:root{--bg: #070b16;--bg-2: #0c1324;--surface: #111a2e;--surface-2: #18233c;--line: rgba(6, 182, 212, .18);--text: #e8eefc;--muted: #93a4c7;--cyan: #06b6d4;--blue: #3b82f6;--navy: #1e3a8a;--ok: #34d399;--warn: #fbbf24;--bad: #fb7185;--shadow: 0 18px 50px rgba(0, 0, 0, .35);--radius: 18px;--font: "IBM Plex Sans", "Readex Pro", system-ui, sans-serif;--mono: "IBM Plex Mono", ui-monospace, monospace}[lang=ar]{--font: "Readex Pro", "IBM Plex Sans", system-ui, sans-serif}*{box-sizing:border-box}html,body{margin:0;min-height:100%}body{font-family:var(--font);background:radial-gradient(1200px 500px at 10% -10%,rgba(6,182,212,.12),transparent 50%),radial-gradient(900px 400px at 100% 0%,rgba(30,58,138,.35),transparent 45%),var(--bg);color:var(--text);line-height:1.65}a{color:var(--cyan);text-decoration:none}a:hover{text-decoration:underline}img{max-width:100%}button,input,select{font-family:inherit}.app-shell{min-height:100vh;display:flex;flex-direction:column}.wrap{width:min(1120px,calc(100% - 32px));margin:0 auto}.site-header{position:sticky;top:0;z-index:20;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px);background:#070b16c7;border-bottom:1px solid var(--line)}.header-inner{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:14px 0}.brand{display:flex;align-items:center;gap:10px;color:var(--text);font-weight:700;letter-spacing:.01em;text-decoration:none}.brand:hover{text-decoration:none;color:var(--cyan)}.brand-mark{width:36px;height:36px}.nav{display:flex;align-items:center;gap:8px;flex-wrap:wrap;justify-content:flex-end}.nav a{color:var(--muted);padding:8px 12px;border-radius:999px;text-decoration:none;font-weight:500}.nav a.router-link-active,.nav a:hover{color:var(--text);background:#06b6d41f}.lang-btn,.ghost-btn,.primary-btn,.icon-btn{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:999px;padding:8px 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var(--line);border-radius:var(--radius);padding:22px;box-shadow:var(--shadow)}.bars{display:flex;align-items:flex-end;gap:8px;height:160px}.bars span{flex:1;border-radius:8px 8px 4px 4px;background:linear-gradient(180deg,var(--cyan),var(--navy));min-width:10px}.grid-3,.grid-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:18px}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:20px;box-shadow:0 10px 30px #0000002e}.card h3{margin-top:8px}.muted{color:var(--muted)}.section-head{margin:42px 0 18px}.lesson-list{display:grid;gap:12px}.lesson-row{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:16px 18px;border:1px solid var(--line);border-radius:14px;background:var(--surface);color:inherit;text-decoration:none}.lesson-row:hover{border-color:var(--cyan);text-decoration:none}.badge{display:inline-block;font-size:.75rem;padding:3px 8px;border-radius:999px;background:#06b6d41f;color:var(--cyan);font-weight:600}.badge.done{background:#34d39924;color:var(--ok)}.article h2{margin-top:28px}.article p,.article li{color:var(--text)}.article code,.code-block{font-family:var(--mono);font-size:.92rem}.article code{background:var(--surface-2);padding:1px 6px;border-radius:6px}.code-block{background:#08101f;border:1px solid var(--line);border-radius:14px;padding:16px 18px;overflow:auto;color:#dbeafe;line-height:1.7;margin:16px 0 24px;direction:ltr;unicode-bidi:isolate;text-align:left;font-family:var(--mono)}.code-comment{color:#86efac;font-style:italic;unicode-bidi:isolate}.step-body code,.article code,.lead code,p code,li code{direction:ltr;unicode-bidi:isolate;display:inline-block;font-family:var(--mono);text-align:left}.quiz{margin-top:28px;border:1px solid var(--line);border-radius:16px;padding:18px;background:var(--bg-2)}.option{display:flex;gap:10px;align-items:flex-start;padding:10px 12px;border-radius:10px;cursor:pointer;border:1px solid transparent}.option:hover{background:var(--surface)}.option.picked{border-color:var(--cyan);background:#06b6d414}.option.good{border-color:var(--ok)}.option.bad{border-color:var(--bad)}.feedback{margin-top:10px;font-weight:600}.feedback.ok{color:var(--ok)}.feedback.no{color:var(--warn)}.pager{display:flex;justify-content:space-between;gap:12px;margin-top:32px;flex-wrap:wrap}.lesson-shell{width:min(760px,100%);margin:0 auto}.deck-page{width:min(1080px,calc(100% - 24px))}.deck-toolbar{display:flex;align-items:center;justify-content:space-between;gap:12px;margin-bottom:14px;flex-wrap:wrap}.deck-title{font-weight:700;color:var(--muted);flex:1;text-align:center}.slide-stage{perspective:1200px}.slide{position:relative;min-height:min(62vh,640px);background:linear-gradient(180deg,rgba(6,182,212,.06),transparent 28%),linear-gradient(135deg,#0b1630,#111a2e 48%,#0a1022);border:1px solid var(--line);border-radius:4px 4px 18px 18px;padding:28px 32px 18px;box-shadow:0 0 0 1px #ffffff0a,0 24px 60px #00000073;display:flex;flex-direction:column;animation:slide-in .45s ease;overflow:hidden}@keyframes slide-in{0%{opacity:0;transform:translateY(12px) scale(.985)}to{opacity:1;transform:none}}.slide-accent{position:absolute;top:0;left:0;right:0;height:5px;background:linear-gradient(90deg,var(--cyan),var(--blue),var(--navy))}.slide-kicker{margin:8px 0 6px;letter-spacing:.14em;text-transform:uppercase;font-size:.72rem;color:var(--cyan);font-weight:700}.slide-heading{font-size:clamp(1.6rem,3.4vw,2.35rem);letter-spacing:-.03em;margin:0 0 14px}.slide-body{flex:1;font-size:1.12rem}.teacher{display:flex;gap:12px;align-items:flex-start;margin-top:18px;padding:12px 14px;background:#06b6d414;border:1px solid var(--line);border-radius:14px}.teacher-face{width:44px;height:44px;border-radius:50%;flex-shrink:0;display:grid;place-items:center;font-weight:800;color:#041018;background:linear-gradient(135deg,var(--cyan),var(--blue));box-shadow:0 0 0 3px #06b6d433}.teacher-label{margin:0 0 4px;font-size:.72rem;letter-spacing:.08em;text-transform:uppercase;color:var(--cyan);font-weight:700}.teacher-words{font-size:.95rem;color:#dbeafe;line-height:1.55}.teacher-words p{margin:0}.player{display:flex;align-items:center;gap:8px;margin-top:14px;padding:10px 12px;background:#070b16;border:1px solid var(--line);border-radius:999px;flex-wrap:wrap}.player-btn{border:0;background:var(--surface-2);color:var(--text);border-radius:999px;min-width:40px;height:40px;font-weight:700;cursor:pointer}.player-btn:disabled{opacity:.35;cursor:not-allowed}.player-play{background:linear-gradient(135deg,var(--cyan),var(--navy));padding:0 16px;min-width:132px}.player-speed{display:flex;align-items:center;gap:6px;color:var(--muted);font-size:.82rem;font-weight:600;white-space:nowrap}.player-speed select{background:var(--surface-2);color:var(--text);border:1px solid var(--line);border-radius:999px;padding:6px 10px;font-weight:600;cursor:pointer}.player-bar{flex:1;min-width:80px;height:6px;background:var(--surface-2);border-radius:99px;overflow:hidden}.player-bar>span{display:block;height:100%;background:linear-gradient(90deg,var(--cyan),var(--blue))}.player-time{font-family:var(--mono);font-size:.85rem;color:var(--muted);padding-inline:6px}.player-hint{color:var(--muted);font-size:.85rem;margin:10px 4px 0;text-align:center}.back-link{font-weight:600}.step-meta{display:flex;align-items:center;justify-content:space-between;gap:12px;margin:18px 0 10px}.step-bar{height:6px;background:var(--surface-2);border-radius:99px;overflow:hidden;margin-bottom:18px}.step-bar>span{display:block;height:100%;background:linear-gradient(90deg,var(--cyan),var(--blue));transition:width .25s ease}.step-card{min-height:280px;background:var(--surface);border:1px solid var(--line);border-radius:20px;padding:28px 26px 32px;box-shadow:var(--shadow)}.step-card h1{font-size:clamp(1.45rem,3vw,2rem)}.step-body{font-size:1.08rem}.step-body p:first-child,.step-body ul:first-child,.step-body ol:first-child{margin-top:0}.step-nav{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-top:20px}.step-nav .ghost-btn:disabled{opacity:.35;cursor:not-allowed}.quiz.plain{margin-top:0;border:none;padding:0;background:transparent}.quiz.plain h3{display:none}.tw-caret{display:inline-block;width:2px;height:1em;margin-inline-start:2px;background:var(--cyan);vertical-align:-.15em;animation:tw-blink .85s step-end infinite}@keyframes tw-blink{50%{opacity:0}}.tw-hint{margin:16px 0 0;color:var(--muted);font-size:.85rem}.code-wrap .code-block{margin:0}.step-card .lead{margin-top:0}.viz{margin:20px 0 8px;padding:18px;border-radius:16px;border:1px solid var(--line);background:var(--surface);direction:ltr;unicode-bidi:isolate;text-align:left}.viz-bars{display:flex;align-items:flex-end;gap:6px;height:180px;margin:12px 0 16px}.viz-bars .bar{flex:1;border-radius:6px 6px 2px 2px;background:#334155;position:relative;min-width:8px;transition:height .15s ease,background .15s ease,transform .15s ease}.viz-bars .bar b{position:absolute;inset-inline:0;top:-22px;text-align:center;font-size:.72rem;color:var(--muted);font-family:var(--mono)}.viz-bars .bar.compare{background:var(--warn)}.viz-bars .bar.swap{background:var(--cyan)}.viz-bars .bar.pivot{background:var(--blue)}.viz-bars .bar.done{background:var(--ok)}.viz-bars .bar.target{outline:2px solid var(--cyan)}.viz-controls{display:flex;flex-wrap:wrap;gap:8px;align-items:center}.status-line{min-height:1.5em;color:var(--muted);font-family:var(--mono);font-size:.9rem;margin:8px 0 0}.site-footer{border-top:1px solid var(--line);padding:22px 0;color:var(--muted);font-size:.92rem}.footer-inner{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap}.menu-toggle{display:none}@media (max-width: 860px){.hero,.grid-3,.grid-cards{grid-template-columns:1fr}.menu-toggle{display:inline-flex}.nav{display:none}.nav.open{display:flex;position:absolute;inset-inline:16px;top:64px;background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:10px;flex-direction:column;align-items:stretch}}