/* Side navigation: open by default, can slide shut */
:root { --side-w: 15.5rem; --nav-h: 0rem; }
body.opt-b main, body.opt-b .report-footer { margin-left: var(--side-w); --vw: calc(100vw - var(--side-w)); transition: margin-left 0.35s cubic-bezier(0.4, 0, 0.2, 1); }
html { scroll-padding-top: 1rem; }

.side-nav {
  position: fixed; inset: 0 auto 0 0; z-index: 50; width: var(--side-w);
  display: flex; flex-direction: column; overflow-y: auto; scrollbar-width: thin;
  padding: 1.75rem 0 1.5rem; background: var(--navy); color: var(--white); transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1), visibility 0.35s;
}
.side-nav__brand {
  display: block; padding: 0.25rem 3rem 1.4rem 1.4rem; font-family: var(--font-serif); font-weight: 600; font-size: 1.375rem; line-height: 1.1; color: var(--white); text-decoration: none;
}
.side-nav__logo { display: block; margin-top: auto; padding: 2rem 1.4rem 0; }
.side-nav__logo img { display: block; width: 8.5rem; height: auto; }
.side-nav__brand small { margin-top: 0.4rem; display: block; margin-top: 0.4rem; font-family: var(--font-ui); font-size: 0.6875rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; color: var(--sky); }
.side-nav h2 { margin: 1.1rem 0 0.35rem; padding: 0 1.4rem; font-family: var(--font-ui); font-size: 0.6875rem; font-weight: 700; letter-spacing: 0.12em; text-transform: uppercase; color: rgba(217, 239, 250, 0.6); }
.side-nav ul { list-style: none; margin: 0; padding: 0; }
.side-nav li { margin: 0; padding: 0; }
.side-nav .chapter-link {
  display: block; padding: 0.55rem 1.4rem 0.55rem 1.25rem; white-space: normal; border: 0; border-left: 3px solid transparent;
  font-size: 0.8125rem; line-height: 1.3; letter-spacing: 0.04em; color: rgba(255, 255, 255, 0.82);
}
.side-nav .chapter-link:hover { color: var(--white); background: rgba(255, 255, 255, 0.07); }
.side-nav .chapter-link[aria-current="true"] { color: var(--white); background: rgba(255, 255, 255, 0.1); border-left-color: var(--coral); border-bottom-color: transparent; }
.side-nav .report-progress { position: absolute; top: 0; bottom: 0; left: auto; right: 0; width: 3px; height: auto; background: var(--sky-line); transform-origin: 50% 0; transform: scaleY(var(--p, 0)); }
.side-nav__foot { margin-top: 0; padding: 1.1rem 1.4rem 0; font-size: 0.75rem; line-height: 1.4; color: rgba(217, 239, 250, 0.6); }

/* Below ~1230px the page is too narrow for a side panel plus the desktop layouts: fall back to a top bar. */
@media (max-width: 76.99rem) {
  :root { --nav-h: 3.5rem; }
  body.opt-b main, body.opt-b .report-footer { margin-left: 0; --vw: 100vw; }
  html { scroll-padding-top: calc(var(--nav-h) + 1rem); }
  .side-nav { position: sticky; top: 0; inset: auto; width: auto; height: var(--nav-h); flex-direction: row; align-items: center; overflow: auto hidden; padding: 0 0.75rem 0 1rem; }
  .side-nav__brand, .side-nav h2, .side-nav__foot, .side-nav__logo { display: none; }
  .side-nav ul { display: flex; }
  .side-nav .chapter-link { white-space: nowrap; padding: 0.5rem 0.7rem; border-left: 0; border-bottom: 2px solid transparent; }
  .side-nav .chapter-link[aria-current="true"] { background: transparent; border-bottom-color: var(--coral); }
  .side-nav .report-progress { top: auto; bottom: 0; left: 0; right: 0; width: auto; height: 3px; transform-origin: 0 50%; transform: scaleX(var(--p, 0)); }
}

/* Slide the panel shut / bring it back (wide screens only) */
.side-toggle { display: none; }
@media (min-width: 77rem) {
  .side-toggle--close { display: grid; place-items: center; position: absolute; top: 0.9rem; right: 0.75rem; width: 2rem; height: 2rem; padding: 0; border: 0; border-radius: 50%; background: rgba(255, 255, 255, 0.12); color: var(--white); font-size: 1.5rem; line-height: 1; cursor: pointer; transition: background-color 0.15s ease; }
  .side-toggle--close span { transform: translateY(-0.06em); }
  .side-toggle--close:hover { background: rgba(255, 255, 255, 0.24); }
  .side-toggle--open { display: grid; align-content: center; gap: 0.28rem; position: fixed; top: 1rem; left: 1rem; z-index: 60; width: 2.75rem; height: 2.75rem; padding: 0 0.78rem; border: 0; border-radius: 50%; background: var(--navy); box-shadow: 0 4px 14px rgba(5, 36, 96, 0.35); cursor: pointer; opacity: 0; visibility: hidden; transition: opacity 0.3s ease 0.15s, visibility 0.3s 0.15s; }
  .side-toggle--open span { display: block; height: 2px; background: var(--white); border-radius: 1px; }
  html.side-closed .side-nav { transform: translateX(-100%); visibility: hidden; }
  html.side-closed body.opt-b main, html.side-closed body.opt-b .report-footer { margin-left: 0; --vw: 100vw; }
  html.side-closed .side-toggle--open { opacity: 1; visibility: visible; }
}
@media (prefers-reduced-motion: reduce) { .side-nav, body.opt-b main, body.opt-b .report-footer { transition: none; } }