/* Chesschips — slate board, teal for book moves, amber for mistakes. */
:root{
  --bg:#F3F5F7; --surface:#FFFFFF; --ink:#18212B; --muted:#5E6B78; --line:#DCE2E8;
  --sq-light:#DDE5EC; --sq-dark:#7189A0;
  --accent:#0F766E; --accent-soft:#D7EFEC; --on-accent:#FFFFFF;
  --warn:#B45309; --warn-soft:#FBEBD5;
  --hl:rgba(250,204,21,.45); --bad:rgba(220,38,38,.5); --hint:rgba(15,118,110,.55); --view:rgba(99,102,241,.35);
  --pw:#FFFFFF; --pw-stroke:#1A222B; --pb:#141A21;
  --f-display:"Bricolage Grotesque",ui-sans-serif,system-ui,sans-serif;
  --f-body:"IBM Plex Sans",ui-sans-serif,system-ui,sans-serif;
  --f-mono:"IBM Plex Mono",ui-monospace,Menlo,monospace;
  --f-piece:"Noto Sans Symbols 2","Segoe UI Symbol","DejaVu Sans",serif;
  color-scheme:light;
}
@media (prefers-color-scheme: dark){:root{
  --bg:#11161C; --surface:#18202A; --ink:#E6ECF2; --muted:#93A1AF; --line:#2A3542;
  --sq-light:#A9B8C6; --sq-dark:#4E6479; --accent:#2DD4BF; --accent-soft:#123A37; --on-accent:#08201D;
  --warn:#F59E0B; --warn-soft:#3A2A12; color-scheme:dark}}

*{box-sizing:border-box}
html,body{margin:0}
body{background:var(--bg);color:var(--ink);font:15px/1.55 var(--f-body);
  padding-left:max(16px,env(safe-area-inset-left,0px));padding-right:max(16px,env(safe-area-inset-right,0px));padding-bottom:40px}
a{color:var(--accent)}
[hidden]{display:none!important}

.top{max-width:1040px;margin:0 auto;display:flex;align-items:center;justify-content:space-between;gap:12px;padding-block:16px}
.logo{font:700 24px/1 var(--f-display);color:var(--ink);text-decoration:none;letter-spacing:-.01em}
.logo span{color:var(--accent)}
.user{display:flex;gap:8px;align-items:center;font-size:14px}
.user .name{color:var(--muted)}

.guest{max-width:1040px;margin:0 auto 12px;padding:8px 12px;border-radius:8px;background:var(--warn-soft);font-size:14px}

main{max-width:1040px;margin:0 auto;display:grid;gap:20px}

.btn{font:500 14px var(--f-body);padding:8px 14px;border-radius:8px;border:1px solid var(--line);background:var(--surface);color:var(--ink);cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;gap:6px}
.btn:hover{border-color:var(--accent)}
.btn.primary{background:var(--accent);border-color:var(--accent);color:var(--on-accent)}
.btn.big{font-size:17px;padding:12px 22px;border-radius:10px}
.btn:disabled{opacity:.45;cursor:default}
.btn:focus-visible,.link:focus-visible,.card:focus-visible,.mv:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.link{background:none;border:0;padding:0;font:inherit;color:var(--accent);cursor:pointer;text-decoration:underline}

.crumbs{display:flex;flex-wrap:wrap;gap:6px;font-size:13px;color:var(--muted)}
.crumbs a{color:var(--muted)}
.crumbs span:not(:last-child)::after{content:"›";margin-left:6px}

h1{font:700 clamp(28px,5vw,40px)/1.1 var(--f-display);margin:0;letter-spacing:-.015em;text-wrap:balance}
h2{font:700 20px/1.25 var(--f-display);margin:0;text-wrap:balance}
.lead{color:var(--muted);margin:6px 0 0;max-width:60ch}
.label{font:600 11px var(--f-body);letter-spacing:.08em;text-transform:uppercase;color:var(--muted);margin:0 0 8px}

/* Home */
.hero{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,320px);gap:32px;align-items:center;padding-block:24px}
.hero h1{font-size:clamp(36px,7vw,64px)}
.hero .cta{margin-top:20px;display:flex;gap:10px;flex-wrap:wrap}
.hero .mini{container-type:inline-size;width:100%;max-width:320px;justify-self:center}
@media (max-width:720px){.hero{grid-template-columns:1fr}}

/* Cards */
.grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:12px}
.card{display:grid;gap:6px;align-content:start;text-align:left;padding:14px 16px;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--ink);cursor:pointer;font:inherit;text-decoration:none;min-width:0}
.card:hover{border-color:var(--accent)}
.card h3{font:600 17px/1.3 var(--f-body);margin:0}
.card p{margin:0;color:var(--muted);font-size:14px}
.card .meta{font:12px var(--f-mono);color:var(--muted);display:flex;gap:10px;flex-wrap:wrap}
.card .meta b{font-weight:500;color:var(--accent)}
.side-cards{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
@media (max-width:560px){.side-cards{grid-template-columns:1fr}}
.side-card{padding:22px;gap:10px}
.side-card .glyph{width:64px;height:64px}
.side-card h3{font:700 22px/1.2 var(--f-display)}
.main-line{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.status{font:12px var(--f-mono)}
.status.ok{color:var(--accent)}
.status.no{color:var(--muted)}

/* Trainer */
.trainer{display:grid;grid-template-columns:minmax(0,1.15fr) minmax(0,1fr);gap:24px;align-items:start}
@media (max-width:820px){.trainer{grid-template-columns:1fr}}
.stage{display:grid;gap:10px;min-width:0}
.boardbox{container-type:inline-size;width:100%;max-width:560px;justify-self:center}
.board{display:grid;grid-template-columns:repeat(8,1fr);grid-template-rows:repeat(8,1fr);aspect-ratio:1;max-width:100%;border-radius:6px;overflow:hidden;box-shadow:0 12px 30px -18px rgba(0,0,0,.45);user-select:none}
.board.review{box-shadow:0 0 0 3px var(--view),0 12px 30px -18px rgba(0,0,0,.45)}
.sq{position:relative;display:grid;place-items:center;cursor:pointer;border:0;padding:0;background:var(--sq-light);font:inherit}
.sq.d{background:var(--sq-dark)}
.sq:focus-visible{outline:3px solid var(--accent);outline-offset:-3px;z-index:2}
.sq::after{content:"";position:absolute;inset:0;pointer-events:none}
.sq.last::after{background:var(--hl)}
.sq.sel::after{background:var(--hl);box-shadow:inset 0 0 0 3px rgba(0,0,0,.25)}
.sq.bad::after{background:var(--bad)}
.sq.hint::after{background:var(--hint)}
.sq .dot{position:absolute;width:28%;height:28%;border-radius:50%;background:rgba(0,0,0,.22);z-index:1}
.sq .ring{position:absolute;inset:6%;border-radius:50%;box-shadow:inset 0 0 0 4px rgba(0,0,0,.22);z-index:1}
.co{position:absolute;font:500 2.1cqw/1 var(--f-mono);z-index:1;pointer-events:none;opacity:.8}
.co.r{top:4%;left:5%} .co.f{bottom:4%;right:6%}
.sq .co{color:var(--sq-dark)} .sq.d .co{color:var(--sq-light)}
.bar{display:flex;gap:8px;flex-wrap:wrap;justify-content:center}
.prog{height:4px;border-radius:2px;background:var(--line);overflow:hidden}
.prog i{display:block;height:100%;background:var(--accent);transition:width .3s}
.side{display:grid;gap:16px;min-width:0}
.title-block h1{font-size:clamp(22px,3.4vw,28px)}
.title-block p{margin:2px 0 0;color:var(--muted);font:13px var(--f-mono)}

.coach{border-radius:10px;padding:14px 16px;background:var(--surface);border:1px solid var(--line);min-height:118px;display:grid;gap:6px;align-content:start}
.coach.good h2{color:var(--accent)}
.coach.bad{background:var(--warn-soft);border-color:transparent}
.coach.bad h2{color:var(--warn)}
.coach.done{background:var(--accent-soft);border-color:transparent}
.coach.review{border-color:var(--view)}
.coach h2{font-size:18px}
.coach p{margin:0}
.coach .meta{font:12px var(--f-mono);color:var(--muted)}
.coach .row{display:flex;gap:8px;flex-wrap:wrap;margin-top:6px}

.notation{background:var(--surface);border:1px solid var(--line);border-radius:10px;padding:6px 8px;font:14px/1.5 var(--f-mono);font-variant-numeric:tabular-nums;
  display:grid;grid-template-columns:2.6em 1fr 1fr;column-gap:4px;row-gap:2px;align-content:start;
  max-height:240px;overflow-y:auto;overscroll-behavior:contain;scroll-behavior:smooth}
.notation .n{color:var(--muted);padding:3px 0}
.mv{font:inherit;text-align:left;background:none;border:0;border-radius:5px;padding:3px 6px;color:var(--ink);cursor:pointer}
.mv:hover{background:var(--accent-soft)}
.mv.cur{background:var(--view)}
.mv.miss{color:var(--warn)}
.mv.miss::after{content:" ?!";font-size:12px}
.notation .next{color:var(--muted);opacity:.5;padding:3px 6px}
.notehead{display:flex;justify-content:space-between;align-items:baseline;gap:8px}
.notehead .label{margin:0}
.notehead .keys{font:12px var(--f-mono);color:var(--muted)}

/* Profile */
.tablewrap{overflow-x:auto;border:1px solid var(--line);border-radius:10px;background:var(--surface)}
table{border-collapse:collapse;width:100%;font-size:14px}
th,td{text-align:left;padding:8px 12px;border-bottom:1px solid var(--line);white-space:nowrap}
th{font:600 11px var(--f-body);letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
tr:last-child td{border-bottom:0}
td.num{font-variant-numeric:tabular-nums;font-family:var(--f-mono)}
td.moves{white-space:normal;font:13px var(--f-mono);color:var(--muted);min-width:260px}
.empty{padding:20px;color:var(--muted);text-align:center}

/* Dialog */
dialog{border:1px solid var(--line);border-radius:12px;background:var(--surface);color:var(--ink);padding:20px;width:min(360px,calc(100vw - 32px))}
dialog::backdrop{background:rgba(10,15,20,.5)}
dialog form{display:grid;gap:8px}
dialog label{font-size:13px;color:var(--muted)}
dialog input{font:inherit;padding:8px 10px;border-radius:8px;border:1px solid var(--line);background:var(--bg);color:var(--ink)}
dialog input:focus-visible{outline:2px solid var(--accent);outline-offset:1px}
dialog .row{display:flex;gap:8px;margin-top:6px}
dialog .err{color:var(--warn);margin:0;font-size:14px}
dialog .switch{font-size:14px;margin:4px 0 0;color:var(--muted)}

@media (prefers-reduced-motion:reduce){*{transition:none!important;scroll-behavior:auto!important}}

/* Pieces (SVG) */
.pc{position:relative;z-index:1;width:88%;height:88%;pointer-events:none;user-select:none;-webkit-user-drag:none}

/* Board colour themes (same in light and dark mode, except Slate) */
:root[data-board="wood"],[data-board="wood"]{--sq-light:#F0D9B5;--sq-dark:#B58863}
:root[data-board="green"],[data-board="green"]{--sq-light:#EEEED2;--sq-dark:#769656}
:root[data-board="ice"],[data-board="ice"]{--sq-light:#E6EEF5;--sq-dark:#8FA9C3}
:root[data-board="sand"],[data-board="sand"]{--sq-light:#F2E6CF;--sq-dark:#C9A66B}
:root[data-board="rose"],[data-board="rose"]{--sq-light:#F3E1E4;--sq-dark:#B87884}
.sw[data-board="slate"]{--sq-light:#DDE5EC;--sq-dark:#7189A0}

/* Header settings button */
.topright{display:flex;align-items:center;gap:8px}
.iconbtn{display:grid;place-items:center;width:38px;height:38px;border-radius:8px;border:1px solid var(--line);background:var(--surface);color:var(--ink);cursor:pointer}
.iconbtn:hover{border-color:var(--accent)}
.iconbtn:focus-visible{outline:2px solid var(--accent);outline-offset:2px}

/* Settings dialog */
dialog.settings{width:min(520px,calc(100vw - 32px))}
.sethead{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:14px}
.settings .label{margin-top:12px}
.opts{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:8px}
.opt{display:grid;gap:6px;justify-items:center;padding:10px 6px;border-radius:10px;border:1px solid var(--line);background:var(--bg);color:var(--ink);font:500 13px var(--f-body);cursor:pointer}
.opt:hover{border-color:var(--accent)}
.opt.on{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.opt:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.pv{display:flex;gap:2px;background:var(--sq-light);border-radius:6px;padding:4px}
.pv img{width:36px;height:36px}
.sw{display:grid;grid-template-columns:repeat(2,22px);grid-template-rows:repeat(2,22px);border-radius:5px;overflow:hidden}
.sw i{background:var(--sq-light)} .sw i.d{background:var(--sq-dark)}
.credit{font-size:12px;color:var(--muted);margin:14px 0 0}
@media (max-width:420px){.opts{grid-template-columns:repeat(2,minmax(0,1fr))}}

/* Home: opening overview */
.board.static{pointer-events:none}
.board.static .sq{cursor:default}
.openings{display:grid;gap:14px;padding-top:8px}
.openings h2{font-size:24px}
.opgrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(320px,1fr));gap:14px}
@media (max-width:400px){.opgrid{grid-template-columns:1fr}}
.opcard{display:grid;grid-template-columns:140px minmax(0,1fr);gap:14px;padding:14px;border-radius:10px;border:1px solid var(--line);background:var(--surface);align-items:start}
.opboard{display:block;container-type:inline-size;width:100%}
.opboard .co{display:none}
.opinfo{min-width:0;display:grid;gap:4px}
.opinfo h3{margin:0;font:600 17px/1.3 var(--f-body)}
.opinfo h3 a{color:var(--ink);text-decoration:none}
.opinfo h3 a:hover{color:var(--accent)}
.opmoves{margin:0;font:13px var(--f-mono);color:var(--accent)}
.opmeta{margin:0;font-size:13px;color:var(--muted)}
.oplines{list-style:none;margin:4px 0 0;padding:0;display:grid;gap:2px;font-size:14px}
.oplines a{color:var(--ink)}
.oplines a:hover{color:var(--accent)}
.tag{font:11px var(--f-mono);color:var(--muted);border:1px solid var(--line);border-radius:4px;padding:0 4px}
.oplines a{text-decoration:none}
.oplines a:hover{text-decoration:underline}
.hero .lead{margin-top:14px}
.opgrid{grid-template-columns:repeat(2,minmax(0,1fr))}
@media (max-width:720px){.opgrid{grid-template-columns:1fr}}

/* Hero animated board */
figure.mini{margin:0;display:grid;gap:10px}
figure.mini a{display:block}
#heroCap{display:grid;gap:2px;min-height:4.6em}
#heroCap b{font:700 18px/1.25 var(--f-display)}
#heroCap span{font-size:13px;color:var(--muted)}
#heroCap .hmoves{font:13px/1.5 var(--f-mono);color:var(--accent)}
.opcard.previewing .opmoves{color:var(--ink)}
.oplines a:focus-visible{outline:2px solid var(--accent);outline-offset:2px;border-radius:3px}
/* Reserve two lines for the move text so hover previews don't shift the page */
.opmoves{line-height:1.5;min-height:3em;display:-webkit-box;-webkit-box-orient:vertical;-webkit-line-clamp:2;line-clamp:2;overflow:hidden}
/* Training mode tabs */
.tabs{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:4px;padding:4px;border-radius:10px;background:var(--surface);border:1px solid var(--line)}
.tab{text-align:center;padding:7px 4px;border-radius:7px;font:500 14px var(--f-body);color:var(--muted);text-decoration:none}
.tab:hover{color:var(--ink);background:var(--bg)}
.tab.on{background:var(--accent);color:var(--on-accent)}
.tab:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
.clock{font:500 20px/1 var(--f-mono);font-variant-numeric:tabular-nums;padding:8px 12px;border-radius:8px;background:var(--surface);border:1px solid var(--line);min-width:6.5ch;text-align:right;align-self:center}

/* Drag & drop */
#board{touch-action:none}
#board.dragging .sq{cursor:grabbing}
.sq.lifted .pc{opacity:.25}
.sq.over::after{box-shadow:inset 0 0 0 4px rgba(255,255,255,.65)}
img.ghost{position:fixed;left:0;top:0;z-index:50;pointer-events:none;filter:drop-shadow(0 6px 8px rgba(0,0,0,.35));will-change:transform}

/* Guest bar close + header badges */
.guest{display:flex;align-items:center;justify-content:space-between;gap:12px}
.guest .close{flex:none;width:28px;height:28px;border:0;border-radius:6px;background:transparent;color:var(--ink);font:400 22px/1 var(--f-body);cursor:pointer}
.guest .close:hover{background:rgba(0,0,0,.08)}
.guest .close:focus-visible{outline:2px solid var(--accent)}
.count{display:inline-grid;place-items:center;min-width:20px;height:20px;padding:0 6px;margin-left:6px;border-radius:10px;background:var(--accent);color:var(--on-accent);font:600 12px/1 var(--f-mono);font-variant-numeric:tabular-nums}
.btn.login{position:relative}
.btn.login .warn{position:absolute;top:-7px;right:-7px;display:grid;place-items:center;width:18px;height:18px;border-radius:50%;background:#DC2626;color:#fff;font:700 14px/1 var(--f-body);box-shadow:0 0 0 2px var(--bg)}

.guest.guest-wide{max-width:none;margin:0;padding:12px 16px;flex-wrap:wrap}

/* Opening page study sections and games */
.subhead{font-size:20px;margin-top:8px}
.study{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:20px}
@media (max-width:720px){.study{grid-template-columns:1fr}}
.study section,.gblock{min-width:0}
.study h2{margin-bottom:8px}
.bul{margin:0;padding-left:20px;display:grid;gap:6px;max-width:65ch}
.lead.small{font-size:14px;margin:4px 0 10px}
.muted{color:var(--muted)}
.games{list-style:none;margin:0 0 14px;padding:0;border:1px solid var(--line);border-radius:10px;background:var(--surface);overflow:hidden}
.games li+li{border-top:1px solid var(--line)}
.games a{display:flex;justify-content:space-between;gap:12px;flex-wrap:wrap;padding:9px 14px;color:var(--ink);text-decoration:none}
.games a:hover{background:var(--bg)}
.games .gm{color:var(--muted);font:13px var(--f-mono);font-variant-numeric:tabular-nums}
.notation.tall{max-height:420px}
.mv.book{color:var(--accent)}

/* Below the trainer: lines, plans, endgames, games */
.below{display:grid;gap:24px;margin-top:12px;padding-top:20px;border-top:1px solid var(--line)}
.below h2{margin-bottom:10px}
.linechips{display:grid;grid-template-columns:repeat(auto-fill,minmax(220px,1fr));gap:8px}
.chip{display:grid;gap:2px;padding:10px 12px;border-radius:10px;border:1px solid var(--line);background:var(--surface);color:var(--ink);text-decoration:none;min-width:0}
.chip:hover{border-color:var(--accent)}
.chip.on{border-color:var(--accent);box-shadow:inset 0 0 0 1px var(--accent)}
.chip b{font-weight:600;font-size:14px}
.chip span{font:12px var(--f-mono);color:var(--muted)}
.chip:focus-visible{outline:2px solid var(--accent);outline-offset:2px}
p.small{font-size:14px;margin:0}

/* Breadcrumbs */
.crumbs ol{list-style:none;margin:0;padding:0;display:flex;flex-wrap:wrap;align-items:center;gap:2px 0;font-size:14px}
.crumbs li{display:flex;align-items:center;min-width:0}
.crumbs li+li::before{content:"";width:6px;height:6px;margin:0 10px;border-top:1.5px solid var(--muted);border-right:1.5px solid var(--muted);transform:rotate(45deg);opacity:.6}
.crumbs a{color:var(--muted);text-decoration:none;padding:2px 0}
.crumbs a:hover{color:var(--accent);text-decoration:underline}
.crumbs [aria-current]{color:var(--ink);font-weight:600}
.crumbs span:not(:last-child)::after{content:none}

/* Half boards on the side cards */
.side-card{grid-template-rows:auto auto auto auto 1fr}
.halfboard{display:grid;grid-template-columns:repeat(8,1fr);grid-template-rows:repeat(4,1fr);aspect-ratio:2/1;max-width:100%;margin-top:10px;border-radius:6px;overflow:hidden;align-self:end}
.hsq{display:grid;place-items:center;background:var(--sq-light)}
.hsq.d{background:var(--sq-dark)}
.hsq img{width:86%;height:86%}

/* Mini boards on the opening cards */
.minib{container-type:inline-size;width:100%;margin-bottom:6px}
.minib .co{display:none}
.opcard-mini .opmoves{min-height:0;-webkit-line-clamp:1;line-clamp:1}

/* Deeper line toggle */
.deeptoggle{display:inline-flex;align-items:center;gap:8px;margin-top:8px;font-size:14px;cursor:pointer;user-select:none}
.deeptoggle input{width:16px;height:16px;accent-color:var(--accent);margin:0}
.deeptoggle small{color:var(--muted);font:12px var(--f-mono)}

.coach .row.end{justify-content:flex-end}
.coach .row.arming{pointer-events:none;opacity:.55;transition:opacity .2s}

/* Footer, static pages, opening intro */
.foot{max-width:1040px;margin:48px auto 0;padding-block:20px;border-top:1px solid var(--line);display:flex;flex-wrap:wrap;justify-content:space-between;gap:12px;font-size:14px;color:var(--muted)}
.foot nav{display:flex;gap:18px}
.foot a{color:var(--muted);text-decoration:none}
.foot a:hover{color:var(--accent);text-decoration:underline}
.page{max-width:70ch;display:grid;gap:12px}
.page h1{margin-bottom:4px}
.page h2{margin-top:10px}
.page p{margin:0}
.intro{max-width:65ch;margin:10px 0 0;line-height:1.6}
.seo-links{columns:2;max-width:640px}

/* About a line + topic tags */
.about p{max-width:70ch;line-height:1.6;margin:0}
.about h2{margin-bottom:8px}
.about p+p{margin-top:1em}

/* Log in / register pages */
.authform{display:grid;gap:8px;max-width:360px;margin-top:16px}
.authform label{font-size:13px;color:var(--muted)}
.authform input{font:inherit;padding:8px 10px;border-radius:8px;border:1px solid var(--line);background:var(--bg);color:var(--ink)}
.authform input:focus-visible{outline:2px solid var(--accent);outline-offset:1px}
.authform .row{display:flex;gap:8px;margin-top:6px}
.authform .err{color:var(--warn);margin:0;font-size:14px}
.authform .hint{margin:0;font-size:13px;color:var(--muted)}
.authform .switch{font-size:14px;margin:4px 0 0;color:var(--muted)}
.hp{position:absolute;left:-9999px;width:1px;height:1px;overflow:hidden}