/* A small, shared rack alongside the existing problem / solution layout. */
#app:has(.math-tools-rail){max-width:1320px}
.lesson-layout:has(>.math-tools-rail){grid-template-columns:minmax(0,1fr) minmax(0,1.1fr) 100px!important;align-items:start}
.math-tools-rail{position:sticky;top:16px;padding:12px 8px;border-left:1px solid #d5dfed;background:#f4f6fa;text-align:center}
.math-tools-rail h2{font-size:13px;margin:0 0 10px;color:#52627a}
.math-tools-rail button{display:grid;place-items:center;gap:4px;width:100%;padding:10px 5px;font-size:12px;border-color:#b8c8e5}
.math-tools-rail button span{font-size:23px;line-height:1.3;color:#304f93}
.math-tools-rail p{font-size:11px;color:#626b80;line-height:1.65;margin:10px 0 0}
.expression-tool-dialog{width:min(850px,calc(100vw - 28px));max-width:850px;max-height:90vh;padding:24px;background:#fff;color:#17253a}
.expression-tool-dialog::backdrop{background:#17253a70}
.expression-tool-heading{display:flex;align-items:start;justify-content:space-between;gap:15px;padding-bottom:14px;border-bottom:1px solid #d5dfed}
.expression-tool-heading h2{margin:0;font-size:24px}
.expression-tool-heading p{font-size:13px;color:#626b80;margin:4px 0 0}
.expression-tool-source{display:flex;align-items:center;gap:8px;flex-wrap:wrap;margin:16px 0}
.expression-tool-source label{font-size:13px;font-weight:700}
.expression-tool-source select{flex:1;min-width:120px;max-width:100%;padding:8px;border:1px solid #cbd6e7;border-radius:6px}
.expression-board{display:flex;align-items:center;justify-content:center;gap:10px;flex-wrap:wrap;min-height:130px;padding:24px 16px;background:#f4f7fc;border-top:3px solid #304f93;border-bottom:1px solid #d5dfed;font-size:23px;overflow-wrap:anywhere}
.expression-term-group{display:inline-flex;gap:5px;align-items:center;flex-wrap:wrap}
.expression-term{font-size:22px;padding:6px 10px;border:1px solid #c7d3e7;background:#fff}
.expression-term[aria-pressed=true]{background:#e2edff;border:2px solid #304f93}
.expression-relation{padding:0 8px}
.expression-term-group .coefficient-action{padding:4px 7px;min-height:30px;font-size:12px;color:#26765b;border-color:#9fc4b3;background:#edf7f1}
.expression-tool-status{min-height:24px;font-size:13px;color:#79531c;margin:10px 0}
.expression-conditions{font-size:12px;color:#52627a;margin:8px 0 0}
.expression-tool-actions{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:18px}
.expression-tool-dialog button{font-size:14px}
.expression-tool-dialog .expression-term{font-size:22px}
.expression-tool-dialog .coefficient-action{font-size:12px}
.expression-both-sides{padding:14px 0;border-top:1px solid #d5dfed}
.expression-both-sides h3,.expression-operation-history h3{font-size:15px;margin:0 0 8px}
.expression-both-sides>div{display:flex;gap:8px;flex-wrap:wrap}
.expression-both-sides select,.expression-both-sides input{padding:8px;border:1px solid #cbd6e7;border-radius:6px;max-width:100%}
.expression-both-sides input{width:150px}
.expression-edit{margin:4px 0 18px;font-size:13px;color:#52627a}
.expression-edit summary{cursor:pointer;padding:6px 0}
.expression-edit label{display:block;margin:8px 0 5px}
.expression-edit textarea{width:100%;font:inherit;font-size:18px;padding:10px;border:1px solid #cbd6e7;border-radius:6px}
.expression-operation-history{padding-top:12px;border-top:1px solid #d5dfed}
.expression-operation-history ol{padding-left:24px;max-height:240px;overflow:auto;margin:0}
.expression-operation-history li{padding:6px 8px}
.expression-operation-history small{font-size:12px;color:#626b80}
.expression-operation-history p{font-size:18px;line-height:1.6;overflow-wrap:anywhere;margin:3px 0 0}
.expression-tool-footer{max-width:none;position:sticky;bottom:-24px;display:flex;justify-content:flex-end;gap:8px;flex-wrap:wrap;margin:14px 0 -2px;padding:14px 0 0;background:#fff;border-top:1px solid #d5dfed}
.expression-tool-result{padding:10px 12px;margin-top:16px;border-left:3px solid #26765b;background:#edf7f1}
.expression-tool-result small{display:block;color:#26765b;font-size:12px}
.expression-tool-result strong{font-size:18px;overflow-wrap:anywhere}
@media(max-width:1050px){.lesson-layout:has(>.math-tools-rail){grid-template-columns:minmax(0,1fr) minmax(0,1fr)!important}.math-tools-rail{grid-column:1/-1;grid-row:1;position:static;display:flex;align-items:center;gap:12px;padding:7px 10px;border:1px solid #d5dfed;border-radius:7px;text-align:left}.math-tools-rail h2{margin:0}.math-tools-rail button{display:flex;width:auto;gap:8px;padding:5px 12px}.math-tools-rail p{margin:0}.math-tools-rail br{display:none}}
@media(max-width:650px){.lesson-layout:has(>.math-tools-rail){grid-template-columns:minmax(0,1fr)!important}.expression-tool-dialog{padding:16px}.expression-tool-heading h2{font-size:21px}.expression-board{padding:18px 8px;font-size:19px}.expression-tool-dialog .expression-term{font-size:19px}.expression-tool-source select{flex-basis:100%}.expression-tool-footer{bottom:-16px}.math-tools-rail p{display:none}}

/* The working expression stays on one line; overflow scrolls horizontally. */
.expression-board{flex-wrap:nowrap;justify-content:flex-start;min-height:64px;padding:12px;overflow-x:auto;overflow-wrap:normal;white-space:nowrap}
.expression-board>*{flex-shrink:0}
.expression-term-group{flex-wrap:nowrap}
.expression-tool-dialog{width:min(1100px,calc(100vw - 28px));max-width:1100px;padding:16px}
.expression-tool-heading{align-items:center;padding-bottom:8px}
.expression-tool-heading>div{display:flex;align-items:center;gap:12px}
.expression-tool-heading h2{font-size:20px}
.expression-tool-source{margin:10px 0}
.expression-tool-actions{margin-bottom:8px}
.expression-both-sides{display:flex;align-items:center;gap:12px;padding:8px 0}
.expression-both-sides h3{margin:0;white-space:nowrap}
.expression-both-sides>div{align-items:center}
.expression-operation-history summary{cursor:pointer;font-size:13px;color:#52627a}
.expression-tool-result{display:flex;align-items:center;gap:8px;flex-wrap:wrap}
.expression-tool-result button{font-size:15px;padding:6px 10px}
.expression-tool-footer{bottom:-16px;padding-top:8px}
#expressionSavedOperand{max-width:240px}

.expression-tool-dialog{width:min(980px,calc(100vw - 24px));padding:12px;border:1px solid #cbd6e7;border-radius:10px}
.expression-inline{display:flex;align-items:center;gap:6px;flex-wrap:nowrap;overflow-x:auto;margin:0}
.expression-drag-handle{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:-12px -12px 10px;padding:10px 12px;background:#edf2fa;border-bottom:1px solid #cbd6e7;cursor:grab;user-select:none;touch-action:none;font-size:14px}
.expression-drag-handle span{font-size:12px;color:#53647e}
.expression-tool-dialog.is-dragging,.expression-tool-dialog.is-dragging .expression-drag-handle{cursor:grabbing}
.expression-inline label{font-size:13px;font-weight:700;white-space:nowrap}
.expression-inline input{flex:1;min-width:100px;width:100%;padding:9px;border:1px solid #b8c8e5;border-radius:6px;font-size:20px}
.expression-inline button{flex-shrink:0;white-space:nowrap;padding:8px;font-size:13px}
.expression-tool-status:empty{display:none}
.expression-tool-dialog #expressionSavedOperand{margin-top:8px;padding:5px}

.expression-manipulations{display:flex;align-items:center;gap:6px;flex-wrap:wrap;margin:8px 0}
.expression-manipulations label{font-size:13px}
.expression-manipulations input{width:65px;padding:6px}
.expression-manipulations select{max-width:240px;padding:6px}
.expression-tool-dialog .expression-board{margin-top:8px;min-height:50px;padding:8px}

.math-tools-rail .open-reduction-tool{margin-top:8px}
.reduction-tool-dialog{width:min(650px,calc(100vw - 28px));max-width:650px;padding:20px}
.reduction-tool-dialog header{display:flex;align-items:center;justify-content:space-between;gap:10px}
.reduction-tool-dialog h2{font-size:21px;margin:0 0 12px}
.reduction-tool-dialog select{max-width:100%;padding:8px}
.reduction-original{font-size:20px!important;font-weight:700;overflow-wrap:anywhere}
.reduction-fraction{background:#f4f6fc;padding:10px 16px;border-radius:8px}
.reduction-factor-row{display:flex;align-items:center;gap:12px;flex-wrap:wrap;padding:14px 0}
.reduction-factor-row+section{border-top:2px solid #304f93}
.reduction-factor-row>b{font-size:13px;color:#52627a}
.reduction-number{font-size:22px;font-weight:700}
.reduction-factors{display:flex;align-items:center;gap:6px;flex-wrap:wrap}
.reduction-factors button{font-size:20px;min-width:42px;padding:6px}
.reduction-factors button[aria-pressed=true]{background:#e2edff;border:2px solid #304f93}
.reduction-status{min-height:24px;color:#52627a}
.reduction-actions{display:flex;gap:8px;flex-wrap:wrap}

.reduction-prime-work{flex-basis:100%;padding-left:38px}
.reduction-prime-work ol{margin:4px 0;padding-left:22px;font-size:18px;line-height:1.7}
.reduction-prime-work p{font-size:18px;margin:6px 0}
.reduction-prime-options{display:flex;align-items:center;gap:6px;flex-wrap:wrap}
.reduction-prime-options span{font-size:13px}
.reduction-prime-options button{font-size:17px;padding:6px 12px}

/* Numerator on the left, denominator on the right. */
.reduction-tool-dialog{width:min(900px,calc(100vw - 28px));max-width:900px}
.reduction-fraction{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:0;padding:0}
.reduction-factor-row{display:flex;align-content:start;align-items:center;gap:10px;min-width:0;padding:16px}
.reduction-factor-row+section{border-top:0;border-left:2px solid #304f93}
.reduction-factor-row>b{flex-basis:100%;font-size:16px}
.reduction-prime-work{min-width:0;padding-left:0;overflow-wrap:anywhere}
.reduction-prime-work ol{font-size:17px}
@media(max-width:650px){.reduction-factor-row{padding:10px;gap:6px}.reduction-number{font-size:20px}.reduction-prime-work ol{font-size:15px;padding-left:18px}.reduction-prime-work p{font-size:15px}.reduction-prime-options button{font-size:15px;padding:5px 8px}}

.reduction-factor-product{font-size:20px;font-weight:700;overflow-wrap:anywhere}
.reduction-place{margin-top:14px}
.reduction-cancel-fraction{margin-top:16px;padding:14px;background:#f4f6fc;border-radius:8px}
.reduction-cancel-fraction h3{font-size:15px;margin:0 0 12px;color:#52627a}
.reduction-written-fraction{width:fit-content;max-width:100%;margin:auto}
.reduction-written-row{display:flex;align-items:center;gap:14px;padding:12px 8px}
.reduction-written-row+div{border-top:2px solid #304f93}
.reduction-written-row small{font-size:13px;color:#52627a;flex-shrink:0}
.reduction-written-row .reduction-factors{justify-content:center;flex:1}

.open-decimal-tool{margin-top:8px}.decimal-tool-dialog{max-width:760px}.decimal-tool-top,.decimal-tool-actions{display:flex;align-items:center;justify-content:space-between;gap:8px;flex-wrap:wrap}.decimal-tool-top select{padding:7px;max-width:100%}.decimal-tool-rows{max-height:220px;overflow:auto;padding-left:28px;line-height:1.9}.decimal-tool-summary,.decimal-saved-result{padding:10px;background:#eef6f0;border-radius:6px;overflow-wrap:anywhere}.decimal-saved-result{font-size:13px!important}

.open-fraction-tool{margin-top:8px}.open-fraction-tool>span{font-size:17px!important}.fraction-tool-dialog{max-width:800px}.fraction-tool-top,.fraction-source-form{display:flex;gap:10px;align-items:center;justify-content:space-between;flex-wrap:wrap}.fraction-tool-top>span{font-size:13px}.fraction-source-form{padding:12px 0;justify-content:flex-start}.fraction-source-form label{display:grid;gap:4px;font-size:12px}.fraction-source-form input{width:120px;padding:7px;border:1px solid #b8c8e5;border-radius:5px}.fraction-power-options{display:grid;gap:8px;margin:12px 0}.fraction-power-options button{text-align:left}.fraction-power-options button[aria-pressed="true"]{border:2px solid #287653;background:#e4f3eb;color:#155436;font-weight:700}.fraction-work{padding:10px 14px;background:#f1f5fa;margin:10px 0;overflow-wrap:anywhere}.fraction-saved-result{padding:10px;font-size:13px!important;background:#eef6f0;overflow-wrap:anywhere}

/* Written long division: place values stay aligned across quotient and subtraction. */
.decimal-division-scroll{overflow:auto;max-height:380px;padding:20px 14px;margin:12px 0;background:#fff;border:1px solid #d5deeb;border-radius:6px}
.decimal-written-division{--division-cell:1.35em;display:grid;grid-template-columns:max-content max-content;grid-template-rows:auto auto auto;column-gap:0;justify-content:start;font-family:Consolas,'Courier New',monospace;font-size:27px;line-height:1.4;width:max-content;min-width:240px;margin:0 auto}
.division-quotient-label{grid-column:1;grid-row:1;align-self:center;text-align:right;font:13px sans-serif;color:#53647e;padding-right:16px}
.division-quotient-written{grid-column:2;grid-row:1;display:grid;padding:8px 12px;color:#244f93;min-height:52px}
.division-divisor-written{grid-column:1;grid-row:2;display:flex;align-items:center;justify-content:flex-end;gap:12px;padding:10px 12px 0 0}
.division-divisor-written small{font:12px sans-serif;color:#53647e;white-space:nowrap;line-height:1.5}
.division-divisor-written b{font-weight:500}
.division-dividend-written{grid-column:2;grid-row:2;display:grid;border-top:2px solid #23354d;border-left:2px solid #23354d;border-top-left-radius:12px;padding:10px 12px 0}
.division-digit{text-align:center;min-width:0}.division-point{text-align:center}.division-zero{color:#66758c}
.division-work-written.decimal-tool-rows{grid-column:2;grid-row:3;padding:0 12px;margin:0;max-height:none;overflow:visible;line-height:1.4}
.division-written-line{position:relative;display:grid;min-height:38px}
.division-minus{position:absolute;left:-18px;top:0;color:#23354d}
.division-subtrahend{color:#53647e}.division-written-rule{max-width:100%;border-top:2px solid #53647e;margin:1px 0 2px}
.division-remainder{color:#176346;font-weight:700}.division-brought-down{color:#244f93;padding-top:10px}
.division-repeat-digit{text-decoration:overline;text-decoration-thickness:2px;text-underline-offset:3px;color:#176346}
@media(max-width:550px){.decimal-written-division{font-size:23px;min-width:200px}.decimal-division-scroll{padding:12px 4px}.division-divisor-written small{display:none}.decimal-tool-actions button{flex-grow:1}}

.expression-entry-controls{display:flex;align-items:center;flex-wrap:wrap;gap:6px;margin:10px 0;padding:10px;background:#f4f7fc;border:1px solid #d5dfed;border-radius:8px}
.expression-entry-controls label{display:flex;align-items:center;gap:6px;font-size:13px}
.expression-entry-controls input{width:90px;min-width:0;padding:5px 8px;border:1px solid #b8c8e5;border-radius:5px}
.expression-entry-controls button{min-height:32px;padding:4px 10px}
.expression-clear-row{display:flex;justify-content:flex-start;margin:6px 0}
.expression-clear-row button{min-height:32px;padding:4px 10px;color:#9d174d;background:#fce7f3;border-color:#f0a8c5}
.expression-calculated-result{padding:10px;border-left:3px solid #287653;background:#edf7f1;overflow-wrap:anywhere}

.expression-number-pad{display:grid;grid-template-columns:repeat(3,52px);gap:5px;width:fit-content;margin:8px 0 12px;padding:8px;border:1px solid #d5dfed;border-radius:8px;background:#f4f7fc}
.expression-number-pad button{min-height:36px;padding:5px;font-size:16px;text-align:center}
.expression-number-pad [data-number-clear]{grid-column:1/-1;font-size:13px;min-height:30px}

.expression-line-editor{display:flex;align-items:center;gap:8px;overflow-x:auto;padding:6px;margin:10px 0 0;border:2px solid #bccbe1;border-radius:8px;background:#fff;min-height:54px}
.expression-drop-side{display:flex;align-items:center;gap:4px;flex:1 0 auto;min-width:90px;min-height:40px;padding:4px 8px;border:1px dashed transparent;border-radius:6px}
.expression-drop-side.is-drop-target{background:#e4f3eb;border-color:#287653}
.expression-whole-term{white-space:nowrap;font-size:20px!important;padding:5px 9px;cursor:grab;border:1px solid #c7d3e7;border-radius:5px;background:#f4f7fc;user-select:none}
.expression-whole-term:active{cursor:grabbing}.expression-whole-term.is-dragging-term{opacity:.4}
.expression-drag-relation{font-size:22px;padding:0 6px}.expression-drag-guide{font-size:12px;color:#52627a;margin:5px 0 12px}

.expression-calculated-result small{display:block;color:#52627a;font-size:12px}.expression-calculated-result p{margin:4px 0}.expression-before-result{font-size:14px;color:#52627a}.expression-after-result{font-size:20px;color:#155436}

.expression-single-input{flex:1;min-width:200px}
.expression-single-input #expressionInput{width:100%;box-sizing:border-box}
.expression-inline .expression-line-editor{margin:0;min-height:42px;padding:3px 8px;gap:8px;overflow-x:auto;box-sizing:border-box}
.expression-inline .expression-drop-side{flex:0 0 auto;min-width:36px;min-height:30px;padding:0 2px;gap:5px}
.expression-inline .expression-whole-term{font-size:18px!important;padding:4px 2px;border:0;background:transparent;box-shadow:none;font-weight:500}
.expression-inline .expression-whole-term:hover{background:#e7effb}
.expression-inline .expression-drag-relation{font-size:18px;padding:0 4px}
.expression-line-editor[hidden],#expressionInput[hidden]{display:none!important}
.expression-operation-note{font-size:13px;color:#287653;margin:8px 0}
.expression-factor-controls{display:flex;flex-wrap:wrap;gap:8px;margin:8px 0}
.expression-factor-choice{display:inline-flex;align-items:center;gap:5px;padding:5px 8px;background:#f4f7fc;border-radius:6px}
.expression-factor-choice small{font-size:12px;color:#52627a}.expression-factor-choice button{padding:3px 8px;min-height:28px}

.expression-both-operation{display:flex;align-items:center;flex-wrap:wrap;gap:7px;margin:10px 0;padding:9px 10px;background:#edf3ff;border:1px solid #bdcce5;border-radius:8px}.expression-both-operation label{display:flex;align-items:center;gap:6px;font-size:13px}.expression-both-operation input{width:160px;padding:6px 8px;border:1px solid #bdcce5;border-radius:5px}.expression-both-operation select{padding:6px;border:1px solid #bdcce5;border-radius:5px}.expression-both-operation button{padding:6px 10px;min-height:32px}

.expression-single-input{display:flex;align-items:center;gap:6px;border:2px solid #bccbe1;border-radius:8px;padding:3px 6px;min-height:48px;box-sizing:border-box;flex-wrap:wrap}
.expression-single-input #expressionInput{flex:1;min-width:120px;width:auto;border:0;box-shadow:none}
.expression-inline .expression-single-input .expression-line-editor{flex:1;min-width:180px;border:0;padding:0;background:transparent;box-shadow:none}
.expression-single-input .expression-inline-both{display:flex;align-items:center;gap:4px;flex-wrap:nowrap;margin:0;padding:3px 0 3px 7px;border:0;border-left:1px solid #d5dfed;border-radius:0;background:transparent}
.expression-inline-both select{width:42px;padding:5px 2px}
.expression-inline-both input{width:76px;min-width:0;padding:5px 6px;font-size:14px}
.expression-inline-both button{white-space:nowrap;font-size:12px;padding:5px 7px;min-height:32px}

.expression-calculation-preview{margin:6px 0 0;padding:6px 12px;border-left:3px solid #287653;background:#edf7f1;border-radius:5px;overflow-x:auto}.expression-calculation-preview p{margin:3px 0;white-space:nowrap;line-height:1.5}.solution-stage-chip{display:inline-block;vertical-align:middle;padding:2px 8px;border-radius:12px;background:#edf0fa;color:#3c518f;font-size:12px;line-height:1.5;font-weight:700}.workshop .expression-redundant-result{display:none}

.workshop .expression-flow-source{margin-bottom:0}.expression-flow-source+.expression-calculation-preview{margin-top:0;border-top:1px solid #d1e5d8;border-top-left-radius:0;border-top-right-radius:0}

.expression-click-parenthesis{display:inline-block;cursor:pointer;padding:1px 3px;border-radius:4px;background:#e8efff;color:#234c97;border-bottom:1px dashed #567ebf}.expression-click-parenthesis:hover,.expression-click-parenthesis:focus-visible{background:#d3e2ff;outline:2px solid #567ebf}.expression-whole-term{display:inline-block}

.expression-letter-keys{grid-column:1/-1;display:flex;flex-wrap:wrap;gap:4px;padding-top:5px;border-top:1px solid #d5dfed}.expression-letter-keys button{flex:1;min-width:28px;min-height:32px;background:#e8efff;color:#234c97}

.function-mini-graph{display:block;width:300px;max-width:100%;margin:10px auto;border:1px solid #d5dfed;border-radius:8px}

/* Compact calculator: keep the problem visible beside the working window. */
.compact-expression-dialog{box-sizing:border-box;width:min(640px,calc(100vw - 24px));max-width:640px;min-height:0;height:auto;max-height:calc(100vh - 40px);padding:10px;margin:0;position:fixed;inset:110px 18px auto auto;overflow:auto}
.compact-expression-dialog::backdrop{background:#17253a20}
.compact-expression-dialog .expression-drag-handle{margin:-10px -10px 8px;padding:7px 10px}
.compact-expression-dialog .expression-inline{flex-wrap:wrap;overflow:visible;gap:4px}
.compact-expression-dialog .expression-single-input{flex:1 1 100%;width:100%;min-height:40px;padding:2px 5px}
.compact-expression-dialog .expression-inline button{min-height:30px;padding:5px 8px}
.compact-expression-dialog .expression-inline input{font-size:18px;padding:5px}
.compact-expression-dialog .expression-inline-both input{font-size:14px;width:76px}
.compact-expression-dialog .expression-entry-controls{gap:4px;margin:7px 0;padding:5px}
.compact-expression-dialog .expression-entry-controls button{min-height:28px;padding:3px 8px}
.compact-expression-dialog .expression-number-pad{grid-template-columns:repeat(6,minmax(0,1fr));width:100%;box-sizing:border-box;gap:4px;padding:5px;margin:6px 0}
.compact-expression-dialog .expression-number-pad button{min-height:30px;padding:3px;font-size:15px}
.compact-expression-dialog .expression-letter-keys{grid-column:1/5;padding-top:0;border:0;gap:4px}
.compact-expression-dialog .expression-letter-keys button{min-width:0;min-height:30px}
.compact-expression-dialog .expression-number-pad [data-number-clear]{grid-column:5/7;min-height:30px}
.compact-expression-dialog .expression-manipulations{margin:5px 0;gap:4px}
.compact-expression-dialog .expression-manipulations button{min-height:28px;padding:4px 8px}
.compact-expression-dialog .expression-tool-status{margin:5px 0;font-size:13px}
.compact-expression-dialog #expressionSavedOperand{margin-top:4px;max-width:100%}
@media(max-width:700px){.compact-expression-dialog{inset:auto 8px 8px;width:calc(100vw - 16px);max-height:65vh}.compact-expression-dialog .expression-single-input .expression-line-editor{min-width:140px}.compact-expression-dialog .expression-inline-both{flex-wrap:wrap}}

/* Phone-style keypad, with letters alongside to preserve a compact window. */
.compact-expression-dialog .expression-number-pad{grid-template-columns:repeat(3,48px) minmax(0,1fr);width:100%;gap:4px}
.compact-expression-dialog .expression-number-pad [data-number-key],
.compact-expression-dialog .expression-number-pad [data-number-backspace]{grid-column:auto}
.compact-expression-dialog .expression-number-pad [data-number-key="1"]{grid-area:1/1}
.compact-expression-dialog .expression-number-pad [data-number-key="2"]{grid-area:1/2}
.compact-expression-dialog .expression-number-pad [data-number-key="3"]{grid-area:1/3}
.compact-expression-dialog .expression-number-pad [data-number-key="4"]{grid-area:2/1}
.compact-expression-dialog .expression-number-pad [data-number-key="5"]{grid-area:2/2}
.compact-expression-dialog .expression-number-pad [data-number-key="6"]{grid-area:2/3}
.compact-expression-dialog .expression-number-pad [data-number-key="7"]{grid-area:3/1}
.compact-expression-dialog .expression-number-pad [data-number-key="8"]{grid-area:3/2}
.compact-expression-dialog .expression-number-pad [data-number-key="9"]{grid-area:3/3}
.compact-expression-dialog .expression-number-pad [data-number-key="."]{grid-area:4/1}
.compact-expression-dialog .expression-number-pad [data-number-key="0"]{grid-area:4/2}
.compact-expression-dialog .expression-number-pad [data-number-backspace]{grid-area:4/3}
.compact-expression-dialog .expression-letter-keys{grid-area:1/4/3/5;align-content:start;margin-left:6px;justify-content:flex-start}
.compact-expression-dialog .expression-letter-keys button{flex:0 0 38px}
.compact-expression-dialog .expression-number-pad [data-number-clear]{grid-area:3/4/4/5;justify-self:start;margin-left:6px;padding:3px 12px}

.compact-expression-dialog .expression-window-actions{display:flex;align-items:center;gap:12px}
.compact-expression-dialog .expression-window-actions [data-close-tool]{border:0;background:transparent;color:#35465f;font-size:25px;line-height:1;min-height:26px;width:28px;padding:0;cursor:pointer}
.compact-expression-dialog .expression-window-actions [data-close-tool]:hover{background:#dce5f3;border-radius:4px}
.compact-expression-dialog .expression-keypad-side{grid-area:1/4/5/5;margin-left:6px;min-width:0;display:flex;flex-direction:column;align-items:flex-start;gap:9px}
.compact-expression-dialog .expression-keypad-side .expression-entry-controls{display:flex;flex-wrap:nowrap;gap:4px;background:transparent;border:0;padding:0;margin:0;max-width:100%}
.compact-expression-dialog .expression-keypad-side .expression-entry-controls label,
.compact-expression-dialog .expression-keypad-side [data-insert-number]{display:none}
.compact-expression-dialog .expression-keypad-side [data-insert-operator]{width:32px;min-width:28px;min-height:32px;padding:2px}
.compact-expression-dialog .expression-keypad-side .expression-letter-keys{display:flex;flex-wrap:wrap;margin:0;padding:0;border:0;gap:4px}
.compact-expression-dialog .expression-keypad-side .expression-letter-keys button{flex:0 0 38px;min-height:32px}
.compact-expression-dialog .expression-variable-key{font-family:'Segoe Print','Comic Sans MS',cursive;font-style:italic;font-weight:500;font-size:20px!important}
.compact-expression-dialog .expression-keypad-side [data-number-clear]{margin:0;padding:3px 12px}
@media(max-width:470px){.compact-expression-dialog .expression-number-pad{grid-template-columns:repeat(3,40px) minmax(0,1fr)}.compact-expression-dialog .expression-keypad-side .expression-entry-controls{flex-wrap:wrap}}

.compact-expression-dialog{width:min(800px,calc(100vw - 24px));max-width:800px}
.compact-expression-dialog .expression-inline{flex-wrap:nowrap;gap:4px}
.compact-expression-dialog .expression-single-input{flex:1 1 auto;width:auto;min-width:0;flex-wrap:nowrap}
.compact-expression-dialog .expression-single-input .expression-line-editor{min-width:100px}
.compact-expression-dialog .expression-single-input #expressionInput{min-width:100px}
.compact-expression-dialog .expression-letter-keys button:not(.expression-variable-key){font-family:inherit;font-style:normal;font-size:16px}
@media(max-width:760px){.compact-expression-dialog{width:calc(100vw - 16px)}.compact-expression-dialog .expression-inline{flex-wrap:wrap}.compact-expression-dialog .expression-single-input{flex-basis:100%}}

.compact-expression-dialog .expression-inline-both input{width:122px;min-width:122px}
@media(max-width:470px){.compact-expression-dialog .expression-inline-both input{width:100px;min-width:80px}}

.completed-results .history-before{color:#657186;font-weight:400}
.completed-results .history-after{color:#234fa0;font-weight:700}
.completed-results .history-arrow{color:#8894a6;font-weight:400}

.completed-results .completed-result:has(.history-after){font-size:13px;white-space:nowrap;overflow-x:auto;max-width:100%;min-width:0}
.completed-results .completed-result:has(.history-after)>span{font-size:13px;white-space:nowrap;overflow-wrap:normal;word-break:normal}
.completed-results .history-before,.completed-results .history-after,.completed-results .history-arrow{display:inline!important;font-size:13px;white-space:nowrap;overflow-wrap:normal;word-break:normal}

.math-stacked-fraction{display:inline-flex!important;flex-direction:column;vertical-align:middle;align-items:stretch;text-align:center;line-height:1.05;white-space:nowrap;margin:0 .14em;font-size:.88em}
.math-stacked-fraction>span{display:block!important;padding:.08em .18em;line-height:1.05;white-space:nowrap}
.math-stacked-fraction>span:first-child{border-bottom:1px solid currentColor}
.expression-whole-term:has(.math-stacked-fraction){white-space:nowrap}

.completed-results .history-step-link{cursor:pointer;border-radius:3px}
.completed-results .history-step-link:hover{background:#eaf1ff}
.completed-results .history-step-link:focus-visible{outline:2px solid #4666ac;outline-offset:2px}
.completed-results .history-step-link[aria-current="step"]{background:#eaf1ff;border-left-color:#234fa0}

/* Keep completed equations compact without shrinking their text. */
.reference-lesson .completed-results:has(.history-step-link){margin:6px 0 12px;padding:7px 9px;border-radius:6px}
.reference-lesson .completed-results:has(.history-step-link) h3{margin:0 0 5px;font-size:12px;line-height:1.3}
.reference-lesson .completed-results:has(.history-step-link) ol{gap:2px}
.reference-lesson .completed-results .history-step-link,
.reference-lesson .completed-results .history-step-link:first-child,
.reference-lesson .completed-results .history-step-link:last-child{padding:3px 7px;border-top:0;border-left-width:2px;line-height:1.3;gap:0;min-height:0}
.reference-lesson .completed-results .history-step-link>span{line-height:1.3}

.pythagorean-dialog{width:min(470px,calc(100vw - 24px));max-width:470px}.pythagorean-dialog svg{display:block;width:280px;max-width:100%;margin:4px auto}.pyth-equation{display:flex;align-items:center;gap:7px;white-space:nowrap;font-size:21px;margin:12px 0}.pyth-equation input{width:78px;min-width:0;padding:7px;border:1px solid #b5c6e2;border-radius:5px;font-size:20px}.pyth-equation sup{align-self:flex-start;font-size:15px}.pythagorean-dialog [data-pyth-close]{border:0;background:transparent;font-size:24px;padding:0 5px}

.triangle-proof-summary{padding:7px 9px!important;margin:6px 0 10px!important}.triangle-proof-summary p{font-size:13px;line-height:1.4;margin:3px 0;white-space:nowrap;overflow-x:auto}.triangle-proof-summary h3{font-size:12px;margin-bottom:5px}

.triangle-proof-work>svg{display:block;width:min(100%,360px);height:auto;margin:6px auto}.triangle-proof-work .completed-results{padding:7px 9px;margin:6px 0 10px}.triangle-proof-work .completed-results p{font-size:13px;margin:3px 0;line-height:1.4}

.application-step-heading{font-size:15px;line-height:1.5;margin:7px 0 10px;color:#345597}

.circle-angle-board{position:relative;width:min(100%,480px);margin:8px auto}.circle-angle-board>svg{display:block;width:100%;height:auto}.circle-angle-slot{position:absolute;transform:translate(-50%,-50%);display:flex;align-items:center;gap:2px;background:#fff5de;border-radius:4px;padding:2px;border:1px solid #d59532;z-index:1;font-size:13px}.circle-angle-slot input{width:42px;min-width:0;padding:3px;border:0;border-radius:3px;font-size:15px;text-align:center;background:white;color:#173c7b}.circle-angle-slot input:disabled{background:#edf0f5}

.circle-angle-slot input{cursor:pointer}.circle-angle-slot input:focus{outline:2px solid #4269ad}.circle-angle-keypad{width:210px;padding:9px;margin:7px auto;background:#f2f6ff;border:1px solid #b7c9e5;border-radius:7px}.circle-angle-keypad strong{font-size:13px}.circle-angle-keypad output{display:block;text-align:right;padding:5px 8px;margin:5px 0;background:white;border:1px solid #d4dfed;font-size:20px}.circle-angle-number-buttons{display:grid;grid-template-columns:repeat(3,1fr);gap:4px}.circle-angle-number-buttons button{padding:5px;min-height:34px}.circle-angle-keypad [data-circle-number-done]{width:100%;margin-top:5px;min-height:32px}

.inner-angle-board{position:relative;width:min(100%,400px);margin:6px auto}.inner-angle-board>svg{display:block;width:100%;height:auto}.inner-angle-slot{position:absolute;transform:translate(-50%,-50%);min-width:38px;min-height:30px;padding:3px 5px!important;font-size:14px!important;background:#fff4d9;border:1px solid #ce9a42;border-radius:5px;color:#254e91}.inner-angle-slot:disabled{opacity:1;background:#edf4ff;color:#245493;border-color:#b5c7e2}

.right-bisector-board{position:relative;width:min(100%,440px);margin:8px auto}.right-bisector-board>svg{display:block;width:100%;height:auto}

/* Compact long division keeps two repetitions visible. */
.decimal-tool-dialog .decimal-written-division{font-size:20px;min-width:190px;line-height:1.25}
.decimal-tool-dialog .decimal-division-scroll{max-height:340px;padding:8px 10px;margin:7px 0}
.decimal-tool-dialog .division-quotient-written{min-height:30px;padding:4px 10px}
.decimal-tool-dialog .division-dividend-written{padding:4px 10px 0}
.decimal-tool-dialog .division-work-written.decimal-tool-rows{padding:0 10px}
.decimal-tool-dialog .division-written-line{min-height:25px}
.decimal-tool-dialog .division-brought-down{padding-top:4px}
.decimal-tool-dialog .division-step-note{font:12px/1.35 sans-serif;color:#52627a;margin:2px 0 5px;max-width:430px;white-space:normal}
.decimal-tool-dialog .division-confirmed-repeat{color:#176346;background:#e6f3e9;border-radius:3px}
.decimal-tool-dialog .decimal-tool-summary{font-size:13px;line-height:1.4;margin:7px 0;padding:7px 9px}
.decimal-tool-dialog .expression-board{font-size:18px;padding:7px 10px;margin:7px 0}
@media(max-height:720px){.decimal-tool-dialog .decimal-division-scroll{max-height:280px}}

/* Students enter quotient, product, and remainder on the number pad. */
.decimal-manual-workspace.has-entry{display:grid;grid-template-columns:minmax(0,1fr) 170px;gap:10px;align-items:start}
.decimal-manual-controls{padding:7px;border:1px solid #d5dfed;border-radius:7px;margin:7px 0}
.decimal-entry-task{margin:0 0 5px;font-size:17px;font-weight:650;white-space:nowrap}
.decimal-manual-form{display:grid;gap:5px}.decimal-manual-form label{font-size:13px}
#decimalManualInput{width:100%;min-height:36px;font-size:20px;text-align:right;padding:4px 7px;box-sizing:border-box}
.decimal-manual-form button{min-height:42px;margin:0}
.decimal-manual-keypad{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:4px;margin-top:7px}
.decimal-manual-keypad button{min-height:42px;padding:5px;font-size:18px;margin:0}
.division-current-digit{background:#fff0c6;border-radius:3px;color:#9b580a}
.decimal-manual-workspace.has-entry .division-step-note{max-width:280px}
@media(max-width:560px){.decimal-manual-workspace.has-entry{grid-template-columns:1fr}.decimal-manual-controls{display:grid;grid-template-columns:120px minmax(0,1fr);gap:7px}.decimal-entry-task{grid-column:1/-1}.decimal-manual-keypad{margin-top:0}}

.math-tools-rail [hidden]{display:none!important}
.substitution-tool-dialog{width:min(480px,calc(100vw - 28px));box-sizing:border-box;padding:14px}
.substitution-tool-dialog p{margin:8px 0}
.substitution-source,.substitution-equation{font-size:21px;font-weight:650;overflow-wrap:anywhere}
.substitution-variables,.substitution-values{display:flex;flex-wrap:wrap;gap:6px;margin:8px 0}
.substitution-tool-dialog button{min-width:44px;min-height:44px;margin:0}
.substitution-tool-dialog [aria-pressed="true"]{background:#304f93;color:white;border-color:#304f93}
.substitution-bound,.substitution-status{font-size:14px;line-height:1.5}
.natural-trial-summary{margin:8px 0;padding:6px 10px;border:1px solid #d5dfed;border-radius:6px}
.natural-trial-summary p{margin:4px 0}
.substitution-expression-row{display:flex;align-items:center;gap:4px;overflow-x:auto;padding:5px;border:1px solid #c8d5e7;border-radius:7px;white-space:nowrap}
.substitution-expression-row>span{min-width:130px;font-size:18px;font-weight:650}
.substitution-expression-row input{width:88px;min-width:75px;min-height:36px}
.substitution-expression-row button{min-height:36px;padding:4px 7px}
.substitution-keypad{display:grid;grid-template-columns:repeat(10,minmax(30px,1fr));gap:4px;margin:8px 0;padding:6px;background:#f2f5fa;border-radius:7px}
.substitution-keypad button{min-height:36px;padding:3px;margin:0}
@media(max-width:520px){.substitution-keypad{grid-template-columns:repeat(5,minmax(34px,1fr))}.substitution-expression-row{flex-wrap:wrap}.substitution-expression-row>span{flex-basis:100%}}