:root{--bg:#0e1116;--bg2:#131822;--surface:#171d29;--surface2:#1d2432;--border:#263042;--border2:#33405a;--text:#e7ebf3;--muted:#98a3b8;--faint:#6b7690;--accent:#f89820;--accent-soft:#f8982024;--blue:#6ea8d8;--green:#3fb68b;--green-soft:#3fb68b1f;--red:#e5645c;--red-soft:#e5645c1f;--code-bg:#10151f;--shadow:0 8px 30px #00000059;--tok-comment:#667a94;--tok-keyword:#c792ea;--tok-string:#a5d6a7;--tok-number:#f2b866;--tok-function:#82aaff;--tok-class:#ffcb6b;--tok-punct:#8fa1b8;--tok-op:#89ddff;--tok-anno:#f78c6c}:root[data-theme=light]{--bg:#f5f7fa;--bg2:#eef1f6;--surface:#fff;--surface2:#f6f8fb;--border:#dfe5ee;--border2:#c9d3e2;--text:#1d2534;--muted:#5a6678;--faint:#8b95a8;--accent:#d97e06;--accent-soft:#d97e061f;--blue:#2f6ea5;--green:#1e8e66;--green-soft:#1e8e661a;--red:#c53c34;--red-soft:#c53c3417;--code-bg:#f0f3f8;--shadow:0 8px 30px #18274b14;--tok-comment:#8b95a8;--tok-keyword:#8f3fbf;--tok-string:#2e7d32;--tok-number:#b26a00;--tok-function:#2962ad;--tok-class:#a56802;--tok-punct:#5a6678;--tok-op:#0f7c99;--tok-anno:#c25523}*{box-sizing:border-box}html{-webkit-text-size-adjust:100%}body{background:var(--bg);color:var(--text);margin:0;font-family:-apple-system,BlinkMacSystemFont,Segoe UI,Roboto,Helvetica Neue,Arial,sans-serif;font-size:16px;line-height:1.65}a{color:var(--blue);text-decoration:none}a:hover{text-decoration:underline}code,pre,.opt-letter,.exam-timer,.pal{font-family:ui-monospace,SF Mono,SFMono-Regular,Menlo,Consolas,Liberation Mono,monospace}code{background:var(--code-bg);border:1px solid var(--border);border-radius:5px;padding:.1em .35em;font-size:.88em}pre.codeblock{background:var(--code-bg);border:1px solid var(--border);border-radius:10px;margin:14px 0;padding:14px 16px;font-size:.86rem;line-height:1.6;overflow-x:auto}pre.codeblock code{font-size:inherit;background:0 0;border:none;padding:0}.token.comment{color:var(--tok-comment);font-style:italic}.token.keyword{color:var(--tok-keyword)}.token.string,.token.char{color:var(--tok-string)}.token.number,.token.boolean{color:var(--tok-number)}.token.function{color:var(--tok-function)}.token.class-name{color:var(--tok-class)}.token.punctuation{color:var(--tok-punct)}.token.operator{color:var(--tok-op)}.token.annotation,.token.generics{color:var(--tok-anno)}.token.namespace{opacity:.85}.topbar{z-index:40;background:color-mix(in srgb, var(--bg) 82%, transparent);-webkit-backdrop-filter:blur(10px);backdrop-filter:blur(10px);border-bottom:1px solid var(--border);justify-content:space-between;align-items:center;gap:12px;height:56px;padding:0 18px;display:flex;position:sticky;top:0}.topbar-left,.topbar-right{align-items:center;gap:12px;min-width:0;display:flex}.topbar-left{flex:auto}.topbar-right{flex:none}.brand{color:var(--text);letter-spacing:.01em;white-space:nowrap;align-items:center;gap:9px;min-width:0;font-weight:700;display:flex}.brand-text{text-overflow:ellipsis;overflow:hidden}.brand:hover{text-decoration:none}.brand-cup{font-size:1.25rem}.brand-text em{color:var(--accent);font-style:normal}.iconbtn{border:1px solid var(--border);cursor:pointer;width:34px;height:34px;color:var(--text);background:0 0;border-radius:8px;justify-content:center;align-items:center;font-size:.95rem;display:inline-flex}.iconbtn:hover{border-color:var(--border2);background:var(--surface)}.navtoggle{display:none}.burger,.burger:before,.burger:after{content:"";background:var(--text);border-radius:2px;width:15px;height:2px;display:block;position:relative}.burger:before{position:absolute;top:-5px}.burger:after{position:absolute;top:5px}.global-progress{color:var(--muted);align-items:center;gap:8px;font-size:.8rem;font-weight:600;display:flex}.global-progress-bar{background:var(--surface2);border:1px solid var(--border);border-radius:4px;width:110px;height:6px;overflow:hidden}.global-progress-bar>div{background:linear-gradient(90deg, var(--accent), #ffb95e);border-radius:4px;height:100%;transition:width .3s}.btn{cursor:pointer;white-space:nowrap;border:1px solid #0000;border-radius:9px;justify-content:center;align-items:center;gap:6px;padding:9px 18px;font-size:.92rem;font-weight:650;transition:transform 60ms,background .15s,border-color .15s;display:inline-flex}.btn:active{transform:translateY(1px)}.btn:hover{text-decoration:none}.btn-primary{background:var(--accent);color:#16120a;border-color:color-mix(in srgb, var(--accent) 70%, #000 30%)}.btn-primary:hover{filter:brightness(1.07)}.btn-primary:disabled{opacity:.45;cursor:not-allowed}.btn-ghost{color:var(--text);border-color:var(--border2);background:0 0}.btn-ghost:hover{background:var(--surface)}.btn-ghost.flagged{color:var(--accent);border-color:var(--accent)}.btn-exam{background:var(--accent-soft);color:var(--accent);border-color:color-mix(in srgb, var(--accent) 45%, transparent)}.btn-exam:hover{background:color-mix(in srgb, var(--accent) 22%, transparent)}.btn-sm{padding:6px 14px;font-size:.85rem}.linklike{color:var(--blue);cursor:pointer;font:inherit;background:0 0;border:none;padding:0}.linklike:hover{text-decoration:underline}.layout{grid-template-columns:304px minmax(0,1fr);max-width:1280px;margin:0 auto;display:grid}.content{min-width:0;padding:34px 42px 80px}.sidebar{border-right:1px solid var(--border);scrollbar-width:thin;height:calc(100vh - 56px);padding:22px 14px 40px;position:sticky;top:56px;overflow-y:auto}.nav-section{margin-bottom:18px}.nav-section-head{text-transform:uppercase;letter-spacing:.05em;color:var(--muted);align-items:baseline;gap:8px;padding:4px 10px;font-size:.82rem;font-weight:700;display:flex}.nav-section-num{color:var(--accent);font-family:ui-monospace,Menlo,monospace}.nav-section-title{flex:1;min-width:0}.nav-section-count{color:var(--faint);font-family:ui-monospace,Menlo,monospace;font-size:.72rem}.nav-section ul{margin:4px 0 0;padding:0;list-style:none}.nav-item{color:var(--muted);border-radius:8px;align-items:center;gap:8px;padding:6px 10px;font-size:.88rem;line-height:1.35;display:flex}.nav-item:hover{background:var(--surface);color:var(--text);text-decoration:none}.nav-item.active{background:var(--accent-soft);color:var(--text);font-weight:600}.nav-item-id{color:var(--faint);min-width:26px;font-family:ui-monospace,Menlo,monospace;font-size:.72rem}.nav-item-title{min-width:0}.dot{background:var(--border2);border-radius:50%;flex:none;width:7px;height:7px}.dot-progress{background:var(--accent)}.dot-done{background:var(--green)}.scrim{display:none}.hero{max-width:780px;padding:26px 0 8px}.hero-kicker{color:var(--accent);text-transform:uppercase;letter-spacing:.09em;margin:0 0 10px;font-size:.76rem;font-weight:700}.hero h1{letter-spacing:-.015em;margin:0 0 14px;font-size:clamp(1.7rem,3.4vw,2.6rem);line-height:1.15}.accent{color:var(--accent)}.hero-sub{color:var(--muted);margin:0 0 22px;font-size:1.02rem}.hero-actions{flex-wrap:wrap;gap:12px;display:flex}.hero-best{color:var(--muted);margin-top:16px;font-size:.9rem}.section-grid{grid-template-columns:repeat(auto-fill,minmax(270px,1fr));gap:14px;margin-top:34px;display:grid}.section-card{background:var(--surface);border:1px solid var(--border);color:var(--text);border-radius:14px;padding:16px 18px 14px;transition:border-color .15s,transform .12s;display:block}.section-card:hover{border-color:var(--accent);text-decoration:none;transform:translateY(-2px)}.section-card-top{justify-content:space-between;align-items:baseline;margin-bottom:6px;display:flex}.section-card-num{color:var(--accent);font-family:ui-monospace,Menlo,monospace;font-size:.95rem;font-weight:700}.section-card-pct{color:var(--faint);font-family:ui-monospace,Menlo,monospace;font-size:.75rem}.section-card h3{margin:0 0 6px;font-size:1.02rem;line-height:1.3}.section-card p{color:var(--muted);margin:0 0 10px;font-size:.85rem;line-height:1.5}.section-card-meta{color:var(--faint);margin-bottom:10px;font-size:.75rem}.section-card-bar{background:var(--surface2);border-radius:3px;height:4px;overflow:hidden}.section-card-bar>div{background:var(--green);border-radius:3px;height:100%}.home-foot{color:var(--faint);margin-top:34px;font-size:.85rem}.crumbs{color:var(--faint);gap:8px;margin-bottom:10px;font-size:.82rem;display:flex}.subtitle{letter-spacing:-.01em;margin:0 0 20px;font-size:clamp(1.45rem,2.6vw,2rem);line-height:1.2}.subtitle-id{color:var(--accent);margin-right:6px;font-family:ui-monospace,Menlo,monospace;font-size:.8em}.lesson{max-width:780px}.lesson h2{letter-spacing:-.01em;margin:34px 0 10px;padding-top:10px;font-size:1.32rem}.lesson h3{margin:26px 0 8px;font-size:1.08rem}.lesson p,.lesson li{color:color-mix(in srgb, var(--text) 88%, var(--muted))}.lesson ul,.lesson ol{padding-left:24px}.lesson li{margin:4px 0}.lesson table{border-collapse:collapse;margin:14px 0;font-size:.88rem;display:block;overflow-x:auto}.lesson th,.lesson td{border:1px solid var(--border);text-align:left;padding:7px 12px}.lesson th{background:var(--surface);font-weight:650}.lesson blockquote{border-left:3px solid var(--accent);background:var(--accent-soft);border-radius:0 10px 10px 0;margin:16px 0;padding:12px 16px;font-size:.93rem}.lesson blockquote p{margin:0}.lesson blockquote+blockquote{margin-top:10px}.lesson hr{border:none;border-top:1px solid var(--border);margin:28px 0}.quiz-divider{border-top:2px solid var(--border);max-width:780px;margin-top:44px;padding-top:26px}.quiz-divider h2{margin:0 0 4px;font-size:1.3rem}.quiz-divider p{color:var(--muted);margin:0;font-size:.9rem}.quiz{max-width:780px;margin-top:18px}.quiz-progress{color:var(--muted);align-items:center;gap:10px;margin-bottom:14px;font-size:.8rem;font-weight:600;display:flex}.quiz-progress-bar{background:var(--surface2);border:1px solid var(--border);border-radius:4px;flex:1;height:6px;overflow:hidden}.quiz-progress-bar>div{background:var(--green);height:100%;transition:width .3s}.qcard{background:var(--surface);border:1px solid var(--border);box-shadow:var(--shadow);border-radius:14px;margin-bottom:18px;padding:18px 20px}.qcard-right{border-color:color-mix(in srgb, var(--green) 55%, var(--border))}.qcard-wrong{border-color:color-mix(in srgb, var(--red) 55%, var(--border))}.qcard-head{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:10px;margin-bottom:8px;display:flex}.qcard-num{text-transform:uppercase;letter-spacing:.06em;color:var(--accent);font-size:.8rem;font-weight:700}.qcard-pick{color:var(--muted);border:1px solid var(--border2);border-radius:20px;padding:2px 9px;font-size:.75rem;font-weight:600}.qcard-text{font-size:.95rem}.qcard-text p{margin:8px 0}.qcard-text pre.codeblock{margin:10px 0}.qcard-options{flex-direction:column;gap:8px;margin:14px 0 4px;display:flex}.opt{text-align:left;background:var(--surface2);width:100%;color:var(--text);border:1px solid var(--border);cursor:pointer;border-radius:10px;align-items:flex-start;gap:11px;padding:10px 12px;font-size:.9rem;line-height:1.5;transition:border-color .12s,background .12s;display:flex}.opt:hover{border-color:var(--border2)}.opt-static{cursor:default}.opt-selected{border-color:var(--blue);background:color-mix(in srgb, var(--blue) 12%, var(--surface2))}.opt-correct{border-color:var(--green)!important;background:var(--green-soft)!important}.opt-incorrect{border-color:var(--red)!important;background:var(--red-soft)!important}.opt-letter{background:var(--bg2);border:1px solid var(--border2);width:24px;height:24px;color:var(--muted);border-radius:7px;flex:none;justify-content:center;align-items:center;margin-top:1px;font-size:.75rem;font-weight:700;display:inline-flex}.opt-selected .opt-letter{background:var(--blue);border-color:var(--blue);color:#fff}.opt-correct .opt-letter{background:var(--green);border-color:var(--green);color:#fff}.opt-incorrect .opt-letter{background:var(--red);border-color:var(--red);color:#fff}.opt-text{overflow-wrap:anywhere;flex:1;min-width:0}.opt-text code{font-size:.84em}.opt-mark{flex:none;margin-left:4px;font-weight:800}.opt-correct .opt-mark{color:var(--green)}.opt-incorrect .opt-mark{color:var(--red)}.qcard-actions{align-items:center;gap:12px;margin-top:12px;display:flex}.verdict{text-transform:uppercase;letter-spacing:.04em;font-size:.9rem;font-weight:800}.verdict-right{color:var(--green)}.verdict-wrong{color:var(--red)}.explain{border-top:1px dashed var(--border2);margin-top:14px;padding-top:12px;font-size:.9rem}.explain-label{text-transform:uppercase;letter-spacing:.08em;color:var(--blue);margin-bottom:4px;font-size:.72rem;font-weight:800}.explain p{margin:6px 0}.pager{justify-content:space-between;gap:14px;max-width:780px;margin-top:40px;display:flex}.pager-link{border:1px solid var(--border);color:var(--muted);border-radius:12px;flex-direction:column;gap:2px;max-width:48%;padding:12px 16px;font-size:.78rem;display:flex}.pager-link strong{color:var(--text);font-size:.9rem;line-height:1.3}.pager-link:hover{border-color:var(--accent);text-decoration:none}.pager-link.next{text-align:right;margin-left:auto}.notfound{padding:60px 0}.exam-main{max-width:1080px;margin:0 auto;padding:26px 24px 80px}.exam-intro{max-width:640px;margin:40px auto}.exam-exit{color:var(--muted);font-size:.85rem}.exam-intro h1{letter-spacing:-.01em;margin:14px 0 10px}.exam-intro p{color:var(--muted)}.exam-choices{grid-template-columns:1fr 1fr;gap:14px;margin-top:26px;display:grid}.exam-choice{background:var(--surface);border:1px solid var(--border);cursor:pointer;color:var(--text);text-align:left;border-radius:14px;flex-direction:column;gap:6px;padding:20px 18px;font-size:1rem;transition:border-color .15s,transform .1s;display:flex}.exam-choice:hover{border-color:var(--accent);transform:translateY(-2px)}.exam-choice strong{font-size:1.05rem}.exam-choice span{color:var(--muted);font-size:.85rem}.exam-bar{z-index:30;background:var(--surface);border:1px solid var(--border);border-radius:12px;align-items:center;gap:14px;margin-bottom:20px;padding:10px 14px;display:flex;position:sticky;top:56px}.exam-count{color:var(--muted);margin-left:auto;font-size:.85rem;font-weight:600}.exam-timer{color:var(--text);text-align:right;min-width:76px;font-size:.95rem;font-weight:700}.exam-timer-low{color:var(--red)}.exam-body{grid-template-columns:minmax(0,1fr) 216px;align-items:start;gap:20px;display:grid}.exam-nav{justify-content:space-between;gap:10px;margin-top:6px;display:flex}.exam-palette{background:var(--surface);border:1px solid var(--border);border-radius:12px;grid-template-columns:repeat(auto-fill,minmax(34px,1fr));gap:6px;padding:12px;display:grid;position:sticky;top:122px}.pal{border:1px solid var(--border2);background:var(--surface2);height:32px;color:var(--muted);cursor:pointer;border-radius:8px;font-size:.75rem;font-weight:700}.pal-answered{background:color-mix(in srgb, var(--blue) 22%, var(--surface2));color:var(--text);border-color:var(--blue)}.pal-flagged{box-shadow:inset 0 0 0 2px var(--accent)}.pal-current{outline:2px solid var(--accent);outline-offset:1px}.exam-done{max-width:820px;margin:0 auto}.exam-result{text-align:center;background:var(--surface);border:1px solid var(--border);border-radius:18px;margin-bottom:34px;padding:36px 20px}.exam-result.pass{border-color:color-mix(in srgb, var(--green) 50%, var(--border))}.exam-result.fail{border-color:color-mix(in srgb, var(--red) 50%, var(--border))}.exam-result-score{letter-spacing:-.02em;font-size:3.4rem;font-weight:800;line-height:1}.pass .exam-result-score{color:var(--green)}.fail .exam-result-score{color:var(--red)}.exam-result-label{color:var(--muted);margin:10px 0 22px}.exam-result-actions{flex-wrap:wrap;justify-content:center;gap:12px;display:flex}.exam-review-title{margin:0 0 16px}.syncbadge{text-overflow:ellipsis;white-space:nowrap;border:1px solid var(--border2);max-width:160px;color:var(--muted);cursor:pointer;background:0 0;border-radius:9px;align-items:center;gap:7px;padding:7px 12px;font-size:.85rem;font-weight:650;display:inline-flex;overflow:hidden}.syncbadge:hover{background:var(--surface);color:var(--text)}.syncdot{background:var(--faint);border-radius:50%;flex:none;width:8px;height:8px}.syncbadge-synced .syncdot{background:var(--green)}.syncbadge-syncing .syncdot{background:var(--accent);animation:1s infinite alternate syncpulse}.syncbadge-offline .syncdot{background:var(--red)}@keyframes syncpulse{0%{opacity:.4}to{opacity:1}}.modal-scrim{z-index:90;background:#0000008c;justify-content:center;align-items:flex-start;padding:12vh 16px 16px;display:flex;position:fixed;inset:0}.modal{background:var(--surface);border:1px solid var(--border2);box-shadow:var(--shadow);border-radius:16px;width:100%;max-width:430px;padding:22px 24px}.modal h3{margin:0 0 8px;font-size:1.15rem}.modal p{color:var(--muted);margin:8px 0;font-size:.9rem;line-height:1.55}.modal-note{color:var(--faint)!important;font-size:.8rem!important}.modal-input{border:1px solid var(--border2);background:var(--surface2);width:100%;color:var(--text);font:inherit;border-radius:9px;margin-top:6px;padding:10px 12px;font-size:.95rem}.modal-input:focus{outline:2px solid var(--accent);outline-offset:1px;border-color:var(--accent)}.modal-error{color:var(--red)!important;font-size:.82rem!important}.modal-actions{justify-content:flex-end;gap:10px;margin-top:16px;display:flex}@media (width<=980px){.layout{grid-template-columns:1fr}.navtoggle{display:inline-flex}.sidebar{background:var(--bg);z-index:50;width:min(320px,85vw);height:auto;box-shadow:var(--shadow);transition:transform .2s;position:fixed;top:56px;bottom:0;left:0;transform:translate(-102%)}.sidebar.open{transform:translate(0)}.scrim{z-index:45;background:#00000073;display:block;position:fixed;inset:56px 0 0}.content{padding:24px 18px 60px}.global-progress{display:none}.syncbadge{max-width:110px}}@media (width<=640px){.topbar{padding:0 10px}.topbar-left,.topbar-right{gap:7px}.brand-text em{display:none}.btn-exam{padding:6px 10px;font-size:.8rem}.syncbadge{max-width:90px;padding:6px 9px;font-size:.78rem}.exam-body{grid-template-columns:1fr}.exam-palette{order:-1;position:static}.exam-choices{grid-template-columns:1fr}.brand-text{font-size:.9rem}}