/* ═══════════════════════════════════════════
   Navigation 2.0 — Glass morph + Scroll hide + Orb cursor + Bottom tab
   Design: tech-humanist, frosted glass, fluid micro-interactions
   ═══════════════════════════════════════════ */

/* ── CSS Custom Properties ── */
:root {
  --nav-height: 4rem;
  --nav-glass-bg: rgba(255,255,255,0.72);
  --nav-glass-border: rgba(0,0,0,0.06);
  --nav-glass-shadow: 0 1px 3px rgba(0,0,0,0.04);
  --nav-text: #1e293b;
  --nav-text-dim: #64748b;
  --nav-accent: #6366f1;
  --nav-orb-size: 260px;
  --nav-transition: 0.35s cubic-bezier(0.16, 1, 0.3, 1);
  --nav-ease-out: 0.25s cubic-bezier(0, 0, 0.2, 1);
}
[data-theme="dark"] {
  --nav-glass-bg: rgba(15,23,42,0.78);
  --nav-glass-border: rgba(255,255,255,0.05);
  --nav-glass-shadow: 0 1px 3px rgba(0,0,0,0.2);
  --nav-text: #e2e8f0;
  --nav-text-dim: #94a3b8;
  --nav-accent: #818cf8;
}

/* ── Header container ── */
.nav-main {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 50;
  height: var(--nav-height);
  transition: transform var(--nav-transition), background var(--nav-transition), box-shadow var(--nav-transition);
  will-change: transform;
}
.nav-main.hidden-up { transform: translateY(-100%); }

/* ── Glass surface ── */
.nav-glass {
  position: absolute;
  inset: 0;
  background: var(--nav-glass-bg);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
  border-bottom: 1px solid var(--nav-glass-border);
  box-shadow: var(--nav-glass-shadow);
  transition: background var(--nav-transition), border-color var(--nav-transition), box-shadow var(--nav-transition);
}

/* ── Magic orb (cursor follower, desktop only) ── */
.nav-orb {
  position: fixed;
  pointer-events: none;
  z-index: 49;
  width: var(--nav-orb-size);
  height: var(--nav-orb-size);
  border-radius: 50%;
  background: radial-gradient(circle at center,
    rgba(99,102,241,0.12) 0%,
    rgba(139,92,246,0.06) 35%,
    rgba(167,139,250,0.02) 60%,
    transparent 70%
  );
  transform: translate(-50%, -50%);
  opacity: 0;
  transition: opacity 0.3s ease;
  filter: blur(2px);
}
.nav-orb.active { opacity: 1; }
@media (max-width: 767px) {
  .nav-orb { display: none; }
}

/* ── Inner wrapper ── */
.nav-inner {
  position: relative;
  z-index: 1;
  max-width: 64rem;
  margin: 0 auto;
  padding: 0 1.25rem;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

/* ── Logo ── */
.nav-logo {
  display: flex;
  align-items: baseline;
  gap: 2px;
  text-decoration: none;
  font-family: var(--font-mono, "SF Mono","Fira Code","JetBrains Mono",monospace);
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: -0.02em;
  color: var(--nav-text);
  transition: opacity 0.2s;
  flex-shrink: 0;
}
.nav-logo:hover { opacity: 0.75; }
.nav-logo-text { color: var(--nav-text); }
.nav-logo-dot { color: var(--nav-accent); margin: 0 1px; }
.nav-logo-sub { color: var(--nav-text-dim); font-weight: 500; font-size: 0.88em; }

/* ── Desktop nav links ── */
.nav-links {
  display: none;
  align-items: center;
  gap: 2rem;
  font-size: 0.9rem;
  font-weight: 480;
}
@media (min-width: 768px) {
  .nav-links { display: flex; }
}
.nav-links a {
  color: var(--nav-text-dim);
  text-decoration: none;
  position: relative;
  padding: 0.35rem 0;
  transition: color 0.15s;
  white-space: nowrap;
}
.nav-links a:hover { color: var(--nav-text); }
.nav-links a.active { color: var(--nav-accent); font-weight: 600; }
/* Underline animation */
.nav-links a::after {
  content: "";
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 2px;
  background: var(--nav-accent);
  border-radius: 2px;
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--nav-transition);
}
.nav-links a:hover::after,
.nav-links a.active::after { transform: scaleX(1); }

/* ── Right actions group ── */
.nav-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* ── Icon button base ── */
.nav-icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px; height: 38px;
  border-radius: 50%;
  border: none;
  background: transparent;
  color: var(--nav-text-dim);
  cursor: pointer;
  transition: all 0.2s ease;
  position: relative;
  flex-shrink: 0;
}
.nav-icon-btn:hover {
  color: var(--nav-accent);
  background: rgba(99,102,241,0.08);
}
.nav-icon-btn:active { transform: scale(0.92); }

/* Theme toggle icon rotation */
.nav-theme-btn .icon-sun,
.nav-theme-btn .icon-moon {
  position: absolute;
  transition: transform 0.4s cubic-bezier(0.34,1.56,0.64,1), opacity 0.3s ease;
}
.nav-theme-btn .icon-moon { opacity: 1; transform: rotate(0deg) scale(1); }
.nav-theme-btn .icon-sun  { opacity: 0; transform: rotate(90deg) scale(0); }
[data-theme="dark"] .nav-theme-btn .icon-moon { opacity: 0; transform: rotate(-90deg) scale(0); }
[data-theme="dark"] .nav-theme-btn .icon-sun  { opacity: 1; transform: rotate(0deg) scale(1); }

/* ── Hamburger ── */
.nav-hamburger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 36px; height: 36px;
  background: none; border: none;
  cursor: pointer;
  padding: 6px;
  color: var(--nav-text);
  flex-shrink: 0;
}
@media (min-width: 768px) { .nav-hamburger { display: none; } }
.nav-hamburger span {
  display: block;
  width: 100%; height: 2px;
  background: currentColor;
  border-radius: 2px;
  transition: all 0.3s cubic-bezier(0.16,1,0.3,1);
  transform-origin: center;
}
.nav-hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-hamburger.open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
.nav-hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Mobile drawer ── */
.nav-drawer {
  position: fixed;
  top: 0; right: 0;
  width: 280px; height: 100vh;
  z-index: 55;
  background: var(--color-surface, #fff);
  padding: 5rem 1.5rem 2rem;
  transform: translateX(100%);
  transition: transform 0.35s cubic-bezier(0.16,1,0.3,1);
  overflow-y: auto;
  box-shadow: -8px 0 30px rgba(0,0,0,0.08);
}
.nav-drawer.open { transform: translateX(0); }
.nav-drawer a {
  display: block;
  padding: 14px 0;
  font-size: 1.1rem;
  font-weight: 500;
  color: var(--color-text, #1e293b);
  text-decoration: none;
  border-bottom: 1px solid var(--color-border-light, #f1f5f9);
  transition: color 0.15s;
}
.nav-drawer a:hover,
.nav-drawer a.active { color: var(--nav-accent); }
.nav-drawer-divider {
  height: 1px;
  background: var(--color-border-light, #f1f5f9);
  margin: 12px 0;
}

.nav-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.3);
  z-index: 50;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
}
.nav-overlay.open { opacity: 1; pointer-events: auto; }

/* ── Hero glass variant (transparent until scroll) ── */
.nav-hero .nav-glass { background: transparent; backdrop-filter: none; -webkit-backdrop-filter: none; border-bottom-color: transparent; box-shadow: none; }
.nav-hero .nav-logo { color: #fff; }
.nav-hero .nav-logo-text { color: #fff; }
.nav-hero .nav-logo-sub { color: rgba(255,255,255,0.7); }
.nav-hero .nav-logo-dot { color: rgba(255,255,255,0.9); }
.nav-hero .nav-links a { color: rgba(255,255,255,0.72); }
.nav-hero .nav-links a:hover { color: #fff; }
.nav-hero .nav-links a.active { color: #fff; font-weight: 600; }
.nav-hero .nav-links a::after { background: rgba(255,255,255,0.85); }
.nav-hero .nav-icon-btn { color: rgba(255,255,255,0.7); }
.nav-hero .nav-icon-btn:hover { color: #fff; background: rgba(255,255,255,0.12); }
.nav-hero .nav-hamburger { color: #fff; }

/* Hero -> glass transition on scroll */
.nav-hero.scrolled .nav-glass { background: var(--nav-glass-bg); backdrop-filter: blur(16px) saturate(1.4); -webkit-backdrop-filter: blur(16px) saturate(1.4); border-bottom-color: var(--nav-glass-border); box-shadow: var(--nav-glass-shadow); }
.nav-hero.scrolled .nav-logo { color: var(--nav-text); }
.nav-hero.scrolled .nav-logo-text { color: var(--nav-text); }
.nav-hero.scrolled .nav-logo-sub { color: var(--nav-text-dim); }
.nav-hero.scrolled .nav-logo-dot { color: var(--nav-accent); }
.nav-hero.scrolled .nav-links a { color: var(--nav-text-dim); }
.nav-hero.scrolled .nav-links a:hover { color: var(--nav-text); }
.nav-hero.scrolled .nav-links a.active { color: var(--nav-accent); }
.nav-hero.scrolled .nav-links a::after { background: var(--nav-accent); }
.nav-hero.scrolled .nav-icon-btn { color: var(--nav-text-dim); }
.nav-hero.scrolled .nav-icon-btn:hover { color: var(--nav-accent); background: rgba(99,102,241,0.08); }
.nav-hero.scrolled .nav-hamburger { color: var(--nav-text); }
[data-theme="dark"] .nav-hero.scrolled .nav-glass { background: rgba(15,23,42,0.78); }

/* ── Mobile bottom tab bar (< 768px) ── */
.nav-bottom { display: none; }
@media (max-width: 767px) {
  .nav-bottom {
    display: flex;
    position: fixed;
    bottom: 0; left: 0; right: 0;
    z-index: 45;
    background: var(--nav-glass-bg);
    backdrop-filter: blur(16px) saturate(1.4);
    -webkit-backdrop-filter: blur(16px) saturate(1.4);
    border-top: 1px solid var(--nav-glass-border);
    padding: 6px 0 max(6px, env(safe-area-inset-bottom));
    justify-content: space-around;
    transition: transform var(--nav-transition), background var(--nav-transition);
    will-change: transform;
  }
  .nav-bottom.hidden-down { transform: translateY(100%); }

  .nav-bottom a,
  .nav-bottom button {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
    color: var(--nav-text-dim);
    text-decoration: none;
    font-size: 10px;
    font-weight: 500;
    padding: 2px 12px;
    border-radius: 8px;
    border: none;
    background: none;
    cursor: pointer;
    transition: color 0.15s, background 0.15s;
    -webkit-tap-highlight-color: transparent;
    white-space: nowrap;
  }
  .nav-bottom a.active,
  .nav-bottom a:active { color: var(--nav-accent); }
  .nav-bottom a svg,
  .nav-bottom button svg { width: 22px; height: 22px; }

  /* Hide top-bar icons on mobile — bottom tab covers them */
  .nav-icon-btn.nav-theme-btn,
  .nav-icon-btn.nav-search-btn,
  .nav-icon-btn.nav-github-btn {
    display: none;
  }

  body { padding-bottom: 68px; }
}

/* ── Hide FAB on mobile (bottom tab replaces it) ── */
@media (max-width: 767px) {
  .fab-container { display: none !important; }
}

/* ── Search modal ── */
.search-modal {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  justify-content: center;
  padding-top: 18vh;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.25s ease;
}
.search-modal.open { opacity: 1; pointer-events: auto; }

.search-backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.4);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
}

.search-panel {
  position: relative;
  width: 90vw;
  max-width: 520px;
  max-height: 60vh;
  background: var(--color-surface, #fff);
  border-radius: 16px;
  border: 1px solid var(--color-border, #e2e8f0);
  box-shadow: 0 20px 60px rgba(0,0,0,0.15), 0 0 0 1px rgba(0,0,0,0.05);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transform: translateY(12px) scale(0.97);
  transition: transform 0.3s cubic-bezier(0.16,1,0.3,1);
}
.search-modal.open .search-panel { transform: translateY(0) scale(1); }

.search-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--color-border-light, #f1f5f9);
  color: var(--nav-text-dim);
}
.search-bar input {
  flex: 1;
  border: none;
  outline: none;
  font-size: 1rem;
  font-family: inherit;
  color: var(--color-text, #1e293b);
  background: transparent;
}
.search-bar input::placeholder { color: var(--nav-text-dim); }
.search-kbd {
  font-size: 0.7rem;
  padding: 2px 8px;
  border-radius: 5px;
  background: var(--color-surface-alt, #f1f5f9);
  color: var(--nav-text-dim);
  font-family: var(--font-mono, monospace);
  border: 1px solid var(--color-border, #e2e8f0);
}

.search-results {
  overflow-y: auto;
  padding: 8px;
  flex: 1;
}
.search-results a {
  display: block;
  padding: 12px 16px;
  border-radius: 10px;
  text-decoration: none;
  color: var(--color-text, #1e293b);
  transition: background 0.15s;
}
.search-results a:hover,
.search-results a.focus { background: var(--color-surface-alt, #f1f5f9); }
.search-results .result-title { font-size: 0.95rem; font-weight: 500; }
.search-results .result-date { font-size: 0.75rem; color: var(--nav-text-dim); margin-top: 4px; }
.search-empty {
  text-align: center;
  padding: 32px 16px;
  color: var(--nav-text-dim);
  font-size: 0.9rem;
}

/* Dark mode overrides */
[data-theme="dark"] .search-backdrop { background: rgba(0,0,0,0.6); }
[data-theme="dark"] .search-panel { background: #1e293b; border-color: #334155; }
[data-theme="dark"] .search-kbd { background: #334155; border-color: #475569; }
[data-theme="dark"] .search-bar { border-color: #334155; }
[data-theme="dark"] .search-bar input { color: #e2e8f0; }
[data-theme="dark"] .nav-drawer { background: #1e293b; }
[data-theme="dark"] .nav-drawer a { color: #e2e8f0; border-color: #334155; }
[data-theme="dark"] .nav-drawer-divider { background: #334155; }
[data-theme="dark"] .nav-bottom { background: rgba(15,23,42,0.85); }
[data-theme="dark"] .search-results a:hover,
[data-theme="dark"] .search-results a.focus { background: #334155; }