/* system.css — header, navigation, mobile sheet, footer */

.page-top {
  position: sticky;
  top: 0;
  z-index: 999;
  background: var(--color-paper);
  border-bottom: 1px solid var(--color-line);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding-block: 14px;
}

.site-name {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--ff-display);
  font-weight: 600;
  font-size: 1.32rem;
  color: var(--color-deep);
  letter-spacing: -0.01em;
}
.site-name:hover { text-decoration: none; }
.site-name .mark {
  width: 30px; height: 30px;
  flex: none;
}
.site-name .mark svg { width: 100%; height: 100%; display: block; }

.main-nav { display: none; }

.nav-list {
  list-style: none;
  display: flex;
  align-items: center;
  gap: 26px;
  margin: 0;
  padding: 0;
}
.nav-list a {
  color: var(--color-ink);
  font-weight: 500;
  font-size: .98rem;
  padding-block: 6px;
}
.nav-list a:hover { color: var(--color-primary); text-decoration: none; }
.nav-list a[aria-current="page"] { color: var(--color-primary); border-bottom: 2px solid var(--color-accent); }

.header-cta { display: none; }

.nav-toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 48px; height: 48px;
  padding: 12px;
  background: transparent;
  border: 1px solid var(--color-line);
  border-radius: var(--radius-s);
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--color-deep);
  border-radius: 2px;
  transition: transform .25s var(--ease), opacity .2s var(--ease);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* mobile fullscreen sheet — solid bg, z above header */
.nav-sheet {
  position: fixed;
  inset: 0;
  z-index: 1100;
  background: var(--color-deep);
  color: #fff;
  padding: 88px 28px 40px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transform: translateX(100%);
  transition: transform .32s var(--ease);
  overflow-y: auto;
}
.nav-sheet.is-open { transform: translateX(0); }
.nav-sheet a {
  color: #fff;
  font-family: var(--ff-display);
  font-size: 1.5rem;
  padding: 14px 4px;
  border-bottom: 1px solid rgba(255,255,255,.12);
}
.nav-sheet a:hover { color: var(--color-accent); text-decoration: none; }
.nav-sheet .sheet-cta { margin-top: 24px; }
.sheet-close {
  position: absolute;
  top: 24px; right: 24px;
  width: 48px; height: 48px;
  background: transparent;
  border: 1px solid rgba(255,255,255,.35);
  border-radius: var(--radius-s);
  color: #fff;
  font-size: 1.4rem;
  cursor: pointer;
}

body.sheet-lock { overflow: hidden; }

/* footer */
.site-foot {
  background: var(--color-deep);
  color: var(--color-deep-ink);
  margin-top: 96px;
  padding-block: 64px 28px;
}
.foot-grid {
  display: grid;
  gap: 38px;
  grid-template-columns: 1fr;
}
.foot-brand .site-name { color: #fff; }
.foot-brand p { color: rgba(231,239,233,.74); font-size: .95rem; }
.foot-col h3 {
  color: #fff;
  font-family: var(--ff-body);
  font-size: .82rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  margin-bottom: 1rem;
}
.foot-col ul { list-style: none; padding: 0; margin: 0; }
.foot-col li { margin-bottom: .6em; }
.foot-col a { color: var(--color-deep-ink); font-size: .96rem; }
.foot-col a:hover { color: var(--color-accent); text-decoration: none; }
.foot-contact a { color: #fff; }

.foot-base {
  margin-top: 44px;
  padding-top: 22px;
  border-top: 1px solid rgba(255,255,255,.12);
  display: flex;
  flex-wrap: wrap;
  gap: 12px 26px;
  justify-content: space-between;
  font-size: .86rem;
  color: rgba(231,239,233,.62);
}
.foot-base a { color: rgba(231,239,233,.78); }

@media (min-width: 880px) {
  .main-nav { display: block; }
  .header-cta { display: inline-flex; }
  .nav-toggle { display: none; }
  .foot-grid { grid-template-columns: 1.6fr 1fr 1fr 1.2fr; gap: 48px; }
}