/* AI Tools for Education — approved brand system */
:root{--blue:#3e80bc;--teal:#489c8c;--ink:#193b58;--paper:#faf8f1;--white:#fff;--muted:#506579;--soft-blue:#e8f0f5;--soft-teal:#e8f2ef;--line:#dce3e5;--accent:#277f73}
*{box-sizing:border-box}html{scroll-behavior:smooth;scroll-padding-top:24px}body{margin:0;background:var(--paper);color:var(--ink);font:17px 'Segoe UI',Arial,sans-serif}a{color:inherit;text-underline-offset:3px}a:hover{color:var(--accent)}header,main,footer{max-width:1240px;margin:auto;padding:0 6%}header{display:flex;align-items:center;justify-content:space-between;gap:24px;padding-top:28px;padding-bottom:28px;border-bottom:1px solid var(--line)}.brand{display:flex;align-items:center;gap:18px;text-decoration:none;flex-shrink:0}.brand img{width:165px;height:auto;display:block}.publisher{border-left:1px solid var(--line);padding-left:18px;font-size:12px;line-height:1.6;max-width:160px}nav{display:flex;flex-wrap:wrap;gap:28px;font-size:15px}nav a{text-decoration:none}nav a:hover,nav a[aria-current=page]{text-decoration:underline}
h1,h2,h3{font-family:inherit;font-weight:600;letter-spacing:-.035em;line-height:1.2}h1{font-size:64px;line-height:1.08;margin:24px 0}h1 em{color:var(--accent);font-style:normal}h2{font-size:32px}h3{font-size:25px}p{line-height:1.7;color:var(--muted)}.hero{padding:68px 0;display:grid;grid-template-columns:1.25fr 1fr;gap:70px;align-items:center}.eyebrow{font-size:12px;font-weight:600;text-transform:uppercase;letter-spacing:2px;color:#3375ac}.dot{display:inline-block;background:var(--teal);width:8px;height:8px;border-radius:50%;margin-right:8px}.intro{font-size:19px;max-width:490px}.button{display:inline-flex;align-items:center;gap:30px;text-decoration:none;background:var(--ink);color:var(--white);padding:14px 23px;border-radius:8px;font-size:14px;font-weight:600;margin-top:18px;line-height:1.5}.button:hover{background:#245579;color:white}.desk{background:var(--soft-blue);border-radius:22px;padding:34px}.note small{font-size:11px;letter-spacing:2px}.note h2{font-size:29px;margin:18px 0}.note-row{background:white;padding:17px;display:flex;gap:14px;align-items:center;font-size:14px;border-radius:10px;margin-top:13px}.tile{width:36px;height:36px;flex-shrink:0;background:var(--soft-teal);color:var(--accent);display:grid;place-items:center;border-radius:8px}.caption{font-size:12px;text-align:center;margin:26px 0 0}
.section{border-top:1px solid var(--line);padding:55px 0}.section-head{display:flex;justify-content:space-between;gap:24px;align-items:end}.section h2{font-size:35px;margin:12px 0}.section-head p{max-width:390px;font-size:14px}.filters{display:flex;gap:8px;margin:27px 0;flex-wrap:wrap}button{font:inherit;color:var(--ink);border:1px solid var(--line);border-radius:24px;background:transparent;padding:10px 18px;cursor:pointer;min-height:44px}button:hover{background:var(--soft-blue)}button[aria-pressed=true]{background:var(--ink);color:white}.empty{border:1px dashed #a5b8c2;border-radius:16px;padding:40px;background:var(--soft-teal)}.empty h3{font-size:26px;margin:10px 0}.empty p{max-width:640px;margin-bottom:0}.label{font-size:11px;letter-spacing:1px;font-weight:600;text-transform:uppercase}.app-card{display:flex;gap:24px;padding:30px;background:white;border:1px solid var(--line);border-radius:16px}.app-card h3{font-size:25px;margin:12px 0}.app-card p{margin:12px 0}.app-card img{border-radius:14px;flex-shrink:0}.app-card .footer-links{margin-top:18px}.about{background:var(--soft-teal);padding:40px;border-radius:16px;display:grid;grid-template-columns:1fr 1fr;gap:45px}.about p{margin:0;font-size:16px}.about h2{font-size:28px;margin:12px 0 0}footer{padding-top:30px;padding-bottom:35px;display:flex;justify-content:space-between;gap:15px;font-size:12px;color:var(--muted)}.footer-links{display:flex;flex-wrap:wrap;gap:18px}
a:focus-visible,button:focus-visible,summary:focus-visible{outline:3px solid var(--blue);outline-offset:4px}.skip{position:absolute;top:-100px}.skip:focus{top:10px;background:white;padding:10px;z-index:9}[hidden]{display:none!important}
.document{max-width:900px;padding-top:45px;padding-bottom:50px;overflow-wrap:break-word}.document h1{font-size:clamp(36px,5vw,54px)}.document h2{font-size:27px;margin-top:36px}.document h3{font-size:23px}.document li{line-height:1.7;margin-bottom:8px;color:var(--muted)}.lead{font-size:20px}.panel{background:var(--soft-teal);border:1px solid var(--line);border-radius:12px;padding:25px;margin:25px 0}.contact{font-size:20px;overflow-wrap:anywhere}.subtle{font-size:14px}.toc{flex-wrap:wrap;margin:24px 0}.toc a{text-decoration:underline}details{border-bottom:1px solid var(--line);padding:20px 0}summary{cursor:pointer;line-height:1.5;font-weight:600}.document section{margin-top:35px}.activity{border-bottom:1px solid var(--line);padding:18px 0}.activity .num{font-size:12px;color:var(--accent);font-weight:600}.columns{display:grid;grid-template-columns:1fr 1fr;gap:30px}.art{display:none}.product-hero{padding:20px 0 35px}.price{font-weight:600}.product-hero .button{margin-bottom:20px}
@media(max-width:900px){header{flex-wrap:wrap}.hero{grid-template-columns:1fr;gap:28px;padding:40px 0}h1{font-size:46px}.publisher{display:none}.section-head,.about{display:block}.about p{margin-top:20px}}
@media(max-width:760px){nav{gap:16px}footer{flex-direction:column}.columns{display:block}.document{padding-top:30px}}
@media(max-width:600px){.brand img{width:150px}.app-card{flex-direction:column;padding:22px}.footer-links{gap:14px}.toc{gap:12px}header nav{gap:18px}.about{padding:26px}.desk{padding:24px}.empty{padding:26px}h1{font-size:clamp(36px,10vw,46px)}}
@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}}