notation #hear-timbre .timbre-help p{font:14px/1.5 system-ui}.ct-notation #hear-timbre .timbre-help select{max-width:100%}@media(max-width:480px){.ct-notation #hear-timbre{padding:14px}.ct-notation #hear-timbre h3{font-size:22px}.ct-notation #hear-timbre .timbre-choices{gap:6px}.ct-notation #hear-timbre .timbre-choices button{padding-inline:6px}}

/* Only the two-staff landmark figure; retain its original notation scale. */
figure.clef-landmarks .clef-stage{position:relative;max-width:660px;margin-inline:auto}
figure.clef-landmarks .clef-stage img{display:block;width:100%;height:auto;margin:0}
figure.clef-landmarks .clef-target{position:absolute;top:49.08%;width:26.97%;height:23.04%;min-width:44px;min-height:44px;transform:translate(-50%,-50%);padding:0;margin:0;border:2px solid transparent;border-radius:6px;background:transparent;box-shadow:none;cursor:pointer;touch-action:manipulation}
figure.clef-landmarks .clef-treble{left:27.12%}
figure.clef-landmarks .clef-bass{left:73.33%}
figure.clef-landmarks .clef-target:hover,figure.clef-landmarks .clef-target.pending,figure.clef-landmarks .clef-target.playing{border-color:#214e62;background:rgb(33 78 98 / 4%)}
figure.clef-landmarks .clef-target:focus-visible{outline:3px solid #80334b;outline-offset:3px}
figure.clef-landmarks .clef-cue,figure.clef-landmarks .clef-status,figure.clef-landmarks .clef-error{font:14px/1.5 system-ui,sans-serif;text-align:center;margin:4px 0}
figure.clef-landmarks .clef-cue{color:#53636e}
figure.clef-landmarks .clef-status{min-height:42px;color:#214e62}
figure.clef-landmarks .clef-error{color:#713d2f}
figure.clef-landmarks .clef-error:empty{display:none}

figure.octave-image .octave-image-stage{position:relative;max-width:660px;margin-inline:auto}
figure.octave-image .octave-image-stage img{display:block;width:100%;height:auto;margin:0}
figure.octave-image .octave-image-target{position:absolute;box-sizing:border-box;transform:translate(-50%,-50%);width:min(44px,12%);min-width:24px;height:44px;min-height:44px;padding:0;margin:0;border:2px solid transparent;border-radius:5px;background:transparent;box-shadow:none;cursor:pointer;touch-action:manipulation}
figure.octave-image .octave-image-target:hover,figure.octave-image .octave-image-target.pending,figure.octave-image .octave-image-target.playing{border-color:#214e62;background:rgb(33 78 98 / 4%);box-shadow:none}
figure.octave-image .octave-image-target:focus-visible{outline:2px solid #80334b;outline-offset:-2px}
figure.octave-image .octave-image-cue,figure.octave-image .octave-image-status,figure.octave-image .octave-image-error{font:14px/1.5 system-ui,sans-serif;text-align:center;margin:4px 0}
figure.octave-image .octave-image-cue{color:#53636e}
figure.octave-image .octave-image-status{min-height:42px;color:#214e62}
figure.octave-image .octave-image-error{color:#713d2f}
figure.octave-image .octave-image-error:empty{margin:0;min-height:0}
.ct-notation #octave-explorer button.octave-note{display:block;width:100%;min-height:44px;padding:0;border:2px solid transparent;border-radius:6px;background:transparent;box-shadow:none}
.ct-notation #octave-explorer button.octave-note:hover,.ct-notation #octave-explorer button.octave-note.playing{border-color:#214e62;box-shadow:none}
/* Compact staff explorer only: the drill and other notation retain their layout. */
.ct-notation #staff-explorer .explorer-workbench{display:grid;grid-template-columns:130px minmax(0,340px) 44px;justify-content:center;align-items:center;gap:12px;margin:10px auto 0}
.ct-notation #staff-explorer .explorer-clef{display:flex;flex-direction:column;gap:8px;min-width:0}
.ct-notation #staff-explorer .explorer-clef select,.ct-notation #staff-explorer .explorer-clef button{font-size:14px;padding-inline:8px;width:100%}
.ct-notation #staff-explorer .explorer-play{display:block;width:100%;max-width:340px;padding:0;border:0;background:transparent;color:var(--ink);border-radius:4px;min-width:0}
.ct-notation #staff-explorer .explorer-play:hover{box-shadow:none;background:#faf8f2}
.ct-notation #staff-explorer .explorer-play .staff-display{display:block}
.ct-notation #staff-explorer .explorer-play .notation{max-width:340px;margin:0;width:100%}
.ct-notation #staff-explorer .explorer-steps{display:flex;flex-direction:column;gap:6px}
.ct-notation #staff-explorer .explorer-steps button{width:44px;height:44px;padding:0;font-size:24px;line-height:1}
.ct-notation #staff-explorer .note-readout{font:600 18px/1.4 system-ui;text-align:center;margin:4px 0 10px;min-height:51px}
.ct-notation #staff-explorer .note-readout span{display:block}
.ct-notation #staff-explorer .explorer-note{font:14px/1.4 system-ui;text-align:center;margin:4px 0}
.ct-notation #staff-explorer .explorer-note:empty{margin:0;min-height:0}
.ct-notation #staff-explorer .sound-status{text-align:center;margin:4px 0;min-height:20px}
.ct-notation #staff-explorer .explorer-tools{display:flex;justify-content:center;align-items:flex-start;gap:12px;flex-wrap:wrap;position:relative}
.ct-notation #staff-explorer .explorer-tools details{border:0;padding:0;margin:0;font:14px/1.5 system-ui}
.ct-notation #staff-explorer .explorer-tools summary{display:flex;align-items:center;min-height:44px;padding:8px;gap:6px}
.ct-notation #staff-explorer .explorer-tools summary:before{content:'▸'}
.ct-notation #staff-explorer .explorer-tools details[open]{flex-basis:100%;order:1;min-width:0;width:100%;max-width:100%}
.ct-notation #staff-explorer .explorer-piano ct-keyboard{min-width:0;width:100%}
.ct-notation #staff-explorer .explorer-tools details[open] summary:before{content:'▾'}
.ct-notation #staff-explorer .explorer-tools details[open] summary{justify-content:center}
.ct-notation #staff-explorer .explorer-tools details[open] p{font:14px/1.5 system-ui}
.ct-notation #staff-explorer .explorer-help label{display:block}
@media(max-width:620px){.ct-notation #staff-explorer .explorer-workbench{grid-template-columns:minmax(0,340px) 44px;gap:8px}.ct-notation #staff-explorer .explorer-clef{grid-column:1/-1;flex-direction:row;justify-content:center}.ct-notation #staff-explorer .explorer-clef select,.ct-notation #staff-explorer .explorer-clef button{width:auto}.ct-notation #staff-explorer .explorer-play{grid-column:1}.ct-notation #staff-explorer .explorer-steps{grid-column:2}.ct-notation #staff-explorer .intro{font-size:15px}.ct-notation #staff-explorer h3{font-size:22px}}
/* Chapter1.2 accidentals: fixed staff position, compact adjacent choices. */
.ct-notation #accidentals .accidental-stage{display:grid;grid-template-columns:84px minmax(0,340px);gap:12px;justify-content:center;align-items:center;margin:10px auto 0}
.ct-notation #accidentals .accidental-choices{display:flex;flex-direction:column;gap:6px;margin:0}
.ct-notation #accidentals .accidental-choices button{min-width:44px;min-height:44px;padding:8px;font-size:16px;white-space:nowrap}
.ct-notation #accidentals .accidental-play{display:block;width:100%;max-width:340px;padding:0;border:0;border-radius:4px;background:transparent;color:var(--ink);min-width:0}
.ct-notation #accidentals .accidental-play:hover{box-shadow:none;background:#faf8f2}
.ct-notation #accidentals .accidental-play .staff-display{display:block}
.ct-notation #accidentals .accidental-play .notation{max-width:340px;width:100%;margin:0}
.ct-notation #accidentals .accidental-note-controls{display:flex;justify-content:center;min-height:44px;margin:8px 0}
.ct-notation #accidentals .accidental-note-controls label{display:flex;align-items:center;gap:8px;font:14px system-ui}
.ct-notation #accidentals .note-readout{position:relative;font:600 18px/1.4 system-ui;text-align:center;min-height:70px;margin:4px 0 10px}
.ct-notation #accidentals .accidental-pitch-text{display:flex;justify-content:center;align-items:center;min-height:44px}
.ct-notation #accidentals .accidental-description>.accidental-relation{display:block}
.ct-notation #accidentals [data-acc-spell]{position:absolute;top:0;left:calc(50% + 28px);width:64px;min-height:44px;padding:4px;font-size:14px;font-weight:400}
.ct-notation #accidentals .accidental-range{font:14px/1.4 system-ui;min-height:40px;margin:8px 0;text-align:center}
.ct-notation #accidentals .accidental-note{font:14px/1.4 system-ui;text-align:center;margin:4px 0}
.ct-notation #accidentals .accidental-note:empty{margin:0;min-height:0}
.ct-notation #accidentals .sound-status{min-height:20px;margin:4px 0;text-align:center}
.ct-notation #accidentals .accidental-tools{display:flex;flex-wrap:wrap;justify-content:center;align-items:flex-start;gap:10px}
.ct-notation #accidentals .accidental-auto{display:flex;align-items:center;gap:6px;font:14px/1.5 system-ui;min-height:44px;cursor:pointer}
.ct-notation #accidentals .accidental-auto input{width:18px;height:18px;accent-color:var(--blue)}
.ct-notation #accidentals .accidental-tools details{border:0;padding:0;margin:0;font:14px/1.5 system-ui;min-width:0}
.ct-notation #accidentals .accidental-tools summary{display:flex;align-items:center;min-height:44px;padding:8px;gap:6px}
.ct-notation #accidentals .accidental-tools summary:before{content:'▸'}
.ct-notation #accidentals .accidental-tools details[open]{flex-basis:100%;order:1;min-width:0;width:100%;max-width:100%}
.ct-notation #accidentals .accidental-tools details[open] summary:before{content:'▾'}
.ct-notation #accidentals .accidental-tools details[open] summary{justify-content:center}
.ct-notation #accidentals .accidental-tools details[open] p{font:14px/1.5 system-ui}
.ct-notation #accidentals .accidental-piano ct-keyboard{min-width:0;width:100%}
@media(max-width:620px){.ct-notation #accidentals .accidental-stage{gap:8px;grid-template-columns:76px minmax(0,340px)}.ct-notation #accidentals .intro{font-size:15px}.ct-notation #accidentals h3{font-size:22px}}
/* Chapter1.2 octave comparison: stable music scale, one shared surface. */
.ct-notation #octave-explorer{padding:18px;margin-block:20px}
.ct-notation #octave-explorer h3{margin-bottom:6px;font-size:24px}
.ct-notation #octave-explorer .intro{font:16px/1.4 system-ui;margin:4px 0 10px}
.ct-notation #octave-explorer .octave-toolbar{display:flex;justify-content:center;align-items:center;flex-wrap:wrap;gap:10px;margin:8px 0}
.ct-notation #octave-explorer .octave-toolbar label{display:flex;align-items:center;gap:8px;font:14px/1.4 system-ui}
.ct-notation #octave-explorer .octave-steps{display:flex;gap:6px}
.ct-notation #octave-explorer .octave-steps button{width:44px;height:44px;padding:0;font-size:24px}
.ct-notation #octave-explorer [aria-disabled=true]{opacity:.45;cursor:default}
.ct-notation #octave-explorer .two-up{gap:12px;align-items:start;max-width:692px;margin:auto}
.ct-notation #octave-explorer .octave-example{border:0;padding:0;min-width:0;text-align:center}
.ct-notation #octave-explorer .octave-example h4{font:600 14px/1.4 system-ui;margin:4px 0 0}
.ct-notation #octave-explorer .octave-note{display:block;width:100%;max-width:340px;margin:0 auto;padding:0;border:0;background:transparent;border-radius:4px;color:var(--ink)}
.ct-notation #octave-explorer .octave-note .notation{width:100%;max-width:340px;margin:0}
.ct-notation #octave-explorer .octave-note:hover{box-shadow:none;background:#faf8f2}
.ct-notation #octave-explorer .note-readout{font:600 17px/1.4 system-ui;text-align:center;min-height:24px;margin:6px 0}
.ct-notation #octave-explorer .sound-status{font:14px/1.4 system-ui;text-align:center;min-height:20px;margin:4px 0}
.ct-notation #octave-explorer .octave-tools{display:flex;justify-content:center;flex-wrap:wrap;gap:12px;align-items:flex-start}
.ct-notation #octave-explorer .octave-help{border:0;padding:0;margin:0;font:14px/1.5 system-ui;min-width:0}
.ct-notation #octave-explorer .octave-help summary{display:list-item;align-content:center;min-height:44px;padding:8px;cursor:pointer}
.ct-notation #octave-explorer .octave-help[open]{flex-basis:100%;order:1}
.ct-notation #octave-explorer .octave-help p{font:14px/1.5 system-ui;margin:8px 0}
details.octave-reference{margin:16px 0;font:14px/1.5 system-ui;border-block:1px solid #c8c9c5;padding:4px 0}
details.octave-reference>summary{min-height:44px;align-content:center;cursor:pointer;padding:8px}
details.octave-reference>figure{margin:8px 0}
@media(max-width:620px){.ct-notation #octave-explorer{padding:14px}.ct-notation #octave-explorer h3{font-size:22px}.ct-notation #octave-explorer .two-up{grid-template-columns:1fr;gap:4px}.ct-notation #octave-explorer .octave-toolbar{gap:6px}.ct-notation #octave-explorer .octave-toolbar label{gap:6px}.ct-notation #octave-explorer .octave-toolbar select{padding-inline:8px}}