*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: 'Nunito', sans-serif;
  background: var(--cream);
  color: var(--text);
  line-height: 1.6;
}

img { max-width: 100%; display: block; }
a { color: inherit; }

.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
}

/* Buttons */
.btn {
  display: inline-block;
  font-family: 'Nunito', sans-serif;
  font-weight: 900;
  font-size: 14px;
  border-radius: 10px;
  padding: 11px 24px;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: transform .15s, box-shadow .15s;
}
.btn:hover { transform: translateY(-1px); }

.btn-primary {
  background: white;
  color: var(--brand-dark);
  box-shadow: 0 2px 10px rgba(0,0,0,0.12);
}
.btn-primary:hover { box-shadow: 0 4px 16px rgba(0,0,0,0.18); }

.btn-secondary {
  background: transparent;
  color: white;
  border: 2px solid rgba(255,255,255,0.5);
  padding: 9px 22px;
}
.btn-secondary:hover { background: rgba(255,255,255,0.1); }

/* Section headers */
.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 20px;
}
.section-title {
  font-family: 'Quicksand', sans-serif;
  font-size: 22px;
  font-weight: 700;
}
.see-all {
  font-size: 13px;
  font-weight: 800;
  color: var(--brand);
  text-decoration: none;
}
.see-all:hover { text-decoration: underline; }

/* Domain chips bar */
.domain-chips-bar {
  background: white;
  border-bottom: 1px solid var(--border);
  padding: 12px 0;
}
.domain-chips-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 40px;
  display: flex;
  gap: 8px;
  overflow-x: auto;
}
.domain-chip {
  display: inline-block;
  font-size: 13px;
  font-weight: 800;
  border-radius: 20px;
  padding: 5px 16px;
  text-decoration: none;
  white-space: nowrap;
  background: var(--border);
  color: var(--muted);
  transition: background .15s, color .15s;
}
.domain-chip:hover,
.domain-chip.active { background: var(--text); color: white; }
.domain-chip.chem { background: var(--chem-bg); color: var(--chem-text); }
.domain-chip.chem:hover { background: var(--chem-from); color: white; }
.domain-chip.phys { background: var(--phys-bg); color: var(--phys-text); }
.domain-chip.phys:hover { background: var(--phys-from); color: white; }

/* Articles section */
.articles-wrapper { padding: 48px 0 32px; }
.category-block { margin-bottom: 48px; }

/* Category page header */
.cat-header { padding: 48px 0 40px; }
.cat-header.young { background: linear-gradient(135deg, var(--young-bg), #C8E6C9); color: var(--young-text); }
.cat-header.all   { background: linear-gradient(135deg, var(--all-bg),   #FFE0B2); color: var(--all-text);   }
.cat-header.adv   { background: linear-gradient(135deg, var(--adv-bg),   #FFCDD2); color: var(--adv-text);   }
.cat-eyebrow {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 2px;
  text-transform: uppercase;
  opacity: .6;
  margin-bottom: 10px;
}
.cat-title {
  font-family: 'Quicksand', sans-serif;
  font-size: 38px;
  font-weight: 700;
  margin-bottom: 8px;
}
.cat-desc { font-size: 16px; max-width: 600px; opacity: .75; }