/*! tailwindcss v4.2.1 | MIT License | https://tailwindcss.com */
@layer properties{@supports (((-webkit-hyphens:none)) and (not (margin-trim:inline))) or ((-moz-orient:inline) and (not (color:rgb(from red r g b)))){*,:before,:after,::backdrop{--tw-rotate-x:initial;--tw-rotate-y:initial;--tw-rotate-z:initial;--tw-skew-x:initial;--tw-skew-y:initial;--tw-border-style:solid;--tw-shadow:0 0 #0000;--tw-shadow-color:initial;--tw-shadow-alpha:100%;--tw-inset-shadow:0 0 #0000;--tw-inset-shadow-color:initial;--tw-inset-shadow-alpha:100%;--tw-ring-color:initial;--tw-ring-shadow:0 0 #0000;--tw-inset-ring-color:initial;--tw-inset-ring-shadow:0 0 #0000;--tw-ring-inset:initial;--tw-ring-offset-width:0px;--tw-ring-offset-color:#fff;--tw-ring-offset-shadow:0 0 #0000;--tw-blur:initial;--tw-brightness:initial;--tw-contrast:initial;--tw-grayscale:initial;--tw-hue-rotate:initial;--tw-invert:initial;--tw-opacity:initial;--tw-saturate:initial;--tw-sepia:initial;--tw-drop-shadow:initial;--tw-drop-shadow-color:initial;--tw-drop-shadow-alpha:100%;--tw-drop-shadow-size:initial}}}@layer theme{:root,:host{--font-sans:ui-sans-serif, system-ui, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji";--font-mono:ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;--spacing:.25rem;--default-font-family:var(--font-sans);--default-mono-font-family:var(--font-mono)}}@layer base{*,:after,:before,::backdrop{box-sizing:border-box;border:0 solid;margin:0;padding:0}::file-selector-button{box-sizing:border-box;border:0 solid;margin:0;padding:0}html,:host{-webkit-text-size-adjust:100%;tab-size:4;line-height:1.5;font-family:var(--default-font-family,ui-sans-serif, system-ui, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol", "Noto Color Emoji");font-feature-settings:var(--default-font-feature-settings,normal);font-variation-settings:var(--default-font-variation-settings,normal);-webkit-tap-highlight-color:transparent}hr{height:0;color:inherit;border-top-width:1px}abbr:where([title]){-webkit-text-decoration:underline dotted;text-decoration:underline dotted}h1,h2,h3,h4,h5,h6{font-size:inherit;font-weight:inherit}a{color:inherit;-webkit-text-decoration:inherit;-webkit-text-decoration:inherit;-webkit-text-decoration:inherit;-webkit-text-decoration:inherit;text-decoration:inherit}b,strong{font-weight:bolder}code,kbd,samp,pre{font-family:var(--default-mono-font-family,ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace);font-feature-settings:var(--default-mono-font-feature-settings,normal);font-variation-settings:var(--default-mono-font-variation-settings,normal);font-size:1em}small{font-size:80%}sub,sup{vertical-align:baseline;font-size:75%;line-height:0;position:relative}sub{bottom:-.25em}sup{top:-.5em}table{text-indent:0;border-color:inherit;border-collapse:collapse}:-moz-focusring{outline:auto}progress{vertical-align:baseline}summary{display:list-item}ol,ul,menu{list-style:none}img,svg,video,canvas,audio,iframe,embed,object{vertical-align:middle;display:block}img,video{max-width:100%;height:auto}button,input,select,optgroup,textarea{font:inherit;font-feature-settings:inherit;font-variation-settings:inherit;letter-spacing:inherit;color:inherit;opacity:1;background-color:#0000;border-radius:0}::file-selector-button{font:inherit;font-feature-settings:inherit;font-variation-settings:inherit;letter-spacing:inherit;color:inherit;opacity:1;background-color:#0000;border-radius:0}:where(select:is([multiple],[size])) optgroup{font-weight:bolder}:where(select:is([multiple],[size])) optgroup option{padding-inline-start:20px}::file-selector-button{margin-inline-end:4px}::placeholder{opacity:1}@supports (not ((-webkit-appearance:-apple-pay-button))) or (contain-intrinsic-size:1px){::placeholder{color:currentColor}@supports (color:color-mix(in lab, red, red)){::placeholder{color:color-mix(in oklab, currentcolor 50%, transparent)}}}textarea{resize:vertical}::-webkit-search-decoration{-webkit-appearance:none}::-webkit-date-and-time-value{min-height:1lh;text-align:inherit}::-webkit-datetime-edit{display:inline-flex}::-webkit-datetime-edit-fields-wrapper{padding:0}::-webkit-datetime-edit{padding-block:0}::-webkit-datetime-edit-year-field{padding-block:0}::-webkit-datetime-edit-month-field{padding-block:0}::-webkit-datetime-edit-day-field{padding-block:0}::-webkit-datetime-edit-hour-field{padding-block:0}::-webkit-datetime-edit-minute-field{padding-block:0}::-webkit-datetime-edit-second-field{padding-block:0}::-webkit-datetime-edit-millisecond-field{padding-block:0}::-webkit-datetime-edit-meridiem-field{padding-block:0}::-webkit-calendar-picker-indicator{line-height:1}:-moz-ui-invalid{box-shadow:none}button,input:where([type=button],[type=reset],[type=submit]){appearance:button}::file-selector-button{appearance:button}::-webkit-inner-spin-button{height:auto}::-webkit-outer-spin-button{height:auto}[hidden]:where(:not([hidden=until-found])){display:none!important}}@layer components;@layer utilities{.invisible{visibility:hidden}.visible{visibility:visible}.sr-only{clip-path:inset(50%);white-space:nowrap;border-width:0;width:1px;height:1px;margin:-1px;padding:0;position:absolute;overflow:hidden}.absolute{position:absolute}.fixed{position:fixed}.relative{position:relative}.static{position:static}.start{inset-inline-start:var(--spacing)}.end{inset-inline-end:var(--spacing)}.contents{display:contents}.flex{display:flex}.inline{display:inline}.table{display:table}.grow{flex-grow:1}.transform{transform:var(--tw-rotate-x,) var(--tw-rotate-y,) var(--tw-rotate-z,) var(--tw-skew-x,) var(--tw-skew-y,)}.truncate{text-overflow:ellipsis;white-space:nowrap;overflow:hidden}.border{border-style:var(--tw-border-style);border-width:1px}.shadow{--tw-shadow:0 1px 3px 0 var(--tw-shadow-color,#0000001a), 0 1px 2px -1px var(--tw-shadow-color,#0000001a);box-shadow:var(--tw-inset-shadow), var(--tw-inset-ring-shadow), var(--tw-ring-offset-shadow), var(--tw-ring-shadow), var(--tw-shadow)}.blur{--tw-blur:blur(8px);filter:var(--tw-blur,) var(--tw-brightness,) var(--tw-contrast,) var(--tw-grayscale,) var(--tw-hue-rotate,) var(--tw-invert,) var(--tw-saturate,) var(--tw-sepia,) var(--tw-drop-shadow,)}.filter{filter:var(--tw-blur,) var(--tw-brightness,) var(--tw-contrast,) var(--tw-grayscale,) var(--tw-hue-rotate,) var(--tw-invert,) var(--tw-saturate,) var(--tw-sepia,) var(--tw-drop-shadow,)}}:root{--ink:#17363b;--muted:#526a6f;--paper:#fff;--canvas:#eaf2ef;--panel-warm:#faf8f2;--line:#cddedb;--line-strong:#aac9c5;--teal:#087f82;--teal-dark:#075f62;--teal-soft:#e3f4f1;--coral:#e95f4f;--coral-dark:#c9473b;--coral-soft:#fff0ed;--yellow:#f3c84b;--yellow-soft:#fff8dc;--success:#277948;--success-soft:#e8f6ed;--shadow:0 14px 34px #1840441f}*{box-sizing:border-box}html,body{width:100%;height:100%}html{background:var(--canvas)}body{color:var(--ink);background:var(--canvas);margin:0;font-family:Yu Gothic UI,Hiragino Sans,Meiryo,system-ui,sans-serif;overflow:hidden}button,input,select,textarea{font:inherit;letter-spacing:0}button{cursor:pointer}button:disabled,input:disabled,textarea:disabled{cursor:not-allowed;opacity:.58}button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline-offset:2px;outline:3px solid #087f8247}.sr-only{clip:rect(0, 0, 0, 0);white-space:nowrap;border:0;width:1px;height:1px;margin:-1px;padding:0;position:absolute;overflow:hidden}.app-shell{grid-template-columns:300px minmax(0,1fr);gap:12px;width:min(1440px,100%);height:100dvh;margin:0 auto;padding:12px;display:grid}.learning-panel,.chat-panel{border:1px solid var(--line);background:var(--paper);min-width:0;min-height:0;box-shadow:var(--shadow);border-radius:8px}.learning-panel{overscroll-behavior:contain;background:var(--panel-warm);scrollbar-color:var(--line-strong) transparent;flex-direction:column;display:flex;overflow-y:auto}.teacher-portrait{background:#f8eee4;border:1px solid #eadfce;border-radius:8px;flex:none;height:176px;margin:10px 10px 0;overflow:hidden}.teacher-portrait img{object-fit:cover;object-position:36% 24%;width:100%;height:100%;display:block}.brand-copy{border-bottom:1px solid var(--line);padding:16px 18px 18px}.section-kicker{color:var(--teal-dark);margin:0;font-size:.78rem;font-weight:800;line-height:1.35}h1,h2,p{overflow-wrap:anywhere}h1{margin:5px 0 8px;font-size:2.18rem;font-weight:900;line-height:1.1}.brand-copy>p:last-child{color:var(--muted);margin:0;font-size:.92rem;font-weight:650;line-height:1.65}.progress-section,.starter-actions{border-bottom:1px solid var(--line);padding:16px}.section-heading-row{justify-content:space-between;align-items:center;gap:10px;margin-bottom:12px;display:flex}.section-heading-row h2,.starter-actions h2{margin:0;font-size:.9rem;font-weight:900;line-height:1.4}.reset-button{border:1px solid var(--line);min-height:44px;color:var(--muted);background:#fff;border-radius:6px;padding:0 10px;font-size:.76rem;font-weight:800}.reset-button.armed{color:#8e3128;background:var(--coral-soft);border-color:#e9a69e}.stat-grid{grid-template-columns:repeat(3,minmax(0,1fr));gap:7px;display:grid}.stat-grid>div{border:1px solid var(--line);background:#fff;border-radius:6px;align-content:space-between;gap:8px;min-width:0;min-height:72px;padding:10px;display:grid}.stat-grid span{color:var(--muted);font-size:.72rem;font-weight:800}.stat-grid strong{color:var(--teal-dark);white-space:nowrap;font-size:1.12rem;font-weight:900;line-height:1}.starter-actions{border-bottom:0;gap:8px;display:grid}.starter-actions h2{margin-bottom:3px}.starter-actions button{border:1px solid var(--line);min-height:46px;color:var(--ink);text-align:left;background:#fff;border-radius:6px;padding:0 12px;font-weight:800}.chat-panel{grid-template-rows:auto auto minmax(0,1fr) auto auto;display:grid;overflow:hidden}.chat-header{border-bottom:1px solid var(--line);background:#fff;grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:14px;min-height:94px;padding:14px 18px;display:grid}.chat-title-block h2{margin:3px 0 0;font-size:1.68rem;font-weight:900;line-height:1.2}.mobile-brand,.mobile-stats{display:none}.engine-status{justify-items:end;gap:4px;display:grid}.status-pill{min-height:36px;color:var(--teal-dark);background:var(--teal-soft);white-space:nowrap;border:1px solid #9bc9c6;border-radius:999px;align-items:center;padding:0 12px;font-size:.82rem;font-weight:900;display:inline-flex}.engine-note{color:var(--muted);font-size:.68rem;font-weight:750}.engine-status.error .status-pill,.engine-status.missing .status-pill{color:#8b342e;background:#fff1ef;border-color:#d6a49e}.engine-status.ready .status-pill{color:#235b45;background:#edf8f2;border-color:#89b7a0}.study-session-bar{border-bottom:1px solid var(--line);background:#f8fbfa;grid-template-columns:minmax(150px,.8fr) auto auto minmax(220px,1fr);align-items:center;gap:10px;min-height:58px;padding:7px 18px;display:grid}.compact-goal{min-width:0;color:var(--muted);grid-template-columns:auto minmax(64px,1fr);align-items:center;gap:9px;font-size:.76rem;font-weight:850;display:grid}.compact-goal>span{white-space:nowrap}.goal-track{background:#dce9e6;border-radius:999px;height:8px;overflow:hidden}.goal-track>span{border-radius:inherit;background:var(--success);height:100%;transition:width .22s;display:block}.challenge-chip{border:1px solid var(--line);min-height:32px;color:var(--muted);white-space:nowrap;background:#fff;border-radius:999px;justify-content:center;align-items:center;padding:0 10px;font-size:.72rem;font-weight:850;display:inline-flex}.challenge-chip.active{color:#705b18;background:var(--yellow-soft);border-color:#dfcb82}.visual-mode-toggle{border:1px solid var(--line-strong);min-height:44px;color:var(--muted);white-space:nowrap;cursor:pointer;background:#fff;border-radius:6px;justify-content:center;align-items:center;gap:7px;padding:0 10px;font-size:.75rem;font-weight:850;display:inline-flex;position:relative}.visual-mode-toggle input{opacity:0;pointer-events:none;width:1px;height:1px;position:absolute}.visual-mode-toggle:has(input:focus-visible){outline-offset:2px;outline:3px solid #087f8247}.visual-mode-toggle.active{color:var(--teal-dark);background:var(--teal-soft);border-color:#79aaa6}.visual-switch{background:#dce7e5;border:1px solid #92aaa7;border-radius:999px;align-items:center;width:36px;height:20px;padding:2px;transition:background .16s,border-color .16s;display:flex}.visual-switch>span{background:#fff;border-radius:50%;width:14px;height:14px;transition:transform .16s;box-shadow:0 1px 3px #17363b40}.visual-mode-toggle.active .visual-switch{border-color:var(--teal-dark);background:var(--teal)}.visual-mode-toggle.active .visual-switch>span{transform:translate(16px)}.session-actions{justify-content:flex-end;gap:7px;min-width:0;display:flex}.session-actions button{border:1px solid var(--line-strong);min-height:44px;color:var(--teal-dark);white-space:nowrap;background:#fff;border-radius:6px;padding:0 12px;font-size:.78rem;font-weight:850}.messages{overscroll-behavior:contain;scrollbar-color:var(--line-strong) transparent;background:#f7faf9;flex-direction:column;gap:14px;min-height:0;padding:18px;display:flex;overflow-y:auto}.message{grid-template-columns:38px minmax(0,1fr);align-items:start;gap:9px;width:min(820px,100%);display:grid}.message.student{grid-template-columns:minmax(0,1fr) 38px;align-self:flex-end;width:fit-content;max-width:min(680px,92%)}.message.student .avatar{background:var(--coral);grid-area:1/2}.message.student .bubble{color:#fff;border-color:var(--coral-dark);background:var(--coral);grid-area:1/1}.avatar{color:#fff;background:var(--teal);border-radius:50%;place-items:center;width:38px;height:38px;font-size:.73rem;font-weight:900;display:grid;box-shadow:0 5px 12px #18404429}.bubble{border:1px solid var(--line);background:#fff;border-radius:8px;min-width:0;padding:12px 14px}.message-copy{margin:0;font-size:.97rem;font-weight:650;line-height:1.75}.message.has-problem{width:min(900px,100%)}.message.has-problem .bubble{background:0 0;border:0;padding:0}.message.has-problem .message-copy{border:1px solid var(--line);background:#fff;border-radius:8px;margin-bottom:10px;padding:12px 14px}.thinking-message .bubble{width:fit-content;color:var(--muted);font-size:.88rem;font-weight:800;animation:1.1s ease-in-out infinite alternate thinking-pulse}@keyframes thinking-pulse{0%{opacity:.56}to{opacity:1}}.problem-card{border:1px solid var(--line-strong);color:var(--ink);background:#f1faf8;border-radius:8px;gap:13px;padding:15px;display:grid;box-shadow:0 8px 20px #18404414}.problem-card.status-correct{background:var(--success-soft);border-color:#8bc5a0}.problem-card.status-revealed,.problem-card.status-skipped{background:var(--yellow-soft);border-color:#dccd9c}.problem-top{justify-content:space-between;align-items:center;gap:10px;display:flex}.problem-meta{flex-wrap:wrap;align-items:center;gap:6px;display:flex}.problem-meta>span{color:var(--muted);font-size:.76rem;font-weight:850}.problem-meta>.ai-source{color:#17645f}.problem-status{border:1px solid var(--line);background:#fff;border-radius:999px;align-items:center;min-height:28px;padding:0 8px;display:inline-flex}.problem-status.correct{color:var(--success);border-color:#9dceb0}.problem-status.revealed,.problem-status.skipped{color:#705b18;border-color:#dfcb82}.mode-toggle{border:1px solid var(--line);background:#fff;border-radius:8px;flex:none;grid-template-columns:1fr 1fr;padding:3px;display:grid}.mode-toggle button{min-width:58px;min-height:44px;color:var(--muted);background:0 0;border:0;border-radius:6px;padding:0 10px;font-size:.8rem;font-weight:900}.mode-toggle button.active{color:#fff;background:var(--teal)}.problem-text{font-size:1.7rem;font-weight:900;line-height:1.45;display:block}.html-visual{gap:8px;margin:0;display:grid}.html-visual figcaption{color:var(--muted);justify-content:space-between;align-items:center;gap:10px;font-size:.72rem;font-weight:800;display:flex}.html-visual figcaption strong{color:var(--teal-dark)}.html-visual-canvas{scrollbar-color:var(--line-strong) transparent;background:#fff;border:1px solid #b5cbd8;border-radius:6px;min-height:164px;padding:14px;overflow-x:auto}.html-operation-row{grid-template-columns:minmax(132px,1fr) 44px minmax(132px,1fr);align-items:stretch;gap:10px;min-width:360px;display:grid}.html-quantities-row{grid-template-columns:repeat(auto-fit,minmax(132px,1fr));gap:10px;display:grid}.html-quantity{background:#f8fbfa;border:1px dashed #b5c9c6;border-radius:6px;grid-template-rows:auto minmax(76px,1fr);gap:8px;min-width:0;padding:10px;display:grid}.html-quantity-label,.html-subtraction-labels,.html-group-heading{color:var(--muted);justify-content:space-between;align-items:center;gap:10px;font-size:.75rem;font-weight:800;display:flex}.html-quantity-label strong,.html-subtraction-labels strong,.html-group-heading strong{color:var(--ink);font-size:1rem}.html-token-set,.html-subtraction-tokens{flex-wrap:wrap;place-content:center;align-items:center;gap:7px;min-height:76px;display:flex}.html-token{border:1px solid #17363b2e;border-radius:50%;flex:none;width:19px;height:19px;position:relative;box-shadow:inset 0 1px #ffffffb3}.html-token.coral,.html-place-block.coral{background:var(--coral)}.html-token.teal,.html-place-block.teal{background:var(--teal)}.html-token.yellow,.html-place-block.yellow{background:var(--yellow)}.html-token.green,.html-place-block.green{background:#55a66f}.html-zero{width:48px;height:48px;color:var(--muted);border:2px dashed #9bb5b1;border-radius:50%;place-items:center;font-weight:900;display:grid}.html-place-value{justify-content:center;align-items:end;gap:10px;min-height:76px;display:flex}.html-place-column{min-width:30px;color:var(--muted);justify-items:center;gap:3px;font-size:.65rem;font-weight:800;display:grid}.html-place-blocks{flex-direction:column-reverse;justify-content:flex-start;gap:2px;min-height:32px;display:flex}.html-place-block{border:1px solid #17363b29;border-radius:2px;width:26px;height:7px}.html-place-block.empty{background:0 0;border-style:dashed}.html-place-column strong{color:var(--ink);font-size:.78rem}.html-visual-symbol{min-width:36px;min-height:44px;color:var(--teal-dark);align-self:center;place-items:center;font-size:1.75rem;font-weight:900;line-height:1;display:grid}.html-subtraction,.html-subtraction-bar,.html-group-visual{gap:13px;display:grid}.html-subtraction-tokens{background:#f8fbfa;border:1px dashed #b5c9c6;border-radius:6px;justify-content:flex-start;padding:12px}.html-token.removed{opacity:.34}.html-token.removed:after{content:"";background:#8b342e;width:24px;height:2px;position:absolute;top:8px;left:-3px;transform:rotate(-38deg)}.html-bar-track{background:#fff;border:1px solid #91b4b0;border-radius:6px;width:100%;height:38px;display:flex;overflow:hidden}.html-bar-track .remaining{background:var(--teal)}.html-bar-track .removed{background:repeating-linear-gradient(135deg,#f29b91 0 8px,#fff0ed 8px 16px);border-left:3px solid #fff}.html-visual-instruction{color:var(--muted);font-size:.72rem;font-weight:750}.html-repeated-groups{gap:8px;min-width:min-content;display:grid}.html-repeat-group{background:#f4faf8;border:2px solid #9bc5c1;border-radius:6px;flex-wrap:wrap;place-content:center;gap:5px;min-width:72px;min-height:70px;padding:9px;display:flex}.html-fraction-visual{justify-content:center;align-items:center;gap:12px;min-width:300px;display:flex}.html-fraction-item{align-items:center;gap:12px;min-width:0;display:flex}.html-fraction-shape{gap:8px;min-width:130px;display:grid}.html-fraction-shape>strong{color:var(--ink);text-align:center;font-size:1rem}.html-fraction-wholes{gap:6px;display:grid}.html-fraction-bar{background:#fff;border:1px solid #89aaa6;border-radius:5px;gap:2px;min-width:130px;height:54px;padding:3px;display:grid}.html-fraction-bar>span{background:#edf4f2;border:1px solid #bdd0cd;border-radius:2px}.html-fraction-bar>span.filled.tone-0{background:var(--coral);border-color:#c85f52}.html-fraction-bar>span.filled.tone-1{border-color:var(--teal-dark);background:var(--teal)}.html-fraction-ratio{background:#edf4f2;border:1px solid #89aaa6;border-radius:5px;width:160px;height:54px;overflow:hidden}.html-fraction-ratio>span{background:var(--coral);height:100%;display:block}.html-concept-visual{grid-template-columns:repeat(3,62px);place-content:center;align-items:center;gap:10px;min-height:134px;display:grid}.html-concept-visual strong{color:var(--teal-dark);text-align:center;grid-column:1/-1}.concept-shape{border:1px solid #17363b2e;width:56px;height:56px}.concept-shape.coral{background:var(--coral);border-radius:50%}.concept-shape.yellow{background:var(--yellow);border-radius:6px}.concept-shape.teal{background:var(--teal);border-radius:50% 50% 6px 6px}.fraction-diagram{background:#fff;border:1px solid #9abfbc;border-radius:8px;gap:3px;width:100%;min-height:72px;padding:6px;display:grid}.fraction-diagram>span{background:#f7fbfa;border:1px solid #9abfbc;border-radius:4px;min-width:0}.fraction-diagram>span.filled{background:#ef7465;border-color:#c85f52}.choice-lane{grid-template-columns:repeat(3,minmax(0,1fr));gap:9px;display:grid}.choice-lane button{border:1px solid var(--line);min-width:0;min-height:98px;color:var(--ink);background:#fff;border-radius:8px;grid-template-rows:24px 1fr 18px;place-items:center;gap:5px;padding:8px;display:grid;box-shadow:0 5px 12px #18404412}.choice-lane button.tried{background:var(--coral-soft);border-color:#dfa097}.choice-lane button.correct{background:var(--success-soft);border-color:#74b58d}.choice-index{color:#fff;background:var(--teal);border-radius:50%;place-items:center;width:24px;height:24px;font-size:.72rem;font-weight:900;display:grid}.choice-lane button>strong{overflow-wrap:anywhere;max-width:100%;font-size:1.42rem;font-weight:900;line-height:1.2}.fraction-value{vertical-align:middle;place-items:center;min-width:2.2ch;line-height:1;display:inline-grid}.fraction-numerator,.fraction-denominator{text-align:center;min-width:100%;padding:0 .2em;display:block}.fraction-numerator{border-bottom:2px solid;padding-bottom:.12em}.fraction-denominator{padding-top:.12em}.choice-state{color:var(--muted);font-size:.68rem;font-weight:800}.answer-form{grid-template-columns:minmax(0,1fr) 106px;gap:9px;display:grid}.answer-form input,.composer textarea{border:1px solid var(--line-strong);min-width:0;color:var(--ink);background:#fff;border-radius:8px;font-weight:750}.answer-form input{min-height:52px;padding:0 13px;font-size:1.08rem}.answer-form input[aria-invalid=true]{background:snow;border-color:#d97d72}.answer-form button,.composer button{border:1px solid var(--teal-dark);color:#fff;background:var(--teal);border-radius:8px;min-height:52px;font-weight:900}.problem-feedback{border-left:4px solid var(--line-strong);color:var(--muted);background:#fff;margin:0;padding:9px 11px;font-size:.84rem;font-weight:750;line-height:1.55}.problem-feedback.error{border-left-color:var(--coral);color:#7f342c;background:var(--coral-soft)}.problem-feedback.success{border-left-color:var(--success);color:#245c39;background:var(--success-soft)}.scratchpad{color:var(--muted);gap:6px;font-size:.76rem;font-weight:850;display:grid}.scratchpad textarea{resize:vertical;border:1px solid var(--line-strong);width:100%;min-height:78px;color:var(--ink);background:#fff;border-radius:8px;padding:10px;line-height:1.5}.problem-actions{flex-wrap:wrap;gap:8px;display:flex}.problem-actions button{border:1px solid var(--line-strong);min-height:44px;color:var(--ink);background:#fff;border-radius:6px;padding:0 13px;font-weight:850}.problem-actions .next-button{color:#fff;border-color:var(--teal-dark);background:var(--teal)}.prompt-strip{border-top:1px solid var(--line);scrollbar-color:var(--line-strong) transparent;background:#fff;gap:8px;min-width:0;padding:10px 18px;display:flex;overflow-x:auto}.prompt-strip button{border:1px solid var(--line);min-height:44px;color:var(--teal-dark);white-space:nowrap;background:#fff;border-radius:8px;flex:none;padding:0 12px;font-size:.85rem;font-weight:850}.composer{border-top:1px solid var(--line);background:#fff;grid-template-columns:minmax(0,1fr) 84px;align-items:end;gap:9px;padding:10px 18px 14px;display:grid}.composer textarea{resize:vertical;width:100%;min-height:52px;max-height:104px;padding:14px;line-height:1.45;display:block}.tools-backdrop{z-index:40;background:#112c307a;place-items:center;padding:18px;display:grid;position:fixed;inset:0}.tools-dialog{border:1px solid var(--line-strong);background:#fff;border-radius:8px;grid-template-rows:auto minmax(0,1fr);width:min(760px,100%);max-height:min(860px,100dvh - 36px);display:grid;overflow:hidden;box-shadow:0 24px 70px #0a2a2d47}.tools-dialog-header{border-bottom:1px solid var(--line);background:#fff;justify-content:space-between;align-items:center;gap:16px;padding:15px 18px;display:flex}.tools-dialog-header h2{margin:2px 0 0;font-size:1.42rem;line-height:1.2}.tools-dialog-header button,.tool-command-row button,.problem-list-row button{border:1px solid var(--line-strong);min-height:44px;color:var(--ink);background:#fff;border-radius:6px;padding:0 12px;font-weight:850}.tools-dialog-body{overscroll-behavior:contain;scrollbar-color:var(--line-strong) transparent;min-height:0;overflow-y:auto}.tool-section{border-bottom:1px solid var(--line);padding:17px 18px}.tool-section:last-child{border-bottom:0}.tool-section-heading{justify-content:space-between;align-items:center;gap:12px;margin-bottom:12px;display:flex}.tool-section-heading h3{margin:0;font-size:.98rem;line-height:1.35}.tool-section-heading>span{color:var(--muted);font-size:.74rem;font-weight:800}.settings-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;display:grid}.settings-grid label,.settings-grid fieldset{min-width:0;color:var(--muted);border:0;align-content:start;gap:7px;margin:0;padding:0;font-size:.76rem;font-weight:850;display:grid}.settings-grid legend{padding:0}.settings-grid select{border:1px solid var(--line-strong);width:100%;min-height:44px;color:var(--ink);background:#fff;border-radius:6px;padding:0 10px;font-weight:800}.segmented-control{border:1px solid var(--line);background:#f6f9f8;border-radius:8px;grid-template-columns:repeat(4,minmax(0,1fr));padding:3px;display:grid}.segmented-control.two{grid-template-columns:repeat(2,minmax(0,1fr))}.segmented-control.three{grid-template-columns:repeat(3,minmax(0,1fr))}.segmented-control button{min-width:0;min-height:44px;color:var(--muted);background:0 0;border:0;border-radius:6px;font-size:.8rem;font-weight:900}.segmented-control button.active{color:#fff;background:var(--teal)}.goal-row{color:var(--muted);grid-template-columns:auto minmax(80px,1fr);align-items:center;gap:10px;margin-top:13px;font-size:.76rem;font-weight:850;display:grid}.tool-command-row{grid-template-columns:repeat(4,minmax(0,1fr));gap:8px;margin-top:13px;display:grid}.tool-command-row button{min-width:0;padding:6px 9px;font-size:.78rem;line-height:1.3}.tool-command-row .primary-command{color:#fff;border-color:var(--teal-dark);background:var(--teal)}.topic-stat-list{border-top:1px solid var(--line);border-bottom:1px solid var(--line);gap:1px;display:grid}.topic-stat-list>div{border-bottom:1px solid var(--line);grid-template-columns:minmax(0,1fr) 82px 72px;align-items:center;gap:10px;min-height:42px;font-size:.78rem;display:grid}.topic-stat-list>div:last-child{border-bottom:0}.topic-stat-list span{color:var(--muted);text-align:right;font-weight:750}.problem-list{border-top:1px solid var(--line);display:grid}.problem-list-row{border-bottom:1px solid var(--line);grid-template-columns:minmax(0,1fr) auto;align-items:center;gap:10px;min-height:58px;padding:7px 0;display:grid}.problem-list-row>span{min-width:0;font-size:.82rem;font-weight:750;line-height:1.5}.problem-list-row>div{gap:6px;display:flex}.problem-list-row button{min-height:40px;padding:0 9px;font-size:.74rem}.empty-list{color:var(--muted);margin:0;padding:15px 0;font-size:.8rem}button{transition:transform .14s,border-color .14s,background-color .14s,box-shadow .14s}@media (hover:hover){button:not(:disabled):hover{border-color:var(--teal);transform:translateY(-1px);box-shadow:0 5px 12px #1840441c}}button:not(:disabled):active{transform:translateY(0)}@media (width<=960px){.app-shell{grid-template-columns:260px minmax(0,1fr)}.teacher-portrait{height:190px}h1{font-size:1.82rem}.stat-grid{grid-template-columns:1fr}.stat-grid>div{grid-template-columns:1fr auto;align-items:center;min-height:48px}.study-session-bar{grid-template-columns:minmax(140px,1fr) auto minmax(210px,auto)}.challenge-chip{display:none}}@media (width<=760px){body{overflow:hidden}.app-shell{width:100%;height:100dvh;padding:0;display:block}.learning-panel{display:none}.chat-panel{width:100%;height:100dvh;box-shadow:none;border:0;border-radius:0}.chat-header{min-height:0;padding:calc(9px + env(safe-area-inset-top)) 12px 9px;grid-template-columns:minmax(0,1fr) auto;gap:8px 12px}.mobile-brand{color:var(--ink);align-items:center;gap:8px;margin-bottom:4px;font-size:.79rem;font-weight:900;display:flex}.mobile-brand img{object-fit:cover;object-position:36% 22%;border:1px solid #e7d6c8;border-radius:50%;width:32px;height:32px}.chat-title-block .section-kicker{display:none}.chat-title-block h2{margin:0;font-size:1.28rem}.status-pill{min-height:34px;padding:0 10px;font-size:.72rem}.engine-note{display:none}.mobile-stats{grid-column:1/-1;grid-template-columns:repeat(3,minmax(0,1fr));gap:6px;display:grid}.mobile-stats>span{border:1px solid var(--line);min-width:0;color:var(--muted);white-space:nowrap;background:#f8fbfa;border-radius:6px;padding:6px 8px;font-size:.67rem;font-weight:750}.mobile-stats strong{color:var(--teal-dark);font-size:.83rem}.mobile-reset{border:1px solid var(--line);min-height:44px;color:var(--muted);background:#fff;border-radius:6px;grid-column:1/-1;font-size:.7rem;font-weight:800}.mobile-reset.armed{color:#8e3128;background:var(--coral-soft);border-color:#e9a69e}.study-session-bar{grid-template-columns:minmax(112px,1fr) auto auto;gap:6px;min-height:54px;padding:5px 10px}.compact-goal{grid-area:1/1;grid-template-columns:auto minmax(52px,1fr);gap:7px;font-size:.68rem}.challenge-chip{display:none}.challenge-chip.active{grid-area:2/1/auto/-1;justify-self:stretch;min-height:30px;display:inline-flex}.visual-mode-toggle{grid-area:1/2;min-height:44px;padding:0 8px;font-size:.7rem}.session-actions{grid-area:1/3}.session-actions button:first-child{display:none}.session-actions button{min-height:44px;padding:0 10px;font-size:.72rem}.messages{gap:12px;padding:12px 10px}.message,.message.student{grid-template-columns:32px minmax(0,1fr);gap:7px;width:100%;max-width:100%}.message.student{grid-template-columns:minmax(0,1fr) 32px;width:fit-content;max-width:94%}.avatar{width:32px;height:32px;font-size:.64rem}.bubble,.message.has-problem .message-copy{padding:10px 11px}.message-copy{font-size:.9rem;line-height:1.65}.problem-card{gap:11px;padding:11px}.problem-top{align-items:flex-start}.problem-meta{gap:4px}.problem-meta>span{font-size:.68rem}.problem-status{min-height:24px;padding:0 6px}.mode-toggle button{min-width:50px;min-height:44px;padding:0 7px;font-size:.74rem}.problem-text{font-size:1.28rem}.html-visual-canvas{min-height:148px;padding:10px}.html-operation-row{grid-template-columns:minmax(108px,1fr) 32px minmax(108px,1fr);gap:6px;min-width:270px}.html-quantity{padding:8px}.html-token-set,.html-subtraction-tokens{gap:5px}.html-token{width:17px;height:17px}.html-token.removed:after{width:21px;top:7px}.html-visual-symbol{min-width:28px;font-size:1.45rem}.html-repeat-group{min-width:66px;min-height:64px;padding:7px}.html-fraction-visual{min-width:270px}.html-fraction-shape,.html-fraction-bar{min-width:112px}.fraction-diagram{min-height:56px;padding:4px}.choice-lane{gap:6px}.choice-lane button{grid-template-rows:22px 1fr 16px;min-height:88px;padding:6px 3px}.choice-index{width:22px;height:22px;font-size:.66rem}.choice-lane button>strong{font-size:1.12rem}.choice-state{font-size:.6rem}.answer-form{grid-template-columns:minmax(0,1fr) 88px;gap:7px}.answer-form input,.answer-form button{min-height:48px}.problem-actions button{flex:auto;min-height:44px}.scratchpad textarea{resize:none;min-height:72px}.prompt-strip{gap:7px;padding:8px 10px}.prompt-strip button{min-height:44px;padding:0 10px;font-size:.78rem}.composer{padding:8px 10px calc(8px + env(safe-area-inset-bottom));grid-template-columns:minmax(0,1fr) 70px;gap:7px}.composer textarea,.composer button{min-height:48px}.composer textarea{resize:none;padding:12px}.tools-backdrop{place-items:stretch stretch;padding:0}.tools-dialog{border:0;border-radius:0;width:100%;height:100dvh;max-height:none}.tools-dialog-header{padding:calc(12px + env(safe-area-inset-top)) 13px 12px}.tools-dialog-header h2{font-size:1.24rem}.tool-section{padding:14px 12px}.settings-grid{grid-template-columns:1fr;gap:11px}.tool-command-row{grid-template-columns:repeat(2,minmax(0,1fr))}.problem-list-row{grid-template-columns:1fr;gap:6px}.problem-list-row>div{justify-content:flex-end}}@media (width<=360px){.chat-header{padding-left:9px;padding-right:9px}.status-pill{padding:0 8px}.mobile-stats>span{padding:5px;font-size:.62rem}.problem-meta>span:nth-child(2){display:none}.mode-toggle button{min-width:46px}.visual-mode-toggle{gap:0;padding:0 6px}.visual-mode-toggle>span:last-child{display:none}}@media (prefers-reduced-motion:reduce){*,:before,:after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important;animation-iteration-count:1!important}}@media (prefers-contrast:more){:root{--line:#799b97;--line-strong:#507d78}}@property --tw-rotate-x{syntax:"*";inherits:false}@property --tw-rotate-y{syntax:"*";inherits:false}@property --tw-rotate-z{syntax:"*";inherits:false}@property --tw-skew-x{syntax:"*";inherits:false}@property --tw-skew-y{syntax:"*";inherits:false}@property --tw-border-style{syntax:"*";inherits:false;initial-value:solid}@property --tw-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-shadow-color{syntax:"*";inherits:false}@property --tw-shadow-alpha{syntax:"<percentage>";inherits:false;initial-value:100%}@property --tw-inset-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-inset-shadow-color{syntax:"*";inherits:false}@property --tw-inset-shadow-alpha{syntax:"<percentage>";inherits:false;initial-value:100%}@property --tw-ring-color{syntax:"*";inherits:false}@property --tw-ring-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-inset-ring-color{syntax:"*";inherits:false}@property --tw-inset-ring-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-ring-inset{syntax:"*";inherits:false}@property --tw-ring-offset-width{syntax:"<length>";inherits:false;initial-value:0}@property --tw-ring-offset-color{syntax:"*";inherits:false;initial-value:#fff}@property --tw-ring-offset-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-blur{syntax:"*";inherits:false}@property --tw-brightness{syntax:"*";inherits:false}@property --tw-contrast{syntax:"*";inherits:false}@property --tw-grayscale{syntax:"*";inherits:false}@property --tw-hue-rotate{syntax:"*";inherits:false}@property --tw-invert{syntax:"*";inherits:false}@property --tw-opacity{syntax:"*";inherits:false}@property --tw-saturate{syntax:"*";inherits:false}@property --tw-sepia{syntax:"*";inherits:false}@property --tw-drop-shadow{syntax:"*";inherits:false}@property --tw-drop-shadow-color{syntax:"*";inherits:false}@property --tw-drop-shadow-alpha{syntax:"<percentage>";inherits:false;initial-value:100%}@property --tw-drop-shadow-size{syntax:"*";inherits:false}