.bk{padding-bottom:40px}.bk h1{font-family:var(--font-display);letter-spacing:-.02em;margin:0 0 20px;font-size:clamp(38px,5.4vw,64px);line-height:1.05}.bk h3{margin-bottom:10px;font-size:21px}.bk-hero{border:3px solid var(--ink);background:var(--surface);box-shadow:9px 9px 0 var(--ink);border-radius:22px;grid-template-columns:minmax(0,1.1fr) minmax(0,.9fr);align-items:center;gap:40px;margin-block:32px 24px;padding:44px 40px;display:grid}.bk-lead{max-width:520px;color:var(--muted);font-size:18px}.bk-actions{flex-wrap:wrap;align-items:center;gap:18px 26px;margin:28px 0;display:flex}.bk-toc{flex-wrap:wrap;gap:10px;display:flex}.bk-toc a{border:2px solid var(--ink);background:var(--canvas);min-height:36px;color:var(--ink);box-shadow:2px 2px 0 var(--ink);border-radius:999px;align-items:center;padding:4px 14px;font-size:13px;font-weight:700;text-decoration:none;transition:transform .15s,box-shadow .15s;display:inline-flex}.bk-toc a:hover{box-shadow:3px 3px 0 var(--ink);background:var(--yellow);transform:translate(-1px,-1px)}.illus-wrap-brand{width:100%;max-width:440px;margin-inline:auto}.illus-brand{width:100%;height:auto;display:block}.bk-card{border:3px solid var(--ink);background:var(--surface);box-shadow:5px 5px 0 var(--ink);border-radius:22px;padding:26px}.bk-card>p:last-child{margin-bottom:0}.bk-note{color:var(--muted);font-size:14px}.bk-subtitle{margin:44px 0 18px}.bk-split{grid-template-columns:1fr 1fr;gap:24px;margin-top:24px;display:grid}.bk-traits{grid-template-columns:repeat(4,1fr);gap:20px;margin-bottom:24px;display:grid}.bk-traits p{color:var(--muted)}.bk-dot{border:3px solid var(--ink);width:34px;height:34px;box-shadow:3px 3px 0 var(--ink);border-radius:10px;margin-bottom:16px;display:block;transform:rotate(-5deg)}.bk-voice table{border-collapse:collapse;width:100%}.bk-voice th,.bk-voice td{text-align:left;vertical-align:top;border-bottom:2px dashed var(--line);padding:12px 10px}.bk-voice td svg{vertical-align:-3px;margin-right:6px}.bk-voice td:first-child{font-weight:800}.bk-voice td:last-child{color:var(--muted)}.bk-tag{border:2px solid var(--ink);letter-spacing:.08em;border-radius:999px;padding:2px 10px;font-size:12px;font-weight:800;display:inline-block}.bk-tag-yes{background:var(--mint)}.bk-tag-no{background:var(--canvas)}.bk-anatomy{background:var(--canvas);grid-template-columns:1.2fr 1fr;align-items:center;gap:32px;display:grid}.bk-anatomy img{width:100%;height:auto}.bk-anatomy ol{margin:0;padding-left:22px}.bk-anatomy li+li{margin-top:8px}.bk-versions{grid-template-columns:repeat(3,1fr);gap:20px;display:grid}.bk-version{margin:0}.bk-version-stage{aspect-ratio:16/9;border:3px solid var(--ink);box-shadow:4px 4px 0 var(--ink);background:var(--surface);border-radius:18px;place-items:center;padding:28px;display:grid}.bk-version-stage img{width:100%;height:auto}.bk-version figcaption,.bk-dont figcaption{margin-top:12px;font-size:14px;font-weight:600}.bk-icon-sizes{background:var(--canvas);justify-content:center;align-items:flex-end;gap:18px;display:flex}.bk-icon-sizes span{justify-items:center;gap:6px;display:grid}.bk-icon-sizes img{width:auto}.bk-icon-sizes small{font-size:11px;font-weight:700}.bk-clearspace{border:2px dashed var(--ink);background:repeating-linear-gradient(-45deg,#0000 0 8px,#ff9fcf40 8px 16px);border-radius:12px;margin-top:20px;padding:34px;position:relative}.bk-clearspace img{background:var(--canvas);outline:2px solid var(--ink);width:100%;height:auto;display:block}.bk-x{font-size:13px;font-style:italic;font-weight:800;position:absolute}.bk-x-top{top:8px;left:50%}.bk-x-left{top:50%;left:12px;transform:translateY(-50%)}.bk-sizes{gap:16px;margin:0 0 16px;display:grid}.bk-sizes div{border:2px solid var(--ink);background:var(--canvas);border-radius:14px;padding:14px 16px}.bk-sizes dt{font-weight:800}.bk-sizes dd{margin:0}.bk-donts{grid-template-columns:repeat(3,1fr);gap:20px;display:grid}.bk-dont{margin:0}.bk-dont-stage{aspect-ratio:16/9;border:3px solid var(--ink);background:var(--canvas);border-radius:18px;place-items:center;padding:28px;display:grid;position:relative;overflow:hidden}.bk-dont-stage img{width:100%;height:auto}.bk-dont-mark{border:2px solid var(--ink);background:var(--orange);width:32px;height:32px;box-shadow:2px 2px 0 var(--ink);border-radius:50%;place-items:center;display:grid;position:absolute;top:10px;right:10px}.bk-dont-stretch img{width:80%;transform:scale(1.2,.6)}.bk-dont-recolor img{filter:hue-rotate(150deg)saturate(1.4)}.bk-dont-rotate img{width:80%;transform:rotate(-18deg)}.bk-dont-font span{font-family:Georgia,Times New Roman,serif;font-size:clamp(24px,3vw,34px);font-style:italic}.bk-dont-busy{background:repeating-linear-gradient(45deg, var(--pink) 0 14px, var(--yellow) 14px 28px, var(--mint) 28px 42px)}.bk-dont-split{grid-auto-flow:column;gap:10px}.bk-dont-split img:first-child{clip-path:inset(0 0 0 20%);width:78%}.bk-dont-split img:last-child{width:44px}.bk-palette{grid-template-columns:repeat(7,1fr);gap:14px;margin:0 0 24px;padding:0;list-style:none;display:grid}.bk-swatch{border:3px solid var(--ink);background:var(--surface);box-shadow:4px 4px 0 var(--ink);border-radius:18px;align-content:start;gap:2px;padding:12px 12px 16px;font-size:12px;display:grid}.bk-swatch-chip{border:2px solid var(--ink);border-radius:12px;height:84px;margin-bottom:10px}.bk-swatch strong{font-size:15px;line-height:1.25}.bk-swatch code{font-size:14px;font-weight:800}.bk-swatch em{color:var(--muted);margin-top:6px;font-style:normal}.bk-share-bar{border:3px solid var(--ink);border-radius:999px;height:44px;display:flex;overflow:hidden}.bk-share-bar span+span{border-left:3px solid var(--ink)}.bk-share-legend{flex-wrap:wrap;gap:8px 22px;margin:14px 0 0;padding:0;font-size:14px;font-weight:700;list-style:none;display:flex}.bk-share-legend span{vertical-align:-2px;border:2px solid var(--ink);border-radius:4px;width:14px;height:14px;margin-right:8px;display:inline-block}.bk-contrast{grid-template-columns:repeat(3,1fr);gap:12px;margin:0;padding:0;list-style:none;display:grid}.bk-contrast li{border:3px solid var(--ink);border-radius:14px;gap:4px;padding:12px;font-size:12px;font-weight:700;line-height:1.35;display:grid}.bk-contrast b{font-family:var(--font-display);font-size:30px;line-height:1}.bk-contrast-fail{text-shadow:0 0 1px var(--ink)}.bk-type{gap:4px;margin-bottom:16px;display:grid}.bk-type-row{border-bottom:2px dashed var(--line);grid-template-columns:220px 1fr;align-items:baseline;gap:24px;padding:14px 0;display:grid}.bk-type-row:last-child{border-bottom:0}.bk-type-role{color:var(--muted);font-size:12px;font-weight:700}.bk-type-display,.bk-type-h1,.bk-type-h2{font-family:var(--font-display);letter-spacing:-.02em}.bk-type-display{font-size:clamp(36px,5vw,56px);line-height:1.05}.bk-type-h1{font-size:clamp(28px,3.4vw,36px);line-height:1.1}.bk-type-h2{font-size:24px;line-height:1.2}.bk-type-h3{font-size:18px;font-weight:700;line-height:1.3}.bk-type-body{font-size:16px;line-height:1.5}.bk-type-label,.bk-label{letter-spacing:.08em;font-size:12px;font-weight:700}.bk-elements{grid-template-columns:repeat(4,1fr);gap:20px;margin-bottom:24px;display:grid}.bk-elements p{color:var(--muted)}.bk-el-demo{background:var(--canvas);border-radius:14px;height:92px;margin-bottom:18px}.bk-el-shadow{border:3px solid var(--ink);background:var(--yellow);width:70%;box-shadow:6px 6px 0 var(--ink)}.bk-el-line{background:linear-gradient(var(--ink), var(--ink)) 12px 30px / calc(100% - 24px) 2px no-repeat, linear-gradient(var(--ink), var(--ink)) 12px 58px / calc(100% - 24px) 3px no-repeat, var(--canvas)}.bk-el-radius{border:3px solid var(--ink);background:var(--pink);border-radius:30px 14px 22px 999px}.bk-el-dots{border:3px solid var(--ink);background-color:var(--surface);background-image:radial-gradient(#1e1b1821 2px,#0000 2.5px);background-size:22px 22px}.bk-components{flex-wrap:wrap;align-items:flex-start;gap:28px 48px;display:flex}.bk-row{flex-wrap:wrap;align-items:center;gap:12px;display:flex}.bk-btn{border:3px solid var(--ink);background:var(--surface);min-height:48px;box-shadow:4px 4px 0 var(--ink);border-radius:14px;align-items:center;padding:0 22px;font-weight:800;display:inline-flex}.bk-btn-primary{background:var(--yellow);font-family:var(--font-display);font-weight:400}.bk-btn-pressed{box-shadow:1px 1px 0 var(--ink);transform:translate(3px,3px)}.bk-chip{border:2px solid var(--ink);background:var(--surface);letter-spacing:.06em;box-shadow:2px 2px 0 var(--ink);border-radius:999px;padding:4px 12px;font-size:12px;font-weight:800;display:inline-block}.bk-chip-tilt{background:var(--yellow);transform:rotate(-5deg)}.bk-countdown{border:3px solid var(--ink);background:var(--yellow);width:72px;height:72px;font-family:var(--font-display);box-shadow:4px 4px 0 var(--ink);border-radius:50%;place-items:center;font-size:40px;display:grid}.bk-illus{grid-template-columns:1fr 1fr 1fr;align-items:stretch;gap:20px;display:grid}.bk-illus-art{background:var(--canvas);place-items:center;display:grid}.bk-illus-art .illus-wrap-usecase{margin:0}.bk-illus-art .illus-wrap-invite{width:min(260px,90%);margin:0}.bk-rules{margin:0;padding:24px 24px 24px 44px}.bk-rules li+li{margin-top:10px}.bk-download{border:3px solid var(--ink);background:var(--yellow);box-shadow:9px 9px 0 var(--ink);border-radius:22px;grid-template-columns:1fr 1fr;gap:36px;padding:40px;display:grid;position:relative}.bk-download-burst{width:min(360px,100%);height:360px;top:-60px;left:0}.bk-download-copy{position:relative}.bk-download h2{letter-spacing:-.02em;margin-bottom:14px}.bk-download-copy .button-primary{background:var(--surface);margin:8px 0 18px}.bk-download-copy .bk-note{color:var(--ink)}.bk-download-copy .bk-note a{font-weight:700}.bk-download-copy .bk-note svg{vertical-align:-2px}.bk-files{border:3px solid var(--ink);background:var(--surface);border-radius:18px;gap:10px;margin:0;padding:20px;display:grid;position:relative}.bk-files div{grid-template-columns:120px 1fr;gap:12px;font-size:14px;display:grid}.bk-files dt{font-weight:800}.bk-files dd{color:var(--muted);margin:0}.bk-usage{margin-top:24px}@media (max-width:1000px){.bk-palette{grid-template-columns:repeat(4,1fr)}.bk-traits,.bk-elements{grid-template-columns:repeat(2,1fr)}.bk-illus{grid-template-columns:1fr 1fr}.bk-illus .bk-rules{grid-column:1/-1}}@media (max-width:760px){.bk-hero,.bk-anatomy,.bk-split,.bk-download,.bk-illus{grid-template-columns:1fr}.bk-hero{box-shadow:6px 6px 0 var(--ink);padding:28px 18px}.bk-download{box-shadow:6px 6px 0 var(--ink);padding:26px 18px}.bk-versions,.bk-donts,.bk-palette,.bk-contrast{grid-template-columns:repeat(2,1fr)}.bk-traits,.bk-elements{grid-template-columns:1fr}.bk-type-row{grid-template-columns:1fr;gap:6px}.bk-files div{grid-template-columns:1fr;gap:2px}}@media (prefers-reduced-motion:reduce){.bk-toc a{transition:none}}