@font-face {
  font-family: "Qomra";
  src: url("fonts/qomra.ttf") format("truetype");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}
:root {
  --navy-950:#041426;--navy-900:#061d35;--navy-800:#0a2a49;--navy-700:#0d3b61;
  --blue:#1677c8;--cyan:#22c7d8;--cyan-soft:#dffaff;--pink:#e74493;--orange:#ff9b42;
  --green:#26b983;--purple:#8a5bd4;--ink:#0b2742;--muted:#52677a;--line:#dbe7ef;
  --paper:#f4f8fb;--white:#fff;--shadow:0 22px 70px rgba(7,37,65,.12);--shadow-soft:0 12px 32px rgba(7,37,65,.08);
  --radius-lg:28px;--radius-md:20px;--radius-sm:14px;
}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:88px}body{margin:0;min-width:320px;overflow-x:hidden;color:var(--ink);background:var(--paper);font-family:"Qomra",Tahoma,"Segoe UI",Arial,sans-serif;line-height:1.8}body.motion-paused *{animation-play-state:paused!important}button,input,a{font:inherit}button{border:0}a{color:inherit;text-decoration:none}::selection{background:rgba(34,199,216,.28);color:var(--navy-950)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}
.ambient{position:fixed;z-index:-3;width:620px;height:620px;border-radius:50%;filter:blur(110px);opacity:.22;pointer-events:none}.ambient-a{top:-280px;right:-220px;background:var(--cyan)}.ambient-b{left:-260px;top:42vh;background:var(--pink);opacity:.12}.noise{display:none}
.topbar{position:fixed;inset:0 0 auto;z-index:50;display:flex;align-items:center;justify-content:space-between;min-height:76px;padding:11px clamp(18px,4vw,62px);border-bottom:1px solid rgba(255,255,255,.09);color:white;background:rgba(4,20,38,.78);backdrop-filter:blur(18px) saturate(145%);transition:.3s}.topbar.scrolled{background:rgba(4,20,38,.95);box-shadow:0 10px 30px rgba(0,0,0,.14)}.brand{display:flex;align-items:center;gap:12px}.brand-mark{display:grid;place-items:center;width:46px;height:46px;color:var(--cyan);border:1px solid rgba(34,199,216,.38);border-radius:15px;background:linear-gradient(145deg,rgba(34,199,216,.16),rgba(255,255,255,.04))}.brand-mark svg{width:29px}.brand-copy{display:flex;flex-direction:column;line-height:1.25}.brand-copy strong{font-size:.98rem;font-weight:900}.brand-copy small{margin-top:4px;color:#a8c3d8;font-size:.72rem}.desktop-nav{display:flex;align-items:center;gap:20px;color:#c5d5e3;font-size:.88rem}.desktop-nav a{position:relative;transition:color .2s}.desktop-nav a:after{content:"";position:absolute;right:0;bottom:-8px;width:0;height:2px;border-radius:2px;background:var(--cyan);transition:width .2s}.desktop-nav a:hover{color:white}.desktop-nav a:hover:after{width:100%}.header-actions{display:flex;gap:8px}.icon-button{display:grid;place-items:center;width:42px;height:42px;color:#d9e8f3;border:1px solid rgba(255,255,255,.12);border-radius:13px;background:rgba(255,255,255,.06);cursor:pointer;transition:.2s}.icon-button:hover{transform:translateY(-2px);background:rgba(255,255,255,.12)}.icon-button svg{width:21px}.play-icon{display:none}body.motion-paused .pause-icon{display:none}body.motion-paused .play-icon{display:block}.reading-progress{position:fixed;z-index:51;top:0;right:0;left:0;height:3px}.reading-progress span{display:block;width:0;height:100%;background:linear-gradient(90deg,var(--pink),var(--cyan));box-shadow:0 0 14px rgba(34,199,216,.6)}
.mobile-nav-toggle,.mobile-nav,.mobile-stage-toggle{display:none}.mobile-nav-toggle{width:44px;height:44px;padding:10px;color:#fff;border:1px solid rgba(255,255,255,.14);border-radius:13px;background:rgba(255,255,255,.06);cursor:pointer}.mobile-nav-toggle span{display:block;height:2px;margin:5px 0;border-radius:2px;background:currentColor}.mobile-nav{position:fixed;z-index:49;top:76px;right:14px;left:14px;grid-template-columns:repeat(2,1fr);gap:8px;padding:12px;border:1px solid rgba(255,255,255,.12);border-radius:0 0 18px 18px;color:#d8e9f4;background:rgba(4,20,38,.97);box-shadow:0 18px 38px rgba(0,0,0,.22)}.mobile-nav a{min-height:44px;padding:9px 12px;border:1px solid rgba(255,255,255,.08);border-radius:11px;background:rgba(255,255,255,.05);font-size:.82rem;font-weight:800}.mobile-stage-toggle{position:absolute;z-index:28;top:16px;left:20px;min-height:44px;padding:0 13px;color:#fff;border:1px solid rgba(255,255,255,.15);border-radius:12px;background:rgba(4,20,38,.82);cursor:pointer;font-size:.74rem;font-weight:900}
.section-rail{position:fixed;z-index:40;top:50%;left:16px;display:flex;flex-direction:column;gap:2px;transform:translateY(-50%)}.section-rail a{position:relative;display:grid;place-items:center;width:26px;height:26px;border-radius:50%}.section-rail a:before{content:"";width:9px;height:9px;border:1px solid rgba(8,48,78,.32);border-radius:50%;background:#fff;transition:.2s}.section-rail a:after{content:attr(data-label);position:absolute;top:50%;left:30px;width:max-content;padding:6px 9px;color:#fff;border-radius:8px;background:var(--navy-900);font-size:.72rem;opacity:0;pointer-events:none;transform:translateY(-50%) translateX(-6px);transition:.2s}.section-rail a:hover:after,.section-rail a:focus-visible:after{opacity:1;transform:translateY(-50%) translateX(0)}.section-rail a.active:before{width:11px;height:11px;border-color:var(--cyan);background:var(--cyan);box-shadow:0 0 0 6px rgba(34,199,216,.13)}
.hero{position:relative;display:grid;grid-template-columns:minmax(0,.9fr) minmax(480px,1.1fr);align-items:center;min-height:100vh;padding:120px clamp(24px,6vw,90px) 62px;color:#fff;background:radial-gradient(circle at 80% 18%,rgba(34,199,216,.19),transparent 28%),radial-gradient(circle at 10% 70%,rgba(138,91,212,.14),transparent 24%),linear-gradient(135deg,#041426,#072a49 58%,#061d35)}.hero:after{content:"";position:absolute;inset:auto 0 0;height:160px;background:linear-gradient(transparent,rgba(244,248,251,.08));pointer-events:none}.hero-copy{position:relative;z-index:2;max-width:660px}.eyebrow{display:flex;align-items:center;gap:9px;color:var(--cyan);font-size:.84rem;font-weight:800;letter-spacing:.03em}.eyebrow span{width:28px;height:2px;border-radius:2px;background:currentColor}.hero h1,.lesson-card h2{margin:16px 0 18px;line-height:1.08;letter-spacing:-.04em;font-weight:900}.hero h1{font-size:clamp(3.7rem,8vw,7.4rem)}.hero h1 em,.lesson-card h2 em{color:var(--cyan);font-style:normal}.hero-lead{max-width:590px;margin:0;color:#c5d9e7;font-size:clamp(1.08rem,1.8vw,1.35rem);line-height:1.9}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:30px}.primary-button,.ghost-button{display:inline-flex;align-items:center;justify-content:center;gap:10px;min-height:50px;padding:0 22px;border-radius:15px;font-weight:800;cursor:pointer;transition:.2s}.primary-button{color:var(--navy-950);background:linear-gradient(135deg,#72e2ed,var(--cyan));box-shadow:0 12px 30px rgba(34,199,216,.2)}.primary-button:hover{transform:translateY(-3px);box-shadow:0 16px 38px rgba(34,199,216,.31)}.ghost-button{color:#fff;border:1px solid rgba(255,255,255,.2);background:rgba(255,255,255,.06)}.ghost-button:hover{transform:translateY(-3px);background:rgba(255,255,255,.11)}.ghost-button.dark{color:var(--navy-800);border-color:var(--line);background:white}.small{min-height:42px;padding:0 17px;font-size:.84rem}.hero-stat-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;max-width:560px;margin-top:34px}.hero-stat-grid div{padding:14px 16px;border:1px solid rgba(255,255,255,.1);border-radius:16px;background:rgba(255,255,255,.045);backdrop-filter:blur(8px)}.hero-stat-grid strong{display:block;color:#fff;font-size:1.45rem;line-height:1.2}.hero-stat-grid span{color:#9eb8cb;font-size:.75rem}.hero-visual{position:relative;z-index:2;min-width:0}
.stage-shell{position:relative;overflow:hidden;width:100%;min-height:520px;border:1px solid rgba(123,224,236,.22);border-radius:32px;background:linear-gradient(150deg,rgba(255,255,255,.08),rgba(255,255,255,.02)),#071b31;box-shadow:0 35px 90px rgba(0,0,0,.25),inset 0 1px 0 rgba(255,255,255,.12);isolation:isolate}.hero-stage-shell{transform:perspective(1200px) rotateY(-3deg) rotateX(1deg);transform-origin:center}#solidCanvas{position:absolute;inset:0;width:100%;height:100%;z-index:2;touch-action:pan-y}.stage-vignette{position:absolute;inset:0;z-index:3;pointer-events:none;background:radial-gradient(circle at center,transparent 45%,rgba(3,16,29,.42) 100%)}.stage-grid{position:absolute;inset:0;z-index:1;opacity:.17;background-image:linear-gradient(rgba(104,219,233,.14) 1px,transparent 1px),linear-gradient(90deg,rgba(104,219,233,.14) 1px,transparent 1px);background-size:42px 42px;mask-image:linear-gradient(to bottom,transparent,#000 25%,#000 75%,transparent)}.stage-hud{position:absolute;z-index:5;top:22px;right:22px;left:158px;display:flex;align-items:flex-start;justify-content:space-between;pointer-events:none}.stage-hud>div:first-child{display:flex;flex-direction:column}.stage-hud span{color:#8fc2d8;font-size:.73rem}.stage-hud strong{margin-top:4px;color:#fff;font-size:1.22rem}.hud-metrics{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.hud-metrics span{display:flex;align-items:center;gap:6px;padding:7px 10px;color:#cde7f0;border:1px solid rgba(255,255,255,.1);border-radius:999px;background:rgba(4,20,38,.42);backdrop-filter:blur(8px)}.hud-metrics i{width:6px;height:6px;border-radius:50%;background:var(--cyan);box-shadow:0 0 10px currentColor}.canvas-hint{position:absolute;z-index:5;right:22px;bottom:20px;display:flex;align-items:center;gap:8px;color:#86a6ba;font-size:.72rem;pointer-events:none}.canvas-hint span{width:18px;height:18px;border:1px solid rgba(255,255,255,.25);border-radius:50%}.stage-bottom{position:absolute;z-index:5;right:20px;left:20px;bottom:20px;display:flex;gap:8px;justify-content:center;pointer-events:none}.live-metric{min-width:110px;padding:8px 11px;border:1px solid rgba(255,255,255,.09);border-radius:12px;background:rgba(4,20,38,.52);backdrop-filter:blur(8px);text-align:center}.live-metric span{display:block;color:#8fb1c4;font-size:.63rem}.live-metric strong{display:block;color:#fff;font-size:.78rem}
.stage-tool{position:absolute;z-index:8;left:22px;top:22px;display:flex;align-items:center;gap:7px;min-height:42px;padding:0 12px;color:#d8f4f8;border:1px solid rgba(255,255,255,.13);border-radius:12px;background:rgba(4,20,38,.55);backdrop-filter:blur(8px);cursor:pointer;font-size:.72rem;font-weight:800}.stage-tool:hover{background:rgba(20,82,108,.75)}.stage-tool svg{width:18px}.stage-shell:fullscreen,.stage-shell.pseudo-fullscreen{width:100vw;height:100vh;min-height:100vh;border:0;border-radius:0;transform:none}.stage-shell.pseudo-fullscreen{position:fixed;z-index:100;inset:0}.stage-shell:fullscreen .stage-tool,.stage-shell.pseudo-fullscreen .stage-tool,.stage-shell.fs-with-controls .stage-tool{top:14px;left:18px;z-index:10}
.lesson-layout{display:grid;grid-template-columns:minmax(390px,42vw) minmax(0,1fr);align-items:start;gap:0;max-width:1600px;margin:auto}.sticky-stage{position:sticky;top:86px;height:calc(100vh - 86px);padding:26px 0 26px 26px;direction:ltr}.sticky-stage .stage-shell{height:100%;min-height:0;transform:none;border-radius:26px}.lesson-content{min-width:0}.content-section{position:relative;min-height:95vh;padding:88px clamp(22px,4vw,60px)}.content-section:nth-child(odd){background:rgba(255,255,255,.62)}.lesson-card{position:relative;overflow:hidden;padding:clamp(26px,4vw,52px);border:1px solid rgba(12,63,99,.1);border-radius:var(--radius-lg);background:rgba(255,255,255,.94);box-shadow:var(--shadow);backdrop-filter:blur(12px)}.lesson-card:before{content:"";position:absolute;inset:0 0 auto;height:5px;background:linear-gradient(90deg,var(--blue),var(--cyan),var(--purple))}.section-number{position:absolute;left:24px;top:18px;color:rgba(11,39,66,.07);font-size:clamp(4.8rem,9vw,8rem);font-weight:900;line-height:1;pointer-events:none}.section-tag{display:inline-flex;padding:6px 11px;border-radius:999px;color:var(--blue);background:#e9f5ff;font-size:.72rem;font-weight:900}.section-tag.pink{color:var(--pink);background:#fff0f7}.section-tag.green{color:var(--green);background:#eafaf4}.section-tag.blue{color:var(--blue);background:#edf6ff}.section-tag.orange{color:#b7650b;background:#fff4e5}.section-tag.purple{color:var(--purple);background:#f4efff}.lesson-card h2{position:relative;max-width:720px;font-size:clamp(2.2rem,4vw,4rem);color:var(--navy-900)}.section-intro{position:relative;margin:0 0 30px;color:var(--muted);font-size:1.04rem;line-height:2}
.concept-grid{display:grid;gap:14px;margin:26px 0}.concept-grid.three{grid-template-columns:repeat(3,1fr)}.concept-card{min-height:205px;padding:22px;border:1px solid var(--line);border-radius:20px;background:linear-gradient(145deg,#fff,#f3f9fc);box-shadow:var(--shadow-soft)}.concept-card h3{margin:15px 0 8px;color:var(--navy-800);font-size:1.05rem}.concept-card p{margin:0;color:var(--muted);font-size:.85rem;line-height:1.8}.concept-icon{position:relative;display:block;width:48px;height:48px;border-radius:14px;background:var(--cyan-soft)}.vibrate-icon:before{content:"〰";position:absolute;inset:0;display:grid;place-items:center;color:var(--blue);font-size:1.6rem;font-weight:900}.fixed-icon:before{content:"▣";position:absolute;inset:0;display:grid;place-items:center;color:var(--green);font-size:1.5rem}.melt-icon:before{content:"°C";position:absolute;inset:0;display:grid;place-items:center;color:var(--orange);font-size:1.05rem;font-weight:900;direction:ltr}.iodine-icon:before{content:"I—I";position:absolute;inset:0;display:grid;place-items:center;color:var(--purple);font-size:.9rem;font-weight:900;direction:ltr}.ice-icon:before{content:"H···O";position:absolute;inset:0;display:grid;place-items:center;color:var(--blue);font-size:.82rem;font-weight:900;direction:ltr}.bucky-icon:before{content:"C₆₀";position:absolute;inset:0;display:grid;place-items:center;color:var(--pink);font-size:.95rem;font-weight:900;direction:ltr}.diamond-icon:before{content:"◇";position:absolute;inset:0;display:grid;place-items:center;color:var(--cyan);font-size:1.7rem;font-weight:900}.graphite-icon:before{content:"⬡";position:absolute;inset:0;display:grid;place-items:center;color:var(--navy-800);font-size:1.6rem}.quartz-icon:before{content:"SiO₂";position:absolute;inset:0;display:grid;place-items:center;color:var(--orange);font-size:.82rem;font-weight:900;direction:ltr}.conduct-icon:before{content:"⚡";position:absolute;inset:0;display:grid;place-items:center;color:var(--blue);font-size:1.5rem}.hammer-icon:before{content:"🔨";position:absolute;inset:0;display:grid;place-items:center;font-size:1.35rem}.strongbond-icon:before{content:"●—●";position:absolute;inset:0;display:grid;place-items:center;color:var(--green);font-size:.9rem;font-weight:900;direction:ltr}.hard-icon:before{content:"◆";position:absolute;inset:0;display:grid;place-items:center;color:var(--pink);font-size:1.55rem}.brittle-icon:before{content:"✦";position:absolute;inset:0;display:grid;place-items:center;color:var(--orange);font-size:1.5rem}.meltconduct-icon:before{content:"⇄";position:absolute;inset:0;display:grid;place-items:center;color:var(--purple);font-size:1.5rem;font-weight:900}
.interaction-panel{margin-top:26px;padding:22px;border:1px solid rgba(22,119,200,.14);border-radius:20px;background:linear-gradient(145deg,rgba(223,250,255,.72),rgba(242,248,252,.9))}.molecular-panel{background:linear-gradient(145deg,#f5f0ff,#f8fbfd);border-color:rgba(138,91,212,.2)}.network-panel{background:linear-gradient(145deg,#eaf9ff,#f8fbfd)}.metallic-panel{background:linear-gradient(145deg,#fff6ea,#f8fbfd);border-color:rgba(255,155,66,.22)}.ionic-panel{background:linear-gradient(145deg,#fff0f7,#f8fbfd);border-color:rgba(231,68,147,.18)}.identify-panel{background:linear-gradient(145deg,#eafaf4,#f8fbfd);border-color:rgba(38,185,131,.2)}.interaction-heading{display:flex;align-items:center;justify-content:space-between;gap:18px;margin-bottom:18px}.interaction-heading>div{display:flex;flex-direction:column}.interaction-heading span{color:var(--blue);font-size:.75rem;font-weight:800}.interaction-heading strong{color:var(--navy-900);font-size:1.05rem}.interaction-heading output{padding:7px 11px;color:var(--navy-800);border:1px solid rgba(22,119,200,.16);border-radius:9px;background:#fff;font-size:.79rem;font-weight:800;white-space:nowrap}.segmented{display:grid;grid-template-columns:repeat(3,1fr);gap:7px;padding:6px;border-radius:16px;background:#e7eff4}.segmented.two{grid-template-columns:repeat(2,1fr)}.segmented button{padding:11px 10px;color:var(--muted);border-radius:12px;background:transparent;cursor:pointer;font-weight:800}.segmented button.active{color:#fff;background:var(--navy-800);box-shadow:0 8px 20px rgba(9,52,84,.18)}.evidence-strip{display:grid;grid-template-columns:repeat(3,1fr);gap:10px;margin-top:14px}.evidence-strip div{padding:13px;border-radius:13px;background:#fff;border:1px solid var(--line)}.evidence-strip span{display:block;color:var(--muted);font-size:.7rem}.evidence-strip b{color:var(--navy-800);font-size:.85rem}.model-note{margin:14px 0 0;color:var(--muted);font-size:.82rem}.model-note strong{color:var(--pink)}.range-row{display:grid;grid-template-columns:130px 1fr 88px;align-items:center;gap:14px;color:var(--muted);font-size:.84rem;font-weight:700}.range-row+.range-row{margin-top:14px}.range-row output{text-align:center;direction:ltr;color:var(--navy-800);font-weight:900}.range-row input{width:100%}input[type=range]{height:7px;appearance:none;border-radius:99px;outline:none;background:linear-gradient(90deg,var(--blue),var(--cyan));cursor:pointer}input[type=range]::-webkit-slider-thumb{width:22px;height:22px;appearance:none;border:4px solid #fff;border-radius:50%;background:var(--blue);box-shadow:0 3px 10px rgba(6,42,73,.25)}input[type=range]::-moz-range-thumb{width:16px;height:16px;border:4px solid #fff;border-radius:50%;background:var(--blue);box-shadow:0 3px 10px rgba(6,42,73,.25)}input[type=range]:focus-visible{outline:3px solid rgba(34,199,216,.55);outline-offset:3px}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid rgba(34,199,216,.6);outline-offset:2px;border-radius:8px}.verification-card{display:grid;grid-template-columns:105px 1fr;align-items:start;gap:14px;margin-top:16px;padding:15px 17px;border-right:4px solid var(--green);border-radius:13px;background:#ecfaf5}.verification-card strong{color:#18855e}.verification-card p{margin:0;color:#557267;font-size:.84rem}
.science-pair{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:22px 0}.formula-card{display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:126px;padding:22px;color:#fff;border-radius:20px;background:radial-gradient(circle at 20% 0,rgba(34,199,216,.32),transparent 35%),linear-gradient(145deg,var(--navy-900),var(--navy-700));box-shadow:0 18px 35px rgba(6,42,73,.18);text-align:center}.formula-card span{color:#99c7d8;font-size:.83rem}.formula-card strong{margin-top:7px;font-size:clamp(1.05rem,2vw,1.4rem);font-weight:800}.formula-card p{margin:7px 0 0;color:#c6dce9;font-size:.8rem}.formula-card.amorph{background:radial-gradient(circle at 20% 0,rgba(138,91,212,.34),transparent 35%),linear-gradient(145deg,#241a4a,#4b3a86)}.fact-card{display:flex;flex-direction:column;justify-content:center;padding:20px;border-radius:20px;background:#fff3f8;border:1px solid #f2d1e2}.fact-card b{color:var(--pink)}.fact-card p{margin:6px 0 0;color:#796474;font-size:.83rem}.violet-card{background:#f4efff;border-color:#ddd0f5}.violet-card b{color:var(--purple)}.violet-card p{color:#665a7d}.blue-card{background:#edf6ff;border-color:#cbe2f6}.blue-card b{color:var(--blue)}.blue-card p{color:#5a6e80}.table-wrap{overflow:auto;margin-top:20px;border:1px solid var(--line);border-radius:16px;background:#fff}.table-wrap table{width:100%;border-collapse:collapse;min-width:640px}.table-wrap th,.table-wrap td{padding:14px 13px;border-bottom:1px solid var(--line);text-align:center;font-size:.82rem}.table-wrap th{color:var(--navy-800);background:#eaf3f9}.table-wrap tr:last-child td{border-bottom:0}.table-wrap td[dir=ltr]{font-family:"Segoe UI",Tahoma,Arial,sans-serif;font-size:.8rem}
.life-link{display:grid;grid-template-columns:64px 1fr;align-items:center;gap:18px;margin-top:22px;padding:20px;border-radius:20px;color:#fff;background:linear-gradient(145deg,#0e6583,#1597a6)}.life-icon{display:grid;place-items:center;width:58px;height:58px;border:1px solid rgba(255,255,255,.28);border-radius:17px;background:rgba(255,255,255,.1);font-size:1.7rem}.life-link b{display:block}.life-link p{margin:3px 0 0;color:#d4f0f3;font-size:.82rem}.enrich-note{display:grid;grid-template-columns:52px 1fr;gap:15px;align-items:center;margin-top:20px;padding:17px;border:1px solid #f0e2b8;border-radius:17px;background:#fffbe9}.enrich-icon{display:grid;place-items:center;width:46px;height:46px;color:#8a6d0b;border-radius:14px;background:#f7e9bb;font-size:1.3rem;font-weight:900;font-style:italic}.enrich-note b{color:#7a5f06}.enrich-note p{margin:4px 0 0;color:#6d6448;font-size:.83rem}.check-card{margin-top:22px;padding:18px 20px;border:1px dashed rgba(38,185,131,.45);border-radius:17px;background:#f4fdf9}.check-card>b{color:#15805c}.check-card>p{margin:6px 0 4px;color:var(--muted);font-size:.9rem}.check-card details{margin-top:8px}.check-card summary{cursor:pointer;color:var(--navy-800);font-size:.84rem;font-weight:800}.check-card details p{margin:8px 0 0;color:#4f6a5e;font-size:.84rem}
.toggle-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:14px}.toggle-block{display:flex;flex-direction:column;gap:7px}.toggle-label{color:var(--muted);font-size:.74rem;font-weight:800}.preset-row{display:flex;flex-wrap:wrap;align-items:center;gap:8px;margin-top:16px}.preset-row>span{color:var(--muted);font-size:.78rem;font-weight:800}.preset{padding:8px 13px;color:var(--navy-800);border:1px solid var(--line);border-radius:11px;background:#fff;cursor:pointer;font-size:.76rem;font-weight:800;transition:.15s}.preset:hover{border-color:var(--green);background:#f2fbf6}.experiment-actions{display:flex;justify-content:center;gap:10px;margin-top:16px}.worked-example{margin-top:17px;overflow:hidden;border:1px solid var(--line);border-radius:15px;background:#fff}.worked-example summary{padding:15px 17px;color:var(--navy-800);cursor:pointer;font-size:.86rem;font-weight:700}.worked-example summary span{margin-left:8px;color:var(--pink)}.worked-example>div{padding:0 17px 15px;border-top:1px solid var(--line)}.worked-example li,.worked-example p{color:var(--muted);font-size:.84rem}
.quiz{display:grid;gap:15px}.quiz fieldset{margin:0;padding:20px;border:1px solid var(--line);border-radius:17px;background:#fbfdff}.quiz legend{padding:0 8px;color:var(--navy-800);font-weight:900}.quiz fieldset>label{display:flex;align-items:center;gap:8px;margin-top:10px;padding:9px 11px;border-radius:11px;color:var(--muted);background:#fff;border:1px solid #edf2f5;cursor:pointer}.quiz fieldset>label:hover{border-color:#b8dbea;background:#f5fbff}.quiz input{accent-color:var(--blue)}.quiz-feedback{display:none;margin:12px 0 0;padding:10px 12px;border-radius:10px;font-size:.82rem}.quiz fieldset.correct .quiz-feedback{display:block;color:#166d50;background:#e9f9f2}.quiz fieldset.incorrect .quiz-feedback{display:block;color:#9b3636;background:#fff0f0}.quiz-actions{display:flex;flex-wrap:wrap;align-items:center;gap:10px}.quiz-actions output{margin-right:auto;padding:10px 14px;border-radius:12px;color:var(--navy-800);background:#fff;border:1px solid var(--line);font-weight:900}.review-grid{display:grid;gap:10px;margin-top:24px}.review-grid details{padding:15px 17px;border:1px solid var(--line);border-radius:14px;background:#fff}.review-grid summary{cursor:pointer;color:var(--navy-800);font-weight:900}.review-grid p{margin:10px 0 0;color:var(--muted);font-size:.85rem}
footer{display:grid;grid-template-columns:1fr auto auto;align-items:center;gap:26px;padding:32px clamp(24px,6vw,90px);color:#c5d7e4;background:var(--navy-950);border-top:1px solid rgba(255,255,255,.08)}.footer-brand{display:flex;flex-direction:column}.footer-brand strong{color:#fff;font-size:1.02rem}.footer-brand span,footer p,footer a{font-size:.78rem}footer p{margin:0}footer a{color:var(--cyan)}.noscript{position:fixed;z-index:100;inset:auto 20px 20px;padding:15px;color:#fff;border-radius:12px;background:#9f2f2f}
@media (max-width:1180px){.desktop-nav{display:none}.mobile-nav-toggle{display:block}body.mobile-nav-open .mobile-nav{display:grid}.lesson-layout{grid-template-columns:minmax(330px,40vw) minmax(0,1fr)}.sticky-stage{padding-left:14px}.concept-grid.three{grid-template-columns:1fr}.concept-card{min-height:0}.evidence-strip{grid-template-columns:1fr}.toggle-grid{grid-template-columns:1fr}}
@media (max-width:900px){html{scroll-padding-top:78px}.topbar{min-height:68px;padding:9px 14px}.mobile-nav{top:68px}.brand-copy small{display:none}.header-actions .icon-button{width:40px;height:40px}.section-rail{display:none}.hero{grid-template-columns:1fr;gap:30px;min-height:auto;padding:110px 18px 42px}.hero h1{font-size:clamp(3.2rem,17vw,5.5rem)}.hero-visual{order:2}.hero-stage-shell{transform:none}.stage-shell{min-height:430px;border-radius:24px}.hero-stat-grid{grid-template-columns:repeat(3,1fr)}.lesson-layout{display:flex;flex-direction:column}.sticky-stage{position:sticky;z-index:18;top:68px;width:100%;height:42vh;min-height:300px;padding:10px 12px;background:rgba(244,248,251,.92);backdrop-filter:blur(10px);transition:height .2s,min-height .2s}.sticky-stage .stage-shell{border-radius:20px}.mobile-stage-toggle{display:block}.sticky-stage.collapsed{height:64px;min-height:64px}.sticky-stage.collapsed .stage-shell{display:none}.lesson-content{width:100%}.content-section{min-height:auto;padding:48px 14px}.lesson-card{padding:26px 18px;border-radius:22px}.lesson-card h2{font-size:clamp(2.1rem,11vw,3.4rem)}.section-intro{font-size:.96rem}.stage-hud{top:14px;right:14px;left:150px}.stage-hud strong{font-size:1rem}.hud-metrics span:nth-child(2){display:none}.stage-bottom{right:10px;left:10px;bottom:10px}.live-metric{min-width:0;flex:1;padding:6px 5px}.science-pair{grid-template-columns:1fr}.range-row{grid-template-columns:1fr 72px;gap:8px}.range-row>span{grid-column:1/-1}.interaction-heading{align-items:flex-start;flex-direction:column}.interaction-heading output{align-self:stretch;text-align:center}.life-link{grid-template-columns:48px 1fr}.life-icon{width:45px;height:45px}.quiz-actions output{width:100%;margin:0;text-align:center}footer{grid-template-columns:1fr;gap:8px;text-align:center}.footer-brand{align-items:center}}
@media (max-width:560px){.hero-stat-grid{grid-template-columns:1fr}.hero-stat-grid div{display:flex;align-items:center;justify-content:space-between}.hero-stat-grid strong{font-size:1.1rem}.hero-actions{flex-direction:column}.primary-button,.ghost-button{width:100%}.stage-shell{min-height:380px}.sticky-stage{height:38vh;min-height:280px}.hud-metrics{display:none}.stage-bottom{display:grid;grid-template-columns:repeat(3,1fr)}.stage-tool{top:12px;left:12px;padding:0 10px}.stage-tool span{display:none}.segmented,.segmented.two{grid-template-columns:1fr}.evidence-strip{grid-template-columns:1fr}.verification-card{grid-template-columns:1fr}.table-wrap{margin-inline:-6px}.enrich-note{grid-template-columns:1fr;text-align:right}.toggle-grid{grid-template-columns:1fr}.quiz fieldset{padding:16px 12px}.section-number{font-size:4.5rem}.formula-card strong{font-size:1rem}.life-link{grid-template-columns:1fr;text-align:center}.life-icon{margin:auto}}
@media (prefers-reduced-motion:reduce){html{scroll-behavior:auto}*,*:before,*:after{animation-duration:.001ms!important;animation-iteration-count:1!important;transition-duration:.001ms!important}}
.fact-card b{color:#a91f60}.violet-card b{color:#6840a8}.blue-card b{color:#0b609f}

/* ---------- درس الحالة الغازية: أيقونات مفاهيم خاصة ---------- */
.icon-particles:before{content:"∴";position:absolute;inset:0;display:grid;place-items:center;color:var(--blue);font-size:1.6rem;font-weight:900}
.icon-motion:before{content:"⇢";position:absolute;inset:0;display:grid;place-items:center;color:var(--cyan);font-size:1.7rem;font-weight:900}
.icon-elastic:before{content:"Eₖ";position:absolute;inset:0;display:grid;place-items:center;color:var(--green);font-size:1.05rem;font-weight:900;direction:ltr}
.icon-noattr:before{content:"F=0";position:absolute;inset:0;display:grid;place-items:center;color:var(--pink);font-size:.95rem;font-weight:900;direction:ltr}
.icon-ke:before{content:"KE";position:absolute;inset:0;display:grid;place-items:center;color:var(--orange);font-size:1.05rem;font-weight:900;direction:ltr}
.icon-ideal:before{content:"i";position:absolute;inset:0;display:grid;place-items:center;color:var(--purple);font-size:1.5rem;font-weight:900;font-style:italic}
.icon-atm:before{content:"atm";position:absolute;inset:0;display:grid;place-items:center;color:var(--blue);font-size:.9rem;font-weight:900;direction:ltr}
.icon-mmhg:before{content:"mmHg";position:absolute;inset:0;display:grid;place-items:center;color:var(--green);font-size:.72rem;font-weight:900;direction:ltr}
.icon-kpa:before{content:"kPa";position:absolute;inset:0;display:grid;place-items:center;color:var(--pink);font-size:.85rem;font-weight:900;direction:ltr}

/* ---------- صفحة فهرس الدروس (hub) ---------- */
.hub-hero{position:relative;display:flex;flex-direction:column;align-items:center;justify-content:center;min-height:100vh;padding:120px clamp(20px,5vw,80px) 70px;color:#fff;text-align:center;background:radial-gradient(circle at 80% 18%,rgba(34,199,216,.19),transparent 28%),radial-gradient(circle at 10% 70%,rgba(138,91,212,.14),transparent 24%),linear-gradient(135deg,#041426,#072a49 58%,#061d35)}
.hub-dossier{display:inline-block;padding:7px 22px;border-radius:999px;background:linear-gradient(135deg,#72e2ed,var(--cyan));color:var(--navy-950);font-weight:900;font-size:clamp(.9rem,1.6vw,1.1rem);letter-spacing:.06em;box-shadow:0 10px 30px rgba(34,199,216,.3)}
.hub-hero h1{margin:20px 0 12px;line-height:1.12;font-weight:900;font-size:clamp(3.2rem,10vw,7.8rem);background:linear-gradient(90deg,#fff,#8eeeff 45%,#c9a7ff 75%,#fff);background-size:220% 100%;-webkit-background-clip:text;background-clip:text;color:transparent;animation:hubShimmer 8s linear infinite}
@keyframes hubShimmer{to{background-position:220% 0}}
.hub-teacher{margin:0;color:#eaf6fb;font-size:clamp(1.15rem,2.6vw,1.7rem);font-weight:800}
.hub-teacher strong{color:var(--cyan)}
.hub-subject{margin:8px 0 0;color:#9fc6d8;font-size:clamp(.85rem,1.6vw,1rem);font-weight:700}
.hub-contact{justify-content:center;margin-top:28px}
.hub-contact .teacher-cta{width:100%;text-align:center;color:#ffb1d9}
.scroll-cue{display:inline-flex;flex-direction:column;align-items:center;gap:6px;margin-top:54px;color:#8fc2d8;font-size:.8rem;font-weight:800;animation:cueFloat 2.2s ease-in-out infinite}
.scroll-cue svg{width:22px;height:22px;animation:cueDrop 1.6s ease-in-out infinite}
@keyframes cueFloat{0%,100%{transform:translateY(0)}50%{transform:translateY(-7px)}}
@keyframes cueDrop{0%,100%{transform:translateY(-2px);opacity:.5}50%{transform:translateY(3px);opacity:1}}
.hub-main{max-width:1050px;margin:0 auto;padding:64px clamp(18px,4vw,50px) 84px}
.hub-unit{display:flex;align-items:baseline;justify-content:space-between;gap:14px;margin-bottom:26px;border-bottom:2px solid var(--line);padding-bottom:12px}
.hub-unit h2{margin:0;color:var(--navy-900);font-size:clamp(1.35rem,3vw,1.9rem);font-weight:900}
.hub-unit span{color:var(--muted);font-size:.85rem;font-weight:800}
.lesson-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:18px}
.lesson-tile{position:relative;overflow:hidden;display:flex;flex-direction:column;min-height:190px;padding:26px 24px;border:1px solid rgba(12,63,99,.1);border-radius:24px;background:rgba(255,255,255,.94);box-shadow:var(--shadow-soft);transition:transform .25s,box-shadow .25s}
.lesson-tile:before{content:"";position:absolute;inset:0 0 auto;height:5px;background:linear-gradient(90deg,var(--blue),var(--cyan),var(--purple))}
.lesson-tile.available:hover{transform:translateY(-5px);box-shadow:var(--shadow)}
.lesson-tile .tile-tag{align-self:flex-start;padding:5px 11px;border-radius:999px;font-size:.7rem;font-weight:900}
.lesson-tile h3{margin:14px 0 8px;color:var(--navy-900);font-size:1.45rem;font-weight:900}
.lesson-tile p{margin:0 0 18px;color:var(--muted);font-size:.88rem;line-height:1.8;flex:1}
.tile-open{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:0 18px;border-radius:13px;color:var(--navy-950);background:linear-gradient(135deg,#72e2ed,var(--cyan));font-weight:800;font-size:.9rem;transition:.2s}
.tile-open:hover{transform:translateY(-2px);box-shadow:0 12px 26px rgba(34,199,216,.28)}
.lesson-tile.soon{background:rgba(255,255,255,.55);border-style:dashed}
.lesson-tile.soon .tile-open{color:var(--muted);background:#e7eff4;cursor:not-allowed;pointer-events:none;box-shadow:none}
.reveal{opacity:0;transform:translateY(36px);filter:blur(7px);transition:opacity .7s ease,transform .7s cubic-bezier(.2,.8,.2,1),filter .7s ease}
.reveal.in{opacity:1;transform:none;filter:none}
.reveal[data-d="1"]{transition-delay:.08s}.reveal[data-d="2"]{transition-delay:.16s}.reveal[data-d="3"]{transition-delay:.24s}.reveal[data-d="4"]{transition-delay:.32s}.reveal[data-d="5"]{transition-delay:.4s}
@media (max-width:900px){.hub-hero{padding-top:104px}.hub-main{padding:44px 14px 64px}}
@media (prefers-reduced-motion:reduce){.hub-hero h1{animation:none}.scroll-cue,.scroll-cue svg{animation:none}.reveal{opacity:1;transform:none;filter:none;transition:none}}

/* ===== إخفاء المسرح عند قسم المراجعة (assessment) ===== */
body.stage-hidden .sticky-stage{display:none}
@media (min-width:901px){
  body.stage-hidden .lesson-layout{grid-template-columns:minmax(0,1fr)}
  body.stage-hidden .lesson-content{width:100%;max-width:1150px;margin:0 auto}
}

/* ===== لوحة التحكم داخل ملء الشاشة (حاسوب فقط) ===== */
.fs-controls{display:none}
.stage-shell.fs-with-controls .fs-controls{display:block;position:absolute;z-index:8;top:76px;bottom:76px;right:16px;width:min(440px,40vw);overflow:auto;padding:16px;background:rgba(244,248,251,.97);border:1px solid rgba(123,224,236,.35);border-radius:20px;direction:rtl;scrollbar-width:thin}
.stage-shell.fs-with-controls .fs-controls .interaction-panel{margin:0;box-shadow:none}
.stage-shell.fs-with-controls .stage-hud{right:calc(min(440px,40vw) + 40px)}
.stage-shell.fs-with-controls .stage-bottom{right:calc(min(440px,40vw) + 24px)}
.stage-shell.fs-with-controls .canvas-hint{display:none}
@media (max-width:900px){
  .stage-shell.fs-with-controls .fs-controls{display:none}
  .stage-shell.fs-with-controls .stage-hud{right:14px}
  .stage-shell.fs-with-controls .stage-bottom{right:10px}
}

/* ===== شريط المواضيع داخل ملء الشاشة ===== */
.fs-topics{display:none}
.stage-shell.fs-with-controls .fs-topics{display:flex;align-items:center;gap:10px;position:absolute;z-index:9;top:14px;right:18px;left:190px;direction:rtl}
.fs-current{flex:0 0 auto;padding:9px 15px;border-radius:14px;color:#eafcff;font-size:.82rem;font-weight:900;background:rgba(34,199,216,.14);border:1px solid rgba(123,224,236,.4);box-shadow:0 6px 18px rgba(34,199,216,.18)}
.fs-current.swap{animation:fsSwap .5s cubic-bezier(.2,.8,.2,1)}
@keyframes fsSwap{0%{opacity:0;transform:translateY(10px) scale(.94)}60%{opacity:1;transform:translateY(-2px) scale(1.03)}100%{opacity:1;transform:none}}
.fs-topics-btns{display:flex;gap:8px;overflow-x:auto;padding:4px 2px;scrollbar-width:none;-webkit-overflow-scrolling:touch}
.fs-topics-btns::-webkit-scrollbar{display:none}
.fs-topics-btns button{flex:0 0 auto;padding:8px 14px;border-radius:999px;border:1px solid rgba(255,255,255,.16);background:rgba(4,20,38,.55);color:#bfe3ee;font-size:.78rem;font-weight:800;cursor:pointer;backdrop-filter:blur(8px);transition:transform .25s,background .25s,color .25s,border-color .25s,box-shadow .25s}
.fs-topics-btns button:hover{transform:translateY(-2px);background:rgba(20,82,108,.8)}
.fs-topics-btns button.active{background:linear-gradient(135deg,#72e2ed,var(--cyan));color:var(--navy-950);border-color:transparent;transform:scale(1.07);box-shadow:0 8px 22px rgba(34,199,216,.35)}
/* وميض لطيف عند تبديل موضوع المحاكاة */
.stage-shell.topic-swap #solidCanvas{animation:topicFlash .6s ease}
@keyframes topicFlash{0%{filter:none}35%{filter:brightness(1.55) saturate(1.25)}100%{filter:none}}
/* إزاحة HUD أسفل شريط المواضيع في ملء الشاشة */
.stage-shell.fs-with-controls .stage-hud{top:66px}
@media (max-width:900px){
  .stage-shell.fs-with-controls .fs-topics{top:64px;right:12px;left:12px}
  .stage-shell.fs-with-controls .stage-hud{top:112px}
  .fs-current{font-size:.72rem;padding:7px 10px}
  .fs-topics-btns button{font-size:.7rem;padding:7px 10px}
}
@media (prefers-reduced-motion:reduce){.stage-shell.topic-swap #solidCanvas,.fs-current.swap{animation:none}}

/* ===== بطاقة المعلم والتواصل ===== */
.teacher-card{display:flex;flex-wrap:wrap;align-items:center;justify-content:space-between;gap:18px;margin-top:28px;padding:22px 26px;border-radius:24px;background:linear-gradient(135deg,rgba(34,199,216,.13),rgba(138,91,212,.1)),#fff;border:1px solid rgba(34,199,216,.4);box-shadow:var(--shadow-soft)}
.teacher-id{display:flex;flex-direction:column;gap:5px;min-width:220px}
.teacher-badge{align-self:flex-start;padding:5px 13px;border-radius:999px;background:linear-gradient(135deg,#72e2ed,var(--cyan));color:var(--navy-950);font-size:.72rem;font-weight:900;letter-spacing:.2px}
.teacher-id strong{font-size:clamp(1.35rem,2.6vw,1.95rem);font-weight:900;color:var(--navy-900);line-height:1.35}
.teacher-role{color:var(--muted);font-size:.8rem}
.teacher-contact{display:flex;flex-wrap:wrap;align-items:center;gap:10px}
.teacher-cta{width:100%;color:var(--pink);font-size:.8rem;font-weight:900}
.contact-btn{display:inline-flex;align-items:center;gap:8px;padding:12px 18px;border-radius:14px;font-weight:900;font-size:.9rem;color:#fff;transition:transform .2s,box-shadow .2s}
.contact-btn svg{width:18px;height:18px;flex:0 0 auto}
.contact-btn.call{background:linear-gradient(135deg,var(--navy-800),var(--blue))}
.contact-btn.whatsapp{background:linear-gradient(135deg,#1faa59,#25d366)}
.contact-btn:hover{transform:translateY(-2px);box-shadow:0 12px 26px rgba(7,37,65,.2)}
/* نسخة الهيرو الداكنة في صفحة الدرس */
.hero .teacher-card{background:linear-gradient(135deg,rgba(34,199,216,.16),rgba(138,91,212,.12)),rgba(255,255,255,.05);border-color:rgba(123,224,236,.4)}
.hero .teacher-id strong{color:#fff}
.hero .teacher-role{color:#9fc6d8}
.footer-contact{margin:0;font-size:.82rem}
.footer-contact a{color:var(--cyan);font-weight:900}
@media (max-width:900px){.teacher-card{flex-direction:column;align-items:stretch;text-align:center}.teacher-id{align-items:center}.teacher-badge{align-self:center}.teacher-contact{justify-content:center}.contact-btn{flex:1;justify-content:center;min-width:150px}}

/* ===== أدوات اتجاه النص (bidi) ===== */
.ltr{direction:ltr;unicode-bidi:isolate}
bdi[dir=ltr]{unicode-bidi:isolate}

/* ضبط HUD تحت الزر المصغّر على الجوال الصغير */
@media (max-width:560px){.stage-hud{left:64px}}