/* ==========================================================================
   components.css — Reusable UI components
   ==========================================================================
   Components defined here:
     - Buttons (.btn, .btn-primary, .btn-outline, .btn-sm)
     - Icon buttons (.btn-icon, .theme-toggle, .hamburger)
     - Nav links (.nav-link)
     - Search input (.search-input)
     - Tag pills (.tag)
     - Post cards (.post-card)
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. Buttons
   -------------------------------------------------------------------------- */

/* Base button — extend with modifier classes below */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-6);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  cursor: pointer;
  transition:
    background-color var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast);
  white-space: nowrap;
  user-select: none;
}

.btn:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

/* Primary — filled */
.btn-primary {
  background-color: var(--color-primary);
  color: var(--color-primary-fg);
  border-color: var(--color-primary);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.15);
}

.btn-primary:hover {
  background-color: var(--color-primary-hover);
  border-color: var(--color-primary-hover);
  color: var(--color-primary-fg);
  box-shadow: 0 4px 12px rgba(37, 99, 235, 0.25);
  transform: translateY(-1px);
}

.btn-primary:active {
  transform: translateY(0);
}

/* Outline — ghost style */
.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
  transition:
    background-color var(--transition-base),
    color var(--transition-base),
    box-shadow var(--transition-base);
}

.btn-outline:hover {
  background-color: var(--color-primary);
  color: var(--color-primary-fg);
  box-shadow: 0 2px 8px rgba(37, 99, 235, 0.15);
}

.btn-outline:active {
  transform: translateY(0);
}

/* Size modifier — small */
.btn-sm {
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-sm);
  border-radius: var(--radius-sm);
}

/* --------------------------------------------------------------------------
   2. Icon buttons (.btn-icon)
   Used for theme toggle and hamburger.
   -------------------------------------------------------------------------- */
.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  padding: 0;
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  color: var(--color-text);
  transition: background-color var(--transition-fast);
}

.btn-icon:hover {
  background-color: var(--color-bg-alt);
}

.btn-icon:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

/* Theme toggle icon visibility — controlled by [data-theme] on <html> */
.theme-toggle .icon-moon { display: none; }
.theme-toggle .icon-sun  { display: inline; }

[data-theme="dark"] .theme-toggle .icon-sun  { display: none; }
[data-theme="dark"] .theme-toggle .icon-moon { display: inline; }

/* Hamburger lines */
.hamburger-line {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-fast);
}

/* --------------------------------------------------------------------------
   3. Nav links
   -------------------------------------------------------------------------- */
.nav-link {
  display: inline-block;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-sm);
  color: var(--color-text-muted);
  font-size: var(--text-sm);
  font-weight: 500;
  text-decoration: none;
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
  background-color: var(--color-tag-bg);
}

.nav-link:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

@media (max-width: 767px) {
  .nav-link {
    display: block;
    padding: var(--space-3) var(--space-4);
    font-size: var(--text-base);
    border-radius: var(--radius-md);
  }
}

/* --------------------------------------------------------------------------
   4. Search input — theme-aware styling with smooth transitions
   -------------------------------------------------------------------------- */
.search-input {
  width: 100%;
  max-width: 420px;
  padding: var(--space-2) var(--space-4);
  background-color: var(--color-surface);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-full);
  color: var(--color-text);
  font-size: var(--text-base);
  /* Smooth transitions on theme change and interactions */
  transition:
    background-color var(--transition-base),
    color var(--transition-base),
    border-color var(--transition-fast),
    box-shadow var(--transition-fast);
}

.search-input::placeholder {
  color: var(--color-text-subtle);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.2);
}

/* --------------------------------------------------------------------------
   5. Tag pills — filter buttons with smooth interactions
   -------------------------------------------------------------------------- */
.tag {
  display: inline-flex;
  align-items: center;
  padding: var(--space-1) var(--space-3);
  background-color: var(--color-tag-bg);
  color: var(--color-tag-text);
  border-radius: var(--radius-full);
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  text-decoration: none;
  cursor: pointer;
  border: 1.5px solid transparent;
  transition:
    background-color var(--transition-fast),
    border-color var(--transition-fast),
    color var(--transition-fast);
  user-select: none;
}

.tag:hover {
  /* Darker/lighter background on hover depending on theme */
  filter: brightness(0.92);
  border-color: var(--color-primary);
}

.tag.active {
  background-color: var(--color-primary);
  color: var(--color-primary-fg);
  border-color: var(--color-primary);
}

.tag:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 1px;
}

/* --------------------------------------------------------------------------
   6. Post cards — link elements, fully clickable and keyboard accessible
   -------------------------------------------------------------------------- */
.post-card {
  display: flex;
  flex-direction: column;
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  text-decoration: none;
  color: inherit;
  cursor: pointer;
  transition:
    box-shadow var(--transition-base),
    transform var(--transition-base),
    border-color var(--transition-base),
    background-color var(--transition-base);
}

.post-card:hover {
  box-shadow: 0 12px 32px var(--color-shadow);
  transform: translateY(-6px);
  border-color: var(--color-primary);
  background-color: var(--color-bg);
}

.post-card:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 2px;
}

.post-card-title {
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: var(--space-2);
  line-height: var(--lh-tight);
}

.post-card-excerpt {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
  line-height: var(--lh-prose);
  flex: 1;
  margin-bottom: var(--space-4);
}

.post-card-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.post-card-date {
  font-size: var(--text-xs);
  color: var(--color-text-subtle);
}

.post-card-tags {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

/* --------------------------------------------------------------------------
   7. Tag filter bar (posts page) — spacing and layout
   -------------------------------------------------------------------------- */
.tag-filters {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
  margin-top: var(--space-8);  /* Increased from space-4 for better visual hierarchy */
}
