/*
---
filename: chess.css
author: Jean-Yves Cornet
date_modified: 2026-07-21 19:01:22
version: 1.0.0
scope: core
---
*/

:root{color-scheme:dark;--ink:#e8f1ff;--muted:#8394b6;--night:#070b19;--panel:#0d152b;--cyan:#51e7ff;--violet:#9e7bff;--line:rgba(119,158,231,.2)}*{box-sizing:border-box}body{margin:0;min-height:100vh;background:radial-gradient(circle at 20% 5%,#192a59 0,transparent 31rem),radial-gradient(circle at 85% 90%,#231849 0,transparent 36rem),var(--night);color:var(--ink);font:15px/1.55 Inter,ui-sans-serif,system-ui,sans-serif}.app{max-width:1500px;margin:auto;padding:20px 28px 34px}.topbar{height:66px;display:flex;align-items:center;gap:20px;border-bottom:1px solid var(--line)}.brand{font-size:20px;font-weight:900;letter-spacing:.12em;text-decoration:none;color:var(--ink)}.brand span,.brand i{color:var(--cyan);font-style:normal}.tagline{margin-left:auto;color:var(--muted);letter-spacing:.08em;font-size:11px;text-transform:uppercase}.icon-button{width:42px;border-radius:50%;padding:0;font-size:13px}.layout{display:grid;grid-template-columns:minmax(0,1fr) 340px;gap:28px;align-items:center;min-height:calc(100vh - 120px)}.arena{position:relative;min-height:580px}.arena canvas{display:block;width:100%;height:min(76vw,790px);min-height:580px;cursor:crosshair;outline:0}.canvas-help{position:absolute;bottom:8px;left:12px;margin:0;color:var(--muted);font-size:12px}.panel{background:linear-gradient(145deg,rgba(20,33,67,.94),rgba(8,13,30,.94));border:1px solid var(--line);border-radius:22px;padding:27px;box-shadow:0 30px 80px #0006}.eyebrow{font-size:10px;letter-spacing:.18em;color:var(--cyan);font-weight:800;margin:0 0 7px}.panel h1{font-size:25px;line-height:1.15;margin:0 0 10px}.status{color:var(--muted);min-height:46px;margin:0}.clock-row{display:grid;grid-template-columns:1fr 1fr;gap:9px;margin:20px 0}.clock{padding:10px;border:1px solid var(--line);border-radius:10px;background:#071027}.clock.is-active{border-color:var(--cyan);box-shadow:inset 0 0 20px #51e7ff18}.clock span{display:block;color:var(--muted);font-size:9px;letter-spacing:.12em}.clock strong{font:700 23px ui-monospace,monospace}.actions{display:grid;grid-template-columns:1.4fr 1fr 1fr;gap:8px}button{font:inherit;font-weight:700;color:var(--ink);border:1px solid var(--line);background:#101b38;border-radius:9px;padding:10px 8px;cursor:pointer}button:hover,button:focus-visible{border-color:var(--cyan);outline:0}.primary{background:linear-gradient(110deg,#1d97bd,#6b4cdd);border-color:#62dbf0}.moves{margin-top:23px;border-top:1px solid var(--line);padding-top:16px}.moves>div{display:flex;align-items:center;justify-content:space-between}.moves h2{font-size:13px;margin:0;text-transform:uppercase;letter-spacing:.1em}.moves button{padding:3px 8px;font-size:11px}.moves ol{margin:10px 0 0;padding-left:30px;height:185px;overflow:auto;color:#cbd7ef;font-family:ui-monospace,monospace;font-size:12px}.moves li{padding:2px 0}.moves li::marker{color:var(--muted)}details{border-top:1px solid var(--line);padding-top:15px;color:var(--muted);font-size:12px}summary{cursor:pointer;color:var(--ink);font-weight:700}dialog{background:#101a36;color:var(--ink);border:1px solid var(--cyan);border-radius:16px;padding:22px;box-shadow:0 20px 80px #000}dialog::backdrop{background:#01030bb8}.promotion-choices{display:flex;gap:8px}.promotion-choices button{font-size:32px;width:65px}.promotion-choices small{display:block;font-size:10px;color:var(--muted)}@media(max-width:900px){.layout{grid-template-columns:1fr;align-items:start}.arena{min-height:400px}.arena canvas{min-height:400px;height:75vw}.panel{max-width:650px;margin:auto;width:100%}}@media(max-width:520px){.app{padding:10px 13px}.tagline{display:none}.topbar{height:52px}.brand{font-size:16px}.arena canvas{min-height:350px;height:95vw}.panel{padding:18px}.canvas-help{font-size:10px}}