.bk{--bk-ink: #f2f5ff;--bk-dim: rgba(242, 245, 255, .74);--bk-faint: rgba(242, 245, 255, .3);--bk-night: #060a1c;--bk-mid: #0a2150;--bk-blue: #86cef3;--bk-lit: #0d2c60;--bk-ease: cubic-bezier(.22, 1, .36, 1);position:relative;min-height:100vh;min-height:100svh;display:grid;grid-template-columns:clamp(13rem,17vw,17rem) minmax(0,1fr);color:var(--bk-ink);background:radial-gradient(72% 42% at 50% 105%,#184a8e73,#0d2c6000 68%),linear-gradient(180deg,#01041a,#02061f,#040f2d 48%,#07193d 70%,#0a2350 86%,#0d2c60);font-family:var(--font-aktiv),system-ui,sans-serif;font-weight:300;overflow:hidden}.bk-rule{position:absolute;inset:0 0 auto;height:1px;background:#ffffff1a;z-index:5}.bk-rule i{display:block;height:100%;background:var(--bk-blue);transform-origin:0 50%;transition:transform .7s var(--bk-ease)}.bk-spine{display:flex;flex-direction:column;gap:.15rem;padding:clamp(4.5rem,9vh,7rem) 0 2rem clamp(1.5rem,3vw,3rem);border-right:1px solid rgba(255,255,255,.08);align-content:start}.bk-spine-item{display:flex;align-items:baseline;gap:.75rem;background:none;border:0;border-left:1px solid transparent;padding:.5rem .75rem .5rem .9rem;color:var(--bk-dim);font:inherit;font-size:.9rem;text-align:left;cursor:pointer;transition:color .26s var(--bk-ease),border-color .26s var(--bk-ease)}.bk-spine-item:hover{color:var(--bk-ink)}.bk-spine-item.is-here{color:var(--bk-ink);border-left-color:var(--bk-blue)}.bk-spine-num{font-size:.66rem;letter-spacing:.14em;color:var(--bk-faint)}.bk-spine-item.is-here .bk-spine-num{color:var(--bk-blue)}.bk-brush{position:absolute;top:clamp(1rem,2.4vh,2rem);right:clamp(1rem,2.4vw,2rem);z-index:6;width:min(19rem,calc(100vw - 2rem));border:1px solid rgba(255,255,255,.14);border-radius:14px;background:#041629b8;backdrop-filter:blur(14px)}.bk-brush-tab{display:flex;align-items:center;gap:.6rem;width:100%;padding:.7rem .9rem;background:none;border:0;color:var(--bk-ink);font:inherit;font-size:.78rem;letter-spacing:.02em;cursor:pointer}.bk-brush-mark{width:14px;height:14px;flex:none;border-radius:3px;background-image:radial-gradient(circle at 50% 50%,var(--bk-blue) 40%,transparent 42%);background-size:3.5px 3.5px;opacity:.9}.bk-brush-body{padding:0 .9rem .9rem;display:grid;gap:.7rem}.bk-brush-body[hidden]{display:none}.bk-brush-note{margin:0 0 .2rem;color:var(--bk-dim);font-size:.74rem;line-height:1.5}.bk-brush-modes{display:flex;gap:.3rem}.bk-brush-modes button{flex:1;padding:.42rem 0;background:#ffffff0d;border:1px solid transparent;border-radius:8px;color:var(--bk-dim);font:inherit;font-size:.72rem;cursor:pointer;transition:color .2s var(--bk-ease),background .2s var(--bk-ease)}.bk-brush-modes button[aria-pressed=true]{color:#041629;background:var(--bk-blue)}.bk-brush-slider{display:grid;grid-template-columns:3.6rem 1fr 2.2rem;align-items:center;gap:.5rem;font-size:.72rem;color:var(--bk-dim)}.bk-brush-slider input{width:100%;accent-color:var(--bk-blue)}.bk-brush-slider output{text-align:right;font-variant-numeric:tabular-nums;color:var(--bk-ink)}.bk-brush-reset{justify-self:start;padding:.32rem .7rem;background:none;border:1px solid rgba(255,255,255,.18);border-radius:999px;color:var(--bk-dim);font:inherit;font-size:.7rem;cursor:pointer}.bk-brush-reset:hover{color:var(--bk-ink)}.bk-stage{position:relative;padding:clamp(4.5rem,9vh,7rem) clamp(1.5rem,4vw,4rem) clamp(9rem,18vh,12rem);outline:none;overflow-y:auto}.bk-eyebrow{display:flex;align-items:center;gap:.7rem;margin:0 0 1.1rem;font-family:var(--font-neue-montreal),sans-serif;font-size:.68rem;letter-spacing:.16em;text-transform:uppercase;color:var(--bk-dim)}.bk-eyebrow span{color:var(--bk-blue)}.bk-stage h1{margin:0;max-width:20ch;font-size:clamp(2rem,3.4vw,3.4rem);font-weight:200;letter-spacing:-.035em;line-height:1.02}.bk-contents{max-width:62rem;animation:bk-in .7s var(--bk-ease) both}.bk-lede{margin:1.4rem 0 0;max-width:54ch;color:var(--bk-dim);font-size:clamp(1rem,1.15vw,1.1rem);line-height:1.65}.bk-toc{list-style:none;margin:clamp(2rem,4vh,3rem) 0 0;padding:0;border-top:1px solid rgba(255,255,255,.1)}.bk-toc li{border-bottom:1px solid rgba(255,255,255,.1)}.bk-toc button{display:grid;grid-template-columns:3rem 9rem 1fr;gap:1rem;align-items:baseline;width:100%;padding:1rem .5rem 1rem 0;background:none;border:0;color:var(--bk-ink);font:inherit;text-align:left;cursor:pointer;transition:padding-left .3s var(--bk-ease),background .3s var(--bk-ease)}.bk-toc button:hover{padding-left:.7rem;background:#ffffff0a}.bk-toc-num{font-size:.7rem;letter-spacing:.14em;color:var(--bk-blue)}.bk-toc-name{font-size:1.05rem}.bk-toc-title{color:var(--bk-dim);font-size:.92rem;line-height:1.5}.bk-contents-foot{margin:clamp(2rem,4vh,3rem) 0 0;max-width:46ch;color:var(--bk-dim);font-size:.9rem;line-height:1.6}.bk-spread{display:grid;grid-template-columns:minmax(0,1fr) minmax(16rem,22vw) minmax(0,1fr);grid-template-areas:"head head head" "left picture right" "both both both";gap:clamp(1.5rem,3vw,3rem);align-items:start;max-width:82rem;animation:bk-in .7s var(--bk-ease) both}.bk-head{grid-area:head}.bk-left{grid-area:left}.bk-right{grid-area:right}.bk-picture{grid-area:picture;margin:0;aspect-ratio:1 / 1;border:1px solid rgba(255,255,255,.1);background:#020a14;overflow:hidden}.bk-marks{width:100%;height:100%;display:block}.bk-col-label{margin:0 0 .9rem;font-family:var(--font-neue-montreal),sans-serif;font-size:.62rem;letter-spacing:.16em;text-transform:uppercase;color:var(--bk-faint)}.bk-body{margin:0 0 1rem;max-width:46ch;color:var(--bk-dim);font-size:clamp(.94rem,1.05vw,1.02rem);line-height:1.7}.bk-nature-title{margin:0 0 .7rem;max-width:26ch;font-size:clamp(1.15rem,1.5vw,1.45rem);font-weight:300;letter-spacing:-.02em;line-height:1.2;color:var(--bk-ink)}.bk-both{grid-area:both;display:flex;flex-wrap:wrap;align-items:baseline;gap:.9rem;margin:clamp(.5rem,1.4vh,1.4rem) 0 0;padding-top:1.2rem;border-top:1px solid rgba(255,255,255,.12);font-size:clamp(1.1rem,1.7vw,1.6rem);font-weight:200;letter-spacing:-.02em}.bk-both span{font-family:var(--font-neue-montreal),sans-serif;font-size:.62rem;letter-spacing:.16em;text-transform:uppercase;color:var(--bk-blue)}.bk-term{padding:0;background:none;border:0;border-bottom:1px dotted rgba(134,206,243,.8);color:inherit;font:inherit;cursor:pointer;transition:color .2s var(--bk-ease)}.bk-term:hover{color:var(--bk-blue)}.bk-term-panel{position:fixed;right:clamp(1rem,2.4vw,2rem);bottom:clamp(5rem,11vh,7rem);z-index:8;width:min(24rem,calc(100vw - 2rem));padding:1.1rem 1.2rem 1.2rem;border:1px solid rgba(134,206,243,.35);border-radius:14px;background:#041629f0;backdrop-filter:blur(16px);animation:bk-in .38s var(--bk-ease) both}.bk-term-word{margin:0 0 .5rem;color:var(--bk-blue);font-size:.72rem;letter-spacing:.14em;text-transform:uppercase}.bk-term-meaning{margin:0 0 .9rem;color:var(--bk-dim);font-size:.92rem;line-height:1.65}.bk-term-close{display:inline-flex;gap:.4rem;padding:0;background:none;border:0;color:var(--bk-faint);font:inherit;font-size:.78rem;cursor:pointer}.bk-term-close:hover{color:var(--bk-ink)}.bk-close{max-width:54rem;animation:bk-in .7s var(--bk-ease) both}.bk-close-body{margin-top:1.5rem}.bk-close-body p{margin:0 0 1rem;max-width:52ch;color:var(--bk-dim);font-size:clamp(1rem,1.15vw,1.08rem);line-height:1.7}.bk-close-body strong{color:var(--bk-ink);font-weight:400}.bk-close-links{display:flex;flex-wrap:wrap;gap:1.5rem;align-items:center;margin-top:2rem}.bk-cta,.bk-link{display:inline-flex;align-items:center;gap:.5rem;color:var(--bk-ink);text-decoration:none;font-size:.95rem}.bk-cta{padding:.7rem 1.3rem;border:1px solid var(--bk-blue);border-radius:999px}.bk-cta:hover{background:var(--bk-blue);color:#041629}.bk-link{color:var(--bk-dim);border-bottom:1px solid transparent}.bk-link:hover{color:var(--bk-ink);border-bottom-color:#ffffff59}.bk-turn{position:fixed;right:clamp(1rem,2.4vw,2rem);bottom:clamp(1.1rem,3vh,2rem);z-index:7;display:flex;align-items:center;gap:1.1rem;padding:.45rem .6rem;border:1px solid rgba(255,255,255,.14);border-radius:999px;background:#041629c2;backdrop-filter:blur(14px)}.bk-arrow{width:2.1rem;height:2.1rem;display:grid;place-items:center;background:none;border:0;border-radius:50%;color:var(--bk-ink);font-size:1rem;cursor:pointer;transition:background .22s var(--bk-ease),opacity .22s var(--bk-ease)}.bk-arrow:hover:not(:disabled){background:#ffffff1a}.bk-arrow:disabled{opacity:.28;cursor:default}.bk-count{font-variant-numeric:tabular-nums;font-size:.78rem;letter-spacing:.1em;color:var(--bk-dim)}@keyframes bk-in{0%{opacity:0;transform:translateY(14px)}to{opacity:1;transform:none}}@media (max-width: 1100px){.bk-spread{grid-template-columns:minmax(0,1fr);grid-template-areas:"head" "picture" "left" "right" "both"}.bk-picture{aspect-ratio:4 / 3;max-width:34rem}}@media (max-width: 860px){.bk{grid-template-columns:minmax(0,1fr);overflow:visible}.bk-spine{flex-direction:row;gap:.2rem;overflow-x:auto;padding:1.2rem 1rem .6rem;border-right:0;border-bottom:1px solid rgba(255,255,255,.08);scrollbar-width:none}.bk-spine::-webkit-scrollbar{display:none}.bk-spine-item{flex:none;flex-direction:column;gap:.15rem;padding:.4rem .7rem;border-left:0;border-bottom:1px solid transparent}.bk-spine-item.is-here{border-left-color:transparent;border-bottom-color:var(--bk-blue)}.bk-spine-name{white-space:nowrap}.bk-brush{position:static;width:auto;margin:1rem 1rem 0}.bk-stage{padding-top:1.5rem}.bk-toc button{grid-template-columns:2.4rem 1fr}.bk-toc-title{grid-column:2}.bk-term-panel{left:1rem;right:1rem;width:auto;bottom:5.5rem}.bk-turn{right:50%;transform:translate(50%);bottom:.8rem}}@media (prefers-reduced-motion: reduce){.bk-contents,.bk-spread,.bk-close,.bk-term-panel{animation:none}.bk-rule i{transition:none}}