:root[data-theme="dark"]{--bg-primary:#061021;--bg-secondary:rgba(255,255,255,0.03);--bg-tertiary:rgba(255,255,255,0.05);--text-primary:#f5f5f5;--text-secondary:rgba(255,255,255,0.8);--text-muted:rgba(255,255,255,0.6);--border-color:rgba(255,255,255,0.1);--border-hover:rgba(255,255,255,0.2);--card-bg:rgba(255,255,255,0.03);--card-border:rgba(255,255,255,0.1);--card-hover-bg:rgba(255,255,255,0.05);--shadow-color:rgba(0,0,0,0.7);--overlay-bg:rgba(0,0,0,0.7)}:root[data-theme="light"]{--bg-primary:#ffffff;--bg-secondary:#f8f9fa;--bg-tertiary:#e9ecef;--text-primary:#1a1a1a;--text-secondary:#4a4a4a;--text-muted:#6c757d;--border-color:#dee2e6;--border-hover:#adb5bd;--card-bg:#ffffff;--card-border:#dee2e6;--card-hover-bg:#f8f9fa;--shadow-color:rgba(0,0,0,0.1);--overlay-bg:rgba(0,0,0,0.5)}[data-theme="dark"] body{background:var(--bg-primary);color:var(--text-primary)}[data-theme="light"] body{background:var(--bg-primary);color:var(--text-primary)}.theme-toggle-btn{background:var(--card-bg);border:1px solid var(--border-color);border-radius:50%;width:48px;height:48px;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:all 0.3s ease;padding:0;font-size:1.5rem}.theme-toggle-btn:hover{background:var(--card-hover-bg);border-color:var(--border-hover);transform:rotate(20deg)scale(1.1)}.theme-toggle-btn:active{transform:rotate(20deg)scale(0.95)}.theme-icon{display:block;line-height:1}.theme-toggle-floating{position:fixed;bottom:2rem;left:2rem;z-index:1000;box-shadow:0 4px 12px var(--shadow-color)}.theme-toggle-floating:hover{box-shadow:0 8px 20px var(--shadow-color)}[data-theme="light"] .card,[data-theme="light"] .puzzle-card,[data-theme="light"] .achievement-card{background:var(--card-bg);border-color:var(--card-border);color:var(--text-primary)}[data-theme="light"] .card:hover,[data-theme="light"] .puzzle-card:hover{background:var(--card-hover-bg);box-shadow:0 10px 30px var(--shadow-color)}[data-theme="light"] .hero{color:var(--text-primary)}[data-theme="light"] .eyebrow{color:var(--text-muted)}[data-theme="light"] .lede,[data-theme="light"] .section-heading p{color:var(--text-secondary)}[data-theme="light"] .share-modal-backdrop,[data-theme="light"] .achievement-notification{background:var(--overlay-bg);backdrop-filter:blur(4px)}[data-theme="light"] .share-modal-content{background:var(--card-bg);border-color:var(--card-border);color:var(--text-primary)}[data-theme="light"] .lights-board,[data-theme="light"] .kenken-board,[data-theme="light"] .sudoku-grid{background:var(--bg-secondary);box-shadow:0 20px 40px var(--shadow-color)}[data-theme="light"] .light-cell,[data-theme="light"] .kenken-cell,[data-theme="light"] .sudoku-cell{background:var(--card-bg);border-color:var(--border-color)}[data-theme="light"] .light-cell:hover,[data-theme="light"] .kenken-cell:hover,[data-theme="light"] .sudoku-cell:hover{background:var(--card-hover-bg)}[data-theme="light"] .info-panel{background:rgba(59,130,246,0.05);border-color:rgba(59,130,246,0.2)}[data-theme="light"] .stat-card{background:var(--card-bg);border-color:var(--card-border)}[data-theme="light"] .daily-challenge-card{background:var(--card-bg);border-color:var(--card-border)}[data-theme="light"] button,[data-theme="light"] .btn{background:var(--bg-tertiary);border-color:var(--border-color);color:var(--text-primary)}[data-theme="light"] button:hover,[data-theme="light"] .btn:hover{background:var(--card-hover-bg);border-color:var(--border-hover)}[data-theme="light"] code,[data-theme="light"] pre{background:var(--bg-secondary);color:var(--text-primary)}@media (max-width:768px){.theme-toggle-floating{bottom:1rem;left:1rem;width:44px;height:44px;font-size:1.25rem}}