:root{--bg-primary: #0d0d0d;--bg-secondary: #1a1a1a;--bg-tertiary: #242424;--bg-elevated: #2d2d2d;--accent: #4dabf7;--accent-hover: #74c0fc;--accent-muted: rgba(77, 171, 247, .15);--band-1: #ff6b6b;--band-2: #ffa94d;--band-3: #ffe066;--band-4: #69db7c;--band-5: #4dabf7;--band-6: #9775fa;--band-7: #f06595;--band-8: #e599f7;--spectrum-low: #ff6b6b;--spectrum-mid: #69db7c;--spectrum-high: #4dabf7;--text-primary: #ffffff;--text-secondary: #888888;--text-muted: #555555;--border-color: #333333;--font-size-2xs: .625rem;--font-size-xs: .75rem;--font-size-sm: .875rem;--font-size-base: 1rem;--font-size-lg: 1.25rem;--font-size-xl: 1.5rem;--font-weight-normal: 400;--font-weight-medium: 500;--font-weight-semibold: 600;--btn-size-primary: 72px;--btn-size-secondary: 48px;--btn-size-tertiary: 36px;--shadow-sm: 0 1px 2px rgba(0, 0, 0, .3);--shadow-md: 0 4px 8px rgba(0, 0, 0, .4);--glow-accent: 0 0 16px rgba(77, 171, 247, .3);--grid-color: rgba(255, 255, 255, .06);--spacing-xs: 4px;--spacing-sm: 8px;--spacing-md: 16px;--spacing-lg: 24px;--spacing-xl: 32px;--radius-sm: 4px;--radius-md: 8px;--radius-lg: 12px;--radius-xl: 16px;--transition-fast: .15s ease;--transition-normal: .25s ease;--transition-slow: .4s ease;--font-mono: "JetBrains Mono", "SF Mono", "Consolas", monospace;--font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif}*{margin:0;padding:0;box-sizing:border-box}:focus-visible{outline:2px solid var(--accent);outline-offset:2px}button:focus-visible,.btn:focus-visible,.play-button:focus-visible,.source-chip:focus-visible,.compare-btn:focus-visible,.lesson-card:focus-visible{outline:2px solid var(--accent);outline-offset:2px;box-shadow:0 0 0 4px var(--accent-muted)}html,body,#root{height:100%;width:100%}body{font-family:var(--font-sans);background:var(--bg-primary);color:var(--text-primary);-webkit-font-smoothing:antialiased;-moz-osx-font-smoothing:grayscale;overflow:hidden}.app{display:grid;grid-template-rows:auto 1fr 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var(--spacing-md);background:var(--bg-tertiary);border-radius:var(--radius-md)}.header__right{display:flex;align-items:center;gap:var(--spacing-md)}.language-switcher{display:flex;gap:var(--spacing-xs)}.lang-btn{padding:var(--spacing-xs) var(--spacing-sm);font-family:inherit;font-size:var(--font-size-xs);font-weight:var(--font-weight-medium);color:var(--text-secondary);background:transparent;border:1px solid var(--border-color);border-radius:var(--radius-sm);cursor:pointer;transition:all var(--transition-fast)}.lang-btn:hover{color:var(--text-primary);border-color:var(--text-muted)}.lang-btn--active{color:var(--accent);border-color:var(--accent);background:var(--accent-muted)}.main{position:relative;display:flex;flex-direction:column;overflow:hidden;min-height:0}.eq-container{flex:1;position:relative;display:flex;align-items:stretch;justify-content:center;padding:var(--spacing-md);min-height:0}.eq-display{position:relative;width:100%;height:100%;background:var(--bg-secondary);border-radius:var(--radius-lg);border:1px solid var(--border-color);overflow:hidden;padding:var(--spacing-sm) 0}.controls{grid-column:1 / -1;display:grid;grid-template-columns:1fr auto 1fr;align-items:center;gap:var(--spacing-lg);padding:var(--spacing-sm) var(--spacing-lg);background:var(--bg-secondary);border-top:1px solid var(--border-color)}.controls__left{display:flex;align-items:center;gap:var(--spacing-sm);justify-self:start}.controls__center{display:flex;align-items:center;justify-content:center}.controls__right{display:flex;align-items:center;gap:var(--spacing-md);justify-self:end}.ios-hint{grid-column:1 / -1;display:flex;align-items:center;justify-content:center;gap:var(--spacing-sm);padding:var(--spacing-xs) var(--spacing-md);background:var(--bg-tertiary);border-radius:var(--radius-sm);font-size:var(--font-size-xs);color:var(--text-secondary)}.ios-hint__dismiss{display:flex;align-items:center;justify-content:center;padding:var(--spacing-2xs);background:transparent;border:none;border-radius:var(--radius-sm);color:var(--text-secondary);cursor:pointer;opacity:.7;transition:opacity var(--transition-fast)}.ios-hint__dismiss:hover{opacity:1}.btn{display:inline-flex;align-items:center;justify-content:center;gap:var(--spacing-sm);padding:var(--spacing-sm) 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var(--spacing-md);color:var(--text-secondary);background:transparent;border-color:transparent}.btn--reset:hover{color:var(--text-primary);background:var(--bg-tertiary);border-color:var(--border-color)}.play-button{display:flex;align-items:center;justify-content:center;width:var(--btn-size-primary);height:var(--btn-size-primary);padding:0;font-family:inherit;color:var(--text-primary);background:var(--accent);border:none;border-radius:50%;cursor:pointer;transition:all var(--transition-fast);box-shadow:var(--glow-accent)}.play-button:hover{background:var(--accent-hover);box-shadow:0 0 24px #4dabf780;transform:scale(1.05)}.play-button:active{transform:scale(.98)}.play-button svg{width:28px;height:28px}.source-selector{display:flex;gap:2px;background:var(--bg-tertiary);border-radius:var(--radius-xl);padding:2px}.source-chip{height:32px;padding:0 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var(--accent);outline-offset:2px}.lesson-panel__content{flex:1;padding:var(--spacing-md);padding-right:var(--spacing-lg);overflow-y:auto;overflow-x:hidden}.lesson-panel__instruction{font-size:var(--font-size-sm);line-height:1.6;color:var(--text-primary);word-wrap:break-word;overflow-wrap:break-word}.lesson-panel__result{margin-bottom:var(--spacing-sm)}.lesson-panel__result--correct{color:var(--band-4);font-size:var(--font-size-lg);font-weight:var(--font-weight-semibold)}.lesson-panel__result--incorrect{color:var(--band-1);font-size:var(--font-size-lg);font-weight:var(--font-weight-semibold)}.lesson-panel__hint{margin-top:var(--spacing-sm);font-size:var(--font-size-sm);color:var(--text-secondary)}.lesson-panel__question{margin-bottom:var(--spacing-md)}.lesson-panel__options{display:flex;flex-wrap:wrap;gap:var(--spacing-sm)}.lesson-panel__actions{display:flex;gap:var(--spacing-sm);padding:var(--spacing-md);border-top:1px solid var(--border-color)}.lesson-panel__actions 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var(--transition-fast)}.lesson-card:hover{border-color:var(--accent)}.lesson-card__title{font-size:var(--font-size-sm);font-weight:var(--font-weight-medium);color:var(--text-primary);margin-bottom:var(--spacing-xs)}.lesson-card__description{font-size:var(--font-size-xs);color:var(--text-secondary);margin-bottom:var(--spacing-xs)}.lesson-card__difficulty{font-size:var(--font-size-2xs);color:var(--text-muted)}.lesson-loading{padding:var(--spacing-lg);text-align:center;color:var(--text-secondary)}.volume-control{display:flex;align-items:center;gap:var(--spacing-sm)}.volume-control__icon{color:var(--text-secondary)}.volume-control__label{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0,0,0,0)}.volume-control__slider{width:80px;height:4px;appearance:none;background:var(--bg-tertiary);border-radius:2px;cursor:pointer}.volume-control__slider::-webkit-slider-thumb{appearance:none;width:14px;height:14px;background:var(--text-primary);border-radius:50%;cursor:pointer;transition:transform 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var(--transition-fast)}.eq-node:hover{transform:scale(1.2)}.eq-node:active{cursor:grabbing}.eq-node--band-1{background:var(--band-1)}.eq-node--band-2{background:var(--band-2)}.eq-node--band-3{background:var(--band-3)}.eq-node--band-4{background:var(--band-4)}.eq-node--band-5{background:var(--band-5)}.eq-node--band-6{background:var(--band-6)}.eq-node--band-7{background:var(--band-7)}.eq-node--band-8{background:var(--band-8)}.eq-node--band-1:hover,.eq-node--band-1:active{box-shadow:0 0 12px var(--band-1)}.eq-node--band-2:hover,.eq-node--band-2:active{box-shadow:0 0 12px var(--band-2)}.eq-node--band-3:hover,.eq-node--band-3:active{box-shadow:0 0 12px var(--band-3)}.eq-node--band-4:hover,.eq-node--band-4:active{box-shadow:0 0 12px var(--band-4)}.eq-node--band-5:hover,.eq-node--band-5:active{box-shadow:0 0 12px var(--band-5)}.eq-node--band-6:hover,.eq-node--band-6:active{box-shadow:0 0 12px var(--band-6)}.eq-node--band-7:hover,.eq-node--band-7:active{box-shadow:0 0 12px 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var(--spacing-md);font-family:inherit;font-size:var(--font-size-sm);color:var(--text-primary);background:var(--bg-elevated);border:1px solid var(--border-color);border-radius:var(--radius-sm);cursor:pointer;transition:all var(--transition-fast)}.error-boundary__button:hover{background:var(--bg-tertiary);border-color:var(--text-secondary)}.error-boundary__details{margin-top:var(--spacing-lg);text-align:left;color:var(--text-muted);font-size:var(--font-size-sm)}.error-boundary__pre{margin-top:var(--spacing-sm);padding:var(--spacing-sm);background:var(--bg-secondary);border-radius:var(--radius-sm);font-family:var(--font-mono);font-size:var(--font-size-xs);overflow:auto}.animate-glow{animation:glow 1.5s ease-in-out infinite}.compare-grid{display:flex;gap:var(--spacing-sm);flex-wrap:wrap;margin-bottom:var(--spacing-sm)}.compare-btn{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:var(--spacing-md);background:var(--bg-tertiary);border:1px solid 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var(--accent-muted)}.compare-hint{font-size:var(--font-size-xs);color:var(--text-secondary);display:flex;align-items:center;gap:6px}.playing-dot{color:var(--accent);animation:pulse 1.5s infinite}.compare-hint__resume{padding:0;display:flex;align-items:center;gap:6px}.compare-hint__link{color:var(--accent);text-decoration:underline}.quiz-indicator{display:flex;align-items:center;gap:8px;margin-bottom:1rem;font-size:var(--font-size-xs);color:var(--text-secondary)}.quiz-indicator__label{font-weight:700;color:var(--accent);min-width:80px}.quiz-indicator__progress{flex:1;height:4px;background:var(--bg-tertiary);border-radius:2px;overflow:hidden;max-width:120px}.quiz-indicator__bar{height:100%;background:var(--accent);transform-origin:right;animation:countdown linear forwards}@media(max-width:768px){.app,.app--has-sidebar{grid-template-columns:1fr!important}.main,.header,.controls{grid-column:1 / -1!important;width:100%!important}.lesson-browser,.lesson-panel{position:fixed;top:auto;bottom:calc(80px + env(safe-area-inset-bottom));left:var(--spacing-md);right:var(--spacing-md);width:auto;max-height:220px;border:1px solid var(--border-color);border-radius:var(--radius-lg);box-shadow:0 -4px 20px #00000080;z-index:100}.controls{grid-template-columns:1fr auto 1fr;gap:var(--spacing-sm);padding:var(--spacing-sm) var(--spacing-md)}.play-button{width:56px;height:56px}.play-button svg{width:22px;height:22px}.source-chip{padding:0 var(--spacing-sm);font-size:var(--font-size-2xs);height:28px}.source-selector{padding:1px}.volume-control__slider{width:50px}.volume-control__value{display:none}.btn--reset{font-size:var(--font-size-2xs);padding:var(--spacing-xs) var(--spacing-sm)}.eq-container{padding:var(--spacing-sm)}}@media(max-width:480px){.header{padding:var(--spacing-xs) var(--spacing-sm)}.header__title{font-size:var(--font-size-base)}.header__subtitle{display:none}.header__logo 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var(--spacing-md);gap:var(--spacing-xs)}.lesson-panel__header-row{margin-bottom:var(--spacing-xs)}.lesson-panel__title{font-size:var(--font-size-sm)}.lesson-panel__progress-dot{width:10px;height:10px}.lesson-panel__content{padding:var(--spacing-sm) var(--spacing-md);max-height:80px;overflow-y:auto}.lesson-panel__instruction{font-size:var(--font-size-xs);line-height:1.5}.lesson-panel__actions{padding:var(--spacing-sm) var(--spacing-md);gap:var(--spacing-xs)}.lesson-panel__actions .btn{font-size:var(--font-size-xs);padding:var(--spacing-xs) var(--spacing-sm);height:32px}.lesson-panel__content:has(.comparison-panel){max-height:160px}.comparison-panel .lesson-panel__instruction{font-size:var(--font-size-xs);margin-bottom:var(--spacing-sm)}.compare-grid{gap:var(--spacing-xs)}.compare-btn{padding:var(--spacing-xs) var(--spacing-sm);min-height:48px}.compare-btn__freq{font-size:var(--font-size-sm)}.compare-btn__status,.compare-hint{font-size:8px}.eq-container{padding:var(--spacing-xs)}.eq-display{border-radius:var(--radius-md)}}.loading-spinner{display:flex;flex-direction:column;align-items:center;gap:var(--spacing-md);padding:var(--spacing-lg)}.loading-spinner--small{--size: 24px}.loading-spinner--medium{--size: 40px}.loading-spinner--large{--size: 60px}.loading-spinner__circle{width:var(--size);height:var(--size)}.loading-spinner__circle svg{width:100%;height:100%;animation:spin 1s linear infinite}.loading-spinner__path{animation:dash 1.5s ease-in-out infinite}.loading-spinner__message{color:var(--text-secondary);font-size:.875rem;text-align:center}@keyframes spin{to{transform:rotate(360deg)}}@keyframes dash{0%{stroke-dashoffset:31.416}50%{stroke-dashoffset:0}to{stroke-dashoffset:-31.416}}