/* v148: compact, accessible category navigation. */
.header .nav{gap:clamp(8px,1.1vw,16px)}
.header .nav > a,.header .nav > details > summary{white-space:nowrap}
.header .nav > .pm-nav-group > summary{
  font-size:clamp(11px,.85vw,13px);font-weight:700;display:flex;align-items:center;gap:4px;
  color:#27304b;cursor:pointer;list-style:none;padding:9px 0;line-height:1.3;
}
.header .nav > .pm-nav-group > summary::-webkit-details-marker{display:none}
.header .nav > .pm-nav-group > summary:hover,.header .nav > .pm-nav-group[open] > summary{color:#6550c8}
.pm-nav-group > summary .pm-nav-symbol{display:inline-block;margin-left:2px;font-size:16px!important;line-height:1.2;transform:none!important}
.pm-nav-group > summary .pm-nav-caret{display:inline-block;margin-left:3px;color:#6653d9;font-size:14px;transition:transform .15s ease}
.pm-nav-group[open] > summary .pm-nav-caret{transform:rotate(180deg)!important}
.pm-nav-group[open] > summary .pm-nav-symbol{transform:none!important}
.header .nav > .pm-nav-group > summary:focus-visible,.pm-special-nav > .pm-nav-group > summary:focus-visible{outline:2px solid #6653d9;outline-offset:4px;border-radius:4px}
.header .nav .pm-nav-group > .pm-nav-panel{
  width:max-content;min-width:230px;max-width:min(310px,calc(100vw - 36px));padding:9px;
  background:#fff;border:1px solid #e5e0f2;border-radius:12px;
  box-shadow:0 16px 38px #17233b24;z-index:100;
}
.header .nav .pm-grade > .pm-nav-panel{left:auto;right:0;min-width:265px}
.header .nav .pm-nav-panel > a{
  display:block;border-radius:8px;padding:11px 12px;color:#27304b;font-size:12px;line-height:1.45;
  font-weight:650;white-space:normal;
}
.header .nav .pm-nav-panel > a:hover,.header .nav .pm-nav-panel > a:focus-visible{background:#f4f0ff;color:#5743bf}
.header .nav .pm-nav-panel > a.pm-nav-practice{color:#5743bf;background:#f6f3ff;font-weight:800}
.header .nav .pm-nav-panel > a.pm-nav-practice:hover{background:#ece7ff}
.header .nav .pm-nav-panel > a.pm-nav-panel-head{font-weight:800}
@media(min-width:901px) and (max-width:1240px){
  .header{padding-left:clamp(14px,2vw,28px);padding-right:clamp(14px,2vw,28px);gap:12px}
  .header .nav{gap:clamp(7px,.85vw,12px)!important}
  .header .nav > a,.header .nav > details > summary{font-size:clamp(10px,.9vw,12px)!important}
  .header .brand-personal strong{font-size:12px;letter-spacing:.06em}
  .header .brand-personal small{font-size:10px}
}
@media(max-width:900px){
  .header .nav > .pm-nav-group{width:100%}
  .header .nav > .pm-nav-group > summary{font-size:15px!important;justify-content:flex-start;white-space:normal;padding:11px 5px}
  .header .nav .pm-nav-group > .pm-nav-panel{position:static;width:100%;min-width:0;max-width:100%;margin:3px 0 6px 2px;padding:3px 0 4px 10px;
     box-shadow:none;border:0;border-left:2px solid #ded8f5;border-radius:0;background:transparent}
  .header .nav .pm-nav-panel > a{font-size:14px;padding:12px 10px;min-height:44px}
  /* Prevent hover-only dropdown behavior on touch: the native details control drives it. */
  .header .nav > .pm-nav-group:not([open]) > .pm-nav-panel{display:none}
  .header .nav > .pm-nav-group[open] > .pm-nav-panel{display:block}
}
/* Legacy custom chapter page: use its narrow original header and no broken blocks. */
.pm-special-nav{gap:clamp(8px,1.15vw,18px)!important;align-items:center}
.pm-special-nav > .pm-nav-group{position:relative;display:inline-block;vertical-align:middle}
.pm-special-nav > .pm-nav-group > summary{list-style:none;cursor:pointer;font-size:12px;font-weight:650;color:inherit;display:flex;gap:5px;align-items:center}
.pm-special-nav > .pm-nav-group > summary::-webkit-details-marker{display:none}
.pm-special-nav > .pm-nav-group > .pm-nav-panel{position:absolute;top:calc(100% + 10px);left:0;display:none;min-width:235px;padding:8px;background:#fff;border:1px solid #e5e0f2;border-radius:10px;box-shadow:0 14px 35px #17233b2a;z-index:100}
.pm-special-nav > .pm-nav-group[open] > .pm-nav-panel,.pm-special-nav > .pm-nav-group:hover > .pm-nav-panel{display:block}
.pm-special-nav .pm-nav-panel a{display:block;color:#17233b;padding:9px;border-radius:6px;font-size:12px;white-space:nowrap}
.pm-special-nav .pm-nav-panel a:hover{background:#f3efff;color:#5846bd}

/* Legacy quantum chapter also gets a usable mobile navigation. */
.pm-special-toggle{display:none;border:0;background:transparent;color:#17233b;font-size:25px;line-height:1;padding:9px;cursor:pointer}
@media(max-width:900px){
 header:has(.pm-special-nav){position:relative;z-index:50}
 .pm-special-toggle{display:block}
 .pm-special-nav{display:none!important;position:absolute;top:72px;left:0;right:0;width:100%;padding:20px;background:#fff;box-shadow:0 16px 30px #17233b23;flex-direction:column;align-items:stretch;gap:17px!important;max-height:calc(100vh - 72px);overflow:auto;z-index:110}
 .pm-special-nav.pm-is-open{display:flex!important}
 .pm-special-nav > .pm-nav-group{display:block;width:100%}
 .pm-special-nav > .pm-nav-group > summary{font-size:14px;min-height:42px}
 .pm-special-nav > .pm-nav-group > .pm-nav-panel{position:static;width:100%;min-width:0;margin:4px 0 6px 2px;border:0;border-left:2px solid #ded8f5;border-radius:0;box-shadow:none;padding:3px 0 3px 9px;background:transparent}
 .pm-special-nav > .pm-nav-group:not([open]) > .pm-nav-panel{display:none}
 .pm-special-nav > .pm-nav-group[open] > .pm-nav-panel{display:block}
 .pm-special-nav .pm-nav-panel a{white-space:normal;min-height:42px;font-size:13px;padding:12px}
}