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h1{margin-bottom:var(--space-lg)}.hero-subtitle{font-size:clamp(1rem,2vw,1.25rem);color:var(--color-gray-600);line-height:1.7;margin-bottom:var(--space-xl);max-width:600px;margin-left:auto;margin-right:auto}.hero-actions{display:flex;gap:var(--space-md);justify-content:center;flex-wrap:wrap}.hero-stats{display:flex;justify-content:center;gap:4vw;margin-top:6vh;flex-wrap:wrap}.stat{text-align:center}.stat-number{display:block;font-size:var(--font-size-2xl);font-weight:700;color:var(--color-primary)}.stat-label{display:block;font-size:var(--font-size-sm);color:var(--color-gray-500);margin-top:var(--space-xs)}.features{background:var(--color-white)}.section-header h2{margin-bottom:var(--space-sm)}.section-header .text-muted{max-width:500px;margin:0 auto}.feature-card{text-align:center;padding:var(--space-2xl)}.feature-icon{font-size:2.5rem;margin-bottom:var(--space-lg)}.feature-title{font-size:var(--font-size-xl);margin-bottom:var(--space-sm)}.feature-description{line-height:1.6}.topics{background:var(--color-gray-50)}.topics-grid{display:flex;flex-wrap:wrap;gap:var(--space-md);justify-content:center;max-width:800px;margin:0 auto}.topic-item{display:flex;align-items:center;justify-content:space-between;background:var(--color-white);padding:var(--space-md) var(--space-lg);border-radius:var(--radius-lg);border:1px solid var(--color-gray-200);min-width:280px;flex:1 1 calc(50% - var(--space-md))}.topic-name{font-weight:500;color:var(--color-gray-800)}.topic-count{font-size:var(--font-size-xs)}.cta{background:var(--color-primary);color:var(--color-white)}.cta h2{color:var(--color-white)}.cta .text-muted{color:#fffc}.cta .btn-primary{background:var(--color-white);color:var(--color-primary)}.cta .btn-primary:hover{background:var(--color-gray-100)}@media(max-width:768px){.hero{min-height:80vh;padding:4vh 5vw}.hero-stats{gap:2vw}.stat-number{font-size:var(--font-size-xl)}.topic-item{flex:1 1 100%}}.practice-page{min-height:100vh;padding:4vh 4vw;background:var(--color-gray-50);width:100%}.practice-header{text-align:center;margin-bottom:var(--space-xl)}.practice-header h1{margin-bottom:var(--space-sm)}.loading-state{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:10vh 0;gap:var(--space-md)}.loading-state .spinner{width:40px;height:40px}.mode-selector{display:flex;gap:var(--space-md);margin-bottom:var(--space-xl)}.mode-btn{flex:1;display:flex;align-items:center;gap:var(--space-md);padding:var(--space-lg);background:var(--color-white);border:2px solid var(--color-gray-200);border-radius:var(--radius-lg);cursor:pointer;transition:all var(--transition-base);text-align:left}.mode-btn:hover{border-color:var(--color-primary-light)}.mode-btn.active{border-color:var(--color-primary);background:var(--color-primary-bg)}.mode-icon{font-size:1.5rem}.mode-btn div{display:flex;flex-direction:column}.mode-btn strong{color:var(--color-gray-900)}.mode-btn .text-sm{margin-top:var(--space-xs)}.courses-list{display:flex;flex-direction:column;gap:var(--space-md)}.course-card{background:var(--color-white);border:1px solid var(--color-gray-200);border-radius:var(--radius-lg);overflow:hidden}.course-header{display:flex;align-items:center;gap:var(--space-md);padding:var(--space-lg);cursor:pointer;transition:background var(--transition-fast)}.course-header:hover{background:var(--color-gray-50)}.course-header h3{flex:1;font-size:var(--font-size-lg);margin:0}.expand-icon{color:var(--color-gray-400);font-size:var(--font-size-sm)}.course-content{padding:0 var(--space-lg) var(--space-lg);border-top:1px solid var(--color-gray-100)}.course-actions{display:flex;gap:var(--space-sm);margin-bottom:var(--space-md);padding-top:var(--space-md)}.topics-list{display:flex;flex-direction:column;gap:var(--space-sm)}.topic-checkbox{display:flex;align-items:center;gap:var(--space-md);padding:var(--space-sm) var(--space-md);border-radius:var(--radius-md);cursor:pointer;transition:background var(--transition-fast)}.topic-checkbox:hover{background:var(--color-gray-50)}.topic-checkbox input[type=checkbox]{width:18px;height:18px;accent-color:var(--color-primary)}.topic-title{color:var(--color-gray-700)}.practice-footer{display:flex;align-items:center;justify-content:space-between;margin-top:var(--space-xl);padding:var(--space-lg);background:var(--color-white);border-radius:var(--radius-lg);box-shadow:var(--shadow-md);position:sticky;bottom:var(--space-md)}.selected-count{color:var(--color-gray-600)}.selected-count strong{color:var(--color-primary);font-size:var(--font-size-xl)}.question-page{min-height:100vh;padding:4vh 4vw;width:100%}.question-container{max-width:900px;margin:0 auto;width:100%}.question-progress{display:flex;align-items:center;justify-content:space-between;margin-bottom:var(--space-lg)}.question-level{font-weight:700;font-size:var(--font-size-lg);color:var(--color-gray-800)}.question-progress-right{display:flex;align-items:center;gap:var(--space-md)}.score-tracker{font-size:var(--font-size-sm);font-weight:600;color:var(--color-gray-600)}.score-tracker.score-perfect{color:var(--color-success, #10b981)}.question-timer{font-size:var(--font-size-sm);color:var(--color-gray-500)}.completion-score{font-size:3.5rem;font-weight:800;color:var(--color-primary, #2563eb);margin-bottom:var(--space-md)}.completion-message{color:var(--color-gray-700);margin-bottom:var(--space-xl)}.completion-actions{display:flex;flex-direction:column;gap:var(--space-md);align-items:center;max-width:300px;margin:0 auto}.completion-actions .btn{width:100%;text-decoration:none;text-align:center}.question-card{background:var(--color-white);border-radius:var(--radius-xl);padding:var(--space-2xl);box-shadow:var(--shadow-md)}.question-image{max-width:100%;border-radius:var(--radius-md);margin-bottom:var(--space-lg)}.question-text{font-size:var(--font-size-lg);line-height:1.7;color:var(--color-gray-900);margin-bottom:var(--space-xl)}.choices-list{display:flex;flex-direction:column;gap:var(--space-md);margin-bottom:var(--space-xl)}.question-actions{display:flex;gap:var(--space-md);justify-content:flex-end}.feedback-section{margin-top:var(--space-xl);padding:var(--space-lg);border-radius:var(--radius-lg)}.feedback-section.correct{background:var(--color-success-bg);border:1px solid var(--color-success)}.feedback-section.incorrect{background:var(--color-error-bg);border:1px solid var(--color-error)}.feedback-header{display:flex;align-items:center;gap:var(--space-sm);font-weight:600;margin-bottom:var(--space-md)}.explanation-text{line-height:1.7;color:var(--color-gray-700)}.explanation-steps{display:flex;flex-direction:column;gap:var(--space-lg);margin-top:var(--space-lg);padding-top:var(--space-lg);border-top:1px solid var(--color-gray-200)}.explanation-step{background:var(--color-white);border:1px solid var(--color-gray-200);border-radius:var(--radius-lg);padding:var(--space-lg)}.step-number{display:inline-block;background:var(--color-primary);color:var(--color-white);font-weight:600;font-size:var(--font-size-sm);padding:var(--space-xs) var(--space-md);border-radius:var(--radius-md);margin-bottom:var(--space-md)}.explanation-step-image{max-width:100%;border-radius:var(--radius-md);display:block}.step-caption{margin-top:var(--space-md);color:var(--color-gray-600);font-size:var(--font-size-sm);line-height:1.5}.explain-btn{margin-top:var(--space-lg);width:100%}.guest-banner{display:flex;align-items:center;gap:var(--space-md);padding:var(--space-md) var(--space-lg);background:linear-gradient(135deg,var(--color-primary-light),var(--color-primary));color:var(--color-white);border-radius:var(--radius-lg);margin-bottom:var(--space-xl)}.guest-banner-icon{font-size:2rem}.guest-banner-text{display:flex;flex-direction:column;gap:var(--space-xs)}.guest-banner-text strong{font-size:var(--font-size-lg)}.guest-banner-text span{font-size:var(--font-size-sm);opacity:.9}.guest-banner-text a{color:var(--color-white);text-decoration:underline;font-weight:600}.guest-limit-banner{display:flex;align-items:center;justify-content:center;gap:var(--space-sm);padding:var(--space-sm) var(--space-md);background:var(--color-warning-light);color:var(--color-warning-dark);border-radius:var(--radius-md);margin-bottom:var(--space-md);font-size:var(--font-size-sm);font-weight:500}.guest-limit-banner .limit-count{font-weight:700}.modal-overlay{position:fixed;inset:0;background:#0009;display:flex;align-items:center;justify-content:center;z-index:1000;animation:fadeIn .2s ease-out}.modal-content{background:var(--color-white);padding:var(--space-xl);border-radius:var(--radius-xl);max-width:400px;width:90%;text-align:center;animation:slideUp .3s ease-out}.modal-content h2{margin-bottom:var(--space-md);color:var(--color-gray-800)}.modal-content p{margin-bottom:var(--space-lg);color:var(--color-gray-600);line-height:1.6}.modal-subtext{font-size:var(--font-size-sm);color:var(--color-gray-500);margin-bottom:var(--space-lg)}.modal-actions{display:flex;gap:var(--space-md);margin-bottom:var(--space-md)}.modal-actions .btn{flex:1}.modal-close{background:none;border:none;color:var(--color-gray-500);font-size:var(--font-size-sm);cursor:pointer;padding:var(--space-sm)}.modal-close:hover{color:var(--color-gray-700);text-decoration:underline}@keyframes fadeIn{0%{opacity:0}to{opacity:1}}@keyframes slideUp{0%{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}@media(max-width:768px){.mode-selector{flex-direction:column}.practice-footer{flex-direction:column;gap:var(--space-md);text-align:center}.practice-footer .btn{width:100%}.question-card{padding:var(--space-lg)}.guest-banner{flex-direction:column;text-align:center}.modal-actions{flex-direction:column}}.confetti-canvas{position:fixed!important;top:0!important;left:0!important;width:100%!important;height:100%!important;pointer-events:none!important;z-index:1500!important;background:transparent!important;border:none!important;outline:none!important}.google-login-btn{width:100%;display:flex;align-items:center;justify-content:center;gap:var(--space-sm);padding:var(--space-md) var(--space-lg);background:var(--color-white);border:2px solid var(--color-gray-200);border-radius:var(--radius-lg);font-size:var(--font-size-base);font-weight:500;color:var(--color-gray-700);cursor:pointer;transition:all var(--transition-base)}.google-login-btn:hover:not(:disabled){border-color:var(--color-gray-300);background:var(--color-gray-50);box-shadow:var(--shadow-sm)}.google-login-btn:disabled{opacity:.7;cursor:not-allowed}.google-icon{width:18px;height:18px;flex-shrink:0}.auth-divider{display:flex;align-items:center;gap:var(--space-md);margin:var(--space-lg) 0}.auth-divider:before,.auth-divider:after{content:"";flex:1;height:1px;background:var(--color-gray-200)}.auth-divider span{color:var(--color-gray-400);font-size:var(--font-size-sm);text-transform:uppercase;letter-spacing:.5px}.auth-page{min-height:100vh;display:flex;align-items:center;justify-content:center;padding:5vh 4vw;background:var(--color-gray-50);width:100%}.auth-container{width:100%;max-width:440px;background:var(--color-white);padding:var(--space-2xl);border-radius:var(--radius-xl);box-shadow:var(--shadow-lg)}@media(max-width:480px){.input-row{flex-direction:column;gap:0}}.auth-header{text-align:center;margin-bottom:var(--space-xl)}.auth-header h1{font-size:var(--font-size-2xl);margin-bottom:var(--space-sm)}.auth-form{margin-bottom:var(--space-lg)}.input-row{display:flex;gap:var(--space-md)}.input-row .input-group{flex:1}.auth-footer{text-align:center;padding-top:var(--space-lg);border-top:1px solid var(--color-gray-200)}.auth-footer p{color:var(--color-gray-600);font-size:var(--font-size-sm)}.profile-page{min-height:100vh;display:flex;align-items:flex-start;justify-content:center;padding:8vh 4vw;background:var(--color-gray-50);width:100%}.profile-container{width:100%;max-width:500px;background:var(--color-white);padding:var(--space-2xl);border-radius:var(--radius-xl);box-shadow:var(--shadow-md)}.profile-header{text-align:center;margin-bottom:var(--space-xl)}.profile-avatar{width:80px;height:80px;border-radius:50%;background:var(--color-primary);color:var(--color-white);display:flex;align-items:center;justify-content:center;font-size:var(--font-size-3xl);font-weight:600;margin:0 auto var(--space-md)}.profile-header h1{font-size:var(--font-size-2xl);margin-bottom:var(--space-xs)}.tier-badge{display:inline-block;padding:var(--space-xs) var(--space-md);border-radius:var(--radius-md);font-size:var(--font-size-sm);font-weight:600;margin-top:var(--space-sm)}.tier-free{background:var(--color-gray-100);color:var(--color-gray-700)}.tier-standard{background:var(--color-primary-bg);color:var(--color-primary)}.tier-premium{background:#fef3c7;color:#b45309}.loading-container{display:flex;justify-content:center;padding:var(--space-2xl)}.profile-stats{display:flex;flex-direction:column;gap:var(--space-lg);margin-bottom:var(--space-xl)}.stat-card{background:var(--color-gray-50);padding:var(--space-lg);border-radius:var(--radius-lg);text-align:center}.stat-card h3{font-size:var(--font-size-sm);color:var(--color-gray-600);font-weight:500;margin-bottom:var(--space-sm)}.stat-value{font-size:var(--font-size-3xl);font-weight:700;color:var(--color-gray-900)}.usage-display{display:flex;align-items:baseline;justify-content:center;gap:var(--space-xs)}.stat-limit{font-size:var(--font-size-lg);color:var(--color-gray-500)}.usage-bar{width:100%;height:8px;background:var(--color-gray-200);border-radius:var(--radius-sm);margin:var(--space-md) 0;overflow:hidden}.usage-fill{height:100%;background:var(--color-primary);border-radius:var(--radius-sm);transition:width .3s ease}.upgrade-prompt{background:var(--color-primary-bg);padding:var(--space-lg);border-radius:var(--radius-lg);text-align:center;border:1px solid var(--color-primary-light)}.upgrade-prompt p{color:var(--color-gray-700);margin-bottom:var(--space-md)}.profile-actions{display:flex;gap:var(--space-md)}.profile-actions .btn{flex:1}@media(max-width:480px){.profile-actions{flex-direction:column}}.pricing-page{min-height:100vh;padding:8vh 4vw;background:var(--color-gray-50);width:100%}.pricing-header{text-align:center;max-width:600px;margin:0 auto var(--space-2xl)}.pricing-header h1{font-size:var(--font-size-3xl);margin-bottom:var(--space-sm)}.billing-toggle{display:inline-flex;background:var(--color-gray-100);padding:4px;border-radius:var(--radius-lg);margin-top:var(--space-lg)}.toggle-btn{padding:var(--space-sm) var(--space-lg);border:none;background:transparent;border-radius:var(--radius-md);font-size:var(--font-size-sm);font-weight:500;cursor:pointer;color:var(--color-gray-600);transition:all var(--transition-base);display:flex;align-items:center;gap:var(--space-sm)}.toggle-btn.active{background:var(--color-white);color:var(--color-gray-900);box-shadow:var(--shadow-sm)}.save-badge{background:var(--color-success);color:var(--color-white);font-size:var(--font-size-xs);padding:2px 6px;border-radius:var(--radius-sm)}.pricing-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(280px,1fr));gap:var(--space-lg);max-width:1000px;margin:0 auto}.pricing-card{background:var(--color-white);border:2px solid var(--color-gray-200);border-radius:var(--radius-xl);padding:var(--space-xl);text-align:center;position:relative;transition:all var(--transition-base)}.pricing-card:hover{box-shadow:var(--shadow-md)}.pricing-card.popular{border-color:var(--color-primary)}.pricing-card.current{border-color:var(--color-success)}.popular-tag,.current-tag{position:absolute;top:-12px;left:50%;transform:translate(-50%);padding:var(--space-xs) var(--space-md);border-radius:var(--radius-md);font-size:var(--font-size-xs);font-weight:600}.popular-tag{background:var(--color-primary);color:var(--color-white)}.current-tag{background:var(--color-success);color:var(--color-white)}.pricing-card h2{font-size:var(--font-size-xl);margin-bottom:var(--space-md);margin-top:var(--space-sm)}.price{display:flex;align-items:baseline;justify-content:center;margin-bottom:var(--space-sm)}.price .currency{font-size:var(--font-size-xl);color:var(--color-gray-600)}.price .amount{font-size:var(--font-size-4xl);font-weight:700;color:var(--color-gray-900)}.price .period{font-size:var(--font-size-base);color:var(--color-gray-500);margin-left:var(--space-xs)}.yearly-note{color:var(--color-success);font-size:var(--font-size-sm);margin-bottom:var(--space-md)}.features{text-align:left;margin:var(--space-xl) 0;padding:var(--space-lg) 0;border-top:1px solid var(--color-gray-200);border-bottom:1px solid var(--color-gray-200)}.feature-row{display:flex;align-items:center;gap:var(--space-sm);padding:var(--space-sm) 0;font-size:var(--font-size-sm);color:var(--color-gray-700)}.feature-check{color:var(--color-success);font-weight:600}.pricing-card .btn{width:100%}.pricing-footer{text-align:center;margin-top:var(--space-2xl);color:var(--color-gray-600)}.pricing-footer p{margin-bottom:var(--space-sm)}.loading-container{display:flex;justify-content:center;align-items:center;min-height:50vh}@media(max-width:768px){.pricing-grid{grid-template-columns:1fr;max-width:400px}}.checkout-page{width:100%;min-height:80vh;display:flex;align-items:center;justify-content:center;padding:2rem}.checkout-container{max-width:480px;width:100%}.checkout-container h1{margin-bottom:1.5rem;font-size:1.5rem}.back-link{background:none;border:none;color:var(--color-primary, #4f46e5);cursor:pointer;padding:0;margin-bottom:1rem;font-size:.9rem;display:inline-block}.back-link:hover{text-decoration:underline}.checkout-form{background:var(--color-surface, #fff);border:1px solid var(--color-border, #e5e7eb);border-radius:12px;padding:2rem;box-shadow:0 4px 12px #0000000f}.plan-summary{text-align:center;padding-bottom:1.5rem;border-bottom:1px solid var(--color-border, #e5e7eb);margin-bottom:1.5rem}.plan-summary h2{margin:0 0 .5rem;font-size:1.25rem}.plan-price .amount{font-size:2rem;font-weight:700}.plan-price .period{color:var(--color-text-muted, #6b7280);font-size:1rem}.discount-applied{color:#16a34a;font-size:.85rem;margin-top:.5rem}.form-section{margin-bottom:1.25rem}.form-section label{display:block;font-size:.85rem;font-weight:600;margin-bottom:.5rem;color:var(--color-text, #1f2937)}.card-element-wrapper{border:1px solid var(--color-border, #d1d5db);border-radius:8px;padding:12px;background:#fff;transition:border-color .2s}.card-element-wrapper:focus-within{border-color:var(--color-primary, #4f46e5);box-shadow:0 0 0 2px #4f46e526}.discount-section .discount-row{display:flex;gap:.5rem}.discount-section input{flex:1;border:1px solid var(--color-border, #d1d5db);border-radius:8px;padding:10px 12px;font-size:.9rem;outline:none;transition:border-color .2s}.discount-section input:focus{border-color:var(--color-primary, #4f46e5)}.btn-validate{padding:10px 16px;border:1px solid var(--color-border, #d1d5db);border-radius:8px;background:var(--color-surface, #f9fafb);cursor:pointer;font-size:.85rem;font-weight:500;white-space:nowrap;transition:background .2s}.btn-validate:hover:not(:disabled){background:var(--color-border, #e5e7eb)}.btn-validate:disabled{opacity:.5;cursor:not-allowed}.checkout-error{background:#fef2f2;color:#dc2626;padding:10px 14px;border-radius:8px;font-size:.85rem;margin-bottom:1rem;border:1px solid #fecaca}.btn-subscribe{width:100%;padding:14px;background:var(--color-primary, #4f46e5);color:#fff;border:none;border-radius:8px;font-size:1rem;font-weight:600;cursor:pointer;transition:background .2s,transform .1s}.btn-subscribe:hover:not(:disabled){background:var(--color-primary-hover, #4338ca);transform:translateY(-1px)}.btn-subscribe:disabled{opacity:.6;cursor:not-allowed;transform:none}.checkout-terms{text-align:center;font-size:.75rem;color:var(--color-text-muted, #9ca3af);margin-top:1rem}.trial-notice{background:#ecfdf5;border:2px solid #10b981;border-radius:8px;padding:14px;margin-bottom:1.5rem;text-align:center}.trial-title{font-size:1rem;font-weight:700;color:#065f46;margin-bottom:4px}.trial-subtitle{font-size:.8rem;color:#047857}.checkout-success{background:var(--color-surface, #fff);border:1px solid var(--color-border, #e5e7eb);border-radius:12px;padding:3rem 2rem;text-align:center;box-shadow:0 4px 12px #0000000f}.success-icon{width:56px;height:56px;background:#10b981;color:#fff;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:1.5rem;font-weight:700;margin:0 auto 1rem}.checkout-success h2{margin:0 0 .5rem}.checkout-success p{color:var(--color-text-muted, #6b7280);font-size:.9rem}.redirect-note{margin-top:1rem;font-size:.8rem;color:var(--color-text-muted, #9ca3af)}.checkout-error-page{text-align:center;padding:3rem 0}.checkout-error-page p{color:var(--color-text-muted, #6b7280);margin:1rem 0 2rem}.loading-container{display:flex;flex-direction:column;justify-content:center;align-items:center;min-height:200px;gap:1rem}.loading-container p{color:var(--color-text-muted, #6b7280);font-size:.9rem}.spinner{width:32px;height:32px;border:3px solid var(--color-border, #e5e7eb);border-top-color:var(--color-primary, #4f46e5);border-radius:50%;animation:spin .6s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.go-page{width:100%;min-height:80vh;display:flex;align-items:center;justify-content:center;padding:0 5vw;background:var(--color-gray-50, #f9fafb)}.go-content{max-width:560px;text-align:center}.go-content h1{font-size:clamp(2rem,5vw,3rem);font-weight:700;margin-bottom:var(--space-md, 1rem)}.go-subtitle{font-size:clamp(1rem,2vw,1.15rem);color:var(--color-gray-600, #6b7280);line-height:1.6;margin-bottom:var(--space-xl, 2rem)}.go-loading{font-size:1.1rem;color:var(--color-gray-500, #9ca3af)}.go-error{margin-top:var(--space-lg, 1.5rem);background:#fef2f2;border:1px solid #fecaca;border-radius:var(--radius-lg, 12px);padding:var(--space-lg, 1.5rem)}.go-error p{color:#dc2626;margin-bottom:var(--space-md, 1rem)}.go-signup-btn{display:inline-block;text-decoration:none}.go-features{display:flex;gap:var(--space-lg, 1.5rem);margin-top:6vh;flex-wrap:wrap;justify-content:center}.go-feature{flex:1 1 140px;text-align:center}.go-feature strong{display:block;font-size:var(--font-size-base, 1rem);margin-bottom:4px}.go-feature span{font-size:var(--font-size-sm, .875rem);color:var(--color-gray-500, #9ca3af)}