:root{color-scheme:dark;font-family:Inter,ui-sans-serif,system-ui,sans-serif;background:#101917;color:#e9f0df}*{box-sizing:border-box}body{margin:0}main{max-width:1100px;margin:auto;padding:42px 28px}header{display:flex;align-items:center;justify-content:space-between;gap:20px;border-bottom:1px solid #34433b;padding-bottom:24px}.eyebrow{font-size:11px;letter-spacing:3px;color:#acbea9}h1{font-size:clamp(30px,5vw,50px);letter-spacing:-2px;margin:8px 0}h1 span{color:#c5e98b}h2{font-size:20px;margin:0 0 8px}p{color:#aebdaf;line-height:1.6}button{font:inherit;cursor:pointer;color:inherit}button:focus-visible,summary:focus-visible{outline:3px solid #e5f7a2;outline-offset:5px}.badge{border:1px solid #53624c;border-radius:30px;padding:9px 14px;font-size:12px;color:#c5e98b}.layout{display:grid;grid-template-columns:1fr 1.12fr;gap:60px;padding-top:34px}.boardtop{display:flex;justify-content:space-between;align-items:center;margin-bottom:20px}.count{font-variant-numeric:tabular-nums;color:#d2ecaa}.grid{display:grid;grid-template-columns:repeat(4,1fr);gap:12px;background:#0b1210;padding:20px;border:1px solid #34433b;border-radius:20px}.cell{aspect-ratio:1;border-radius:14px;border:1px solid #3b4c43;background:#202f28;position:relative;transition:background .2s,box-shadow .2s}.cell.lit{background:#d2ed9d;border-color:#e8ffc3;box-shadow:0 0 18px #c2ee7920;color:#26361f}.cell:after{content:'';display:block;width:14px;height:14px;border:2px solid #617260;border-radius:50%;margin:auto}.cell.lit:after{background:#698742;border-color:#698742}.cell.selected{outline:3px solid #f3c589;outline-offset:3px}.coord{position:absolute;left:9px;top:6px;font-size:10px;opacity:.65}.actions{display:flex;gap:10px;margin-top:18px}.plain{border:1px solid #46564a;background:transparent;border-radius:8px;padding:9px 14px}.plain:hover{background:#29392c}.rules{display:grid;gap:10px}.rule{width:100%;display:flex;align-items:center;text-align:left;gap:13px;border:1px solid #3b4b40;background:#19251f;border-radius:12px;padding:15px}.rule.on{border-color:#899f63;background:#243422}.rule.could{box-shadow:inset 3px 0 #f3c589}.num{font-size:12px;color:#9faf99;align-self:flex-start;padding-top:4px}.rule strong{font-size:14px}.desc{font-size:12px;line-height:1.5;color:#aebdaf;display:block;margin-top:4px}.switch{margin-left:auto;flex-shrink:0;width:46px;height:25px;border-radius:20px;background:#3d4b41;position:relative}.switch:before{content:'';position:absolute;width:17px;height:17px;background:#c4cdc0;left:4px;top:4px;border-radius:50%;transition:transform .15s}.on .switch{background:#a5c471}.on .switch:before{transform:translateX(21px);background:#172315}.state{font-size:10px;display:block;color:#d6eac0;margin-top:3px}.inspect{margin-top:22px;padding:18px;background:#19251f;border:1px solid #35463a;border-radius:12px;min-height:150px}.inspect p{font-size:13px;margin:7px 0}.tag{display:inline-block;font-size:11px;padding:4px 8px;border-radius:5px;background:#334332;margin:3px}.tag.actual{background:#d2ed9d;color:#26361f}details{margin-top:22px;color:#aebdaf;font-size:13px}summary{cursor:pointer}footer{margin-top:36px;border-top:1px solid #34433b;padding-top:18px;font-size:12px;color:#8b9f8e}.success{color:#d2ed9d}.hint{font-size:13px;min-height:24px}progress{width:100%;height:5px;accent-color:#c5e98b;margin-top:16px}@media(max-width:760px){main{padding:24px 18px}.layout{grid-template-columns:1fr;gap:30px}header{align-items:flex-start}.badge{font-size:10px}.grid{max-width:440px;margin:auto}.cell{min-height:55px}}
@media(prefers-reduced-motion:reduce){*{transition:none!important}}

/* A single-column, touch-first play surface, including on desktop. */
main{max-width:500px;padding:16px 14px 28px}header{padding-bottom:14px;gap:8px}h1{font-size:28px;margin:3px 0;letter-spacing:-1px}.eyebrow{font-size:9px;letter-spacing:2px}header p{font-size:12px}.badge{font-size:9px;padding:7px 10px}.layout{display:block;padding-top:0}.boardpanel{position:sticky;top:0;z-index:5;background:#101917;padding:12px 0 10px;border-bottom:1px solid #34433b;box-shadow:0 10px 16px #101917aa}.boardtop{margin-bottom:8px}.boardtop h2{font-size:14px}.count{font-size:13px}.grid{width:min(100%,228px);padding:10px;gap:7px;border-radius:14px;margin:auto}.cell{border-radius:9px;min-height:0}.cell:after{width:10px;height:10px}.coord{font-size:9px;left:5px;top:3px}.cell.selected{outline-offset:1px}.actions{margin-top:6px;gap:8px}.plain{min-height:44px;padding:8px 12px;font-size:12px}button{touch-action:manipulation;-webkit-tap-highlight-color:transparent}button:disabled{opacity:.4;cursor:default}progress{margin-top:8px;height:4px}.inspect{margin-top:5px;padding:8px 10px;min-height:44px;font-size:11px;line-height:1.5}.inspect p{margin:0;font-size:11px}.inspect strong{color:#e9f0df}.hint{margin:0;font-size:12px;min-height:0}.hint:empty{display:none}.rulespanel{padding-top:20px}.rulespanel h2{font-size:18px}.rules{gap:8px}.rule{padding:0;gap:0;overflow:hidden;min-height:78px}.rule.preview{border-color:#f3c589}.rule-info{display:flex;gap:10px;align-items:flex-start;flex:1;min-width:0;border:0;background:none;text-align:left;padding:13px 10px;color:inherit;min-height:76px}.rule-info strong{font-size:13px}.desc{font-size:11px;line-height:1.4}.num{padding-top:2px}.rule-toggle{align-self:stretch;display:flex;flex-direction:column;align-items:center;justify-content:center;gap:5px;min-width:68px;min-height:48px;border:0;border-left:1px solid #3b4b40;background:#ffffff04}.switch{margin:0;width:44px;height:25px}.on .switch:before{transform:translateX(19px)}.state{font-size:10px;margin:0}.tap-note{font-size:11px;color:#d3bd97;display:block;margin-top:3px}.clear{border:0;background:transparent;color:#f3c589;padding:4px 8px;min-height:44px;font-size:11px;float:right}.inspect{display:flow-root}.inspect .clear{margin:-8px -5px -8px 5px}details{font-size:12px}summary{min-height:44px;display:flex;align-items:center}footer{font-size:11px;margin-top:20px}.boardpanel:focus-within{z-index:6}@media(max-height:650px){.grid{width:184px;gap:5px;padding:8px}.boardpanel{padding-top:6px}.inspect{padding:5px 8px}.actions .plain{min-height:40px}.boardtop{margin-bottom:5px}}@media(max-height:430px) and (orientation:landscape){.boardpanel{position:relative}}
.rules{gap:6px}.rule{min-height:54px}.rule-info{min-height:54px;align-items:center;padding:10px}.rule-info .num{align-self:center;padding-top:0}.rule-toggle{min-height:54px}.rule-info strong{font-size:13px}.rule{flex-wrap:wrap}.rule-info{flex-basis:calc(100% - 68px)}.rule-explanation{flex-basis:100%;margin:0;padding:0 14px 12px 36px;font-size:12px;line-height:1.5;color:#b9c9b5}.rule-explanation[hidden]{display:none}.rule-explanation span{display:block;margin-top:6px;font-size:11px;color:#d3bd97}.rule-toggle{align-self:flex-start}.board-tools{display:flex;align-items:center;gap:8px;margin-top:5px}.board-tools .inspect{flex:1;min-width:0;margin:0}.board-tools #reset{flex-shrink:0}.rulespanel{padding-top:14px}.rule-toggle{min-width:76px;flex-direction:row;gap:0;justify-content:center}.rule-info{flex-basis:calc(100% - 76px)}.rule-toggle .switch{width:54px;height:30px;background:#465247}.rule-toggle .switch:before{width:22px;height:22px;left:4px;top:4px;background:#c4cdc0}.rule.on .rule-toggle .switch{background:#b7ce87}.rule.on .rule-toggle .switch:before{transform:translateX(24px);background:#24321e}.rule-toggle .state{position:absolute;right:5px;left:auto;top:0;line-height:30px;font-size:9px;font-weight:600;letter-spacing:.2px;color:#d4decb;margin:0}.rule.on .rule-toggle .state{left:5px;right:auto;color:#26361f}
@media(min-width:800px){
 main{max-width:1100px;padding:32px 36px 36px}
 header{padding-bottom:22px}h1{font-size:40px}header p{font-size:14px}.eyebrow{font-size:10px}.badge{font-size:11px}
 .layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1.08fr);align-items:start;gap:48px;padding-top:28px}
 .boardpanel{position:sticky;top:24px;padding:0 0 18px;border:0;box-shadow:none}
 .grid{width:100%;max-width:380px;padding:18px;gap:12px;border-radius:20px}
 .cell{border-radius:13px}.cell:after{width:14px;height:14px}.coord{font-size:11px;top:7px;left:9px}
 progress{margin-top:18px}.board-tools{margin-top:10px}.board-tools .inspect{font-size:12px;padding:12px;min-height:62px}.inspect p{font-size:12px}
 .rulespanel{padding-top:0}.rulespanel h2{font-size:22px}.rulespanel>p{margin-bottom:18px}.rules{gap:8px}
 .rule-info{min-height:58px;padding:12px}.rule-info strong{font-size:14px}.rule-toggle{min-height:58px}
 .rule-explanation{font-size:13px;padding-left:38px;padding-bottom:14px}.rule-explanation span{font-size:12px}
 details{margin-top:16px;font-size:13px}footer{margin-top:26px;padding-top:16px}
}
@media(min-width:800px) and (max-width:950px){main{padding:26px}.layout{gap:28px}}
@media(hover:hover){.rule-info:hover{background:#ffffff06}.rule-toggle:hover{background:#ffffff0b}}
.brand{margin:5px 0;width:min(280px,52vw);line-height:0;letter-spacing:normal}.brand img{display:block;width:100%;height:auto;aspect-ratio:5.8;object-fit:cover;object-position:center 48%}
.header-actions{display:flex;gap:8px;flex-shrink:0}header>div:first-child{min-width:0}.welcome-steps{padding-left:20px;color:#bdcbb6;font-size:14px;line-height:1.6}.welcome-steps li{margin-bottom:10px}.welcome-start{width:100%;background:#c5e98b;color:#1c2a18;border-color:#c5e98b;font-weight:600}#welcome-dialog h2{font-size:24px}@media(max-width:420px){header{flex-wrap:wrap}.header-actions{margin-left:auto}.header-actions .plain{padding:8px 10px}}
@media(min-width:800px){
 main{max-width:none;width:100%;padding:clamp(24px,3vw,64px)}
 .layout{grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:clamp(28px,4vw,88px);padding-top:clamp(24px,3vh,40px)}
 .boardpanel{top:24px;min-width:0}
 .grid{width:min(100%,max(280px,calc(100dvh - 280px)));max-width:none;margin-inline:auto;padding:clamp(14px,1.4vw,26px);gap:clamp(10px,1vw,20px)}
 .cell{border-radius:clamp(12px,1.3vw,22px)}.cell:after{width:clamp(14px,1.6vw,25px);height:clamp(14px,1.6vw,25px)}.coord{font-size:clamp(11px,.9vw,16px)}
 .brand{width:clamp(280px,23vw,440px)}
 .rulespanel h2{font-size:clamp(22px,1.8vw,30px)}
 .rules{gap:clamp(8px,1.1vh,14px)}
 .rule-info,.rule-toggle{min-height:clamp(58px,7.5vh,86px)}
 .rule-info{padding:clamp(12px,1.2vw,22px);gap:16px}.rule-info strong{font-size:clamp(14px,1.15vw,21px)}.num{font-size:clamp(12px,.9vw,16px)}
 .rule-explanation{font-size:clamp(13px,1vw,17px)}.rule-explanation span{font-size:clamp(12px,.9vw,15px)}
 .board-tools .inspect p,details{font-size:clamp(12px,1vw,16px)}
 header p,#puzzle-meta{font-size:clamp(13px,1vw,17px)}
}
dialog{color:#e9f0df;background:#19251f;border:1px solid #53664c;border-radius:18px;padding:26px;width:min(420px,calc(100% - 32px));max-height:85dvh;overflow:auto;box-shadow:0 20px 90px #0009}dialog::backdrop{background:#07110bc9}dialog h2{padding-right:26px;font-size:26px}dialog p{font-size:14px}.modal-close{position:absolute;right:10px;top:10px;width:44px;height:44px;border:0;background:none;font-size:25px}.stats{display:grid;grid-template-columns:repeat(3,1fr);gap:8px;margin:24px 0 8px}.stats div{padding:14px 5px;text-align:center;border:1px solid #43533b;border-radius:10px}.stats strong{display:block;font-size:25px;color:#d2ed9d}.stats span{font-size:11px;color:#aebdaf}.modal-actions{display:flex;gap:10px;flex-wrap:wrap}.archive-item{width:100%;display:flex;justify-content:space-between;gap:12px;text-align:left;padding:16px 12px;margin-top:10px;background:#263327;border:1px solid #506046;border-radius:9px;min-height:56px}.archive-item small{display:block;color:#aebdaf;margin-top:4px}.solved-mark{color:#d2ed9d;font-size:12px;align-self:center}.save-note{font-size:11px;margin:12px 0 0}.save-note:empty{display:none}#puzzle-meta{font-size:12px;color:#b8c5b1;margin-top:6px}.replay-note{color:#d2ed9d}
/* Printed coordinates and frosted, shallow raised light buttons. */
.grid{
 --axis:16px;--panel-gap:7px;
 grid-template-columns:var(--axis) repeat(4,minmax(0,1fr));
 grid-template-rows:var(--axis) repeat(4,minmax(0,1fr));
 gap:var(--panel-gap);padding:12px 14px 16px 10px;
 background:linear-gradient(145deg,#213c2b,#172e22 55%,#14291e);
 border:1px solid #48674c;border-radius:20px;
 box-shadow:inset 0 1px 1px #adc79a55,inset 0 -2px 2px #06150d99,0 5px 12px #0005;
}
.axis{align-self:center;justify-self:center;font-size:11px;line-height:1;font-weight:600;color:#c5cfb9;user-select:none;text-shadow:none}
.axis.active{color:#b8e9ff}
.cell,.cell.lit{
 min-width:0;min-height:0;aspect-ratio:1;border:1px solid #17291e;
 padding:0;border-radius:16%;isolation:isolate;overflow:visible;
 background:linear-gradient(160deg,#536b4e 0%,#2d4832 18%,#102419 72%,#0b1a12 100%);
 box-shadow:0 3px 3px #051009aa,inset 0 1px 1px #abc59b55;
 transition:box-shadow .18s,border-color .18s;
}
.cell::before{
 content:'';position:absolute;inset:2px 2px 4px;border-radius:15%;pointer-events:none;
 background:radial-gradient(ellipse at 46% 40%,#294632 0%,#203c2b 45%,#172e21 90%);
 box-shadow:inset 0 1px 1px #c3d9ac66,inset 0 -2px 5px #071b1480;
 transition:opacity .18s;
}
.cell::after,.cell.lit::after{
 content:'';display:block;position:absolute;inset:2px 2px 4px;width:auto;height:auto;margin:0;border:0;border-radius:15%;pointer-events:none;opacity:0;
 background:radial-gradient(ellipse at 47% 42%,#f2ffc2 0%,#e1f79f 28%,#d1ed8e 58%,#a9ca70 100%);
 box-shadow:inset 0 1px 1px #ffffe8,inset 0 -2px 6px #708a4666,0 0 11px #c5e98b15;
 transition:opacity .22s ease-in-out;
}
.cell.lit::after{opacity:1}
.grid.celebrating{animation:panel-solved .85s ease-in-out .2s both}
@keyframes panel-solved{
 0%,100%{filter:brightness(1)}
 45%{filter:brightness(1.24);box-shadow:inset 0 0 22px #d8f5aa40,0 0 36px #c5e98b55,0 5px 12px #0005}
}
.cell.selected,.cell.lit.selected,.cell.preview,.cell.lit.preview{
 border-color:#b8e9ff;outline:1px solid #b8e9ff;outline-offset:0;
 box-shadow:0 0 0 1px #071c16,0 3px 4px #020b08aa,inset 0 0 0 1px #b8e9ff;
}
.cell:focus-visible{outline:2px solid #e9f5ff;outline-offset:3px}
.rule.could{box-shadow:inset 3px 0 #b8e9ff}.rule.preview{border-color:#b8e9ff}.clear{color:#b8e9ff}
@media(min-width:800px){
 .grid{--axis:clamp(20px,2vw,34px);--panel-gap:clamp(10px,1vw,20px);padding:clamp(16px,1.5vw,28px);padding-left:clamp(10px,1vw,18px)}
 .axis{font-size:clamp(13px,1.2vw,20px)}
 .cell::before,.cell::after,.cell.lit::after{inset:3px 3px 5px}
}
@media(max-height:650px) and (max-width:799px){.grid{--axis:13px;--panel-gap:5px;padding:8px 10px 12px 6px}.axis{font-size:10px}}
@media(prefers-reduced-motion:reduce){.cell,.cell::before,.cell::after{transition:none}.grid.celebrating{animation:none}}