:root{--ink:#f0f3e8;--teal:#bcdfc5;--paper:#092c23;--line:#406052;--gold:#f0d48d}
body{background:radial-gradient(ellipse at 15% 10%,#214a3b55,transparent 55%),radial-gradient(ellipse at 85% 60%,#50736018,transparent 60%),#092c23;color:var(--ink)}
header{background:#06251ee8;border-bottom:1px solid #8cab9555;padding-top:22px;padding-bottom:22px}.brand{letter-spacing:1.3px;font-size:14px;color:#e4eadb}main{max-width:1180px}.hero{position:relative;isolation:isolate;padding:68px 35px 55px;margin:0 -10px;gap:45px;min-height:480px}.hero:before{content:"";position:absolute;inset:0;z-index:-1;background:linear-gradient(90deg,#092c23 0%,#092c23eb 32%,#092c2390 72%,#092c23a0),url('chalkboard-reference.png') center/cover;opacity:.68;mask-image:linear-gradient(#000 80%,transparent)}
h1{font-family:'Chalkboard SE','Comic Sans MS',Georgia,serif;font-weight:500;letter-spacing:-1.8px;color:#f5f6e9;text-shadow:1px 0 #fff3;font-size:clamp(40px,6vw,68px)}h2,h3{color:#eff3e8}h2{font-family:'Chalkboard SE',Georgia,serif;font-weight:500;font-size:34px}.hero p{max-width:570px}.note,footer{color:#bed1c4}.eyebrow{color:#c2dcc1}.board{background:#103a2fee;border:1px solid #acc9b178;border-radius:5px;box-shadow:6px 7px 0 #021d1766;padding:29px;transform:rotate(-1deg)}.board:after{content:'●  ●  ●';display:block;letter-spacing:12px;font-size:13px;color:#e6e7ce88;text-align:right;margin-top:12px}.board .formula{font-family:'Chalkboard SE','Comic Sans MS',Georgia,serif;color:#f0d48d}.board .note{color:#c6d6ca}.board hr{border-color:#adc6b344}.tabs{background:#092c23f5;backdrop-filter:blur(12px);border-bottom:1px solid #8cac9566;padding:16px 0}.tabs button{color:#cadace;border-radius:5px}.tabs button[aria-selected=true]{background:#e8eedf;color:#12392d;box-shadow:0 3px 0 #b8cbb677}.tabs button:hover{background:#345747;color:#fff}.panel{padding:32px 0}.card{background:#123b30;border:1px solid #75947c6b;border-radius:7px;box-shadow:0 4px 12px #001e1722}.callout{background:#204b3c;border-color:#d7dcb5;color:#eef2e4}.num{color:#eed697}.pill{background:#315b47;color:#e7efdc}.formula{font-family:'Chalkboard SE',Georgia,serif;color:#f3dfa7}button,.btn{background:#e5ebd9;color:#143c2e;font-weight:650;border-radius:5px}button:hover,.btn:hover{background:#f4dca4;color:#163d2d}.ghost{background:#163d31;color:#e5eddc;border-color:#8eaa9477}.ghost:hover{background:#315c46;color:#fff}select,input,textarea{background:#0a2b23!important;color:#f1f4e8!important;border:1px solid #8eaa94!important;border-radius:5px!important}textarea::placeholder,input::placeholder{color:#b4c8bb}select{color-scheme:dark}input:disabled{background:#24483a!important}summary{color:#e3eace}details{border-color:#718d7755}a{color:#e4d99b}.steps li:before{background:#e2e9d5;color:#143c2e}button:focus-visible,a:focus-visible,select:focus-visible,input:focus-visible,textarea:focus-visible{outline:3px solid #f0d48d;outline-offset:4px}footer{margin-top:20px;border-color:#8cab9555}#solution:not(:empty){background:#123b30;border:1px solid #75947c6b;border-radius:7px;padding:25px;margin-top:25px}#solution h3{color:#f0d48d}#values label{color:#dce7d7}
@media(max-width:720px){.hero{padding:35px 10px 30px;margin:0;min-height:auto;gap:28px}.hero:before{background:linear-gradient(#092c23b0,#092c23ed),url('chalkboard-reference.png') center/cover}.board{transform:none}.tabs{gap:5px}.brand{font-size:11px;letter-spacing:.5px}h2{font-size:29px}}
@media print{body,header,.tabs,.card,.board,.callout,#solution:not(:empty){background:white!important;color:black!important;box-shadow:none}.hero:before,.board:after{display:none}h1,h2,h3,p,.note,.formula,footer,summary,.num{color:black!important}select,input,textarea{background:white!important;color:black!important}}