:root {
  --gold:       #c9a84c;
  --gold-light: #e8c97a;
  --gold-dark:  #8a6a2a;
  --gold-glow:  rgba(201,168,76,.4);
  --bg:         #0e0b05;
  --panel-bg:   linear-gradient(160deg,#3a2a0c,#1e1408);
  --panel-b:    #7a5a1a;
  --ok:         #60d870;
  --err:        #e06060;
  --hint:       #60b8e8;
  --tab-active: rgba(201,168,76,.15);
}
*{box-sizing:border-box;margin:0;padding:0;}
body{
  background:var(--bg);
  background-image:radial-gradient(ellipse at 15% 15%,#241806 0%,transparent 55%),
                   radial-gradient(ellipse at 85% 85%,#160e03 0%,transparent 55%);
  min-height:100vh; display:flex; flex-direction:column; align-items:center;
  padding:16px 10px 60px; font-family:'Rajdhani',sans-serif; color:var(--gold-light);
  user-select:none;
}
h1{
  font-family:'Orbitron',monospace; font-weight:900;
  font-size:clamp(1.5rem,4vw,2.3rem); letter-spacing:.2em; color:var(--gold-light);
  text-shadow:0 0 30px var(--gold-glow),0 0 70px rgba(201,168,76,.15);
  text-transform:uppercase; margin-bottom:2px;
}
.subtitle{
  font-family:'Cinzel',serif; font-size:.72rem; color:var(--gold-dark);
  letter-spacing:.3em; text-transform:uppercase; margin-bottom:16px;
}

/* ── TABS ── */
.tabs-nav{
  display:flex; gap:4px; margin-bottom:18px;
  background:rgba(0,0,0,.35); border:1px solid var(--panel-b); border-radius:12px; padding:5px;
  flex-wrap:wrap; justify-content:center;
}
.tab-btn{
  font-family:'Orbitron',monospace; font-size:.62rem; font-weight:700;
  letter-spacing:.08em; padding:9px 18px; border-radius:8px;
  border:1px solid transparent; cursor:pointer; text-transform:uppercase;
  background:transparent; color:var(--gold-dark); transition:all .25s;
}
.tab-btn:hover{background:rgba(201,168,76,.07); color:var(--gold-light);}
.tab-btn.active{
  background:var(--tab-active); color:var(--gold-light);
  border-color:var(--gold-dark); box-shadow:0 0 16px rgba(201,168,76,.15);
}
.tab-pane{display:none; width:100%; max-width:1160px; animation:fadeIn .3s ease;}
.tab-pane.active{display:block;}
@keyframes fadeIn{from{opacity:0;transform:translateY(6px);}to{opacity:1;transform:none;}}

/* ── GAME TAB ── */
.main-layout{display:flex;gap:14px;align-items:flex-start;width:100%;}
.game-col{
  flex:1 1 auto; min-width:0;
  background:var(--panel-bg); border:2px solid var(--panel-b); border-radius:18px;
  padding:16px 14px 18px;
  box-shadow:0 0 50px rgba(201,168,76,.1),inset 0 0 40px rgba(0,0,0,.5);
}
.side-col{flex:0 0 290px;display:flex;flex-direction:column;gap:12px;}
.side-panel{
  background:var(--panel-bg); border:2px solid var(--panel-b); border-radius:18px;
  padding:14px 13px;
  box-shadow:0 0 40px rgba(201,168,76,.07),inset 0 0 30px rgba(0,0,0,.4);
}
.panel-title{
  font-family:'Orbitron',monospace;font-size:.7rem;font-weight:700;
  letter-spacing:.13em;color:var(--gold-light);margin-bottom:10px;
  text-align:center;text-transform:uppercase;
}
.options{
  display:flex;align-items:center;gap:12px;justify-content:center;margin-bottom:12px;
  font-size:.73rem;color:var(--gold-dark);font-weight:600;letter-spacing:.07em;flex-wrap:wrap;
}
.options label{display:flex;align-items:center;gap:5px;cursor:pointer;}
select{
  background:#1a1005;color:var(--gold-light);border:1px solid var(--gold-dark);
  border-radius:5px;padding:2px 8px;font-family:'Rajdhani',sans-serif;font-size:.82rem;
}
.stats-bar{display:flex;justify-content:center;gap:24px;margin-bottom:12px;flex-wrap:wrap;}
.stat-item{display:flex;flex-direction:column;align-items:center;}
.stat-val{font-family:'Orbitron',monospace;font-size:1.1rem;font-weight:700;color:var(--gold-light);line-height:1;}
.stat-lbl{font-size:.56rem;color:var(--gold-dark);letter-spacing:.12em;text-transform:uppercase;margin-top:2px;}
.message{text-align:center;font-family:'Orbitron',monospace;font-size:.68rem;min-height:22px;margin-bottom:10px;letter-spacing:.07em;color:var(--gold-light);transition:color .3s;}
.message.win{color:var(--ok);text-shadow:0 0 14px rgba(80,220,80,.5);}
.message.err{color:var(--err);}
.message.info{color:var(--hint);}
.turn-indicator{display:flex;justify-content:center;gap:24px;margin-bottom:10px;}
.turn-card{padding:6px 16px;border-radius:8px;text-align:center;border:1px solid rgba(138,106,42,.25);background:rgba(0,0,0,.3);transition:all .3s;}
.turn-card.active-turn{border-color:var(--gold);background:rgba(201,168,76,.12);box-shadow:0 0 14px var(--gold-glow);}
.turn-card.active-turn.enemy{border-color:var(--hint);background:rgba(96,184,232,.1);box-shadow:0 0 14px rgba(96,184,232,.3);}
.turn-name{font-family:'Orbitron',monospace;font-size:.6rem;letter-spacing:.1em;color:var(--gold-dark);text-transform:uppercase;}
.turn-name.mine{color:var(--gold);}
.turn-name.ai{color:var(--hint);}
.turn-score{font-family:'Orbitron',monospace;font-size:1.2rem;font-weight:900;color:var(--gold-light);}
.nim-board{background:rgba(0,0,0,.28);border:1px solid rgba(138,106,42,.22);border-radius:12px;padding:14px 12px;margin-bottom:12px;display:flex;flex-direction:column;gap:10px;}
.row-container{display:flex;align-items:center;gap:10px;}
.row-label{font-family:'Orbitron',monospace;font-size:.62rem;color:var(--gold-dark);width:20px;text-align:right;flex-shrink:0;}
.row-stones{display:flex;gap:5px;flex-wrap:wrap;flex:1;}
.stone{width:34px;height:34px;border-radius:50%;background:radial-gradient(circle at 35% 35%,#e8c97a,#8a6a2a 60%,#4a3a10);border:2px solid var(--gold-dark);cursor:pointer;transition:all .18s;box-shadow:0 2px 8px rgba(0,0,0,.5),inset 0 1px 3px rgba(255,255,255,.15);}
.stone:hover{transform:scale(1.12);box-shadow:0 0 14px var(--gold-glow),0 2px 8px rgba(0,0,0,.5);border-color:var(--gold-light);}
.stone.selected{background:radial-gradient(circle at 35% 35%,#ffffff,#e8c97a 50%,#c9a84c);border-color:var(--gold-light);box-shadow:0 0 18px rgba(255,255,220,.6),0 2px 8px rgba(0,0,0,.5);transform:scale(1.1);}
.stone.removed{background:rgba(0,0,0,.2);border:2px dashed rgba(138,106,42,.2);cursor:default;box-shadow:none;transform:none;}
.stone.removed:hover{transform:none;box-shadow:none;border-color:rgba(138,106,42,.2);}
.row-count{font-family:'Orbitron',monospace;font-size:.65rem;color:var(--gold-dark);width:22px;text-align:left;flex-shrink:0;}
.controls{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;}
button{font-family:'Orbitron',monospace;font-size:.58rem;font-weight:700;letter-spacing:.08em;padding:8px 14px;border-radius:7px;border:none;cursor:pointer;text-transform:uppercase;transition:all .2s;}
#btn-take{background:linear-gradient(135deg,var(--gold),var(--gold-dark));color:#1a1005;box-shadow:0 3px 12px rgba(201,168,76,.3);}
#btn-take:hover:not(:disabled){box-shadow:0 3px 22px rgba(201,168,76,.55);transform:translateY(-1px);}
#btn-take:disabled{opacity:.3;cursor:not-allowed;}
#btn-new{background:rgba(255,255,255,.06);color:var(--gold-dark);border:1px solid var(--gold-dark);}
#btn-new:hover{background:rgba(255,255,255,.13);color:var(--gold-light);}
.nim-value-display{background:rgba(0,0,0,.4);border:1px solid rgba(96,184,232,.25);border-radius:8px;padding:9px 11px;margin-bottom:8px;}
.nim-value-row{display:flex;justify-content:space-between;align-items:center;margin-bottom:5px;font-size:.69rem;}
.nim-value-row:last-child{margin-bottom:0;}
.nv-lbl{color:var(--gold-dark);letter-spacing:.05em;}
.nv-val{font-family:'Orbitron',monospace;font-weight:700;color:var(--gold-light);}
.nv-val.zero{color:var(--err);}
.nv-val.nonzero{color:var(--ok);}
.nv-val.xor{color:var(--hint);}
.nim-formula{background:rgba(0,0,0,.4);border:1px solid rgba(138,106,42,.3);border-radius:8px;padding:8px 10px;text-align:center;font-family:'Orbitron',monospace;font-size:.72rem;color:var(--gold-light);letter-spacing:.05em;}
.ai-hint{background:rgba(96,184,232,.07);border:1px solid rgba(96,184,232,.22);border-radius:8px;padding:8px 10px;margin-top:8px;font-size:.7rem;color:rgba(160,216,240,.9);line-height:1.6;}
.ai-hint em{color:var(--hint);font-style:normal;}
.theory-block{margin-bottom:11px;padding-bottom:11px;border-bottom:1px solid rgba(138,106,42,.18);}
.theory-block:last-child{margin-bottom:0;padding-bottom:0;border-bottom:none;}
.theory-title{font-family:'Orbitron',monospace;font-size:.56rem;color:var(--gold);letter-spacing:.1em;margin-bottom:6px;text-transform:uppercase;}
.theory-text{font-size:.72rem;color:rgba(200,180,120,.85);line-height:1.65;}
.theory-text em{color:var(--gold-light);font-style:normal;}
.example-box{background:rgba(0,0,0,.35);border:1px solid rgba(138,106,42,.22);border-radius:7px;padding:7px 9px;margin-top:6px;font-size:.67rem;color:rgba(200,180,120,.75);line-height:1.75;font-family:'Orbitron',monospace;}
.example-box .ex-title{color:var(--gold-dark);font-size:.5rem;margin-bottom:3px;letter-spacing:.1em;text-transform:uppercase;font-family:'Rajdhani',sans-serif;}
.history-list{max-height:150px;overflow-y:auto;font-size:.68rem;display:flex;flex-direction:column;gap:3px;}
.history-list::-webkit-scrollbar{width:4px;}
.history-list::-webkit-scrollbar-thumb{background:var(--gold-dark);border-radius:2px;}
.hist-item{display:flex;align-items:center;gap:6px;padding:3px 6px;border-radius:5px;border:1px solid rgba(138,106,42,.15);background:rgba(0,0,0,.2);}
.hist-who{font-family:'Orbitron',monospace;font-size:.52rem;width:22px;text-align:center;border-radius:3px;padding:1px 3px;}
.hist-who.p{background:rgba(201,168,76,.18);color:var(--gold);}
.hist-who.p2{background:rgba(180,96,220,.18);color:#d080f0;}
.hist-who.c{background:rgba(96,184,232,.12);color:var(--hint);}
/* Hint stone colors */
.stone.hint-win{
  background:radial-gradient(circle at 35% 35%,#c0ffb0,#40a830 60%,#1a6010);
  border-color:#60d870;box-shadow:0 0 10px rgba(96,216,112,.5),0 2px 8px rgba(0,0,0,.5);
}
.stone.hint-lose{
  background:radial-gradient(circle at 35% 35%,#ffc0c0,#c03030 60%,#6a1010);
  border-color:#e06060;box-shadow:0 0 10px rgba(224,96,96,.5),0 2px 8px rgba(0,0,0,.5);
}
.stone.hint-win:hover{box-shadow:0 0 18px rgba(96,216,112,.7),0 2px 8px rgba(0,0,0,.5);}
.stone.hint-lose:hover{box-shadow:0 0 18px rgba(224,96,96,.7),0 2px 8px rgba(0,0,0,.5);}
/* Hint toggle button */
#btn-hint{background:rgba(96,184,232,.1);color:var(--hint);border:1px solid rgba(96,184,232,.35);}
#btn-hint:hover{background:rgba(96,184,232,.2);color:#a0d8f0;}
#btn-hint.active{background:rgba(96,184,232,.2);border-color:var(--hint);box-shadow:0 0 10px rgba(96,184,232,.25);}
/* Hint legend */
.hint-legend{display:flex;gap:14px;justify-content:center;margin-top:7px;font-size:.62rem;color:var(--gold-dark);font-family:'Rajdhani',sans-serif;font-weight:600;letter-spacing:.06em;}
.hint-legend span{display:flex;align-items:center;gap:5px;}
.hint-dot{width:11px;height:11px;border-radius:50%;flex-shrink:0;}
.hint-dot.win{background:#40a830;border:1.5px solid #60d870;}
.hint-dot.lose{background:#c03030;border:1.5px solid #e06060;}
/* Losing-position warning */
.losing-warn{background:rgba(224,96,96,.08);border:1px solid rgba(224,96,96,.25);border-radius:8px;padding:8px 10px;margin-top:8px;font-size:.69rem;color:rgba(240,160,160,.9);line-height:1.6;text-align:center;font-family:'Orbitron',monospace;letter-spacing:.05em;}
/* P2 turn card */
.turn-name.p2{color:#d080f0;}
.turn-card.active-turn.p2-active{border-color:#d080f0;background:rgba(180,96,220,.1);box-shadow:0 0 14px rgba(180,96,220,.3);}
.hist-txt{color:rgba(200,180,120,.8);}
.win-overlay{position:fixed;inset:0;background:rgba(0,0,0,.85);display:flex;align-items:center;justify-content:center;z-index:100;opacity:0;pointer-events:none;transition:opacity .5s;}
.win-overlay.show{opacity:1;pointer-events:all;}
.win-box{background:linear-gradient(160deg,#3d2c0e,#251a06);border:2px solid var(--gold);border-radius:20px;padding:30px 44px;text-align:center;max-width:360px;box-shadow:0 0 70px var(--gold-glow),0 0 140px rgba(201,168,76,.12);}
.win-trophy{font-size:3.2rem;display:block;margin-bottom:10px;animation:pulse 1.2s ease-in-out infinite;}
@keyframes pulse{0%,100%{transform:scale(1);}50%{transform:scale(1.12);}}
.win-title{font-family:'Orbitron',monospace;font-weight:900;font-size:1.4rem;color:var(--gold-light);text-shadow:0 0 20px var(--gold-glow);margin-bottom:6px;}
.win-sub{font-size:.82rem;color:var(--gold-dark);margin-bottom:18px;line-height:2;}
.win-sub strong{color:var(--gold-light);}
.win-btn{font-family:'Orbitron',monospace;font-size:.68rem;font-weight:700;padding:11px 26px;border-radius:10px;border:none;background:linear-gradient(135deg,var(--gold),var(--gold-dark));color:#1a1005;cursor:pointer;letter-spacing:.1em;box-shadow:0 4px 18px rgba(201,168,76,.35);transition:all .2s;}
.win-btn:hover{transform:translateY(-2px);box-shadow:0 6px 28px rgba(201,168,76,.5);}
.particle{position:fixed;pointer-events:none;z-index:99;border-radius:50%;animation:pfall 1.9s ease-in forwards;}
@keyframes pfall{0%{transform:translateY(-30px) rotate(0deg);opacity:1;}100%{transform:translateY(105vh) rotate(720deg);opacity:0;}}

/* ── CONTENT TABS (Cómo Jugar / Estrategias / Teoría) ── */
.content-tab{
  background:var(--panel-bg); border:2px solid var(--panel-b); border-radius:18px;
  padding:28px 32px;
  box-shadow:0 0 50px rgba(201,168,76,.08),inset 0 0 40px rgba(0,0,0,.4);
}
.ct-h1{font-family:'Orbitron',monospace;font-size:1.1rem;font-weight:900;color:var(--gold-light);letter-spacing:.15em;text-transform:uppercase;margin-bottom:6px;}
.ct-sub{font-family:'Cinzel',serif;font-size:.68rem;color:var(--gold-dark);letter-spacing:.25em;text-transform:uppercase;margin-bottom:26px;padding-bottom:14px;border-bottom:1px solid rgba(138,106,42,.3);}
.ct-section{margin-bottom:32px;}
.ct-section-title{font-family:'Orbitron',monospace;font-size:.72rem;font-weight:700;color:var(--gold);letter-spacing:.12em;text-transform:uppercase;margin-bottom:12px;display:flex;align-items:center;gap:8px;}
.ct-section-title::before{content:'';display:inline-block;width:3px;height:14px;background:var(--gold);border-radius:2px;}
.ct-text{font-size:.85rem;color:rgba(210,190,130,.88);line-height:1.8;margin-bottom:10px;user-select:text;}
.ct-text em{color:var(--gold-light);font-style:normal;font-weight:600;}
.ct-text strong{color:var(--gold);font-weight:700;}
.ct-box{background:rgba(0,0,0,.4);border:1px solid rgba(138,106,42,.28);border-radius:10px;padding:14px 16px;margin:10px 0 14px;}
.ct-box-title{font-family:'Orbitron',monospace;font-size:.55rem;color:var(--gold-dark);letter-spacing:.15em;text-transform:uppercase;margin-bottom:8px;}
.ct-cols{display:grid;grid-template-columns:1fr 1fr;gap:14px;margin:14px 0;}
.ct-card{background:rgba(0,0,0,.35);border:1px solid rgba(138,106,42,.22);border-radius:10px;padding:13px 14px;}
.ct-card-title{font-family:'Orbitron',monospace;font-size:.58rem;color:var(--hint);letter-spacing:.1em;margin-bottom:8px;text-transform:uppercase;}
.ct-card p{font-size:.78rem;color:rgba(200,180,120,.82);line-height:1.7;user-select:text;}
.ct-badge{display:inline-block;padding:2px 8px;border-radius:4px;font-family:'Orbitron',monospace;font-size:.52rem;font-weight:700;letter-spacing:.06em;margin:2px;}
.badge-win{background:rgba(96,216,112,.18);color:var(--ok);border:1px solid rgba(96,216,112,.3);}
.badge-lose{background:rgba(224,96,96,.15);color:var(--err);border:1px solid rgba(224,96,96,.25);}
.badge-neutral{background:rgba(201,168,76,.15);color:var(--gold);border:1px solid rgba(201,168,76,.3);}
/* KaTeX overrides */
.katex{color:var(--gold-light)!important;font-size:0.95em;}
.katex-display{margin:12px 0!important;overflow-x:auto;}
/* math inline */
.math{color:var(--gold-light);}
/* Example game boards */
.eg-board{display:flex;flex-direction:column;gap:6px;background:rgba(0,0,0,.3);border:1px solid rgba(138,106,42,.2);border-radius:8px;padding:10px 12px;margin:8px 0;}
.eg-row{display:flex;align-items:center;gap:6px;}
.eg-lbl{font-family:'Orbitron',monospace;font-size:.55rem;color:var(--gold-dark);width:16px;}
.eg-stone{width:20px;height:20px;border-radius:50%;background:radial-gradient(circle at 35% 35%,#e8c97a,#8a6a2a 60%,#4a3a10);border:1.5px solid var(--gold-dark);display:inline-block;flex-shrink:0;}
.eg-stone.rem{background:rgba(0,0,0,.15);border:1.5px dashed rgba(138,106,42,.2);}
.eg-stone.hi{background:radial-gradient(circle at 35% 35%,#fff,#e8c97a 50%,var(--gold));border-color:var(--gold-light);box-shadow:0 0 8px var(--gold-glow);}
.eg-count{font-family:'Orbitron',monospace;font-size:.6rem;color:var(--gold-dark);margin-left:4px;}
/* XOR table */
.xor-table{width:100%;border-collapse:collapse;font-family:'Orbitron',monospace;font-size:.68rem;margin:8px 0;}
.xor-table th,.xor-table td{border:1px solid rgba(138,106,42,.25);padding:5px 10px;text-align:center;}
.xor-table th{background:rgba(201,168,76,.12);color:var(--gold);}
.xor-table td{color:rgba(200,180,120,.85);}
.xor-table .xor-result td{color:var(--hint);font-weight:700;background:rgba(96,184,232,.07);}
.xor-table .bit1{color:var(--ok);}
.xor-table .bit0{color:rgba(138,106,42,.6);}
/* Tip boxes */
.tip-box{background:rgba(96,184,232,.06);border:1px solid rgba(96,184,232,.2);border-radius:8px;padding:11px 13px;margin:10px 0;font-size:.78rem;color:rgba(160,216,240,.9);line-height:1.7;user-select:text;}
.tip-box .tip-title{font-family:'Orbitron',monospace;font-size:.54rem;color:var(--hint);letter-spacing:.12em;text-transform:uppercase;margin-bottom:6px;}
.warn-box{background:rgba(224,96,96,.06);border:1px solid rgba(224,96,96,.2);border-radius:8px;padding:11px 13px;margin:10px 0;font-size:.78rem;color:rgba(240,160,160,.9);line-height:1.7;user-select:text;}
.warn-box .warn-title{font-family:'Orbitron',monospace;font-size:.54rem;color:var(--err);letter-spacing:.12em;text-transform:uppercase;margin-bottom:6px;}
/* Strategy cards */
.strat-card{background:rgba(0,0,0,.38);border:1px solid rgba(138,106,42,.28);border-radius:12px;padding:15px 17px;margin:12px 0;}
.strat-card-head{display:flex;justify-content:space-between;align-items:center;margin-bottom:10px;}
.strat-card-name{font-family:'Orbitron',monospace;font-size:.65rem;color:var(--gold-light);letter-spacing:.1em;text-transform:uppercase;}
.strat-card-diff{font-family:'Orbitron',monospace;font-size:.5rem;padding:2px 7px;border-radius:4px;letter-spacing:.06em;}
.diff-basic{background:rgba(96,216,112,.15);color:var(--ok);border:1px solid rgba(96,216,112,.3);}
.diff-mid{background:rgba(201,168,76,.15);color:var(--gold);border:1px solid rgba(201,168,76,.3);}
.diff-adv{background:rgba(224,96,96,.15);color:var(--err);border:1px solid rgba(224,96,96,.25);}
.divider{height:1px;background:linear-gradient(90deg,transparent,rgba(138,106,42,.4),transparent);margin:24px 0;}

@media(max-width:820px){
  .main-layout{flex-direction:column;align-items:center;}
  .side-col{flex:none;width:100%;max-width:480px;flex-direction:row;flex-wrap:wrap;}
  .side-panel{flex:1 1 220px;}
  .stone{width:28px;height:28px;}
  .content-tab{padding:18px 14px;}
  .ct-cols{grid-template-columns:1fr;}
}