/* Edge-to-edge sticky top bar */
html #site-header {
  visibility: visible;
}

#site-header {
  height: var(--site-header-height);
  line-height: var(--site-header-height);
  max-width: 100%;
  margin: 0;
  background-color: var(--v-card-sectioning-background-color);
  border-bottom: var(--v-border-width) solid var(--v-muted-border-color);
  position: sticky;
  top: 0;
  z-index: 7;
  padding-top: 0 !important;
  padding-bottom: 0 !important;
  margin-top: 0 !important;
  margin-bottom: 0 !important;

  > nav {
    max-width: 1450px;
    margin-inline: auto;
    padding-inline: var(--v-spacing);
  }

  > nav :is(ul, ol, li):not(#search-dialog, #search-dialog *) {
    padding-block: 0 !important;
    margin-block: 0 !important;
  }
}

/* ---- Desktop: top bar ---- */
@media (min-width: 769px) {
  #site-header {
    /* Valence has no input alias (inputs are inimitable); approximate
       one with form-element tokens so the control reads as a search bar. */
    #site-search {
      margin-right: 24px;
      .tag-input {
        display: inline-block;
        min-width: 220px;
        padding-inline: var(--v-form-element-spacing-horizontal);
        line-height: calc(var(--site-header-height) / 2);
        background-color: var(--v-form-element-background-color);
        border: var(--v-border-width) solid var(--v-form-element-border-color);
        border-radius: var(--v-border-radius);
        cursor: pointer;
        color: var(--v-form-element-placeholder-color);
        position: relative;
        .shortcut {
          position: absolute;
          right: 8px;
          top: 50%;
          transform: translateY(-50%);
          color: var(--v-form-element-placeholder-color);
          font-size: 0.875rem;
          line-height: 0.875rem;
          font-weight: 500;
          padding: 4px;
          border-radius: var(--v-border-radius);
          background-color: var(--v-card-background-color);
          border: var(--v-border-width) solid var(--v-form-element-border-color);
        }
      }
    }

    #logos {
      display: flex;
      align-items: center;
      gap: var(--v-nav-element-spacing-horizontal);
      line-height: normal;
      spa-a {
        display: inline-block;
      }
      /* height-sized: a wordmark or a square icon both fit */
      img[src*="nucleus"] {
        height: calc(var(--site-header-height) / 1.4);
        width: auto;
        display: block;
      }
      img[src*="excom"] {
        height: calc(var(--site-header-height) / 3.4);
        width: auto;
        display: block;
        margin-top: 5px;
      }
      *:has(> img[src*="excom"]) {
        border-left: 4px solid var(--v-muted-border-color);
        border-radius: 0px;
        margin-left: 12px;
        padding: 0px 20px;
        color: var(--v-h5-color);
      }
    }

    /* Icon-only social links; `--ico` per `data-social` comes from shell.css */
    li:has([data-social]) {
      padding-inline: calc(var(--v-nav-element-spacing-horizontal) * 0.75);
    }
    [data-social] {
      display: flex;
      align-items: center;
      /* A flex box drops the bar's `line-height` centring, and Valence's
         nav-link rule adds a negative block margin; span the bar instead. */
      height: var(--site-header-height);
      margin-block: 0;
      color: var(--v-muted-color);
      text-decoration: none;
      cursor: pointer;
      transition: color var(--v-transition);
      &::before {
        content: "";
        width: 1.1rem;
        height: 1.1rem;
        background-color: currentColor;
        mask: var(--ico) center / contain no-repeat;
        -webkit-mask: var(--ico) center / contain no-repeat;
      }
      &:hover {
        color: var(--v-primary);
      }
      .tab-label {
        display: none;
      }
    }

    /* the tab labels are the link text; `[data-tab="home"]` shows the logo */
    [data-tab="home"] .tab-label,
    .mobile-only {
      display: none;
    }
  }
}

/* ---- Mobile: native-style bottom tab bar ---- */
@media (max-width: 768px) {
  #site-header {
    position: fixed;
    inset: auto 0 0 0;
    height: auto;
    line-height: normal;
    padding-bottom: env(safe-area-inset-bottom) !important;
    border-bottom: 0;
    border-top: var(--v-border-width) solid var(--v-muted-border-color);
    background-color: color-mix(
      in srgb,
      var(--v-card-sectioning-background-color) 88%,
      transparent
    );
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);

    .desktop-only {
      display: none;
    }
    .mobile-only,
    [data-tab="home"] .tab-label {
      display: block;
    }

    > nav {
      padding-inline: 0;
      justify-content: space-around;
      /* one row of tabs: the two lists dissolve into the nav */
      > ul {
        display: contents;
      }
      li {
        flex: 1 1 0;
        padding: 0;
      }
      li:has([data-tab="menu"]) {
        order: 1;
      }
      li:has([data-tab="search"]) {
        order: 2;
      }
      li:has([data-tab="home"]) {
        order: 3;
      }
      li:has([data-tab="github"]) {
        order: 4;
      }
    }

    /* a tab: icon above a small label, full-height tap target */
    [data-tab] {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 3px;
      width: 100%;
      min-height: var(--site-header-height);
      margin: 0;
      padding: 0.35rem 0;
      border: 0;
      border-radius: 0;
      background: none;
      box-shadow: none;
      color: var(--v-muted-color);
      font-size: 0.65rem;
      font-weight: 500;
      line-height: 1;
      letter-spacing: 0.01em;
      text-decoration: none;
      cursor: pointer;
      transition:
        color var(--v-transition),
        transform var(--v-transition-duration-fast) var(--v-transition-ease-out);
      &::before {
        content: "";
        width: 1.5rem;
        height: 1.5rem;
        background-color: currentColor;
        mask: var(--ico) center / contain no-repeat;
        -webkit-mask: var(--ico) center / contain no-repeat;
      }
      &:active {
        transform: scale(0.9);
      }
      &[is-active] {
        color: var(--v-primary);
      }
      img {
        display: none;
      }
    }
    [data-tab="home"] {
      --ico: var(--ico-home);
    }
    [data-tab="search"] {
      --ico: var(--ico-search);
      min-width: 0;
      line-height: 1;
    }
    [data-tab="menu"] {
      --ico: var(--ico-menu);
    }
    [data-tab="github"] {
      --ico: var(--ico-github);
    }
  }
}