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var(--spacing-sm)}@media(min-width:768px){.responsive-container{max-width:var(--container-tablet);padding:0 var(--spacing-md)}}@media(min-width:1024px){.responsive-container{max-width:var(--container-desktop);padding:0 var(--spacing-lg)}}.touch-button{min-height:var(--touch-target-min);padding:var(--spacing-sm) var(--spacing-md);border-radius:var(--radius-md);border:none;font-weight:500;display:inline-flex;align-items:center;justify-content:center;gap:var(--spacing-xs)}.mobile-scroll{-webkit-overflow-scrolling:touch;overflow-y:auto;overscroll-behavior:contain}.safe-area-bottom{padding-bottom:env(safe-area-inset-bottom,0)}.safe-area-top{padding-top:env(safe-area-inset-top,0)}.flex-center{display:flex;align-items:center;justify-content:center}.flex-between{display:flex;align-items:center;justify-content:space-between}.flex-col{display:flex;flex-direction:column}.flex-wrap{flex-wrap:wrap}.gap-xs{gap:var(--spacing-xs)}.gap-sm{gap:var(--spacing-sm)}.gap-md{gap:var(--spacing-md)}.gap-lg{gap:var(--spacing-lg)}.text-center{text-align:center}.text-muted{color:var(--text-secondary)}.text-xs{font-size:var(--font-size-xs)}.text-sm{font-size:var(--font-size-sm)}.text-lg{font-size:var(--font-size-lg)}.text-xl{font-size:var(--font-size-xl)}@keyframes spin{0%{transform:rotate(0)}to{transform:rotate(360deg)}}.spin{animation:spin 1s linear infinite}@keyframes slideUp{0%{transform:translateY(100%);opacity:0}to{transform:translateY(0);opacity:1}}.bottom-sheet{animation:slideUp .3s ease-out}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.fade-in{animation:fadeIn .2s ease-out}.chess-board-container{display:flex;flex-direction:column;align-items:center;gap:var(--spacing-md);padding:var(--spacing-md);width:100%;max-width:100vw;overflow-x:hidden;box-sizing:border-box}.chess-board{border:2px solid #333;border-radius:var(--radius-sm);overflow:hidden;box-shadow:0 4px 12px #0006;margin:0 auto;max-width:100%}@media(max-width:767px){.chess-board-container{padding:var(--spacing-sm)}.game-view{width:100%;max-width:100vw;overflow-x:hidden}}.mobile-nav{position:fixed;bottom:0;left:0;right:0;height:64px;background:#1a1a1af2;backdrop-filter:blur(10px);-webkit-backdrop-filter:blur(10px);border-top:1px solid var(--color-border-primary);display:none;justify-content:space-around;align-items:center;padding:0 var(--space-sm);z-index:var(--z-modal);box-shadow:0 -2px 10px #0000004d}@media(max-width:767px){.mobile-nav{display:flex;animation:slide-up .3s ease}.app-container{padding-bottom:80px}}.mobile-nav-item{display:flex;flex-direction:column;align-items:center;justify-content:center;gap:var(--space-xs);padding:var(--space-sm) var(--space-md);background:none;border:none;color:var(--color-text-tertiary);cursor:pointer;transition:color var(--transition-base),transform var(--transition-fast);min-width:64px;min-height:var(--touch-target-comfortable);-webkit-tap-highlight-color:transparent;user-select:none}.mobile-nav-item.active{color:var(--color-primary)}.mobile-nav-item:active{transform:scale(.95)}.mobile-nav-icon{font-size:var(--font-size-2xl);line-height:1;display:block}.mobile-nav-label{font-size:var(--font-size-xs);font-weight:var(--font-weight-medium);line-height:1;display:block;white-space:nowrap}.chess-square{position:relative;display:flex;align-items:center;justify-content:center;cursor:pointer;transition:background-color .15s ease,box-shadow .15s ease,transform .1s ease;user-select:none;-webkit-user-select:none;-webkit-tap-highlight-color:transparent;touch-action:manipulation}.chess-square:active{transform:scale(.97)}.chess-square.selected{z-index:10}.chess-square.invalid{animation:flash-invalid .3s ease}@keyframes flash-invalid{0%,to{background-color:inherit}50%{background-color:#f009!important}}.chess-square.in-check{animation:pulse-check 1s ease-in-out infinite}@keyframes pulse-check{0%,to{box-shadow:inset 0 0 0 3px #ff0000e6}50%{box-shadow:inset 0 0 0 3px #f006}}.chess-square img{pointer-events:none;user-select:none;-webkit-user-select:none;-webkit-user-drag:none}@media(min-width:768px){.chess-square img{pointer-events:auto;cursor:grab}.chess-square img:active{cursor:grabbing}}.legal-move-dot,.legal-move-ring{pointer-events:none}@keyframes piece-appear{0%{opacity:.5;transform:scale(.85)}to{opacity:1;transform:scale(1)}}.chess-square.has-piece.last-move img{animation:piece-appear .2s ease}.mobile-lobby{padding:0 var(--space-lg) var(--space-lg);max-width:600px;margin:0 auto;width:100%}.lobby-card{background-color:var(--color-bg-secondary);border:1px solid var(--color-border-primary);border-radius:var(--radius-lg);padding:var(--space-xl);margin-bottom:var(--space-lg);box-shadow:var(--shadow-md)}.lobby-card h2,.lobby-card h3{margin:0 0 var(--space-lg) 0;font-size:var(--font-size-lg);font-weight:var(--font-weight-semibold);color:var(--color-text-primary)}.lobby-card-header{display:flex;align-items:center;gap:var(--space-md);margin-bottom:var(--space-lg)}.lobby-card-header h3{margin:0;font-size:var(--font-size-lg);font-weight:var(--font-weight-semibold)}.lobby-card-icon{font-size:var(--font-size-2xl);line-height:1}.time-control-selector{display:grid;grid-template-columns:repeat(3,1fr);gap:var(--space-sm);margin-bottom:var(--space-lg)}.time-control{background-color:var(--color-bg-tertiary);border:2px solid var(--color-border-secondary);border-radius:var(--radius-md);padding:var(--space-md) var(--space-sm);cursor:pointer;touch-action:manipulation;transition:all var(--transition-base);-webkit-tap-highlight-color:transparent;text-align:center;min-height:var(--touch-target-min)}.time-control:active{transform:scale(.97)}.time-control.active{background-color:var(--color-primary);border-color:var(--color-primary)}.time-control.active .time-label,.time-control.active .time-value{color:var(--color-bg-primary)}.time-label{font-size:var(--font-size-base);font-weight:var(--font-weight-bold);color:var(--color-text-primary);display:block}.time-control.active .time-label{color:var(--color-bg-primary)}.time-value{font-size:var(--font-size-sm);font-weight:var(--font-weight-bold);color:var(--color-text-primary)}.btn-lobby{width:100%;min-height:var(--button-height-lg);font-size:var(--font-size-base);font-weight:var(--font-weight-semibold);border-radius:var(--radius-md);border:none;cursor:pointer;transition:all var(--transition-base);-webkit-tap-highlight-color:transparent;display:flex;align-items:center;justify-content:center;gap:var(--space-sm)}.btn-lobby:active{transform:scale(.98)}.btn-lobby-primary{background-color:var(--color-primary);color:var(--color-bg-primary)}.btn-lobby-primary:active{background-color:var(--color-primary-dark)}.btn-lobby-primary:disabled{background-color:var(--color-bg-elevated);color:var(--color-text-disabled);cursor:not-allowed}.btn-lobby-secondary{background-color:var(--color-bg-elevated);color:var(--color-text-primary);border:1px solid var(--color-border-secondary)}.btn-lobby-secondary:active{background-color:var(--color-border-secondary)}.btn-lobby-secondary:disabled{opacity:.5;cursor:not-allowed}.lobby-button-group,.lobby-button-stack{display:flex;flex-direction:column;gap:var(--space-md)}.lobby-divider{text-align:center;color:var(--color-text-tertiary);font-size:var(--font-size-sm);margin:var(--space-xs) 0}.room-code-input{display:flex;gap:var(--space-sm)}.room-code-input input{flex:1;height:var(--input-height);background-color:var(--color-bg-tertiary);border:2px solid var(--color-border-secondary);border-radius:var(--radius-md);padding:0 var(--space-lg);color:var(--color-text-primary);font-size:var(--font-size-base);font-weight:var(--font-weight-semibold);text-align:center;text-transform:uppercase;letter-spacing:2px}.room-code-input input::placeholder{color:var(--color-text-disabled);text-transform:none;letter-spacing:normal;font-weight:var(--font-weight-regular)}.room-code-input input:focus{outline:none;border-color:var(--color-border-focus)}.room-code-input button{min-width:80px;height:var(--input-height)}.lobby-rating-display{margin:var(--space-md) 0 0 0;text-align:center;font-size:var(--font-size-sm);color:var(--color-text-secondary)}.puzzle-info{display:flex;justify-content:space-between;align-items:center;margin-bottom:var(--space-lg);padding:var(--space-md);background-color:var(--color-bg-tertiary);border-radius:var(--radius-md)}.puzzle-number{font-size:var(--font-size-sm);font-weight:var(--font-weight-semibold);color:var(--color-primary)}.puzzle-streak{font-size:var(--font-size-sm);font-weight:var(--font-weight-semibold);color:var(--color-text-primary)}.lobby-error-message{background-color:#ff6b6b1a;border:1px solid rgba(255,107,107,.3);color:var(--color-error);padding:var(--space-md);border-radius:var(--radius-md);margin-top:var(--space-md);font-size:var(--font-size-sm);text-align:center}.lobby-success-message{background-color:#81b64c1a;border:1px solid rgba(129,182,76,.3);color:var(--color-success);padding:var(--space-md);border-radius:var(--radius-md);margin-top:var(--space-md);font-size:var(--font-size-sm);text-align:center}.lobby-searching{display:flex;align-items:center;justify-content:center;gap:var(--space-sm);padding:var(--space-lg);background-color:var(--color-bg-tertiary);border-radius:var(--radius-md);margin-top:var(--space-md)}.lobby-searching-spinner{width:var(--space-xl);height:var(--space-xl);border:2px solid var(--color-border-secondary);border-top-color:var(--color-primary);border-radius:var(--radius-full);animation:spin 1s linear infinite}.variant-selector{display:grid;grid-template-columns:repeat(2,1fr);gap:var(--space-sm);margin-bottom:var(--space-lg)}.variant-option{background-color:var(--color-bg-tertiary);border:2px solid var(--color-border-secondary);border-radius:var(--radius-md);padding:var(--space-md);cursor:pointer;transition:all var(--transition-base);min-height:var(--touch-target-min);text-align:center;font-size:var(--font-size-sm);font-weight:var(--font-weight-medium);color:var(--color-text-secondary)}.variant-option:active{transform:scale(.97)}.variant-option.active,.variant-btn.active{background-color:var(--accent-purple);border-color:var(--accent-purple);color:var(--color-text-primary)}.variant-btn{background-color:var(--color-bg-tertiary);border:2px solid var(--color-border-secondary);border-radius:var(--radius-md);padding:var(--space-md);cursor:pointer;transition:all var(--transition-base);text-align:center;font-size:var(--font-size-sm);font-weight:var(--font-weight-medium);color:var(--color-text-secondary);-webkit-tap-highlight-color:transparent;min-height:var(--touch-target-min)}.variant-btn:active{transform:scale(.97)}.time-desc{font-size:var(--font-size-xs);color:var(--color-text-tertiary);display:block;margin-top:var(--space-xs)}.time-control.active .time-desc{color:var(--color-bg-secondary)}@media(min-width:768px){.mobile-lobby{display:none}}@media(max-width:767px){.desktop-lobby{display:none}}