.practice-layout{display:flex;flex-direction:column;min-height:100vh;background:var(--bg-secondary)}.practice-header{position:fixed;top:0;left:0;right:0;height:var(--header-height);background:var(--bg-primary);border-bottom:1px solid var(--border);display:flex;align-items:center;padding:0 var(--space-4);z-index:100}.practice-header-left{display:flex;align-items:center;gap:var(--space-3)}.practice-header-center{flex:1;display:flex;justify-content:center;align-items:center}.practice-header-right{display:flex;align-items:center;gap:var(--space-3)}.practice-title{font-size:var(--text-sm);font-weight:600;color:var(--text-primary);display:none}@media (min-width:640px){.practice-title{display:block}}.practice-timer{display:flex;align-items:center;gap:var(--space-2);padding:var(--space-2) var(--space-3);background:var(--bg-tertiary);border-radius:var(--radius-md);font-family:var(--font-mono);font-size:var(--text-sm);font-weight:600;color:var(--text-primary)}.practice-timer svg{width:16px;height:16px;color:var(--text-muted)}.practice-timer.warning{background:var(--warning-light);color:var(--warning)}.practice-timer.danger{background:var(--error-light);color:var(--error);animation:pulse 1s infinite}.practice-main{display:flex;flex:1;padding-top:var(--header-height)}.practice-navigator{display:none;position:fixed;top:var(--header-height);left:0;bottom:0;width:200px;background:var(--bg-primary);border-right:1px solid var(--border);padding:var(--space-4);overflow-y:auto}@media (min-width:992px){.practice-navigator{display:block}}.navigator-title{font-size:var(--text-sm);font-weight:600;color:var(--text-muted);margin-bottom:var(--space-4);text-transform:uppercase;letter-spacing:0.05em}.navigator-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:var(--space-2)}.navigator-item{width:100%;aspect-ratio:1;display:flex;align-items:center;justify-content:center;font-size:var(--text-sm);font-weight:500;background:var(--bg-tertiary);border:2px solid transparent;border-radius:var(--radius-sm);cursor:pointer;transition:all var(--transition-fast);color:var(--text-secondary)}.navigator-item:hover{background:var(--accent-light);border-color:var(--accent-primary)}.navigator-item.current{background:var(--accent-primary);color:var(--text-inverse);border-color:var(--accent-primary)}.navigator-item.answered{background:var(--success-light);border-color:var(--success);color:var(--success-dark)}.navigator-item.marked{background:var(--warning-light);border-color:var(--warning);color:var(--warning)}.navigator-item.answered.marked{background:var(--success-light);border-color:var(--warning)}.navigator-legend{margin-top:var(--space-6);padding-top:var(--space-4);border-top:1px solid var(--border)}.legend-item{display:flex;align-items:center;gap:var(--space-2);font-size:var(--text-xs);color:var(--text-muted);margin-bottom:var(--space-2)}.legend-dot{width:12px;height:12px;border-radius:var(--radius-sm);border:2px solid}.legend-dot.current{background:var(--accent-primary);border-color:var(--accent-primary)}.legend-dot.answered{background:var(--success-light);border-color:var(--success)}.legend-dot.marked{background:var(--warning-light);border-color:var(--warning)}.legend-dot.unanswered{background:var(--bg-tertiary);border-color:var(--border)}.practice-content{flex:1;padding:var(--space-4);max-width:100%;margin:0 auto}@media (min-width:768px){.practice-content{padding:var(--space-6)}}@media (min-width:992px){.practice-content{margin-left:200px;margin-right:260px;padding:var(--space-8)}}.question-card{background:var(--bg-primary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--space-6);margin-bottom:var(--space-4)}.question-header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:var(--space-4);padding-bottom:var(--space-4);border-bottom:1px solid var(--border)}.question-number{font-size:var(--text-lg);font-weight:600;color:var(--text-primary)}.question-meta{display:flex;align-items:center;gap:var(--space-3)}.question-marks{font-size:var(--text-sm);color:var(--text-muted);padding:var(--space-1) var(--space-3);background:var(--bg-tertiary);border-radius:var(--radius-full)}.question-type{font-size:var(--text-xs);font-weight:500;color:var(--accent-primary);text-transform:uppercase;letter-spacing:0.05em}.question-content{font-size:var(--text-base);line-height:var(--leading-relaxed);color:var(--text-primary);margin-bottom:var(--space-6)}.question-content p{margin-bottom:var(--space-4)}.question-content .math-inline{font-family:var(--font-mono)}.question-diagram{margin:var(--space-6)0;text-align:center}.question-diagram svg{max-width:100%;height:auto;max-height:300px}.options-list{display:flex;flex-direction:column;gap:var(--space-3)}.option-item{display:flex;align-items:flex-start;gap:var(--space-3);padding:var(--space-4);background:var(--bg-secondary);border:2px solid var(--border);border-radius:var(--radius-md);cursor:pointer;transition:all var(--transition-fast)}.option-item:hover{background:var(--bg-tertiary);border-color:var(--accent-primary)}.option-item.selected{background:var(--accent-light);border-color:var(--accent-primary)}.option-item.correct{background:var(--success-light);border-color:var(--success)}.option-item.incorrect{background:var(--error-light);border-color:var(--error)}.option-item.disabled{pointer-events:none;opacity:0.7}.option-radio{flex-shrink:0;width:24px;height:24px;border:2px solid var(--border);border-radius:50%;display:flex;align-items:center;justify-content:center;transition:all var(--transition-fast)}.option-item.selected .option-radio{border-color:var(--accent-primary);background:var(--accent-primary)}.option-item.selected .option-radio::after{content:"";width:8px;height:8px;background:white;border-radius:50%}.option-item.correct .option-radio{border-color:var(--success);background:var(--success)}.option-item.correct .option-radio::after{content:"";width:10px;height:10px;background:url(data:image/svg+xml,%3Csvg\ xmlns=\'http://www.w3.org/2000/svg\'\ viewBox=\'0\ 0\ 24\ 24\'\ fill=\'none\'\ stroke=\'white\'\ stroke-width=\'3\'%3E%3Cpolyline\ points=\'20\ 6\ 9\ 17\ 4\ 12\'%3E%3C/polyline%3E%3C/svg%3E)center/contain no-repeat}.option-item.incorrect .option-radio{border-color:var(--error);background:var(--error)}.option-item.incorrect .option-radio::after{content:"";width:10px;height:10px;background:url(data:image/svg+xml,%3Csvg\ xmlns=\'http://www.w3.org/2000/svg\'\ viewBox=\'0\ 0\ 24\ 24\'\ fill=\'none\'\ stroke=\'white\'\ stroke-width=\'3\'%3E%3Cline\ x1=\'18\'\ y1=\'6\'\ x2=\'6\'\ y2=\'18\'%3E%3C/line%3E%3Cline\ x1=\'6\'\ y1=\'6\'\ x2=\'18\'\ y2=\'18\'%3E%3C/line%3E%3C/svg%3E)center/contain no-repeat}.option-label{font-weight:600;color:var(--text-muted);min-width:24px}.option-text{flex:1;color:var(--text-primary)}.option-result{font-size:var(--text-xs);font-weight:500;padding:var(--space-1) var(--space-2);border-radius:var(--radius-sm)}.option-result.correct-answer{background:var(--success-light);color:var(--success-dark)}.option-result.your-answer{background:var(--error-light);color:var(--error)}.answer-input{width:100%;padding:var(--space-4);font-family:var(--font-sans);font-size:var(--text-base);border:2px solid var(--border);border-radius:var(--radius-md);background:var(--bg-secondary);color:var(--text-primary);resize:vertical;min-height:100px;transition:border-color var(--transition-fast)}.answer-input:focus{outline:none;border-color:var(--accent-primary)}.answer-input::placeholder{color:var(--text-muted)}.math-input-container{display:flex;flex-direction:column;gap:var(--space-3)}.quick-math-bar{display:flex;align-items:center;gap:var(--space-3);flex-wrap:wrap}.quick-math-label{font-size:var(--text-sm);color:var(--text-muted);white-space:nowrap}.quick-math-buttons{display:flex;flex-wrap:wrap;gap:var(--space-1)}.quick-btn{display:flex;align-items:center;justify-content:center;min-width:36px;height:36px;padding:0 var(--space-2);background:var(--bg-secondary);border:1px solid var(--border);border-radius:var(--radius-md);color:var(--text-primary);font-size:var(--text-base);cursor:pointer;transition:all var(--transition-fast)}.quick-btn:hover{background:var(--accent-light);border-color:var(--accent-primary);transform:translateY(-1px)}.quick-btn:active{transform:translateY(0)}.input-hint{display:flex;align-items:center;gap:var(--space-2);padding:var(--space-2) var(--space-3);background:var(--bg-tertiary);border-radius:var(--radius-md);font-size:var(--text-sm);color:var(--text-muted)}.input-hint svg{flex-shrink:0;color:var(--accent-primary)}.input-hint code{background:var(--bg-secondary);padding:2px 6px;border-radius:var(--radius-sm);font-size:var(--text-xs);color:var(--accent-primary)}.math-preview-container{background:linear-gradient(135deg,var(--bg-secondary),var(--bg-tertiary));border:1px solid var(--border);border-radius:var(--radius-md);padding:var(--space-3) var(--space-4)}.math-preview-label{display:flex;align-items:center;gap:var(--space-2);font-size:var(--text-xs);color:var(--text-muted);text-transform:uppercase;letter-spacing:0.05em;margin-bottom:var(--space-2)}.math-preview-label svg{color:var(--success)}.math-preview{min-height:32px;font-size:var(--text-lg);line-height:1.8;color:var(--text-primary);word-wrap:break-word}@media (max-width:640px){.quick-math-bar{flex-direction:column;align-items:flex-start}.quick-btn{min-width:32px;height:32px;font-size:var(--text-sm)}.input-hint{flex-wrap:wrap}.input-hint span{flex:1 1 100%;margin-top:var(--space-1)}}.case-study-box{background:var(--bg-tertiary);border-left:4px solid var(--accent-primary);border-radius:var(--radius-md);padding:var(--space-6);margin-bottom:var(--space-6)}.case-study-title{font-size:var(--text-lg);font-weight:600;color:var(--accent-primary);margin-bottom:var(--space-4)}.case-study-content{color:var(--text-secondary);line-height:var(--leading-relaxed)}.sub-question{margin-top:var(--space-6);padding-top:var(--space-6);border-top:1px solid var(--border)}.sub-question-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:var(--space-3)}.sub-question-number{font-weight:600;color:var(--text-primary)}.sub-question-marks{font-size:var(--text-sm);color:var(--text-muted)}.solution-box{background:var(--success-light);border:1px solid var(--success);border-radius:var(--radius-lg);padding:var(--space-6);margin-top:var(--space-6)}[data-theme="dark"] .solution-box{background:rgba(16,185,129,0.1)}.solution-header{display:flex;align-items:center;gap:var(--space-2);font-size:var(--text-lg);font-weight:600;color:var(--success-dark);margin-bottom:var(--space-4)}.solution-header svg{width:24px;height:24px}.solution-steps{list-style:none;counter-reset:step}.solution-step{position:relative;padding-left:var(--space-8);margin-bottom:var(--space-3);color:var(--text-secondary)}.solution-step::before{counter-increment:step;content:counter(step);position:absolute;left:0;width:24px;height:24px;background:var(--success);color:white;border-radius:50%;font-size:var(--text-xs);font-weight:600;display:flex;align-items:center;justify-content:center}.solution-answer{margin-top:var(--space-4);padding-top:var(--space-4);border-top:1px solid rgba(16,185,129,0.3);font-weight:600;color:var(--success-dark)}.question-actions{display:flex;flex-wrap:wrap;gap:var(--space-3);margin-top:var(--space-6);padding-top:var(--space-4);border-top:1px solid var(--border)}.question-actions-left{display:flex;gap:var(--space-3)}.question-actions-right{display:flex;gap:var(--space-3);margin-left:auto}.practice-progress{display:none;position:fixed;top:var(--header-height);right:0;bottom:0;width:260px;background:var(--bg-primary);border-left:1px solid var(--border);padding:var(--space-6);overflow-y:auto}@media (min-width:992px){.practice-progress{display:block}}.progress-section{margin-bottom:var(--space-6)}.progress-title{font-size:var(--text-sm);font-weight:600;color:var(--text-muted);margin-bottom:var(--space-3);text-transform:uppercase;letter-spacing:0.05em}.progress-stat{text-align:center;padding:var(--space-4);background:var(--bg-secondary);border-radius:var(--radius-md)}.progress-stat-value{font-size:var(--text-3xl);font-weight:700;color:var(--accent-primary)}.progress-stat-label{font-size:var(--text-sm);color:var(--text-muted)}.progress-bar-container{margin-top:var(--space-4)}.progress-bar{height:8px;background:var(--bg-tertiary);border-radius:var(--radius-full);overflow:hidden}.progress-fill{height:100%;background:var(--accent-primary);border-radius:var(--radius-full);transition:width var(--transition-slow)}.progress-breakdown{display:flex;flex-direction:column;gap:var(--space-2);margin-top:var(--space-4)}.progress-breakdown-item{display:flex;justify-content:space-between;font-size:var(--text-sm);color:var(--text-secondary)}.progress-breakdown-value{font-weight:600}.mobile-navigator{position:fixed;bottom:0;left:0;right:0;background:var(--bg-primary);border-radius:var(--radius-xl) var(--radius-xl)0 0;box-shadow:var(--shadow-xl);transform:translateY(100%);transition:transform var(--transition-normal);z-index:110;max-height:70vh;overflow:hidden}.mobile-navigator.open{transform:translateY(0)}@media (min-width:992px){.mobile-navigator{display:none}}.mobile-navigator-header{display:flex;align-items:center;justify-content:space-between;padding:var(--space-4);border-bottom:1px solid var(--border)}.mobile-navigator-title{font-weight:600;color:var(--text-primary)}.mobile-navigator-body{padding:var(--space-4);overflow-y:auto;max-height:calc(70vh - 60px)}.mobile-navigator-grid{display:grid;grid-template-columns:repeat(6,1fr);gap:var(--space-2)}.mobile-navigator-footer{padding:var(--space-4);border-top:1px solid var(--border)}.mobile-nav-toggle{position:fixed;bottom:var(--space-4);right:var(--space-4);width:56px;height:56px;background:var(--accent-primary);color:white;border:none;border-radius:50%;box-shadow:var(--shadow-lg);display:flex;align-items:center;justify-content:center;cursor:pointer;z-index:100}.mobile-nav-toggle svg{width:24px;height:24px}@media (min-width:992px){.mobile-nav-toggle{display:none}}.mobile-submit-btn{position:fixed;bottom:var(--space-4);left:var(--space-4);display:flex;align-items:center;gap:var(--space-2);padding:var(--space-3) var(--space-4);background:var(--success);color:white;border:none;border-radius:var(--radius-lg);font-size:var(--text-sm);font-weight:600;box-shadow:var(--shadow-lg);cursor:pointer;z-index:100;transition:background 0.2s,transform 0.2s}.mobile-submit-btn:hover{background:var(--success-dark);transform:scale(1.02)}.mobile-submit-btn:active{transform:scale(0.98)}.mobile-submit-btn svg{width:18px;height:18px}@media (min-width:992px){.mobile-submit-btn{display:none}}.results-container{max-width:600px;margin:0 auto;padding:var(--space-8) var(--space-4)}.results-header{text-align:center;margin-bottom:var(--space-8)}.results-title{font-size:var(--text-3xl);font-weight:700;color:var(--text-primary);margin-bottom:var(--space-4)}.results-score-circle{width:160px;height:160px;margin:0 auto var(--space-6);background:var(--bg-hero);border-radius:50%;display:flex;flex-direction:column;align-items:center;justify-content:center;color:white}.results-score-value{font-size:var(--text-4xl);font-weight:700}.results-score-label{font-size:var(--text-sm);opacity:0.9}.results-breakdown{background:var(--bg-primary);border:1px solid var(--border);border-radius:var(--radius-lg);padding:var(--space-6);margin-bottom:var(--space-6)}.results-breakdown-title{font-size:var(--text-lg);font-weight:600;color:var(--text-primary);margin-bottom:var(--space-4)}.results-breakdown-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:var(--space-4);text-align:center}.results-breakdown-item{padding:var(--space-4);background:var(--bg-secondary);border-radius:var(--radius-md)}.results-breakdown-value{font-size:var(--text-2xl);font-weight:700}.results-breakdown-value.correct{color:var(--success)}.results-breakdown-value.incorrect{color:var(--error)}.results-breakdown-value.unattempted{color:var(--text-muted)}.results-breakdown-label{font-size:var(--text-sm);color:var(--text-muted)}.results-actions{display:flex;flex-direction:column;gap:var(--space-3)}@media (min-width:480px){.results-actions{flex-direction:row;justify-content:center}}.loading-spinner{width:40px;height:40px;border:3px solid var(--border);border-top-color:var(--accent-primary);border-radius:50%;animation:spin 0.8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.loading-overlay{position:fixed;inset:0;background:rgba(255,255,255,0.9);display:flex;align-items:center;justify-content:center;z-index:200}[data-theme="dark"] .loading-overlay{background:rgba(15,23,42,0.9)}.ms-workspace .container{max-width:100%;margin:0;padding:0}.ms-workspace .container.main-content{padding:0}.ms-workspace .grid.layout-grid{display:block}.ms-workspace .left-sidebar-col,.ms-workspace .right-sidebar-col{display:none}.ms-workspace .breadcrumb{display:none}.ms-workspace .practice-col{max-width:780px;margin:0 auto}.ms-workspace #topic-title{display:none}.ms-workspace .card>header{margin-bottom:0.75rem}.ms-workspace .visualizer-box{padding:1.1rem 1.25rem}.ms-workspace .visualizer-box .math-visualizer{font-size:1rem}.ms-workspace .visualizer-box .step-intro{font-size:1.15rem!important;line-height:1.45}.ms-workspace .visualizer-box .problem{font-size:1.25rem}.ms-workspace .visualizer-box .step{font-size:0.98rem}.ms-workspace .visualizer-box .result{font-size:1.2rem}.ms-workspace .question-display{font-size:clamp(1.3rem,2.2vw,1.8rem);margin:1rem 0;line-height:1.35}.ms-workspace .stat-value{font-size:1.45rem}.ms-workspace .game-input{font-size:1.4rem}.ms-workspace .game-header{gap:1rem}.ms-workspace .learn-section h3{font-size:1.05rem}.ms-workspace{--bg-primary:var(--ms-panel-bg);--bg-secondary:var(--ms-panel-bg-soft);--bg-tertiary:var(--ms-panel-bg-soft);--bg-hover:var(--ms-panel-bg-soft);--text-primary:var(--ms-ink);--text-secondary:var(--ms-ink-soft);--text-muted:var(--ms-muted);--border:var(--ms-line);--border-dark:var(--ms-line-strong);--accent-primary:var(--ms-accent);--accent-dark:var(--ms-accent-hover);--accent-light:var(--ms-accent-soft)}.ms-workspace .learn-details>summary{cursor:pointer;font-weight:700;font-size:1.05rem;color:var(--ms-ink);list-style:none;display:flex;align-items:center;gap:0.5rem}.ms-workspace .learn-details>summary::-webkit-details-marker{display:none}.ms-workspace .learn-details>summary::before{content:"▸";color:var(--ms-accent);transition:transform 0.18s var(--ms-ease,ease)}.ms-workspace .learn-details[open]>summary::before{transform:rotate(90deg)}.ms-workspace .learn-details[open]>summary{margin-bottom:0.85rem}.ms-workspace .game-header{flex-wrap:wrap;row-gap:0.75rem}.ms-workspace .game-header .stat-box{flex:1 1 auto;min-width:68px}.ms-workspace .game-controls{display:flex;flex-wrap:wrap;gap:0.5rem;align-items:center}.ms-workspace .share-menu{display:flex;flex-wrap:wrap;gap:0.4rem;width:100%;margin-top:0.4rem}.ms-workspace .share-menu[hidden]{display:none}.ms-workspace .share-chip{font-size:0.8rem;font-weight:600;padding:0.32rem 0.7rem;border-radius:999px;border:1px solid var(--ms-line-strong);background:var(--ms-panel-bg-soft);color:var(--ms-ink);text-decoration:none;cursor:pointer;line-height:1.2}.ms-workspace .share-chip:hover{border-color:var(--ms-accent);color:var(--ms-accent)}.ms-workspace .btn{display:inline-flex;align-items:center;justify-content:center;gap:0.4rem;padding:0.6rem 1.15rem;border-radius:var(--ms-radius-pill,999px);font-family:var(--ms-font-sans,"Inter",sans-serif);font-weight:600;font-size:0.92rem;line-height:1;border:1px solid transparent;cursor:pointer;text-decoration:none;white-space:nowrap;-webkit-appearance:none;appearance:none;transition:transform .15s var(--ms-ease,ease),box-shadow .15s,background .15s,border-color .15s,color .15s,filter .15s}.ms-workspace .btn:focus-visible{outline:none;box-shadow:var(--ms-ring,0 0 0 3px rgba(21,128,61,.3))}.ms-workspace .btn:active{transform:translateY(1px)}.ms-workspace .btn:disabled{opacity:.55;cursor:not-allowed;transform:none;box-shadow:none;filter:none}.ms-workspace .btn-primary{background:linear-gradient(135deg,var(--ms-cta-start,#15803d),var(--ms-cta-end,#22c55e));color:#fff;box-shadow:0 2px 8px var(--ms-cta-shadow,rgba(21,128,61,.22))}.ms-workspace .btn-primary:hover:not(:disabled){filter:brightness(1.05);transform:translateY(-1px);box-shadow:0 6px 16px var(--ms-cta-shadow,rgba(21,128,61,.32))}.ms-workspace .btn-secondary{background:var(--ms-panel-bg,#fff);color:var(--ms-ink-soft,#44403c);border-color:var(--ms-line-strong,rgba(28,25,23,.14))}.ms-workspace .btn-secondary:hover:not(:disabled){border-color:var(--ms-accent,#15803d);color:var(--ms-accent,#15803d);background:var(--ms-accent-softer,rgba(21,128,61,.04));transform:translateY(-1px)}.ms-workspace .btn-sm{padding:0.42rem 0.85rem;font-size:0.82rem}.ms-workspace .btn-game{padding:0.72rem 1.7rem;font-size:1.02rem;border-radius:var(--ms-radius,14px)}.ms-workspace .input-group{gap:0.5rem;max-width:440px}.ms-workspace .game-input{border:2px solid var(--ms-line-strong,rgba(28,25,23,.14));border-radius:var(--ms-radius,14px);background:var(--ms-panel-bg,#fff);color:var(--ms-ink,#1c1917);font-weight:700;transition:border-color .15s,box-shadow .15s}.ms-workspace .game-input:focus{border-color:var(--ms-accent,#15803d);box-shadow:var(--ms-ring,0 0 0 3px rgba(21,128,61,.22));outline:none}