:root{color-scheme:light;--color-canvas: #ffffff;--color-canvas-deep: #f0f0f0;--color-surface: #ffffff;--color-surface-muted: #f4f4f4;--color-sidebar: #f9f9f9;--color-sidebar-hover: rgb(0 0 0 / .05);--color-sidebar-active: rgb(0 0 0 / .08);--color-ink: #0d0d0d;--color-brand-ink: #0d0d0d;--color-ink-soft: #5d5d5d;--color-ink-muted: #6e6e6e;--color-border: rgb(0 0 0 / .1);--color-surface-lift: rgb(255 255 255 / .55);--color-border-strong: rgb(0 0 0 / .16);--color-accent: #4255ff;--color-accent-strong: #423ed8;--color-accent-soft: #eef0ff;--color-accent-contrast: #ffffff;--color-accent-overlay: rgb(255 255 255 / .2);--color-success: #0b7f59;--color-success-soft: #e6f7f0;--color-warning: #ffcd1f;--color-star: #f59e0b;--color-highlight: #efe7fd;--color-highlight-ink: #4c1d95;--color-warning-ink: #7c6200;--color-warning-soft: #fff7da;--color-danger: #c7253f;--color-danger-soft: #ffeef0;--color-google-button: #ffffff;--color-google-button-hover: #f5f5f5;--color-google-button-ink: #1f1f1f;--color-overlay: rgb(13 13 13 / .56);--color-focus: rgb(66 85 255 / .22);--color-transparent: transparent;--font-body: ui-sans-serif, -apple-system, BlinkMacSystemFont, "system-ui", Pretendard, "Apple SD Gothic Neo", "Segoe UI", "Noto Sans KR", Helvetica, Arial, sans-serif;--font-display: var(--font-body);--font-google: Roboto, Arial, sans-serif;--font-mono: "SFMono-Regular", Consolas, monospace;--text-2xs: .625rem;--text-xs: .75rem;--text-sm: .875rem;--text-base: 1rem;--text-navigation: 1.0625rem;--text-md: 1.125rem;--text-lg: 1.25rem;--text-xl: 1.5rem;--text-display: clamp(1.75rem, 4vw, 2.25rem);--type-page-size: var(--text-xl);--type-page-weight: var(--weight-semibold);--type-navigation-size: var(--text-navigation);--type-navigation-weight: var(--weight-semibold);--type-section-size: var(--text-lg);--type-section-weight: var(--weight-semibold);--type-item-size: var(--text-base);--type-item-weight: var(--weight-medium);--type-body-size: var(--text-sm);--type-body-weight: var(--weight-regular);--type-meta-size: var(--text-xs);--type-meta-weight: var(--weight-regular);--weight-regular: 400;--weight-medium: 500;--weight-semibold: 600;--leading-tight: 1.25;--leading-snug: 1.4;--leading-body: 1.5;--space-1: .25rem;--space-2: .5rem;--space-3: .75rem;--space-4: 1rem;--space-5: 1.25rem;--space-6: 1.5rem;--space-7: 2rem;--space-8: 2.5rem;--space-9: 3rem;--space-10: 4rem;--space-11: 5rem;--question-figure-max-height: 20rem;--radius-xs: .375rem;--radius-sm: .5rem;--radius-md: .75rem;--radius-lg: 1rem;--radius-pill: 999rem;--stroke: .0625rem;--stroke-strong: .125rem;--shadow-soft: 0 .0625rem .1875rem rgb(13 13 13 / .1);--shadow-floating: 0 .75rem 2rem rgb(13 13 13 / .12);--shadow-popover: 0 .25rem .75rem rgb(13 13 13 / .14), 0 .0625rem .1875rem rgb(13 13 13 / .1);--term-popover-arrow-left: 50%;--shadow-top: 0 -.5rem 1.5rem rgb(13 13 13 / .05);--ring-hairline: 0 0 0 var(--stroke) var(--color-border);--focus-ring: var(--stroke-strong) solid var(--color-accent);--motion-instant: 1ms;--motion-quick: .12s;--motion-base: .16s;--motion-slow: .22s;--sidebar-width: 16.25rem;--sidebar-collapsed-width: 3.5rem;--content-width: 63.75rem;--reading-width: 52rem;--thumbnail-width: 7rem;--page-thumbnail-width: 20rem;--document-cover-min-width: 13rem;--folder-cover-min-width: 15rem;--folder-preview-width: 42%;--folder-preview-max-height: 7.75rem;--folder-preview-angle-start: -3deg;--folder-preview-angle-middle: 2deg;--folder-preview-angle-end: 5deg;--linked-document-max-width: 14rem;--set-card-min-width: 17.5rem;--set-card-min-height: 13rem;--action-menu-min-width: 12rem;--control-height-xs: 1.8rem;--control-height-sm: 2.75rem;--control-height: 2.75rem;--control-height-lg: 3.15rem;--tap-target: 2.75rem;--navigation-header-side-width: calc(var(--tap-target) + var(--tap-target) + var(--space-1));--icon-sm: 1rem;--icon-md: 1.2rem;--icon-lg: 1.6rem;--safe-area-top: env(safe-area-inset-top, 0px);--safe-area-bottom: env(safe-area-inset-bottom, 0px);--color-bar: var(--color-surface);--bottom-nav-height: calc(var(--control-height-lg) + var(--safe-area-bottom));--layer-quiz-focus: 25;--layer-menu: 40}@media(prefers-color-scheme:dark){:root{color-scheme:dark;--color-canvas: #212121;--color-canvas-deep: #2f2f2f;--color-surface: #2a2a2a;--color-surface-muted: #303030;--color-sidebar: #171717;--color-sidebar-hover: rgb(255 255 255 / .08);--color-sidebar-active: rgb(255 255 255 / .13);--color-ink: #ffffff;--color-brand-ink: #ffffff;--color-ink-soft: #cdcdcd;--color-ink-muted: #afafaf;--color-border: rgb(255 255 255 / .13);--color-surface-lift: rgb(255 255 255 / .08);--color-border-strong: rgb(255 255 255 / .22);--color-accent: #7c89ff;--color-accent-strong: #aab2ff;--color-accent-soft: #2c3163;--color-accent-contrast: #0d0d0d;--color-accent-overlay: rgb(0 0 0 / .16);--color-success: #57d7aa;--color-success-soft: #173a31;--color-warning: #ffd95e;--color-star: #fbbf24;--color-highlight: #443068;--color-highlight-ink: #f0e9ff;--color-warning-ink: #ffe797;--color-warning-soft: #3a3218;--color-danger: #ff7d8d;--color-danger-soft: #482129;--color-overlay: rgb(0 0 0 / .72);--color-focus: rgb(124 137 255 / .32);--shadow-soft: 0 .125rem .5rem rgb(0 0 0 / .24);--shadow-floating: 0 .75rem 2rem rgb(0 0 0 / .4);--shadow-popover: 0 .25rem .75rem rgb(0 0 0 / .45), 0 .0625rem .1875rem rgb(0 0 0 / .35);--shadow-top: 0 -.5rem 1.5rem rgb(0 0 0 / .24)}}@media(prefers-contrast:more){:root{--color-ink-soft: var(--color-ink);--color-ink-muted: var(--color-ink-soft);--color-border: var(--color-border-strong);--stroke: .09375rem}}*{box-sizing:border-box}html{background:var(--color-canvas);color:var(--color-ink);font-family:var(--font-body);scroll-behavior:smooth}body{margin:0;min-width:0;min-height:100vh;min-height:100dvh;background:var(--color-canvas);color:var(--color-ink);font-size:var(--text-base);line-height:var(--leading-body);text-rendering:optimizeLegibility;word-break:keep-all;overflow-wrap:break-word}button,input,textarea,select{color:inherit;font:inherit}button,summary,select{cursor:pointer}button:disabled,select:disabled,input:disabled,textarea:disabled{cursor:not-allowed}a{color:inherit;text-decoration:none}img,svg{display:block}h1,h2,h3,h4,h5,h6,p,dl,dd,ol{margin:0}h1,h2,h3,h4,h5,h6,strong,b,th{font-weight:var(--weight-semibold)}:focus-visible{outline:var(--stroke-strong) solid var(--color-accent);outline-offset:var(--space-1);box-shadow:0 0 0 var(--space-1) var(--color-focus)}::selection{background:var(--color-accent-soft)}.visually-hidden{position:absolute;width:var(--stroke);height:var(--stroke);padding:0;margin:calc(var(--stroke) * -1);overflow:hidden;clip:rect(0 0 0 0);white-space:nowrap;border:0}.brand{display:inline-flex;align-items:center;gap:var(--space-2);font-weight:var(--weight-semibold);letter-spacing:-.03125rem}.brand__mark{width:var(--icon-lg);height:var(--icon-lg);flex:0 0 var(--icon-lg)}.brand__word{color:var(--color-accent);font-size:var(--text-lg)}.brand__word span{color:var(--color-brand-ink)}.brand--compact{gap:var(--space-1)}.brand--compact .brand__mark{width:var(--icon-md);height:var(--icon-md);flex-basis:var(--icon-md)}.brand--compact .brand__word{font-size:var(--text-md)}.standalone-state{display:grid;min-height:100vh;place-content:center;gap:var(--space-6);padding:var(--space-7)}.standalone-state>.brand{justify-self:center}.ui-button{display:inline-flex;min-height:var(--control-height);align-items:center;justify-content:center;gap:var(--space-2);padding:0 var(--space-4);border:var(--stroke) solid var(--color-transparent);border-radius:var(--radius-pill);background:var(--color-accent);color:var(--color-surface);font-size:var(--text-sm);font-weight:var(--weight-medium);line-height:1;transition:transform .12s ease,background-color .16s ease,border-color .16s ease}.ui-button svg{width:var(--icon-sm);height:var(--icon-sm)}.ui-button:hover{background:var(--color-accent-strong)}.ui-button:active{transform:translateY(var(--stroke))}.ui-button:disabled{opacity:.48}.ui-button--secondary{border-color:var(--color-transparent);background:var(--color-surface-muted);color:var(--color-ink)}.ui-button--secondary:hover{border-color:var(--color-transparent);background:var(--color-accent-soft)}.ui-button--ghost{border-color:var(--color-transparent);background:var(--color-transparent);color:var(--color-ink-soft)}.ui-button--ghost:hover{background:var(--color-surface-muted);color:var(--color-ink)}.ui-button--danger{border-color:var(--color-danger-soft);background:var(--color-danger-soft);color:var(--color-danger)}.ui-button--danger:hover{border-color:var(--color-danger);background:var(--color-danger);color:var(--color-surface)}.ui-button--google{width:100%;border:var(--stroke) solid var(--color-border-strong);border-radius:var(--radius-pill);background:var(--color-google-button);color:var(--color-google-button-ink);font-family:var(--font-google);box-shadow:none}.ui-button--google:hover{background:var(--color-google-button-hover)}.ui-button--xs{min-height:var(--tap-target);padding:0 var(--space-3);font-size:var(--text-xs)}.ui-button--sm{min-height:2.25rem;padding:0 var(--space-3)}.ui-button--lg{min-height:var(--control-height-lg);padding:0 var(--space-6);font-size:var(--text-base)}.ui-button--icon{width:var(--tap-target);min-width:var(--tap-target);min-height:var(--tap-target);padding:0}@keyframes ui-popover-in{0%{opacity:0;scale:.96}to{opacity:1;scale:1}}@keyframes ui-popover-out{0%{opacity:1;scale:1}to{opacity:0;scale:.98}}.ui-state{display:flex;min-height:12rem;flex-direction:column;align-items:center;justify-content:center;gap:var(--space-3);padding:var(--space-8);border:0;border-radius:var(--radius-lg);background:var(--color-transparent);color:var(--color-ink-muted);text-align:center}.ui-state__icon{width:var(--space-9);height:var(--space-9);color:var(--color-accent)}.ui-state h3{color:var(--color-ink);font-family:var(--font-display);font-size:var(--text-lg)}.ui-state p{max-width:var(--reading-width);margin-top:var(--space-1);font-size:var(--text-sm)}.ui-state__action{margin-top:var(--space-3)}.ui-error{display:flex;align-items:flex-start;gap:var(--space-3);padding:var(--space-4);border:0;border-radius:var(--radius-md);background:var(--color-danger-soft);color:var(--color-danger);font-size:var(--text-sm)}.ui-error>svg{flex:0 0 var(--icon-md);width:var(--icon-md);height:var(--icon-md);margin-top:var(--space-1)}.ui-error__copy{display:flex;flex:1;flex-direction:column}.ui-error .ui-button{margin-left:auto}.ui-skeleton{display:block;width:100%;height:var(--space-4);overflow:hidden;border-radius:var(--radius-xs);background:var(--color-border);animation:pulse 1.6s ease-in-out infinite}.ui-skeleton--short{width:58%}.ui-skeleton--thumbnail{width:var(--thumbnail-width);height:calc(var(--thumbnail-width) * 1.33)}@keyframes pulse{50%{opacity:.45}}.key-point__mark{padding:0 .125rem;border-radius:var(--radius-xs);background:var(--color-highlight);color:var(--color-highlight-ink);font-weight:var(--weight-semibold)}.landing{--landing-width: 64rem;--landing-header-height: 4.5rem;display:flex;min-height:100vh;flex-direction:column;align-items:center;gap:0;padding:0 var(--space-6) var(--space-11);background:var(--color-canvas)}.landing-top{display:grid;width:min(100%,var(--landing-width));align-items:center;gap:var(--space-8);padding-top:var(--space-9);grid-template-columns:minmax(0,1fr) minmax(0,1.15fr)}.landing-hero{display:flex;flex-direction:column;align-items:center;gap:var(--space-5);text-align:center;justify-content:center;width:100%;padding-block:var(--space-9) var(--space-8)}.landing-header{width:min(100%,var(--landing-width));min-height:var(--landing-header-height);display:flex;align-items:center;justify-content:space-between;gap:var(--space-4)}.landing-header>a{text-decoration:none}.landing-header nav{display:flex;align-items:center;gap:var(--space-6)}.landing-header nav>a{font-size:var(--text-sm);color:var(--color-ink-soft);text-decoration:none}.landing-footer{display:flex;flex-wrap:wrap;justify-content:center;gap:var(--space-5);margin-top:var(--space-10);font-size:var(--text-sm);color:var(--color-ink-muted)}.landing-hero__brand{margin-bottom:var(--space-2)}.landing-hero__title{font-family:var(--font-display);font-size:var(--text-display);font-weight:var(--weight-semibold);letter-spacing:-.0375rem;line-height:var(--leading-tight)}.landing-hero__lede{color:var(--color-ink-soft);font-size:var(--text-md);line-height:var(--leading-body)}.landing-cta{display:flex;width:min(100%,22rem);flex-direction:column;gap:var(--space-3);margin-top:var(--space-2)}.landing-hero__note{color:var(--color-ink-muted);font-size:var(--text-sm)}.landing-demo{display:flex;min-width:0;flex-direction:column;gap:var(--space-3)}.landing-demo__frame{width:100%;overflow:hidden;border:var(--stroke) solid var(--color-border);border-radius:var(--radius-lg);background:var(--color-surface);box-shadow:var(--shadow-floating)}.landing-demo__video{display:block;width:100%;height:auto}.landing-list{display:flex;width:min(100%,var(--landing-width));flex-direction:column;gap:var(--space-6)}.landing-list__title{font-family:var(--font-display);font-size:var(--text-xl);font-weight:var(--weight-semibold)}.landing-list__items{display:flex;flex-direction:column;margin:0;padding:0;list-style:none}.landing-item{display:flex;gap:var(--space-5);padding:var(--space-6) 0;border-top:var(--stroke) solid var(--color-border)}.landing-item__number{flex:0 0 2.5rem;color:var(--color-ink-muted);font-size:var(--text-sm);font-weight:var(--weight-semibold);letter-spacing:.08em}.landing-item__copy{display:flex;min-width:0;flex-direction:column;gap:var(--space-2);max-width:var(--reading-width)}.landing-item h3{display:flex;align-items:center;gap:var(--space-2);font-family:var(--font-display);font-size:var(--text-md);font-weight:var(--weight-semibold)}.landing-item h3 svg{width:var(--icon-md);height:var(--icon-md);color:var(--color-accent)}.landing-item p{color:var(--color-ink-soft);line-height:var(--leading-body)}.landing-close{display:flex;width:min(100%,var(--landing-width));flex-direction:column;align-items:center;gap:var(--space-3);padding-top:var(--space-9);border-top:var(--stroke) solid var(--color-border);text-align:center}.landing-close h2{font-family:var(--font-display);font-size:var(--text-xl);font-weight:var(--weight-semibold)}.landing-close p{color:var(--color-ink-soft)}@keyframes quiz-card-leave-forward{to{opacity:0;transform:translate(calc(var(--space-8) * -1))}}@keyframes quiz-card-enter-forward{0%{opacity:0;transform:translate(var(--space-8))}}@keyframes quiz-card-leave-backward{to{opacity:0;transform:translate(var(--space-8))}}@keyframes quiz-card-enter-backward{0%{opacity:0;transform:translate(calc(var(--space-8) * -1))}}@media(max-width:52rem){:root{--text-base: 1rem}.landing{padding:0 var(--space-4) var(--space-9)}.landing-header nav{gap:var(--space-3)}.landing-hero__title{font-size:var(--text-xl)}.landing-top{grid-template-columns:minmax(0,1fr)}.landing-item{flex-direction:column;gap:var(--space-2)}}@media(max-width:38rem){:root{--document-cover-min-width: 8rem;--folder-cover-min-width: 9rem}}@media(prefers-reduced-motion:reduce){html{scroll-behavior:auto}.ui-skeleton{animation:none}.ui-button{transition-duration:var(--motion-instant)}}@keyframes lecture-pulse{0%,to{opacity:1}50%{opacity:.25}}.ui-skeleton-list{display:flex;flex-direction:column;gap:var(--space-5)}.ui-skeleton-row{display:grid;gap:var(--space-4);grid-template-columns:auto 1fr;align-items:center}.ui-skeleton-row__thumb{width:var(--thumbnail-width);height:calc(var(--thumbnail-width) * 1.33);border-radius:var(--radius-sm)}.ui-skeleton-row__body{display:flex;flex-direction:column;gap:var(--space-3);min-width:0}.ui-skeleton-card{display:flex;flex-direction:column;gap:var(--space-3)}.ui-skeleton-card__cover{height:auto;aspect-ratio:var(--cover-aspect-ratio);border-radius:var(--radius-md)}html,body{overflow-x:clip}.landing-steps{display:flex;flex-direction:column;gap:var(--space-10)}.landing-step{display:flex;flex-direction:column;align-items:center;text-align:center}.landing-step h2{margin:0 0 var(--space-3);color:var(--color-ink);font-size:var(--text-xl);font-weight:var(--weight-semibold);line-height:1.4}.landing-step p{margin:0 0 var(--space-5);color:var(--color-ink-soft);font-size:var(--text-base);line-height:1.7}.landing-step__frame{overflow:hidden;width:min(100%,46rem);border:var(--stroke) solid var(--color-border);border-radius:var(--radius-lg);box-shadow:var(--shadow-soft)}.landing-step__video{display:block;width:100%}.landing .key-point__mark{background:var(--color-accent-soft);color:var(--color-accent-strong)}