/* Robot Collective — MD3 Top App Bar / Navigation
   Requires md3-tokens.css to be loaded first.
   Extracted from per-page inline styles to eliminate duplication.
*/

/* ── MD3 Top App Bar ─────────────────────────────────────────── */
header {
  position: fixed;
  top: 0;
  width: 100%;
  height: 64px; /* MD3 Top App Bar: 64dp */
  /* Surface + level-2 tonal elevation overlay */
  background-color: var(--md-sys-color-surface);
  background-image: linear-gradient(
    var(--md-sys-elevation-level2),
    var(--md-sys-elevation-level2)
  );
  backdrop-filter: blur(10px); /* Brand aesthetic — preserved */
  -webkit-backdrop-filter: blur(10px);
  z-index: 1000;
  padding: 0 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.35);
  transition: background-color var(--md-sys-motion-duration-medium2) var(--md-sys-motion-easing-standard);
}

nav {
  max-width: 1200px;
  height: 64px;
  margin: 0 auto;
  padding: 0 8px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
}

/* ── Logo / Title ────────────────────────────────────────────── */
.logo {
  font-family: var(--md-sys-typescale-font);
  font-size: var(--md-sys-typescale-title-large-size);
  font-weight: 500;
  line-height: var(--md-sys-typescale-title-large-line);
  white-space: nowrap;
  background: linear-gradient(
    45deg,
    var(--md-sys-color-primary),
    var(--md-sys-color-secondary)
  );
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  position: absolute;
  left: 50%;
  transform: translateX(-50%);
  text-decoration: none;
}

/* ── Dropdown wrapper ────────────────────────────────────────── */
.dropdown {
  position: relative;
  display: inline-block;
}

/* ── MD3 Icon Button ─────────────────────────────────────────── */
.dropdown-btn {
  background: transparent;
  border: none;
  color: var(--md-sys-color-on-surface-variant);
  width: 48px;
  height: 48px;
  border-radius: var(--md-sys-shape-full);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 24px;
  position: relative;
  overflow: hidden;
  transition: background-color var(--md-sys-motion-duration-short2) var(--md-sys-motion-easing-standard);
}

/* MD3 state layer on icon button */
.dropdown-btn::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: var(--md-sys-color-on-surface-variant);
  opacity: 0;
  transition: opacity var(--md-sys-motion-duration-short2) var(--md-sys-motion-easing-standard);
  pointer-events: none;
}

.dropdown-btn:hover::after  { opacity: 0.08; }
.dropdown-btn:active::after { opacity: 0.12; }

.dropdown-btn .material-symbols-outlined {
  font-size: 24px;
  color: var(--md-sys-color-on-surface-variant);
  font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 24;
}

/* ── MD3 Menu panel ──────────────────────────────────────────── */
.dropdown-content {
  display: none;
  position: absolute;
  /* Surface-variant + level-3 tonal overlay */
  background-color: var(--md-sys-color-surface-variant);
  background-image: linear-gradient(
    var(--md-sys-elevation-level3),
    var(--md-sys-elevation-level3)
  );
  min-width: 200px;
  border-radius: var(--md-sys-shape-extra-large); /* 28dp — MD3 menu shape */
  overflow: hidden;
  border: 1px solid var(--md-sys-color-outline);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.45);
  z-index: 1001;
}

.left-dropdown .dropdown-content {
  left: 0;
  top: 52px;
}

.right-dropdown .dropdown-content {
  right: 0;
  top: 52px;
}

/* MD3 List Item inside menu */
.dropdown-content a {
  color: var(--md-sys-color-on-surface-variant);
  padding: 14px 16px;
  font-family: var(--md-sys-typescale-font);
  font-size: var(--md-sys-typescale-label-large-size);
  font-weight: var(--md-sys-typescale-label-large-weight);
  letter-spacing: var(--md-sys-typescale-label-large-tracking);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 12px;
  white-space: nowrap;
  transition: background-color var(--md-sys-motion-duration-short2) var(--md-sys-motion-easing-standard);
}

.dropdown-content a:hover {
  background: rgba(158, 202, 255, 0.08); /* 8% primary state layer */
  color: var(--md-sys-color-on-surface);
}

.dropdown-content a .material-symbols-outlined {
  font-size: 20px;
  color: var(--md-sys-color-on-surface-variant);
  font-variation-settings: 'FILL' 0, 'wght' 400, 'GRAD' 0, 'opsz' 20;
}

.dropdown-content.show {
  display: block;
}

/* ── Nav container ───────────────────────────────────────────── */
.nav-container {
  display: flex;
  align-items: center;
}

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 768px) {
  .logo {
    font-size: 18px;
  }

  .dropdown-btn {
    width: 40px;
    height: 40px;
  }

  .dropdown-content {
    min-width: 160px;
  }
}