:root{font-family:Inter,system-ui,sans-serif;color:#eaf0ff;background:#0a1326;font-synthesis:none}*{box-sizing:border-box}body{margin:0}header{display:flex;align-items:center;justify-content:space-between;gap:20px;max-width:1220px;margin:auto;padding:28px 32px;border-bottom:1px solid #24324c}.brand{display:flex;align-items:center;gap:12px;color:inherit;text-decoration:none;font-size:1.35rem;font-weight:750;letter-spacing:.06em}.brandmark{background:#315ed0;padding:12px 15px;border-radius:12px;color:#fff}.brand-sub{display:block;font-size:.75rem;letter-spacing:.13em;color:#aebbd7;margin-top:5px}.tagline{color:#bdc9e2;font-size:.9rem}main{max-width:1220px;margin:auto;padding:32px;display:grid;grid-template-columns:minmax(0,1fr) 320px;gap:32px}.game-heading{display:flex;align-items:center;justify-content:space-between;gap:15px;margin-bottom:20px}.eyebrow{font-size:.75rem;font-weight:650;letter-spacing:.15em;color:#91aaf0}h1{font-size:clamp(1.3rem,2.8vw,1.9rem);letter-spacing:-.035em;margin:8px 0;font-weight:650}h2{font-size:1.1rem;font-weight:650;margin:12px 0}.pill{font-size:.75rem;color:#bdcbef;border:1px solid #354666;padding:6px 10px;border-radius:30px;white-space:nowrap}.player{display:flex;align-items:center;gap:12px;padding:12px 0}.player small{display:block;color:#9dafcf;font-size:.8rem;margin-top:3px}.avatar{display:grid;place-items:center;background:#293958;width:36px;height:36px;border-radius:9px;font-weight:700}.avatar.white{background:#dbe5fa;color:#14264d}.side-piece{margin-left:auto;font-size:1.6rem}#chess-board{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));width:100%;aspect-ratio:1;border:6px solid #293f6c;border-radius:8px;overflow:hidden;box-shadow:0 15px 40px #0004}.square{position:relative;aspect-ratio:1;padding:0;border:0;border-radius:0;display:flex;align-items:center;justify-content:center;background:#e5eaf5;color:#253d67;cursor:pointer}.square.dark{background:#7893c0}.square.selected{box-shadow:inset 0 0 0 4px #e5b64f;background:#cbbd84}.square.legal:after{content:'';width:23%;height:23%;border-radius:50%;background:#14294c88;position:absolute;pointer-events:none}.square.capture:after{width:84%;height:84%;border:4px solid #17386f;background:transparent}.square:focus-visible{outline:4px solid #ffcf5c;outline-offset:-4px;z-index:1}.piece{width:78%;height:78%;overflow:visible;pointer-events:none}.coord{position:absolute;bottom:2px;left:4px;font-size:12px;font-weight:600}aside{padding-top:7px;display:flex;flex-direction:column;gap:16px}.panel{padding:22px;background:#131f36;border:1px solid #2c3b57;border-radius:14px}.panel p{font-size:.9rem;color:#b8c6df;line-height:1.6}.panel label{display:block;font-size:.875rem;color:#c1cee5;margin:17px 0 7px}select{display:block;width:100%;font:inherit;font-size:1rem;color:#eaf0ff;background:#1b2b48;border:1px solid #3c5075;padding:11px;border-radius:8px}button{font:inherit;color:#eaf0ff;background:#213452;border:1px solid #3e537b;padding:10px 14px;border-radius:8px;cursor:pointer}.actions{display:flex;flex-wrap:wrap;gap:8px;margin-top:20px}.primary{background:#315ed0;border-color:#315ed0}button:disabled{opacity:.45;cursor:default}button:hover:not(:disabled):not(.square){filter:brightness(1.15)}#chess-history{font-size:.9rem;color:#bac9e5;line-height:1.9;max-height:180px;overflow:auto;overflow-wrap:anywhere;font-variant-numeric:tabular-nums}summary{cursor:pointer;font-size:.95rem;font-weight:600}footer{max-width:1220px;margin:0 auto;padding:20px 32px 32px;color:#93a6ca;font-size:.8rem;display:flex;justify-content:space-between;gap:15px}@media(max-width:850px){main{grid-template-columns:1fr;max-width:680px;padding:20px}aside{display:grid;grid-template-columns:1fr 1fr}.panel:first-child{grid-row:span 2}header{padding:20px}.tagline{display:none}.panel{padding:16px}}@media(max-width:540px){aside{display:flex}.pill{display:none}header{padding:16px}.brand{font-size:1.1rem}.brand-sub{font-size:.7rem}main{padding:12px;gap:18px}.coord{font-size:11px}footer{padding:20px 16px;flex-direction:column}#chess-board{border-width:4px}}
[hidden]{display:none!important}.course-nav{max-width:1220px;margin:auto;display:flex;gap:8px;flex-wrap:wrap;padding:20px 32px 0}.course-nav button[aria-current=page]{background:#315ed0}.course-nav #new-learner{margin-left:auto}.training-shell,.certificate-shell{max-width:1220px;margin:auto;padding:28px 32px}.course-heading{display:flex;justify-content:space-between;align-items:center;gap:24px;margin-bottom:24px}.course-heading p{color:#b8c6df}.course-heading label{font-size:.875rem}progress{display:block;width:230px;height:12px;margin-top:10px;accent-color:#789eff}.course-layout{display:grid;grid-template-columns:260px minmax(0,1fr);gap:24px}#lesson-list{display:flex;flex-direction:column;gap:7px}#lesson-list button{text-align:left;font-size:.9rem}#lesson-list button[aria-current=step]{background:#315ed0}#lesson-list button:disabled{opacity:.55}.lesson h2{font-size:1.5rem}.lesson p{font-size:1rem;max-width:66ch}.lesson h3{font-size:1.05rem}#lesson-board{display:grid;grid-template-columns:repeat(8,1fr);max-width:280px;aspect-ratio:1;margin:20px auto;border:4px solid #355487}.lesson-square{display:flex;align-items:center;justify-content:center;position:relative;background:#e5eaf5;color:#172b4d;font-family:DejaVu Sans,serif;font-size:28px;line-height:1}.lesson-square.dark{background:#7893c0}.lesson-square.target{box-shadow:inset 0 0 0 3px #956710;background:#edcc77}.lesson-square.white-piece{color:#fff;text-shadow:1px 1px #10284b,-1px -1px #10284b}#lesson-answers{display:flex;flex-direction:column;gap:8px}#lesson-answers button{text-align:left;padding:12px}#lesson-answers button[aria-pressed=true]{background:#315ed0;border-color:#94b0ff}#lesson-feedback{min-height:1.5em;color:#f1d587}.certificate-shell{max-width:1000px}#certificate-form input{display:block;width:100%;max-width:460px;padding:12px;font:inherit;margin:8px 0 18px;background:#1b2b48;color:#fff;border:1px solid #60769d;border-radius:8px}#certificate-paper{background:#fff;color:#193565;border:12px double #264c96;padding:48px 35px;text-align:center;min-height:540px}.certificate-top{font-size:1.7rem;letter-spacing:.12em;font-weight:750}.certificate-top span{font-size:.8rem}.certificate-rule{height:2px;background:#bd9652;width:90px;margin:24px auto}.certificate-kicker{letter-spacing:.18em;font-size:.85rem}#certificate-paper h1{font-family:Georgia,serif;font-size:2rem}#certificate-name{font-size:2.5rem;font-family:Georgia,serif;margin:28px 0;overflow-wrap:anywhere}#certificate-paper p{line-height:1.8}.certificate-bottom{display:flex;justify-content:space-around;gap:25px;margin-top:40px}.certificate-bottom small{display:block;margin-top:8px}.certificate-meta{font-size:.8rem;color:#506280}@media(max-width:750px){.course-heading{display:block}.course-layout{grid-template-columns:1fr}#lesson-list{display:grid;grid-template-columns:1fr 1fr}#lesson-list button{font-size:.8rem;padding:9px}.training-shell,.certificate-shell{padding:20px 12px}.course-nav{padding:16px 12px 0}.course-nav #new-learner{margin-left:0}.course-nav button{font-size:.875rem}#certificate-paper{padding:30px 14px}#certificate-name{font-size:2rem}.certificate-bottom{flex-direction:column}progress{width:100%}}@media print{@page{size:landscape;margin:12mm}body{background:#fff}body>*:not(#certificate){display:none!important}#certificate{display:block!important;padding:0;max-width:none}#certificate-form,#certificate-actions{display:none!important}#certificate-paper{display:block!important;min-height:0;padding:22px;border:9px double #264c96;print-color-adjust:exact;-webkit-print-color-adjust:exact;break-inside:avoid}#certificate-paper h1{font-size:26px}#certificate-name{font-size:32px;margin:20px 0}.certificate-bottom{flex-direction:row;margin-top:24px}.certificate-rule{margin:14px auto}}
.coordinate-board{display:grid;grid-template-columns:28px minmax(0,1fr) 28px;grid-template-rows:28px auto 28px;gap:0;background:#172b4b;border-radius:10px;padding:3px}.coordinate-files{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));align-items:center;text-align:center;color:#f5f8ff;font-size:1rem;font-weight:650}.coordinate-ranks{display:grid;grid-template-rows:repeat(8,minmax(0,1fr));align-items:center;text-align:center;color:#f5f8ff;font-size:1rem;font-weight:650}.coordinate-files.top{grid-column:2;grid-row:1}.coordinate-files.bottom{grid-column:2;grid-row:3}.coordinate-ranks.left{grid-column:1;grid-row:2}.coordinate-ranks.right{grid-column:3;grid-row:2}.coordinate-board #chess-board,.coordinate-board #lesson-board{grid-column:2;grid-row:2;margin:0;max-width:none;border:0;border-radius:0;box-shadow:none}.lesson-coordinates{max-width:340px;margin:20px auto}.coordinate-key{font-size:.875rem!important;color:#c7d6f1!important}@media(max-width:540px){.coordinate-board{grid-template-columns:24px minmax(0,1fr) 24px;grid-template-rows:26px auto 26px}.coordinate-files,.coordinate-ranks{font-size:.875rem}}
.account-entry{max-width:980px;margin:35px auto;display:grid;grid-template-columns:1fr 1fr;gap:40px;padding:24px 32px}.account-intro{align-self:center}.account-intro h1{font-size:2.3rem}.account-intro p{line-height:1.7;color:#b8c6df}.account-intro a{color:#a9bfff}input{display:block;width:100%;font:inherit;color:#eaf0ff;background:#1b2b48;border:1px solid #61749a;padding:12px;border-radius:8px;margin:8px 0 14px}.panel form button{margin-top:15px}.panel small,.account-help{color:#b8c6df;font-size:.875rem}.dashboard-shell{max-width:1220px;margin:auto;padding:28px 32px}.dashboard-cards{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:18px;margin:22px 0}.dashboard-value{font-size:2.2rem}.dashboard-shell details{max-width:650px}#account-feedback,#password-feedback{color:#f1d587;line-height:1.5}@media(max-width:700px){.account-entry{grid-template-columns:1fr;margin:12px auto;padding:16px;gap:20px}.account-intro h1{font-size:1.8rem}.dashboard-shell{padding:20px 12px}.dashboard-cards{grid-template-columns:1fr}}
.admin-link{color:#b8ceff}.admin-table-wrap{overflow-x:auto;margin:20px 0}.admin-table{width:100%;border-collapse:collapse;font-size:.9rem;text-align:left}.admin-table th,.admin-table td{padding:14px 12px;border-bottom:1px solid #304366}.admin-table th{color:#b8c8e5;font-weight:600}.admin-table button{font-size:.85rem;white-space:nowrap}#admin-status{color:#f1d587}#reset-result{margin-top:24px;max-width:600px}
#try-chess{margin:12px 0}.trial-banner{grid-column:1/-1;display:flex;align-items:center;justify-content:space-between;gap:12px;flex-wrap:wrap;padding:14px 18px;background:#1d3764;border:1px solid #557fc6;border-radius:12px}.trial-banner strong{font-variant-numeric:tabular-nums;color:#ffe5a1;font-size:1.1rem}
aside .account-entry{display:block;margin:0;padding:0;max-width:none}aside .account-intro{margin-bottom:16px}aside .account-intro h2{margin:8px 0;font-size:1.25rem}aside .account-intro p{font-size:.9rem;margin:10px 0}aside .account-entry .panel{padding:18px}aside .account-entry .actions{margin-top:0}aside .account-intro .eyebrow{font-size:.7rem}aside .account-intro a{font-size:.875rem}@media(max-width:850px){aside:has(.account-entry:not([hidden])){display:flex}}
.engine-credit{font-size:.75rem;color:#9dafcf;line-height:1.6}.engine-credit a{color:#b8ceff}#online-status{color:#f1d587;overflow-wrap:anywhere}#online-panel{border-bottom:1px solid #3c5075;padding-bottom:16px;margin-top:16px}#online-link{font-size:.8rem}