:root{
  --bg:#000610;--panel:#010e1c;--panel2:#011828;--border:#0e2a40;
  --cyan:#00c8f0;--red:#ff2033;--green:#00ff9d;--amber:#f0a500;--violet:#8b5cf6;
  --text:#7ab8d4;--dim:#2a5a7a;--bright:#b8dcf0;--white:#e0f2ff;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%;background:var(--bg);color:var(--text);font-family:system-ui, -apple-system, "Segoe UI", Roboto, sans-serif,sans-serif;overflow:hidden;user-select:none;-webkit-user-select:none}
body::after{content:'';position:fixed;inset:0;pointer-events:none;background:repeating-linear-gradient(0deg,transparent,transparent 2px,rgba(0,16,30,.08) 2px,rgba(0,16,30,.08) 4px);z-index:1}

/* ─── Layout ─── */
.wrap{position:relative;z-index:2;height:100vh;display:grid;grid-template-columns:1fr 320px;gap:1rem;padding:1rem}
@media(max-width:900px){.wrap{grid-template-columns:1fr;grid-template-rows:1fr auto}}

.left{display:flex;flex-direction:column;gap:.8rem;min-width:0;align-items:center;justify-content:center}
.right{display:flex;flex-direction:column;gap:.6rem;overflow-y:auto;padding:.5rem 0}

/* ─── Header ─── */
.head{display:flex;align-items:center;justify-content:space-between;width:100%;max-width:520px;padding:.4rem .2rem}
.title{font-family:"Impact", "Arial Black", system-ui, sans-serif,sans-serif;font-size:1.4rem;letter-spacing:.12em;color:var(--white);filter:drop-shadow(0 0 8px var(--cyan))}
.title em{color:var(--cyan);font-style:normal}
.scores{display:flex;gap:.5rem}
.sc{background:color-mix(in srgb,var(--cyan) 6%,transparent);border:1px solid var(--border);border-left:3px solid var(--cyan);padding:.3rem .6rem;min-width:78px;text-align:center}
.sc.b{border-left-color:var(--amber)}
.sc label{display:block;font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.5rem;letter-spacing:.15em;color:var(--dim)}
.sc .v{font-family:"Impact", "Arial Black", system-ui, sans-serif,sans-serif;font-size:1rem;color:var(--white);line-height:1.2}
.sc.b .v{color:var(--amber)}

/* ─── Grille ─── */
.boardWrap{position:relative;width:min(520px,calc(100vw - 360px),calc(100vh - 220px));aspect-ratio:1;background:var(--panel);border:1px solid var(--border);padding:8px}
@media(max-width:900px){.boardWrap{width:min(420px,calc(100vw - 2rem),calc(100vh - 280px))}}
.board{position:relative;width:100%;height:100%;display:grid;grid-template-columns:repeat(4,1fr);grid-template-rows:repeat(4,1fr);gap:8px}
.cell{background:color-mix(in srgb,var(--cyan) 4%,transparent);border:1px solid var(--border);position:relative}
.tile{position:absolute;display:flex;align-items:center;justify-content:center;font-family:"Impact", "Arial Black", system-ui, sans-serif,sans-serif;font-weight:600;
  border:1px solid var(--border);transition:transform .12s ease,opacity .12s ease;pointer-events:none;will-change:transform}
.tile.t-new{animation:pop .18s ease}
.tile.t-merge{animation:merge .18s ease}
@keyframes pop{from{transform:scale(.4);opacity:0}to{transform:scale(1);opacity:1}}
@keyframes merge{0%{transform:scale(1)}50%{transform:scale(1.18)}100%{transform:scale(1)}}

/* Couleurs des tuiles — palette néon cohérente */
.v-2    {background:#0a1a2a;color:#5a8090;border-color:#1a2a3a}
.v-4    {background:#0d2438;color:#8ab4cc;border-color:#1c3a52}
.v-8    {background:rgba(0,200,240,.18);color:#00c8f0;border-color:#00c8f0;box-shadow:0 0 8px rgba(0,200,240,.3)}
.v-16   {background:rgba(0,255,157,.15);color:#00ff9d;border-color:#00ff9d;box-shadow:0 0 8px rgba(0,255,157,.3)}
.v-32   {background:rgba(240,165,0,.18);color:#f0a500;border-color:#f0a500;box-shadow:0 0 10px rgba(240,165,0,.3)}
.v-64   {background:rgba(255,140,40,.22);color:#ff8c28;border-color:#ff8c28;box-shadow:0 0 12px rgba(255,140,40,.4)}
.v-128  {background:rgba(255,32,51,.18);color:#ff2033;border-color:#ff2033;box-shadow:0 0 14px rgba(255,32,51,.4)}
.v-256  {background:rgba(255,32,140,.2);color:#ff2090;border-color:#ff2090;box-shadow:0 0 16px rgba(255,32,140,.45)}
.v-512  {background:rgba(139,92,246,.2);color:#a78bfa;border-color:#8b5cf6;box-shadow:0 0 18px rgba(139,92,246,.5)}
.v-1024 {background:rgba(240,200,0,.22);color:#ffd700;border-color:#ffd700;box-shadow:0 0 22px rgba(255,215,0,.55)}
.v-2048 {background:rgba(255,215,0,.28);color:#fff;border-color:#fff;box-shadow:0 0 28px rgba(255,215,0,.7),inset 0 0 16px rgba(255,215,0,.4);animation:halo 2s ease-in-out infinite}
.v-4096,.v-8192,.v-big {background:linear-gradient(135deg,#00c8f0,#ff2090,#ffd700);color:#000;border-color:#fff;box-shadow:0 0 32px rgba(255,255,255,.6);animation:halo 1.5s ease-in-out infinite}
@keyframes halo{0%,100%{filter:brightness(1)}50%{filter:brightness(1.3)}}

/* Tailles de police pour gros chiffres */
.v-128,.v-256,.v-512{font-size:1.6rem}
.v-1024,.v-2048{font-size:1.3rem}
.v-4096,.v-8192,.v-big{font-size:1.1rem}

/* ─── Overlay ─── */
.over{position:absolute;inset:8px;background:rgba(0,6,16,.92);backdrop-filter:blur(6px);
  display:none;align-items:center;justify-content:center;flex-direction:column;gap:.8rem;text-align:center;padding:1rem;z-index:5}
.over.show{display:flex}
.over h2{font-family:"Impact", "Arial Black", system-ui, sans-serif,sans-serif;font-size:1.6rem;color:var(--cyan);filter:drop-shadow(0 0 12px var(--cyan));letter-spacing:.08em}
.over.win h2{color:var(--amber);filter:drop-shadow(0 0 12px var(--amber))}
.over .sub{font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.7rem;color:var(--text);letter-spacing:.1em;max-width:280px;line-height:1.6}
.over .btns{display:flex;gap:.6rem;flex-wrap:wrap;justify-content:center;margin-top:.5rem}

/* ─── Boutons ─── */
.btn{font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.62rem;letter-spacing:.14em;
  padding:.45rem 1rem;border:1px solid var(--cyan);color:var(--cyan);background:transparent;cursor:pointer;
  transition:all .15s;position:relative;
  clip-path:polygon(8px 0,100% 0,100% calc(100% - 8px),calc(100% - 8px) 100%,0 100%,0 8px)}
.btn:hover{background:color-mix(in srgb,var(--cyan) 12%,transparent);color:var(--white)}
.btn.amber{border-color:var(--amber);color:var(--amber)}
.btn.amber:hover{background:color-mix(in srgb,var(--amber) 12%,transparent);color:var(--white)}
.btn.red{border-color:var(--red);color:var(--red)}
.btn.red:hover{background:color-mix(in srgb,var(--red) 12%,transparent);color:var(--white)}
.btn:disabled{opacity:.4;cursor:not-allowed}

/* ─── Panneau IA ─── */
.panel{background:var(--panel);border:1px solid var(--border);border-left:3px solid var(--violet);padding:.7rem .9rem}
.panel h3{font-family:"Impact", "Arial Black", system-ui, sans-serif,sans-serif;font-size:.78rem;color:var(--violet);letter-spacing:.1em;margin-bottom:.5rem;display:flex;align-items:center;gap:.4rem}
.panel h3::before{content:'◆';color:var(--violet)}
.panel .row{display:flex;justify-content:space-between;align-items:center;font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.6rem;letter-spacing:.06em;padding:.18rem 0;color:var(--text)}
.panel .row b{color:var(--white);font-weight:400}
.panel .row b.c{color:var(--cyan)}
.panel .row b.g{color:var(--green)}
.panel .row b.a{color:var(--amber)}
.panel .row b.v{color:var(--violet)}
.panel .row b.r{color:var(--red)}

.slider{width:100%;margin:.4rem 0}
.slider label{display:flex;justify-content:space-between;font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.55rem;letter-spacing:.1em;color:var(--text);margin-bottom:.2rem}
.slider label b{color:var(--cyan)}
.slider input[type=range]{width:100%;-webkit-appearance:none;background:transparent;height:18px}
.slider input[type=range]::-webkit-slider-runnable-track{height:3px;background:var(--border);border-radius:0}
.slider input[type=range]::-webkit-slider-thumb{-webkit-appearance:none;width:12px;height:12px;background:var(--cyan);margin-top:-5px;border-radius:0;cursor:pointer;box-shadow:0 0 6px var(--cyan)}
.slider input[type=range]::-moz-range-track{height:3px;background:var(--border)}
.slider input[type=range]::-moz-range-thumb{width:12px;height:12px;background:var(--cyan);border:none;cursor:pointer;border-radius:0}

.dirHint{display:grid;grid-template-columns:repeat(3,1fr);gap:2px;width:90px;margin:.4rem auto 0}
.dirHint .d{width:28px;height:28px;border:1px solid var(--border);display:flex;align-items:center;justify-content:center;
  font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.7rem;color:var(--dim);background:transparent;transition:all .15s}
.dirHint .d.active{background:color-mix(in srgb,var(--violet) 22%,transparent);border-color:var(--violet);color:var(--violet);box-shadow:0 0 8px var(--violet)}
.dirHint .empty{visibility:hidden}

.brain{position:relative;height:60px;background:var(--panel2);border:1px solid var(--border);margin-top:.4rem;overflow:hidden}
.brain canvas{width:100%;height:100%;display:block}

.log{font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.52rem;color:var(--dim);background:var(--panel2);border:1px solid var(--border);padding:.4rem .55rem;max-height:90px;overflow-y:auto;line-height:1.7}
.log .l{display:block}
.log .l.move{color:var(--cyan)}
.log .l.merge{color:var(--green)}
.log .l.warn{color:var(--amber)}

.foot{font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.5rem;color:var(--dim);text-align:center;letter-spacing:.15em;padding:.3rem}
.foot a{color:var(--cyan);text-decoration:none}
.foot a:hover{color:var(--white)}

.kbd{display:inline-block;padding:1px 5px;background:var(--panel2);border:1px solid var(--border);border-radius:2px;font-family:ui-monospace, "SF Mono", Menlo, Consolas, monospace,monospace;font-size:.55rem;color:var(--text);margin:0 1px}

/* Retour menu — bouton flottant top-left */
.back-to-menu{position:fixed;top:.7rem;left:.7rem;z-index:9999;background:rgba(4,7,15,.85);color:#5dd4f7;border:1px solid rgba(93,212,247,.35);padding:.5rem .85rem;border-radius:8px;font-size:.78rem;font-family:system-ui,-apple-system,"Segoe UI",sans-serif;text-decoration:none;letter-spacing:.02em;backdrop-filter:blur(6px);transition:background .15s,border-color .15s,transform .12s}
.back-to-menu:hover,.back-to-menu:focus-visible{background:rgba(93,212,247,.2);border-color:#5dd4f7;outline:none}
.back-to-menu:active{transform:translateY(1px)}
@media (max-width:600px){
  .back-to-menu{font-size:.7rem;padding:.4rem .65rem;top:.4rem;left:.4rem}
}