:root{--accent: #1e3a5f;--accent-2: #3f6ea3;--accent-hover: #152a45;--accent-soft: #e8eef5;--accent-line: #d3e0ee;--bg: #fafbfc;--surface: #f0f3f7;--card: #ffffff;--ink: #161a20;--ink-2: #586170;--ink-3: #9aa2b0;--border: #e3e6ec;--border-2: #cbd1db;--chip: #e6eaf1;--code-bg: #eef1f6;--code-ink: #1e3a5f;--correct: #1f7a4d;--correct-bg: #e6f4ec;--wrong: #c0392b;--wrong-bg: #fbeae7;--warning: #b7791f;--warning-bg: #fbf1de;--font-serif: "Source Serif 4", "Noto Serif SC", Georgia, serif;--font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", "PingFang SC", sans-serif;--font-mono: "JetBrains Mono", "SF Mono", "Fira Code", ui-monospace, monospace;--text-xs: 11px;--text-sm: 13px;--text-base: 15px;--text-md: 16px;--text-lg: 18px;--text-xl: 21px;--text-2xl: 28px;--text-3xl: 40px;--leading-tight: 1.25;--leading-snug: 1.5;--leading-body: 1.6;--leading-read: 1.75;--outline-w: 300px;--content-max: 760px;--content-pad: 40px;--topbar-h: 60px;--radius-sm: 6px;--radius: 8px;--radius-lg: 10px;--shadow-pop: 0 8px 30px rgba(0,0,0,.14)}*{margin:0;padding:0;box-sizing:border-box}body{font-family:var(--font-sans);background:var(--bg);color:var(--ink);font-size:var(--text-base);line-height:var(--leading-read);-webkit-font-smoothing:antialiased}::selection{background:#788ca047}#root{min-height:100vh}.cc-scroll::-webkit-scrollbar{width:10px}.cc-scroll::-webkit-scrollbar-thumb{background:var(--border-2);border-radius:10px;border:3px solid transparent;background-clip:content-box}.cc-scroll::-webkit-scrollbar-thumb:hover{background:var(--ink-3);background-clip:content-box}.brand-line{height:3px;background:linear-gradient(90deg,var(--accent) 0%,var(--accent) 55%,var(--accent-2) 100%);flex:none}.topbar{height:var(--topbar-h);background:var(--card);border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;padding:0 28px;position:sticky;top:0;z-index:100}.topbar-brand{display:flex;align-items:center;gap:16px}.topbar-logo{height:26px;width:auto}.topbar-divider{width:1px;height:26px;background:var(--border-2)}.topbar-title-group{display:flex;flex-direction:column;gap:2px}.topbar-title{font-family:var(--font-serif);font-weight:600;font-size:15.5px;letter-spacing:.2px;color:var(--ink)}.topbar-subtitle{font-size:10.5px;color:var(--ink-3);letter-spacing:.6px;text-transform:uppercase}.topbar-nav{display:flex;align-items:center;gap:4px}.topbar-link{font-size:13.5px;color:var(--ink-2);text-decoration:none;padding:7px 12px;border-radius:var(--radius-sm);transition:all .15s;background:none;border:none;cursor:pointer;font-family:inherit}.topbar-link:hover{background:var(--surface);color:var(--ink)}.topbar-link.active{color:var(--ink);font-weight:500;background:var(--surface)}.topbar-link-external{display:inline-flex;align-items:center;gap:3px}.topbar-link-external:hover{background:none}.external-icon{font-size:10px;opacity:.5}.mobile-menu-btn{display:none;width:36px;height:36px;border:1px solid var(--border);border-radius:var(--radius-sm);background:var(--card);color:var(--ink-2);cursor:pointer;align-items:center;justify-content:center;font-size:18px;flex:none;margin-right:8px}.mobile-menu-btn:hover{background:var(--surface);color:var(--ink)}.topbar-nav-divider{width:1px;height:22px;background:var(--border);margin:0 10px}.topbar-user{display:flex;align-items:center;gap:9px;cursor:pointer;position:relative}.topbar-avatar{width:30px;height:30px;border-radius:50%;background:var(--accent-soft);color:var(--accent);display:flex;align-items:center;justify-content:center;font-size:12px;font-weight:600;border:1px solid var(--accent-line);overflow:hidden}.topbar-avatar img{width:100%;height:100%;object-fit:cover}.topbar-username{font-size:13px;color:var(--ink-2)}.topbar-dropdown{position:absolute;top:calc(100% + 8px);right:0;background:var(--card);border:1px solid var(--border);border-radius:var(--radius);box-shadow:var(--shadow-pop);min-width:180px;padding:8px 0;z-index:200}.topbar-dropdown-item{display:block;padding:8px 16px;font-size:var(--text-sm);color:var(--ink-2);text-decoration:none;cursor:pointer;background:none;border:none;width:100%;text-align:left;font-family:inherit}.topbar-dropdown-item:hover{background:var(--surface);color:var(--ink)}.topbar-dropdown-divider{height:1px;background:var(--border);margin:4px 0}.app-layout{display:flex;height:calc(100vh - 3px - var(--topbar-h));overflow:hidden}.outline{width:var(--outline-w);background:var(--surface);border-right:1px solid var(--border);overflow-y:auto;flex-shrink:0;transition:width .2s;display:flex;flex-direction:column}.outline.collapsed{width:0;overflow:hidden}.outline-toggle{position:fixed;left:var(--outline-w);top:calc(3px + var(--topbar-h));z-index:101;background:var(--card);border:1px solid var(--border);border-left:none;border-radius:0 var(--radius-sm) var(--radius-sm) 0;width:24px;height:36px;cursor:pointer;display:flex;align-items:center;justify-content:center;font-size:var(--text-xs);color:var(--ink-3);transition:left .2s}.outline-toggle.collapsed{left:0}.outline-progress-card{padding:20px 20px 18px;border-bottom:1px solid var(--border)}.outline-progress-header{display:flex;align-items:baseline;justify-content:space-between;margin-bottom:10px}.outline-progress-label{font-size:11px;letter-spacing:1px;text-transform:uppercase;color:var(--ink-3);font-weight:600}.outline-progress-count{font-size:12px;color:var(--ink-2)}.outline-progress-count-num{font-family:var(--font-serif);font-size:16px;font-weight:600;color:var(--accent)}.outline-progress-bar{height:6px;background:var(--border);border-radius:6px;overflow:hidden}.outline-progress-fill{height:100%;background:var(--accent);border-radius:6px;transition:width .3s}.outline-progress-meta{margin-top:9px;font-size:11.5px;color:var(--ink-3);display:flex;justify-content:space-between}.outline-section{margin-bottom:0}.outline-section-title{padding:14px 20px 6px;display:flex;align-items:center;gap:7px;font-size:12.5px;font-weight:600;color:var(--ink);letter-spacing:.2px;cursor:pointer;-webkit-user-select:none;user-select:none}.outline-section-title.collapsed-section{color:var(--ink-2)}.outline-section-arrow{color:var(--ink-3);font-size:10px}.outline-lessons{list-style:none}.outline-lesson{display:flex;align-items:center;gap:8px;padding:7px 20px 7px 37px;font-size:13px;color:var(--ink-2);cursor:pointer;border-left:3px solid transparent}.outline-lesson:hover{background:#00000008}.outline-lesson.active{background:var(--accent-soft);border-left-color:var(--accent);color:var(--ink);font-weight:500;padding-left:34px}.outline-lesson.read .outline-lesson-dot{background:var(--accent);border:none}.outline-lesson.unread .outline-lesson-dot{background:transparent;border:1px solid var(--border-2)}.outline-lesson-dot{width:5px;height:5px;border-radius:50%;flex:none}.outline-lesson-title{flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.outline-lesson-tag{font-size:10.5px;color:var(--ink-3);background:var(--chip);padding:1px 7px;border-radius:4px;flex:none}.content-area{flex:1;overflow-y:auto;min-width:0}.content-breadcrumb{position:sticky;top:0;z-index:5;background:var(--bg);border-bottom:1px solid var(--border)}.content-breadcrumb-inner{max-width:var(--content-max);margin:0 auto;padding:13px var(--content-pad);display:flex;align-items:center;justify-content:space-between}.content-breadcrumb-path{font-size:12.5px;color:var(--ink-3);display:flex;align-items:center;gap:7px}.content-breadcrumb-sep{color:var(--border-2)}.content-breadcrumb-current{color:var(--ink-2)}.content-breadcrumb-nav{display:flex;align-items:center;gap:12px}.content-breadcrumb-counter{font-size:12px;color:var(--ink-3)}.content-breadcrumb-counter-num{color:var(--accent);font-weight:600}.content-breadcrumb-btns{display:flex;gap:4px}.content-breadcrumb-btn{width:28px;height:28px;border:1px solid var(--border);background:var(--card);border-radius:7px;color:var(--ink-2);cursor:pointer;font-size:13px;display:flex;align-items:center;justify-content:center;transition:all .15s}.content-breadcrumb-btn:hover:not(:disabled){border-color:var(--accent);color:var(--accent)}.content-breadcrumb-btn:disabled{opacity:.4;cursor:not-allowed}.content-breadcrumb-unread{border:1px solid var(--border);background:var(--card);border-radius:var(--radius-sm);color:var(--ink-3);cursor:pointer;font-size:11px;padding:4px 10px;font-family:inherit;transition:all .15s;white-space:nowrap}.content-breadcrumb-unread:hover{border-color:var(--accent);color:var(--accent)}.content-reading-progress{height:2px;background:var(--border)}.content-reading-progress-fill{height:100%;background:var(--accent);transition:width .3s}.content-article{max-width:var(--content-max);margin:0 auto;padding:40px var(--content-pad) 40px}.lesson-kicker{font-size:12px;letter-spacing:1.5px;text-transform:uppercase;color:var(--accent);font-weight:600;margin-bottom:12px}.lesson-h1{font-family:var(--font-serif);font-weight:700;font-size:32px;line-height:var(--leading-tight);margin:0 0 8px;letter-spacing:-.3px}.lesson-subtitle{font-size:14px;color:var(--ink-2);margin:0 0 32px;line-height:var(--leading-body)}.content-heading{font-family:var(--font-serif);font-weight:600;letter-spacing:-.2px;margin:0}.content-heading[data-level="2"]{font-size:var(--text-xl);margin:28px 0 14px}.content-heading[data-level="3"]{font-size:var(--text-lg);margin:24px 0 12px}.content-heading:first-child{margin-top:0}.content-paragraph{font-size:var(--text-base);line-height:var(--leading-read);margin:0 0 16px;color:var(--ink);text-wrap:pretty}.content-paragraph code,.content-blockquote code,.callout code,.quiz-explanation code{font-family:var(--font-mono);font-size:13px;background:var(--code-bg);padding:1.5px 5px;border-radius:var(--radius-sm);color:var(--code-ink)}.content-paragraph a,.content-blockquote a{color:var(--accent);text-decoration:none;text-underline-offset:2px}.content-paragraph a:hover{color:var(--accent-hover);text-decoration:underline}.content-blockquote{border-left:3px solid var(--border-2);color:var(--ink-2);padding-left:16px;margin:16px 0;font-size:var(--text-base);line-height:var(--leading-body)}.content-hr{border:none;border-top:1px solid var(--border);margin:24px 0}.content-code-block{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);margin:20px 0 28px;overflow:hidden}.content-code-label{padding:8px 16px;border-bottom:1px solid var(--border);font-size:11px;color:var(--ink-3);letter-spacing:.5px;font-family:var(--font-mono)}.content-code{margin:0;padding:14px 16px;overflow-x:auto;font-family:var(--font-mono);font-size:13px;line-height:1.7;color:var(--ink);white-space:pre}.content-table{width:100%;border-collapse:collapse;margin:16px 0;font-size:var(--text-sm);overflow-x:auto;display:block}.content-table thead{background:var(--surface)}.content-table th{border:1px solid var(--border);padding:8px 12px;text-align:left;color:var(--ink-2);font-weight:600}.content-table td{border:1px solid var(--border);padding:8px 12px;color:var(--ink)}.content-table tbody tr:nth-child(2n){background:var(--bg)}.content-details{margin:16px 0;border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}.content-details-summary{padding:10px 16px;font-weight:600;cursor:pointer;background:var(--surface);font-size:var(--text-sm);color:var(--ink);-webkit-user-select:none;user-select:none}.content-details-content{padding:16px}.callout{border-radius:var(--radius);border:1px solid;padding:14px 16px;margin:20px 0;display:flex;align-items:flex-start;gap:10px}.callout-icon{flex:none;width:20px;height:20px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:12px;font-family:var(--font-serif);font-weight:700;color:#fff;margin-top:2px}.callout-body{font-size:var(--text-sm);line-height:var(--leading-body);color:var(--ink);flex:1;min-width:0}.callout-body strong{font-weight:600}.callout.callout-info{background:var(--accent-soft);border-color:var(--accent-line)}.callout.callout-info .callout-icon{background:var(--accent)}.callout.callout-warning{background:var(--warning-bg);border-color:var(--warning)}.callout.callout-warning .callout-icon{background:var(--warning)}.callout.callout-danger{background:var(--wrong-bg);border-color:var(--wrong)}.callout.callout-danger .callout-icon{background:var(--wrong)}.callout.callout-success{background:var(--correct-bg);border-color:var(--correct)}.callout.callout-success .callout-icon{background:var(--correct)}.bottom-nav{border-top:1px solid var(--border);background:var(--surface)}.bottom-nav-inner{max-width:var(--content-max);margin:0 auto;padding:20px var(--content-pad) 32px;display:flex;gap:14px}.bottom-nav-card{flex:1;text-decoration:none;border:1px solid var(--border);border-radius:var(--radius-lg);padding:14px 18px;background:var(--card);display:flex;flex-direction:column;gap:4px;transition:all .15s;cursor:pointer}.bottom-nav-card:hover:not(.disabled){border-color:var(--accent)}.bottom-nav-card.disabled{opacity:.4;cursor:not-allowed}.bottom-nav-card-label{font-size:11.5px;color:var(--ink-3)}.bottom-nav-card-title{font-size:14px;color:var(--ink);font-weight:500}.bottom-nav-card.next{align-items:flex-end;text-align:right}.quiz-question{background:var(--card);border:1px solid var(--border);border-radius:var(--radius-lg);padding:20px;margin-bottom:var(--gap, 16px)}.quiz-question.correct{border-left:3px solid var(--correct)}.quiz-question.wrong{border-left:3px solid var(--wrong)}.quiz-question-number{font-size:12px;color:var(--ink-3);margin-bottom:10px}.quiz-statement{font-size:var(--text-md);line-height:var(--leading-snug);margin-bottom:16px;color:var(--ink)}.quiz-option{display:flex;gap:11px;align-items:flex-start;padding:12px 14px;border:1px solid var(--border);border-radius:var(--radius);cursor:pointer;font-size:14px;line-height:1.5;margin-bottom:8px;transition:all .12s}.quiz-option:hover{border-color:var(--border-2);background:var(--surface)}.quiz-option.selected{border:1.5px solid var(--accent);background:var(--accent-soft)}.quiz-option.selected .quiz-radio{border:5px solid var(--accent);background:#fff}.quiz-radio{flex:none;width:18px;height:18px;border:1.5px solid var(--border-2);border-radius:50%;margin-top:1px;transition:all .12s}.quiz-option-label{flex:1}.quiz-option.correct-answer{background:var(--correct-bg);border-color:var(--correct)}.quiz-option.wrong-answer{background:var(--wrong-bg);border-color:var(--wrong);text-decoration:line-through}.quiz-explanation{margin-top:12px;padding:14px 16px;background:var(--accent-soft);border-left:3px solid var(--accent);border-radius:var(--radius);font-size:var(--text-sm);line-height:var(--leading-body);color:var(--ink)}.quiz-submit-bar{margin-top:24px;display:flex;align-items:center;justify-content:center;gap:16px}.quiz-submit-btn{padding:10px 22px;border:none;border-radius:7px;font-size:14px;font-weight:500;cursor:pointer;font-family:inherit;transition:background .15s}.quiz-submit-btn.disabled{background:var(--border);color:var(--ink-3);cursor:not-allowed}.quiz-submit-btn.enabled{background:var(--accent);color:#fff}.quiz-submit-btn.enabled:hover{background:var(--accent-hover)}.quiz-submit-hint{font-size:var(--text-sm);color:var(--ink-3)}.quiz-score{margin-top:16px;font-size:var(--text-lg);font-weight:600;color:var(--ink)}.login-main{display:flex;align-items:center;justify-content:center;min-height:100vh;background:var(--bg)}.login-box{text-align:center;max-width:400px;padding:48px 32px}.login-logo{height:64px;width:auto;margin-bottom:20px}.login-box h1{font-family:var(--font-serif);font-size:var(--text-2xl);margin-bottom:12px;color:var(--ink);font-weight:700}.login-box p{color:var(--ink-2);margin-bottom:24px;line-height:var(--leading-body)}.btn-primary{display:inline-block;padding:14px 28px;background:var(--accent);color:#fff;border:none;border-radius:var(--radius-sm);font-size:var(--text-base);font-weight:500;cursor:pointer;font-family:inherit;transition:background .15s}.btn-primary:hover{background:var(--accent-hover)}.login-hint{margin-top:20px;font-size:var(--text-sm);color:var(--ink-3)}.login-hint a{color:var(--accent);text-decoration:none}.login-hint a:hover{text-decoration:underline}.loading-text{color:var(--ink-2);font-size:var(--text-sm)}.no-access{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:100vh;text-align:center;gap:16px;padding:32px}.no-access h1{font-family:var(--font-serif);font-size:var(--text-xl);font-weight:700;color:var(--ink);max-width:500px}.no-access p{color:var(--ink-2);max-width:400px;line-height:var(--leading-body)}.no-access-btn{display:inline-block;padding:12px 24px;background:var(--accent);color:#fff;border-radius:var(--radius-sm);text-decoration:none;font-weight:500;font-size:var(--text-base);transition:background .15s}.no-access-btn:hover{background:var(--accent-hover)}.mock-loading{padding:64px 32px;text-align:center;color:var(--ink-2)}.mock-exam-container{max-width:var(--content-max);margin:0 auto;padding:var(--content-pad);min-height:calc(100vh - 3px - var(--topbar-h))}.mock-exam-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:12px}.mock-exam-title{font-family:var(--font-serif);font-size:var(--text-xl);font-weight:700}.mock-exam-meta{font-size:var(--text-sm);color:var(--ink-2)}.mock-progress-bar{height:4px;background:var(--surface);border-radius:2px;overflow:hidden;margin-bottom:4px}.mock-progress-fill{height:100%;background:var(--accent);transition:width .3s}.mock-progress-text{font-size:var(--text-xs);color:var(--ink-3);margin-bottom:24px}.answered-mark{color:var(--accent);margin-left:4px}.mock-result-container{max-width:var(--content-max);margin:0 auto;padding:var(--content-pad)}.mock-result-header{text-align:center;margin:24px 0 32px}.mock-result-score-ring{position:relative;width:120px;height:120px;margin:0 auto 16px}.mock-result-score-text{font-family:var(--font-serif);font-size:var(--text-3xl);font-weight:700;color:var(--ink)}.mock-result-percentage{font-size:var(--text-lg);color:var(--ink-2);margin-top:4px}.mock-result-label{font-size:var(--text-base);font-weight:600;margin-top:12px;display:inline-block;padding:4px 14px;border-radius:var(--radius-sm)}.mock-result-label.passed{color:var(--correct);background:var(--correct-bg)}.mock-result-label.failed{color:var(--warning);background:var(--warning-bg)}.mock-confirm-overlay{position:fixed;top:0;left:0;right:0;bottom:0;background:#0006;display:flex;align-items:center;justify-content:center;z-index:200}.mock-confirm-dialog{background:var(--card);border-radius:var(--radius-lg);padding:24px;max-width:360px;box-shadow:var(--shadow-pop)}.mock-confirm-dialog h3{font-family:var(--font-serif);font-size:var(--text-lg);margin-bottom:8px;color:var(--ink)}.mock-confirm-dialog p{color:var(--ink-2);margin-bottom:16px;font-size:var(--text-sm)}.mock-confirm-buttons{display:flex;gap:12px;justify-content:flex-end}.mock-confirm-cancel{padding:8px 16px;border:1px solid var(--border);border-radius:var(--radius-sm);background:transparent;cursor:pointer;font-size:var(--text-sm);font-family:inherit;color:var(--ink-2)}.mock-confirm-ok{padding:8px 16px;border:none;border-radius:var(--radius-sm);background:var(--accent);color:#fff;cursor:pointer;font-size:var(--text-sm);font-family:inherit}.mock-confirm-ok:hover{background:var(--accent-hover)}.cta-card{background:var(--card);border:1px solid var(--border);border-radius:var(--radius-lg);padding:28px;margin:32px 0;text-align:center}.cta-card h3{font-family:var(--font-serif);font-size:var(--text-lg);margin-bottom:8px;color:var(--ink)}.cta-card p{color:var(--ink-2);margin-bottom:16px;line-height:var(--leading-body)}.cta-btn{display:inline-block;padding:10px 22px;background:var(--accent);color:#fff;border-radius:var(--radius-sm);text-decoration:none;font-weight:500;font-size:var(--text-base);transition:background .15s}.cta-btn:hover{background:var(--accent-hover)}@media (max-width: 768px){.outline{position:fixed;top:calc(3px + var(--topbar-h));left:0;bottom:0;z-index:99;width:var(--outline-w);transform:translate(-100%);transition:transform .25s ease;box-shadow:var(--shadow-pop)}.outline.mobile-open{transform:translate(0)}.outline.collapsed{transform:translate(-100%);width:var(--outline-w)}.outline-toggle{display:none!important}.mobile-menu-btn{display:flex!important}.mobile-overlay{position:fixed;top:calc(3px + var(--topbar-h));left:0;right:0;bottom:0;background:#0000004d;z-index:98;display:none}.mobile-overlay.visible{display:block}.topbar{padding:0 12px}.topbar-subtitle,.topbar-username,.topbar-divider{display:none}.topbar-title{font-size:13px}.topbar-link{padding:7px 6px;font-size:12px}.content-area{width:100%}.content-article{padding:24px 16px}.content-breadcrumb-inner{padding:13px 16px}.bottom-nav-inner{padding:16px 16px 24px;flex-direction:column}.bottom-nav-card.next{align-items:flex-start;text-align:left}.callout{flex-direction:column;gap:10px}.mock-exam-container,.mock-result-container{padding:20px 16px}.quiz-option{min-height:44px;padding:12px 14px}.content-code-block{margin:16px -16px;border-radius:0}.content-code{padding:12px 16px;font-size:12px}.content-table{display:block;overflow-x:auto;-webkit-overflow-scrolling:touch}}@media (min-width: 769px){.mobile-menu-btn,.mobile-overlay{display:none!important}}