@charset "UTF-8";
:root{--paper:#f6f5ef;--card:#fff;--ink:#26372f;--muted:#5f6c62;--line:#dfe5dd;--teal:#206d50;--light:#edf3ed;--gold:#d8b66d;--forest:#153f33;--navy:#153f33;--danger:#a13f39;--reading-size:18px;--radius:16px;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;font-synthesis:none;line-height:1.55;color:var(--ink);background:var(--paper)}
*{box-sizing:border-box}html{scroll-padding-top:24px}body{margin:0;background:var(--paper);color:var(--ink)}body.dark{--paper:#10251e;--card:#193128;--ink:#e6eee7;--muted:#a4b6aa;--line:#334a3c;--teal:#9fd5b6;--light:#243e30;--forest:#1f4939;--navy:#10271f;--danger:#f2aba3;color-scheme:dark}a{color:var(--teal);text-decoration:none}button,input,select,textarea{font:inherit}button{cursor:pointer}button:disabled{opacity:.5;cursor:default}a,button,input,select,textarea,summary{-webkit-tap-highlight-color:transparent}a:focus-visible,button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible,summary:focus-visible{outline:3px solid #be903b;outline-offset:4px}input,select,textarea{max-width:100%;min-height:48px;border:1px solid #cbd5ca;border-radius:9px;padding:11px 13px;color:var(--ink);background:var(--card)}body.dark input,body.dark select,body.dark textarea{border-color:var(--line)}input[type=checkbox],input[type=radio]{accent-color:var(--teal);height:20px;width:20px;min-height:20px;padding:0;flex-shrink:0}textarea{width:100%;min-height:210px;resize:vertical;line-height:1.8}select{cursor:pointer}label{display:block}h1,h2,h3,h4,p{margin-top:0}h1,h2,h3,h4{line-height:1.2;letter-spacing:-.035em;font-weight:650}h1{font-family:Georgia,"Times New Roman",serif;font-weight:400;font-size:clamp(34px,3.4vw,49px);margin-bottom:18px}h2{font-size:25px}h3{font-size:18px}p{margin-bottom:18px}img{max-width:100%;height:auto}small,.small{font-size:12px}.muted{color:var(--muted)}.eyebrow{display:block;color:var(--teal);font-size:10px;line-height:1.6;letter-spacing:.13em;font-weight:700;text-transform:uppercase;margin-bottom:14px}.icon{width:22px;height:22px;flex-shrink:0;display:inline-block;fill:none;stroke:currentColor;stroke-width:1.65;stroke-linecap:round;stroke-linejoin:round;vertical-align:middle}.icon-sprite{position:absolute;width:0;height:0;overflow:hidden;pointer-events:none}.row,.between{display:flex;gap:16px;align-items:center;flex-wrap:wrap}.between{justify-content:space-between}.actions{display:flex;gap:10px;align-items:center;flex-wrap:wrap}.intro{margin-bottom:32px}.intro h1{max-width:940px}.intro p{max-width:750px;font-size:14px;line-height:1.85;margin-bottom:0}.skip{position:fixed;z-index:100;left:12px;top:10px;transform:translateY(-150%);background:var(--forest);color:#fff;padding:12px 18px;border-radius:8px}.skip:focus{transform:translateY(0)}
/* A quiet, permanent desktop spine. */
.sidebar{position:fixed;inset:0 auto 0 0;z-index:25;width:250px;padding:32px 22px 23px;background:#153f33;color:#e4eee3;display:flex;flex-direction:column;overflow-y:auto}.brand{display:flex;align-items:center;gap:11px;font-size:25px;font-weight:750;letter-spacing:-.045em;color:inherit}.brand img{width:49px;height:49px;object-fit:contain;border-radius:12px;flex-shrink:0;background:#151412}.brand b{font-size:12px;letter-spacing:.06em;color:var(--gold);vertical-align:middle}.brand small{display:block;font-size:9px;letter-spacing:0;font-weight:400;color:#a9bfb1;margin-top:4px}.nav-heading{font-size:9px;color:#94b4a0;letter-spacing:.17em;font-weight:650;margin:48px 13px 15px}.nav-links{display:grid;gap:7px}.nav-links a{display:flex;align-items:center;gap:13px;min-height:49px;padding:13px 14px;border-radius:10px;color:#c3d5c7;font-size:13px;font-weight:500}.nav-links a .icon{width:20px;height:20px}.nav-links a:hover{color:#fff;background:#ffffff0c}.nav-links a.active{color:#163f32;background:#f4f3e9;box-shadow:0 4px 14px #00150c0a;font-weight:650}.sidebar-foot{margin-top:auto;padding:34px 13px 0;color:#a5bfae}.sidebar-foot>.icon{color:var(--gold);width:25px;height:25px;margin-bottom:15px;stroke-width:1.3}.sidebar-foot p{font:21px/1.55 Georgia,"Times New Roman",serif;letter-spacing:-.02em;color:#e5e9db;margin-bottom:24px}.sidebar-offline{display:flex;gap:7px;align-items:center;font-size:10px;line-height:1.5}.sidebar-offline i,.offline i{width:5px;height:5px;border-radius:50%;background:#93bc91;display:block}.sidebar-foot>small{display:flex;align-items:center;justify-content:space-between;border-top:1px solid #ffffff1c;font-size:9px;letter-spacing:.12em;padding-top:16px;margin-top:20px}.sidebar-foot>small span{letter-spacing:0;font-size:10px;color:#bbcfbe}.shell{margin-left:250px}.topbar{min-height:84px;padding:16px 43px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;gap:18px;background:var(--paper)}.breadcrumb{color:var(--muted);font-size:12px}.topbar-tools{display:flex;align-items:center;gap:27px;margin-left:auto}.offline{display:flex;align-items:center;gap:7px;font-size:10px;color:var(--muted);white-space:nowrap}.header-institute{display:flex;align-items:center;gap:11px;flex-shrink:0;color:var(--ink);font-size:9px;line-height:1.5}.header-institute img{width:46px;height:46px;object-fit:contain;flex-shrink:0;background:#fff;border-radius:50%;padding:2px}.header-institute b{font-size:11px;font-weight:650}.mobile-brand{display:none}main,#main{max-width:1330px;margin:0 auto;padding:43px 43px 54px;min-height:calc(100vh - 172px)}main>*,main section,main article{min-width:0}.footer{border-top:1px solid var(--line);padding:23px 43px 27px;display:flex;align-items:center;justify-content:space-between;gap:24px;color:var(--muted);font-size:10px;line-height:1.9}.footer b{font-weight:600;color:var(--ink)}.footer a{display:flex;align-items:center;gap:8px;min-height:44px;font-size:11px}.footer .icon{width:16px;height:16px}.bottom-nav{display:none}
/* Shared surfaces and controls. */
.btn{display:inline-flex;align-items:center;justify-content:center;gap:9px;min-height:46px;padding:11px 18px;border:1px solid var(--teal);border-radius:9px;background:var(--teal);color:#fff;font-size:12px;font-weight:600;line-height:1.5;text-align:center;max-width:100%}.btn .icon{width:18px;height:18px}.btn:hover{filter:brightness(.94)}.btn.secondary{color:var(--ink);background:var(--card);border-color:var(--line)}.btn.secondary:hover{border-color:var(--teal);background:var(--light)}.btn.ghost{color:var(--teal);background:transparent;border-color:transparent}.btn.danger{background:transparent;border-color:#d7aba4;color:var(--danger)}.btn.gold{background:var(--gold);border-color:var(--gold);color:#153f33}.btn.wide{width:100%}.btn.sm{font-size:11px;padding:9px 12px}.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:27px}.grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:15px}.section-head{display:flex;justify-content:space-between;align-items:center;gap:15px;flex-wrap:wrap;margin:36px 0 20px}.section-head h2{margin:0;font-size:24px;letter-spacing:-.04em}.section-caption{color:var(--muted);font-size:11px}.tag{display:inline-block;padding:5px 9px;border-radius:5px;background:var(--light);color:var(--teal);font-size:10px;line-height:1.5;font-weight:600}.empty{padding:38px 24px;border:1px dashed var(--line);border-radius:var(--radius);text-align:center;color:var(--muted);font-size:14px}.empty>.icon{width:30px;height:30px;color:var(--teal);margin-bottom:18px}.empty h3{color:var(--ink);font-size:19px;margin-bottom:9px}.empty p{font-size:13px;margin-bottom:20px}.callout{display:flex;align-items:flex-start;gap:13px;padding:19px 21px;margin:24px 0;border:1px solid var(--line);border-left:3px solid var(--teal);background:var(--light);border-radius:0 11px 11px 0;font-size:13px;line-height:1.85}.callout .icon{width:19px;height:19px;margin-top:3px}.callout p:last-child{margin-bottom:0}.progress-fill{height:5px;border-radius:6px;background:var(--line);overflow:hidden;margin:16px 0 10px}.progress-fill i,.progress-fill>span{display:block;height:100%;border-radius:6px;background:var(--teal)}
/* The home is a learning desk, with real progress at a glance. */
.home-hero{display:grid;grid-template-columns:1.3fr 1fr;gap:46px;align-items:center}.hero-copy{padding:9px 0 12px}.hero-copy .eyebrow{font-size:9px;letter-spacing:.14em;margin-bottom:20px}.hero-copy h1{font-size:clamp(47px,4.9vw,70px);letter-spacing:-.06em;line-height:1.08;margin-bottom:22px}.hero-copy h1 em{color:var(--teal);font-weight:400}.hero-copy>p{max-width:440px;color:var(--muted);font-size:14px;line-height:1.9;margin-bottom:25px}.hero-credit{font-size:10px;font-weight:600;color:var(--ink)}.hero-credit span{margin:0 7px;color:var(--gold)}.journey-card{position:relative;overflow:hidden;border:1px solid var(--line);border-radius:20px;padding:26px;background:var(--card)}.journey-card:before{content:"";position:absolute;width:180px;height:180px;border:1px solid var(--line);border-radius:50%;right:-90px;top:-90px;box-shadow:0 0 0 24px var(--card),0 0 0 25px var(--line),0 0 0 49px var(--card),0 0 0 50px var(--line);opacity:.55;pointer-events:none}.journey-mark{display:flex;width:39px;height:39px;align-items:center;justify-content:center;background:#f5eddb;border-radius:50%;color:#9d7c3a;margin-bottom:18px}.journey-mark .icon{width:23px;height:23px;stroke-width:1.3}.journey-card>.eyebrow{font-size:8px;margin-bottom:11px;position:relative}.journey-card h2{font:29px/1.18 Georgia,"Times New Roman",serif;letter-spacing:-.035em;margin:0 0 24px;position:relative}.journey-numbers{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:11px}.journey-numbers>div+div{border-left:1px solid var(--line);padding-left:13px}.journey-numbers b{display:block;font-size:24px;line-height:1.2;font-weight:550;letter-spacing:-.05em}.journey-numbers small{font-size:10px;color:var(--muted);font-weight:400;letter-spacing:0;white-space:nowrap}.journey-numbers span{display:block;color:var(--muted);font-size:9px;margin-top:8px;white-space:nowrap}.journey-card>.btn{margin:21px 0 -8px;padding-left:0;padding-right:0;font-size:11px;min-height:40px}.stats{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px}.collection-stats{border-top:1px solid var(--line);border-bottom:1px solid var(--line);padding:22px 0;margin:32px 0 0;gap:0}.stat{min-width:0}.collection-stats .stat{display:flex;align-items:baseline;gap:13px;padding-left:27px}.collection-stats .stat:first-child{padding-left:0}.collection-stats .stat+.stat{border-left:1px solid var(--line)}.stat b{font:35px/1.2 Georgia,"Times New Roman",serif;color:var(--ink);letter-spacing:-.04em}.stat span{font-size:11px;color:var(--muted)}.study-grid{display:grid;grid-template-columns:1.12fr 1fr;gap:20px;align-items:stretch}.resume-card{display:flex;flex-direction:column;min-height:329px;padding:29px 30px 26px;border-radius:var(--radius);background:var(--forest);color:#f0f2e5;position:relative;overflow:hidden}.resume-card:after{content:"";position:absolute;width:270px;height:270px;border:1px solid #d1dbc51c;border-radius:50%;right:-175px;top:55px;box-shadow:0 0 0 32px #ffffff04,0 0 0 33px #d1dbc50c;pointer-events:none}.resume-top{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-bottom:12px}.resume-top .eyebrow{color:#d6c88e;font-size:8px;margin:0;letter-spacing:.12em}.resume-symbol{width:34px;height:34px;display:flex;align-items:center;justify-content:center;border:1px solid #ffffff26;border-radius:8px;color:#cbdcbd}.resume-symbol .icon{width:19px;height:19px}.resume-chapter{font:42px/1.1 Georgia,"Times New Roman",serif;color:#d8c78f;letter-spacing:-.04em;margin-bottom:13px}.resume-chapter>span{font:9px/1.5 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;letter-spacing:.12em;color:#a8bfac;vertical-align:middle;margin-left:7px}.resume-card h2{font:29px/1.22 Georgia,"Times New Roman",serif;letter-spacing:-.035em;max-width:410px;margin-bottom:12px;position:relative;z-index:1}.resume-card>p{font-size:11px;color:#b6c9b8;margin-bottom:23px;position:relative;z-index:1}.resume-bottom{margin-top:auto;padding-top:16px;border-top:1px solid #ffffff21;display:flex;align-items:center;justify-content:space-between;gap:13px;position:relative;z-index:1}.resume-bottom>span{font-size:12px;font-weight:550;display:flex;align-items:center;gap:10px}.resume-bottom .icon{width:18px;height:18px}.resume-bottom small{font-size:9px;color:#b5c5af;white-space:nowrap}.resume-card .progress-fill{margin:17px 0 0;background:#ffffff1c;height:3px}.resume-card .progress-fill i{background:var(--gold)}.study-actions{display:grid;grid-template-rows:repeat(3,1fr);gap:10px}.study-action{display:flex;align-items:center;gap:16px;padding:20px;background:var(--card);border:1px solid var(--line);border-radius:13px;color:var(--ink);min-width:0}.study-action>div{flex:1;min-width:0}.action-icon{display:flex;align-items:center;justify-content:center;width:43px;height:43px;flex-shrink:0;border-radius:11px;background:var(--light);color:var(--teal)}.action-icon .icon{width:21px;height:21px}.study-action .eyebrow{font-size:8px;margin-bottom:5px;color:var(--muted);letter-spacing:.12em}.study-action h3{font-size:16px;margin-bottom:5px;letter-spacing:-.025em}.study-action p{font-size:11px;color:var(--muted);line-height:1.6;margin:0}.study-action>.icon{width:18px;height:18px;color:var(--muted)}.study-action:hover{border-color:#9eb6a2;background:var(--light)}
/* Chapter collection. */
.library-toolbar{display:flex;align-items:center;justify-content:space-between;gap:20px;margin:0 0 23px;padding:0 0 22px;border-bottom:1px solid var(--line)}.library-total{font-size:12px;color:var(--muted);white-space:nowrap}.library-total>span{margin:0 8px;color:#a7b5a7}.search-field{display:flex;align-items:center;position:relative;width:310px}.search-field>.icon{position:absolute;left:14px;width:18px;height:18px;color:var(--muted);pointer-events:none}.search-field input{width:100%;padding-left:42px;font-size:12px;background:var(--card)}.chapters-grid{gap:14px}.chapter-card{display:flex;align-items:flex-start;gap:21px;min-height:146px;color:var(--ink);padding:24px 23px;border-radius:13px}.chapter-card:hover{border-color:#a1b7a3;background:var(--light)}.chapter-no{font:34px/1.1 Georgia,"Times New Roman",serif;letter-spacing:-.06em;color:#91a38d;min-width:35px;padding-top:2px}.chapter-info{min-width:0;flex:1}.chapter-info small{font-size:10px;color:var(--muted);display:block;margin-bottom:10px}.chapter-info h3{font-size:17px;line-height:1.4;letter-spacing:-.03em;margin-bottom:16px}.chapter-state{display:flex;align-items:center;gap:8px;font-size:10px;color:var(--teal);font-weight:550}.chapter-state .icon{width:15px;height:15px}.chapter-card.is-read .chapter-no{color:var(--teal)}.chapter-card.is-read{border-top-color:#91b79a}
/* Reading and complete, self-contained problem statements. */
.reading-page{max-width:900px;margin:0 auto}.reader-toolbar,.reader-nav{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:12px}.reader-toolbar{margin:-9px -8px 28px}.reader-toolbar .btn{font-size:11px;padding:9px 12px}.reader-toolbar .tag{font-size:9px;background:transparent;color:var(--muted);letter-spacing:.08em}.reader-nav{margin-top:23px}.reader-nav .btn{font-size:11px}.reading-page .intro{margin-bottom:31px}.reading-page .intro h1{font-size:clamp(32px,3.4vw,45px);line-height:1.17}.reader{padding:37px 40px;background:var(--card);border-radius:14px}.reader>h1{font-size:33px;line-height:1.3}.reader+.card{margin-top:20px}.reading-complete{padding:20px 24px;border-radius:12px}.prose{min-width:0;max-width:100%;overflow-x:auto;overflow-y:hidden;font-family:Georgia,"Times New Roman",serif;font-size:var(--reading-size);line-height:1.9;overflow-wrap:anywhere}.prose p{margin:0 0 20px}.prose h2{font:650 25px/1.4 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;letter-spacing:-.035em;margin:37px 0 20px}.prose h3{font:650 21px/1.4 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;letter-spacing:-.03em;margin:30px 0 16px}.prose h4{font-size:19px;margin:24px 0 14px}.prose ul,.prose ol{padding-left:27px;margin:20px 0}.prose li{padding-left:4px;margin:10px 0}.prose blockquote{margin:24px 0;padding:17px 20px;border-left:3px solid var(--teal);background:var(--light);border-radius:0 9px 9px 0}.prose blockquote p:last-child{margin-bottom:0}.prose figure{max-width:100%;margin:26px 0;overflow-x:auto}.prose figure img,.prose img{display:block;max-width:100%;height:auto;margin:0 auto}.prose figcaption{font:12px/1.8 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;color:var(--muted);margin-top:12px}.prose table{border-collapse:collapse;display:block;max-width:100%;overflow-x:auto;margin:23px 0;font-size:.9em}.prose th,.prose td{border:1px solid var(--line);padding:10px 13px;vertical-align:top}.prose th{background:var(--light)}.prose .box,.prose .studybox,.prose .warningbox,.prose .notebox,.prose .idea,.prose .asosiyfikr,.prose .callout{display:block;padding:18px 21px;border:1px solid var(--line);border-left:3px solid var(--teal);border-radius:0 9px 9px 0;margin:24px 0;background:var(--light);font-size:1em}.prose .theorem,.prose .teorema,.prose .example,.prose .misol{padding:20px 22px;border:1px solid var(--line);border-radius:10px;background:var(--paper);margin:25px 0}.prose .proof{margin:19px 0 27px}.prose pre{max-width:100%;overflow-x:auto;white-space:pre-wrap;font-size:13px}.book-diagram{background:#fff;border-radius:8px;padding:12px}.katex{font-size:1.05em}.katex-display{max-width:100%;overflow-x:auto;overflow-y:hidden;padding:8px 0;margin:20px 0}.katex-display>.katex{width:max-content;min-width:100%}.prose .katex-error{color:var(--danger)!important}.check{display:flex;align-items:center;gap:11px;min-height:44px;font-size:12px;line-height:1.7}.check input{margin:0}.check b{font-weight:600}.problem-filter-panel{border:1px solid var(--line);background:var(--card);padding:18px 22px 22px;border-radius:13px}.filter-heading{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:13px}.filter-heading>span{display:flex;align-items:center;gap:8px;color:var(--ink);font-size:12px;font-weight:600}.filter-heading .icon{width:18px;height:18px}.volume-tabs .btn{font-size:10px;min-height:38px;padding:7px 10px}.filters{display:grid;grid-template-columns:1fr 1.3fr .85fr;align-items:end;gap:13px}.filters label{min-width:0}.filters label>span{display:block;font-size:10px;font-weight:600;color:var(--muted);margin-bottom:7px}.filters input,.filters select{display:block;width:100%;min-width:0;font-size:12px;background:var(--paper);min-height:47px}.result-count{margin:23px 0 15px;font-size:11px}.problem-list{display:grid;gap:13px}.problem-link{display:flex;align-items:flex-start;gap:22px;padding:25px 26px;color:var(--ink);border-radius:13px;min-width:0}.problem-link:hover{border-color:#a2b6a2}.problem-number{flex-shrink:0;display:flex;align-items:center;justify-content:center;min-width:43px;height:35px;padding:0 8px;border:1px solid var(--line);border-radius:7px;font:20px/1.1 Georgia,"Times New Roman",serif;color:var(--teal);letter-spacing:-.04em}.problem-card-body{min-width:0;flex:1}.problem-meta{display:flex;align-items:center;gap:10px;justify-content:space-between;margin:3px 0 12px}.problem-meta small{font-size:10px;color:var(--muted)}.problem-meta .tag{font-size:9px;white-space:nowrap}.problem-caption{display:block;font-size:15px;line-height:1.5;margin:0 0 9px;font-weight:650}.problem-link .prose{font-size:var(--reading-size);line-height:1.85}.problem-link .prose p:last-child{margin-bottom:0}.problem-open{display:flex;align-items:center;gap:8px;font-size:10px;font-weight:550;color:var(--teal);margin-top:18px}.problem-open .icon{width:15px;height:15px}.problem-end{width:30px;height:30px;border-radius:50%;background:var(--light);color:var(--teal);display:flex;align-items:center;justify-content:center;flex-shrink:0}.problem-end .icon{width:16px;height:16px}.problem-link.is-solved .problem-number{color:var(--teal);background:var(--light);border-color:var(--light)}.problem-list>.btn{justify-self:center;margin-top:15px}.problem-sheet{padding:30px 34px}.statement-heading{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-bottom:17px}.statement-heading .eyebrow{margin:0;font-size:9px}.statement-heading .icon{color:var(--muted);width:19px;height:19px}.problem-title{font-size:calc(var(--reading-size) + 1px);line-height:1.9;margin-bottom:0}.problem-title p:last-child{margin-bottom:0}.solved-row{margin-top:25px;padding:16px 17px;background:var(--light);border-radius:9px}details{border:1px solid var(--line);background:var(--card);border-radius:12px;margin:17px 0;overflow:hidden}details.card{padding:0}summary{min-height:59px;padding:18px 23px;font-size:13px;font-weight:600;line-height:1.7;cursor:pointer}details[open]>summary{border-bottom:1px solid var(--line);background:var(--light)}details>.prose{padding:23px 25px 7px}details>div:not(.prose){padding:20px 24px}details .prose p:last-child{margin-bottom:10px}.solution-details>summary{color:var(--teal)}
/* Personal proof notebook, preserving every editor and history control. */
.proof-workspace{margin-top:29px;padding-top:27px;border-top:1px solid var(--line);min-width:0}.proof-workspace h2{font-size:22px;margin:0 0 9px;letter-spacing:-.035em}.proof-workspace .proof-intro{font-size:12px;line-height:1.85;margin-bottom:22px;max-width:650px}.proof-editor{background:var(--paper);border:1px solid var(--line);border-radius:12px;padding:20px}.note-label{font-size:11px;font-weight:650;margin-bottom:12px}.proof-toolbar{display:flex;flex-wrap:wrap;gap:7px;margin-bottom:11px}.proof-toolbar button{min-height:44px;border:1px solid var(--line);border-radius:7px;background:var(--card);padding:9px 11px;font-size:11px;color:var(--teal)}.proof-toolbar button:hover{background:var(--light);border-color:var(--teal)}.proof-editor textarea{min-height:190px;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:14px;line-height:1.85;border-color:#c2cfbf;border-radius:8px}.proof-help{display:block;color:var(--muted);font-size:10px;line-height:1.9;margin:10px 0 15px;overflow-wrap:anywhere}.proof-help code{font:inherit;color:var(--ink)}.proof-preview{padding:16px 18px;border:1px solid var(--line);border-radius:9px;background:var(--card);margin-bottom:17px;min-width:0}.proof-preview>.small{display:block;font-size:9px;text-transform:uppercase;letter-spacing:.11em;color:var(--muted);margin-bottom:10px}.proof-rendered{position:relative;max-width:100%;min-width:0;overflow-wrap:anywhere;overflow-x:auto;overflow-y:hidden}.proof-rendered .katex{position:relative}.proof-plain{white-space:pre-wrap}.proof-rendered .katex-display{margin:13px 0;max-width:100%;overflow-x:auto;overflow-y:hidden}.proof-rendered .proof-math-error{display:block;border-left:2px solid var(--danger);color:var(--danger);padding-left:10px;margin:10px 0;white-space:pre-wrap;font:13px/1.8 ui-monospace,SFMono-Regular,Consolas,monospace}.proof-math-error small{display:block;white-space:normal;font:11px/1.7 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif}.proof-editor-actions{display:flex;align-items:center;flex-wrap:wrap;gap:9px}.proof-save-status{min-height:18px;font-size:10px;line-height:1.8;color:var(--muted);margin:11px 0 0}.proof-save-status.is-error{color:var(--danger)}.proof-comment-list{display:grid;gap:12px;margin-top:24px}.proof-comment{background:var(--card);border:1px solid var(--line);border-left:3px solid #aec2aa;border-radius:10px;padding:19px 21px;min-width:0}.proof-comment-header{display:flex;align-items:baseline;justify-content:space-between;gap:9px;flex-wrap:wrap;margin-bottom:14px}.proof-comment-header strong{font-size:11px;font-weight:650}.proof-comment-header time{font-size:10px;color:var(--muted)}.proof-comment-actions{display:flex;gap:20px;flex-wrap:wrap;margin-top:13px}.proof-text-button{min-height:44px;padding:7px 0;border:0;background:transparent;color:var(--teal);font-size:11px;font-weight:500}.proof-text-button.danger{color:var(--danger)}.proof-delete-confirm{display:flex;align-items:center;flex-wrap:wrap;gap:9px;padding:12px 14px;margin-top:11px;background:var(--paper);border:1px solid var(--line);border-radius:9px;font-size:11px}.proof-delete-confirm .btn{min-height:44px;font-size:11px;padding:9px 12px}.proof-comment.is-editing{border-color:var(--teal)}.proof-comment-empty{font-size:11px;line-height:1.85;color:var(--muted);margin:0}
/* Tests: a clear setup, an uncluttered question, a bounded question map. */
.quiz-hero{padding:0;overflow:hidden;border-radius:18px}.quiz-introduction{display:flex;align-items:flex-start;gap:22px;padding:31px 33px;background:var(--light);border-bottom:1px solid var(--line)}.quiz-hero-icon{display:flex;align-items:center;justify-content:center;width:58px;height:58px;flex-shrink:0;border:1px solid #c9d7c5;border-radius:13px;color:var(--teal);background:var(--card)}.quiz-hero-icon .icon{width:28px;height:28px}.quiz-introduction .eyebrow{font-size:9px;margin-bottom:12px}.quiz-introduction h2{font:35px/1.15 Georgia,"Times New Roman",serif;letter-spacing:-.035em;margin-bottom:17px}.quiz-introduction p{max-width:610px;color:var(--muted);font-size:13px;line-height:1.85;margin:0}.quiz-setup{padding:28px 33px 31px}.quiz-config{display:grid;grid-template-columns:1.5fr 1fr 1fr;gap:17px;margin-bottom:18px}.quiz-config label{min-width:0;font-size:11px;font-weight:600}.quiz-config label>span{display:block;margin-bottom:8px}.quiz-config select{width:100%;font-size:12px;font-weight:400;min-width:0}.quiz-setup>.small{font-size:11px;line-height:1.85;margin-bottom:22px}.last-result{margin-top:22px;padding:23px 27px}.last-result .eyebrow{font-size:9px;margin-bottom:9px}.last-result h3{margin:0;font-size:19px}.quiz-top{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:-9px -8px 23px;flex-wrap:wrap}.quiz-top .btn{font-size:11px}.quiz-layout{display:grid;grid-template-columns:minmax(0,1fr) 244px;gap:22px;align-items:start}.quiz-layout>*{min-width:0}.quiz-question{padding:29px;min-width:0}.quiz-question>.eyebrow{font-size:9px;margin-bottom:21px}.quiz-question fieldset{border:0;padding:0;margin:0;min-width:0}.quiz-question legend{padding:0;margin-bottom:22px;width:100%}.quiz-question legend.prose{font-size:calc(var(--reading-size) + 2px);line-height:1.8}.quiz-question .prose{max-width:100%;overflow-x:auto;overflow-y:hidden}.options{display:grid;gap:12px;margin:0 0 6px}.option{display:flex;align-items:center;gap:12px;min-width:0;min-height:68px;padding:16px 17px;border:1px solid var(--line);border-radius:10px;cursor:pointer;background:var(--card)}.option:hover{background:var(--light);border-color:#a1b8a0}.option.selected{background:var(--light);border-color:var(--teal);box-shadow:inset 3px 0 var(--teal)}.option.correct{border-color:var(--teal)}.option input{margin:0;flex-shrink:0}.option .letter{display:flex;align-items:center;justify-content:center;min-width:24px;height:24px;color:var(--muted);font-size:11px;font-weight:600}.option.selected .letter{color:var(--teal)}.option .prose{flex:1;min-width:0;font-size:var(--reading-size)}.option .prose p:last-child{margin-bottom:0}.quiz-question .callout{display:block}.quiz-question .callout b{font-size:13px}.quiz-question .callout .prose{font-size:var(--reading-size);margin-top:9px}.quiz-question .actions{margin-top:20px}.quiz-actions{display:flex;align-items:center;justify-content:space-between;gap:11px;margin-top:21px;flex-wrap:wrap}.quiz-actions+.card{margin-top:21px}.quiz-map{position:sticky;top:22px;padding:22px 18px;border-radius:13px}.quiz-map h3{font-size:14px;letter-spacing:-.02em;margin:0 0 9px}.quiz-map>.small{font-size:10px;line-height:1.85;margin-bottom:0}.number-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:7px;margin:18px 0 20px;padding:3px;max-height:min(52vh,480px);overflow-y:auto;scrollbar-gutter:stable}.qnum{min-width:0;min-height:44px;padding:0;border:1px solid var(--line);border-radius:7px;background:var(--card);color:var(--muted);font-size:11px}.qnum.answered{background:var(--light);border-color:#9bb99b;color:var(--teal)}.qnum.current{background:var(--teal);color:#fff;border-color:var(--teal);font-weight:650}.quiz-map .btn{width:100%;font-size:11px;margin-bottom:15px}.score{font:62px/1.1 Georgia,"Times New Roman",serif;color:var(--teal);letter-spacing:-.06em}.score small{font:17px/1.4 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;color:var(--muted);letter-spacing:0}.review-item{margin:14px 0}.review-item summary{display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap}.review-item summary b{font-size:11px}.review-item .prose{padding:22px 25px 10px}.review-item .prose .callout{padding:18px;display:block}.review-item .btn{margin:0 12px 14px}.correct{color:var(--teal)}.wrong{color:var(--danger)}
/* Progress and practical settings. */
.progress-stats{gap:15px;margin:0 0 35px}.progress-stats .stat{border:1px solid var(--line);border-radius:13px;padding:23px 25px;background:var(--card);display:grid;grid-template-columns:1fr auto;align-items:start}.progress-stats .stat>.icon{grid-column:2;grid-row:1 / 3;color:var(--teal);width:23px;height:23px;margin-top:3px}.progress-stats .stat b{display:block;font-size:36px}.progress-stats .stat b small{font:12px/1.3 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;color:var(--muted);letter-spacing:0}.progress-stats .stat>span{display:block;margin-top:9px;font-size:11px}.progress-chapter{display:flex;align-items:flex-start;gap:18px;padding:23px;color:var(--ink);border-radius:13px}.progress-chapter:hover{border-color:#9fb69f}.progress-chapter>div{min-width:0;flex:1}.progress-chapter-no{font:28px/1.1 Georgia,"Times New Roman",serif;color:#94a68e;letter-spacing:-.05em;padding-top:1px;min-width:29px}.progress-chapter h3{font-size:15px;line-height:1.45;margin-bottom:16px;letter-spacing:-.025em}.progress-chapter .progress-fill{height:4px;margin:0 0 11px}.progress-chapter-meta{display:flex;align-items:center;justify-content:space-between;gap:10px;flex-wrap:wrap;color:var(--muted);font-size:9px}.progress-chapter-meta small{font-size:10px}.progress-chapter-meta>span{display:flex;gap:5px;align-items:center}.progress-chapter-meta .icon{width:13px;height:13px;color:var(--teal)}.history-item{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap;padding:18px 23px;border-radius:12px;margin:11px 0}.history-item>a{display:flex;align-items:center;gap:22px;flex:1;min-width:0;color:var(--ink)}.history-icon{display:flex;align-items:center;justify-content:center;flex-shrink:0;width:43px;height:43px;background:var(--light);color:var(--teal);border-radius:10px}.history-icon .icon{width:21px;height:21px}.history-item b{font:28px/1.2 Georgia,"Times New Roman",serif;letter-spacing:-.04em;color:var(--teal);white-space:nowrap}.history-item b small{font:11px/1.4 -apple-system,BlinkMacSystemFont,"Segoe UI",Arial,sans-serif;letter-spacing:0;color:var(--muted)}.history-item>a>span:not(.history-icon){font-size:11px;color:var(--ink)}.history-item>a>span small{display:block;margin-top:5px;font-size:10px;color:var(--muted)}.history-item>a>.icon{width:17px;height:17px;margin-left:auto;color:var(--muted)}.history-item>.btn{font-size:10px}.settings-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:21px}.settings-card{padding:28px 29px}.settings-icon{display:flex;align-items:center;justify-content:center;width:43px;height:43px;border-radius:11px;background:var(--light);color:var(--teal);margin-bottom:20px}.settings-icon .icon{width:23px;height:23px}.settings-card h2{font-size:23px;margin-bottom:14px}.settings-card>p{font-size:12px;line-height:1.9}.setting{display:flex;align-items:center;justify-content:space-between;gap:16px;border-bottom:1px solid var(--line);padding:18px 0;min-height:78px}.setting span{min-width:0}.setting b{display:block;font-size:12px;font-weight:600}.setting small{display:block;color:var(--muted);font-size:10px;line-height:1.7;margin-top:4px}.setting-size select{font-size:12px;min-height:45px;padding:9px 12px;width:90px;flex-shrink:0}.setting.check{font-size:12px}.reading-sample{border:1px solid var(--line);border-radius:10px;padding:18px 19px;background:var(--paper);margin-top:22px}.reading-sample .eyebrow{font-size:8px;margin-bottom:10px;color:var(--muted)}.reading-sample .prose{margin:0;line-height:1.8}.backup-actions{display:grid;gap:10px;margin:23px 0}.backup-actions .btn{justify-content:flex-start}.backup-actions+p{font-size:10px!important;line-height:1.9}.about-card{grid-column:1 / -1;display:grid;grid-template-columns:.65fr 1.35fr;gap:35px;margin-top:1px}.about-card h2{font:36px/1.2 Georgia,"Times New Roman",serif;letter-spacing:-.04em;margin-bottom:17px}.about-card>.eyebrow{font-size:9px}.about-card p{font-size:12px;line-height:1.9}.about-card p:last-child{margin-bottom:0;font-size:10px}.version-tag{display:inline-block;font-size:10px;padding:6px 10px;border:1px solid var(--line);border-radius:5px;color:var(--muted)}#toast{position:fixed;left:50%;bottom:28px;transform:translate(-50%,15px);max-width:calc(100vw - 36px);padding:13px 20px;border:1px solid #6f9279;border-radius:10px;background:#153f33;color:#fff;box-shadow:0 8px 25px #00150b26;font-size:12px;line-height:1.7;z-index:100;opacity:0;pointer-events:none;transition:opacity .15s,transform .15s}#toast.show{opacity:1;transform:translate(-50%,0)}body.dark .btn{color:#132c21}body.dark .btn.secondary,body.dark .btn.ghost{color:var(--ink)}body.dark .btn.danger{color:var(--danger)}body.dark .qnum.current{color:#132c21}body.dark .journey-mark{background:#403c26;color:#e0c780}body.dark .chapter-no,body.dark .progress-chapter-no{color:#8bac8f}body.dark .sidebar{background:#0b2018}body.dark .quiz-hero-icon{border-color:var(--line)}.focusmode .sidebar{display:none}.focusmode .shell{margin-left:0}.focusmode main{max-width:1000px}
@media(max-width:1180px){.sidebar{width:228px;padding-left:17px;padding-right:17px}.shell{margin-left:228px}.sidebar .brand{gap:10px;font-size:23px}.sidebar .brand img{width:44px;height:44px}.sidebar .brand small{font-size:8px}.topbar{padding-left:31px;padding-right:31px}main,#main{padding:36px 31px 45px}.footer{padding-left:31px;padding-right:31px}.home-hero{gap:30px;grid-template-columns:1.2fr 1fr}.hero-copy h1{font-size:57px}.hero-copy>p{font-size:13px}.journey-card{padding:24px 22px}.journey-card h2{font-size:27px}.journey-numbers{gap:8px}.journey-numbers>div+div{padding-left:9px}.journey-numbers b{font-size:22px}.journey-numbers span{font-size:8px}.study-action{padding:17px;gap:12px}.study-action .action-icon{width:37px;height:37px}.study-action p{font-size:10px}.resume-card{padding:25px}.resume-card h2{font-size:27px}.resume-bottom{gap:9px}.resume-bottom>span{font-size:11px}.resume-bottom small{font-size:8px}.quiz-layout{grid-template-columns:minmax(0,1fr) 225px;gap:18px}.quiz-question{padding:24px}.quiz-map{padding:21px 14px}.chapter-card{padding:22px 20px;gap:17px}.chapter-info h3{font-size:16px}.settings-card{padding:25px}.collection-stats .stat{gap:9px;padding-left:22px}.collection-stats .stat span{font-size:10px}}
@media(max-width:1000px){.topbar-tools>.offline{display:none}.home-hero{gap:23px;grid-template-columns:1.15fr 1fr}.hero-copy h1{font-size:49px}.journey-card{padding:22px 19px}.journey-card h2{font-size:25px}.journey-numbers{gap:6px}.journey-numbers>div+div{padding-left:7px}.journey-numbers b{font-size:21px}.journey-numbers small{font-size:8px}.journey-numbers span{font-size:8px;white-space:normal}.study-grid{grid-template-columns:1fr}.study-actions{grid-template-columns:repeat(3,minmax(0,1fr));grid-template-rows:auto;gap:11px}.study-action{align-items:flex-start;flex-wrap:wrap;gap:12px;padding:18px 15px}.study-action>.action-icon{width:37px;height:37px}.study-action>div{flex-basis:100%;order:2}.study-action>.icon{margin-left:auto;width:17px;height:17px}.study-action h3{font-size:15px}.study-action p{font-size:10px}.study-action .eyebrow{font-size:7px}.resume-card{min-height:294px}.quiz-layout{grid-template-columns:minmax(0,1fr)}.quiz-map{position:static;padding:23px}.number-grid{grid-template-columns:repeat(8,minmax(0,1fr));max-height:290px;gap:9px}.quiz-map .btn{width:auto}.quiz-question{padding:29px}.progress-stats .stat{padding:21px 18px}.progress-stats .stat b{font-size:32px}.progress-stats .stat>.icon{width:20px;height:20px}.settings-grid{gap:16px}.about-card{grid-template-columns:.7fr 1.3fr;gap:25px}.filters{grid-template-columns:1fr 1fr}.filter-search{grid-column:1 / -1;grid-row:2}.problem-link{gap:17px;padding:23px}.problem-end{display:none}.problem-meta{align-items:flex-start}.problem-meta small{font-size:9px}.problem-meta .tag{font-size:8px}.reader{padding:32px}}
@media(max-width:850px){.sidebar{display:none}.shell{margin-left:0}.topbar{min-height:76px;padding:14px 26px}.mobile-brand{display:flex;font-size:25px;color:var(--ink)}.mobile-brand img{width:41px;height:41px;border-radius:10px}.mobile-brand b{color:var(--teal);font-size:11px}.topbar .breadcrumb{display:none}.header-institute img{width:42px;height:42px}.header-institute{font-size:8px;gap:10px}.header-institute b{font-size:10px}.topbar-tools{gap:0}main,#main{padding:34px 26px 42px;min-height:calc(100vh - 220px)}.home-hero{grid-template-columns:1.25fr 1fr;gap:35px}.hero-copy h1{font-size:58px}.journey-card h2{font-size:28px}.journey-card{padding:25px}.journey-numbers b{font-size:23px}.journey-numbers span{font-size:9px}.journey-numbers small{font-size:9px}.study-grid{grid-template-columns:1.08fr 1fr}.study-actions{display:grid;grid-template-columns:1fr;grid-template-rows:repeat(3,1fr);gap:10px}.study-action{flex-wrap:nowrap;align-items:center;padding:17px}.study-action>div{flex-basis:auto;order:0}.study-action h3{font-size:15px}.study-action .eyebrow{font-size:7px}.study-action .action-icon{width:36px;height:36px}.study-action p{font-size:9px}.study-action>.icon{width:16px;height:16px}.resume-card h2{font-size:28px}.resume-card>p{font-size:10px}.resume-bottom{flex-wrap:wrap}.resume-bottom small{font-size:9px}.footer{padding:22px 26px 108px}.bottom-nav{position:fixed;inset:auto 0 0;z-index:40;display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:2px;padding:7px 8px calc(8px + env(safe-area-inset-bottom,0px));border-top:1px solid var(--line);background:var(--card);box-shadow:0 -5px 20px #153f3305}.bottom-nav a{min-height:51px;min-width:0;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:5px;color:var(--muted);border-radius:9px;padding:5px 0;font-size:9px}.bottom-nav a .icon{width:21px;height:21px;stroke-width:1.6}.bottom-nav a small{font-size:9px;line-height:1.4}.bottom-nav a.active{background:var(--light);color:var(--teal);font-weight:600}.bottom-nav a.active .icon{stroke-width:1.9}#toast{bottom:91px}.focusmode .bottom-nav{display:none}.focusmode .footer{padding-bottom:24px}.focusmode #toast{bottom:25px}}
@media(max-width:650px){h1{font-size:35px}h2{font-size:23px}.intro{margin-bottom:26px}.intro .eyebrow{font-size:9px;margin-bottom:12px}.intro h1{line-height:1.17;margin-bottom:16px}.intro p{font-size:12px;line-height:1.85}.topbar{min-height:72px;padding:13px 20px}.mobile-brand{font-size:24px;gap:9px}.mobile-brand img{width:38px;height:38px}.header-institute{font-size:7px;gap:8px}.header-institute b{font-size:9px}.header-institute img{width:38px;height:38px}main,#main{padding:28px 20px 35px}.home-hero{grid-template-columns:1fr;gap:25px}.hero-copy{padding:3px 0 0}.hero-copy .eyebrow{font-size:8px;margin-bottom:19px}.hero-copy h1{font-size:57px;line-height:1.04;margin-bottom:21px;letter-spacing:-.065em}.hero-copy>p{max-width:440px;font-size:13px;line-height:1.85;margin-bottom:18px}.hero-credit{font-size:9px}.journey-card{padding:22px 23px;border-radius:14px;display:grid;grid-template-columns:1fr auto;gap:0 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