:root{color-scheme:dark;--ink:#eef1e9;--muted:#b7c3c7;--navy:#101b28;--panel:#142332;--line:#365061;--lime:#dbf477;--coral:#ff907b;--font:'Segoe UI',Arial,sans-serif;--display:'Trebuchet MS','Segoe UI',Arial,sans-serif}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;min-width:320px;background:var(--navy);color:var(--ink);font-family:var(--font);-webkit-font-smoothing:antialiased}
button,a{-webkit-tap-highlight-color:transparent}
button{font:inherit;cursor:pointer}
a{color:inherit}
::selection{background:var(--lime);color:var(--navy)}
:focus-visible{outline:3px solid var(--lime);outline-offset:4px}
.page-shell{max-width:1190px;margin:0 auto;padding:0 36px}
.site-header{height:96px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid #39515b}
.brand{display:inline-flex;gap:12px;align-items:center;text-decoration:none;font-family:var(--display);font-size:20px;font-weight:700;letter-spacing:-.03em}
.brand-dot{color:var(--lime)}
.brand-symbol{width:24px;height:24px;display:inline-grid;place-items:center;border:2px solid var(--lime);border-radius:50%;transform:rotate(-30deg)}
.brand-symbol span{display:block;width:29px;height:7px;border:2px solid var(--lime);border-radius:50%;transform:rotate(-22deg)}
.header-note{font-size:13px;color:var(--muted)}
.main-layout{display:grid;grid-template-columns:minmax(0,1fr) minmax(360px,520px);gap:68px;align-items:center;min-height:calc(100vh - 166px);padding:54px 0 64px}
.intro{position:relative;align-self:stretch;display:flex;flex-direction:column;justify-content:center;overflow:hidden}
h1{position:relative;z-index:1;margin:0;font-family:var(--display);font-size:clamp(62px,6.8vw,92px);line-height:.98;font-weight:700;letter-spacing:-.035em}
h1 em{font-style:normal;color:var(--lime)}
.intro>p{position:relative;z-index:1;max-width:420px;margin:28px 0 0;color:#d2dcda;font-size:17px;line-height:1.6}
.instruction{position:relative;z-index:1;display:flex;align-items:center;gap:14px;max-width:365px;margin-top:43px;padding-top:23px;border-top:1px solid var(--line);color:var(--muted);font-size:14px;line-height:1.45}
.instruction-mark{color:var(--lime);font-size:26px;line-height:1}
.orbit-art{position:absolute;right:-100px;bottom:-165px;width:340px;height:340px;opacity:.27;pointer-events:none}
.art-ring{position:absolute;left:50%;top:50%;border:1px solid #7c9a91;border-radius:50%;transform:translate(-50%,-50%) rotate(-28deg) scaleY(.62)}
.art-ring-one{width:330px;height:330px}.art-ring-two{width:220px;height:220px;transform:translate(-50%,-50%) rotate(35deg) scaleY(.8)}
.art-core{position:absolute;left:50%;top:50%;width:86px;height:86px;border-radius:50%;background:var(--lime);transform:translate(-50%,-50%)}
.game-section{min-width:0;border:1px solid #436071;background:var(--panel)}
.game-topline,.game-bottomline{display:flex;align-items:center;justify-content:space-between;gap:20px;padding:17px 22px}
.game-topline{border-bottom:1px solid var(--line)}
.game-name{display:flex;align-items:center;gap:9px;font-family:var(--display);font-size:14px;font-weight:700;letter-spacing:.12em}
.live-dot{width:7px;height:7px;background:var(--lime);border-radius:50%}
.scoreboard{display:flex;gap:26px;font-family:var(--display);font-size:11px;font-weight:600;letter-spacing:.08em;color:#b8c8ca}
.scoreboard span{white-space:nowrap}.scoreboard strong{margin-left:7px;color:var(--ink);font-size:19px;font-variant-numeric:tabular-nums;letter-spacing:0}
.board-wrap{position:relative;padding:20px;background:#0c1927}
.board{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;aspect-ratio:1/1;touch-action:none;user-select:none}
.cell{display:grid;place-items:center;min-width:0;border:1px solid #2c4453;background:#1d3141;color:transparent;font-family:var(--display);font-size:clamp(22px,3vw,39px);font-weight:700;font-variant-numeric:tabular-nums;letter-spacing:-.025em;transition:background .13s ease,color .13s ease,transform .13s ease}
.cell:not(.empty){color:#172636;animation:appear .13s ease-out}
.tile-2{background:#eaf5ce}.tile-4{background:#dbf477}.tile-8{background:#c9e776}.tile-16{background:#aed47b}.tile-32{background:#f8b091}.tile-64{background:#ff907b}.tile-128{background:#ffd17b}.tile-256{background:#f4c25d}.tile-512{background:#d7e68d}.tile-1024{background:#b8e7b9}.tile-2048{background:#e9ff9b}.tile-super{background:#f3dfaf}
.cell[data-digits="4"]{font-size:clamp(19px,2.6vw,31px)}.cell[data-digits="5"]{font-size:clamp(16px,2.3vw,27px)}
.game-overlay{position:absolute;inset:0;display:grid;place-items:center;padding:28px;background:#0a1725d9;text-align:center}
.game-overlay[hidden]{display:none}
.overlay-content{max-width:360px}.overlay-content h2{margin:0;font-family:var(--display);font-size:clamp(34px,4vw,48px);letter-spacing:-.03em}.overlay-content p{margin:14px 0 24px;color:#d0dedc;line-height:1.55}
.primary-button{display:inline-flex;align-items:center;justify-content:center;gap:24px;min-height:50px;padding:0 20px;border:0;background:var(--lime);color:#122130;font-family:var(--display);font-weight:700;transition:transform .18s ease,background .18s ease}
.primary-button:hover{transform:translateY(-2px);background:#ecffa1}.primary-button:active{transform:translateY(0)}
.game-bottomline{min-height:61px;border-top:1px solid var(--line);color:var(--muted);font-size:13px}.game-bottomline p{margin:0}.game-bottomline strong{color:var(--ink)}
.text-button{padding:4px 0;border:0;border-bottom:1px solid currentColor;background:transparent;color:var(--lime);font-size:13px;white-space:nowrap}.text-button:hover{color:#efffb1}
.footnote{display:flex;justify-content:space-between;gap:20px;padding:0 0 36px;color:#9fb3b7;font-size:12px}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}
@keyframes appear{from{transform:scale(.9)}to{transform:scale(1)}}
@media(max-width:960px){.main-layout{grid-template-columns:minmax(0,1fr) minmax(320px,460px);gap:30px}h1{font-size:clamp(55px,6vw,78px)}}
@media(max-width:760px){.page-shell{padding:0 18px}.site-header{height:70px}.header-note{display:none}.main-layout{display:block;min-height:0;padding:40px 0 28px}.intro{min-height:0;margin-bottom:38px}.intro>p{margin-top:18px;font-size:15px}.instruction{margin-top:25px;padding-top:18px}.orbit-art{right:-145px;bottom:-170px}.game-section{max-width:520px;margin:auto}.footnote{padding-bottom:28px}}
@media(max-width:430px){h1{font-size:57px}.game-topline,.game-bottomline{padding:14px}.board-wrap{padding:12px}.board{gap:7px}.scoreboard{gap:12px}.scoreboard strong{font-size:16px;margin-left:3px}.cell{font-size:26px}}
@media(prefers-reduced-motion:reduce){*,*::before,*::after{scroll-behavior:auto!important;transition-duration:.01ms!important;animation-duration:.01ms!important}}