:root{color-scheme:light;--font-sans: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;--color-bg: #f8fbff;--color-bg-accent: #edf6ff;--color-surface: rgba(255, 255, 255, .92);--color-surface-strong: #ffffff;--color-text: #243447;--color-heading: #142238;--color-muted: #6b7c93;--color-border: #d9e8f6;--color-primary: #3f8fd2;--color-primary-strong: #256ba6;--color-primary-soft: #e9f4ff;--color-accent: #75bce8;--color-accent-soft: #f0f9ff;--color-success: #4b9f7a;--color-success-soft: #edf9f3;--color-danger: #c66f7b;--color-danger-soft: #fff4f6;--color-warning: #b9893d;--color-warning-soft: #fff8e8;--color-status-text: #ffffff;--space-1: .25rem;--space-2: .5rem;--space-3: .75rem;--space-4: 1rem;--space-5: 1.5rem;--space-6: 2rem;--space-7: 3rem;--radius-sm: .625rem;--radius-md: .875rem;--radius-lg: 1.25rem;--radius-xl: 1.75rem;--shadow-sm: 0 8px 24px rgba(50, 92, 135, .08);--shadow-md: 0 18px 45px rgba(63, 143, 210, .14);--transition: .16s 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.28)}}:root[data-theme=dark]{color-scheme:dark;--color-bg: #0f1b2b;--color-bg-accent: #152842;--color-surface: rgba(20, 35, 55, .9);--color-surface-strong: #182a42;--color-text: #dce8f5;--color-heading: #f3f8ff;--color-muted: #9fb2c8;--color-border: #2c4766;--color-primary: #8fc7f0;--color-primary-strong: #b9ddf7;--color-primary-soft: rgba(143, 199, 240, .14);--color-accent: #b7ddf7;--color-accent-soft: rgba(183, 221, 247, .12);--color-success: #8fd3b0;--color-success-soft: rgba(143, 211, 176, .13);--color-danger: #e4a0aa;--color-danger-soft: rgba(228, 160, 170, .14);--color-warning: #e5c882;--color-warning-soft: rgba(229, 200, 130, .14);--color-status-text: #0f1b2b;--shadow-sm: 0 8px 24px rgba(0, 0, 0, .2);--shadow-md: 0 18px 48px rgba(0, 0, 0, .28)}*{box-sizing:border-box}html{min-height:100%;background:radial-gradient(circle at top left,var(--color-bg-accent),transparent 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.q-nav{padding:0;background:transparent;border:none}.q-nav-grid{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:var(--space-2)}.q-nav-cell{display:inline-grid;min-width:0;min-height:2.2rem;place-items:center;color:var(--color-muted);font-size:.78rem;font-weight:900;cursor:pointer;background:var(--color-surface-strong);border:1px solid var(--color-border);border-radius:var(--radius-sm);transition:background var(--transition),border-color var(--transition),transform var(--transition)}.q-nav-cell:hover{border-color:var(--color-primary);transform:translateY(-1px)}.q-nav-cell.current{position:relative;z-index:1;border-color:var(--color-heading);box-shadow:0 0 0 3px var(--color-surface-strong),0 0 0 6px 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var(--space-4);border-radius:var(--radius-md)}.status-message.error{background:var(--color-danger-soft)}.status-message.success{background:var(--color-success-soft)}.exam-group-list{display:grid;gap:var(--space-6)}.exam-group-section{display:grid;gap:var(--space-4)}.exam-group-header{display:flex;gap:var(--space-3);align-items:end;justify-content:space-between}.exam-group-header h2{margin:0}.exam-grid,.mode-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:var(--space-4)}.exam-card,.mode-card{position:relative;display:flex;min-height:13rem;flex-direction:column;justify-content:space-between;padding:var(--space-5);overflow:hidden;color:inherit;text-decoration:none;background:var(--color-surface);border:1px solid rgba(219,228,240,.72);border-radius:var(--radius-xl);box-shadow:var(--shadow-sm);transition:transform var(--transition),box-shadow var(--transition),border-color var(--transition)}.exam-card:after,.mode-card:after{position:absolute;top:-3rem;right:-3rem;width:8rem;height:8rem;content:"";background:linear-gradient(135deg,var(--color-primary-soft),var(--color-accent-soft));border-radius:999px}.exam-card:hover,.mode-card:hover{border-color:var(--color-primary);box-shadow:var(--shadow-md);transform:translateY(-3px)}.mode-card.disabled,.mode-card.disabled:hover{pointer-events:none;opacity:.58;box-shadow:var(--shadow-sm);transform:none}.mode-card.recommended{border-color:var(--color-primary);box-shadow:0 0 0 1px var(--color-primary-soft),var(--shadow-md)}.exam-card-cta{display:inline-flex;align-self:flex-start;min-height:2.5rem;align-items:center;padding:.5rem 1rem;margin-top:var(--space-3);font-size:.84rem;font-weight:900;border-radius:var(--radius-md)}.exam-card-status{margin:var(--space-3) 0 0}.mode-activity-card{display:grid;gap:var(--space-2);margin-bottom:var(--space-5)}.mode-activity-card 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rgba(219,228,240,.72);border-radius:var(--radius-lg);box-shadow:var(--shadow-sm);-webkit-backdrop-filter:blur(18px);backdrop-filter:blur(18px)}.quiz-progress{flex:1;min-width:12rem}.quiz-header-actions{display:flex;flex-wrap:wrap;gap:var(--space-2);align-items:center;justify-content:flex-end}.toggle-control{display:inline-flex;align-items:center;gap:var(--space-2);min-height:2.5rem;padding:.25rem 0;color:var(--color-muted);font-size:.84rem;font-weight:800}.toggle-control input{width:auto;margin:0}.question-meta{display:flex;flex-wrap:wrap;gap:var(--space-2);align-items:center;margin-bottom:var(--space-4)}.q-number{margin:0;color:var(--color-primary);font-size:.86rem;font-weight:900;letter-spacing:.08em;text-transform:uppercase}.question-text{margin-bottom:var(--space-5);font-size:clamp(1.05rem,2vw,1.2rem);white-space:pre-wrap}.options{display:flex;flex-direction:column;gap:var(--space-3);margin:var(--space-5) 0}.option{position:relative;display:flex;gap:var(--space-3);align-items:flex-start;width:100%;min-height:3.5rem;padding:var(--space-4);color:var(--color-text);text-align:left;cursor:pointer;background:var(--color-surface-strong);border:2px solid var(--color-border);border-radius:var(--radius-lg);transition:border-color var(--transition),background var(--transition),transform var(--transition)}.option:hover{border-color:var(--color-primary);transform:translateY(-1px)}.option[aria-disabled=true]{cursor:default}.option[aria-disabled=true]:hover{transform:none}.option-key{display:inline-flex;flex:0 0 auto;width:1.9rem;height:1.9rem;align-items:center;justify-content:center;color:var(--color-primary);font-weight:900;background:var(--color-primary-soft);border-radius:999px}.option-text{display:grid;gap:var(--space-2);flex:1}.option-image{display:block;max-width:min(100%,42rem);height:auto;cursor:zoom-in;border:1px solid var(--color-border);border-radius:var(--radius-md);box-shadow:var(--shadow-sm)}.text-en{display:block;font-size:.92rem}.option-indicator{flex:0 0 auto;color:var(--color-muted);font-weight:900}.option.selected{background:var(--color-primary-soft);border-color:var(--color-primary)}.option.correct{background:var(--color-success-soft);border-color:var(--color-success)}.option.wrong{background:var(--color-danger-soft);border-color:var(--color-danger)}.keyboard-hints{margin:calc(-1 * var(--space-3)) 0 var(--space-4);font-size:.84rem;font-weight:700}.question-image-wrap{margin-bottom:var(--space-4)}.image-button{display:block;width:100%;padding:0;overflow:hidden;cursor:zoom-in;background:transparent;border:0;border-radius:var(--radius-xl)}.question-image{display:block;max-width:100%;margin:0 auto;border:1px solid var(--color-border);border-radius:var(--radius-xl);box-shadow:var(--shadow-sm)}.image-hint{margin-top:var(--space-2);color:var(--color-muted);font-size:.84rem;text-align:center}.explanation{padding:var(--space-5);margin:var(--space-4) 0;background:var(--color-bg-accent);border:1px solid var(--color-border);border-radius:var(--radius-lg)}.explanation .markdown-body{line-height:1.75}.explanation .markdown-body>:first-child{margin-top:0}.explanation .markdown-body>:last-child{margin-bottom:0}.explanation .markdown-body p{margin:var(--space-3) 0}.explanation .markdown-body ul,.explanation .markdown-body ol{padding-left:var(--space-5);margin:var(--space-3) 0}.explanation .markdown-body li+li{margin-top:var(--space-2)}.explanation .markdown-body strong{font-weight:900}.result-panel{padding-top:var(--space-4);border-top:1px solid var(--color-border)}.quiz-footer-nav{display:flex;gap:var(--space-3);align-items:center;justify-content:space-between;padding-top:var(--space-4);margin-top:var(--space-5);color:var(--color-muted);font-weight:800;border-top:1px solid var(--color-border)}.result-callout{display:flex;gap:var(--space-3);align-items:center;margin-bottom:var(--space-4);font-size:1.05rem;font-weight:900}.result-score{display:grid;grid-template-columns:repeat(auto-fit,minmax(9rem,1fr));gap:var(--space-3);margin:var(--space-5) 0}.review-list{display:grid;gap:var(--space-3);margin:var(--space-5) 0}.review-item{padding:var(--space-4);background:var(--color-bg-accent);border:1px solid var(--color-border);border-radius:var(--radius-lg)}.review-item summary{display:flex;gap:var(--space-3);align-items:center;justify-content:space-between;font-weight:900;cursor:pointer}.score-tile{padding:var(--space-4);background:var(--color-bg-accent);border:1px solid var(--color-border);border-radius:var(--radius-lg)}.score-value{margin:0;color:var(--color-heading);font-size:2rem;font-weight:900;line-height:1}.score-label{margin:var(--space-2) 0 0;color:var(--color-muted);font-size:.86rem;font-weight:700}.banner{padding:var(--space-3) var(--space-4);margin-bottom:var(--space-4);color:var(--color-warning);background:var(--color-warning-soft);border:1px solid rgba(217,119,6,.24);border-radius:var(--radius-md)}.banner-dismissible{display:flex;gap:var(--space-3);align-items:flex-start;justify-content:space-between}.banner-dismissible p{margin:0}.banner-close{flex:0 0 auto;width:2rem;height:2rem;color:var(--color-warning);font-weight:900;cursor:pointer;background:transparent;border:1px solid rgba(217,119,6,.24);border-radius:var(--radius-sm)}.keyboard-hints-details{margin-bottom:var(--space-4)}.keyboard-hints-details summary{cursor:pointer;font-size:.82rem;font-weight:800}.loading,.loading-card{display:grid;min-height:12rem;place-items:center;text-align:center}.skeleton-page{animation:fade-in var(--transition)}.skeleton-stack{display:grid;gap:var(--space-3)}.skeleton-card{pointer-events:none}.skeleton-line{display:block;width:100%;height:.95rem;overflow:hidden;background:linear-gradient(90deg,var(--color-primary-soft),var(--color-accent-soft),var(--color-primary-soft));background-size:220% 100%;border-radius:999px;animation:skeleton-shimmer 1.2s ease-in-out infinite}.skeleton-line.short{width:7rem}.skeleton-line.medium{width:min(16rem,70%)}.skeleton-line.wide{width:min(28rem,100%)}.skeleton-line.title{width:min(26rem,90%);height:2.6rem;border-radius:var(--radius-md)}.skeleton-line.option-skeleton{height:4rem;border-radius:var(--radius-lg)}.spinner{width:2.5rem;height:2.5rem;border:4px solid var(--color-primary-soft);border-top-color:var(--color-primary);border-radius:999px;animation:spin .8s linear infinite}.spinner-label{margin:var(--space-4) 0 0;color:var(--color-muted);font-weight:700}.empty-state,.error-state{text-align:center}.error-state-icon,.empty-state-icon{display:inline-grid;width:3rem;height:3rem;margin-bottom:var(--space-3);place-items:center;color:var(--color-primary);background:var(--color-primary-soft);border-radius:999px}.error-boundary{display:grid;min-height:100vh;padding:var(--space-6);place-items:center}.error-boundary .error-state{width:min(42rem,100%)}.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}.auth-links{margin-top:var(--space-4)}.toast{position:sticky;top:var(--space-4);z-index:20;display:flex;flex-wrap:wrap;gap:var(--space-3);align-items:center;justify-content:space-between;padding:var(--space-3) var(--space-4);margin-bottom:var(--space-4);color:var(--color-warning);background:var(--color-warning-soft);border:1px solid var(--color-warning);border-radius:var(--radius-md);box-shadow:var(--shadow-sm)}.toast-close{min-height:2rem;color:inherit;cursor:pointer;background:transparent;border:0}.dialog-backdrop,.lightbox{position:fixed;top:0;right:0;bottom:0;left:0;z-index:80;display:grid;place-items:center;padding:var(--space-4);background:#0f172a94}.dialog{width:min(28rem,100%);padding:var(--space-5)}.dialog-actions{display:flex;flex-wrap:wrap;gap:var(--space-3);justify-content:flex-end;margin-top:var(--space-5)}.lightbox{z-index:90;overflow:auto}.lightbox-image{display:block;max-width:min(100%,1200px);max-height:86vh;touch-action:pinch-zoom;border-radius:var(--radius-lg);box-shadow:var(--shadow-md)}.lightbox-close{position:fixed;top:var(--space-4);right:var(--space-4);z-index:91;padding:.55rem .85rem;color:#fff;font-weight:900;cursor:pointer;background:#0f172ab8;border:1px solid rgba(255,255,255,.24);border-radius:var(--radius-md)}@keyframes spin{to{transform:rotate(360deg)}}@keyframes skeleton-shimmer{to{background-position:-220% 0}}@keyframes fade-in{0%{opacity:0;transform:translateY(4px)}to{opacity:1;transform:translateY(0)}}@media (prefers-reduced-motion: reduce){*,*:before,*:after{scroll-behavior:auto!important;animation-duration:1ms!important;animation-iteration-count:1!important;transition-duration:1ms!important}}@media (max-width: 960px){.app-shell{display:block}.shell-topbar{position:sticky;top:0;z-index:30;display:flex;align-items:center;justify-content:space-between;padding:var(--space-3) var(--space-4);background:var(--color-surface);border-bottom:1px solid var(--color-border);-webkit-backdrop-filter:blur(18px);backdrop-filter:blur(18px)}.shell-topbar-actions .theme-switcher{min-width:8rem}.shell-topbar-actions .theme-switcher-note{display:none}.menu-button{display:inline-flex;align-items:center;gap:var(--space-2);min-height:2.5rem;padding:.45rem .75rem;color:var(--color-heading);font-weight:900;cursor:pointer;background:var(--color-primary-soft);border:1px solid var(--color-border);border-radius:var(--radius-md)}.sidebar{position:fixed;inset:0 auto 0 0;z-index:40;width:min(22rem,calc(100vw - 3rem));transform:translate(-105%);transition:transform .22s ease}.sidebar.open{transform:translate(0)}.scrim{position:fixed;top:0;right:0;bottom:0;left:0;z-index:35;display:block;background:#0f172a70}.shell-main{width:100%;padding:var(--space-4)}.quiz-mobile-nav{display:flex;flex-wrap:wrap;gap:var(--space-2);margin-bottom:var(--space-4)}}@media (max-width: 720px){.hero,.page-header,.quiz-header{grid-template-columns:1fr;align-items:flex-start}.hero,.page-header{display:block}.quiz-header{position:static;flex-wrap:wrap}.quiz-progress{flex-basis:100%}.auth-card,.question-card,.result-card,.empty-state,.error-state,.loading-card{padding:var(--space-5)}}