/* Hanz Math — editorial identity. Shared tokens keep the learning tools coherent. */
:root{--ink:#18382f;--dark:#123b30;--muted:#6c776d;--line:#dedfd4;--paper:#f5f4ec;--cream:#eeeee3;--green:#22583e;--mint:#dbf478;--mint-deep:#d0ec68;--max:1280px;--shadow:0 18px 45px #173a3010}
body{background:#f8f8f2;color:var(--ink)}h1,h2,h3{letter-spacing:-.055em}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}.btn{border-radius:4px;font-weight:600}.btn-dark{background:var(--dark)}.btn-dark:hover{background:#265943}.btn-mint{background:var(--mint)}.eyebrow{font-family:'DM Sans',sans-serif;letter-spacing:.15em;color:#66764b;font-size:10px}.announcement{background:#153e31;color:#e7edcf;height:30px;font-size:10px}.announcement a{color:#e0f58e}.ann-dot{background:#dcf578}.site-header{background:#f8f8f2f5;border-color:#dfe2d6}.header-inner{height:83px}.brand-mark{border-radius:3px;background:#143d30;color:#e4f48b}.brand-dot{color:#ddf471}.brand-name{color:#193b2e;font-size:24px}.brand-name span{color:#6a7958}.nav-link{font-size:12px;color:#566555}.nav-link.active:after{bottom:-32px;background:#305c3b}.header-actions .btn{border-radius:3px;padding:11px 18px}.header-actions .login-link{font-size:12px}.site-footer{background:#12382b;color:#e2e6d7}.site-footer .brand-mark{background:#dcef91;color:#173c2b}.site-footer .brand-dot{color:#173c2b}.site-footer .brand-name span{color:#d4deab}.footer-bottom{border-color:#446044}.footer-main>div:first-child p,.footer-links a{color:#c2ccb5}.footer-links{gap:80px}.section-top h2{font-size:clamp(30px,3vw,43px);font-weight:600}.section-top p{font-size:13px}.text-link{color:#214d35}.serif-italic{font-style:normal}.page-hero{background:#eeefe4}.page-hero h1{font-weight:600}.page-hero:after{color:#d5dbc3}.course-card{border:1px solid #daddcf;border-radius:5px;background:#fcfcf7;box-shadow:none}.course-card:hover{transform:translateY(-6px);border-color:#829575;box-shadow:0 16px 32px #233c3010}.course-card-cover{height:208px}.course-card-cover:after{content:'↗';position:absolute;right:16px;top:16px;width:32px;height:32px;display:grid;place-items:center;background:#e8efbf;color:#173c2c;border-radius:50%;font-size:20px;opacity:0;transform:translate(-4px,4px);transition:.25s}.course-card:hover .course-card-cover:after{opacity:1;transform:none}.course-card-cover .course-art{filter:saturate(.68)}.course-card-body{padding:21px 18px 18px}.course-card-meta{font-size:9px;color:#657448;flex-wrap:wrap;gap:4px}.course-card h3{font-size:19px;font-weight:600;line-height:1.3;margin:16px 0 7px}.course-zh{color:#647253;font-size:13px}.course-card p{font-size:12px}.course-code{border-radius:2px;font-size:9px}.course-demo-badge{background:#e9edda;border-radius:2px}.course-card-foot{flex-wrap:wrap;row-gap:8px}.course-card-foot b{font-size:12px}.course-grid{gap:20px}.stage-choice{border-radius:4px}.stage-choice.active{background:#244b35}.search-box,.search-box input,.select-wrap select,.chip{border-radius:4px}.note-card,.stat-card,.dashboard-block,.purchase-card,.auth-box,.studio-panel,.account-preview,.checkout-panel,.checkout-summary,.article-aside-box{border-radius:5px}.notes-page,.catalog-layout{padding-bottom:90px}.note-card{background:#fcfcf7}.notes-grid{gap:24px}.auth-illustration{background:#153c2d}.auth-display-formula{color:#dbed9b}.auth-illustration-inner>span{color:#d9e5b8}.about-bottom{background:#183f2e}.about-bottom h2{color:#f2f3dd}.about-bottom i{color:#dbf478}.filter-chips{gap:9px}.course-detail-top{background:#eeefe4}.course-detail-top h1{font-weight:500}.purchase-card{background:#fff}.catalog-stage-heading{border-top:1px solid #daddcf;padding-top:25px}.stage-empty{background:#eef0e4;border:1px solid #d5ddc6;border-radius:5px}
/* Opening spread */
.editorial-hero{background:#f3f3e9;overflow:hidden}.hero-kicker{padding:30px 0 23px;display:flex;justify-content:space-between;border-bottom:1px solid #d5dbca;font-size:10px;letter-spacing:.12em;color:#657453}.hero-kicker>span:first-child{display:flex;align-items:center;gap:9px;font-weight:700}.hero-kicker i{height:7px;width:7px;border-radius:50%;background:#345b3c}.hero-kicker>span:last-child{letter-spacing:.06em}.editorial-hero-grid{display:grid;grid-template-columns:1.04fr 1fr;gap:56px;padding:56px 0 47px;align-items:center}.edition-label{font-size:12px;letter-spacing:.1em;margin-bottom:24px;color:#5d6c52}.editorial-copy h1{font-size:clamp(50px,5.05vw,78px);font-weight:600;line-height:1.35;letter-spacing:-.075em;margin:0 0 25px;white-space:nowrap}.title-outline{color:#5e7455}.title-accent{position:relative;z-index:0}.title-accent:after{content:'';position:absolute;left:0;right:0;bottom:5%;height:25%;background:#d7ef82;z-index:-1;transform:rotate(-2deg)}.editorial-copy>p{font-size:14px;line-height:2.1;color:#66735f;margin-bottom:29px}.editorial-actions{display:flex;gap:26px;align-items:center}.editorial-actions .btn{padding:16px 21px;font-size:13px}.editorial-secondary{font-size:12px;border-bottom:1px solid #9eac87;padding:8px 0;display:flex;gap:18px}.hero-footnote{display:flex;align-items:center;gap:14px;margin-top:46px;font-size:11px;color:#5e6d51}.tiny-asterisk{font-size:33px;color:#4f6843;line-height:1}.hero-footnote small{display:block;font-size:8px;letter-spacing:.14em;margin-top:4px}.hero-index{padding:18px 0 23px;border-top:1px solid #d5dbca;display:flex;justify-content:space-between;font-size:9px;letter-spacing:.12em;color:#738061}.hero-index span:nth-child(2){letter-spacing:.2em}
/* Functional, keyboard-accessible derivative study — no autoplay or fake controls. */
.intuition-lab{position:relative;background:#163f31;color:#eaf0d7;border-radius:5px;padding:24px 25px 0;transform:rotate(1.3deg);box-shadow:14px 16px 0 #e0e5cf;min-width:0}.lab-top{display:flex;justify-content:space-between;font-size:8px;letter-spacing:.13em;border-bottom:1px solid #496344;padding-bottom:18px;color:#c3d4a8}.lab-top>span:first-child{display:flex;align-items:center;gap:8px}.lab-top i{width:5px;height:5px;border-radius:50%;background:#d9f47a}.lab-caption{padding-top:28px}.lab-caption h2{font-size:23px;letter-spacing:-.03em;font-weight:500;margin-bottom:5px}.lab-caption>span{font-size:8px;letter-spacing:.15em;color:#b5c794}.lab-plot{padding:7px 0 0}.lab-plot .interactive-box{padding:0;border:0;background:none;margin:0;box-shadow:none;border-radius:0}.lab-plot .interactive-intro{display:flex;justify-content:flex-end;padding-top:12px}.lab-plot .interactive-intro>div:first-child{display:none}.lab-plot .interactive-value{background:#ffffff0b;border:1px solid #6c8252;border-radius:3px;color:#d6e8b1;font-size:12px;padding:8px 12px}.lab-plot .interactive-value strong{color:#e2f68b;font-size:17px;font-weight:500}.lab-plot .graph-svg{height:224px;background:none;overflow:hidden}.lab-plot #curve-path{stroke:#dff782;stroke-width:3}.lab-plot #tangent-line{stroke:#d8bba0;stroke-width:1.5}.lab-plot #graph-dot{fill:#f4edbb;stroke:#173e2c;stroke-width:2}.lab-plot .graph-svg>line{stroke:#496749;stroke-dasharray:3 6}.lab-plot .range-row{color:#d9e6bc;font-size:11px;gap:16px;padding-bottom:24px}.lab-plot input[type=range]{accent-color:#dff782;cursor:ew-resize;min-width:0;flex:1;width:100%}.lab-plot .range-row>span{white-space:nowrap}.lab-bottom{border-top:1px solid #496344;padding:17px 0;display:flex;justify-content:space-between;font-size:10px;letter-spacing:.03em;color:#becda9}.lab-stamp{position:absolute;right:-25px;top:49px;transform:rotate(11deg);background:#dff487;color:#24412c;padding:14px 17px;font:16px/1.05 Georgia,serif;box-shadow:1px 3px 0 #102f2920}.lab-stamp em{font-size:24px}
/* Stage choices */
.path-section{padding:95px 0;background:#fafaf5}.path-layout{display:grid;grid-template-columns:.8fr 1.8fr;gap:85px;align-items:center}.path-intro h2{font-weight:500;font-size:35px;line-height:1.5;margin:20px 0 18px}.path-intro>p{font-size:13px;color:#727b68;line-height:2}.path-intro>.text-link{font-size:12px;margin-top:15px}.path-options{display:grid;grid-template-columns:1fr 1fr;gap:22px}.path-tile{background:#e9eddf;border:1px solid #d9dfcc;border-radius:4px;overflow:hidden;padding:23px 26px 0;transition:transform .25s,box-shadow .25s}.path-tile:hover{transform:translateY(-6px);box-shadow:0 12px 24px #183f3010;color:inherit}.path-tile-top{display:flex;gap:14px;align-items:center;font-size:9px;letter-spacing:.09em}.path-tile-top>span:nth-child(2){flex:1}.path-tile-top>svg{width:19px}.path-illustration{height:145px;display:flex;align-items:center;justify-content:center;position:relative;font:italic 103px/1 Georgia,serif;color:#4a6844}.path-illustration:after{content:'';position:absolute;inset:20px 35px;border:1px solid #82956b50;border-radius:50%;transform:rotate(-30deg)}.path-illustration sup{font-size:45px;align-self:flex-start;margin-top:20px}.path-equals{font-size:48px;margin-left:7px}.path-math{font-size:22px;line-height:3.4;margin-left:3px}.path-tile-university{background:#e9e8db;border-color:#d8d9c7}.path-tile-university .path-illustration{color:#52604a}.path-tile-university .path-illustration:after{border-radius:0;inset:26px 48px;transform:rotate(-30deg) skew(12deg)}.path-tile-copy h3{font-size:27px;font-weight:500;margin:8px 0 10px}.path-tile-copy p{font-size:11px;color:#67735e;line-height:1.9;min-height:42px}.path-tile-foot{border-top:1px solid #cbd3bb;display:flex;justify-content:space-between;padding:18px 0;font-size:11px;margin-top:20px}.path-tile-foot>span:last-child{font-size:21px;line-height:1}
.editorial-courses{background:#f2f3e9;border-top:1px solid #e1e4d6;padding:83px 0}.collection-note{display:flex;align-items:center;justify-content:space-between;border-top:1px solid #d5dbca;margin-top:29px;padding-top:20px;gap:20px}.collection-note>span{font-size:12px;white-space:nowrap}.collection-note>p{font-size:11px;color:#758062;margin:0}.editorial-method{background:#183f30;color:#edf0dd;padding:93px 0 86px}.method-title{position:relative}.method-title>.eyebrow{color:#c6d6a2}.method-title h2{font-size:clamp(32px,3.8vw,54px);font-weight:400;line-height:1.55;margin:23px 0}.method-title h2>span{color:#d4ed82}.method-title>p{position:absolute;right:0;bottom:7px;font-size:12px;line-height:2;color:#c2cfac}.method-panels{display:grid;grid-template-columns:repeat(3,1fr);gap:44px;margin-top:55px}.method-panel{border-top:1px solid #6c7e56;padding-top:19px}.method-panel>div{display:flex;justify-content:space-between;align-items:center;color:#b5ca8d;font-size:9px;letter-spacing:.12em}.method-panel b{font:45px/1 Georgia,serif;color:#d9ed9e;font-weight:400}.method-panel h3{font-size:21px;font-weight:400;letter-spacing:-.02em;margin:25px 0 12px}.method-panel p{color:#bac9a6;font-size:12px;line-height:2;margin:0;max-width:320px}
.editorial-notes{padding:110px 0;background:#f9f9f2}.editorial-notes-grid{display:grid;grid-template-columns:1fr 1fr;gap:115px;align-items:center}.note-preview{padding:25px 32px 0;background:#f0f0e2;border:1px solid #d9ddc8;box-shadow:12px 14px 0 #e6e9d8;transform:rotate(-2deg)}.note-preview-bar{display:flex;justify-content:space-between;font-size:9px;letter-spacing:.1em;border-bottom:1px solid #cbd2b8;padding-bottom:16px}.note-margin{display:block;font-size:8px;letter-spacing:.12em;margin-top:26px;color:#7c8868}.note-preview h3{font-weight:400;font-size:35px;margin:15px 0 21px;line-height:1.4}.note-equation{font:italic 23px Georgia,serif;padding-bottom:22px;border-bottom:1px solid #cbd2b8}.note-figure{height:150px;overflow:hidden;mix-blend-mode:multiply;opacity:.9;margin:18px 0}.note-figure .course-art{height:100%;filter:saturate(.5)}.note-preview-footer{display:flex;justify-content:space-between;font-size:8px;padding:16px 0;border-top:1px solid #cbd2b8}.editorial-notes-copy h2{font-size:clamp(34px,3.4vw,49px);font-weight:500;line-height:1.5;margin:25px 0}.editorial-notes-copy h2 span{color:#768357}.editorial-notes-copy p{font-size:13px;line-height:2.1;color:#737c65;max-width:400px;margin-bottom:30px}.notes-micro{font-size:8px;letter-spacing:.12em;color:#889273;margin-top:24px}.editorial-finale{background:#e1eeac;text-align:center;padding:66px 0 58px;border-top:1px solid #d3dfa1}.finale-star{display:block;font-size:48px;line-height:1;margin-bottom:23px}.editorial-finale h2{font-size:clamp(32px,4vw,53px);line-height:1.5;font-weight:500;margin:23px 0 30px}.editorial-finale .eyebrow{color:#637044}.editorial-finale .btn-outline{background:transparent;border-color:#81935b}.editorial-finale .container>div{display:flex;justify-content:center;gap:12px}.editorial-finale p{font-size:11px;color:#6e7d4b;letter-spacing:.15em;margin:26px 0 0}
@media(min-width:1450px){.editorial-hero-grid{padding-top:67px;padding-bottom:60px}.editorial-copy h1{font-size:78px}.intuition-lab{padding-top:28px}.lab-plot .graph-svg{height:245px}}
@media(max-width:1100px){.editorial-hero-grid{gap:35px}.editorial-copy h1{font-size:5.5vw}.intuition-lab{padding-inline:20px}.lab-stamp{right:-9px}.path-layout{gap:35px;grid-template-columns:.8fr 1.8fr}.path-tile{padding-inline:20px}.path-intro h2{font-size:29px}.editorial-notes-grid{gap:65px}.course-grid{grid-template-columns:repeat(2,minmax(0,1fr))}.editorial-courses .course-card-cover{height:230px}.method-title>p{position:static}.header-inner{height:74px}.nav-link.active:after{bottom:-28px}}
@media(max-width:760px){.hero-kicker{padding-top:23px;font-size:8px}.hero-kicker>span:last-child{font-size:9px;letter-spacing:0}.editorial-hero-grid{grid-template-columns:1fr;gap:39px;padding-top:35px;padding-bottom:40px}.editorial-copy h1{font-size:clamp(47px,8.6vw,67px);line-height:1.35}.edition-label{font-size:11px;margin-bottom:18px}.editorial-copy>p{font-size:13px}.editorial-actions{gap:22px}.hero-footnote{margin-top:27px}.intuition-lab{margin:0 8px 0 2px;transform:rotate(.8deg)}.lab-caption h2{font-size:22px}.lab-plot .graph-svg{height:auto;max-height:240px}.lab-stamp{right:-12px;top:52px}.hero-index{font-size:7px}.hero-index>span:nth-child(3){display:none}.path-section{padding:57px 0}.path-layout{grid-template-columns:1fr;gap:27px}.path-intro h2{font-size:31px;margin-top:16px}.path-intro h2 br{display:none}.path-intro>p{font-size:12px;display:inline}.path-intro>p br{display:none}.path-intro>.text-link{display:flex;max-width:max-content}.path-options{gap:15px}.path-tile{padding:17px 17px 0}.path-tile-top{font-size:8px;gap:8px}.path-illustration{height:122px;font-size:85px}.path-equals{font-size:30px}.path-illustration sup{font-size:32px}.path-illustration:after{inset:20px 10px}.path-tile-university .path-illustration:after{inset:25px}.path-tile-copy h3{font-size:23px}.path-tile-copy p{font-size:10px;min-height:55px}.path-tile-foot{font-size:10px;padding-block:15px}.editorial-courses{padding:57px 0}.section-top h2{font-size:31px}.editorial-courses .course-card-cover{height:180px}.course-card h3{font-size:18px}.collection-note{display:block}.collection-note p{margin-top:8px;line-height:1.9}.editorial-method{padding:59px 0}.method-title h2{font-size:34px}.method-panels{gap:23px;margin-top:33px}.method-panel h3{font-size:17px;line-height:1.6}.method-panel p{font-size:11px}.editorial-notes{padding:66px 0}.editorial-notes-grid{gap:47px;grid-template-columns:1fr}.note-preview{max-width:450px;width:calc(100% - 16px);margin:auto}.editorial-notes-copy h2{font-size:36px}.editorial-finale{padding:50px 0}.editorial-finale h2{font-size:34px}.header-inner{height:67px}.mobile-nav{background:#f8f8f2}.course-detail-top h1{font-size:44px}}
@media(max-width:480px){.container{width:calc(100% - 36px)}.brand-name{font-size:22px}.header-actions{gap:8px}.editorial-copy h1{font-size:clamp(40px,10.5vw,50px)}.hero-kicker>span:last-child{font-size:8px}.edition-label{font-size:10px}.editorial-copy>p{font-size:12px}.editorial-actions{gap:20px}.editorial-actions .btn{font-size:12px;padding:14px 16px;gap:12px}.editorial-secondary{font-size:11px;gap:8px}.hero-footnote{font-size:10px}.intuition-lab{padding-inline:18px;box-shadow:7px 9px 0 #dfe5ce}.lab-top{font-size:7px}.lab-caption{padding-top:24px}.lab-caption h2{font-size:20px}.lab-stamp{font-size:13px;padding:12px;top:56px}.lab-stamp em{font-size:19px}.lab-plot .interactive-value{font-size:10px;padding:5px 9px}.lab-plot .interactive-value strong{font-size:14px}.lab-plot .range-row{gap:9px;font-size:9px}.lab-bottom{font-size:9px}.path-options{grid-template-columns:1fr}.path-tile{display:grid;grid-template-columns:1fr 120px;position:relative;padding:20px 22px 0}.path-tile-top{grid-column:1/-1}.path-illustration{grid-column:2;grid-row:2;height:126px;align-self:center}.path-tile-copy{grid-column:1;grid-row:2}.path-tile-copy h3{font-size:26px;margin:22px 0 10px}.path-tile-copy p{min-height:0;max-width:175px;font-size:11px}.path-tile-foot{margin-top:13px;margin-bottom:0;gap:15px;max-width:175px}.path-intro h2{font-size:29px}.course-grid{grid-template-columns:1fr;gap:23px}.editorial-courses .course-card-cover,.course-card-cover{height:220px}.course-card-body{padding:22px}.course-card h3{font-size:23px}.course-card-meta{font-size:10px}.course-card p{min-height:0;font-size:12px}.course-card-foot{font-size:11px}.section-top h2{font-size:29px}.method-title h2{font-size:28px}.method-panels{grid-template-columns:1fr;gap:28px}.method-panel{display:grid;grid-template-columns:52px 1fr;column-gap:19px;padding-top:22px}.method-panel>div{grid-row:1/3;flex-direction:column;justify-content:flex-start;gap:13px}.method-panel>div span{font-size:8px;line-height:1.7;letter-spacing:0;text-align:center}.method-panel b{font-size:34px}.method-panel h3{font-size:20px;margin:0 0 10px}.method-panel p{font-size:12px}.note-preview{padding:23px 23px 0}.note-equation{font-size:20px}.note-preview h3{font-size:31px}.editorial-notes-copy h2{font-size:33px}.editorial-finale h2{font-size:29px}.editorial-finale .btn{font-size:12px;padding:13px 17px}.footer-links{flex-wrap:wrap;gap:30px}.footer-links>div:last-child{width:100%}.site-footer{padding-top:45px}.stage-choice{padding:12px 13px}.catalog-stage-heading h2{font-size:23px}.page-hero h1{font-size:37px}.course-detail-top h1{font-size:39px}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}
/* Keep the wordmark punctuation on its baseline at every size. */
.brand-mark{display:flex;align-items:baseline;justify-content:center;gap:0;padding:0 3px 0 0;line-height:38px}.brand-mark .brand-dot{display:inline;color:inherit;font-size:20px;line-height:1}.site-footer .brand-mark .brand-dot{color:inherit}
@media(max-width:700px){.brand-mark{line-height:34px}}
/* Collection index and course spread */
.catalog-opening{background:#eeefe4;border-bottom:1px solid #dce1cf;padding:48px 0 43px}.catalog-opening>.container{display:flex;justify-content:space-between;gap:35px;align-items:center}.catalog-opening h1{font-size:clamp(39px,4.1vw,58px);font-weight:500;line-height:1.4;margin:17px 0 0}.catalog-opening h1>span{color:#6a7e56}.catalog-opening-aside{width:255px;padding-left:25px;border-left:1px solid #cfd7bf}.catalog-emblem{font-size:40px;line-height:1;color:#62794c}.catalog-opening-aside p{font-size:12px;color:#6b795e;line-height:2;margin:19px 0 14px}.catalog-opening-aside small{font-size:8px;letter-spacing:.12em;color:#7c8868}.catalog-layout{padding-top:32px}.academic-stage-filter{gap:10px}.stage-choice{font-size:12px;padding:12px 22px;min-height:46px}.course-detail-top{color:#173d2f;border-bottom:1px solid #dce1cf}.course-detail-top .breadcrumbs{color:#718060}.course-detail-top .eyebrow{color:#5b7247}.course-detail-top h1 span{color:#647e51}.course-detail-lead,.course-detail-facts span{color:#6c7b61}.detail-buttons .btn-ghost-light{border:1px solid #9eaf89;background:transparent;color:#33523b}.detail-buttons .btn-ghost-light:hover{background:#e1e6cf}.detail-art{border-radius:4px;border-color:#456546;box-shadow:10px 12px 0 #dce1cb}.detail-art .course-art{filter:saturate(.65)}.syllabus{border-radius:4px}.syllabus-section-head{background:#edf0e4}.preview-pill{background:#e4ebc8;color:#475e2c}.purchase-preview>span{background:#e0ecb5;color:#355130;box-shadow:none}.purchase-preview{border-radius:0}.lesson-sidebar{top:83px;height:calc(100vh - 83px)}
@media(max-width:950px){.lesson-sidebar{top:74px;height:calc(100vh - 74px)}}
@media(max-width:700px){.catalog-opening{padding:35px 0 29px}.catalog-opening h1{font-size:37px}.catalog-opening-aside{width:180px;padding-left:18px}.catalog-opening-aside p{font-size:10px}.catalog-emblem{font-size:32px}.course-detail-top h1{font-size:43px}.lesson-sidebar{position:relative;top:0;height:auto}.lesson-tabs{top:67px}}
@media(max-width:480px){.catalog-opening>.container{display:block}.catalog-opening h1{font-size:36px}.catalog-opening-aside{width:auto;border:0;padding:0;margin-top:20px}.catalog-opening-aside p{font-size:11px;margin:0}.catalog-opening-aside p br{display:none}.catalog-emblem,.catalog-opening-aside small{display:none}.catalog-layout{padding-top:23px}.stage-choice{font-size:11px;padding:11px 10px}.course-detail-top h1{font-size:39px}.detail-art{box-shadow:6px 7px 0 #dce1cb}}