:root{font-family:Inter,ui-sans-serif,system-ui,-apple-system,"Segoe UI",sans-serif;color:#213451;background:#f4f7fd;font-synthesis:none}*{box-sizing:border-box}body{margin:0}button,select,input{font:inherit}button{cursor:pointer}button:disabled{opacity:.45;cursor:not-allowed}[hidden]{display:none!important}.shell{max-width:1560px;margin:auto;padding:0 30px}.topbar{height:86px;display:flex;align-items:center;justify-content:space-between;gap:22px}.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:inherit;min-width:220px}.mark{width:43px;height:43px;border-radius:14px;background:linear-gradient(145deg,#5c7df5,#5b3dc5);display:grid;place-items:center;color:white;font-size:29px;box-shadow:0 7px 20px #6368d02f}.brand strong{font-size:20px;letter-spacing:-.6px;display:block}.brand em{color:#6356d9;font-style:normal}.brand 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8px}.select{border:1px solid #e1e6ee;border-radius:10px;width:100%;background:#f9fbff;color:#2e405a;padding:12px;font-size:13px;outline:none}.select:focus{border-color:#7866e8;box-shadow:0 0 0 3px #7a6ceb20}.tinyhead{display:flex;align-items:center;justify-content:space-between;font-size:12px;font-weight:800;margin:23px 0 6px}.pill{color:#7669db;background:#f2efff;padding:5px 7px;border-radius:6px;font-size:9px;font-weight:700}.coefficient{padding:12px 0;border-bottom:1px solid #eff2f7}.coef-top{display:flex;align-items:center;justify-content:space-between;gap:14px;margin-bottom:10px}.coef-label{font-size:13px;font-weight:800;color:#445170}.coef-input{width:77px;border:1px solid #e1e6ef;border-radius:8px;text-align:right;padding:6px 8px;color:#5549c8;font-weight:750;font-size:13px;background:#fafbff}.coef-slider{width:100%;accent-color:#7263dd;cursor:pointer;height:5px}.sidebar-buttons{display:grid;grid-template-columns:1fr 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0;font-weight:750;letter-spacing:-.6px;overflow-wrap:anywhere}.microtitle{font-size:10px;letter-spacing:1.5px;color:#8894ac;font-weight:800}.graph-actions{display:flex;gap:6px}.canvas-wrap{padding:0 20px;position:relative}#plot{background:linear-gradient(180deg,#fff,#fcfdff);width:100%;height:auto;aspect-ratio:900/480;border:1px solid #edf0f6;border-radius:12px;touch-action:pan-y;display:block}.graph-hint{position:absolute;right:30px;bottom:12px;background:#ffffffd9;backdrop-filter:blur(6px);border:1px solid #f0f2f7;color:#a3aec0;font-size:10px;border-radius:6px;padding:5px 7px;pointer-events:none}.graph-footer{display:flex;justify-content:space-between;padding:14px 24px 17px;font-size:11px;color:#98a2b3}.legend{display:flex;align-items:center;gap:7px}.legend i{display:block;width:24px;height:3px;background:#6855ed;border-radius:5px}.analysis-panel{padding:23px}.analysis-panel .section-heading{margin-bottom:17px}.push-right{margin-left:auto}.stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:10px}.stat{background:#f8f9ff;border:1px solid #eef0fa;border-radius:11px;padding:13px;min-height:78px}.stat span{display:block;color:#95a0b1;font-weight:700;font-size:10px;margin-bottom:8px}.stat strong{display:block;color:#354469;font-size:12px;line-height:1.5;overflow-wrap:anywhere}.subheading{font-size:13px;font-weight:850;margin:23px 0 13px}.variation-scroll{overflow:auto;max-width:100%}.variation{border-collapse:separate;border-spacing:0;width:100%;text-align:center;font-size:12px;border:1px solid #e4e8f4;border-radius:9px;overflow:hidden}.variation td,.variation th{padding:11px 10px;border-right:1px solid #edf0f7;border-bottom:1px solid #edf0f7;white-space:nowrap;min-width:58px}.variation tr:last-child td,.variation tr:last-child th{border-bottom:0}.variation tr>*:last-child{border-right:0}.variation th{color:#6252c9;background:#f6f4ff;min-width:68px}.variation td{color:#435575}.variation .arrow{font-size:24px;color:#6e5add;font-weight:850}.variation .break{color:#de6384;background:#fff5f7}.details{margin-top:17px;display:grid;grid-template-columns:1fr 1fr;gap:9px}.detail{border:1px solid #eef0f7;background:#fdfdff;border-radius:9px;padding:12px;color:#69748b;font-size:12px;line-height:1.65}.detail strong{color:#3f4b66}.hidden-solution{padding:28px;text-align:center;border-radius:12px;background:#f6f4ff;color:#7061bc;font-size:14px}.row-actions{display:flex;gap:9px;flex-wrap:wrap;margin-bottom:15px}.compare-list{display:flex;flex-wrap:wrap;gap:8px}.compare-chip{display:flex;align-items:center;gap:9px;border:1px solid #e8ebf3;padding:10px 13px;border-radius:10px;font-size:12px;line-height:1.4;background:#fafbff}.dot{width:9px;height:9px;border-radius:50%;flex:none}.compare-chip button{border:0;background:none;color:#9ba5b5;font-size:18px;padding:0 4px}.main #comparison{padding:19px 22px}.main #comparison .section-heading{margin-bottom:14px}.view{padding:30px;min-height:430px}.view-heading{display:flex;justify-content:space-between;gap:20px;margin-bottom:26px}.view-heading h2{font-size:27px;margin:7px 0;letter-spacing:-.6px}.view-heading p{color:#8d99ac;margin:0;font-size:13px}.score{background:#f2f0ff;padding:13px 20px;border-radius:12px;text-align:center;align-self:center}.score strong{display:block;font-size:23px;color:#6155cf}.score small{font-size:10px;color:#978bce}.question-title{font-size:18px;color:#40506a;margin:25px 0}.question-options{display:grid;grid-template-columns:1fr 1fr;gap:13px}.answer{border:2px solid #ebedf4;border-radius:13px;background:#fff;padding:12px;text-align:left;color:#495873}.answer:hover:not(:disabled){border-color:#a19aea;background:#faf9ff}.answer.correct{border-color:#4eb788;background:#effbf5}.answer.wrong{border-color:#e88084;background:#fff4f4}.answer b{color:#7566db;margin-right:8px}.answer svg{width:100%;height:auto;background:#fafbff;border-radius:8px;display:block;margin-top:8px}.feedback{margin:15px 0;padding:16px;border-radius:12px;background:#f3f9ff;color:#526782;line-height:1.7;font-size:13px}.solo-chart{max-width:500px;margin:5px auto 18px}.solo-chart svg{width:100%;background:#fafbff;border-radius:12px}.gallery{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.gallery-card{border:1px solid #e5e9f4;background:#fff;border-radius:12px;padding:14px;text-align:left;cursor:pointer}.gallery-card:hover{border-color:#9c90ec;transform:translateY(-2px)}.gallery-card svg{width:100%;display:block;background:#f9fbff;border-radius:9px}.gallery-card strong{display:block;color:#354764;font-size:13px;margin-top:10px}.gallery-card span{color:#9aa3b2;font-size:11px;display:block;margin-top:5px;overflow-wrap:anywhere}.notice{position:fixed;bottom:22px;right:20px;max-width:400px;padding:11px 17px;border-radius:11px;background:#35466f;color:white;box-shadow:0 10px 30px #19295445;font-size:13px;z-index:20;pointer-events:none;opacity:0;transition:opacity .2s}.notice.show{opacity:1}footer{display:flex;justify-content:space-between;gap:12px;padding:27px 0;color:#9aa6b7;font-size:11px}.dark{background:#101727;color:#e7eafa}.dark .panel,.dark .iconbutton,.dark .ghost,.dark .answer,.dark .gallery-card{background:#1a2335;border-color:#2b3852;color:#e3e9f9}.dark .sidebar,.dark .graph-head h2,.dark .stat strong,.dark .detail strong,.dark .section-heading h2{color:#eef1ff}.dark .select,.dark .coef-input,.dark .detail,.dark .stat,.dark .compare-chip{background:#222c41;color:#dae1f2;border-color:#34415a}.dark #plot,.dark .answer svg{background:#131c30}.dark .tip{background:#292342;border-color:#494066}.dark .graph-hint{background:#222b3bd9}.dark .variation th{background:#292840}.dark .variation td{color:#ced8ea}.dark .nav{color:#b6bfd4}.dark .nav.active{color:#d2c8ff;background:#30284f}@media(max-width:1060px){.shell{padding:0 17px}.topbar{flex-wrap:wrap;height:auto;padding:16px 0}.topnav{order:3;width:100%;overflow:auto}.workspace{grid-template-columns:265px minmax(0,1fr)}.sidebar{padding:18px 14px}.welcome{padding:21px 25px}.welcome h1{font-size:24px}.gallery{grid-template-columns:repeat(2,1fr)}}@media(max-width:760px){.shell{padding:0 11px}.topbar{gap:9px}.brand{min-width:0}.brand strong{font-size:18px}.topnav{gap:4px}.nav{font-size:12px;padding:9px 11px}.welcome{border-radius:15px;padding:22px 18px;margin:4px 0 14px;min-height:140px}.welcome h1{font-size:23px}.welcome p{line-height:1.6}.welcome-art{display:none}.workspace{grid-template-columns:1fr;gap:12px}.sidebar{position:static;order:2}.main{order:1;gap:12px}.graph-head{padding:17px 14px 12px;align-items:flex-start}.graph-head h2{font-size:17px}.graph-actions{gap:3px}.graph-actions button{min-width:29px;width:29px;height:30px;padding:0;font-size:17px}.canvas-wrap{padding:0 9px}.graph-hint{right:14px;bottom:5px;font-size:9px}.graph-footer{padding:12px 14px}.analysis-panel{padding:15px}.stats{grid-template-columns:repeat(2,1fr)}.details{grid-template-columns:1fr}.section-heading h2{font-size:14px}.section-heading small{font-size:10px}.view{padding:17px}.gallery{grid-template-columns:repeat(2,1fr);gap:9px}.gallery-card{padding:9px}.view-heading h2{font-size:22px}.question-options{gap:8px}.answer{padding:8px;font-size:12px}.score{padding:9px}.score strong{font-size:19px}footer{flex-direction:column;text-align:center;padding:20px}.sidebar-buttons{grid-template-columns:1fr 1fr}}@media(max-width:390px){.gallery{grid-template-columns:1fr}.graph-head h2{font-size:15px}.question-options{grid-template-columns:1fr}}

/* Lesson, presentation and progressive disclosure tools */
.lesson-tools{margin-top:20px;border-top:1px solid #edf0f6;padding-top:13px}
.lesson-tools .sidebar-buttons{margin-top:8px}
.lesson-tools .sidebar-buttons button{padding:10px 4px}
.saved-panel{margin-top:10px;padding:12px;border:1px solid #e8eaf6;background:#f8faff;border-radius:12px}
.saved-panel .field-label{margin-top:2px}
.saved-panel small{display:block;color:#9aa5b8;line-height:1.5;font-size:10px;margin-top:11px}
.saved-entry{display:flex;align-items:center;justify-content:space-between;gap:5px;padding:8px 2px;border-bottom:1px solid #e4e8f1}
.saved-entry button{font-size:11px;border:0;background:none;color:#6355dd;white-space:nowrap;padding:7px 3px}
.saved-entry .lesson-title{min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;flex:1;font-size:11px;font-weight:750}
.teacher-toolbar{padding:15px 19px;display:flex;align-items:center;justify-content:space-between;gap:18px;background:linear-gradient(112deg,#f9f7ff,#fff)}
.teacher-toolbar strong{display:block;color:#5143b1;font-size:13px;margin-bottom:5px}
.teacher-toolbar small{color:#857cb3;font-size:11px}
.teacher-toolbar .row-actions{margin:0;align-items:center}
.teacher-toolbar .row-actions button{white-space:nowrap}
.difficulty{display:inline-flex;align-items:center;gap:8px;font-size:12px;color:#6b7690;font-weight:700}
.difficulty .select{width:auto;padding:9px}
.variation .break{font-weight:800}
.variation .pole-limits{font-size:13px;font-weight:800;color:#d24878}
.variation .hole-value{color:#a97838}
button:focus-visible,select:focus-visible,input:focus-visible{outline:3px solid #a397f1;outline-offset:2px}
.dark .teacher-toolbar{background:linear-gradient(110deg,#22243b,#1a2335)}
.dark .teacher-toolbar strong{color:#cbbcff}
.dark .saved-panel{background:#1d283c;border-color:#34415a}
.dark .saved-entry{border-color:#34415a}
@media(max-width:920px){.teacher-toolbar{flex-wrap:wrap}.teacher-toolbar .row-actions{width:100%}}
@media(max-width:760px){.teacher-toolbar{padding:13px}.teacher-toolbar .row-actions{flex-wrap:wrap}.teacher-toolbar .row-actions button{flex:1}.difficulty{flex:1}}

/* Direct algebraic function entry */
.formula-entry{display:flex;gap:6px;align-items:stretch}
.formula-entry .select{min-width:0;flex:1;width:1px;font-weight:700;font-size:12px;letter-spacing:-.2px}
.formula-entry button{flex:none;padding:10px 13px;min-width:54px}
.input-hint{display:block;font-size:10px;color:#919caf;line-height:1.6;margin-top:7px}
.formula-entry [aria-invalid="true"]{border:2px solid #dc5c75;background:#fff7f8}
.dark .formula-entry [aria-invalid="true"]{border-color:#fa7b9c}

/* Official VnDoc mascot: optimized from the original asset during CI */
.mark{overflow:hidden}
.brand-mascot{width:39px;height:39px;object-fit:contain;display:block}
.welcome-art{overflow:visible}
.hero-mascot{position:absolute;width:136px;height:136px;object-fit:contain;left:-110px;bottom:-40px;filter:drop-shadow(0 10px 9px #271b8b30)}
@media(max-width:1020px){.hero-mascot{width:104px;height:104px;left:-60px;bottom:-32px}}


/* Visible mathematical annotations and export controls. */
.graph-panel{position:relative;overflow:visible}
.graph-tools{display:flex;gap:8px 18px;align-items:center;flex-wrap:wrap;padding:5px 24px 14px;color:#52607c;font-size:11px;font-weight:750}
.graph-tools label{display:inline-flex;gap:6px;align-items:center;cursor:pointer;white-space:nowrap}
.graph-tools input{accent-color:#6554d9;width:14px;height:14px;margin:0}
.export-menu{position:absolute;z-index:8;right:18px;top:73px;width:min(330px,calc(100% - 36px));padding:16px;background:#fff;border:1px solid #dddff2;border-radius:14px;box-shadow:0 15px 45px #17204c3b}
.export-menu strong{font-size:14px;display:block;margin-bottom:10px}
.export-menu label,.export-menu small{display:block;color:#7e899d;font-size:11px;margin:8px 0}
.export-options{display:grid;grid-template-columns:1fr 1fr;gap:7px;margin-top:12px}
.export-options button{border:1px solid #e4e5f2;background:#f8f9ff;color:#493d9b;padding:9px 8px;border-radius:8px;text-align:left;font-size:11px;font-weight:800;min-height:46px}
.export-options button:hover{background:#eee9ff;border-color:#b8aaf6}
.export-menu small{line-height:1.6}
.graph-point{pointer-events:visiblePainted}
.graph-point circle{filter:drop-shadow(0 2px 3px #00000020)}
.point-label-text{paint-order:stroke}
.graph-cursor{position:absolute;z-index:4;background:#222944ee;color:white;border-radius:9px;padding:8px 11px;pointer-events:none;white-space:nowrap;font-size:12px;font-weight:750;box-shadow:0 8px 20px #22294425}
.worked-solution{margin-top:22px;border-top:1px solid #e9edf8;padding-top:20px}
.worked-heading{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:12px}
.worked-heading strong{font-size:16px;color:#3a4969}
.worked-heading small{display:block;color:#8b98aa;font-size:11px;margin-top:5px}
.math-step{border:1px solid #e8ebf4;border-radius:12px;background:#fcfdff;margin-bottom:10px;overflow:hidden}
.math-step summary{padding:14px 15px;font-size:13px;font-weight:800;color:#435471;cursor:pointer;display:flex;gap:9px;align-items:center;list-style:none}
.math-step summary::-webkit-details-marker{display:none}
.math-step summary::after{content:"⌄";margin-left:auto;color:#7668cd;font-size:20px}
.math-step[open] summary::after{transform:rotate(180deg)}
.math-step[open] summary{background:#f4f2ff;color:#5144ab}
.math-step-number{display:grid;place-items:center;background:#e3ddff;color:#5d4ccc;border-radius:7px;width:26px;height:26px;flex:none;font-weight:900}
.math-step ol{padding:15px 25px 16px 43px;margin:0;display:grid;gap:11px}
.math-line{font-size:12.5px;line-height:1.8;color:#43516b;overflow-wrap:anywhere}
.dark .export-menu{background:#1a2335;border-color:#33405b;color:#e7eafa}
.dark .export-options button{background:#25314a;border-color:#3f4768;color:#d5c9ff}
.dark .math-step{background:#1b263a;border-color:#34415a}
.dark .math-step[open] summary{background:#302848;color:#ddd3ff}
.dark .math-step summary,.dark .math-line,.dark .worked-heading strong{color:#e0e8f7}
.dark .graph-tools{color:#c0c8da}
@media(max-width:760px){.graph-tools{padding:4px 12px 12px;gap:10px;font-size:10px}.export-menu{top:75px;right:9px}.worked-heading{align-items:flex-start;flex-wrap:wrap}.math-step summary{font-size:12px}.math-step ol{padding:10px 16px 15px 32px}.math-line{font-size:12px}.graph-cursor{font-size:10px}}


/* Comparison workspace: clearly distinguish the changing function from references. */
.compare-instruction{color:#69748e;background:#f5f3ff;border:1px solid #e7e2ff;border-radius:10px;padding:12px 14px;font-size:12px;line-height:1.7;margin:2px 0 14px}
.compare-counter{color:#7764cd;font-size:11px;font-weight:750;margin:8px 0 13px}
.compare-chip{max-width:100%;flex-wrap:wrap}
.compare-chip.live-compare{background:#f4efff;border:1px solid #bfb2ee;font-size:12px}
.compare-chip.live-compare strong{font-weight:900}
.compare-list{padding-top:2px}
.dark .compare-instruction{background:#292340;border-color:#46405f;color:#d1c8eb}
.dark .compare-chip.live-compare{background:#302945;border-color:#6d5d9a}


/* Multimodal math input – paste text, LaTeX, a screenshot, drop or select an image */
.formula-dropzone{padding:10px;border:1px dashed #c9c5ef;border-radius:12px;background:#faf9ff}
.formula-dropzone.dragging{border-color:#6551d9;background:#ede7ff;box-shadow:0 0 0 3px #6b55df25}
.formula-dropzone .formula-entry .select{background:#fff}
.formula-input-actions{display:grid;grid-template-columns:1fr 1fr;gap:6px;margin-top:9px}
.formula-input-actions button{padding:9px 4px;white-space:nowrap}
.formula-image-review{margin-top:10px;border-top:1px solid #e2dcf4;padding-top:12px}
.formula-image-review img{width:100%;max-height:185px;object-fit:contain;border-radius:8px;border:1px solid #e2e5ef;background:#fff}
.ocr-results{display:grid;gap:7px;margin-top:8px;font-size:11px;line-height:1.6;color:#63708a}
.ocr-results strong{color:#4339a8;font-size:12px}
.ocr-results small{font-size:10px;color:#8a7299}
.ocr-raw{font-family:ui-monospace,monospace;background:#f2effe;white-space:pre-wrap;word-break:break-word;padding:8px;border-radius:8px}
.ocr-results #formula-ocr-status{color:#5147a4;font-weight:700}
.quiz-report{padding:22px;margin-top:18px;background:#f8f9ff;color:#334666}
.quiz-report h3{font-size:20px;margin:0 0 10px;color:#5143ae}
.quiz-report h4{margin:20px 0 11px;color:#33456a;font-size:15px}
.quiz-answer-heading{padding:10px 13px;background:#edebff;border-radius:10px;font-size:13px}
.quiz-reasoning{display:grid;gap:12px;margin:0;padding-left:22px}
.quiz-reasoning li{font-size:13px;line-height:1.8;padding-left:5px}
.option-explanations{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}
.option-explain{padding:13px;border:1px solid #eadbe1;background:#fff8fa;border-radius:12px;overflow-wrap:anywhere}
.option-explain.right{border-color:#bce6cc;background:#f0fff6}
.option-explain strong{display:block;font-size:12px;color:#3c4c61}
.option-explain p{font-size:12px;line-height:1.7;color:#576781;margin:9px 0 0}
.quiz-full-solution{margin:20px 0;border:1px solid #dedff1;border-radius:12px;padding:14px;background:#fff}
.quiz-full-solution summary{font-weight:800;cursor:pointer;color:#5c49bc;font-size:13px}
.quiz-full-solution h5{margin:16px 0 8px;font-size:12px;color:#3e4c72}
.quiz-full-solution ol{font-size:12px;line-height:1.85;display:grid;gap:7px;padding-left:23px}
.dark .formula-dropzone{background:#22253d;border-color:#63587f}
.dark .formula-dropzone .formula-entry .select{background:#1d2538}
.dark .ocr-raw{background:#292344;color:#dae0ed}
.dark .quiz-report{background:#202842;color:#d8dded}
.dark .quiz-report h3,.dark .quiz-report h4,.dark .quiz-report .quiz-answer-heading,.dark .option-explain strong{color:#e0daff}
.dark .quiz-answer-heading{background:#352e55}
.dark .option-explain{background:#33273d;border-color:#633e58}
.dark .option-explain.right{background:#203d31;border-color:#3a7b59}
.dark .option-explain p{color:#d8dcea}
.dark .quiz-full-solution{background:#202940;border-color:#3b4164}
@media(max-width:760px){.option-explanations{grid-template-columns:1fr}.quiz-report{padding:14px}.formula-input-actions button{font-size:11px}}


/* VNDOC MATHLAB | Math-expert mascot UX refresh */
:root{--brand-blue:#2463eb;--brand-sky:#0ea5e9;--brand-gold:#ffcc4f;--brand-indigo:#544ee9}
html{scroll-behavior:smooth}
body{background:radial-gradient(circle at 8% 3%,#e5f1ff 0,transparent 36%),#f7f9ff}
button,.nav,input,select{transition:background-color .16s ease,box-shadow .16s ease,border-color .16s ease,transform .16s ease}
button:active{transform:scale(.975)}
button:focus-visible,.nav:focus-visible,input:focus-visible,select:focus-visible{outline:3px solid #3b82f6;outline-offset:3px}
.topbar{position:sticky;top:0;z-index:25;background:#f7f9fff2;backdrop-filter:blur(16px);padding:8px 12px;border-radius:0 0 16px 16px;border-bottom:1px solid #e4e9fb;box-shadow:0 6px 24px #183e7220}
.brand-mascot{width:49px;height:49px;object-fit:contain}
.mark{width:54px;height:54px;display:grid;place-items:center;border-radius:16px;background:#fff6dc;border:1px solid #ffeca2}
.math-hero{position:relative;display:grid;grid-template-columns:minmax(0,1.05fr) minmax(240px,.8fr);align-items:center;min-height:318px;padding:35px clamp(22px,4vw,70px);overflow:hidden;border:1px solid #e5e9ff;background:linear-gradient(112deg,#ffffff 0%,#f1f8ff 42%,#dcf1ff 75%,#fff3d6 100%);color:#23395b;isolation:isolate;box-shadow:0 20px 55px #1d468217}
.math-hero::before,.math-hero::after{content:"";position:absolute;border-radius:50%;z-index:-1;pointer-events:none}
.math-hero::before{height:420px;width:420px;right:-90px;top:-125px;background:radial-gradient(circle,#ffe49999 0%,#fbd67a20 65%,transparent 70%)}
.math-hero::after{height:230px;width:230px;right:24%;bottom:-155px;background:#a0d4ff4d}
.hero-copy{max-width:675px;position:relative;z-index:2}
.math-hero .eyebrow{color:#315bc2;background:#e6efff;border:1px solid #c7d9ff;border-radius:99px;display:inline-flex;padding:7px 12px;font-weight:850;letter-spacing:.07em}
.math-hero h1{font-size:clamp(27px,3.3vw,49px);line-height:1.12;letter-spacing:-1.7px;max-width:650px;margin:18px 0 13px;color:#233d73;font-weight:900}
.math-hero h1 span{color:#1269ec}
.math-hero p{font-size:clamp(13px,1.1vw,16px);line-height:1.7;color:#557092;max-width:585px}
.hero-cta{display:flex;align-items:center;gap:12px;margin-top:22px;flex-wrap:wrap}
.hero-cta button{font-weight:800;min-height:46px;padding:11px 21px;border-radius:12px}
.hero-cta .primary{background:#2563eb;color:#fff;box-shadow:0 8px 18px #2563eb33}
.hero-cta .ghost{border:1px solid #ccd8f0;color:#34528b;background:#fff}
.hero-points{display:flex;flex-wrap:wrap;gap:9px 16px;margin-top:19px;color:#557399;font-size:11px;font-weight:800}
.math-hero-art{height:292px;display:flex;position:relative;align-items:end;justify-content:center}
.math-hero-art .hero-mascot{position:relative;inset:auto;width:min(100%,320px);height:320px;object-fit:contain;filter:drop-shadow(0 16px 13px #26487722);z-index:2}
.hero-formula{position:absolute;color:#316fc9;font-size:18px;font-weight:900;padding:10px 15px;background:#ffffffc9;border-radius:12px;box-shadow:0 8px 24px #376abc18;transform:rotate(-8deg)}
.formula-one{left:1%;top:13%}.formula-two{right:-1%;bottom:15%;transform:rotate(8deg);color:#e89e08}
.mascot-side-tip{display:flex;align-items:center;gap:10px;background:#fff9e8;border:1px solid #ffe6a1;border-radius:14px;padding:12px;margin-top:16px}
.mascot-side-tip img{width:70px;height:70px;object-fit:contain;flex:none}
.mascot-side-tip strong{color:#7d5411;font-size:12px}
.mascot-side-tip p{font-size:11px;color:#866b34;line-height:1.6;margin:5px 0 0}
.panel{box-shadow:0 10px 34px #334b760c}
.graph-panel{border-color:#dfe8fa}
.graph-actions button{min-width:40px;min-height:40px}
.formula-dropzone{background:#f7fbff;border:1.5px dashed #a9caed}
.formula-input-actions button,.sidebar-buttons button,.nav{min-height:42px}
.dark .topbar{background:#161e31ed;border-color:#3b4262}
.dark .math-hero{background:linear-gradient(115deg,#232c47,#29355a 55%,#503c35);border-color:#445578;color:#ebefff}
.dark .math-hero h1{color:#edf5ff}.dark .math-hero p{color:#c3d3ed}
.dark .math-hero .eyebrow{background:#263e6d;color:#d7e7ff}
.dark .mascot-side-tip{background:#3b3125;border-color:#795d35}.dark .mascot-side-tip strong{color:#ffda88}.dark .mascot-side-tip p{color:#eacba4}
@media(max-width:980px){.math-hero{grid-template-columns:minmax(0,1fr) minmax(200px,.58fr);min-height:270px;padding:25px}.math-hero-art{height:230px}.math-hero-art .hero-mascot{height:260px}.formula-one{top:5%}.formula-two{bottom:2%}}
@media(max-width:760px){.shell{padding:0 13px}.topbar{height:auto;min-height:64px;padding:8px 3px;flex-wrap:wrap;gap:8px;border-radius:0}.topnav{order:3;width:100%;overflow-x:auto;scrollbar-width:none;display:flex;flex-wrap:nowrap;gap:5px}.topnav::-webkit-scrollbar{display:none}.topnav .nav{white-space:nowrap;min-height:43px;padding:9px 12px;flex:none}.brand-mascot{height:40px;width:40px}.mark{width:44px;height:44px}.math-hero{grid-template-columns:minmax(0,1fr) 125px;min-height:235px;padding:19px 14px;gap:0;border-radius:20px;margin-top:12px}.math-hero h1{font-size:clamp(22px,5.8vw,30px);letter-spacing:-.7px;margin:10px 0}.math-hero .eyebrow{font-size:9px;padding:6px 9px}.math-hero p{font-size:11px;line-height:1.55}.hero-points{font-size:9px;gap:6px 8px;margin-top:12px}.hero-cta{gap:7px;margin-top:13px}.hero-cta button{min-height:43px;padding:9px 11px;font-size:11px}.math-hero-art{height:210px;align-self:end}.math-hero-art .hero-mascot{width:165px;height:205px;max-width:none}.hero-formula{display:none}.workspace{scroll-margin-top:125px}.panel{border-radius:17px}.graph-actions{flex-wrap:wrap}.graph-actions button{min-width:42px;min-height:42px}}
@media(max-width:390px){.math-hero{grid-template-columns:1fr 102px}.math-hero h1{font-size:22px}.math-hero-art .hero-mascot{width:130px;height:190px}.hero-points span:last-child{display:none}.math-hero p{font-size:10px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}button,.nav,input,select{transition:none}}


/* Clean miniature graph for mathematical reasoning — fine, high-contrast on any screen. */
.answer svg.math-mini-graph,.solo-chart svg.math-mini-graph{
 overflow:hidden;display:block;shape-rendering:geometricPrecision;
 text-rendering:optimizeLegibility;
}
.math-mini-graph .mini-axis-number{
 font-family:Inter,Arial,sans-serif;
 font-variant-numeric:tabular-nums;
 paint-order:stroke;
 stroke:#fbfcff;
 stroke-width:.55px;
 stroke-linejoin:round;
}
.answer:focus-visible{outline:3px solid #3286e9;outline-offset:3px}
@media(max-width:760px){
 .answer svg.math-mini-graph{margin-top:10px}
 .answer{min-height:155px}
}