/* ==========================================================================
   Layout: shell, header, navigation, footer
   ========================================================================== */

.shell {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
}

/* ---------- Header ---------- */
.header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: color-mix(in srgb, var(--bg) 80%, transparent);
  -webkit-backdrop-filter: blur(16px) saturate(1.2);
  backdrop-filter: blur(16px) saturate(1.2);
  border-bottom: 1px solid transparent;
  transition: border-color 0.25s, box-shadow 0.25s;
}
.header.is-scrolled {
  border-bottom-color: var(--line);
  box-shadow: 0 6px 24px -18px rgba(34, 48, 43, 0.4);
}

.header__inner {
  display: flex;
  align-items: center;
  gap: var(--s-4);
  max-width: var(--maxw);
  height: var(--header-h);
  margin: 0 auto;
  padding: 0 var(--s-5);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  margin-right: auto;
}
.brand__mark { flex: none; }
.brand__name {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 600;
  letter-spacing: -0.02em;
}
.brand__name em { font-style: italic; color: var(--primary); }

.header__actions {
  display: flex;
  align-items: center;
  gap: var(--s-2);
}

/* ---------- Navigation (desktop) ---------- */
.nav--top {
  display: flex;
  gap: 2px;
  margin-right: var(--s-3);
}

.nav__link {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-height: 40px;
  padding: 0 16px;
  border-radius: var(--r-pill);
  color: var(--ink-2);
  font-weight: 500;
  font-size: var(--t-sm);
  text-decoration: none;
  transition: background 0.2s, color 0.2s;
}
.nav__link:hover { background: var(--surface-2); color: var(--ink); }
.nav__link[aria-current="page"] { background: var(--primary-soft); color: var(--on-primary-soft); font-weight: 600; }
.nav--top .nav__icon { display: none; }

.nav__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
  box-shadow: 0 0 0 3px var(--primary-soft);
  animation: breathe-dot 2.4s ease-in-out infinite;
}

@keyframes breathe-dot {
  0%, 100% { transform: scale(0.85); opacity: 0.8; }
  50% { transform: scale(1.15); opacity: 1; }
}

.identity-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 4px 12px 4px 4px;
  border: 1px solid var(--line-strong);
  border-radius: var(--r-pill);
  background: var(--surface);
  cursor: pointer;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.identity-btn:hover { border-color: var(--primary); box-shadow: var(--shadow-1); }
.identity-btn__name { font-size: var(--t-xs); font-weight: 600; max-width: 9rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* ---------- Main ---------- */
.main {
  flex: 1;
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: var(--s-6) var(--s-5) var(--s-8);
  outline: none;
}

.main--narrow { max-width: calc(var(--maxw-text) + 2 * var(--s-5)); }

/* ---------- Footer ---------- */
.footer {
  border-top: 1px solid var(--line);
  padding: var(--s-6) var(--s-5) var(--s-7);
  color: var(--ink-2);
  font-size: var(--t-sm);
}
.footer__inner {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-4) var(--s-6);
  justify-content: space-between;
  align-items: center;
  max-width: var(--maxw);
  margin: 0 auto;
}
.footer__links { display: flex; gap: var(--s-5); }
.footer a { text-decoration: none; font-weight: 500; }
.footer a:hover { color: var(--primary); text-decoration: underline; }

/* ---------- Bottom tab bar (mobile) ---------- */
.tabbar { display: none; }

@media (max-width: 820px) {
  .header__inner { padding: 0 var(--s-4); gap: var(--s-2); }
  .nav--top { display: none; }
  .identity-btn__name { display: none; }
  .identity-btn { padding: 4px; }
  .help-now__label { display: none; }

  .main { padding: var(--s-5) var(--s-4) calc(var(--tabbar-h) + var(--s-7)); }
  .footer { padding-bottom: calc(var(--tabbar-h) + var(--s-6)); }

  .tabbar {
    position: fixed;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 60;
    display: block;
    padding-bottom: env(safe-area-inset-bottom);
    background: color-mix(in srgb, var(--surface) 88%, transparent);
    -webkit-backdrop-filter: blur(18px);
    backdrop-filter: blur(18px);
    border-top: 1px solid var(--line);
  }
  .nav--tabs {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    height: var(--tabbar-h);
    max-width: 560px;
    margin: 0 auto;
  }
  .nav--tabs .nav__link {
    flex-direction: column;
    justify-content: center;
    gap: 3px;
    min-height: 0;
    padding: 6px 2px;
    border-radius: var(--r-md);
    font-size: 0.68rem;
    font-weight: 600;
    background: none;
  }
  .nav--tabs .nav__link[aria-current="page"] { color: var(--primary); background: none; }
  .nav--tabs .nav__link[aria-current="page"] .nav__icon { background: var(--primary-soft); }
  .nav--tabs .nav__icon {
    display: grid;
    place-items: center;
    width: 52px;
    height: 28px;
    border-radius: var(--r-pill);
    transition: background 0.25s var(--ease);
  }
  .nav--tabs .nav__dot { position: absolute; top: 8px; right: calc(50% - 26px); }
}

@media (min-width: 821px) {
  .nav--tabs { display: none; }
}