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var(--border);background:var(--card);cursor:pointer;border-radius:50%;flex-shrink:0;justify-content:center;align-items:center;width:40px;height:40px;transition:all .15s;display:flex}.back-btn:active{transform:scale(.93)}.setup-title{font-family:var(--font-display);font-size:18px;font-weight:700}.setup-section{margin-bottom:14px}.setup-label{font-family:var(--font-display);color:var(--text-light);text-transform:uppercase;letter-spacing:1.5px;text-align:center;margin-top:4px;margin-bottom:8px;font-size:11px;font-weight:600}.op-grid{grid-template-columns:repeat(4,1fr);gap:6px;display:grid}.op-btn{border:2px solid var(--border);background:var(--card);border-radius:var(--radius-sm);font-family:var(--font-display);color:var(--text-secondary);cursor:pointer;text-align:center;padding:8px;font-size:16px;font-weight:700;transition:all 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.15s;display:flex}.num-btn.selected{border-color:var(--accent);background:var(--accent-light);color:var(--accent)}.num-btn.bonus{border-style:dashed}.num-btn.bonus.selected{border-style:solid}.num-btn:active{transform:scale(.93)}.mode-row{gap:8px;display:flex}.mode-tab{border:2px solid var(--border);background:var(--card);border-radius:var(--radius-sm);font-family:var(--font-display);color:var(--text);cursor:pointer;flex-direction:column;flex:1;align-items:center;gap:4px;padding:10px;font-size:13px;font-weight:700;transition:all .15s;display:flex}.mode-tab-icon{color:var(--text-secondary);justify-content:center;align-items:center;display:flex}.mode-tab-icon svg{width:18px;height:18px}.mode-tab.selected{border-color:var(--accent);background:var(--accent-light);color:var(--accent)}.mode-tab.selected .mode-tab-icon{color:var(--accent)}.mode-tab:active{transform:scale(.98)}.mode-subtitle{color:var(--text-secondary);text-align:center;margin:8px 0 0;font-size:12px}.mode-value-picker{background:var(--card);border:1.5px solid var(--border);border-radius:var(--radius-sm);align-items:center;gap:12px;margin-top:12px;padding:12px 16px;display:none}.mode-value-picker.visible{display:flex}.mode-value-picker label{color:var(--text-secondary);white-space:nowrap;font-size:14px;font-weight:600}.stepper{flex:1;align-items:center;gap:0;max-width:160px;display:flex}.stepper-btn{border:1.5px solid var(--border);background:var(--card);width:44px;min-width:44px;height:44px;color:var(--text);cursor:pointer;-webkit-tap-highlight-color:transparent;flex-shrink:0;justify-content:center;align-items:center;font-family:inherit;font-size:24px;font-weight:700;line-height:1;transition:background .15s;display:flex}.stepper-btn:first-child{border-right:none;border-radius:8px 0 0 8px}.stepper-btn:last-child{border-left:none;border-radius:0 8px 8px 0}.stepper-btn:active{background:var(--accent-light);color:var(--accent)}.mode-value-picker input,.stepper input{border:1.5px solid var(--border);width:60px;min-width:0;height:44px;line-height:42px;font-family:var(--font-display);text-align:center;color:var(--text);appearance:textfield;box-sizing:border-box;border-left:none;border-right:none;border-radius:0;outline:none;flex:1;padding:0 8px;font-size:18px;font-weight:700}.mode-value-picker input::-webkit-outer-spin-button{-webkit-appearance:none;margin:0}.mode-value-picker input::-webkit-inner-spin-button{-webkit-appearance:none;margin:0}.stepper:focus-within .stepper-btn,.stepper:focus-within input{border-color:var(--accent)}.go-btn{background:var(--accent);color:#fff;border-radius:var(--radius);width:100%;font-family:var(--font-display);cursor:pointer;border:none;justify-content:center;align-items:center;gap:10px;margin-top:auto;margin-bottom:8px;padding:14px 24px;font-size:18px;font-weight:700;transition:transform .15s,box-shadow .15s;display:flex;box-shadow:0 4px 16px #4f6df54d}.go-btn:active{transform:scale(.97)}.flash-screen{background:var(--bg);z-index:5;flex-direction:column;display:flex;position:fixed;inset:0;overflow:hidden;padding:0!important}.flash-top-bar{z-index:10;background:var(--bg);justify-content:space-between;align-items:center;padding:24px 20px 12px;display:flex;position:fixed;top:0;left:0;right:0}.quit-btn{cursor:pointer;background:#0000000d;border:none;border-radius:50%;justify-content:center;align-items:center;width:40px;height:40px;transition:all .15s;display:flex}.quit-btn:active{transform:scale(.9)}.flash-timer,.flash-progress,.flash-score-display{font-family:var(--font-display);font-size:14px;font-weight:700}.flash-timer,.flash-progress{color:var(--text-light)}.flash-elapsed{align-items:center;gap:4px;display:inline-flex}.flash-elapsed-icon{width:16px;height:16px}.flash-score-display{color:var(--accent)}.card-container{flex:1;justify-content:center;align-items:flex-start;padding:88px 20px 20px;display:flex;position:relative;overflow:hidden}.flash-watermark{opacity:.15;pointer-events:none;z-index:0;position:absolute;top:380px;left:50%;transform:translate(-50%)}.flash-card{background:var(--card);width:100%;max-width:340px;box-shadow:var(--shadow-lg);text-align:center;border-radius:24px;padding:40px 24px 32px;transition:background .25s;position:relative}.flash-card.correct{background:var(--green-light)}.flash-card.hidden{opacity:0}.flash-card.slide-out{animation:.35s cubic-bezier(.4,0,.2,1) forwards slideOutLeft}.flash-card.slide-in{animation:.3s forwards fadeIn}@keyframes slideOutLeft{0%{opacity:1;transform:translate(0)}to{opacity:0;transform:translate(-120%)rotate(-8deg)}}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}.flash-card.wrong{animation:.4s shake}@keyframes shake{0%,to{transform:translate(0)}20%{transform:translate(-12px)}40%{transform:translate(12px)}60%{transform:translate(-8px)}80%{transform:translate(8px)}}.card-problem{font-family:var(--font-display);color:var(--text);letter-spacing:-1px;margin-bottom:24px;font-size:48px;font-weight:900;line-height:1.2}.card-operator{color:var(--accent);margin:0 4px}.card-input-row{justify-content:center;align-items:center;gap:12px;display:flex}.card-equals{font-family:var(--font-display);color:var(--text-light);font-size:36px;font-weight:900}.card-input{border:3px solid var(--border);width:100px;font-family:var(--font-display);text-align:center;color:var(--text);background:var(--bg);border-radius:14px;outline:none;padding:12px 8px;font-size:36px;font-weight:900;transition:border-color .2s}.card-input:focus{border-color:var(--accent)}.card-input.correct{border-color:var(--green);color:var(--green)}.card-input.wrong{border-color:var(--red);color:var(--red)}.card-check-btn{border-radius:var(--radius);font-family:var(--font-display);color:#fff;background:var(--accent);cursor:pointer;-webkit-tap-highlight-color:transparent;border:none;padding:14px 24px;font-size:18px;font-weight:700;transition:opacity .2s}.card-check-btn:hover{opacity:.9}.card-check-btn:active{opacity:.8}.card-check-btn:disabled{opacity:.5;cursor:not-allowed}.card-hint-btn{border:2px solid var(--border);background:var(--card);width:36px;height:36px;font-family:var(--font-display);color:var(--text-light);cursor:pointer;z-index:2;border-radius:50%;justify-content:center;align-items:center;font-size:18px;font-weight:800;transition:all .15s;display:flex;position:absolute;top:12px;right:16px}.card-hint-btn:hover{border-color:var(--orange);color:var(--orange);background:var(--orange-light)}.card-hint-btn:active{transform:scale(.9)}.card-hint-btn:disabled{opacity:0;pointer-events:none}.flash-card.revealed{background:var(--orange-light)}.card-revealed-answer{border:3px solid var(--orange);width:100px;font-family:var(--font-display);text-align:center;color:var(--orange);background:var(--card);border-radius:14px;padding:12px 8px;font-size:36px;font-weight:900}.card-continue-btn{background:var(--orange)!important}.card-feedback{opacity:0;font-size:28px;transition:opacity .2s;position:absolute;top:16px;right:20px}.card-feedback.show{opacity:1}.card-feedback.correct-icon{color:var(--green)}.card-feedback.wrong-icon{color:var(--red)}.results-screen{text-align:center;align-items:center}.results-signup-btn{top:max(32px,env(safe-area-inset-top));z-index:50;background:var(--accent);color:#fff;font-family:var(--font-display);border-radius:20px;padding:6px 14px;font-size:13px;font-weight:700;text-decoration:none;position:absolute;right:12px}.results-top-bar{justify-content:flex-start;align-items:center;width:100%;padding:16px 0 0;display:flex}.results-header{padding:24px 0 4px}.results-emoji{margin-bottom:6px;font-size:40px}.results-title{font-family:var(--font-display);color:var(--text);font-size:18px;font-weight:800}.results-subtitle{color:var(--text-secondary);margin-top:2px;font-size:14px}.results-stats{grid-template-columns:1fr 1fr;gap:8px;width:100%;margin:16px 0;display:grid}.stat-card{background:var(--card);border-radius:var(--radius-sm);border:1.5px solid var(--border);padding:12px 10px}.stat-value{font-family:var(--font-display);color:var(--accent);font-size:22px;font-weight:900}.stat-value.green{color:var(--green)}.stat-value.red{color:var(--red)}.stat-value.orange{color:var(--orange)}.stat-label{color:var(--text-secondary);margin-top:4px;font-size:12px;font-weight:600}.results-actions{flex-direction:column;gap:10px;width:100%;margin-top:16px;padding-bottom:8px;display:flex}.results-btn{border-radius:var(--radius);font-family:var(--font-display);cursor:pointer;border:none;padding:14px 24px;font-size:18px;font-weight:700;transition:transform .15s}.results-btn:active{transform:scale(.97)}.results-btn.primary{background:var(--accent);color:#fff;box-shadow:0 4px 16px #4f6df54d}.results-btn.secondary{background:var(--card);color:var(--text);border:1.5px solid var(--border)}.modal-overlay{z-index:100;background:#0000004d;justify-content:center;align-items:flex-end;animation:.2s mathFadeIn;display:flex;position:fixed;inset:0}.modal-sheet{width:100%;max-width:var(--max-width);background:var(--bg);border-radius:24px 24px 0 0;max-height:75dvh;padding:24px 20px 40px;animation:.3s slideUp;overflow-y:auto}@keyframes slideUp{0%{transform:translateY(100%)}to{transform:translateY(0)}}.modal-handle{background:var(--border);border-radius:2px;width:36px;height:4px;margin:0 auto 20px}.modal-title{font-family:var(--font-display);margin-bottom:16px;font-size:20px;font-weight:800}.friend-search{border:1.5px solid var(--border);border-radius:var(--radius-sm);width:100%;font-family:var(--font-body);background:var(--card);outline:none;flex:1;min-width:0;margin-bottom:0;padding:12px 16px;font-size:15px}.friend-search:focus{border-color:var(--accent)}.friend-send-btn{border-radius:var(--radius-sm);font-family:var(--font-body);cursor:pointer;background:var(--accent);color:#fff;white-space:nowrap;border:none;padding:12px 20px;font-size:15px;font-weight:600;transition:opacity .15s}.friend-send-btn:active{transform:scale(.97)}.friend-send-btn:disabled{opacity:.6;cursor:default}.friend-item{border-bottom:1px solid var(--border);align-items:center;gap:12px;padding:10px 0;display:flex}.friend-item:last-child{border-bottom:none}.friend-status{border-radius:20px;flex-shrink:0;margin-left:auto;padding:4px 10px;font-size:12px;font-weight:600}.friend-status.added{background:var(--green-light);color:var(--green)}.friend-status.pending{background:var(--orange-light);color:var(--orange)}.friend-status-toggle{cursor:pointer;background:var(--orange-light);color:var(--orange);border:none;border-radius:20px;flex-shrink:0;margin-left:auto;padding:4px 10px;font-size:12px;font-weight:600;transition:background .15s,color .15s}.friend-status-toggle .friend-status-hover{display:none}.friend-status-toggle:hover{background:var(--red,#ff3b30);color:#fff}.friend-status-toggle:hover .friend-status-default{display:none}.friend-status-toggle:hover .friend-status-hover{display:inline}.friend-status-toggle:active{transform:scale(.95)}.friend-status-toggle:disabled{opacity:.6;cursor:default}.friend-status.add{background:var(--accent-light);color:var(--accent);cursor:pointer}.friend-status.remove{color:var(--text-light);cursor:pointer;background:0 0;padding:4px}.friend-status.remove:hover{color:var(--red)}.friend-actions{flex-shrink:0;gap:6px;margin-left:auto;display:flex}.friend-action-btn{cursor:pointer;border:none;border-radius:20px;padding:6px 12px;font-size:12px;font-weight:600;transition:transform .15s}.friend-action-btn:active{transform:scale(.95)}.friend-action-btn.accept{background:var(--green);color:#fff}.friend-action-btn.decline{background:var(--border);color:var(--text-secondary)}.friends-section-label{font-family:var(--font-display);color:var(--text-secondary);text-transform:uppercase;letter-spacing:.5px;margin:16px 0 8px;font-size:13px;font-weight:700}@property --tw-rotate-x{syntax:"*";inherits:false}@property --tw-rotate-y{syntax:"*";inherits:false}@property --tw-rotate-z{syntax:"*";inherits:false}@property --tw-skew-x{syntax:"*";inherits:false}@property --tw-skew-y{syntax:"*";inherits:false}@property --tw-space-y-reverse{syntax:"*";inherits:false;initial-value:0}@property --tw-border-style{syntax:"*";inherits:false;initial-value:solid}@property --tw-font-weight{syntax:"*";inherits:false}@property --tw-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-shadow-color{syntax:"*";inherits:false}@property --tw-shadow-alpha{syntax:"<percentage>";inherits:false;initial-value:100%}@property --tw-inset-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-inset-shadow-color{syntax:"*";inherits:false}@property --tw-inset-shadow-alpha{syntax:"<percentage>";inherits:false;initial-value:100%}@property --tw-ring-color{syntax:"*";inherits:false}@property --tw-ring-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-inset-ring-color{syntax:"*";inherits:false}@property --tw-inset-ring-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-ring-inset{syntax:"*";inherits:false}@property --tw-ring-offset-width{syntax:"<length>";inherits:false;initial-value:0}@property --tw-ring-offset-color{syntax:"*";inherits:false;initial-value:#fff}@property --tw-ring-offset-shadow{syntax:"*";inherits:false;initial-value:0 0 #0000}@property --tw-outline-style{syntax:"*";inherits:false;initial-value:solid}@property --tw-ease{syntax:"*";inherits:false}