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@media(max-width:1080px){.main-nav{gap:12px;font-size:10px}.brand{min-width:205px}.brand img{width:55px;height:55px}.brand-copy strong{font-size:10px}.nav-about{padding-left:12px}.hero{min-height:530px}.hero-art{height:370px}.path-card{padding-inline:16px}.olympiad-layout{gap:45px}.archive-wrap{gap:35px}.lab-grid{gap:45px}}
@media(max-width:820px){.wrap{width:min(var(--max),calc(100% - 40px))}.header-inner{height:74px}.brand{min-width:0}.brand img{width:50px;height:50px}.brand-copy strong{font-size:10px}.main-nav{display:none;position:absolute;left:0;right:0;top:100%;padding:10px 20px 20px;background:#fff;border-bottom:1px solid var(--line);box-shadow:0 12px 20px rgba(16,39,70,.08);align-items:stretch;flex-direction:column;gap:0}.main-nav.open{display:flex}.nav-link,.nav-about{padding:12px 0;border-bottom:1px solid #edf1f5;border-left:0}.nav-about{padding-left:0}.menu-toggle{display:flex;width:42px;height:42px;border:1px solid var(--line);background:#fff;flex-direction:column;align-items:center;justify-content:center;gap:5px;cursor:pointer}.menu-toggle>span{height:1px;width:17px;background:var(--blue-night)}.hero{grid-template-columns:1.1fr .9fr;min-height:495px;padding-top:48px}.hero h1{font-size:clamp(40px,6.8vw,60px)}.hero-art{height:320px}.hero-art-frame{width:min(285px,82%)}.hero-note{bottom:25px}.intro-grid{grid-template-columns:.6fr 1.6fr;gap:22px;padding:50px 0}.intro-aside{grid-column:2;border-left:0;border-top:1px solid #d9e2ec;padding:17px 0 0;display:grid;grid-template-columns:auto 1fr;align-items:center;column-gap:12px}.intro-aside p{margin:0}.intro-aside .aside-rule,.intro-aside .aside-caption{display:none}.path-grid{grid-template-columns:repeat(2,1fr)}.path-card:nth-child(2){border-right:0}.path-card:nth-child(-n+2){border-bottom:1px solid var(--line)}.path-feature{background:var(--blue-deep)}.section{padding-block:70px}.olympiad-layout{grid-template-columns:.7fr 1.3fr;gap:25px}.topic-layout{grid-template-columns:1.4fr .7fr}.topic-row{grid-template-columns:35px 1fr 22px}.topic-row span:nth-child(3){display:none}.archive-wrap{grid-template-columns:.55fr 1.45fr;gap:24px}.archive-intro h2{font-size:34px}.problem-row{grid-template-columns:70px 1fr 15px;gap:10px;padding:17px 12px}.lab-grid{grid-template-columns:.8fr 1.2fr;gap:28px}.lab-copy h2{font-size:38px}.journal-grid{gap:16px}.journal-art{height:150px}.community-inner{align-items:flex-start}.community-right{align-items:flex-start;flex-direction:column;gap:14px}.footer-main{gap:30px}.footer-nav{gap:20px}}
@media(max-width:600px){.wrap{width:calc(100% - 36px)}.topline{font-size:8px;letter-spacing:.11em}.topline-inner{min-height:31px}.language-switch{gap:5px}.header-inner{height:68px}.brand img{width:44px;height:44px}.brand{gap:8px}.brand-copy strong{font-size:9px}.brand-copy small{font-size:9px}.hero{display:flex;flex-direction:column;align-items:stretch;padding-top:42px;min-height:0}.hero-copy{padding-bottom:8px}.hero h1{font-size:clamp(40px,11vw,58px)}.hero-lede{font-size:14px}.hero-meta{margin-top:28px}.hero-art{height:auto;min-height:295px;margin:7px 3px 16px}.hero-art:before{inset:10px 8px 15px 16px}.hero-art-frame{width:min(230px,64%)}.hero-note{left:0;bottom:14px;font-size:13px}.hero-index{right:0;top:1px}.hero-bottomline{font-size:8px;height:40px;letter-spacing:.1em}.intro-grid{display:block;padding:41px 0}.section-marker{margin-bottom:26px}.intro-main h2,.section-heading h2,.archive-intro h2,.lab-copy h2,.community-inner h2{font-size:34px}.intro-main p{font-size:13px}.intro-aside{margin-top:26px;display:flex;gap:13px;padding-top:14px}.aside-number{font-size:27px}.intro-aside p{font-size:15px}.section{padding-block:58px}.section-heading{display:block;margin-bottom:24px}.heading-note{margin-top:13px}.section-heading>.text-link{margin-top:14px}.path-grid{grid-template-columns:1fr 1fr}.path-card{min-height:215px;padding:15px 13px}.card-index{font-size:8px}.path-icon{margin-top:24px;margin-bottom:10px}.path-card h3{font-size:16px}.path-card p{font-size:10px;padding-right:6px}.card-arrow{right:12px;bottom:12px}.olympiad-section{padding:58px 0}.olympiad-layout{grid-template-columns:1fr;gap:28px}.big-outline{font-size:80px}.olympiad-lead{display:grid;grid-template-columns:.5fr 1fr;gap:0 12px;align-items:center}.olympiad-lead .big-outline{grid-row:span 2}.olympiad-lead p{margin:0 0 13px;font-size:11px}.olympiad-lead .button{justify-self:start;min-height:40px;padding-inline:12px;font-size:10px}.olympiad-row{min-height:77px;grid-template-columns:27px 1fr 17px;gap:9px;padding-inline:4px}.row-main strong{font-size:12px}.row-main small{font-size:9px}.row-state{display:none}.topic-layout{grid-template-columns:1fr}.topic-list{border-right:0}.topic-row{min-height:65px;grid-template-columns:31px 1fr 19px;padding-right:4px}.topic-row strong{font-size:12px}.topic-aside{padding:23px 0 0;border-top:1px solid var(--line);margin-top:6px}.archive-section{padding:56px 0}.archive-wrap{grid-template-columns:1fr;gap:20px}.archive-intro{position:static}.archive-intro h2{font-size:34px;margin-bottom:9px}.archive-intro>p:not(.eyebrow){max-width:440px;font-size:12px}.archive-breadcrumb{margin-top:17px}.archive-tools{height:auto;padding:9px;gap:7px}.search-box{height:39px;gap:5px;padding-inline:7px}.search-box kbd{display:none}.filter-button{padding-inline:9px;gap:9px;font-size:10px}.problem-row{grid-template-columns:1fr 16px;gap:6px;padding:16px 12px}.problem-no{grid-column:1/-1;padding:0}.problem-content h3{font-size:13px}.problem-content>p{font-size:10px}.archive-footer{padding:10px 12px}.archive-footer>span{font-size:8px}.lab-section{padding:56px 0}.lab-grid{grid-template-columns:1fr;gap:28px}.lab-copy h2{font-size:36px}.lab-copy>p:not(.eyebrow){font-size:12px}.lab-board-wrap{padding:13px}.lab-board{width:min(100%,300px);max-height:290px;margin:15px auto}.journal-grid{grid-template-columns:1fr;gap:29px}.journal-art{height:185px}.journal-card h3,.journal-feature h3{font-size:16px}.journal-feature>p,.journal-card>p{font-size:11px}.community-band{padding:43px 0}.community-inner{display:block}.community-inner h2{font-size:33px}.community-right{margin-top:23px}.footer-main{display:block;padding:35px 0 28px}.footer-nav{margin-top:30px;grid-template-columns:repeat(2,1fr);gap:22px}.footer-nav>div:last-child{grid-column:1/-1}.footer-bottom{height:auto;min-height:58px;gap:8px;flex-wrap:wrap;padding-block:10px;font-size:7px;letter-spacing:.06em}.footer-bottom>span:nth-child(2){display:none}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{transition:none!important;animation:none!important}}

/* Structured navigation and quiz module */
.nav-group summary{font-size:12px;font-weight:600}.quiz-section{background:#fff;padding:80px 0;border-bottom:1px solid var(--line)}.quiz-grid{display:grid;grid-template-columns:.75fr 1.25fr;gap:70px;align-items:center}.quiz-intro h2{font:700 clamp(34px,4vw,46px)/1.12 var(--display);letter-spacing:-.045em;color:var(--blue-night);margin:0 0 17px}.quiz-intro>p:not(.eyebrow){font-size:12px;line-height:1.8;color:#63758b;max-width:350px;margin-bottom:17px}.quiz-card{border:1px solid var(--line);padding:24px 25px 17px;background:#fff;box-shadow:0 8px 26px rgba(19,53,91,.05)}.quiz-card-head,.quiz-card-foot{display:flex;align-items:center;justify-content:space-between;color:#7c8da1;font-size:8px;font-weight:700;letter-spacing:.13em}.quiz-card-head{padding-bottom:15px;border-bottom:1px solid #e9eef4}.quiz-card-head span:first-child{color:var(--blue-deep)}.quiz-card h3{font:700 19px/1.45 var(--display);letter-spacing:-.02em;color:var(--blue-night);margin:19px 0}.quiz-options{display:grid;grid-template-columns:repeat(3,1fr);gap:9px}.quiz-options button{min-height:47px;text-align:left;border:1px solid #d7e2ee;background:#fff;padding:10px 12px;font-size:10px;color:#526880;cursor:pointer}.quiz-options button:hover,.quiz-options button.selected{border-color:var(--blue);color:var(--blue-deep);background:#f4f8fe}.quiz-options button.correct{border-color:#23835b;background:#eff9f4;color:#176541}.quiz-options button.incorrect{border-color:#b95757;background:#fff5f4;color:#903d3d}.quiz-feedback{min-height:22px;font-size:10px;color:#6d7e91;margin:13px 0}.quiz-feedback.correct{color:#176541}.quiz-feedback.incorrect{color:#903d3d}.quiz-card-foot{border-top:1px solid #e9eef4;padding-top:12px;font-weight:500;letter-spacing:.04em}.quiz-mark{color:var(--blue-deep);font-weight:700}.filter-row[hidden],.problem-row[hidden]{display:none!important}
@media(max-width:1080px){.main-nav{gap:10px;font-size:10px}.nav-group summary{font-size:10px}.nav-about{padding-left:10px}.brand{min-width:190px}}
@media(max-width:820px){.nav-group{border-bottom:1px solid #edf1f5}.nav-group summary{padding:12px 0;font-size:12px}.nav-group summary:after{top:10px;right:4px}.nav-dropdown{position:static;box-shadow:none;border:0;border-top:1px solid #edf1f5;padding:3px 0 5px 12px}.nav-dropdown a{padding:9px 8px}.quiz-grid{grid-template-columns:.8fr 1.2fr;gap:28px}.quiz-card{padding:20px}.quiz-options{grid-template-columns:1fr}.quiz-options button{min-height:39px}}
@media(max-width:600px){.quiz-section{padding:56px 0}.quiz-grid{grid-template-columns:1fr;gap:25px}.quiz-intro h2{font-size:36px}.quiz-card{padding:18px 14px 14px}.quiz-card h3{font-size:16px;margin:15px 0}.quiz-options{grid-template-columns:1fr;gap:7px}.quiz-options button{min-height:40px}.quiz-card-head,.quiz-card-foot{font-size:7px}}

/* Hidden application states must stay hidden even on flex/grid panels. */
[hidden]{display:none!important}