*{box-sizing:border-box}body{margin:0;background:#101d29;color:#f1f4ec;font:16px/1.5 system-ui,sans-serif}main{max-width:520px;margin:auto;padding:16px}h1{font-size:clamp(24px,7vw,34px);line-height:1.1;margin:14px 0}h2{font-size:20px}p{margin:12px 0}small,.eyebrow{color:#c4d8d3}.panel{background:#1b303e;border:1px solid #537078;border-radius:15px;padding:12px;margin:14px 0}#board{display:grid;grid-template-columns:repeat(var(--cols),minmax(0,1fr));gap:3px;margin:16px 0}button,a{touch-action:manipulation}button{min-width:44px;min-height:44px;border:1px solid #84b9b0;border-radius:8px;background:#294959;color:#fff;font:inherit;padding:6px;overflow-wrap:anywhere}button:hover{background:#3c6571}button:focus-visible,a:focus-visible{outline:3px solid #ffce72;outline-offset:2px}button:disabled{opacity:1;background:#172c38;color:#b4c6c4;border-color:#395463}#board button{aspect-ratio:1;font-size:clamp(12px,3.6vw,18px);padding:2px}#controls{display:flex;flex-wrap:wrap;gap:7px}#controls button{flex:1 1 90px}a{display:inline-flex;align-items:center;min-height:44px;color:#aee7de;padding:6px 0;overflow-wrap:anywhere}#info{white-space:pre-wrap;font-size:14px}#message{border-left:3px solid #efc478;padding-left:10px}details summary{min-height:44px;cursor:pointer}footer{margin-top:24px}@media(max-width:350px){main{padding:10px}.panel{padding:8px}}

/* Steam engineering bench: paired valve ports and pressure table */
body{background:linear-gradient(125deg,#192c30,#0c191c);color:#eee6cd}.eyebrow{color:#d6b47a;letter-spacing:.15em}h1{font-family:Georgia,serif}.panel{background:#294147;border:2px solid #79908a;box-shadow:0 10px 40px #0005}#board{gap:12px;padding:16px;background:repeating-linear-gradient(0deg,#1a3035 0 3px,#1c3439 3px 30px);border-radius:14px}#board button{border:4px solid #b99561;border-radius:50%;background:radial-gradient(circle,#3e605c,#223e42);font-weight:700;white-space:pre-line;text-shadow:0 1px #000}#board button[data-port="minus"]{border-color:#879d99}#board button[data-signal="1"]{color:#8be2d9}#board button[data-signal="2"]{color:#a2aaa4}#board button[data-signal="3"]{color:#ffd978}#info{background:#142b30;padding:12px;border-radius:10px;font-family:ui-monospace,monospace;color:#cfefce}#controls button{background:#b88b52;color:#102a30;font-weight:700;border-color:#dec18a}