:root{color-scheme:dark;--bg:#081729;--pane:#102940;--edge:#2d526f;--text:#e8eff7;--muted:#9eb4c9;--lightSq:#F0D9B5;--darkSq:#B58863}*{box-sizing:border-box}body{margin:0;min-height:100vh;font:15px/1.55 'Segoe UI',Arial,sans-serif;background:radial-gradient(ellipse at 40% -20%,#214365,transparent 47%),linear-gradient(135deg,#061322,#091c30 65%,#061222);color:var(--text)}a{color:inherit;text-decoration:none}button,select{font:inherit}button{cursor:pointer}button:focus-visible,a:focus-visible,select:focus-visible{outline:3px solid #d4e4f3;outline-offset:2px}header{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:16px;min-height:80px;padding:8px clamp(12px,3vw,45px);background:#08192bea;border-bottom:1px solid #40627a85}.brand{display:flex;align-items:center;gap:8px;font-size:25px;letter-spacing:-1px}.brand img{object-fit:contain}.brand .jere{color:#fff}.brand .chess{color:#8eacc7}nav{display:flex;flex-wrap:wrap;gap:15px;font-size:14px}nav a[aria-current]{color:white;border-bottom:2px solid #c3d1e1}.layout{max-width:1680px;margin:auto;padding:20px 16px;display:grid;grid-template-columns:minmax(215px,.77fr) minmax(320px,1.6fr) minmax(260px,1fr);gap:18px;align-items:start}.library,.details{padding:12px 8px}.eyebrow{font-size:11px;letter-spacing:.12em;text-transform:uppercase;color:#9cb9d0}h1{font-size:23px;margin:3px 0 6px}h2{font:600 clamp(22px,2vw,29px) Georgia,serif;margin:7px 0 14px}h3{font-size:14px;margin:19px 0 6px}p{margin:8px 0}.subtitle{font-size:12px;color:var(--muted)}.filters{display:grid;grid-template-columns:1fr 1fr;gap:8px;margin:17px 0}.filters label{font-size:12px;color:var(--muted)}select{width:100%;padding:8px 5px;border:1px solid #526c85;border-radius:7px;background:#102b46;color:#fff;margin-top:5px}.opening-list{max-height:70vh;overflow:auto}.opening-group{border-top:1px solid #35526d}.group-button,.opening-option{display:block;width:100%;text-align:left;background:transparent;color:#dce6ef;border:0;padding:11px 7px}.group-button{font-weight:650}.opening-option{padding-left:20px;border-left:2px solid transparent;font-size:13px}.opening-option:hover,.group-button:hover{background:#1b3a53}.opening-option.active{border-left-color:#c3d1e1;background:#1d3853}.opening-option small{display:block;color:#9eb4c9;font-size:11px}.group-lines[hidden]{display:none}.board-area{min-width:0}.board-shell{width:100%;max-width:700px;margin:0 auto;background:#09182b;padding:8px;border:1px solid #355c7b;border-radius:7px}.board{display:grid;grid-template-columns:repeat(8,minmax(0,1fr));aspect-ratio:1;border:2px solid #0a1420}.square{position:relative;min-width:0;aspect-ratio:1;border:0;border-radius:0;display:flex;align-items:center;justify-content:center;padding:0;touch-action:manipulation}.light{background:var(--lightSq)}.dark{background:var(--darkSq)}.square.selected{outline:4px solid #ff4fcf;outline-offset:-4px;box-shadow:inset 0 0 0 999px #ff4fcf22}.square.legal:after{content:'';position:absolute;width:25%;height:25%;border-radius:50%;background:#ff4fcfb0}.square.last{box-shadow:inset 0 0 0 999px #f3ef5d39}.piece{width:90%;height:90%;object-fit:contain;pointer-events:none;user-select:none}.coord-rank,.coord-file{position:absolute;z-index:1;pointer-events:none;font:700 clamp(9px,1.1vw,12px) Arial}.coord-rank{top:4px;left:5px}.coord-file{bottom:3px;right:5px}.light .coord-rank,.light .coord-file{color:var(--darkSq)}.dark .coord-rank,.dark .coord-file{color:var(--lightSq)}.controls{display:flex;justify-content:center;gap:9px;flex-wrap:wrap;margin:14px 0}.controls button{padding:9px 13px;background:#102b46;color:#edf5ff;border:1px solid #4a7191;border-radius:8px}.controls button:hover{background:#1c466a}.center-note{text-align:center}.details{padding:14px}.details p,.details li{color:#c4d4e2;line-height:1.65}.details ul{padding-left:20px}.line{height:1px;background:#55718b70;margin:20px 0}.progress-top{display:flex;justify-content:space-between;color:#bdd0e2;font-size:12px}.track{height:4px;background:#34516a;margin-top:8px}.track div{height:100%;width:0;background:#c3d0df}#feedback{padding:12px;border-left:3px solid #a6c0d8;background:#162f48;margin-top:20px;border-radius:5px}#feedback.good{border-color:#9dd9bc;color:#b5e7d1}#feedback.bad{border-color:#eab4a9;color:#f3c6be}@media(max-width:1100px){.layout{grid-template-columns:minmax(200px,.65fr) minmax(340px,1.4fr)}.details{grid-column:1/-1}}@media(max-width:720px){header{padding:8px 12px}.layout{display:flex;flex-direction:column;gap:10px;padding:10px 8px}.board-area{order:1;width:100%}.library{order:2;width:100%}.details{order:3;width:100%}.opening-list{max-height:340px}.board-shell{padding:3px}.controls button{font-size:13px;padding:8px}.brand{font-size:21px}.brand img{width:42px;height:42px}.filters{margin:10px 0}}

/* Academia: mismos espacios, cabecera, panel lateral y tutor de Lecciones Básicas */
.opening-wrap{max-width:1720px;margin:0 auto;padding:18px clamp(10px,2vw,32px) 26px}.back-link{max-width:1440px;margin:0 auto 8px;font-size:13px;color:#bbd5ed}.layout{max-width:unset;padding:0;grid-template-columns:minmax(205px,.71fr) minmax(330px,1.68fr) minmax(280px,1.18fr);gap:14px}.library{padding:12px 2px 12px 0;background:transparent;border:0}.library h1{font-size:22px;font-weight:600}.board-area{padding:12px;border:1px solid #2d526f;border-radius:14px;background:linear-gradient(135deg,#102940e8,#08192be8);display:flex;flex-direction:column;gap:11px}.board-shell{max-width:760px;padding:10px 12px 12px;border-radius:11px}.controls{gap:7px}.controls button{min-height:36px;padding:8px 13px;border-radius:8px}.details{padding:14px 16px 16px;min-width:0}.right-heading{margin-bottom:8px}.mode-label,.lesson-kicker{font-size:10px;color:#92b4d0;letter-spacing:.12em;font-weight:650}.tutor-side-wrap{display:flex;align-items:flex-start;gap:12px;margin-top:4px}.tutor-side-img{width:108px;height:160px;object-fit:contain;object-position:center bottom;flex-shrink:0;filter:drop-shadow(0 8px 14px #0005)}.tutor-side-content{display:flex;flex:1;flex-direction:column;gap:8px;min-width:0}.tutor-side-content h2{font:600 clamp(19px,1.45vw,25px) Georgia,serif;line-height:1.14;margin:0 0 2px;color:#e6eef7}.tutor-side-bubble{position:relative;border-radius:18px 18px 18px 8px;padding:16px 18px;background:linear-gradient(180deg,#f4f7fa,#d7e1ea);border:1px solid #b7c4d0;color:#24547f;box-shadow:0 8px 22px #0003}.tutor-side-bubble:before{content:'';position:absolute;left:-12px;top:38px;border-width:10px 12px 10px 0;border-style:solid;border-color:transparent #d7e1ea transparent transparent}.tutor-side-bubble p{color:#24547f;margin:0;font-size:15px;line-height:1.75}.tutor-mini-inline{margin-top:2px;padding-top:10px;border-top:1px solid #aec0d140}.tutor-mini-inline p{font-size:13px;line-height:1.6}.tutor-mini-inline ul{margin:7px 0;padding-left:20px;font-size:13px}.tutor-mini-inline #feedback{margin-top:10px}.right-footer{margin-top:14px;padding-top:12px;border-top:1px solid #6f8ca43b;display:flex;justify-content:space-between;gap:10px;flex-wrap:wrap;color:#809ab0;font-size:11px}.track{margin-top:7px}.opening-list{max-height:68vh}.board-area .board{border-radius:2px}@media(max-width:1150px){.layout{grid-template-columns:minmax(210px,.78fr) minmax(320px,1.45fr)}.details{grid-column:1/-1}.tutor-side-wrap{display:grid;grid-template-columns:100px 1fr}}@media(max-width:680px){.opening-wrap{padding:10px 8px}.layout{display:flex;flex-direction:column;gap:8px}.library{order:0;width:100%;padding:4px 8px}.opening-list{max-height:240px}.board-area{order:1;width:100%;padding:5px;border:0;background:none}.board-shell{width:100%;padding:5px}.details{order:2;padding:12px 10px}.tutor-side-wrap{grid-template-columns:70px 1fr;gap:8px}.tutor-side-img{width:70px;height:110px}.tutor-side-bubble{padding:10px 12px}.tutor-side-bubble p{font-size:13px}}

/* Fase 2: ajustes de distribución respetando el diseño de Academia */
.back-link,.academy-side-header{display:none}
.opening-wrap{padding-top:18px}
.library{padding-top:4px}
.right-heading{margin-bottom:14px}
.right-heading h2{margin:0 0 3px;font:600 clamp(20px,1.55vw,26px) Georgia,serif;line-height:1.2;color:#e6eef7}
.right-heading .mode-label{display:block}
.tutor-side-wrap{display:flex;align-items:center;gap:14px}
.tutor-side-content{flex:1;min-width:0}
.tutor-side-img{height:150px}
.tutor-info{width:100%;margin-top:12px}
.tutor-info .tutor-mini-inline{padding-top:12px;margin-top:10px}
@media(max-width:1150px){.tutor-side-wrap{display:flex}}
@media(max-width:680px){.opening-wrap{padding-top:10px}.tutor-side-wrap{display:flex;gap:8px}.tutor-side-img{height:110px}}

/* Fase 3: selectores dependientes en escritorio y móvil */
.opening-pickers{display:grid;grid-template-columns:1fr;gap:12px;margin-top:16px}
.opening-pickers label{display:block;font-size:12px;color:var(--muted)}
.opening-pickers select{display:block;max-width:100%;min-width:0;margin-top:5px;padding:10px 8px}
.library{min-width:0}
.tutor-side-bubble{height:154px;min-height:154px;overflow-y:auto;overflow-x:hidden;scrollbar-width:thin;overscroll-behavior:contain}
.tutor-side-bubble p{overflow-wrap:anywhere}
@media(max-width:680px){
 .opening-pickers{gap:8px;margin-top:10px}
 .library{padding-bottom:8px}
 .tutor-side-bubble{height:126px;min-height:126px;padding:10px 12px}
 .tutor-side-bubble p{font-size:12px;line-height:1.55}
}

/* Fase 4 — selector plegable y tutor encima del tablero en móvil */
.mobile-opening-toggle{display:none}
@media(max-width:680px){
 .layout{display:flex;flex-direction:column;gap:8px}
 .library{order:0;width:100%}
 .details{order:1;width:100%;padding:8px 10px}
 .board-area{order:2;width:100%}
 .library h1{margin:2px 0 3px}
 .mobile-opening-toggle{display:flex;align-items:center;justify-content:space-between;width:100%;margin-top:10px;padding:9px 12px;color:#e8eff7;background:#102b46;border:1px solid #526c85;border-radius:8px;font-weight:600}
 .mobile-opening-toggle[aria-expanded="true"]{background:#1b3a53}
 .mobile-opening-options{display:none;padding-top:4px}
 .mobile-opening-options.is-open{display:block}
 .tutor-side-wrap{display:flex;align-items:center}
 .tutor-side-bubble{height:126px;min-height:126px}
 .tutor-info{margin-top:10px}
}


/* Fase 5: tablero protagonista; datos auxiliares bajo el tablero, en todas las pantallas */
.layout{grid-template-areas:"library board tutor" "library extra extra";grid-template-rows:auto auto;align-items:start}
.library{grid-area:library}
.board-area{grid-area:board}
.details{grid-area:tutor}
.training-extra{grid-area:extra;min-width:0;padding:14px 18px 16px;background:linear-gradient(135deg,#102940e8,#08192be8);border:1px solid #2d526f;border-radius:14px}
.training-extra .tutor-info{margin-top:0;display:grid;grid-template-columns:minmax(0,1fr) minmax(0,1fr);gap:24px}
.training-extra .tutor-mini-inline{margin-top:0}
.training-extra .right-footer{margin-top:10px}
.library{padding-top:4px}
.details .tutor-side-wrap{margin-top:6px}
@media(max-width:1150px) and (min-width:681px){
 .layout{grid-template-areas:"library board" "tutor tutor" "extra extra";grid-template-columns:minmax(210px,.78fr) minmax(320px,1.45fr)}
 .details{grid-column:auto}
}
@media(max-width:680px){
 .layout{display:flex;flex-direction:column;gap:8px}
 .library{order:0;padding:0 8px 4px}
 .details{order:1;padding:5px 10px 2px}
 .board-area{order:2}
 .training-extra{order:3;width:100%;padding:12px 14px}
 .training-extra .tutor-info{display:block}
 .training-extra .tutor-mini-inline+.tutor-mini-inline{margin-top:12px}
 .mobile-opening-toggle{margin-top:0}
 .details .right-heading{margin-bottom:8px}
 .tutor-side-wrap{margin-top:0}
}

/* Fase 6: complementos bajo el tutor en escritorio; móvil sin cambios */
@media(min-width:681px){
 .layout{grid-template-areas:"library board tutor";grid-template-rows:auto;align-items:start}
 .right-column{grid-area:tutor;display:flex;flex-direction:column;min-width:0;gap:4px}
 .right-column .details{grid-area:auto;grid-column:auto}
 .right-column .training-extra{grid-area:auto;width:100%;padding:0 16px 12px;background:none;border:0;border-radius:0}
 .right-column .training-extra .tutor-info{display:block;margin-top:0}
 .right-column .training-extra .tutor-mini-inline{border-top:0;padding-top:4px;margin-top:8px}
 .right-column .training-extra .tutor-mini-inline+.tutor-mini-inline{margin-top:16px}
 .right-column .training-extra .right-footer{margin-top:12px}
}
@media(max-width:680px){
 .right-column{display:contents}
}

@media(min-width:681px) and (max-width:1150px){
 .layout{grid-template-areas:"library board" "tutor tutor";grid-template-columns:minmax(210px,.78fr) minmax(320px,1.45fr)}
}

/* Fase 7: ventana de finalización original de Academia, aislada del tablero. */
.tutor-finish{position:fixed;inset:0;background:#020912d8;z-index:10000;display:flex;align-items:center;justify-content:center;padding:14px}
.tutor-finish[hidden]{display:none!important}
.tutor-dialog{width:min(440px,96vw);max-height:95dvh;overflow-y:auto;background:#0f2237;border:1px solid #587896;border-radius:18px;padding:18px;color:#f1f5fa;box-shadow:0 25px 90px #000a}
.tutor-dialog-head{display:flex;align-items:flex-start;gap:10px}
.tutor-dialog-head img{object-fit:contain;object-position:center bottom;width:130px;height:162px;flex-shrink:0;filter:drop-shadow(0 8px 14px rgba(0,0,0,.28))}
.tutor-popup-bubble{position:relative;border-radius:18px 18px 18px 8px;padding:14px 16px;box-shadow:0 8px 22px #0003;flex:1;min-width:0;background:linear-gradient(180deg,#f4f7fa 0%,#d7e1ea 100%);border:1px solid #b7c4d0;color:#24547f}
.tutor-popup-bubble:before{content:'';position:absolute;left:-12px;top:34px;border-width:10px 12px 10px 0;border-style:solid;border-color:transparent #d7e1ea transparent transparent;filter:drop-shadow(-1px 0 0 #b7c4d0)}
.tutor-popup-bubble h2{font:600 23px Georgia,serif;color:#bb8c34;margin:0 0 8px;line-height:1.17}
.tutor-popup-bubble p{font-size:14px;line-height:1.6;color:#24547f;margin:0}
.tutor-dialog-actions{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;margin-top:14px}
.tutor-dialog-actions .btn{min-height:45px;cursor:pointer;background:#102b46;border:1px solid #4a7191;border-radius:8px;color:#edf5ff;padding:10px}
.tutor-dialog-actions .btn.primary{background:#d7e4ef;color:#102940;font-weight:650}
.tutor-dialog-actions .btn:focus-visible{outline:3px solid #d4e4f3;outline-offset:2px}
@media(max-width:680px){.tutor-dialog-head img{width:95px;height:125px}.tutor-dialog-actions{grid-template-columns:1fr}.tutor-popup-bubble h2{font-size:20px}}
@media(prefers-reduced-motion:reduce){.tutor-finish *{animation:none!important;transition:none!important}}