#root{height:100dvh;min-height:100vh}:root{--bg-app:#0f1419;--bg-sidebar:#121820;--bg-card:#1a2332;--bg-card-hover:#1f2a3d;--border:#2a3548;--text:#e8edf4;--text-muted:#8b9cb3;--accent:#5b9fd4;--accent-soft:#3d6f9c;--difficulty-easy:#22c55e;--difficulty-easy-muted:#86efac;--difficulty-medium:#3b82f6;--difficulty-medium-muted:#93c5fd;--difficulty-hard:#f59e0b;--difficulty-hard-muted:#fcd34d;--difficulty-very-hard:#ef4444;--difficulty-very-hard-muted:#fca5a5;--radius:10px;color:var(--text);background:var(--bg-app);font-family:Segoe UI,system-ui,-apple-system,sans-serif}*{box-sizing:border-box}body{min-height:100vh;margin:0}a{color:inherit;text-decoration:none}.app-shell{height:100dvh;min-height:100vh;display:flex;overflow:hidden}.sidebar{background:var(--bg-sidebar);border-right:1px solid var(--border);flex-direction:column;flex-shrink:0;width:240px;padding:1.25rem .75rem;transition:width .2s;display:flex}.sidebar.collapsed{width:64px}.sidebar-brand{color:inherit;align-items:center;gap:.65rem;min-width:0;padding:0 .5rem 1.5rem .75rem;text-decoration:none;display:flex}.sidebar-brand:hover .sidebar-brand-title{color:var(--text)}.sidebar-brand-mascot{object-fit:contain;filter:drop-shadow(0 2px 6px #00000059);flex-shrink:0;width:36px;height:36px}.sidebar-brand-title{color:var(--accent);white-space:nowrap;text-overflow:ellipsis;font-size:1.35rem;font-weight:700;transition:color .15s;overflow:hidden}.sidebar.collapsed .sidebar-brand{justify-content:center;padding-left:.5rem;padding-right:.5rem}.sidebar.collapsed .sidebar-brand-title{display:none}.nav-list{flex:1;margin:0;padding:0;list-style:none}.nav-item a{border-radius:var(--radius);color:var(--text-muted);align-items:center;gap:.75rem;margin-bottom:.25rem;padding:.65rem .75rem;transition:background .15s,color .15s;display:flex}.nav-item a:hover,.nav-item a.active{background:var(--bg-card);color:var(--text)}.nav-icon{text-align:center;flex-shrink:0;width:20px}.sidebar.collapsed .nav-label{display:none}.collapse-btn{border:1px solid var(--border);color:var(--text-muted);border-radius:var(--radius);cursor:pointer;background:0 0;margin-top:auto;padding:.5rem;font-size:.85rem}.collapse-btn:hover{color:var(--text);border-color:var(--text-muted)}.main-content{flex:1;min-height:0;padding:2rem 2.5rem;overflow-y:auto}.page-title{margin:0 0 1.75rem;font-size:1.75rem;font-weight:700}.get-started{max-width:42rem}.get-started-hero .page-title{margin-bottom:.75rem}.get-started-lead{color:var(--text-muted);margin:0 0 2rem;font-size:1.05rem;line-height:1.65}.get-started-lead strong{color:var(--text)}.get-started-lead--secondary{margin-top:-1rem;font-size:.98rem}.get-started-path-grid{grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:1rem;display:grid}.get-started-path-card{border:1px solid var(--border);background:#0003;border-radius:8px;padding:1rem 1.1rem}.get-started-path-card h3{color:var(--accent);margin:0 0 .5rem;font-size:1rem}.get-started-path-card p{color:var(--text-muted);margin:0 0 .5rem;font-size:.9rem;line-height:1.55}.get-started-path-cta{margin-top:.75rem!important;font-size:.88rem!important}.get-started-path-cta a{color:var(--accent);text-decoration:underline}.get-started-section--local{border-color:var(--accent-soft)}.get-started-install-sub{color:var(--text);margin:1rem 0 .4rem;font-size:.88rem;font-weight:600}.get-started-install-block h4.get-started-install-sub:first-of-type{margin-top:.5rem}.get-started-steps kbd,.get-started-os-list kbd{border:1px solid var(--border);color:var(--text);background:#0000004d;border-radius:4px;padding:.1em .35em;font-family:inherit;font-size:.85em;display:inline-block}.get-started-section{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);margin-bottom:2rem;padding:1.25rem 1.35rem}.get-started-section h2{color:var(--text);margin:0 0 .85rem;font-size:1.1rem;font-weight:600}.get-started-section-intro{color:var(--text-muted);margin:0 0 1.25rem;font-size:.95rem;line-height:1.55}.get-started-install-block{border-bottom:1px solid var(--border);margin-bottom:1.35rem;padding-bottom:1.25rem}.get-started-install-block:last-of-type{border-bottom:none;margin-bottom:0;padding-bottom:0}.get-started-install-block h3{color:var(--accent);margin:0 0 .5rem;font-size:.95rem;font-weight:600}.get-started-install-block p{color:var(--text-muted);margin:0 0 .5rem;font-size:.92rem;line-height:1.55}.get-started-install-block a{color:var(--accent);text-underline-offset:.15em;text-decoration:underline}.get-started-install-note{margin-top:.65rem!important;font-size:.85rem!important}.get-started-os-list{color:var(--text-muted);margin:.35rem 0 0;padding-left:1.15rem;font-size:.9rem;line-height:1.55}.get-started-os-list li{margin-bottom:.4rem}.get-started-os-list--blocks li{margin-bottom:1.1rem}.get-started-os-list--blocks .code-block{margin-top:.35rem}.get-started-os-list strong{color:var(--text)}.get-started-verify{border-top:1px solid var(--border);margin-top:1.25rem;padding-top:1.15rem}.get-started-verify p{color:var(--text-muted);margin:0 0 .5rem;font-size:.92rem}.code-block{margin:.5rem 0;position:relative}.code-block-pre{border:1px solid var(--border);background:#0000004d;border-radius:6px;margin:0;padding:.75rem 5.5rem .75rem 1rem;font-size:.88rem;line-height:1.6;overflow-x:auto}.code-block-pre code{color:var(--accent);white-space:pre;background:0 0;padding:0}.code-block-copy{color:var(--text-muted);border:1px solid var(--border);cursor:pointer;background:#ffffff0f;border-radius:4px;align-items:center;gap:.35rem;padding:.3rem .55rem;font-family:inherit;font-size:.75rem;transition:color .15s,background .15s,border-color .15s;display:inline-flex;position:absolute;top:.45rem;right:.45rem}.code-block-copy:hover{color:var(--text);border-color:var(--accent);background:#ffffff1a}.code-block-copy:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.code-block-copy-feedback{color:#4ade80;font-size:.9rem;font-weight:600}.code-block-copy-icon{opacity:.85;flex-shrink:0}.code-block-copy-label{line-height:1}@media (width<=480px){.code-block-copy-label{clip:rect(0, 0, 0, 0);white-space:nowrap;border:0;width:1px;height:1px;margin:-1px;padding:0;position:absolute;overflow:hidden}.code-block-pre{padding-right:2.75rem}}.get-started-verify-hint{font-size:.85rem!important}.get-started-section--compact{padding-bottom:1rem}.js-basics-skip{border-top:1px solid var(--border);margin-top:2rem;padding-top:.5rem}.js-basics-optional{margin-bottom:1.5rem}.js-basics-optional-heading{margin:0 0 .35rem;font-size:1.15rem;font-weight:600}.js-basics-optional-intro{color:var(--text-muted);margin:0 0 1rem;font-size:.92rem;line-height:1.55}.js-basics-optional-intro code{color:var(--accent);background:#00000040;border-radius:4px;padding:.12em .4em;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:.88em}.js-basics-optional .js-basics-item{background:#0000001f;border-color:#8b9cb359}.js-basics-optional .js-basics-num{color:var(--text-muted);background:#8b9cb333}.js-basics{max-width:44rem}.js-basics-hero-actions{flex-wrap:wrap;align-items:center;gap:1rem 1.25rem;margin-top:.5rem;display:flex}.js-basics-hero-cta{margin:0}.js-basics-tutorial-launch{border-radius:var(--radius);color:var(--text);cursor:pointer;background:linear-gradient(135deg,#5b9fd438,#863bff2e);border:1px solid #5b9fd48c;align-items:center;gap:.5rem;padding:.65rem 1.15rem;font-size:.95rem;font-weight:600;transition:background .15s,border-color .15s,transform .12s;display:inline-flex}.js-basics-tutorial-launch:hover{border-color:var(--accent);background:linear-gradient(135deg,#5b9fd459,#863bff47)}.js-basics-tutorial-launch:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.js-basics-tutorial-launch-icon{background:#5b9fd459;border-radius:999px;justify-content:center;align-items:center;width:1.35rem;height:1.35rem;font-size:.65rem;display:inline-flex}.js-basics-item--tutorial-active{border-color:#5b9fd4a6;box-shadow:0 0 0 1px #5b9fd440}.js-basics-why--tutorial-active{color:var(--text)}body.js-basics-tutorial-open{overflow:hidden}.js-basics-tutorial-root{z-index:1000;pointer-events:none;position:fixed;inset:0}.js-basics-tutorial-backdrop{pointer-events:auto;background:#0000008c;position:absolute;inset:0}.js-basics-tutorial-spotlight{pointer-events:none;z-index:1001;border-radius:12px;animation:1.6s ease-in-out infinite tutorial-spotlight-pulse;position:fixed;box-shadow:0 0 0 9999px #000000b8}@keyframes tutorial-spotlight-pulse{0%,to{outline-offset:2px;outline:2px solid #5b9fd4d9}50%{outline-offset:4px;outline:3px solid #c4b5fde6}}.js-basics-tutorial-dialog{z-index:1002;border:1px solid var(--border);pointer-events:auto;box-sizing:border-box;background:#141c28;border-radius:12px;width:min(32rem,100vw - 2rem);max-height:calc(100dvh - 2.5rem);padding:1rem 1.15rem .85rem;position:fixed;bottom:1.25rem;left:50%;overflow:hidden;transform:translate(-50%);box-shadow:0 20px 50px #0000008c}.js-basics-tutorial-dialog .react-term-tip{max-width:min(16rem,100% - .5rem)}.js-basics-tutorial-progress{background:#ffffff14;border-radius:999px;height:4px;margin:-.25rem 0 .75rem;overflow:hidden}.js-basics-tutorial-progress-fill{border-radius:inherit;background:linear-gradient(90deg, var(--accent), #a78bfa);height:100%;transition:width .25s}.js-basics-tutorial-step-label{letter-spacing:.06em;text-transform:uppercase;color:var(--text-muted);margin:0 0 .35rem;font-size:.72rem;font-weight:600}.js-basics-tutorial-title{color:var(--text);margin:0 0 .5rem;font-size:1.1rem;font-weight:700}.js-basics-tutorial-body{color:var(--text-muted);overflow-wrap:break-word;word-break:break-word;margin:0 0 .65rem;font-size:.92rem;line-height:1.5}.js-basics-tutorial-body code{color:var(--accent)}.js-basics-tutorial-tip{color:var(--text-muted);overflow-wrap:break-word;word-break:break-word;background:#863bff1f;border-left:3px solid #a78bfa;border-radius:8px;margin:0 0 .65rem;padding:.5rem .6rem;font-size:.85rem;line-height:1.4}.js-basics-tutorial-tip-label{letter-spacing:.08em;text-transform:uppercase;color:#c4b5fd;margin-bottom:.2rem;font-size:.68rem;font-weight:700;display:block}.js-basics-tutorial-actions{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:.5rem .75rem;margin-top:.25rem;display:flex}.js-basics-tutorial-actions-main{gap:.5rem;display:flex}.js-basics-tutorial-btn{border:1px solid var(--border);color:var(--text);cursor:pointer;background:0 0;border-radius:8px;padding:.45rem .85rem;font-size:.88rem;font-weight:500;transition:background .15s,border-color .15s}.js-basics-tutorial-btn:hover:not(:disabled){border-color:var(--accent-soft);background:#ffffff0f}.js-basics-tutorial-btn:disabled{opacity:.4;cursor:not-allowed}.js-basics-tutorial-btn--primary{background:#5b9fd433;border-color:#5b9fd499;font-weight:600}.js-basics-tutorial-btn--primary:hover:not(:disabled){background:#5b9fd459}.js-basics-tutorial-btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.js-basics-tutorial-hint{color:var(--text-muted);opacity:.75;text-align:center;margin:.5rem 0 0;font-size:.72rem}@media (height<=720px){.js-basics-tutorial-dialog{padding:.75rem 1rem .7rem}.js-basics-tutorial-title{margin-bottom:.35rem;font-size:1rem}.js-basics-tutorial-body{margin-bottom:.5rem;font-size:.88rem}.js-basics-tutorial-tip{margin-bottom:.5rem;font-size:.82rem}}.tutorial-code-mark{color:#fde68a;background:#fbbf2447;border-radius:3px;padding:0 .1em;animation:1.4s ease-in-out infinite tutorial-code-mark-pulse}@keyframes tutorial-code-mark-pulse{0%,to{background:#fbbf2447}50%{background:#fbbf2480}}.code-block-pre--highlighted .tutorial-code-mark{-webkit-box-decoration-break:clone;box-decoration-break:clone}.js-basics-list{flex-direction:column;gap:1.5rem;margin:0 0 2rem;padding:0;list-style:none;display:flex}.js-basics-item{border:1px solid var(--border);background:#0003;border-radius:8px;padding:1rem 1.1rem}.js-basics-item-title{align-items:center;gap:.6rem;margin:0 0 .4rem;font-size:1.05rem;font-weight:600;display:flex}.js-basics-num{color:#fbbf24;background:#fbbf2426;border-radius:999px;flex-shrink:0;justify-content:center;align-items:center;width:1.5rem;height:1.5rem;font-size:.75rem;font-weight:700;display:inline-flex}.js-basics-why{color:var(--text-muted);margin:0 0 .65rem;font-size:.92rem;line-height:1.55}.js-basics-why:last-of-type{margin-bottom:.75rem}.js-basics-why code,.js-basics .get-started-lead code,.get-started-section-intro code{color:var(--accent);background:#00000040;border-radius:4px;padding:.12em .4em;font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:.88em}.react-term-inline-sample{color:#c4b5fd;border-bottom:1px dashed #c4b5fd99;font-weight:600}.react-term{white-space:normal;display:inline;position:relative}.react-term-trigger{color:#ddd6fe;font:inherit;cursor:help;vertical-align:baseline;background:#863bff2e;border:none;border-radius:3px;margin:0;padding:0 .12em;font-weight:600;text-decoration:none;display:inline;box-shadow:inset 0 -1px #c4b5fd73}.react-term-trigger:hover,.react-term-trigger:focus-visible{outline-offset:1px;background:#863bff52;outline:2px solid #c4b5fd8c}.react-term-tip{z-index:20;border:1px solid var(--border);width:min(18rem,100vw - 3rem);color:var(--text-muted);text-align:left;pointer-events:none;opacity:0;visibility:hidden;background:#1a2332;border-radius:8px;padding:.65rem .75rem;font-size:.82rem;font-weight:400;line-height:1.45;transition:opacity .15s,transform .15s,visibility .15s;position:absolute;top:calc(100% + .45rem);left:0;transform:translateY(-4px);box-shadow:0 12px 32px #00000073}.react-term-tip strong{color:#c4b5fd;letter-spacing:.04em;text-transform:uppercase;margin-bottom:.25rem;font-size:.78rem;display:block}.react-term:hover .react-term-tip,.react-term:focus-within .react-term-tip{opacity:1;visibility:visible;transform:translateY(0)}.react-code-terms{background:#863bff0f;border:1px dashed #863bff59;border-radius:8px;margin-top:.65rem;padding:.65rem .75rem}.react-code-terms-label{letter-spacing:.03em;text-transform:uppercase;color:#a78bfa;margin-bottom:.45rem;font-size:.78rem;font-weight:600;display:block}.react-code-terms-list{flex-wrap:wrap;gap:.35rem .5rem;margin:0;padding:0;list-style:none;display:flex}.react-code-terms-list li{margin:0}.get-started-steps{color:var(--text-muted);margin:0;padding-left:1.25rem;line-height:1.65}.get-started-steps li{margin-bottom:.65rem}.get-started-steps li:last-child{margin-bottom:0}.get-started-steps strong{color:var(--text)}.get-started-steps a{color:var(--accent);text-underline-offset:.15em;text-decoration:none}.get-started-steps a:hover{color:#7eb8e8;text-decoration:underline}.get-started-steps code,.get-started-links code{color:var(--accent);background:#00000040;border-radius:4px;padding:.12em .4em;font-size:.88em}.get-started-links,.get-started-pointers{color:var(--text-muted);margin:0;padding-left:1.25rem;line-height:1.65}.get-started-links a,.get-started-pointers a{color:var(--accent);text-underline-offset:.15em;text-decoration:underline}.get-started-links a:hover,.get-started-pointers a:hover{color:#7eb8e8}.get-started-pointers li{margin-bottom:.5rem}.get-started-cta{flex-wrap:wrap;gap:.75rem;margin-top:2rem;display:flex}.get-started-cta-btn{border-radius:var(--radius);border:1px solid var(--border);color:var(--text);padding:.6rem 1.1rem;font-size:.95rem;font-weight:500;transition:background .15s,border-color .15s;display:inline-block}.get-started-cta-btn:hover{background:var(--bg-card-hover);border-color:var(--text-muted)}.get-started-cta-btn.primary{background:var(--accent-soft);border-color:var(--accent);color:#fff}.get-started-cta-btn.primary:hover{background:var(--accent)}.flashcard-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem;display:grid}.flashcard-section-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);cursor:pointer;min-height:100px;padding:1.25rem 1.35rem;transition:background .15s,border-color .15s;position:relative}.flashcard-section-card:hover{background:var(--bg-card-hover);border-color:var(--accent-soft)}.flashcard-section-card h3{margin:0 0 .5rem;padding-right:3rem;font-size:1.05rem;font-weight:600}.flashcard-section-card p{color:var(--text-muted);margin:0;font-size:.9rem}.flashcard-completed-badge{color:#86efac;text-transform:capitalize;background:#22543d59;border:1px solid #3d6b4f;border-radius:999px;align-items:center;padding:.2rem .6rem;font-size:.75rem;font-weight:600;display:inline-flex}.flashcard-completed-badge--small{font-size:.65rem;position:absolute;top:1rem;right:1rem}.flashcard-study{max-width:52rem}.flashcard-study-header{margin-bottom:2rem}.flashcard-study-title-row{flex-wrap:wrap;align-items:center;gap:1rem;margin-bottom:.35rem;display:flex}.flashcard-study-title{margin:0;font-size:1.75rem;font-weight:700;line-height:1.2}.flashcard-study-progress{color:var(--text-muted);margin:0;font-size:.95rem}.flashcard-question-block{margin-bottom:2rem}.flashcard-question{color:var(--text);letter-spacing:-.01em;margin:0;font-size:clamp(1.25rem,2.5vw,1.6rem);font-weight:600;line-height:1.45}.flashcard-card-complete{cursor:pointer;color:var(--text-muted);-webkit-user-select:none;user-select:none;align-items:center;gap:.6rem;margin-bottom:1.5rem;font-size:.9rem;display:flex}.flashcard-card-complete input{width:1rem;height:1rem;accent-color:var(--accent);cursor:pointer}.flashcard-card-complete:has(input:checked) span{color:#86efac}.flashcard-explanation-block{margin-bottom:2.5rem}.flashcard-explanation-toggle{text-align:left;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);width:100%;color:var(--text);cursor:pointer;align-items:center;gap:.5rem;padding:.85rem 1.1rem;font-size:.95rem;font-weight:600;transition:border-color .15s,background .15s;display:flex}.flashcard-explanation-toggle:hover{border-color:var(--accent-soft);background:var(--bg-card-hover)}.flashcard-explanation-chevron{color:var(--accent);font-size:1.1rem;line-height:1;transition:transform .2s;display:inline-block;transform:rotate(90deg)}.flashcard-explanation-chevron[data-open=true]{transform:rotate(-90deg)}.flashcard-explanation-panel{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);margin-top:.75rem;padding:1.5rem 1.75rem}.flashcard-explanation-heading{color:var(--text);margin:0 0 1rem;font-size:1rem;font-weight:700}.flashcard-study-progress-sep{opacity:.5}.flashcard-study-progress-muted{color:var(--text-muted);font-size:.9em}.flashcard-hidden-tooltip{display:inline;position:relative}.flashcard-hidden-tooltip-trigger{font:inherit;color:var(--text-muted);cursor:help;text-underline-offset:.2em;background:0 0;border:none;margin:0;padding:0;font-size:.9em;-webkit-text-decoration:underline dotted;text-decoration:underline dotted;display:inline}.flashcard-hidden-tooltip-trigger:hover,.flashcard-hidden-tooltip-trigger:focus-visible{color:var(--accent);outline:none}.flashcard-hidden-tooltip-popup{z-index:50;background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);min-width:18rem;max-width:min(24rem,90vw);max-height:16rem;color:var(--text);text-align:left;pointer-events:none;opacity:0;visibility:hidden;padding:.35rem .75rem .65rem;font-size:.8rem;line-height:1.4;transition:opacity .15s,transform .15s,visibility .15s;position:absolute;top:100%;left:0;overflow-y:auto;transform:translateY(-4px);box-shadow:0 8px 24px #00000059}.flashcard-hidden-tooltip[data-open] .flashcard-hidden-tooltip-popup{opacity:1;visibility:visible;pointer-events:auto;transform:translateY(0)}.flashcard-hidden-tooltip-header{justify-content:space-between;align-items:center;gap:.5rem;margin-bottom:.5rem;padding-top:.65rem;display:flex}.flashcard-hidden-tooltip-heading{text-transform:uppercase;letter-spacing:.04em;color:var(--text-muted);font-size:.75rem;font-weight:600;display:block}.flashcard-hidden-tooltip-uncomplete-all{border:1px solid var(--border);color:var(--accent);cursor:pointer;background:0 0;border-radius:4px;flex-shrink:0;padding:.2rem .45rem;font-size:.7rem;font-weight:500}.flashcard-hidden-tooltip-uncomplete-all:hover,.flashcard-hidden-tooltip-uncomplete-all:focus-visible{background:#8b5cf61f;outline:none}.flashcard-hidden-tooltip-list{margin:0;padding:0;list-style:none}.flashcard-hidden-tooltip-list li{border-bottom:1px solid var(--border);justify-content:space-between;align-items:flex-start;gap:.5rem;padding:.4rem 0;display:flex}.flashcard-hidden-tooltip-item-text{flex:1;align-items:flex-start;gap:.5rem;min-width:0;display:flex}.flashcard-hidden-tooltip-uncomplete{color:var(--accent);cursor:pointer;white-space:nowrap;background:#8b5cf626;border:none;border-radius:4px;flex-shrink:0;padding:.2rem .5rem;font-size:.7rem;font-weight:500}.flashcard-hidden-tooltip-uncomplete:hover,.flashcard-hidden-tooltip-uncomplete:focus-visible{background:#8b5cf647;outline:none}.flashcard-hidden-tooltip-list li:last-child{border-bottom:none;padding-bottom:0}.flashcard-hidden-tooltip-num{color:var(--accent);flex-shrink:0;font-size:.75rem;font-weight:600}.flashcard-hidden-tooltip-preview{color:var(--text)}.flashcard-filter-toggle{cursor:pointer;color:var(--text-muted);-webkit-user-select:none;user-select:none;align-items:center;gap:.55rem;margin-top:1rem;font-size:.9rem;display:flex}.flashcard-filter-toggle input{width:1rem;height:1rem;accent-color:var(--accent);cursor:pointer}.flashcard-filter-toggle:has(input:checked) span{color:var(--text)}.flashcard-study-empty{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);text-align:center;max-width:28rem;padding:2.5rem 2rem}.flashcard-study-empty p{color:var(--text);margin:0 0 .75rem;font-size:1.05rem}.flashcard-study-empty-hint{color:var(--text-muted)!important;margin-bottom:1.5rem!important;font-size:.95rem!important}.flashcard-study-empty .primary{background:var(--accent-soft);border:1px solid var(--accent);color:var(--text);border-radius:var(--radius);cursor:pointer;margin-bottom:1.25rem;padding:.55rem 1.25rem;font-size:.95rem;display:inline-block}.flashcard-study-empty-back{display:block}.flashcard-explanation-body p{color:var(--text-muted);max-width:42rem;margin:0 0 1rem;font-size:.98rem;line-height:1.65}.flashcard-explanation-body p:last-child{margin-bottom:0}.flashcard-explanation-body .flashcard-explanation-code{max-width:42rem;margin:0 0 1rem}.flashcard-explanation-body .flashcard-explanation-code:last-child{margin-bottom:0}.flashcard-study-footer{border-top:1px solid var(--border);flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;padding-top:1rem;display:flex}.flashcard-back-link{color:var(--accent);font-size:.9rem}.flashcard-study-controls{flex-wrap:wrap;gap:.75rem;display:flex}.flashcard-study-controls button{background:var(--bg-card);border:1px solid var(--border);color:var(--text);border-radius:var(--radius);cursor:pointer;padding:.55rem 1.2rem;font-size:.95rem}.flashcard-study-controls button:hover:not(:disabled){border-color:var(--accent)}.flashcard-study-controls button:disabled{opacity:.45;cursor:not-allowed}.flashcard-study-controls button.primary{background:var(--accent-soft);border-color:var(--accent);min-width:7rem}.challenge-filters{flex-wrap:wrap;gap:.5rem;margin-bottom:1.5rem;display:flex}.challenge-filters button{background:var(--bg-card);border:1px solid var(--border);color:var(--text-muted);cursor:pointer;border-radius:999px;padding:.4rem .9rem}.challenge-filters button.active{border-color:var(--accent);color:var(--text)}.challenge-filters__btn--easy.active{color:var(--difficulty-easy-muted);border-color:var(--difficulty-easy);background:#22c55e1f}.challenge-filters__btn--medium.active{color:var(--difficulty-medium-muted);border-color:var(--difficulty-medium);background:#3b82f61f}.challenge-filters__btn--hard.active{color:var(--difficulty-hard-muted);border-color:var(--difficulty-hard);background:#f59e0b1f}.challenge-filters__btn--very-hard.active{color:var(--difficulty-very-hard-muted);border-color:var(--difficulty-very-hard);background:#ef44441f}.challenge-list{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem;margin:0;padding:0;list-style:none;display:grid}.challenge-list li{margin-bottom:0}.challenge-list-lead{color:var(--text-muted);margin:-1rem 0 1.5rem}.challenge-list-card{color:inherit;text-decoration:none;display:block}.challenge-list-card h3{margin:0;padding-right:.25rem;font-size:1.05rem;font-weight:600;line-height:1.35}.challenge-list-card:hover h3{color:inherit}.challenge-list-card-top{align-items:center;gap:.5rem;margin-bottom:.5rem;display:flex}.challenge-completed-badge{color:#86efac;background:#22543d59;border:1px solid #3d6b4f;border-radius:999px;flex-shrink:0;align-items:center;padding:.2rem .6rem;font-size:.75rem;font-weight:600;display:inline-flex}.challenge-completed-badge--small{padding:.15rem .5rem;font-size:.65rem;position:absolute;top:1rem;right:1rem}.challenge-detail-header{flex-wrap:wrap;align-items:center;gap:1rem;margin-bottom:1.5rem;display:flex}.challenge-detail-title-row{flex-wrap:wrap;flex:1;align-items:center;gap:.75rem;min-width:0;display:flex}.challenge-detail-header .page-title{margin:0}.difficulty-badge--detail{padding:.25rem .65rem;font-size:.75rem}.challenge-breadcrumbs{color:var(--text-muted);flex-wrap:wrap;align-items:center;gap:.35rem;margin-bottom:1rem;font-size:.9rem;display:flex}.challenge-breadcrumbs a{color:var(--accent)}.challenge-acceptance{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);margin:2rem 0;padding:1.25rem 1.5rem}.challenge-acceptance-header{flex-wrap:wrap;justify-content:space-between;align-items:center;gap:1rem;display:flex}.challenge-acceptance h2,.challenge-resources h2{margin:0 0 .75rem;font-size:1.1rem}.challenge-acceptance-progress{color:var(--text-muted);margin:0 0 1rem;font-size:.85rem}.challenge-acceptance-intro{color:var(--text-muted);margin:0 0 .5rem;font-size:.9rem;line-height:1.5}.challenge-acceptance-list{margin:0;padding:0;list-style:none}.challenge-acceptance-item{border-bottom:1px solid var(--border);cursor:pointer;align-items:flex-start;gap:.75rem;padding:.65rem 0;line-height:1.45;display:flex}.challenge-acceptance-item:last-child{border-bottom:none}.challenge-acceptance-item input{width:1rem;height:1rem;accent-color:var(--accent);flex-shrink:0;margin-top:.2rem}.challenge-acceptance-text{flex-direction:column;gap:.35rem;min-width:0;display:flex}.challenge-acceptance-summary{color:var(--text);font-weight:600}.challenge-acceptance-detail{color:var(--text-muted);font-size:.88rem;font-weight:400;line-height:1.5}.markdown-table-wrap{-webkit-overflow-scrolling:touch;max-width:52rem;margin:0 0 1.25rem;overflow-x:auto}.markdown table{border-collapse:collapse;width:100%;font-size:.9rem;line-height:1.55}.markdown th,.markdown td{border:1px solid var(--border);text-align:left;vertical-align:top;padding:.6rem .85rem}.markdown th{background:var(--bg-card);color:var(--text);font-weight:600}.markdown td{color:var(--text-muted)}.markdown tbody tr:nth-child(2n) td{background:#ffffff05}.markdown a code{color:var(--accent);text-underline-offset:.12em;text-decoration:underline}.markdown a:hover code{color:#7eb8e8}.challenge-resources{margin:2rem 0}.challenge-resource-list{margin:0;padding:0;list-style:none}.challenge-resource-list li{margin-bottom:.5rem}.challenge-resource-list a{color:var(--accent);font-weight:500;text-decoration:none}.challenge-resource-list a:hover{text-decoration:underline}.solution-panel{border-top:1px solid var(--border);margin:2rem 0;padding-top:1.5rem}.solution-toggle{background:var(--bg-card);border:1px solid var(--border);color:var(--text);border-radius:var(--radius);cursor:pointer;padding:.55rem 1.1rem;font-size:.95rem}.solution-toggle:hover{border-color:var(--accent)}.solution-content{margin-top:1.25rem}.solution-code-hint{color:var(--text-muted);margin:0 0 1rem;font-size:.88rem;line-height:1.5}.solution-code-term-inline-sample{color:#5eead4;border-bottom:1px dashed #5eead499;font-weight:600}.solution-code-block-wrap{margin:0 0 1rem}.solution-code-pre{border-radius:var(--radius);background:var(--bg-card);border:1px solid var(--border);text-align:left;margin:0;padding:1rem;font-size:.85rem;line-height:1.5;overflow-x:auto}.solution-code-pre code{font-family:ui-monospace,SFMono-Regular,Menlo,Monaco,Consolas,monospace;font-size:inherit;white-space:pre;background:0 0;padding:0}.solution-code-term{white-space:pre-wrap;display:inline;position:relative}.solution-code-term-trigger{color:#99f6e4;font:inherit;cursor:help;vertical-align:baseline;background:#2dd4bf33;border:none;border-radius:3px;margin:0;padding:0 .1em;font-weight:600;text-decoration:none;display:inline;box-shadow:inset 0 -1px #5eead473}.solution-code-term-trigger:hover,.solution-code-term-trigger:focus-visible{outline-offset:1px;background:#2dd4bf59;outline:2px solid #5eead48c}.solution-code-term-tip{z-index:25;border:1px solid var(--border);width:min(17rem,100vw - 3rem);color:var(--text-muted);text-align:left;white-space:normal;pointer-events:none;opacity:0;visibility:hidden;background:#142a28;border-radius:8px;padding:.65rem .75rem;font-size:.82rem;font-weight:400;line-height:1.45;transition:opacity .15s,transform .15s,visibility .15s;position:absolute;top:calc(100% + .45rem);left:0;transform:translateY(-4px);box-shadow:0 12px 32px #00000073}.solution-code-term-tip strong{color:#5eead4;letter-spacing:.04em;text-transform:uppercase;margin-bottom:.25rem;font-size:.78rem;display:block}.solution-code-term:hover .solution-code-term-tip,.solution-code-term:focus-within .solution-code-term-tip{opacity:1;visibility:visible;transform:translateY(0)}.solution-code-terms{background:#2dd4bf14;border:1px solid #5eead433;border-radius:8px;margin:.5rem 0 0;padding:.55rem .65rem}.solution-code-terms-label{letter-spacing:.06em;text-transform:uppercase;color:#5eead4;margin-bottom:.35rem;font-size:.68rem;font-weight:700;display:block}.solution-code-terms-list{flex-wrap:wrap;gap:.35rem .65rem;margin:0;padding:0;list-style:none;display:flex}.solution-code-terms-list li{margin:0}.challenge-nav{border-top:1px solid var(--border);margin-top:2rem;padding-top:1rem}.challenge-nav a{color:var(--accent)}.challenge-detail{max-width:800px}.challenge-detail pre{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);padding:1rem;font-size:.85rem;overflow-x:auto}.challenge-tabs{gap:.5rem;margin-bottom:1rem;display:flex}.challenge-tabs button{background:var(--bg-card);border:1px solid var(--border);color:var(--text-muted);border-radius:var(--radius);cursor:pointer;padding:.45rem 1rem}.challenge-tabs button.active{color:var(--text);border-color:var(--accent)}.difficulty-badge{text-transform:uppercase;letter-spacing:.04em;border:1px solid;border-radius:999px;flex-shrink:0;align-items:center;padding:.2rem .55rem;font-size:.7rem;font-weight:600;line-height:1.2;display:inline-flex}.difficulty-badge--easy{color:var(--difficulty-easy-muted);background:#22c55e24;border-color:#22c55e73}.difficulty-badge--medium{color:var(--difficulty-medium-muted);background:#3b82f624;border-color:#3b82f673}.difficulty-badge--hard{color:var(--difficulty-hard-muted);background:#f59e0b24;border-color:#f59e0b73}.difficulty-badge--very-hard{color:var(--difficulty-very-hard-muted);background:#ef444424;border-color:#ef444473}.placeholder-page{color:var(--text-muted);max-width:480px}.markdown-body h1{margin-top:0;font-size:1.5rem}.markdown-body h2{margin-top:1.5rem;font-size:1.15rem}.markdown-body ul{padding-left:1.25rem}.markdown-body code{background:var(--bg-card);border-radius:4px;padding:.15rem .35rem;font-size:.9em}.markdown-body pre code{background:0 0;padding:0;display:block}.system-design-grid{grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:1rem;display:grid}.system-design-card{background:var(--bg-card);border:1px solid var(--border);border-radius:var(--radius);min-height:100px;padding:1.25rem 1.35rem;transition:background .15s,border-color .15s,box-shadow .15s;position:relative;overflow:hidden}.system-design-card:before{content:"";background:0 0;height:3px;transition:background .15s;position:absolute;top:0;left:0;right:0}.system-design-card:hover{background:var(--bg-card-hover);border-color:var(--accent-soft);box-shadow:0 4px 20px #00000040}.system-design-card:hover:before{background:linear-gradient(90deg,#7c3aed,#a78bfa)}.system-design-card h3{margin:0 0 .5rem;font-size:1.05rem;font-weight:600}.system-design-card p{color:var(--text-muted);margin:0;font-size:.9rem;line-height:1.4}.system-design-detail{max-width:52rem}.sd-back-link{color:var(--accent);margin-bottom:1.5rem;font-size:.9rem;display:inline-block}.sd-back-link:hover{text-decoration:underline}.system-design-prose .markdown h1{letter-spacing:-.02em;margin:0 0 1.25rem;font-size:clamp(1.5rem,3vw,1.85rem);font-weight:700;line-height:1.25}.system-design-prose .markdown h2{border-top:1px solid var(--border);color:var(--text);margin:2.25rem 0 .85rem;padding-top:.5rem;font-size:1.2rem;font-weight:700}.system-design-prose .markdown h2:first-of-type{border-top:none;margin-top:1rem;padding-top:0}.system-design-prose .markdown h3{color:var(--accent);margin:1.5rem 0 .65rem;font-size:1.05rem;font-weight:600}.system-design-prose .markdown p{color:var(--text-muted);max-width:46rem;margin:0 0 1rem;line-height:1.7}.system-design-prose .markdown ul,.system-design-prose .markdown ol{color:var(--text-muted);max-width:46rem;margin:0 0 1.25rem;padding-left:1.35rem;line-height:1.65}.system-design-prose .markdown li{margin-bottom:.45rem}.system-design-prose .markdown li strong{color:var(--text)}.system-design-prose .markdown pre{border:1px solid var(--border);border-radius:var(--radius);background:#0a0e14;margin:0 0 1.5rem;padding:1rem 1.15rem;font-size:.82rem;line-height:1.55;overflow-x:auto}.system-design-prose .markdown pre code{color:#c9d7e8;background:0 0;padding:0;font-family:Cascadia Code,Fira Code,Consolas,monospace}.system-design-prose .markdown code{background:var(--bg-card);border:1px solid var(--border);color:#b8d4f0;border-radius:4px;padding:.12rem .4rem;font-size:.88em}.system-design-prose .markdown table{border-collapse:collapse;width:100%;font-size:.9rem;line-height:1.55}.system-design-prose .markdown th,.system-design-prose .markdown td{border:1px solid var(--border);text-align:left;vertical-align:top;padding:.65rem .9rem}.system-design-prose .markdown th{background:var(--bg-card);color:var(--text);white-space:nowrap;font-weight:600}.system-design-prose .markdown td{color:var(--text-muted)}.system-design-prose .markdown tbody tr:nth-child(2n) td{background:#ffffff05}.system-design-prose .markdown tbody tr:hover td{background:#8b5cf60f}.system-design-prose .markdown td strong,.system-design-prose .markdown th strong{color:var(--text)}