@font-face{font-family:OpeningSystem;src:local('Inter'),local('SF Pro Text'),local('Roboto')}*{box-sizing:border-box}html{--page:#0c1020;--card:#191d43;--accent:#08c4cb;--text-accent:#08c4cb;--on-card:#fff;--on-accent:#101218;--ink:#f6f7fc;--muted:#b8c1d9;--card-muted:#ccd0e0;background:var(--page);color:var(--ink);font-family:OpeningSystem,system-ui,-apple-system,BlinkMacSystemFont,'Segoe UI',sans-serif;font-size:16px;line-height:1.5}body{margin:0}button,input,textarea,select{font:inherit}button,a,input,select,textarea{-webkit-tap-highlight-color:transparent}button,a{touch-action:manipulation}button{cursor:pointer}a{color:var(--text-accent);text-underline-offset:3px}button:focus-visible,a:focus-visible,input:focus-visible,textarea:focus-visible,select:focus-visible,summary:focus-visible{outline:3px solid var(--text-accent);outline-offset:4px}button:disabled{opacity:.42;cursor:not-allowed}h1,h2,h3,p{margin:0}h1{font-family:Georgia,'Times New Roman',serif;font-size:clamp(2rem,3.6vw,3.2rem);line-height:1.12;font-weight:500;letter-spacing:-.04em;white-space:pre-line}h2{font-size:1.2rem;line-height:1.3;letter-spacing:-.02em}h3{font-size:1rem;line-height:1.4}p{white-space:pre-line;overflow-wrap:anywhere}hr{border:0;border-top:1px solid currentColor;opacity:.16;margin:10px 0}.sidebar{width:230px;height:100dvh;position:fixed;left:0;top:0;z-index:20;padding:30px 18px;border-right:1px solid color-mix(in srgb,var(--ink) 10%,transparent);display:flex;flex-direction:column;gap:22px;background:var(--page)}.brand{display:flex;align-items:center;gap:11px;font-weight:700;color:var(--ink);text-decoration:none;font-size:1.14rem;letter-spacing:-.03em}.brand img{border-radius:12px}.brand-caption{font-size:.8rem;color:var(--muted);padding:0 8px}.sidebar-foot{margin-top:auto;font-size:.75rem;color:var(--muted);padding:8px}nav{display:flex;flex-direction:column;gap:7px}.nav-item{border:0;border-radius:12px;background:none;color:var(--muted);display:flex;align-items:center;gap:14px;min-height:50px;padding:12px 14px;text-align:left;font-weight:550}.nav-item.active{background:color-mix(in srgb,var(--text-accent) 12%,transparent);color:var(--text-accent)}.app-main{margin-left:230px;min-height:100dvh}.topbar{height:84px;display:flex;justify-content:space-between;align-items:center;padding:0 38px;border-bottom:1px solid color-mix(in srgb,var(--ink) 8%,transparent)}.topbar>div{display:flex;flex-direction:column;gap:3px}.topbar-overline{font-size:.62rem;font-weight:750;letter-spacing:.22em;color:var(--muted)}.topbar strong{font-size:.95rem}main{max-width:1240px;margin:auto;padding:34px 36px 60px;min-height:70dvh}.stack{display:flex;flex-direction:column;gap:20px;min-width:0}.row{display:flex;align-items:center;gap:12px;flex-wrap:wrap}.row>.stack{gap:5px;flex:1}.row>h2{flex:1}.card{padding:24px;border-radius:22px;background:var(--card);color:var(--on-card);border:1px solid color-mix(in srgb,var(--on-card) 11%,transparent);display:flex;flex-direction:column;gap:16px;min-width:0}.card .muted{color:var(--card-muted)}.card .button:not(.primary){color:var(--on-card);border-color:color-mix(in srgb,var(--on-card) 24%,transparent);background:color-mix(in srgb,var(--on-card) 5%,transparent)}.card h2{color:var(--on-card)}.card a{color:inherit}.hero{padding:34px;background:linear-gradient(130deg,color-mix(in srgb,var(--card) 93%,white),var(--card));gap:20px}.hero>p{max-width:650px;line-height:1.7}.eyebrow{color:var(--card-muted);font-size:.67rem;text-transform:uppercase;letter-spacing:.16em;font-weight:700}.muted{color:var(--muted);font-size:.88rem;line-height:1.6}.button{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;padding:11px 16px;border-radius:12px;border:1px solid color-mix(in srgb,var(--ink) 18%,transparent);background:transparent;color:var(--ink);text-decoration:none;line-height:1.35;font-size:.88rem;font-weight:600;transition:transform .14s ease,opacity .14s ease}.button:active:not(:disabled){transform:scale(.975)}.button.primary{background:var(--accent);color:var(--on-accent);border-color:transparent}.button svg{flex-shrink:0}.tag{display:inline-flex;align-items:center;max-width:100%;font-size:.72rem;line-height:1.35;font-weight:600;border-radius:100px;padding:7px 10px;background:color-mix(in srgb,var(--ink) 8%,transparent);color:inherit;overflow-wrap:anywhere}.card .tag{background:color-mix(in srgb,var(--on-card) 9%,transparent)}.opening-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(min(100%,265px),1fr));gap:16px}.opening-card{text-align:left;position:relative;min-height:230px;gap:14px;transition:transform .18s ease,box-shadow .18s ease}@media(hover:hover) and (pointer:fine){.opening-card:hover{transform:translateY(-3px);box-shadow:0 10px 30px #0002}}.opening-card h2{font-family:Georgia,serif;font-size:1.55rem;padding-right:55px}.opening-card .row:first-child{justify-content:space-between}.opening-piece{position:absolute;right:20px;top:76px;width:54px;height:54px;object-fit:contain}.opening-card .row:last-of-type{justify-content:space-between;margin-top:auto}.summary-grid{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:14px}.summary-grid .card{gap:7px}.big-number{font-size:clamp(1.7rem,3vw,2.4rem);font-weight:650;line-height:1.15;letter-spacing:-.05em}.score-cards{display:grid;grid-template-columns:1fr 1fr;gap:16px}.score-cards .card{gap:8px}.segmented{display:flex;flex-wrap:wrap;background:color-mix(in srgb,var(--ink) 7%,transparent);border:1px solid color-mix(in srgb,var(--ink) 12%,transparent);border-radius:12px;padding:4px;gap:3px}.segmented button{border:0;border-radius:8px;min-width:80px;min-height:40px;padding:6px 15px;background:none;color:var(--muted);font-size:.87rem;font-weight:600}.segmented .selected{background:var(--text-accent);color:var(--page)}input:not([type=checkbox]):not([type=color]),textarea,select{width:100%;border:1px solid color-mix(in srgb,var(--ink) 25%,transparent);background:var(--page);color:var(--ink);border-radius:11px;padding:12px 14px;min-height:46px;max-width:100%}input[type=search]{padding:15px 18px}textarea{min-height:160px;resize:vertical;font-family:ui-monospace,SFMono-Regular,Consolas,monospace;font-size:.82rem}.field{display:flex;flex-direction:column;gap:7px;font-size:.87rem;font-weight:550}.field input[type=color]{width:100%;height:46px;border:1px solid color-mix(in srgb,var(--on-card) 20%,transparent);border-radius:9px;background:var(--page)}/* Visible switches use spans rather than input pseudo-elements. */
.toggle{--toggle-ink:var(--ink);--toggle-surface:var(--page);display:flex;justify-content:space-between;align-items:center;gap:16px;font-size:.9rem;min-height:44px;cursor:pointer}
.card .toggle{--toggle-ink:var(--on-card);--toggle-surface:var(--card)}
.toggle>span:first-child{min-width:0;overflow-wrap:anywhere}
.switch-control{position:relative;display:inline-flex;align-items:center;justify-content:center;flex:0 0 52px;width:52px;height:44px}
.toggle .switch-input{position:absolute;inset:0;z-index:1;appearance:none;-webkit-appearance:none;width:100%;height:100%;margin:0;opacity:0;cursor:pointer}
.switch-track{position:relative;display:block;box-sizing:border-box;width:52px;height:30px;border:1px solid var(--toggle-ink);border-radius:999px;background:color-mix(in srgb,var(--toggle-ink) 12%,var(--toggle-surface));pointer-events:none;transition:background-color .16s ease}
.switch-thumb{position:absolute;left:3px;top:3px;width:22px;height:22px;border-radius:50%;background:var(--toggle-ink);transition:transform .16s ease,background-color .16s ease}
.switch-input:checked+.switch-track{background:var(--toggle-ink)}
.switch-input:checked+.switch-track .switch-thumb{transform:translateX(22px);background:var(--toggle-surface)}
.switch-input:focus-visible+.switch-track{outline:3px solid var(--toggle-ink);outline-offset:4px}
.switch-input:disabled+.switch-track{opacity:.45}
.training-layout{display:grid;grid-template-columns:minmax(270px,1.05fr) minmax(280px,1fr);gap:24px;align-items:start}.training-layout>.stack{gap:16px}.session-title{font-size:2rem}.board-with-eval{display:flex;gap:9px;width:100%;align-items:stretch}.board-column{width:100%;max-width:580px;margin-inline:auto}.board{position:relative;width:100%;aspect-ratio:1;overflow:hidden;border-radius:12px;background:var(--light-square);direction:ltr;user-select:none;-webkit-user-select:none;touch-action:pan-y;isolation:isolate}.squares{display:grid;grid-template-columns:repeat(8,1fr);width:100%;height:100%;position:absolute;inset:0}.square{min-width:0;position:relative;border:0;border-radius:0;padding:0;background:var(--light-square);color:var(--dark-square);aspect-ratio:1;touch-action:pan-y}.square.dark{background:var(--dark-square);color:var(--light-square)}.board[data-material=wood] .square:before,.board[data-material=marble] .square:before{content:'';position:absolute;inset:0;background-image:url('pieces/board-grain.png');background-size:220px;opacity:.17;pointer-events:none}.board[data-material=marble] .square:before{background-image:url('pieces/board-marble.png');opacity:.15}.square.last{box-shadow:inset 0 0 0 100px #ebce3e55}.square.selected{box-shadow:inset 0 0 0 100px #e6cc36aa}.square.destination:after{content:'';position:absolute;width:25%;height:25%;border-radius:50%;background:#101d2855;top:37.5%;left:37.5%;z-index:1}.square.hinted:after{content:'';position:absolute;inset:6%;border-radius:50%;border:4px solid #27be61;z-index:3;background:#27be611b}.square:focus-visible{outline:3px solid #0d2b5e;outline-offset:-4px;z-index:5}.rank,.file{position:absolute;font-size:clamp(8px,1.25vw,12px);font-weight:700;z-index:2;line-height:1;pointer-events:none}.rank{left:3px;top:3px}.file{bottom:3px;right:3px}.pieces{position:absolute;inset:0;pointer-events:none;z-index:2}.piece{position:absolute;top:0;left:0;width:12.5%;height:12.5%;object-fit:contain;will-change:transform;pointer-events:none;filter:drop-shadow(0 1px 1px #0003)}.piece.dragging{z-index:6;filter:drop-shadow(0 6px 5px #0006);scale:1.07}.board-overlay{position:absolute;inset:0;width:100%;height:100%;pointer-events:none;z-index:4}.evaluation{position:relative;overflow:hidden;width:27px;min-width:27px;border-radius:6px;background:#252834;display:flex;flex-direction:column;justify-content:flex-end;color:#111}.eval-white{background:#f4f4ef;width:100%;transition:height .25s}.evaluation.reverse{justify-content:flex-start}.evaluation span{position:absolute;bottom:7px;left:0;right:0;text-align:center;font-size:.64rem;font-weight:750;background:#f4f4efcc;padding:5px 0;overflow:hidden}.evaluation.reverse span{bottom:auto;top:7px}.coach-text{line-height:1.75;font-size:.94rem}.notation{font-family:ui-monospace,SFMono-Regular,monospace;font-size:.85rem;line-height:1.9}.success-mark{width:40px;height:40px;border-radius:50%;background:var(--accent);color:var(--on-accent);display:grid;place-items:center}progress{appearance:none;width:100%;height:5px;border:0;border-radius:10px;overflow:hidden;background:color-mix(in srgb,var(--ink) 12%,transparent)}progress::-webkit-progress-bar{background:color-mix(in srgb,var(--ink) 12%,transparent)}progress::-webkit-progress-value{background:var(--accent);border-radius:10px}progress::-moz-progress-bar{background:var(--accent)}.score-graph{display:block;width:100%;height:130px;cursor:crosshair;overflow:visible;color:var(--card-muted)}details>summary{cursor:pointer;font-size:.9rem;font-weight:600;min-height:32px;padding-block:3px}details>summary~*{margin-top:16px}.move-list{display:grid;grid-template-columns:1fr 1fr;gap:6px}.move-list button{display:flex;justify-content:space-between;align-items:center;gap:10px;background:transparent;color:var(--on-card);border:1px solid transparent;border-radius:8px;text-align:left;padding:10px;min-height:44px;font-size:.78rem}.move-list button.active{border-color:var(--accent);background:color-mix(in srgb,var(--on-card) 8%,transparent)}.warning{color:#f6b13c}.progress-row{display:flex;align-items:center;justify-content:space-between;gap:15px;padding-block:10px;border-top:1px solid color-mix(in srgb,var(--on-card) 10%,transparent)}.progress-row .stack{gap:2px}.progress-row strong{font-size:.85rem}.swatches{display:flex;gap:12px;flex-wrap:wrap}.swatch{width:42px;height:42px;border-radius:50%;border:2px solid #fff5;color:#111;font-weight:700;font-size:1.2rem}.preview-board{max-width:360px;align-self:center}.dialog{background:var(--page);color:var(--ink);border:1px solid color-mix(in srgb,var(--ink) 20%,transparent);border-radius:22px;width:min(680px,calc(100% - 28px));padding:24px;max-height:85dvh;box-shadow:0 30px 100px #0006}.dialog>*+*{margin-top:16px}.dialog-heading{display:flex;align-items:center;justify-content:space-between;gap:16px}.dialog-heading h2{font-size:1.4rem}.dialog-heading .button{padding:8px;min-width:42px}.dialog::backdrop{background:#030818aa;backdrop-filter:blur(4px)}.skip-link{position:fixed;top:-60px;left:16px;z-index:100;background:var(--accent);color:var(--on-accent);padding:12px 20px;border-radius:10px}.skip-link:focus{top:12px}.storage-warning{padding:0 30px 25px;color:#c98534;font-size:.8rem}#toast{position:fixed;bottom:24px;left:250px;right:20px;z-index:100;display:flex;justify-content:center;pointer-events:none}.toast{max-width:700px;padding:14px 20px;border-radius:12px;background:var(--accent);color:var(--on-accent);box-shadow:0 8px 40px #0003;font-size:.9rem}.toast.error{background:#5b252a;color:#fff}.boot-error{max-width:650px;padding:60px 24px}.boot-error>*+*{margin-top:22px}[hidden]{display:none!important}@media(min-width:1100px){.training-layout>.stack:first-child{position:sticky;top:24px}}@media(max-width:850px){.sidebar{position:fixed;inset:auto 0 0;width:100%;height:auto;padding:0 8px max(6px,env(safe-area-inset-bottom));border-right:0;border-top:1px solid color-mix(in srgb,var(--ink) 12%,transparent);background:var(--page)}.sidebar .brand,.brand-caption,.sidebar-foot{display:none}nav{flex-direction:row;justify-content:space-around;gap:0}.nav-item{flex:1;flex-direction:column;justify-content:center;gap:4px;font-size:.64rem;min-width:0;min-height:65px;padding:8px 2px;border-radius:0;line-height:1.15;text-align:center}.nav-item svg{height:21px;width:21px}.nav-item.active{background:none}.nav-item.active svg{filter:drop-shadow(0 0 8px color-mix(in srgb,var(--text-accent) 30%,transparent))}.app-main{margin-left:0}.topbar{height:72px;padding:0 22px}.topbar-overline{font-size:.58rem}main{padding:24px 20px calc(105px + env(safe-area-inset-bottom))}.hero{padding:26px}.training-layout{grid-template-columns:1fr 1fr;gap:18px}.training-layout>.stack{position:static}#toast{left:16px;right:16px;bottom:calc(82px + env(safe-area-inset-bottom))}.rank,.file{font-size:10px}}@media(max-width:650px){main{padding-inline:16px}.stack{gap:18px}.training-layout{grid-template-columns:1fr;gap:22px}.card{padding:20px;border-radius:19px}.hero{padding:26px 22px}.hero h1{font-size:2.15rem}.opening-grid{grid-template-columns:1fr}.opening-card{min-height:205px}.opening-card h2{font-size:1.6rem}.summary-grid{gap:9px}.summary-grid .card{padding:16px 11px}.summary-grid .muted{font-size:.73rem}.summary-grid .big-number{font-size:1.8rem}.score-cards{gap:10px}.score-cards .card{padding:18px 15px}.board-column{max-width:480px}.session-title{font-size:1.8rem}.move-list{grid-template-columns:1fr}.dialog{padding:20px}.button{padding:11px 13px}.coach-text{font-size:.95rem}.tag{font-size:.7rem}}@media(prefers-reduced-motion:reduce){*,*:before,*:after{scroll-behavior:auto!important;animation:none!important;transition:none!important}.opening-card:hover{transform:none}.button:active{transform:none}}@media print{.sidebar,.topbar,#toast{display:none}.app-main{margin:0}main{padding:0}}

.license-text{white-space:pre-wrap;overflow-wrap:anywhere;font:13px/1.6 monospace;}

/* Limit repaint to each library surface; do not create a GPU layer per card. */
.hero,.opening-card{isolation:isolate;contain:paint}
.hero{flex-shrink:0}
.opening-card{appearance:none;-webkit-appearance:none;align-self:stretch;width:100%;height:auto}
.opening-card>*,.hero>*{flex-shrink:0}
.swatch{position:relative;display:inline-flex;align-items:center;justify-content:center}
.swatch[aria-pressed=true]{outline:2px solid var(--on-card);outline-offset:3px}
.swatch-mark{display:inline-grid;place-items:center;width:24px;height:24px;line-height:1;border-radius:50%;background:var(--page);color:var(--ink);font-size:1rem}