/* ═══════════════════════════════════════════════════════════
   TIANX STUDIO — Portfolio Page
   ═══════════════════════════════════════════════════════════ */

/* ─── PAGE HEADER ──────────────────────────────────────── */

.page-header {
  padding: 8rem 0 var(--space-lg);
  background: var(--surface-dark);
  color: var(--text-inverse);
}

.page-header__title {
  color: #fff;
  margin-bottom: var(--space-xs);
}

.page-header__desc {
  font-size: 1.05rem;
  color: rgba(255,255,255,0.5);
  max-width: 52ch;
  line-height: 1.7;
}

/* ─── FILTER BAR ───────────────────────────────────────── */

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--border);
  margin-bottom: var(--space-lg);
}

.filter-btn {
  padding: 8px 20px;
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  border-radius: var(--radius-pill);
  color: var(--text-muted);
  border: 1px solid var(--border);
  background: transparent;
  cursor: pointer;
  transition: all var(--duration-sm) var(--ease);
}

.filter-btn:hover {
  color: var(--text-primary);
  border-color: var(--border-strong);
}

.filter-btn.active {
  background: var(--primary);
  color: var(--surface);
  border-color: var(--primary);
}

/* ─── PROJECT GRID ─────────────────────────────────────── */

.portfolio-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
}

/* Full-width card for hero project */
.project-card--hero {
  grid-column: 1 / -1;
}

.project-card--hero .project-card__image {
  height: 360px;
}

/* Project detail expansion */
.project-card__detail {
  display: none;
  padding: var(--space-md);
  padding-top: 0;
  border-top: 1px solid var(--border);
  margin-top: var(--space-sm);
}

.project-card__detail.open {
  display: block;
}

.project-card__detail-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-md);
  margin-top: var(--space-sm);
}

.project-card__detail-section h4 {
  font-family: var(--font-body);
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
}

.project-card__detail-section p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.65;
}

/* Tech stack badges in detail */
.project-card__tech-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2xs);
  margin-top: var(--space-xs);
}

/* Live link in card */
.project-card__live-link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--signal);
  font-size: 0.82rem;
  font-weight: 500;
  transition: color var(--duration-sm);
}

.project-card__live-link:hover {
  color: var(--signal-dark);
}

.project-card__live-link svg {
  width: 14px;
  height: 14px;
}

/* ─── RESPONSIVE ───────────────────────────────────────── */

@media (max-width: 768px) {
  .portfolio-grid {
    grid-template-columns: 1fr;
  }
  .project-card--hero .project-card__image {
    height: 240px;
  }
  .project-card__detail-grid {
    grid-template-columns: 1fr;
  }
}