:root{--bg:#f5f1e8;--surface:#fff;--surface-2:#eef4e4;--text-primary:#232b33;--text-secondary:#5f6b76;--accent:#667d3f;--accent-hover:#556a34;--danger:#c0392b;--square-light:#e9dfbd;--square-dark:#7a8a4f;--last-move:#f8de7e99;--selected:#788c5073;--shadow:0 8px 30px #232b331f;--border:#d9d2c2;font-family:Inter,system-ui,-apple-system,sans-serif}*{box-sizing:border-box}body{background:var(--bg);color:var(--text-primary);min-height:100vh;margin:0}h1,h2,h3{font-family:Playfair Display,Georgia,serif;font-weight:600}#root{min-height:100vh}.app{max-width:1200px;margin:0 auto;padding:32px 24px}.app-header{text-align:center;margin-bottom:28px;position:relative}.app-header h1{letter-spacing:-.5px;margin:0 0 4px;font-size:2.4rem}.app-header p{color:var(--text-secondary);margin:0}.back-btn{align-items:center;gap:6px;margin:0;display:inline-flex;position:absolute;top:4px;left:0}@media (width<=600px){.back-btn{margin:0 auto 12px;position:static}}.layout{grid-template-columns:minmax(0,1fr) 320px;align-items:start;gap:32px;display:grid}@media (width<=900px){.layout{grid-template-columns:1fr}}.board-wrap{flex-direction:column;align-items:center;display:flex}.board{aspect-ratio:1;width:min(100%,560px);box-shadow:var(--shadow);border:2px solid var(--square-dark);-webkit-user-select:none;user-select:none;border-radius:12px;grid-template-rows:repeat(8,1fr);grid-template-columns:repeat(8,1fr);display:grid;overflow:hidden}.square{cursor:pointer;justify-content:center;align-items:center;display:flex;position:relative}.square.light{background:var(--square-light)}.square.dark{background:var(--square-dark)}.square.last-move{background:linear-gradient(135deg, var(--last-move), var(--last-move))}.square.selected{background:var(--selected)!important}.square.check{background:radial-gradient(circle,#c0392be6 0%,#c0392b59 60%,#0000 100%)!important}.square.legal{cursor:pointer}.legal-dot{pointer-events:none;background:#1f293740;border-radius:50%;width:26%;height:26%;position:absolute}.legal-ring{pointer-events:none;border-radius:6px;position:absolute;inset:0;box-shadow:inset 0 0 0 4px #4a6fa58c}.piece{pointer-events:none;justify-content:center;align-items:center;width:100%;height:100%;display:flex}.piece span{filter:drop-shadow(0 2px 2px #00000059);font-family:Segoe UI Symbol,Segoe UI,sans-serif;font-size:min(9vw,52px);line-height:1;display:block}.piece.white span{color:#fff;text-shadow:-1px -1px #5a693c99,1px -1px #5a693c99,-1px 1px #5a693c99,1px 1px #5a693c99,0 2px 3px #00000040}.piece.black span{color:#16181d;transform:rotate(180deg)}.coord{color:#0000008c;pointer-events:none;font-size:11px;font-weight:600;position:absolute}.coord.file{bottom:3px;right:5px}.coord.rank{top:3px;left:5px}.coord.on-dark{color:#ffffffbf}.controls{flex-wrap:wrap;justify-content:center;gap:12px;margin-top:20px;display:flex}.difficulty-group{border:1px solid var(--accent);border-radius:8px;display:inline-flex;overflow:hidden}.difficulty-btn{background:var(--surface);color:var(--text-secondary);cursor:pointer;border:none;padding:9px 16px;font-size:.9rem;font-weight:600;transition:background .15s,color .15s}.difficulty-btn+.difficulty-btn{border-left:1px solid var(--accent)}.difficulty-btn.active{background:var(--accent);color:#fff}.btn{cursor:pointer;background:var(--accent);color:#fff;border:none;border-radius:8px;margin:4px;padding:9px 18px;font-size:.9rem;font-weight:600;transition:background .15s}.btn:hover{background:var(--accent-hover)}.btn.secondary{background:var(--surface);color:var(--text-primary);border:1px solid var(--border)}.btn.secondary:hover{background:var(--surface-2)}.side-panel{flex-direction:column;gap:20px;display:flex}.card{background:var(--surface);box-shadow:var(--shadow);border-radius:12px;padding:18px 20px}.card h3{margin:0 0 10px;font-size:1.05rem}.turn-indicator{align-items:center;gap:14px;display:flex}.turn-marker{border:2px solid var(--border);border-radius:50%;width:18px;height:18px}.turn-marker.white{background:#fff}.turn-marker.black{background:#222}.turn-marker.active{box-shadow:0 0 0 4px var(--selected)}.captured{align-items:center;gap:6px;min-height:30px;display:flex}.captured .piece-label{font-size:1.2rem}.captured-label{color:var(--text-secondary);font-size:.85rem}.move-history{max-height:220px;color:var(--text-secondary);font-family:Inter,monospace;font-size:.9rem;line-height:1.6;overflow-y:auto}.move-history .row{align-items:center;display:flex}.move-history .num{width:34px;color:var(--text-secondary);font-weight:600}.panel-actions{grid-template-columns:1fr 1fr;gap:10px;display:grid}.dialog-overlay,.game-over-overlay{z-index:20;background:#1f293773;justify-content:center;align-items:center;display:flex;position:fixed;inset:0}.dialog,.game-over-card{background:var(--surface);box-shadow:var(--shadow);text-align:center;border-radius:14px;padding:24px 28px}.dialog h3{margin:0 0 16px}.promotion-options{justify-content:center;gap:12px;margin-bottom:18px;display:flex}.promotion-option{border:1px solid var(--border);background:var(--surface);cursor:pointer;border-radius:10px;justify-content:center;align-items:center;width:64px;height:64px;font-size:2.6rem;line-height:1;transition:background .15s,transform .1s;display:flex}.promotion-option:hover{background:var(--surface-2);transform:scale(1.06)}.promotion-option .white{color:#fff;text-shadow:-1px -1px #5a693c99,1px -1px #5a693c99,-1px 1px #5a693c99,1px 1px #5a693c99}.promotion-option .black{color:#16181d;transform:rotate(180deg)}.game-over-card h2{margin:0 0 8px;font-size:1.6rem}.game-over-card p{color:var(--text-secondary);margin:0 0 18px}.game-over-actions{justify-content:center;gap:10px;display:flex}.landing{justify-content:center;align-items:center;min-height:100vh;padding:32px 24px;display:flex}.landing-card{background:var(--surface);box-shadow:var(--shadow);text-align:center;border-radius:16px;width:100%;max-width:560px;padding:40px 44px}.landing-card h1{letter-spacing:-.5px;margin:0 0 6px;font-size:2.8rem}.landing-subtitle{color:var(--text-secondary);margin:0 0 28px}.mode-options{flex-direction:column;gap:14px;display:flex}.mode-card{text-align:left;border:1px solid var(--border);background:var(--surface);color:var(--text-primary);cursor:pointer;border-radius:12px;flex-direction:column;align-items:flex-start;gap:6px;padding:20px 24px;transition:border-color .15s,background .15s,transform .1s;display:flex}.mode-card:hover{border-color:var(--accent);background:var(--surface-2);transform:translateY(-2px)}.mode-icon{color:var(--accent);font-size:2.2rem;line-height:1}.mode-title{font-family:Playfair Display,Georgia,serif;font-size:1.15rem;font-weight:700}.mode-desc{color:var(--text-secondary);font-size:.9rem}.review-bar{background:var(--surface);box-shadow:var(--shadow);border-radius:12px;flex-wrap:wrap;justify-content:center;align-items:center;gap:16px;width:min(100%,560px);margin-top:16px;padding:12px 18px;display:flex}.review-nav{align-items:center;gap:12px;display:inline-flex}.review-counter{text-align:center;min-width:90px;font-size:.95rem;font-weight:600}.review-bar .btn:disabled{opacity:.5;cursor:not-allowed}.review-done{position:static}.rating-badge{letter-spacing:.3px;text-transform:uppercase;border-radius:999px;align-items:center;gap:6px;padding:5px 12px;font-size:.85rem;font-weight:700;display:inline-flex}.rating-loss{opacity:.8;font-weight:600}.rating-badge.brilliant{color:#0f7b3a;background:#d4f5e3}.rating-badge.good{color:#1d6ba8;background:#e3f0fa}.rating-badge.inaccuracy{color:#b8860b;background:#fdf3d7}.rating-badge.mistake{color:#c0562f;background:#fde8e0}.rating-badge.blunder{color:#c03028;background:#fbe0e0}