/* ===== DESIGN TOKENS ===== */
/* INITIATIVE-012C: AI Engineering OS design system */
:root,[data-theme="dark"]{
  --color-bg:#0e0f11;
  --color-surface:#141518;
  --color-surface-2:#1a1c20;
  --color-surface-offset:#1f2126;
  --color-surface-dynamic:#262930;
  --color-divider:#252830;
  --color-border:#2e323c;
  --color-text:#e2e4e9;
  --color-text-muted:#7c8393;
  --color-text-faint:#4a4f5e;
  --color-text-inverse:#0e0f11;
  --color-primary:#2dd4c0;
  --color-primary-hover:#1fbcaa;
  --color-primary-dim:rgba(45,212,192,0.10);
  --color-primary-glow:rgba(45,212,192,0.06);
  --color-basic:#6bbcf7;
  --color-intermediate:#a78bfa;
  --color-advanced:#f97066;
  --color-stable:#4ade80;
  --color-evolving:#fbbf24;
  --color-experimental:#fb923c;
  --radius-sm:0.25rem;
  --radius-md:0.5rem;
  --radius-lg:0.75rem;
  --radius-xl:1rem;
  --radius-full:9999px;
  --t:160ms cubic-bezier(0.16,1,0.3,1);
  --shadow-sm:0 1px 3px rgba(0,0,0,0.35);
  --shadow-md:0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg:0 12px 40px rgba(0,0,0,0.5);
  --topnav-h:52px;
  --sidebar-w:240px;
  --detail-w:340px;
  --text-xs:0.75rem;
  --text-sm:0.8125rem;
  --text-base:0.9375rem;
  --text-lg:1.0625rem;
  --text-xl:1.25rem;
  --font-body:'Inter','Helvetica Neue',sans-serif;
  --font-mono:'JetBrains Mono','Fira Code',monospace;
}
[data-theme="light"]{
  --color-bg:#f5f6f8;
  --color-surface:#ffffff;
  --color-surface-2:#f9fafb;
  --color-surface-offset:#f0f2f5;
  --color-surface-dynamic:#e8eaee;
  --color-divider:#e2e5ea;
  --color-border:#d4d8e0;
  --color-text:#1a1d24;
  --color-text-muted:#5a6070;
  --color-text-faint:#9aa0b0;
  --color-text-inverse:#ffffff;
  --color-primary:#0d9488;
  --color-primary-hover:#0b7a72;
  --color-primary-dim:rgba(13,148,136,0.10);
  --color-primary-glow:rgba(13,148,136,0.06);
  --shadow-sm:0 1px 3px rgba(0,0,0,0.08);
  --shadow-md:0 4px 16px rgba(0,0,0,0.10);
  --shadow-lg:0 12px 40px rgba(0,0,0,0.14);
}

*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{-webkit-font-smoothing:antialiased;scroll-behavior:smooth}
body{font-family:var(--font-body);font-size:var(--text-base);color:var(--color-text);background:var(--color-bg);min-height:100dvh;overflow-x:hidden}
img,svg{display:block}
button{cursor:pointer;background:none;border:none;color:inherit;font:inherit}
a{color:inherit;text-decoration:none}
a:focus-visible,button:focus-visible{outline:2px solid var(--color-primary);outline-offset:3px;border-radius:var(--radius-sm)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border-width:0}
.skip-link{position:absolute;top:-40px;left:1rem;padding:.5rem 1rem;background:var(--color-primary);color:var(--color-text-inverse);border-radius:var(--radius-md);z-index:9999;transition:top var(--t);font-size:var(--text-sm);font-weight:600}
.skip-link:focus{top:1rem}

.topnav{position:sticky;top:0;z-index:100;height:var(--topnav-h);background:var(--color-surface);border-bottom:1px solid var(--color-border)}
.topnav-inner{height:100%;padding:0 1.25rem;display:flex;align-items:center;justify-content:space-between;gap:1rem}
.brand{display:flex;align-items:center;gap:.625rem}
.brand-logo{width:24px;height:24px;color:var(--color-primary);flex-shrink:0}
.brand-name{font-size:var(--text-base);font-weight:600;letter-spacing:-.01em}
.brand-tag{font-size:var(--text-xs);font-weight:500;color:var(--color-text-muted);background:var(--color-surface-offset);padding:2px 8px;border-radius:var(--radius-full);border:1px solid var(--color-border)}
.topnav-links{display:flex;align-items:center;gap:.5rem}
.nav-link{display:flex;align-items:center;gap:.375rem;font-size:var(--text-sm);color:var(--color-text-muted);padding:.375rem .625rem;border-radius:var(--radius-md);transition:color var(--t),background var(--t);border:1px solid transparent}
.nav-link:hover{color:var(--color-text);background:var(--color-surface-offset)}
.theme-toggle{border:1px solid var(--color-border)!important}

/* HERO */
.hero{position:relative;padding:3.5rem 1.5rem 2.75rem;background:var(--color-surface);border-bottom:1px solid var(--color-border);overflow:hidden}
.hero-inner{position:relative;z-index:1;max-width:680px;margin:0 auto;text-align:center;display:flex;flex-direction:column;align-items:center;gap:1rem}
.hero-eyebrow{display:inline-flex;align-items:center;gap:.5rem;font-size:var(--text-xs);font-weight:600;letter-spacing:.1em;text-transform:uppercase;color:var(--color-primary);background:var(--color-primary-dim);padding:.25rem .875rem;border-radius:var(--radius-full);border:1px solid rgba(45,212,192,0.2)}
.hero-eyebrow-dot{width:6px;height:6px;border-radius:50%;background:var(--color-primary);animation:pulse-dot 2s ease-in-out infinite}
@keyframes pulse-dot{0%,100%{opacity:1;transform:scale(1)}50%{opacity:.5;transform:scale(.7)}}
.hero-title{font-size:clamp(1.75rem,4vw,3rem);font-weight:700;line-height:1.15;letter-spacing:-.03em;color:var(--color-text)}
.hero-accent{color:var(--color-primary)}
.hero-sub{font-size:var(--text-base);color:var(--color-text-muted);max-width:52ch;line-height:1.65}
.hero-stats{display:flex;align-items:center;background:var(--color-surface-offset);border:1px solid var(--color-border);border-radius:var(--radius-xl);overflow:hidden;margin-top:.5rem}
.hstat{display:flex;flex-direction:column;align-items:center;gap:2px;padding:.75rem 1.5rem}
.hstat-val{font-size:var(--text-xl);font-weight:700;letter-spacing:-.02em;color:var(--color-text);font-variant-numeric:tabular-nums}
.hstat-label{font-size:var(--text-xs);color:var(--color-text-muted);text-transform:uppercase;letter-spacing:.07em;font-weight:500}
.hstat-div{width:1px;height:36px;background:var(--color-divider);flex-shrink:0}
.hero-grid{position:absolute;inset:0;background-image:radial-gradient(circle,var(--color-border) 1px,transparent 1px);background-size:28px 28px;opacity:.35;pointer-events:none}

/* HEALTH BAR */
.health-bar{background:var(--color-surface-offset);border-bottom:1px solid var(--color-border);padding:.625rem 1.25rem}
.health-inner{display:flex;align-items:center;gap:1.25rem;overflow-x:auto;scrollbar-width:none;max-width:1400px;margin:0 auto}
.health-inner::-webkit-scrollbar{display:none}
.health-label{font-size:var(--text-xs);font-weight:700;text-transform:uppercase;letter-spacing:.1em;color:var(--color-text-faint);flex-shrink:0;white-space:nowrap}
.health-metrics{display:flex;align-items:center;flex:1}
.health-metric{display:flex;align-items:center;gap:.5rem;padding:.25rem .875rem;flex-shrink:0}
.health-metric-wide{flex:1;min-width:0}
.health-val{font-size:var(--text-sm);font-weight:700;color:var(--color-primary);font-variant-numeric:tabular-nums}
.health-val-sm{font-size:var(--text-xs);font-weight:600;color:var(--color-primary);white-space:nowrap;overflow:hidden;text-overflow:ellipsis;max-width:200px;display:inline-block}
.health-desc{font-size:var(--text-xs);color:var(--color-text-faint)}
.health-divider{width:1px;height:20px;background:var(--color-divider);flex-shrink:0}

/* LAYOUT */
.explorer-layout{display:grid;grid-template-columns:var(--sidebar-w) 1fr var(--detail-w);min-height:calc(100dvh - var(--topnav-h) - 109px)}

/* SIDEBAR */
.sidebar{border-right:1px solid var(--color-border);padding:1rem;display:flex;flex-direction:column;gap:1rem;position:sticky;top:var(--topnav-h);height:calc(100dvh - var(--topnav-h));overflow-y:auto;scrollbar-width:thin;scrollbar-color:var(--color-border) transparent;background:var(--color-surface)}
.search-box-wrap{position:relative;display:flex;align-items:center}
.search-icon{position:absolute;left:.625rem;color:var(--color-text-faint);pointer-events:none;flex-shrink:0}
.search-input{width:100%;padding:.5rem .625rem .5rem 2.125rem;background:var(--color-surface-offset);border:1px solid var(--color-border);border-radius:var(--radius-lg);font-size:var(--text-sm);color:var(--color-text);transition:border-color var(--t),background var(--t);outline:none}
.search-input:focus{border-color:var(--color-primary);background:var(--color-surface)}
.search-input::placeholder{color:var(--color-text-faint)}
.search-kbd{position:absolute;right:.625rem;font-size:10px;font-family:var(--font-mono);color:var(--color-text-faint);background:var(--color-surface-dynamic);border:1px solid var(--color-border);padding:1px 5px;border-radius:var(--radius-sm)}
.filter-group{display:flex;flex-direction:column;gap:.375rem}
.filter-label{font-size:var(--text-xs);font-weight:700;text-transform:uppercase;letter-spacing:.08em;color:var(--color-text-faint)}
.filter-chips{display:flex;flex-wrap:wrap;gap:.375rem}
.chip{font-size:var(--text-xs);padding:3px 10px;border-radius:var(--radius-full);border:1px solid var(--color-border);background:var(--color-surface-offset);color:var(--color-text-muted);transition:all var(--t);font-weight:500;white-space:nowrap}
.chip:hover{border-color:var(--color-primary);color:var(--color-primary)}
.chip-active{border-color:var(--color-primary);background:var(--color-primary-dim);color:var(--color-primary)!important}
.filter-chips-cats .chip{font-size:10px;padding:2px 8px}
.results-meta{font-size:var(--text-xs);color:var(--color-text-faint);padding-top:.25rem;margin-top:auto}

/* SKILL LIST */
.skill-list-panel{padding:1rem;overflow-y:auto;height:calc(100dvh - var(--topnav-h));background:var(--color-bg)}
.skill-grid{display:flex;flex-direction:column;gap:.375rem}
.skill-card{background:var(--color-surface);border:1px solid var(--color-border);border-radius:var(--radius-lg);padding:.75rem 1rem;cursor:pointer;transition:background var(--t),border-color var(--t),box-shadow var(--t),transform var(--t);display:flex;flex-direction:column;gap:.375rem}
.skill-card:hover{background:var(--color-surface-2);border-color:var(--color-primary);box-shadow:var(--shadow-sm)}
.skill-card.selected{border-color:var(--color-primary);background:var(--color-primary-glow);box-shadow:0 0 0 1px var(--color-primary)}
.skill-card:active{transform:scale(.99)}
.skill-card-title{font-size:var(--text-sm);font-weight:600;color:var(--color-text);line-height:1.3}
.skill-card-row{display:flex;align-items:center;gap:.5rem;flex-wrap:wrap}
.skill-card-id{font-family:var(--font-mono);font-size:10px;color:var(--color-text-faint)}
.skill-card-cat{font-size:10px;color:var(--color-text-faint);background:var(--color-surface-offset);padding:1px 6px;border-radius:var(--radius-full);border:1px solid var(--color-border)}
.skill-card-reqby{font-size:10px;font-weight:700;color:var(--color-primary);background:var(--color-primary-dim);padding:1px 6px;border-radius:var(--radius-full);border:1px solid rgba(45,212,192,0.2);margin-left:auto;white-space:nowrap}

/* BADGES */
.badge{display:inline-flex;align-items:center;font-size:10px;font-weight:600;padding:2px 7px;border-radius:var(--radius-full);letter-spacing:.04em}
.badge-level-basic{color:var(--color-basic);background:rgba(107,188,247,0.12)}
.badge-level-intermediate{color:var(--color-intermediate);background:rgba(167,139,250,0.12)}
.badge-level-advanced{color:var(--color-advanced);background:rgba(249,112,102,0.12)}
.badge-stable{color:var(--color-stable);background:rgba(74,222,128,0.10)}
.badge-evolving{color:var(--color-evolving);background:rgba(251,191,36,0.10)}
.badge-experimental{color:var(--color-experimental);background:rgba(251,146,60,0.10)}

/* SKELETON */
@keyframes shimmer{0%{background-position:-200% 0}100%{background-position:200% 0}}
.skeleton{pointer-events:none}
.skeleton-line{height:12px;border-radius:var(--radius-sm);margin-bottom:8px;background:linear-gradient(90deg,var(--color-surface-offset) 25%,var(--color-surface-dynamic) 50%,var(--color-surface-offset) 75%);background-size:200% 100%;animation:shimmer 1.4s ease-in-out infinite}

/* DETAIL PANEL */
.detail-panel{border-left:1px solid var(--color-border);background:var(--color-surface);position:sticky;top:var(--topnav-h);height:calc(100dvh - var(--topnav-h));overflow-y:auto;scrollbar-width:thin;scrollbar-color:var(--color-border) transparent}
.detail-empty{display:flex;flex-direction:column;align-items:center;justify-content:center;height:100%;gap:1rem;color:var(--color-text-faint);text-align:center;font-size:var(--text-sm);line-height:1.6;padding:2rem}
.detail-content{padding:1.25rem;display:flex;flex-direction:column;gap:1.25rem}
.detail-header{display:flex;flex-direction:column;gap:.5rem}
.detail-header-top{display:flex;align-items:center;justify-content:space-between}
.detail-cat-badge{font-size:var(--text-xs);font-weight:600;color:var(--color-primary);background:var(--color-primary-dim);padding:2px 10px;border-radius:var(--radius-full);border:1px solid rgba(45,212,192,0.2)}
.detail-actions{display:flex;gap:.375rem}
.icon-btn{display:flex;align-items:center;justify-content:center;width:30px;height:30px;border-radius:var(--radius-md);border:1px solid var(--color-border);color:var(--color-text-muted);transition:all var(--t)}
.icon-btn:hover{color:var(--color-text);border-color:var(--color-text-faint);background:var(--color-surface-offset)}
.detail-title{font-size:var(--text-lg);font-weight:700;color:var(--color-text);line-height:1.25;letter-spacing:-.01em}
.detail-id{font-family:var(--font-mono);font-size:11px;color:var(--color-primary);background:var(--color-primary-dim);padding:3px 8px;border-radius:var(--radius-sm);display:inline-block}
.detail-tags-row{display:flex;flex-wrap:wrap;gap:.375rem}
.detail-tags-row .tag:empty{display:none}
.tag{font-size:10px;font-weight:600;padding:3px 9px;border-radius:var(--radius-full);background:var(--color-surface-offset);color:var(--color-text-muted);letter-spacing:.04em}
.detail-meta{display:flex;flex-direction:column;gap:.375rem;padding:.75rem;background:var(--color-surface-offset);border-radius:var(--radius-lg);border:1px solid var(--color-border)}
.meta-row{display:flex;gap:.75rem;align-items:baseline;font-size:var(--text-xs)}
.meta-row dt{color:var(--color-text-faint);font-weight:600;text-transform:uppercase;letter-spacing:.06em;min-width:50px;flex-shrink:0}
.meta-row dd{color:var(--color-text-muted)}
.mono-small{font-family:var(--font-mono);font-size:10px;word-break:break-all}

/* DEP SECTIONS */
.detail-section{display:flex;flex-direction:column;gap:.5rem}
.detail-section-title{font-size:var(--text-xs);font-weight:700;color:var(--color-text-faint);text-transform:uppercase;letter-spacing:.08em;display:flex;align-items:center;gap:.375rem}
.dep-list{display:flex;flex-direction:column;gap:.25rem}
.dep-item{font-size:var(--text-xs);color:var(--color-primary);cursor:pointer;padding:5px 8px;border-radius:var(--radius-sm);border:1px solid transparent;transition:all var(--t);display:flex;align-items:center;gap:.375rem;background:var(--color-surface-offset)}
.dep-item:hover{background:var(--color-primary-dim);border-color:var(--color-primary)}
.dep-item:focus-visible{outline:2px solid var(--color-primary);outline-offset:2px}
.dep-item:active{transform:scale(.98)}
.dep-arrow{flex-shrink:0;color:var(--color-text-faint);transition:transform var(--t),color var(--t)}
.dep-item:hover .dep-arrow{color:var(--color-primary);transform:translateX(2px)}
.dep-label{flex:1;min-width:0;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-weight:500}
.dep-cat{font-size:9px;color:var(--color-text-faint);background:var(--color-surface-dynamic);padding:1px 6px;border-radius:var(--radius-full);border:1px solid var(--color-border);flex-shrink:0;white-space:nowrap}
.dep-empty{font-size:var(--text-xs);color:var(--color-text-faint);font-style:italic;padding:4px 2px;line-height:1.5}

/* TOAST */
.toast{position:fixed;bottom:1.5rem;left:50%;transform:translateX(-50%) translateY(120%);background:var(--color-surface-dynamic);color:var(--color-text);border:1px solid var(--color-border);padding:.625rem 1.25rem;border-radius:var(--radius-full);font-size:var(--text-sm);font-weight:500;box-shadow:var(--shadow-lg);transition:transform var(--t);z-index:9000;white-space:nowrap;pointer-events:none}
.toast.show{transform:translateX(-50%) translateY(0)}

/* EMPTY STATE */
.mobile-overlay{display:none}
.empty-state{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:4rem 2rem;gap:1rem;color:var(--color-text-faint);text-align:center}
.empty-state svg{opacity:.5}
.empty-state-title{font-size:var(--text-base);font-weight:600;color:var(--color-text-muted)}
.empty-state p{font-size:var(--text-sm);max-width:32ch;line-height:1.6}
.empty-state code{font-family:var(--font-mono);font-size:var(--text-xs);background:var(--color-surface-offset);padding:2px 6px;border-radius:var(--radius-sm);border:1px solid var(--color-border);word-break:break-all}

/* SCROLLBARS */
*{scrollbar-width:thin;scrollbar-color:var(--color-border) transparent}
::-webkit-scrollbar{width:6px;height:6px}
::-webkit-scrollbar-track{background:transparent}
::-webkit-scrollbar-thumb{background:var(--color-border);border-radius:3px}

mark{background:var(--color-primary-dim);color:var(--color-primary);border-radius:2px;padding:0 1px}
::selection{background:var(--color-primary-dim);color:var(--color-text)}

/* RESPONSIVE */
@media(max-width:1100px){:root{--detail-w:280px}}
@media(max-width:900px){
  .explorer-layout{grid-template-columns:var(--sidebar-w) 1fr}
  .detail-panel{display:none}
  .mobile-overlay{display:flex;flex-direction:column;position:fixed;inset:0;z-index:500;background:var(--color-surface);overflow-y:auto}
  .mobile-overlay[hidden]{display:none!important}
  .mobile-overlay-header{display:flex;align-items:center;justify-content:space-between;padding:1rem 1.25rem;border-bottom:1px solid var(--color-border);position:sticky;top:0;background:var(--color-surface)}
  .mobile-overlay-title{font-size:var(--text-lg);font-weight:700}
  #mobile-overlay-body{padding:1.25rem}
  .hero{padding:2rem 1.25rem 1.75rem}
  .hero-stats{flex-wrap:wrap}
  .hstat{padding:.625rem 1rem}
}
@media(max-width:640px){
  :root{--sidebar-w:100%}
  .explorer-layout{grid-template-columns:1fr}
  .sidebar{position:static;height:auto}
  .skill-list-panel{min-height:60dvh}
  .hero-title{font-size:1.75rem}
  .hstat-div{display:none}
  .hstat{border-bottom:1px solid var(--color-divider);width:50%}
}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{animation-duration:.01ms!important;transition-duration:.01ms!important}}