:root{color-scheme:light;--font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "SF Pro Display", "Helvetica Neue", sans-serif;--color-label: #000000;--color-label-secondary: rgba(60, 60, 67, .6);--color-fill: #f2f2f7;--color-secondary-grouped: #ffffff;--color-separator: rgba(60, 60, 67, .29);--color-separator-opaque: #c6c6c8;--color-tint: #6366f1;--color-tint-hover: #4f46e5;--color-green: #34c759;--color-orange: #ff9500;--color-red: #ff3b30;--color-gray-fill: #e5e5ea;--color-gray-fill-secondary: #f2f2f7;--overlay-bg: rgba(0, 0, 0, .4);--radius-control: 10px;--radius-card: 12px;--radius-pill: 999px;--space-1: 4px;--space-2: 8px;--space-3: 12px;--space-4: 16px;--space-5: 20px;--space-6: 24px;--space-8: 32px;--touch-min: 44px;--font-caption: .8125rem;--font-body: 1rem;--font-title: 1.0625rem;--font-page-title: 1.375rem}@media(prefers-color-scheme:dark){:root{color-scheme:dark;--color-label: #ffffff;--color-label-secondary: rgba(235, 235, 245, .6);--color-fill: #000000;--color-secondary-grouped: #1c1c1e;--color-separator: rgba(84, 84, 88, .65);--color-separator-opaque: #38383a;--color-tint: #818cf8;--color-tint-hover: #6366f1;--color-green: #30d158;--color-orange: #ff9f0a;--color-red: #ff453a;--color-gray-fill: #3a3a3c;--color-gray-fill-secondary: #2c2c2e;--overlay-bg: rgba(0, 0, 0, .55)}}*{box-sizing:border-box}body{margin:0;min-height:100vh;font-family:var(--font-sans);font-size:var(--font-body);line-height:1.47;color:var(--color-label);background:var(--color-fill);-webkit-font-smoothing:antialiased}a{color:inherit;text-decoration:none}button,input,select,textarea{font:inherit;color:inherit}:focus-visible{outline:2px solid var(--color-tint);outline-offset:2px}.caption{font-size:var(--font-caption);color:var(--color-label-secondary)}.muted{color:var(--color-label-secondary)}.page-title{font-size:var(--font-page-title);font-weight:600;line-height:1.25;margin:0 0 var(--space-3)}.page-section{max-width:960px;margin:0 auto;padding:var(--space-6) 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img{border-radius:var(--radius-pill)}.app-main{flex:1}.btn{display:inline-flex;align-items:center;justify-content:center;min-height:var(--touch-min);border:none;border-radius:var(--radius-control);padding:0 var(--space-4);cursor:pointer;font-weight:500;transition:background .15s ease,opacity .15s ease;white-space:nowrap}.btn-sm{min-height:36px;padding:0 var(--space-3);font-size:var(--font-caption)}.btn:disabled{opacity:.45;cursor:not-allowed}.btn-primary{background:var(--color-tint);color:#fff}.btn-primary:hover:not(:disabled){background:var(--color-tint-hover)}.btn-secondary{background:var(--color-gray-fill);color:var(--color-label)}.btn-ghost{background:transparent;color:var(--color-tint)}.btn-danger-text{color:var(--color-red)}.landing{max-width:640px;margin:0 auto;padding:var(--space-8) var(--space-5);text-align:center}.lead{color:var(--color-label-secondary);margin:0 0 var(--space-6)}.error-banner{color:var(--color-red);margin-bottom:var(--space-4)}.dashboard-header,.page-toolbar{display:flex;align-items:flex-start;justify-content:space-between;gap:var(--space-4);margin-bottom:var(--space-6)}.back-link{display:inline-block;margin-bottom:var(--space-2);color:var(--color-tint);font-size:var(--font-caption)}.toolbar-row{display:flex;gap:var(--space-3);margin-bottom:var(--space-4)}.search-input,.text-input,.toolbar-select,.text-area{width:100%;min-height:var(--touch-min);border:.5px solid var(--color-separator-opaque);border-radius:var(--radius-control);padding:var(--space-3);background:var(--color-secondary-grouped)}.toolbar-select{width:auto}.list-group{display:flex;flex-direction:column;gap:var(--space-3)}.list-row{display:flex;align-items:center;justify-content:space-between;gap:var(--space-4);padding:var(--space-4);background:var(--color-secondary-grouped);border-radius:var(--radius-card);border:.5px solid var(--color-separator)}.list-row h3{margin:0 0 var(--space-1);font-size:var(--font-title)}.empty-state{text-align:center;padding:var(--space-8) var(--space-4)}.card-form{display:grid;grid-template-columns:1fr 1fr auto;gap:var(--space-3);margin-bottom:var(--space-5)}.data-table{width:100%;border-collapse:collapse;background:var(--color-secondary-grouped);border-radius:var(--radius-card);overflow:hidden}.data-table th,.data-table td{padding:var(--space-3) var(--space-4);border-bottom:.5px solid var(--color-separator);text-align:left}.data-table th{font-size:var(--font-caption);color:var(--color-label-secondary)}.study-page{max-width:640px;text-align:center}.study-header{text-align:left;margin-bottom:var(--space-6)}.flash-card{width:100%;min-height:280px;border:none;background:transparent;cursor:pointer;perspective:1000px;margin-bottom:var(--space-6)}.flash-card-inner{position:relative;width:100%;min-height:280px;transition:transform .5s;transform-style:preserve-3d}.flash-card--flipped .flash-card-inner{transform:rotateY(180deg)}.flash-card-face{position:absolute;top:0;right:0;bottom:0;left:0;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:var(--space-6);border-radius:var(--radius-card);background:var(--color-secondary-grouped);border:.5px solid var(--color-separator);backface-visibility:hidden}.flash-card-back{transform:rotateY(180deg);text-align:left;align-items:flex-start}.flash-card-phonetic{font-size:var(--font-caption);color:var(--color-label-secondary);margin-bottom:var(--space-3)}.flash-card-meaning{white-space:pre-line;font-size:1.25rem;font-weight:600;line-height:1.5;width:100%}.flash-card--immersive .flash-card-meaning{font-size:clamp(1.125rem,3.5vw,1.5rem);font-weight:500}.flash-card-label{font-size:var(--font-caption);color:var(--color-label-secondary);margin-bottom:var(--space-3)}.flash-card-face p{margin:0;font-size:1.75rem;font-weight:600}.review-controls{display:grid;grid-template-columns:repeat(2,1fr);gap:var(--space-3)}@media(min-width:640px){.review-controls{grid-template-columns:repeat(4,1fr)}}.review-btn{min-height:56px;color:#fff}.review-btn--again{background:var(--color-red)}.review-btn--hard{background:var(--color-orange)}.review-btn--good{background:var(--color-tint)}.review-btn--easy{background:var(--color-green)}.stats-panel{display:grid;gap:var(--space-6)}@media(min-width:720px){.stats-panel{grid-template-columns:220px 1fr;align-items:center}}.stats-ring{width:180px;height:180px;margin:0 auto;border-radius:50%;background:conic-gradient(var(--color-green) calc(var(--mastery) * 1%),var(--color-gray-fill) 0);display:grid;place-items:center}.stats-ring-inner{width:130px;height:130px;border-radius:50%;background:var(--color-secondary-grouped);display:flex;flex-direction:column;align-items:center;justify-content:center;gap:var(--space-1)}.stats-ring-inner strong{font-size:2rem}.stats-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:var(--space-3)}.stat-card{padding:var(--space-4);border-radius:var(--radius-card);background:var(--color-secondary-grouped);border:.5px solid var(--color-separator);display:flex;flex-direction:column;gap:var(--space-1)}.stat-card strong{font-size:1.5rem}.stat-card--highlight strong{color:var(--color-tint)}.dialog-overlay{position:fixed;top:0;right:0;bottom:0;left:0;background:var(--overlay-bg);display:grid;place-items:center;padding:var(--space-5);z-index:50}.dialog{width:min(560px,100%);background:var(--color-secondary-grouped);border-radius:var(--radius-card);padding:var(--space-5);display:flex;flex-direction:column;gap:var(--space-4)}.import-preview ul{margin:var(--space-2) 0 0;padding-left:var(--space-5)}.dialog--wide{width:min(640px,100%)}.preset-groups{display:flex;flex-direction:column;gap:var(--space-4);margin-bottom:var(--space-4)}.preset-group-title{margin:0 0 var(--space-2);font-size:var(--font-caption);font-weight:600;color:var(--color-label-secondary)}.preset-list{display:flex;flex-direction:column;gap:var(--space-2);max-height:240px;overflow-y:auto}.preset-batch-progress{margin:var(--space-2) 0 0}.card-back-preview{max-width:280px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.preset-option{display:flex;flex-direction:column;align-items:flex-start;gap:var(--space-1);padding:var(--space-3) var(--space-4);border:.5px solid var(--color-separator);border-radius:var(--radius-control);background:var(--color-secondary-grouped);cursor:pointer;text-align:left;width:100%}.preset-option--selected{border-color:var(--color-tint);background:#6366f114}.field-label{display:flex;flex-direction:column;gap:var(--space-2);font-size:var(--font-caption);color:var(--color-label-secondary)}.field-full{width:100%}.dashboard-header .header-actions{flex-shrink:0}.toast-container{position:fixed;right:var(--space-4);bottom:var(--space-4);display:flex;flex-direction:column;gap:var(--space-2);z-index:100}.toast{display:flex;align-items:center;gap:var(--space-3);padding:var(--space-3) var(--space-4);border-radius:var(--radius-control);background:var(--color-secondary-grouped);border:.5px solid var(--color-separator);box-shadow:0 8px 24px #0000001f}.toast--success{border-color:var(--color-green)}.toast--error{border-color:var(--color-red)}.toast-dismiss{border:none;background:transparent;cursor:pointer;font-size:1.25rem;line-height:1}.study-complete{text-align:center;padding:var(--space-8) 0}.study-complete-actions{justify-content:center;margin-top:var(--space-5)}.app-nav{display:flex;align-items:center;gap:var(--space-1)}.app-nav-link{padding:var(--space-2) var(--space-3);border-radius:var(--radius-pill);font-size:var(--font-caption);color:var(--color-label-secondary)}.app-nav-link--active{background:var(--color-gray-fill-secondary);color:var(--color-label);font-weight:600}.learn-hub-header{display:flex;align-items:flex-start;justify-content:space-between;gap:var(--space-4);margin-bottom:var(--space-6)}.learn-hub-settings{display:flex;flex-direction:column;gap:var(--space-2);align-items:flex-end}.learn-hub-limit-input{width:88px;padding:var(--space-2) var(--space-3);border-radius:var(--radius-control);border:.5px solid var(--color-separator);background:var(--color-secondary-grouped)}.learn-hub-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:var(--space-3);margin-bottom:var(--space-5)}.learn-stat-card{display:flex;flex-direction:column;align-items:center;gap:var(--space-2);padding:var(--space-5);border-radius:var(--radius-card);background:var(--color-secondary-grouped);border:.5px solid var(--color-separator)}.learn-stat-card--primary{background:var(--color-tint);color:#fff;border-color:transparent}.learn-stat-card--primary .learn-stat-label{color:#ffffffd9}.learn-stat-value{font-size:2rem;font-weight:700;line-height:1}.learn-stat-label{font-size:var(--font-caption);color:var(--color-label-secondary)}.learn-hub-start{width:100%;min-height:56px;font-size:1.125rem;margin-bottom:var(--space-8)}.learn-hub-empty{text-align:center;padding:var(--space-8) 0}.section-title{font-size:var(--font-title);font-weight:600;margin:0 0 var(--space-4)}.learn-deck-row{display:flex;align-items:center;justify-content:space-between;gap:var(--space-4);padding:var(--space-4);border-radius:var(--radius-card);background:var(--color-secondary-grouped);border:.5px solid var(--color-separator);margin-bottom:var(--space-3)}.learn-deck-title{margin:0 0 var(--space-1);font-weight:600}.btn-disabled{opacity:.45;pointer-events:none}.study-session{min-height:100vh;display:flex;flex-direction:column}.study-session--immersive{background:var(--color-fill);color:var(--color-label)}.study-session-header{position:sticky;top:0;z-index:10;padding:var(--space-3) var(--space-5);background:var(--color-secondary-grouped);border-bottom:.5px solid var(--color-separator)}.study-session-exit{display:inline-block;margin-bottom:var(--space-2);font-size:var(--font-caption);color:var(--color-tint)}.study-session-meta{display:flex;align-items:center;justify-content:space-between;gap:var(--space-3);margin-bottom:var(--space-2)}.study-session-title{font-size:var(--font-caption);color:var(--color-label-secondary)}.study-session-count{font-size:var(--font-caption);font-weight:600}.study-session-progress{height:4px;background:var(--color-gray-fill-secondary);border-radius:var(--radius-pill);overflow:hidden}.study-session-progress-bar{height:100%;background:var(--color-tint);transition:width .2s ease}.study-session-body{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:var(--space-5);max-width:720px;width:100%;margin:0 auto;text-align:center}.study-session-deck{margin:0 0 var(--space-3)}.study-session-loading,.study-session-saving,.study-session-hint{margin-top:var(--space-3)}.study-session-complete{flex:1;display:flex;flex-direction:column;align-items:center;justify-content:center;padding:var(--space-8) var(--space-5);text-align:center}.study-session-stats{list-style:none;padding:0;margin:var(--space-4) 0 var(--space-6);display:flex;gap:var(--space-5);justify-content:center}.flash-card--immersive{min-height:50vh;margin-bottom:var(--space-5)}.flash-card--immersive .flash-card-inner{min-height:50vh}.flash-card--immersive .flash-card-face p{font-size:clamp(1.75rem,5vw,2.5rem)}.flash-card-hint{margin-top:var(--space-4);font-size:var(--font-caption);color:var(--color-label-secondary)}.review-controls--immersive{position:sticky;bottom:0;width:100%;padding:var(--space-3) 0;background:linear-gradient(transparent,var(--color-fill) 24%);overflow-x:auto}.review-btn-label{display:block;font-weight:600}.review-btn-shortcut{display:block;font-size:var(--font-caption);opacity:.85;margin-top:var(--space-1)}.review-btn-interval{display:block;font-size:var(--font-caption);opacity:.9;margin-top:var(--space-1)}.study-session-card-meta{display:flex;align-items:center;justify-content:center;gap:var(--space-3);margin-bottom:var(--space-3)}.study-card-badge{display:inline-block;padding:var(--space-1) var(--space-3);border-radius:var(--radius-pill);font-size:var(--font-caption);font-weight:600}.study-card-badge--new{background:var(--color-tint);color:#fff}.study-card-badge--review{background:var(--color-gray-fill-secondary);color:var(--color-label-secondary)}.learn-hub-empty-actions{display:flex;justify-content:center;gap:var(--space-3);flex-wrap:wrap;margin-top:var(--space-5)}.learn-hub-skeleton-card,.learn-hub-skeleton-button,.learn-hub-skeleton-row{background:var(--color-gray-fill-secondary);animation:learn-hub-pulse 1.2s ease-in-out infinite}.learn-hub-skeleton-card{min-height:96px}.learn-hub-skeleton-button{height:56px;border-radius:var(--radius-control);margin-bottom:var(--space-8)}.learn-hub-skeleton-row{height:72px;border-radius:var(--radius-card);margin-bottom:var(--space-3)}@keyframes learn-hub-pulse{0%,to{opacity:1}50%{opacity:.55}}@media(max-width:720px){.card-form{grid-template-columns:1fr}.list-row{flex-direction:column;align-items:stretch}.dashboard-header,.page-toolbar,.learn-hub-header{flex-direction:column}.learn-hub-stats{grid-template-columns:1fr}.learn-deck-row{flex-direction:column;align-items:stretch}.header-actions{flex-wrap:wrap}}