:root{--font-sans: "Plus Jakarta Sans", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;--font-mono: "JetBrains Mono", monospace;--bg-page: #F8FAFC;--bg-card: #FFFFFF;--bg-card-hover: #F8FAFC;--bg-surface: #F1F5F9;--bg-subtle: #F8FAFC;--border-subtle: #E2E8F0;--border-card: #E2E8F0;--border-hover: #CBD5E1;--border-focus: #EA580C;--text-primary: #0F172A;--text-secondary: #334155;--text-muted: #64748B;--text-faint: #94A3B8;--aws-orange: #EA580C;--aws-orange-light: #FFF7ED;--aws-orange-border: #FED7AA;--aws-orange-dark: #C2410C;--aws-orange-glow: rgba(234, 88, 12, .12);--aws-navy: #0F172A;--aws-navy-light: #1E293B;--color-success: #16A34A;--color-success-bg: #F0FDF4;--color-success-border: #BBF7D0;--color-success-text: #15803D;--color-danger: #DC2626;--color-danger-bg: #FEF2F2;--color-danger-border: #FECACA;--color-danger-text: #B91C1C;--color-warning: #D97706;--color-warning-bg: #FFFBEB;--color-warning-border: #FDE68A;--color-warning-text: #B45309;--color-info: #2563EB;--color-info-bg: #EFF6FF;--color-info-border: #BFDBFE;--color-info-text: #1D4ED8;--color-purple: #7C3AED;--color-purple-bg: #F5F3FF;--color-purple-border: #DDD6FE;--radius-sm: 6px;--radius-md: 10px;--radius-lg: 14px;--radius-xl: 20px;--shadow-sm: 0 1px 3px 0 rgba(15, 23, 42, .05), 0 1px 2px -1px rgba(15, 23, 42, .05);--shadow-md: 0 4px 6px -1px rgba(15, 23, 42, .06), 0 2px 4px -2px rgba(15, 23, 42, .04);--shadow-lg: 0 10px 15px -3px rgba(15, 23, 42, .07), 0 4px 6px -4px rgba(15, 23, 42, .04);--shadow-glow: 0 0 20px rgba(234, 88, 12, .15);--mobile-bp: 768px}[data-theme=dark]{--bg-page: #080C14;--bg-card: #0F172A;--bg-card-hover: #15223C;--bg-surface: #1E293B;--bg-subtle: #131D33;--border-subtle: #1E2E4A;--border-card: #1E2E4A;--border-hover: #334B73;--border-focus: #FF9900;--text-primary: #F8FAFC;--text-secondary: #CBD5E1;--text-muted: #94A3B8;--text-faint: #64748B;--aws-orange: #FF9900;--aws-orange-light: rgba(255, 153, 0, .12);--aws-orange-border: rgba(255, 153, 0, .3);--aws-orange-dark: #EC7211;--aws-orange-glow: rgba(255, 153, 0, .25);--aws-navy: #0F172A;--aws-navy-light: #1E293B;--color-success: #10B981;--color-success-bg: rgba(16, 185, 129, .12);--color-success-border: rgba(16, 185, 129, .3);--color-success-text: #34D399;--color-danger: #EF4444;--color-danger-bg: rgba(239, 68, 68, .12);--color-danger-border: rgba(239, 68, 68, .3);--color-danger-text: #F87171;--color-warning: #F59E0B;--color-warning-bg: rgba(245, 158, 11, .12);--color-warning-border: rgba(245, 158, 11, .3);--color-warning-text: #FBBF24;--color-info: #0284C7;--color-info-bg: rgba(2, 132, 199, .12);--color-info-border: rgba(2, 132, 199, .3);--color-info-text: #38BDF8;--shadow-sm: 0 2px 8px rgba(0, 0, 0, .3);--shadow-md: 0 4px 20px rgba(0, 0, 0, .4)}*{box-sizing:border-box;margin:0;padding:0}body{font-family:var(--font-sans);background-color:var(--bg-page);color:var(--text-primary);min-height:100vh;line-height:1.55;-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;overflow-x:hidden;transition:background-color .2s ease,color .2s ease}::-webkit-scrollbar{width:8px;height:8px}::-webkit-scrollbar-track{background:var(--bg-page)}::-webkit-scrollbar-thumb{background:var(--border-hover);border-radius:4px}::-webkit-scrollbar-thumb:hover{background:var(--text-muted)}.desktop-only{display:initial}.mobile-only{display:none!important}@media(max-width:768px){.desktop-only{display:none!important}.mobile-only{display:flex!important}}.app-container{display:flex;flex-direction:column;min-height:100vh;background-color:var(--bg-page)}.main-content{flex:1;max-width:1400px;width:100%;margin:0 auto;padding:10px 16px 24px}.navbar{position:sticky;top:0;z-index:50;background:#ffffffeb;backdrop-filter:blur(14px);-webkit-backdrop-filter:blur(14px);border-bottom:1px solid var(--border-subtle);box-shadow:var(--shadow-sm);display:flex;flex-direction:column}[data-theme=dark] .navbar{background:#0b101ae0}.nav-top-row{display:flex;align-items:center;justify-content:space-between;gap:16px;padding:8px 20px}.nav-brand{display:flex;align-items:center;gap:12px;cursor:pointer;text-decoration:none;flex-shrink:0}.brand-icon{width:36px;height:36px;border-radius:var(--radius-md);box-shadow:var(--shadow-sm)}.brand-title{font-size:1.15rem;font-weight:800;letter-spacing:-.02em;color:var(--text-primary);line-height:1.2}.brand-badge{display:inline-block;font-size:.68rem;font-weight:700;text-transform:uppercase;letter-spacing:.05em;color:var(--aws-orange);background:var(--aws-orange-light);border:1px solid var(--aws-orange-border);padding:2px 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strong{color:var(--aws-orange);font-weight:700}.mobile-progress-pct{font-size:.75rem;color:var(--text-faint);margin-left:4px}.mobile-progress-bar-track{width:100%;height:6px;background:var(--border-subtle);border-radius:3px;overflow:hidden;margin-bottom:8px}.mobile-progress-bar-fill{height:100%;background:linear-gradient(90deg,var(--aws-orange),var(--aws-orange-dark));border-radius:3px;transition:width .5s ease;min-width:2px}.mobile-progress-details{display:flex;gap:14px;font-size:.75rem;font-weight:600}.mobile-stat-correct{color:var(--color-success)}.mobile-stat-wrong{color:var(--color-danger)}.mobile-stat-unseen{color:var(--text-muted)}.mobile-nav-list{display:flex;flex-direction:column;gap:4px}.mobile-nav-item{display:flex;align-items:center;gap:12px;padding:12px 14px;background:transparent;border:1px solid transparent;border-radius:var(--radius-md);font-size:.9rem;font-weight:600;color:var(--text-secondary);cursor:pointer;transition:all .12s 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input{flex:1;background:transparent;border:none;outline:none;font-family:var(--font-sans);font-size:.9rem;color:var(--text-primary)}.search-box input::placeholder{color:var(--text-faint)}select.filter-select{background:var(--bg-surface);color:var(--text-primary);border:1px solid var(--border-subtle);border-radius:var(--radius-md);padding:6px 10px;font-size:.82rem;font-weight:500;outline:none;cursor:pointer;transition:all .15s ease;width:100%;max-width:320px}select.filter-select:focus{border-color:var(--border-focus);background:var(--bg-card)}.q-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:6px}.q-grid-btn{display:flex;align-items:center;justify-content:center;height:36px;border-radius:var(--radius-sm);font-family:var(--font-mono);font-size:.8rem;font-weight:600;background:var(--bg-surface);color:var(--text-secondary);border:1px solid var(--border-subtle);cursor:pointer;position:relative;transition:all .12s ease}.q-grid-btn:hover{border-color:var(--border-hover);background:var(--bg-card)}.q-grid-btn.current{border-color:var(--aws-orange);box-shadow:0 0 0 2px var(--aws-orange);color:var(--aws-orange);font-weight:700}.q-grid-btn.answered{background:var(--aws-orange-light);border-color:var(--aws-orange-border);color:var(--aws-orange-dark)}.q-grid-btn.flagged:after{content:"";position:absolute;top:3px;right:3px;width:6px;height:6px;border-radius:50%;background:#f59e0b}.timer-pill{display:flex;align-items:center;gap:8px;font-family:var(--font-mono);font-size:1.15rem;font-weight:700;color:var(--text-primary);background:var(--bg-surface);padding:8px 16px;border-radius:var(--radius-md);border:1px solid var(--border-subtle)}.timer-pill.urgent{color:var(--color-danger);background:var(--color-danger-bg);border-color:var(--color-danger-border);animation:pulse-urgent 1.5s infinite}@keyframes 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var(--border-subtle);margin-top:8px}.filter-controls-wrap.expanded{display:block}.filter-controls-row{flex-direction:column;align-items:stretch;gap:10px}.seen-toggle-group{width:100%;justify-content:center}.seen-toggle-btn{flex:1;justify-content:center;padding:8px 6px;font-size:.75rem}.filter-selects-row{flex-direction:column;gap:8px}.filter-select-group{width:100%}select.filter-select{flex:1;width:100%;max-width:none;padding:8px 10px;font-size:.82rem}.jump-form{width:100%}.jump-search-box{flex:1}.jump-search-box input{width:100%}.practice-question-card{padding:12px 14px}.practice-header{gap:8px;margin-bottom:10px;padding-bottom:8px}.stepper-info{gap:6px}.q-badge{font-size:.75rem;padding:3px 8px}.type-pill{font-size:.7rem;padding:2px 6px}.seen-indicator{font-size:.65rem;padding:2px 6px}.question-title{font-size:.9rem;line-height:1.45}.option-item{padding:12px;gap:10px}.option-letter{min-width:28px;height:28px;font-size:.8rem}.option-text{font-size:.85rem}.practice-actions{gap:10px}.practice-actions .btn{padding:8px 12px;font-size:.8rem}.stats-grid{grid-template-columns:repeat(2,1fr);gap:8px}.stat-card{padding:14px;gap:10px}.stat-icon-wrap{width:36px;height:36px}.stat-val{font-size:1.2rem}.stat-lbl{font-size:.7rem}.q-grid{grid-template-columns:repeat(4,1fr)}.explanation-card{padding:10px 12px}.explanation-answer-banner{padding:10px 12px;gap:8px}}@media(max-width:400px){.brand-title{font-size:.85rem}.brand-badge{display:none}.nav-top-row{padding:6px 10px;gap:8px}.theme-toggle-btn{width:34px;height:34px}.hamburger-btn{width:36px;height:36px}.practice-question-card{padding:10px;border-radius:var(--radius-md)}.option-item{padding:10px}.stats-grid{grid-template-columns:1fr}.q-grid{grid-template-columns:repeat(3,1fr)}}