:root{--sudoku-primary:#1e40af;--sudoku-secondary:#3b82f6;--sudoku-accent:#60a5fa;--sudoku-success:#059669;--sudoku-warning:#d97706;--sudoku-error:#dc2626;--sudoku-dark:#1e293b;--sudoku-light:#f8fafc;--sudoku-grid:#e2e8f0;--sudoku-number:#0f172a;--sudoku-hover:#dbeafe;--sudoku-gradient:linear-gradient(135deg, #1e40af 0%, #3b82f6 50%, #60a5fa 100%);--sudoku-card-shadow:0 4px 20px rgba(30, 64, 175, 0.15);--sudoku-border-radius:12px;--sudoku-transition:all 0.3s cubic-bezier(0.4, 0, 0.2, 1);--font-primary:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',Roboto,sans-serif;--font-mono:'Fira Code','SF Mono',Monaco,'Cascadia Code',monospace}*{box-sizing:border-box;max-width:100%}body{margin:0;padding:0;box-sizing:border-box;overflow-x:hidden;width:100%}.sudoku-game-info{background:var(--sudoku-gradient);min-height:100vh;font-family:var(--font-primary);line-height:1.6;color:var(--sudoku-dark);margin:0;padding:0;display:flex;flex-direction:column;width:100%;overflow-x:hidden}.sudoku-header{background:rgba(255,255,255,.95);backdrop-filter:blur(10px);padding:2rem 0;text-align:center;border-bottom:3px solid var(--sudoku-secondary);margin-bottom:2rem;position:relative}.sudoku-header::before{content:'';position:absolute;top:0;left:0;right:0;bottom:0;background:repeating-linear-gradient(45deg,transparent,transparent 10px,rgba(30,64,175,.03) 10px,rgba(30,64,175,.03) 20px);pointer-events:none}.sudoku-title{font-size:3.5rem;font-weight:800;background:var(--sudoku-gradient);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;margin-bottom:.5rem;position:relative;z-index:1;text-shadow:0 2px 4px rgba(0,0,0,.1)}.sudoku-subtitle{font-size:1.25rem;color:var(--sudoku-dark);font-weight:500;opacity:.8;position:relative;z-index:1}.content-wrapper{max-width:min(1200px,100vw);margin:0 auto;padding:clamp(20px,5vh,50px) clamp(15px,4vw,20px);box-sizing:border-box;width:100%}.breadcrumb{display:flex;align-items:center;gap:.5rem;font-size:.9rem;margin-bottom:2rem;padding:1rem;background:rgba(255,255,255,.9);border-radius:var(--sudoku-border-radius);backdrop-filter:blur(5px)}.breadcrumb a{color:var(--sudoku-secondary);text-decoration:none;transition:var(--sudoku-transition)}.breadcrumb a:hover{color:var(--sudoku-primary);text-decoration:underline}.breadcrumb-separator{color:var(--sudoku-grid);font-weight:700}.action-buttons{display:flex;gap:1rem;justify-content:center;margin-bottom:3rem;flex-wrap:wrap}.back-btn,.play-btn{padding:1rem 2rem;font-size:1.1rem;font-weight:600;border:none;border-radius:var(--sudoku-border-radius);cursor:pointer;transition:var(--sudoku-transition);display:flex;align-items:center;gap:.5rem;text-decoration:none;box-shadow:var(--sudoku-card-shadow)}.play-btn{background:var(--sudoku-gradient);color:#fff}.play-btn:hover{transform:translateY(-2px);box-shadow:0 8px 30px rgba(30,64,175,.3)}.back-btn{background:#fff;color:var(--sudoku-primary);border:2px solid var(--sudoku-secondary)}.back-btn:hover{background:var(--sudoku-hover);transform:translateY(-2px)}.instructions-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(350px,100%),1fr));gap:2rem;margin-bottom:3rem}.instruction-card{background:#fff;border-radius:var(--sudoku-border-radius);box-shadow:var(--sudoku-card-shadow);overflow:hidden;transition:var(--sudoku-transition);border:1px solid rgba(30,64,175,.1)}.instruction-card:hover{transform:translateY(-5px);box-shadow:0 8px 30px rgba(30,64,175,.2)}.card-header{background:var(--sudoku-gradient);color:#fff;padding:1.5rem;display:flex;align-items:center;gap:1rem}.card-icon{font-size:2rem;opacity:.9}.card-title{font-size:1.5rem;font-weight:700;margin:0}.card-content{padding:2rem}.card-content p{margin-bottom:1.5rem;color:var(--sudoku-dark)}.card-content ul{list-style:none;padding:0;margin:0}.card-content li{padding:.75rem 0;border-bottom:1px solid var(--sudoku-grid);position:relative;padding-left:2rem}.card-content li:last-child{border-bottom:none}.card-content li::before{content:'🔹';position:absolute;left:0;color:var(--sudoku-secondary)}.rules-showcase{background:var(--sudoku-light);border-radius:var(--sudoku-border-radius);padding:1.5rem;margin:1rem 0}.showcase-title{font-size:1.2rem;font-weight:600;color:var(--sudoku-primary);margin-bottom:1rem;text-align:center}.sudoku-example{display:grid;grid-template-columns:repeat(4,1fr);gap:2px;background:var(--sudoku-dark);border-radius:8px;padding:8px;margin:1rem auto;max-width:200px}.example-cell{background:#fff;display:flex;align-items:center;justify-content:center;aspect-ratio:1;font-family:var(--font-mono);font-weight:600;font-size:1.2rem;border-radius:4px;color:var(--sudoku-dark)}.example-cell.given{background:var(--sudoku-hover);color:var(--sudoku-primary);font-weight:700}.grid-sizes{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:1rem;margin:1rem 0}.size-card{background:var(--sudoku-light);border-radius:var(--sudoku-border-radius);padding:1rem;text-align:center;border:2px solid transparent;transition:var(--sudoku-transition)}.size-card:hover{border-color:var(--sudoku-secondary);background:#fff}.size-number{font-size:2rem;font-weight:700;color:var(--sudoku-primary);margin-bottom:.5rem;font-family:var(--font-mono)}.size-description{font-size:.9rem;color:var(--sudoku-dark);opacity:.8}.difficulty-levels{display:grid;grid-template-columns:repeat(auto-fit,minmax(150px,1fr));gap:1rem;margin:1rem 0}.difficulty-card{background:var(--sudoku-light);border-radius:var(--sudoku-border-radius);padding:1rem;text-align:center;position:relative;overflow:hidden}.difficulty-card::before{content:'';position:absolute;top:0;left:0;right:0;height:4px;transition:var(--sudoku-transition)}.difficulty-card.easy::before{background:var(--sudoku-success)}.difficulty-card.medium::before{background:var(--sudoku-warning)}.difficulty-card.hard::before{background:var(--sudoku-error)}.difficulty-card.expert::before{background:var(--sudoku-dark)}.difficulty-name{font-weight:600;margin-bottom:.5rem}.difficulty-desc{font-size:.9rem;opacity:.8}.tips-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(250px,1fr));gap:1rem;margin:1rem 0}.tip-card{background:var(--sudoku-light);border-radius:var(--sudoku-border-radius);padding:1.5rem;border-left:4px solid var(--sudoku-secondary);transition:var(--sudoku-transition)}.tip-card:hover{background:#fff;box-shadow:var(--sudoku-card-shadow)}.tip-title{font-weight:600;color:var(--sudoku-primary);margin-bottom:.5rem}.tip-description{font-size:.9rem;color:var(--sudoku-dark);opacity:.8}.highlight-box{background:linear-gradient(135deg,var(--sudoku-hover) 0,#fff 100%);border:2px solid var(--sudoku-secondary);border-radius:var(--sudoku-border-radius);padding:1.5rem;margin:1.5rem 0;text-align:center;font-weight:600;color:var(--sudoku-primary)}.number-showcase{display:flex;justify-content:center;gap:.5rem;flex-wrap:wrap;margin:1rem 0}.number-demo{width:40px;height:40px;background:var(--sudoku-secondary);color:#fff;display:flex;align-items:center;justify-content:center;border-radius:8px;font-family:var(--font-mono);font-weight:600;box-shadow:0 2px 8px rgba(30,64,175,.2)}@media (max-width:768px){.sudoku-title{font-size:2.5rem}.sudoku-subtitle{font-size:1rem}.instructions-grid{grid-template-columns:1fr;gap:1.5rem}.action-buttons{flex-direction:column;align-items:center}.back-btn,.play-btn{width:100%;max-width:300px;justify-content:center}.difficulty-levels,.grid-sizes{grid-template-columns:repeat(2,1fr)}.tips-grid{grid-template-columns:1fr}.sudoku-example{max-width:150px}.example-cell{font-size:1rem}}@media (max-width:480px){.content-wrapper{padding:0 .5rem}.sudoku-header{padding:1.5rem 1rem}.sudoku-title{font-size:2rem}.card-header{padding:1rem}.card-content{padding:1.5rem}.difficulty-levels,.grid-sizes{grid-template-columns:1fr}}@keyframes numberPulse{0%,100%{transform:scale(1)}50%{transform:scale(1.1)}}.number-demo:hover{animation:numberPulse .6s ease-in-out}.size-card:hover .size-number{transform:scale(1.1);transition:var(--sudoku-transition)}.difficulty-card:hover{transform:translateY(-2px);box-shadow:var(--sudoku-card-shadow)}@media (max-width:399px){.instructions-grid{grid-template-columns:1fr;gap:1.5rem}.content-wrapper{max-width:100%;padding:1rem .5rem}.instruction-card{margin:0;padding:1rem;border-radius:12px}.card-header{flex-direction:column;text-align:center;margin-bottom:1rem}.card-icon{margin:0 0 .5rem 0;font-size:2rem}.card-title{font-size:1.2rem}.breadcrumb{padding:.75rem 1rem;font-size:.8rem;margin-bottom:1rem}.action-buttons{margin:1.5rem 0;display:flex;flex-direction:column;gap:.75rem}.back-btn,.play-btn{width:100%;max-width:none;margin:0;padding:1rem 1.5rem;font-size:1rem}.sudoku-header{padding:1.5rem 0}.sudoku-title{font-size:clamp(1.5rem,5vw,2rem)}.sudoku-subtitle{font-size:clamp(.9rem,3vw,1.1rem)}.difficulty-grid,.size-showcase,.tips-grid{grid-template-columns:1fr;gap:1rem}.sudoku-grid{grid-template-columns:repeat(3,1fr);gap:2px;max-width:150px;margin:0 auto}.sudoku-cell{width:45px;height:45px;font-size:1rem}}