:root{--check-ink:#13233a;--check-cream:#fff8eb;--check-red:#df3f4a;--check-red-dark:#8e1f31;--check-black:#17202c;--check-gold:#f4bd45;--check-teal:#087c7b;--check-panel:#ffffff}
*{box-sizing:border-box}
body{margin:0;background:radial-gradient(circle at 50% -10%,#fbefd1 0,#d9f0ed 35%,#0b777c 100%);color:var(--check-ink);min-height:100vh}
.skip-link{position:fixed;z-index:1000;left:1rem;top:-5rem;background:#fff;color:#111;padding:.8rem 1rem;border-radius:.7rem;font-weight:900}.skip-link:focus{top:1rem}
.checkers-page{width:min(1180px,calc(100% - 2rem));margin:0 auto;padding:1.4rem 0 4rem}
.game-hero{display:flex;align-items:center;justify-content:space-between;gap:1rem;padding:1.5rem 0 1rem}.eyebrow{margin:0;color:#075e61;font-weight:900;letter-spacing:.12em;text-transform:uppercase;font-size:.78rem}.game-hero h1{font-family:'Playfair Display',serif;font-size:clamp(2.25rem,6vw,4.8rem);line-height:.95;margin:.35rem 0;color:#12223a}.game-hero h1 span{color:var(--check-red)}.tagline{font-weight:700;font-size:1.05rem;margin:.7rem 0 0;color:#405269}.help-button,.action{min-height:48px;border:2px solid #c7d5d8;background:#fff;color:#14243a;border-radius:999px;padding:.7rem 1rem;font:800 .94rem Poppins,sans-serif;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center}.help-button:hover,.action:hover{transform:translateY(-2px);box-shadow:0 7px 15px rgba(0,0,0,.13)}
.game-settings,.match-card,.lower-grid>section{background:rgba(255,255,255,.94);border:1px solid rgba(255,255,255,.72);border-radius:24px;box-shadow:0 18px 45px rgba(16,54,64,.2)}
.game-settings{padding:1.15rem 1.25rem;display:grid;grid-template-columns:minmax(190px,.8fr) 2fr;gap:1.2rem;align-items:center;margin-bottom:1rem}.game-settings h2,.lower-grid h2{margin:0;font-family:'Playfair Display',serif}.game-settings p,.lower-grid p{margin:.3rem 0 0;color:#566579;font-weight:600}.mode-picker{display:grid;grid-template-columns:repeat(4,1fr);gap:.55rem}.mode-button{min-height:72px;border:2px solid #d4dde1;background:#fff;border-radius:16px;padding:.55rem;display:grid;grid-template-columns:auto 1fr;gap:0 .45rem;text-align:left;align-items:center;color:#16253b;cursor:pointer}.mode-button>span{grid-row:1/3;font-size:1.45rem}.mode-button strong,.mode-button small{display:block}.mode-button small{color:#667386}.mode-button.active{border-color:var(--check-teal);background:#e4f6f3;box-shadow:inset 0 0 0 1px var(--check-teal)}
.match-card{padding:1rem 1.2rem 1.3rem}.match-topline{display:grid;grid-template-columns:1fr auto 1fr;gap:.8rem;align-items:center}.player-card{border:2px solid #d6dfe2;border-radius:18px;padding:.7rem .8rem;display:flex;align-items:center;gap:.65rem;background:#fff}.player-card.black{justify-content:flex-end}.player-card.active{border-color:var(--check-gold);box-shadow:0 0 0 4px rgba(244,189,69,.25)}.player-card small,.round-state span{display:block;color:#657386;font-weight:900;font-size:.69rem;letter-spacing:.08em}.player-card strong{display:block}.right-name{text-align:right}.piece-count{margin-left:auto;font-weight:900;font-size:1.4rem}.black .piece-count{margin-left:0;margin-right:auto}.mini-piece{width:38px;height:38px;flex:0 0 auto;border-radius:50%;box-shadow:inset 0 -6px 8px rgba(0,0,0,.28),0 3px 5px rgba(0,0,0,.18)}.red-piece{background:radial-gradient(circle at 35% 28%,#ff8a8f,var(--check-red) 67%,var(--check-red-dark))}.black-piece{background:radial-gradient(circle at 35% 28%,#647284,#131b27 70%);border:2px solid #aab5c2}.round-state{text-align:center}.round-state strong{display:block;font-size:.85rem;margin-top:.15rem}
body.checkers-no-sound .arc-mute,body.checkers-no-sound .arc-gear{display:none!important}
.game-layout{display:grid;grid-template-columns:minmax(130px,1fr) auto minmax(130px,1fr);gap:1rem;align-items:center}.captured-panel{align-self:center;background:#f1f6f6;border:1px solid #d7e1e2;border-radius:16px;padding:1rem;text-align:center}.captured-panel h2{font:900 .78rem Poppins,sans-serif;text-transform:uppercase;letter-spacing:.07em;margin:0}.captured-panel p{font-weight:800;color:#5c6877;margin:.35rem 0 0}.board-area{text-align:center}.board-frame{--cell:min(8.2vw,64px);position:relative;display:inline-grid;grid-template-columns:24px auto 24px;grid-template-rows:24px auto 24px;background:#452d20;padding:5px;border-radius:14px;box-shadow:0 15px 28px rgba(37,28,23,.3)}.checkers-board{grid-column:2;grid-row:2;display:flex;flex-direction:column;border:3px solid #2b1b13}.board-row{display:flex}.file-labels{grid-column:2;display:grid;grid-template-columns:repeat(8,1fr);color:#ffe9bd;font-size:.7rem;font-weight:900;align-items:center}.file-labels.top{grid-row:1}.file-labels.bottom{grid-row:3}.rank-labels{grid-row:2;display:grid;grid-template-rows:repeat(8,1fr);color:#ffe9bd;font-size:.7rem;font-weight:900;align-items:center}.rank-labels.left{grid-column:1}.rank-labels.right{grid-column:3}.keyboard-hint{font-size:.8rem;color:#536274;font-weight:700;max-width:560px;margin:.65rem auto 0}.game-actions{display:flex;justify-content:center;flex-wrap:wrap;gap:.65rem;margin-top:1rem}.action.primary{background:var(--check-teal);border-color:var(--check-teal);color:#fff}.action.quiet{background:#f4f7f7}.action.danger{background:#b82f3d;border-color:#b82f3d;color:#fff}.action:disabled{opacity:.45;cursor:not-allowed;transform:none;box-shadow:none}.achievement{margin:.9rem auto 0;max-width:680px;background:#fff4c8;border:2px solid #e5ac27;border-radius:14px;padding:.75rem;text-align:center;font-weight:900}
.board-square{width:var(--cell);height:var(--cell);border:0;padding:0;display:flex;align-items:center;justify-content:center;position:relative;cursor:pointer}.board-square.light{background:#f4dfb8}.board-square.dark{background:#9d6545}.board-square:disabled{opacity:1;cursor:default}.board-square:focus-visible{z-index:5;outline:5px solid #1478c9;outline-offset:-5px}.board-square.last-move{box-shadow:inset 0 0 0 5px rgba(255,231,111,.72)}.board-square.selected{box-shadow:inset 0 0 0 6px #ffe16a}.board-square.legal-target{cursor:pointer}.checker-piece{width:76%;height:76%;border-radius:50%;position:relative;z-index:2;box-shadow:inset 0 -8px 12px rgba(0,0,0,.3),0 4px 6px rgba(0,0,0,.25)}.checker-piece.red{background:radial-gradient(circle at 35% 28%,#ff9197,var(--check-red) 68%,var(--check-red-dark));border:3px solid #8e1f31}.checker-piece.black{background:radial-gradient(circle at 35% 28%,#667586,#17202c 70%);border:3px solid #9aa7b5}.checker-piece.red::before{content:'';position:absolute;inset:22%;border:3px solid rgba(255,255,255,.55);border-radius:50%}.checker-piece.black::before{content:'';position:absolute;inset:23%;background:repeating-linear-gradient(45deg,transparent 0 4px,rgba(255,255,255,.27) 4px 7px);border-radius:50%}.checker-piece.king::after{content:'♛';position:absolute;inset:0;display:grid;place-items:center;color:#fff;font-size:clamp(1rem,4vw,2rem);text-shadow:0 2px 3px #000}.move-marker{width:32%;height:32%;position:absolute;z-index:3;background:#0c8d78;border:3px solid #fff;transform:rotate(45deg);box-shadow:0 0 0 3px #0c8d78}.capture-target .move-marker{width:50%;height:50%;border-radius:50%;background:transparent;border:6px solid #fff;box-shadow:0 0 0 5px #e75a24;transform:none}.history-side{display:inline-block;min-width:44px;font-size:.7rem;text-transform:uppercase;font-weight:900}.history-side.red{color:#a62135}.history-side.black{color:#17202c}
.stats-card{margin-top:1rem;padding:1.15rem;display:flex;justify-content:space-between;gap:1rem}.stats-card dl{display:grid;grid-template-columns:repeat(4,1fr);gap:.5rem;margin:0}.stats-card dl div{text-align:center;background:#eef5f5;border-radius:12px;padding:.6rem;min-width:72px}.stats-card dt{font-size:.66rem;text-transform:uppercase;font-weight:900;color:#60707e}.stats-card dd{margin:.1rem 0 0;font-size:1.45rem;font-weight:900}
.game-dialog{border:0;padding:0;border-radius:24px;max-width:min(540px,calc(100% - 2rem));box-shadow:0 30px 80px rgba(0,0,0,.35)}.game-dialog::backdrop{background:rgba(12,27,38,.7)}.dialog-inner{position:relative;padding:1.5rem 1.7rem 1.7rem;text-align:center}.dialog-inner h2{font:800 1.75rem 'Playfair Display',serif;margin:.2rem 0}.dialog-inner ol{text-align:left;line-height:1.55}.dialog-close{position:absolute;right:.7rem;top:.7rem;width:44px;height:44px;border-radius:50%;border:0;background:#edf2f3;font-size:1.5rem;cursor:pointer}.dialog-icon{font-size:2.8rem;margin:0}.result-actions{display:flex;gap:.65rem;justify-content:center;flex-wrap:wrap;margin-top:1rem}.sr-only{position:absolute!important;width:1px!important;height:1px!important;padding:0!important;margin:-1px!important;overflow:hidden!important;clip:rect(0,0,0,0)!important;white-space:nowrap!important;border:0!important}
@media(max-width:900px){.game-settings{grid-template-columns:1fr}.game-layout{grid-template-columns:1fr}.captured-panel{display:none}.board-area{overflow-x:auto;padding:.35rem}.board-frame{--cell:min(9vw,60px)}}
@media(max-width:620px){.checkers-page{width:min(100% - 1rem,1180px);padding-top:.5rem}.game-hero{align-items:flex-start}.tagline{font-size:.9rem}.help-button{padding:.6rem .75rem}.mode-picker{grid-template-columns:1fr 1fr}.match-card{padding:.7rem}.match-topline{grid-template-columns:1fr 1fr}.round-state{grid-column:1/-1;grid-row:2}.player-card{padding:.5rem}.mini-piece{width:32px;height:32px}.board-frame{--cell:calc((100vw - 80px)/8);grid-template-columns:19px auto 19px;grid-template-rows:19px auto 19px}.keyboard-hint{font-size:.74rem}.stats-card{display:block}.stats-card dl{margin-top:.8rem}.game-actions .action{flex:1 1 44%}}
@media(max-width:390px){.game-hero h1{font-size:2.15rem}.game-hero .tagline{display:none}.mode-button{min-height:66px}.board-frame{--cell:max(44px,calc((100vw - 68px)/8));grid-template-columns:17px auto 17px;grid-template-rows:17px auto 17px}.stats-card dl{grid-template-columns:1fr 1fr}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;animation-duration:.01ms!important;transition-duration:.01ms!important}}