.nav .wrap.playbook-nav{position:relative;flex-wrap:nowrap;gap:10px;min-height:56px;padding-block:6px}
.nav .chapter-menu{margin-left:auto;flex-shrink:0}
.nav .chapter-menu>summary{display:flex;align-items:center;justify-content:center;gap:8px;min-height:44px;padding:8px 12px;box-sizing:border-box;list-style:none;cursor:pointer;border:1px solid var(--line);border-radius:10px;background:var(--paper);color:var(--ink);font:700 14px/1.3 var(--f-body,system-ui,sans-serif)}
.nav .chapter-menu>summary::-webkit-details-marker{display:none}
.nav .chapter-menu>summary::marker{content:""}
.nav .chapter-menu>summary::after{content:"";width:6px;height:6px;border-right:2px solid currentColor;border-bottom:2px solid currentColor;transform:rotate(45deg);margin-top:-3px}
.nav .chapter-menu[open]>summary::after{transform:rotate(225deg);margin-top:3px}
.nav .chapter-menu>summary:hover,.nav .chapter-menu[open]>summary{background:var(--paper-2)}
.nav .chapter-menu>summary:focus-visible{outline:3px solid var(--ink);outline-offset:3px}
.nav .chapter-menu .navlinks{position:absolute;top:calc(100% + 4px);right:clamp(16px,4vw,40px);display:grid;grid-template-columns:1fr 1fr;gap:4px;width:min(420px,calc(100vw - 32px));max-height:min(65vh,440px);overflow-y:auto;box-sizing:border-box;padding:10px;background:var(--paper);border:1px solid var(--line);border-radius:12px;box-shadow:0 8px 24px rgba(0,0,0,.15)}
.nav .chapter-menu:not([open]) .navlinks{display:none}
.nav .chapter-menu .navlinks a{white-space:normal}
.nav .library-back{margin-left:0;flex-shrink:0}
.nav .brand{min-height:44px;min-width:44px}
html body section[id],html body header[id],html body main [id]{scroll-margin-top:calc(80px + env(safe-area-inset-top,0px))}
@media(max-width:800px){.nav .brand span{display:none}}
@media(max-width:380px){.nav .wrap.playbook-nav{gap:8px}.nav .chapter-menu>summary{font-size:13px;padding-inline:8px}.nav .library-back{font-size:13px;padding-inline:8px}}
@media(prefers-reduced-motion:reduce){.nav .chapter-menu>summary::after{transition:none}}