:root {
  color-scheme: dark;
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--text);
  background: var(--page);
  --page: #181A20;
  --card: #222630;
  --stage: #1E232D;
  --stage-dot: #2E3442;
  --canvas-bg: #1B202A;
  --border: #343B4B;
  --field-border: #48556A;
  --field-frame: #2A3040;
  --overlay: #1B202AF0;
  --text: #E6E8EE;
  --muted: #9AA4B5;
  --accent: #4CC9F0;
  --accent-hover: #80DDF6;
  --accent-ink: #14242D;
  --hover: #2C3442;
  --selected: #293D4B;
  --selected-border: #497A91;
  --selected-text: #BDECF9;
  --icon-bg: #2D4351;
  --action-bg: #2B3241;
  --shadow: #0B0E1640;
  --tile-board: #343B4B;
  --tile-empty: #292F3B;
  --tile-text: #252833;
  --tile-2: #CDD9DF;
  --tile-4: #B7D7DD;
  --tile-8: #9ACBD0;
  --tile-16: #8BCDBB;
  --tile-32: #8AC4CF;
  --tile-64: #E9C989;
  --tile-128: #E5B981;
  --tile-256: #EAA686;
  --tile-512: #E88983;
  --tile-1024: #D6BBEB;
  --tile-2048: #F4C95D;
  --memory-back: #303D4F;
}
:root[data-theme="light"] {
  color-scheme: light;
  --page: #F2EFE9;
  --card: #F8F5EE;
  --stage: #E6E1D6;
  --stage-dot: #D3CFC7;
  --canvas-bg: #E8E3D9;
  --border: #D9D3C9;
  --field-border: #BFB8AC;
  --field-frame: #D8D2C8;
  --overlay: #F2EFE9F0;
  --text: #2B2D33;
  --muted: #626B78;
  --accent: #217E94;
  --accent-hover: #17697C;
  --accent-ink: #FFFFFF;
  --hover: #EBE5DB;
  --selected: #DCECEA;
  --selected-border: #91BFC2;
  --selected-text: #1E7080;
  --icon-bg: #DDEBEA;
  --action-bg: #EEE9DF;
  --shadow: #80746624;
  --tile-board: #D5D0C7;
  --tile-empty: #E9E4DA;
  --tile-text: #292D33;
  --tile-2: #C9DCE0;
  --tile-4: #AFD4D5;
  --tile-8: #8CC1C5;
  --tile-16: #84C4AD;
  --tile-32: #76ACB9;
  --tile-64: #D8B665;
  --tile-128: #D7A568;
  --tile-256: #D98E65;
  --tile-512: #D97971;
  --tile-1024: #B99ED0;
  --tile-2048: #C99E32;
  --memory-back: #DCE8E5;
}
* { box-sizing: border-box; }
body { min-width: 320px; margin: 0; }
button { font: inherit; cursor: pointer; }
button:focus-visible, a:focus-visible, summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
button:disabled { opacity: .38; cursor: default; }
[hidden] { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; }

.app-shell { max-width: 1220px; margin: 0 auto; padding: 0 32px 44px; }
.site-header { min-height: 86px; display: flex; align-items: center; justify-content: space-between; gap: 24px; border-bottom: 1px solid var(--border); transition: opacity .2s ease; }
.is-playing .site-header { opacity: .7; }
.is-playing .site-header:hover, .is-playing .site-header:focus-within { opacity: 1; }
.brand { display: inline-flex; align-items: center; flex: none; color: var(--text); text-decoration: none; }
.brand-mark { display: grid; place-items: center; width: 31px; height: 31px; margin-right: 10px; border-radius: 8px; background: var(--accent); color: var(--accent-ink); font-size: 21px; }
.brand-copy { display: flex; flex-direction: column; line-height: 1.1; }
.brand-copy strong { font-size: 19px; font-weight: 800; letter-spacing: -.6px; }
.brand-copy small { margin-top: 4px; color: var(--muted); font-size: 11px; font-weight: 500; letter-spacing: 0; }
.brand-dot { color: var(--accent); }
.game-nav { display: flex; align-items: center; gap: 5px; overflow-x: auto; scrollbar-width: none; }
.game-nav::-webkit-scrollbar { display: none; }
.theme-button { width: 36px; height: 36px; flex: none; display: grid; place-items: center; border: 1px solid var(--border); border-radius: 9px; background: var(--action-bg); color: var(--text); font-size: 20px; line-height: 1; }
.theme-button:hover { border-color: var(--selected-border); background: var(--hover); }
.nav-item { flex: none; border: 1px solid transparent; border-radius: 8px; background: transparent; color: var(--muted); padding: 9px 13px; font-size: 13px; font-weight: 650; }
.nav-item:hover { background: var(--hover); color: var(--text); }
.nav-item.active { border-color: var(--selected-border); background: var(--selected); color: var(--selected-text); }

.main-content { max-width: 1080px; margin: 34px auto 0; }
.play-layout { display: grid; grid-template-columns: minmax(0, 1fr) 250px; gap: 18px; align-items: start; }
.game-column { min-width: 0; }
.game-card { overflow: hidden; border: 1px solid var(--border); border-radius: 14px; background: var(--card); box-shadow: 0 22px 70px var(--shadow); }
.game-card-header { min-height: 87px; padding: 17px 27px; display: flex; align-items: center; justify-content: space-between; gap: 20px; border-bottom: 1px solid var(--border); }
.game-heading { display: flex; align-items: center; gap: 14px; min-width: 0; }
.game-heading h1 { font-size: 23px; line-height: 1.2; letter-spacing: -.8px; margin: 0; }
.game-symbol { width: 39px; height: 39px; flex: none; display: grid; place-items: center; border-radius: 9px; color: var(--selected-text); background: var(--icon-bg); font-size: 22px; font-weight: 700; }
.score-group { display: flex; gap: 27px; }
.score-item { min-width: 75px; display: flex; flex-direction: column; align-items: flex-end; gap: 3px; }
.score-item span { color: var(--muted); font-size: 11px; }
.score-item strong { color: var(--accent); font-size: 22px; font-weight: 800; letter-spacing: -.7px; font-variant-numeric: tabular-nums; }
.score-item.best strong { color: var(--text); }

.game-stage { position: relative; min-height: 530px; padding: 25px; display: flex; align-items: center; justify-content: center; background-color: var(--stage); background-image: radial-gradient(var(--stage-dot) 1px, transparent 1px); background-size: 20px 20px; }
.canvas-wrap { position: relative; height: min(60vh, 480px); min-height: 360px; aspect-ratio: 1 / 2; border: 1px solid var(--field-border); border-radius: 6px; overflow: hidden; box-shadow: 0 0 0 7px var(--field-frame), 0 16px 42px var(--shadow); }
canvas { width: 100%; height: 100%; display: block; background: var(--canvas-bg); }
.stage-overlay, .board-overlay { z-index: 2; display: flex; flex-direction: column; align-items: center; justify-content: center; text-align: center; background: var(--overlay); padding: 20px; }
.stage-overlay { position: absolute; inset: 0; }
.board-overlay { position: absolute; inset: 0; }
.stage-overlay h2, .board-overlay h2 { margin: 14px 0 5px; font-size: 21px; letter-spacing: -.5px; }
.stage-overlay p, .board-overlay p { margin: 0 0 23px; color: var(--muted); font-size: 12px; }
.stage-overlay h2:empty, .stage-overlay p:empty { display: none; }
.primary-button { min-width: 160px; display: inline-flex; align-items: center; justify-content: space-between; gap: 20px; border: 0; border-radius: 8px; background: var(--accent); color: var(--accent-ink); padding: 11px 15px; font-size: 12px; font-weight: 800; }
.primary-button:hover { background: var(--accent-hover); }
.game-card-footer { min-height: 64px; padding: 10px 22px; display: flex; justify-content: flex-end; align-items: center; border-top: 1px solid var(--border); }
.game-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.action-button { min-height: 36px; border: 1px solid var(--border); border-radius: 7px; background: var(--action-bg); color: var(--text); padding: 7px 11px; font-size: 15px; }
.action-button span { margin-left: 4px; font-size: 12px; }
.action-button:hover:not(:disabled) { border-color: var(--selected-border); color: var(--selected-text); }
.action-button[aria-pressed="true"] { border-color: var(--selected-border); color: var(--accent); }

.tile-board { width: min(100%, 420px); aspect-ratio: 1; display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; padding: 10px; border-radius: 11px; background: var(--tile-board); box-shadow: 0 0 0 7px var(--field-frame); touch-action: none; }
.tile { display: grid; place-items: center; border-radius: 6px; background: var(--tile-empty); color: var(--tile-text); font-size: clamp(20px, 3vw, 34px); font-weight: 800; letter-spacing: -1px; }
.tile[data-value="2"] { background: var(--tile-2); }
.tile[data-value="4"] { background: var(--tile-4); }
.tile[data-value="8"] { background: var(--tile-8); }
.tile[data-value="16"] { background: var(--tile-16); }
.tile[data-value="32"] { background: var(--tile-32); }
.tile[data-value="64"] { background: var(--tile-64); }
.tile[data-value="128"] { background: var(--tile-128); }
.tile[data-value="256"] { background: var(--tile-256); }
.tile[data-value="512"] { background: var(--tile-512); }
.tile[data-value="1024"] { background: var(--tile-1024); font-size: clamp(16px, 2.4vw, 26px); }
.tile[data-value="2048"] { background: var(--tile-2048); font-size: clamp(16px, 2.4vw, 26px); }
.memory-board { width: min(100%, 430px); display: grid; grid-template-columns: repeat(4, 1fr); gap: 11px; }
.memory-card { aspect-ratio: 1; border: 1px solid var(--field-border); border-radius: 9px; background: var(--memory-back); color: var(--accent); font-size: clamp(22px, 3.3vw, 39px); font-weight: 800; transition: transform .18s, background .18s; }
.memory-card:hover:not(:disabled) { transform: translateY(-3px); background: var(--hover); }
.memory-card.flipped { background: var(--tile-2); color: var(--tile-text); }
.memory-card.matched { background: var(--tile-4); color: var(--tile-text); border-color: var(--tile-4); }

.mobile-controls { display: none; }
.info-card { border: 1px solid var(--border); border-radius: 12px; background: var(--card); padding: 21px 20px; }
.info-card h2 { margin: 0; font-size: 16px; letter-spacing: -.3px; }
.info-card p { margin: 17px 0 21px; color: var(--muted); font-size: 12px; line-height: 1.65; }
.controls { display: grid; gap: 10px; padding-top: 18px; border-top: 1px solid var(--border); }
.control-row { display: flex; align-items: center; justify-content: space-between; gap: 20px; color: var(--muted); font-size: 12px; }
.key { min-height: 23px; display: inline-grid; place-items: center; border: 1px solid var(--field-border); border-bottom-width: 2px; border-radius: 4px; background: var(--action-bg); color: var(--text); padding: 2px 6px; font-size: 10px; white-space: nowrap; }

@media (max-width: 760px) {
  .app-shell { padding: 0 18px 32px; }
  .site-header { display: grid; grid-template-columns: 1fr auto; gap: 12px; min-height: 0; padding: 17px 0 12px; }
  .brand { grid-column: 1; }
  .theme-button { grid-column: 2; grid-row: 1; }
  .game-nav { grid-column: 1 / -1; grid-row: 2; margin: 0 -18px; padding: 0 18px; }
  .main-content { margin-top: 20px; }
  .play-layout { display: block; }
  .info-card { margin-top: 14px; }
  .game-stage { min-height: 470px; }
  .canvas-wrap { height: 410px; min-height: 0; }
  .mobile-controls { display: flex; justify-content: center; flex-wrap: wrap; gap: 8px; margin-top: 15px; }
  .mobile-controls:empty { display: none; }
  .mobile-controls button { min-width: 52px; min-height: 44px; border: 1px solid var(--field-border); border-radius: 8px; background: var(--action-bg); color: var(--text); font-size: 19px; }
  .mobile-controls button:active { background: var(--accent); color: var(--accent-ink); }
}
@media (max-width: 520px) {
  .game-card-header { padding: 15px 16px; gap: 10px; }
  .game-heading { gap: 9px; }
  .game-heading h1 { font-size: 18px; }
  .game-symbol { width: 32px; height: 32px; font-size: 18px; }
  .score-group { gap: 13px; }
  .score-item { min-width: 55px; }
  .score-item span { font-size: 9px; }
  .score-item strong { font-size: 17px; }
  .game-stage { min-height: 410px; padding: 17px; }
  .canvas-wrap { height: 370px; }
  .tile-board { gap: 6px; padding: 6px; }
  .memory-board { gap: 7px; }
  .game-card-footer { min-height: 56px; padding: 8px 12px; }
  .info-card { padding: 17px 18px; }
}
@media (max-width: 370px) {
  .app-shell { padding-left: 12px; padding-right: 12px; }
  .game-nav { margin: 0 -12px; padding: 0 12px; }
  .canvas-wrap { height: 330px; }
  .game-stage { min-height: 370px; padding: 13px; }
  .score-group { gap: 8px; }
  .score-item { min-width: 48px; }
}