:root{--bg:#0a0e17;--surface:#0f1729;--surface2:#1a2440;--border:#1e293b;--text:#e2e8f0;--text2:#94a3b8;--muted:#64748b;--pal-bg:#0a0e17;--pal-surface:#0f1729;--pal-border:#1e293b;--pal-text:#e2e8f0;--pal-muted:#64748b;--pal-node-bg:#1a2440;--pal-node-border:#2a3a55;--accent:#3b82f6;--accent2:#22c55e;--danger:#ef4444;--font:Inter,system-ui,-apple-system,sans-serif}
[data-theme=light]{--bg:#f8fafc;--surface:#fff;--surface2:#f1f5f9;--border:#e2e8f0;--text:#0f172a;--text2:#475569;--muted:#94a3b8;--pal-bg:#f1f5f9;--pal-surface:#fff;--pal-border:#e2e8f0;--pal-text:#0f172a;--pal-muted:#94a3b8;--pal-node-bg:#fff;--pal-node-border:#cbd5e1}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{font-size:16px}
body{font-family:var(--font);background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden;line-height:1.5}
#app{max-width:1200px;margin:0 auto;padding:12px}
@media(max-width:768px){#app{padding:8px}}
.skeleton{position:relative;overflow:hidden;border-radius:12px;background:var(--surface);min-height:400px}
.skeleton-shimmer{position:absolute;inset:0;background:linear-gradient(90deg,transparent,rgba(59,130,246,0.08),transparent);animation:shimmer 2s infinite;pointer-events:none}
@keyframes shimmer{0%{transform:translateX(-100%)}100%{transform:translateX(100%)}}
.skeleton-header{padding:24px;display:flex;flex-direction:column;gap:12px}
.skeleton-body{padding:24px;display:flex;flex-direction:column;gap:16px}
.skeleton-line{height:16px;border-radius:8px;background:var(--surface2);animation:shimmer 2s infinite}
.skeleton-block{border-radius:12px;background:var(--surface2);animation:shimmer 2s infinite}
.w-60{width:60%}.w-40{width:40%}.h-64{height:256px}.h-32{height:128px}
.error-boundary{display:flex;flex-direction:column;align-items:center;gap:16px;padding:48px 24px;text-align:center;background:var(--surface);border-radius:12px;border:1px solid var(--danger)}
.error-icon{font-size:48px}
.error-boundary h2{font-size:20px;color:var(--danger)}
.btn-primary{padding:12px 24px;min-height:48px;border:none;border-radius:8px;background:var(--accent);color:#fff;font-family:var(--font);font-size:14px;font-weight:600;cursor:pointer;transition:opacity 0.2s,transform 0.1s}
.btn-primary:hover{opacity:0.9}
.btn-primary:active{transform:scale(0.97)}
.btn-primary:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.icon-btn{width:44px;height:44px;min-width:44px;border-radius:8px;border:1px solid var(--border);background:var(--surface);color:var(--text);font-size:18px;cursor:pointer;display:flex;align-items:center;justify-content:center}
.icon-btn:hover{background:var(--surface2)}
.app-header{margin-bottom:12px}
.header-top{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;flex-wrap:wrap}
.app-title{font-size:22px;font-weight:700}
.app-subtitle{font-size:13px;color:var(--text2)}
.header-controls{display:flex;align-items:center;gap:10px;flex-wrap:wrap}
.speed-control{display:flex;align-items:center;gap:6px}
.speed-label{font-size:11px;color:var(--muted)}
.speed-slider{width:100px;height:4px;-webkit-appearance:none;appearance:none;background:var(--border);border-radius:2px;outline:none;cursor:pointer}
.speed-slider::-webkit-slider-thumb{-webkit-appearance:none;width:16px;height:16px;border-radius:50%;background:var(--accent);cursor:pointer;border:2px solid var(--bg)}
.diagram-layout{display:grid;grid-template-columns:1fr 320px;gap:12px;margin-bottom:16px}
@media(max-width:900px){.diagram-layout{grid-template-columns:1fr}}
.svg-container{background:var(--pal-surface);border-radius:12px;border:1px solid var(--border);overflow:hidden;width:100%}
.diagram-svg{width:100%;height:auto;display:block;min-height:300px}
.node-list{display:flex;flex-direction:column;gap:6px;padding:4px}
.node-btn{display:flex;align-items:center;gap:10px;padding:10px 12px;min-height:48px;border-radius:8px;border:1px solid var(--border);background:var(--surface);color:var(--text);font-family:var(--font);font-size:13px;cursor:pointer;transition:all 0.2s;text-align:left;width:100%}
.node-btn:hover{border-color:var(--node-color,var(--accent));background:var(--surface2)}
.node-btn[aria-selected=true]{border-color:var(--node-color,var(--accent));background:color-mix(in srgb,var(--node-color,var(--accent)) 12%,var(--surface))}
.node-btn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.node-indicator{width:4px;height:24px;border-radius:2px;background:var(--node-color,var(--accent));flex-shrink:0}
.node-name{font-weight:600;flex:1}
.node-cat{font-size:10px;color:var(--muted);text-transform:uppercase;letter-spacing:0.5px}
@media(max-width:768px){.node-list{flex-direction:row;flex-wrap:wrap;gap:4px}.node-btn{flex:1;min-width:120px;padding:8px 10px;font-size:12px}}
@media(max-width:480px){.node-btn{min-width:calc(50% - 4px);padding:6px 8px;font-size:11px}.node-cat{display:none}}
.info-panel{background:var(--surface);border-radius:12px;border:1px solid var(--border);padding:16px;min-height:200px;overflow-y:auto}
.info-placeholder{display:flex;align-items:center;justify-content:center;height:100%;min-height:180px;color:var(--muted);font-size:14px}
.info-title{font-size:18px;font-weight:700;margin-bottom:4px}
.info-section{margin-bottom:12px}
.info-section-label{font-size:11px;font-weight:600;color:var(--accent);text-transform:uppercase;letter-spacing:0.5px;margin-bottom:2px}
.info-section-text{font-size:13px;color:var(--text2);line-height:1.6}
.info-divider{height:1px;background:var(--border);margin:10px 0}
.section-title{font-size:18px;font-weight:700;margin-bottom:12px}
.challenge-container{display:flex;flex-direction:column;gap:14px;margin-bottom:14px}
.challenge-question{background:var(--surface);border-radius:12px;border:1px solid var(--border);padding:14px 16px}
.challenge-q-text{font-size:14px;font-weight:600;margin-bottom:10px}
.challenge-options{display:flex;flex-direction:column;gap:6px}
.challenge-option{display:flex;align-items:center;gap:10px;padding:8px 12px;min-height:44px;border-radius:6px;border:1px solid var(--border);background:var(--bg);cursor:pointer;font-size:13px;font-family:var(--font);color:var(--text)}
.challenge-option:hover{border-color:var(--accent)}
.challenge-option.selected{border-color:var(--accent);background:color-mix(in srgb,var(--accent) 10%,var(--bg))}
.challenge-option.correct{border-color:var(--accent2);background:color-mix(in srgb,var(--accent2) 10%,var(--bg))}
.challenge-option.incorrect{border-color:var(--danger);background:color-mix(in srgb,var(--danger) 10%,var(--bg))}
.challenge-option input[type=radio]{-webkit-appearance:none;appearance:none;width:18px;height:18px;border:2px solid var(--border);border-radius:50%;flex-shrink:0}
.challenge-option input[type=radio]:checked{border-color:var(--accent);background:var(--accent)}
.challenge-submit{width:100%}
.completion-overlay{position:fixed;inset:0;background:rgba(0,0,0,0.7);display:flex;align-items:center;justify-content:center;z-index:1000;padding:16px;backdrop-filter:blur(4px)}
.completion-card{background:var(--surface);border-radius:16px;padding:32px;text-align:center;max-width:360px;width:100%;border:1px solid var(--border);animation:popIn 0.3s ease-out}
@keyframes popIn{0%{transform:scale(0.9);opacity:0}100%{transform:scale(1);opacity:1}}
.completion-icon{font-size:48px;margin-bottom:8px}
.completion-title{font-size:22px;font-weight:700}
.completion-score{font-size:36px;font-weight:800;color:var(--accent);margin:8px 0}
.completion-msg{font-size:14px;color:var(--text2);margin-bottom:16px}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation-duration:0.01ms!important;animation-iteration-count:1!important;transition-duration:0.01ms!important}}