:root{--bg:#f5f1e7;--card:#fffdf8;--ink:#17231e;--muted:#68736d;--line:#d6ddd7;--green:#0d6753;--mint:#dcefe6;--amber:#d79b3f;--blue:#e6f0f5;--shadow:0 18px 55px rgba(25,40,33,.09)}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;color:var(--ink);font-family:Inter,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;background:radial-gradient(circle at 7% 0,rgba(215,155,63,.13),transparent 24%),radial-gradient(circle at 95% 2%,rgba(13,103,83,.11),transparent 28%),var(--bg)}a{color:inherit}.page{width:min(1240px,calc(100% - 26px));margin:auto;padding:18px 0 55px}.top{display:flex;align-items:center;justify-content:space-between;gap:14px}.brand{display:flex;align-items:center;gap:9px;font-weight:900;text-decoration:none}.logo{width:40px;height:40px;border-radius:13px;border:1px solid #c9d8d0;background:linear-gradient(145deg,var(--mint),#fff);display:grid;place-items:center;color:var(--green)}.top-actions{display:flex;align-items:center;gap:8px}.pill,.lang summary{border:1px solid var(--line);background:rgba(255,253,248,.92);padding:9px 12px;border-radius:999px;text-decoration:none;font-weight:750;font-size:.82rem;cursor:pointer}.lang{position:relative}.lang-panel{position:absolute;right:0;top:48px;width:min(620px,88vw);padding:12px;background:var(--card);border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);z-index:10}.lang-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:5px}.lang-grid a{display:flex;justify-content:space-between;gap:5px;text-decoration:none;padding:7px 8px;border-radius:9px;font-size:.75rem}.lang-grid a:hover,.lang-grid a.active{background:var(--mint)}.lang-grid small{color:var(--muted)}.crumb{display:flex;gap:8px;flex-wrap:wrap;color:var(--muted);font-size:.82rem;margin:23px 0}.hero{display:grid;grid-template-columns:1.5fr .7fr;gap:20px;align-items:center;padding:28px;border:1px solid var(--line);border-radius:28px;background:rgba(255,253,248,.78);box-shadow:var(--shadow)}.kicker,.eyebrow{font-size:.72rem;letter-spacing:.13em;text-transform:uppercase;color:var(--green);font-weight:900}.hero h1{font-size:clamp(2.3rem,6vw,5rem);letter-spacing:-.055em;line-height:.95;margin:10px 0 14px}.hero p{font-size:1.05rem;line-height:1.65;max-width:780px;color:#44514a}.hero-art{min-height:180px;border-radius:24px;background:linear-gradient(145deg,var(--mint),#fff);display:grid;place-items:center;font-weight:900;font-size:2.1rem;color:var(--green);border:1px solid #cbded5}.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin-top:18px}.card,.story,.toolbox{background:var(--card);border:1px solid var(--line);border-radius:20px;padding:18px;box-shadow:0 8px 25px rgba(25,40,33,.045)}.card{text-decoration:none;display:flex;flex-direction:column;gap:7px;min-height:140px}.card strong{font-size:1.05rem}.card span,.story p{color:var(--muted);line-height:1.55}.tag{display:inline-flex;width:max-content;padding:5px 8px;border-radius:999px;background:var(--mint);color:var(--green);font-size:.72rem;font-weight:850}.section-title{margin:34px 0 10px;font-size:1.7rem;letter-spacing:-.03em}.story{margin-top:14px}.story h2{margin:6px 0 8px;font-size:1.45rem}.fact{background:var(--blue);border-radius:14px;padding:12px 14px;margin:10px 0;font-weight:750}.formula{font-family:ui-monospace,SFMono-Regular,Menlo,monospace;font-size:1.35rem;background:#f0f5f2;border:1px solid var(--line);padding:14px;border-radius:14px;overflow:auto}.toolbox{margin-top:16px}.toolgrid{display:grid;grid-template-columns:repeat(3,1fr);gap:10px}.field{display:flex;flex-direction:column;gap:6px}.field label{font-size:.8rem;font-weight:800}.field input,.field select,.toolbox textarea{width:100%;border:1px solid #cdd7d1;background:#fff;padding:12px;border-radius:12px;font:inherit}.actions{display:flex;gap:8px;margin-top:12px;flex-wrap:wrap}.btn{border:0;border-radius:12px;padding:11px 14px;font-weight:850;cursor:pointer;background:var(--green);color:white}.btn.secondary{background:#edf2ef;color:var(--ink);border:1px solid var(--line)}.result{margin-top:12px;background:var(--blue);border:1px solid #cddde4;border-radius:14px;padding:14px;min-height:52px}.result strong{display:block;font-size:1.35rem}.list{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}.list a{text-decoration:none;padding:12px;border:1px solid var(--line);border-radius:12px;background:#fff}.footer{display:flex;justify-content:space-between;gap:15px;flex-wrap:wrap;border-top:1px solid var(--line);margin-top:32px;padding-top:20px;color:var(--muted);font-size:.82rem}.footer nav{display:flex;gap:12px;flex-wrap:wrap}.dark{--bg:#101814;--card:#17221d;--ink:#ebf1ed;--muted:#aab5af;--line:#304039;--mint:#1d352c;--blue:#1b2d35;background:#101814}.dark .pill,.dark .lang summary,.dark .field input,.dark .field select,.dark .toolbox textarea,.dark .list a{background:#17221d;color:var(--ink)}.dark .formula{background:#1b2b24}@media(max-width:850px){.hero{grid-template-columns:1fr}.hero-art{display:none}.grid{grid-template-columns:1fr 1fr}.toolgrid{grid-template-columns:1fr}.lang-grid{grid-template-columns:repeat(2,1fr)}}@media(max-width:560px){.grid,.list{grid-template-columns:1fr}.page{width:min(100% - 16px,1240px)}.hero{padding:20px}.top .pill{display:none}.hero h1{font-size:2.75rem}}

/* RTL isolation for Arabic and Hebrew science pages */
html[dir="rtl"] body{direction:rtl;text-align:right}html[dir="rtl"] .top,html[dir="rtl"] .topbar,html[dir="rtl"] .footer,html[dir="rtl"] .crumb,html[dir="rtl"] .actions{direction:rtl}html[dir="rtl"] .lang-panel,html[dir="rtl"] .lang-menu{right:auto;left:0}html[dir="rtl"] .hero,html[dir="rtl"] .grid,html[dir="rtl"] .story,html[dir="rtl"] .card{text-align:right}html[dir="rtl"] .formula,html[dir="rtl"] .hero-art[dir="ltr"],html[dir="rtl"] bdi[dir="ltr"],html[dir="rtl"] input[dir="ltr"],html[dir="rtl"] input[type="number"],html[dir="rtl"] .result strong{direction:ltr;unicode-bidi:isolate;text-align:left}html[dir="rtl"] .formula{font-variant-numeric:tabular-nums}html[dir="rtl"] .toolgrid{direction:rtl}html[dir="rtl"] .toolbox input:not([dir="ltr"]){text-align:right}html[dir="rtl"] .brand{direction:ltr}html[dir="rtl"] .lang-item{unicode-bidi:isolate}.topbar{display:flex;align-items:center;justify-content:space-between;gap:16px;flex-wrap:wrap}.topbar .brand{display:flex;align-items:center;gap:8px}.brand-mark{width:38px;height:38px;border:1px solid var(--line);border-radius:12px;display:grid;place-items:center;background:var(--mint);color:var(--green);font-weight:900}.topbar .nav{display:flex;align-items:center;gap:16px;flex-wrap:wrap}.topbar .nav a{text-decoration:none;font-weight:750}.topbar .actions{margin-top:0;align-items:center}.topbar .lang{position:relative}.topbar .lang-menu{position:absolute;left:0;right:auto;top:46px;width:min(620px,88vw);display:grid;grid-template-columns:repeat(4,1fr);gap:5px;padding:12px;background:var(--card);border:1px solid var(--line);border-radius:18px;box-shadow:var(--shadow);z-index:20}.topbar .lang-item{display:block;text-decoration:none;padding:7px 8px;border-radius:9px;font-size:.75rem}.topbar .lang-item:hover{background:var(--mint)}@media(max-width:700px){.topbar{align-items:flex-start}.topbar .nav{order:3;width:100%;gap:12px}.topbar .lang-menu{grid-template-columns:repeat(2,1fr)}}