:root{color-scheme:light;--ink: #17201f;--muted: #65736f;--line: #d7e2de;--panel: #ffffff;--bg: #f4f7f6;--blue: #0f766e;--blue-soft: #dff5f1;--green: #15803d;--green-soft: #e8f7ed;--red: #be123c;--red-soft: #fde8ee;--gold: #b45309;--gold-soft: #fff1d6;--shadow: 0 20px 54px rgba(21, 32, 40, .1);--radius-sm: 4px;--radius-md: 8px;--radius-lg: 12px;--study-canvas: oklch(96.8% .008 165);--study-paper: oklch(99.4% .004 90);--study-ink: oklch(27% .025 175);--study-muted: oklch(49% .025 175);--study-rule: oklch(87% .018 165);--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "PingFang TC", "Noto Sans CJK SC", "Noto Sans CJK TC", "Microsoft YaHei", "Microsoft JhengHei", Arial, sans-serif;font-family:var(--font-sans)}*{box-sizing:border-box}body{min-height:100vh;margin:0;color:var(--ink);background:linear-gradient(180deg,#dff5f1e0,#f4f7f600 360px),var(--bg);font-family:var(--font-sans);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale}button,input,select,textarea{font:inherit}button{display:inline-flex;min-height:42px;align-items:center;justify-content:center;gap:8px;border:1px solid transparent;border-radius:6px;padding:0 15px;color:#fff;background:var(--blue);font-weight:750;cursor:pointer;touch-action:manipulation;transition:transform .15s ease,filter .15s ease,background-color .15s ease,border-color .15s ease,color .15s ease}@media(hover:hover){button:hover{filter:brightness(.97)}}button:active{transform:scale(.98)}button:focus-visible,select:focus-visible,textarea:focus-visible,a:focus-visible,summary:focus-visible,[tabindex="-1"]:focus-visible{outline:3px solid rgba(15,118,110,.24);outline-offset:2px}.skip-link{position:fixed;z-index:100;top:10px;left:10px;transform:translateY(-160%);border-radius:var(--radius-sm);padding:10px 14px;color:#fff;background:var(--blue);font-weight:800;text-decoration:none}.skip-link:focus{transform:translateY(0)}.site-header{display:flex;width:min(1180px,calc(100% - 32px));min-height:70px;align-items:center;justify-content:space-between;gap:18px;margin:0 auto;border-bottom:1px solid rgba(15,118,110,.16)}.site-brand{display:flex;align-items:center;gap:10px;color:var(--ink);text-decoration:none}.site-brand>span{display:grid;min-width:46px;height:30px;place-items:center;border-radius:var(--radius-sm);color:#fff;background:var(--blue);font-size:12px;font-weight:900;letter-spacing:.08em}.site-brand strong{font-size:15px}.mode-navigation{display:flex;gap:4px;border-radius:var(--radius-md);padding:4px;background:#ffffffb8;box-shadow:0 1px 3px #1520281f}.mode-navigation a{display:inline-flex;min-width:92px;min-height:42px;align-items:center;justify-content:center;gap:7px;border-radius:var(--radius-sm);color:var(--muted);font-weight:800;text-decoration:none;transition:transform .15s ease,color .15s ease,background-color .15s ease}.mode-navigation a:active{transform:scale(.96)}.mode-navigation a[aria-current=page]{color:#fff;background:var(--blue)}button:disabled{cursor:not-allowed;opacity:.55}.app-shell{width:min(1180px,calc(100% - 32px));margin:0 auto;padding:28px 0 44px}.topbar{display:flex;align-items:end;justify-content:space-between;gap:20px;margin-bottom:18px}.eyebrow{margin:0 0 6px;color:var(--blue);font-size:14px;font-weight:800}h1,h2,h3,p{margin:0;letter-spacing:0}h1{font-size:40px;line-height:1.12}h2{font-size:24px;line-height:1.52}h3{font-size:15px;line-height:1.4}.stats,.controls,.toolbar,.assistant-panel,.question-panel,.review-panel{border:1px solid var(--line);background:#fffffff0;box-shadow:var(--shadow)}.stats{display:grid;grid-template-columns:repeat(2,minmax(74px,1fr)) 46px;min-width:246px;overflow:hidden;border-radius:8px}.stats div{padding:12px 14px;border-right:1px solid var(--line)}.stats span,.review-panel strong{display:block;font-size:24px;font-weight:850;font-variant-numeric:tabular-nums}.stats small,.review-panel span,.muted{color:var(--muted);font-size:13px}.icon-button{width:46px;min-height:58px;padding:0;border:0;color:var(--blue);background:transparent}.controls{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px;align-items:end;padding:16px;border-radius:8px}label{display:grid;gap:7px;color:var(--muted);font-size:13px;font-weight:800}select,textarea{width:100%;border:1px solid var(--line);border-radius:6px;color:var(--ink);background:#fff}select{height:42px;padding:0 12px}textarea{resize:vertical;min-height:50px;padding:10px 12px;line-height:1.5}.toolbar{display:flex;flex-wrap:wrap;gap:10px;align-items:center;margin:14px 0 16px;padding:12px;border-radius:8px}.assistant-panel{display:grid;grid-template-columns:minmax(0,1fr) 180px auto;gap:14px;align-items:center;margin-bottom:16px;padding:14px 16px;border-radius:8px}.assistant-title{display:flex;align-items:center;gap:11px}.assistant-title>svg{flex:0 0 auto;color:var(--blue)}.assistant-title strong{display:block;font-size:16px}.assistant-title span{color:var(--muted);font-size:13px}.provider-field{min-width:0}.secondary,.toggle{color:var(--blue);background:#fff;border-color:var(--line)}.toggle{min-width:48px}.toggle.active{color:#fff;border-color:var(--green);background:var(--green)}.question-panel{min-height:430px;border-radius:8px;padding:28px}.question-meta{display:flex;flex-wrap:wrap;gap:8px;margin-bottom:16px}.question-meta span{padding:5px 9px;border-radius:999px;color:var(--muted);background:#f0f4f5;font-size:13px;font-weight:750}.options{display:grid;gap:12px;margin-top:24px}.option{display:grid;grid-template-columns:42px 1fr;justify-content:start;gap:12px;width:100%;min-height:58px;border:1px solid var(--line);border-radius:8px;padding:10px 14px 10px 8px;color:var(--ink);background:#fff;text-align:left;font-weight:650}.option-group{display:grid}.option-group.has-analysis .option{border-radius:8px 8px 0 0}.option-ai-analysis{display:grid;grid-template-columns:max-content minmax(0,1fr);gap:10px;border:1px solid var(--line);border-top:0;border-radius:0 0 8px 8px;padding:11px 14px;color:var(--ink);background:var(--blue-soft);line-height:1.6}.option-ai-analysis strong{color:var(--blue);font-size:13px}.option .letter{display:grid;width:38px;height:38px;place-items:center;border-radius:50%;color:var(--blue);background:var(--blue-soft);font-weight:900}.option.correct{border-color:#15803d5c;background:var(--green-soft)}.option.correct .letter{color:#fff;background:var(--green)}.option.wrong{border-color:#be123c57;background:var(--red-soft)}.option.wrong .letter{color:#fff;background:var(--red)}.actions{display:flex;flex-wrap:wrap;gap:10px;margin-top:20px}.result{margin-top:22px;border-left:4px solid var(--green);border-radius:6px;padding:16px;background:#f9fbfa;line-height:1.7}.result.is-wrong{border-left-color:var(--red)}.result>strong{display:block;margin-bottom:6px}.question-study-link{display:flex;width:min(100%,360px);min-height:52px;align-items:center;gap:10px;margin-top:16px;text-align:left}.question-study-link>span{display:grid;gap:1px}.question-study-link small{color:#ffffffd1;font-size:11px;font-weight:700}.review-time{margin-top:8px;color:var(--blue);font-weight:750}.ai-status,.ai-error{display:flex;align-items:center;gap:8px;margin-top:16px;border-radius:6px;padding:12px 14px;font-weight:750}.ai-status{color:var(--blue);background:var(--blue-soft)}.ai-error{color:var(--gold);background:var(--gold-soft)}.ai-content{display:grid;gap:16px;margin-top:18px;border-top:1px solid var(--line);padding-top:18px}.wrong-summary{display:grid;grid-column:1 / -1;gap:16px;border-top:1px solid var(--line);padding-top:16px}.ai-head{display:flex;justify-content:space-between;gap:12px}.ai-head strong{display:block;font-size:18px}.ai-head span{color:var(--muted);font-size:13px}.answer-summary{border-radius:6px;padding:12px 14px;background:var(--blue-soft);font-weight:750}.ai-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.ai-content section,.wrong-summary section{display:grid;gap:8px}.ai-content ul,.wrong-summary ul{display:grid;gap:6px;margin:0;padding-left:20px}.citations,.source-citations{display:grid;gap:8px}.source-citations summary{width:fit-content;cursor:pointer;color:var(--blue);font-weight:750}.citations a{display:grid;gap:3px;border:1px solid var(--line);border-radius:6px;padding:10px 12px;color:inherit;background:#fff;text-decoration:none}.citations a:hover{border-color:#0f766e6b}.question-notes{display:grid;gap:10px}.question-notes div{display:grid;gap:4px;border:1px solid var(--line);border-radius:6px;padding:10px 12px;background:#fff}.question-notes strong{color:var(--blue)}.question-notes span{font-weight:800}.question-notes p{color:var(--muted);line-height:1.6}.chat-panel{display:grid;gap:10px;margin-top:18px;border-top:1px solid var(--line);padding-top:18px}.chat-messages{display:grid;gap:8px}.chat-message{width:fit-content;max-width:min(720px,100%);border-radius:8px;padding:9px 11px;line-height:1.6}.chat-message.user{justify-self:end;color:#fff;background:var(--blue)}.chat-message.assistant{justify-self:start;background:#eef4f5}.chat-error{color:var(--red);font-weight:750}.chat-input{display:grid;grid-template-columns:1fr auto;gap:10px;align-items:end}.review-panel{display:grid;grid-template-columns:repeat(4,1fr);gap:1px;overflow:hidden;margin-top:16px;border-radius:8px;background:var(--line)}.review-panel div{padding:15px 18px;background:#fff}.empty-state{display:grid;min-height:220px;place-items:center;border:1px solid var(--line);border-radius:8px;color:var(--muted);background:#fff;font-weight:750}.study-app-shell{width:min(1280px,calc(100% - 32px));margin:0 auto;padding:28px 0 56px}.study-status{display:flex;min-height:240px;align-items:center;justify-content:center;gap:10px;color:var(--study-muted);font-weight:800}.study-error{display:grid;grid-template-columns:auto minmax(0,560px);gap:16px;justify-content:center;min-height:340px;align-content:center;color:var(--study-ink)}.study-error>svg{color:var(--gold)}.study-error h1{margin-bottom:10px;font-size:30px}.study-error p{color:var(--study-muted);line-height:1.7}.study-action-link{display:inline-flex;min-height:42px;align-items:center;margin-top:18px;border-radius:var(--radius-sm);padding:0 14px;color:#fff;background:var(--blue);font-weight:800;text-decoration:none}.study-home{display:grid;grid-template-columns:minmax(220px,.72fr) minmax(0,1.6fr);gap:clamp(32px,6vw,88px);align-items:start}.study-home-intro{position:sticky;top:24px;padding-top:18px}.study-home-intro h1{max-width:9em;color:var(--study-ink);font-size:clamp(34px,4.5vw,56px);line-height:1.12;text-wrap:balance}.study-home-intro>p:last-child{max-width:30em;margin-top:20px;color:var(--study-muted);line-height:1.8;text-wrap:pretty}.study-paper-index{border-top:1px solid var(--study-rule)}.study-paper-row{display:grid;grid-template-columns:minmax(160px,.65fr) minmax(0,1fr);gap:24px;border-bottom:1px solid var(--study-rule);padding:28px 0 34px}.study-paper-summary{display:flex;gap:14px;align-items:flex-start}.study-paper-summary>span{color:var(--blue);font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:13px;font-weight:900}.study-paper-summary h2{color:var(--study-ink);font-size:25px}.study-paper-summary p{margin-top:4px;color:var(--study-muted);font-size:13px}.study-paper-row>ol{display:grid;gap:2px;margin:0;padding:0;list-style:none}.study-paper-row li a{display:flex;min-height:44px;align-items:center;justify-content:space-between;gap:18px;border-radius:var(--radius-sm);padding:6px 9px;color:var(--study-ink);font-weight:750;text-decoration:none}.study-paper-row li small{flex:0 0 auto;color:var(--study-muted);font-size:12px;font-weight:700}@media(hover:hover){.mode-navigation a:not([aria-current=page]):hover,.study-paper-row li a:hover,.study-directory a:hover,.study-search-chapter li>a:hover{color:var(--blue);background:var(--blue-soft)}}.study-reader-shell{color:var(--study-ink)}.study-practice-return{display:inline-flex;min-height:42px;align-items:center;gap:6px;margin-bottom:14px;border-radius:var(--radius-sm);padding:8px 12px;color:var(--blue);background:var(--blue-soft);font-size:14px;font-weight:850;text-decoration:none}.study-reader-tools{display:flex;flex-wrap:wrap;gap:12px 18px;align-items:end;justify-content:space-between;margin-bottom:18px}.study-reader-primary-tools{display:flex;gap:10px;align-items:end}.study-reader-primary-tools label{width:min(240px,100%)}.study-reader-primary-tools button{flex:0 0 auto;min-height:42px;white-space:nowrap}.study-continue-link{display:flex;min-height:46px;max-width:min(100%,540px);align-items:center;gap:10px;border-radius:var(--radius-sm);padding:7px 12px;color:var(--blue);background:var(--blue-soft);text-decoration:none}.study-continue-link>span{display:grid;min-width:0;gap:2px}.study-continue-link strong{font-size:13px}.study-continue-link small{overflow:hidden;color:var(--study-muted);font-size:11px;font-weight:750;text-overflow:ellipsis;white-space:nowrap}.study-search{margin-bottom:24px;border:1px solid var(--study-rule);border-radius:var(--radius-md);background:#ffffff94}.study-search form{display:grid;grid-template-columns:minmax(140px,200px) minmax(0,1fr);gap:14px;align-items:center;padding:14px 16px}.study-search form>label{color:var(--study-ink);font-size:13px;font-weight:900}.study-search-input-wrap{display:grid;grid-template-columns:auto minmax(0,1fr) auto;min-height:44px;align-items:center;border:1px solid var(--study-rule);border-radius:var(--radius-sm);padding-left:12px;color:var(--study-muted);background:#fff}.study-search-input-wrap:focus-within{border-color:var(--blue);box-shadow:0 0 0 3px color-mix(in srgb,var(--blue) 18%,transparent)}.study-search-input-wrap input{min-width:0;min-height:42px;border:0;padding:0 10px;color:var(--study-ink);background:transparent;outline:0}.study-search-input-wrap input::-webkit-search-cancel-button{display:none}.study-search-input-wrap button{display:grid;min-width:42px;min-height:42px;place-items:center;border:0;padding:0;color:var(--study-muted);background:transparent}.study-search-feedback{border-top:1px solid var(--study-rule);padding:14px 16px 18px}.study-search-feedback>p,.study-search-empty{color:var(--study-muted);font-weight:750}.study-search-empty{display:flex;align-items:center;justify-content:space-between;gap:14px}.study-search-results{max-height:min(54vh,560px);overflow:auto;overscroll-behavior:contain;scrollbar-width:thin}.study-search-count{margin-bottom:14px;color:var(--study-muted);font-size:12px;font-weight:850}.study-search-paper+.study-search-paper{margin-top:20px;border-top:1px solid var(--study-rule);padding-top:18px}.study-search-paper>h2{color:var(--blue);font-size:13px;font-weight:950;letter-spacing:.05em}.study-search-chapter>h3{margin:12px 0 6px;color:var(--study-ink);font-size:14px}.study-search-chapter ol{display:grid;gap:4px;margin:0;padding:0;list-style:none}.study-search-chapter li>a{display:grid;gap:5px;border-radius:var(--radius-sm);padding:9px 10px;color:var(--study-ink);text-decoration:none}.study-search-result-heading{display:flex;align-items:baseline;justify-content:space-between;gap:12px}.study-search-result-heading strong{font-size:13px}.study-search-result-heading small{flex:0 0 auto;color:var(--blue);font-size:10px;font-weight:900}.study-search-snippet{color:var(--study-muted);font-size:12px;line-height:1.55}.study-search-snippet mark{border-radius:2px;padding:0 2px;color:#412300;color:oklch(29% .07 65);background:#fcd176;font-weight:900}.study-reader-grid{display:grid;grid-template-columns:286px minmax(0,1fr);gap:clamp(26px,4vw,54px);align-items:start}.study-desktop-directory{position:sticky;top:20px;max-height:calc(100vh - 40px);overflow:auto;overscroll-behavior:contain;border-radius:var(--radius-md);padding:18px 12px 22px;background:#e1ede7;scrollbar-width:thin}.study-directory>p{margin:0 8px 12px;color:var(--study-muted);font-size:12px;font-weight:900;letter-spacing:.08em}.study-directory ol{display:grid;gap:3px;margin:0;padding:0;list-style:none}.study-directory li>a{display:flex;min-height:40px;align-items:center;justify-content:space-between;gap:10px;border-radius:var(--radius-sm);padding:7px 8px;color:var(--study-muted);font-size:13px;font-weight:750;line-height:1.45;text-decoration:none}.study-directory li>a small{flex:0 0 auto;color:var(--blue);font-size:10px;font-weight:900}.study-directory .is-current-chapter>a{color:var(--study-ink);box-shadow:inset 2px 0 var(--blue)}.study-directory .is-current-chapter>ol{margin:5px 0 8px 14px}.study-directory .is-current-chapter>ol a{position:relative;min-height:36px;padding-left:15px;font-size:12px}.study-directory .is-current-section>a{color:var(--blue);font-weight:850}.study-directory .is-current-section>a:before{position:absolute;left:3px;width:5px;height:5px;border-radius:50%;background:var(--blue);content:""}.study-mobile-directory{display:none}.study-article{width:min(100%,820px);min-width:0;border-radius:var(--radius-lg);padding:clamp(32px,6vw,72px) clamp(24px,6vw,68px) clamp(52px,8vw,92px);background:var(--study-paper);box-shadow:0 1px 3px #1520281f,0 22px 70px #15202814}.study-article>header{margin-bottom:56px;border-bottom:1px solid var(--study-rule);padding-bottom:32px}.study-article>header p{margin-bottom:10px;color:var(--blue);font-size:13px;font-weight:900;letter-spacing:.08em}.study-article>header h1{color:var(--study-ink);font-size:clamp(34px,5vw,48px);line-height:1.2;text-wrap:balance}.study-section{position:relative}.study-section>h2[id]{scroll-margin-top:24px}.study-section+.study-section{margin-top:64px;border-top:1px solid var(--study-rule);padding-top:54px}.study-section>h2{margin-bottom:24px;color:var(--study-ink);font-size:26px;line-height:1.4;text-wrap:balance}.study-section>p,.study-section li,.study-section blockquote,.study-self-test{font-family:inherit;font-size:17px;line-height:1.82}.study-section p{margin:0 0 16px;text-wrap:pretty}.study-section>ul,.study-section>ol,.study-section li>ul,.study-section li>ol,.study-self-test ul,.study-self-test ol{display:grid;gap:7px;margin:12px 0 20px;padding-left:1.45em}.study-section li>p,.study-self-test li>p{margin:0}.study-section h3,.study-section h4,.study-section h5,.study-section h6{margin:30px 0 14px;color:var(--study-ink);font-size:18px;line-height:1.5}.study-section blockquote{margin:22px 0;border-radius:var(--radius-md);padding:16px 20px;color:#264a41;background:var(--blue-soft)}.study-section blockquote p:last-child{margin-bottom:0}.study-section pre{max-width:100%;overflow:auto;border-radius:var(--radius-md);padding:14px 16px;color:var(--study-ink);background:#dfe7e3;white-space:pre-wrap}.study-section a{color:var(--blue);text-underline-offset:3px}.study-self-test{margin:28px 0;border-radius:var(--radius-md);padding:20px;background:#fef2d9;box-shadow:inset 0 0 0 1px #e7cda5}.study-self-test-label{width:fit-content;margin-bottom:14px;border-radius:999px;padding:4px 9px;color:#683c00;background:#f7dba1;font-family:inherit;font-size:12px;font-weight:900}.study-self-test details{margin-top:18px;border-top:1px solid oklch(84% .055 78);padding-top:10px}.study-self-test summary{display:flex;min-height:42px;width:fit-content;align-items:center;color:var(--blue);font-family:inherit;font-size:14px;font-weight:900;cursor:pointer}.study-self-test-answer{margin-top:10px;border-radius:var(--radius-sm);padding:14px 16px 2px;background:#ffffff9e}@media(max-width:820px){.site-header{width:min(100% - 20px,1180px);min-height:64px}.site-brand strong{display:none}.mode-navigation a{min-width:74px}.app-shell{width:min(100% - 20px,1180px);padding-top:18px}.topbar,.controls,.ai-grid,.chat-input{grid-template-columns:1fr}.topbar,.controls{display:grid}.stats{width:100%}.question-panel{padding:20px}h2{font-size:20px}h1{font-size:30px}.toolbar,.actions,.assistant-panel{display:grid;grid-template-columns:1fr}.review-panel{grid-template-columns:1fr}.study-app-shell{width:min(100% - 20px,1280px);padding-top:18px}.study-home{grid-template-columns:1fr;gap:34px}.study-home-intro{position:static}.study-home-intro h1{max-width:12em;font-size:38px}.study-paper-row{grid-template-columns:1fr;gap:16px}.study-reader-tools{display:grid;grid-template-columns:1fr;justify-content:stretch}.study-reader-primary-tools,.study-continue-link{width:100%}.study-reader-primary-tools label{flex:1 1 auto}.study-search form{grid-template-columns:1fr;gap:8px;padding:12px}.study-search-feedback{padding:12px}.study-search-empty{align-items:stretch;flex-direction:column}.study-search-results{max-height:62vh}.study-mobile-directory{display:block;position:sticky;z-index:10;top:8px;margin-bottom:14px;border-radius:var(--radius-md);background:#e1ede7;box-shadow:0 1px 3px #15202824;overscroll-behavior:contain}.study-mobile-directory>summary{display:grid;grid-template-columns:auto 1fr auto;min-height:48px;align-items:center;gap:9px;padding:0 14px;color:var(--study-ink);font-weight:850;cursor:pointer;list-style:none}.study-mobile-directory>summary::-webkit-details-marker{display:none}.study-mobile-directory[open]>summary svg:last-child{transform:scaleY(-1)}.study-mobile-directory .study-directory{max-height:min(68vh,620px);overflow:auto;border-top:1px solid var(--study-rule);padding:16px 12px 20px}.study-desktop-directory{display:none}.study-reader-grid{grid-template-columns:1fr}.study-article{width:100%;border-radius:var(--radius-md);padding:30px 20px 56px}.study-article>header{margin-bottom:42px;padding-bottom:24px}.study-article>header h1{font-size:33px}.study-section+.study-section{margin-top:48px;padding-top:42px}.study-section>h2{font-size:23px}.study-section>p,.study-section li,.study-section blockquote,.study-self-test{font-size:16px;line-height:1.78}.study-self-test{margin-inline:-4px;padding:17px}.study-error{grid-template-columns:1fr;justify-items:start;padding:24px 12px}}@media(prefers-reduced-motion:reduce){button,.mode-navigation a,.study-mobile-directory>summary svg:last-child{transition:none}}
