/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(12px);
  background: rgba(255, 255, 255, 0.82);
  border-bottom: 1px solid var(--line);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: 24px;
  height: 76px;
}
.brand { display: flex; align-items: center; gap: 14px; flex-shrink: 0; }
.brand-mark { width: 40px; height: 40px; color: var(--cyan-deep); animation: spin 22s linear infinite; }
.brand-title {
  font-family: var(--display);
  font-weight: 800;
  font-size: 20px;
  letter-spacing: 0.18em;
  color: var(--ink);
  line-height: 1.1;
}
.brand-title span { color: var(--cyan-deep); }
.brand-sub {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.28em;
  color: var(--ink-faint);
  margin-top: 2px;
}

/* Header search — pill in the middle, flex-grows */
.header-search {
  flex: 1;
  display: flex;
  align-items: center;
  background: var(--bg-soft);
  border: 1.5px solid var(--line);
  border-radius: 999px;
  padding: 6px 10px 6px 16px;
  max-width: 560px;
  margin: 0 auto;
  transition: border-color 0.18s, box-shadow 0.18s, background 0.18s;
}
.header-search:focus-within {
  background: #fff;
  border-color: var(--cyan);
  box-shadow: 0 8px 22px -10px rgba(14, 165, 233, 0.45), 0 0 0 4px rgba(14, 165, 233, 0.10);
}
.header-search .ico {
  width: 18px; height: 18px;
  color: var(--cyan-deep);
  flex-shrink: 0;
}
#searchInput {
  flex: 1;
  background: transparent;
  border: 0;
  padding: 8px 12px;
  font-size: 14.5px;
  color: var(--ink);
  outline: none;
  min-width: 0;
}
#searchInput::placeholder { color: var(--ink-faint); }
.header-search kbd {
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  background: rgba(11, 34, 64, 0.06);
  border: 1px solid var(--line);
  color: var(--ink-dim);
  padding: 3px 8px;
  border-radius: 999px;
  white-space: nowrap;
}

.header-actions { flex-shrink: 0; display: flex; gap: 8px; }

/* HERO — 2 columns: text + HCMUT photo */
.hero {
  padding: 64px 0 60px;
  position: relative;
  border-bottom: 1px solid var(--line);
}
.hero::before, .hero::after {
  content: ''; position: absolute; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--line-strong), transparent);
}
.hero::before { top: 0; }
.hero::after { bottom: -1px; }
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.15fr) minmax(280px, 1fr);
  gap: 56px;
  align-items: center;
}
.hero-tag {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.4em;
  color: var(--cyan-deep);
  margin-bottom: 16px;
  opacity: 0.95;
}
.hero-title {
  font-family: var(--display);
  font-weight: 800;
  font-size: clamp(28px, 4vw, 50px);
  line-height: 1.12;
  margin: 0 0 18px;
  letter-spacing: 0.01em;
  color: var(--ink);
}
.hero-title .accent {
  background: linear-gradient(120deg, var(--cyan-deep) 0%, var(--cyan) 50%, var(--amber) 130%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.hero-title .accent-num {
  color: var(--amber);
  font-feature-settings: 'tnum';
}
.hero-sub {
  font-size: 16.5px;
  color: var(--ink-dim);
  max-width: 600px;
  margin: 0 0 32px;
}
.hero-stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 1px;
  max-width: 560px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}
.stat {
  padding: 16px 18px;
  background: var(--panel);
  position: relative;
}
.stat::before {
  content: ''; position: absolute; top: 9px; right: 9px;
  width: 6px; height: 6px; border: 1px solid var(--cyan); border-radius: 50%;
  opacity: 0.55;
}
.stat-num {
  font-family: var(--display);
  font-weight: 800;
  font-size: 28px;
  color: var(--cyan-deep);
  line-height: 1;
}
.stat-lbl {
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-faint);
  margin-top: 6px;
}

/* HCMUT Photo block — blueprint style frame */
.hero-media { position: relative; }
.photo-card {
  position: relative;
  margin: 0;
  padding: 14px 14px 18px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  isolation: isolate;
}
.photo-card::before {
  content: '';
  position: absolute;
  inset: -10px;
  border: 1px dashed var(--line-strong);
  border-radius: calc(var(--radius-lg) + 6px);
  pointer-events: none;
  z-index: -1;
  opacity: 0.55;
}
.photo-card .corner {
  position: absolute;
  width: 16px; height: 16px;
  border: 1.5px solid var(--cyan-deep);
}
.photo-card .corner.tl { top: -1px; left: -1px; border-right: none; border-bottom: none; }
.photo-card .corner.tr { top: -1px; right: -1px; border-left: none; border-bottom: none; }
.photo-card .corner.bl { bottom: -1px; left: -1px; border-right: none; border-top: none; }
.photo-card .corner.br { bottom: -1px; right: -1px; border-left: none; border-top: none; }
.photo-stamp {
  position: absolute;
  top: -12px; right: 22px;
  z-index: 2;
  padding: 4px 10px;
  background: var(--cyan-deep);
  color: #fff;
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  border-radius: 3px;
  box-shadow: 0 6px 14px -6px rgba(3, 105, 161, 0.6);
}
.photo-img-wrap {
  position: relative;
  aspect-ratio: 4 / 3;
  background: linear-gradient(135deg, #E6F2FB, #D7E8F5);
  border-radius: var(--radius);
  overflow: hidden;
}
.photo-img-wrap img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.photo-img-wrap::after {
  content: '';
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(11, 34, 64, 0.15) 100%);
  pointer-events: none;
}
.photo-caption {
  padding-top: 14px;
  display: flex;
  flex-direction: column;
  gap: 4px;
  position: relative;
}
.photo-caption::before {
  content: '';
  position: absolute;
  left: 0; top: 6px;
  width: 28px; height: 2px;
  background: var(--cyan);
}
.photo-caption strong {
  font-family: var(--display);
  font-weight: 700;
  font-size: 14px;
  color: var(--ink);
  letter-spacing: 0.04em;
}
.photo-caption .sub {
  font-family: var(--mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-faint);
}
.photo-dim {
  position: absolute;
  bottom: 26px; left: -8px;
  writing-mode: vertical-rl;
  transform: rotate(180deg);
  font-family: var(--mono);
  font-size: 9.5px;
  letter-spacing: 0.32em;
  color: var(--cyan-deep);
  opacity: 0.6;
  text-transform: uppercase;
}

/* Toolbar — chips only */
.toolbar {
  padding: 14px 0 16px;
  position: sticky;
  top: 76px;
  z-index: 20;
  background: rgba(247, 250, 252, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.toolbar-inner {
  display: flex;
  gap: 12px;
  align-items: center;
  flex-wrap: wrap;
  justify-content: center;
}
.chips { display: flex; gap: 8px; flex-wrap: wrap; justify-content: center; }
.chip {
  background: var(--panel);
  border: 1px solid var(--line);
  color: var(--ink-dim);
  padding: 7px 14px;
  border-radius: 999px;
  cursor: pointer;
  font-family: var(--mono);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  transition: all 0.15s;
  box-shadow: var(--shadow-sm);
}
.chip:hover { color: var(--cyan-deep); border-color: var(--cyan); }
.chip.is-active {
  background: var(--cyan-deep);
  border-color: var(--cyan-deep);
  color: #fff;
  box-shadow: 0 6px 14px -6px rgba(3, 105, 161, 0.55);
}
.chip .count { opacity: 0.7; margin-left: 4px; font-weight: 400; }

/* Main grid section */
.main { padding: 30px 0 90px; min-height: 50vh; }

.empty {
  margin: 50px auto;
  max-width: 480px;
  text-align: center;
}
.empty-frame {
  border: 1px dashed var(--line-strong);
  border-radius: var(--radius-lg);
  padding: 36px 24px;
  background: var(--panel);
  box-shadow: var(--shadow-sm);
}
.empty-title { font-family: var(--display); font-size: 18px; color: var(--ink); margin-bottom: 6px; }
.empty-sub { color: var(--ink-faint); font-size: 14px; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 26px 0;
  background: rgba(255, 255, 255, 0.7);
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
}
.foot-brand {
  font-family: var(--mono);
  font-size: 11.5px;
  letter-spacing: 0.24em;
  color: var(--cyan-deep);
}
.foot-meta {
  font-family: var(--mono);
  font-size: 11.5px;
  color: var(--ink-faint);
  letter-spacing: 0.12em;
}

/* FAB */
.fab {
  position: fixed;
  right: 28px; bottom: 28px;
  width: 60px; height: 60px;
  border-radius: 50%;
  border: 0;
  background: linear-gradient(135deg, var(--cyan) 0%, var(--cyan-deep) 100%);
  color: #fff;
  font-size: 28px;
  font-weight: 600;
  cursor: pointer;
  z-index: 40;
  display: grid;
  place-items: center;
  box-shadow: 0 14px 32px -10px rgba(14, 165, 233, 0.6), 0 0 0 6px rgba(14, 165, 233, 0.08);
  transition: all 0.22s;
}
.fab:hover { transform: translateY(-3px) scale(1.05); box-shadow: 0 18px 42px -10px rgba(14, 165, 233, 0.78); }
.fab-gear { line-height: 1; }

@media (max-width: 920px) {
  .hero-grid { grid-template-columns: 1fr; gap: 36px; }
  .hero-media { max-width: 460px; margin: 0 auto; width: 100%; }
  .hero { padding: 50px 0 44px; }
  .header-search kbd { display: none; }
}
@media (max-width: 720px) {
  .container { padding: 0 18px; }
  .header-inner {
    height: auto;
    padding: 12px 0;
    flex-wrap: wrap;
    gap: 12px;
  }
  .brand-sub { display: none; }
  .header-search {
    order: 3;
    flex: 1 0 100%;
    max-width: none;
    margin: 0;
  }
  .header-search .ico { width: 16px; height: 16px; }
  .header-actions .btn { padding: 8px 12px; font-size: 11px; }
  .header-actions .btn span:not(.btn-icon) { display: none; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .toolbar { top: auto; position: static; }
  .fab { right: 18px; bottom: 18px; width: 52px; height: 52px; font-size: 24px; }
}