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

:root {
  --bg: #F7F6F2;
  --surface: #FFFFFF;
  --border: #E2E0D8;
  --text: #1A1A18;
  --muted: #6B6A65;
  --accent: #2563EB;
  --accent-light: #EFF6FF;
  --accent-dark: #1d4ed8;
  --radius: 14px;
  --font-display: 'Space Grotesk', sans-serif;
  --font-body: 'Inter', sans-serif;
  --max-width: 1100px;
}

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  font-size: 1rem;
  line-height: 1.6;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* ── Header ── */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  display: flex;
  align-items: center;
  gap: 1rem;
  height: 60px;
}

.logo {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.03em;
  flex-shrink: 0;
}
.logo span { color: var(--accent); }

.main-nav {
  display: flex;
  gap: 0.25rem;
  margin-left: auto;
  flex-wrap: wrap;
}
.main-nav a {
  text-decoration: none;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--muted);
  padding: 0.4rem 0.9rem;
  border-radius: 8px;
  transition: background 0.15s, color 0.15s;
}
.main-nav a:hover { background: var(--accent-light); color: var(--accent); }

.nav-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.4rem;
  cursor: pointer;
  margin-left: auto;
  padding: 0.25rem;
  color: var(--text);
}

/* ── Footer ── */
.site-footer {
  margin-top: 4rem;
  border-top: 1px solid var(--border);
  padding: 2rem 0;
}
.footer-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--muted);
}
.footer-inner nav { display: flex; gap: 1.5rem; }
.footer-inner a { color: var(--muted); text-decoration: none; }
.footer-inner a:hover { color: var(--accent); }

/* ── Cards ── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
}
.card:hover { box-shadow: 0 4px 20px rgba(0,0,0,0.06); }

/* ── Forms ── */
label {
  display: block;
  font-size: 0.8rem;
  font-weight: 500;
  color: var(--muted);
  margin-bottom: 0.3rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  padding: 0.65rem 0.9rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-family: var(--font-body);
  font-size: 1rem;
  color: var(--text);
  background: var(--bg);
  margin-bottom: 1rem;
  transition: border-color 0.15s;
  appearance: none;
}
input:focus, select:focus {
  outline: none;
  border-color: var(--accent);
}

input[type="range"] {
  width: 100%;
  accent-color: var(--accent);
  margin-bottom: 1rem;
}

.row-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }

.result-box {
  background: var(--accent-light);
  border-radius: 10px;
  padding: 1rem 1.25rem;
  margin-top: 0.5rem;
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--accent);
  min-height: 52px;
  word-break: break-word;
}
.result-box small {
  display: block;
  font-size: 0.8rem;
  font-weight: 400;
  color: #5b84d6;
  margin-top: 0.25rem;
}

/* ── Homepage ── */
.hero {
  text-align: center;
  padding: 4rem 1rem 2.5rem;
}
.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1.1;
  margin-bottom: 1rem;
}
.hero p {
  color: var(--muted);
  font-size: 1.1rem;
  max-width: 520px;
  margin: 0 auto 2rem;
}

.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1.25rem;
  padding: 2rem 0 3rem;
}

.category-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  text-decoration: none;
  color: var(--text);
  display: block;
  transition: box-shadow 0.2s, transform 0.2s;
}
.category-card:hover {
  box-shadow: 0 6px 24px rgba(0,0,0,0.09);
  transform: translateY(-2px);
}
.category-card .cat-icon {
  font-size: 2rem;
  margin-bottom: 0.75rem;
  display: block;
}
.category-card h2 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 0.4rem;
}
.category-card p {
  font-size: 0.875rem;
  color: var(--muted);
  margin-bottom: 1rem;
}
.category-card .calc-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.category-card .calc-list li {
  font-size: 0.825rem;
  color: var(--accent);
}

/* ── Category page ── */
.cat-page { padding: 2rem 0 4rem; }
.cat-header { margin-bottom: 2rem; }
.cat-header h1 {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}
.cat-header p { color: var(--muted); font-size: 1rem; }

.calc-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1.25rem;
}
.calc-card-link {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  text-decoration: none;
  color: var(--text);
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  transition: box-shadow 0.2s, transform 0.2s;
}
.calc-card-link:hover {
  box-shadow: 0 4px 20px rgba(0,0,0,0.08);
  transform: translateY(-2px);
}
.calc-card-link .icon { font-size: 1.5rem; flex-shrink: 0; margin-top: 2px; }
.calc-card-link h2 { font-size: 1rem; font-weight: 600; margin-bottom: 0.25rem; }
.calc-card-link p { font-size: 0.85rem; color: var(--muted); }

/* ── Calculator page ── */
.calc-page { padding: 2rem 0 4rem; }

/* ← Limita ancho y centra páginas individuales */
.calc-container {
  max-width: 900px !important;
  padding-left: 2.5rem !important;
  padding-right: 2.5rem !important;
}

.breadcrumb {
  font-size: 0.8rem;
  color: var(--muted);
  margin-bottom: 1.5rem;
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  align-items: center;
}
.breadcrumb a { color: var(--accent); text-decoration: none; }
.breadcrumb a:hover { text-decoration: underline; }

.calc-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 2rem;
  align-items: start;
}

.calc-main h1 {
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 0.5rem;
}
.calc-intro {
  color: var(--muted);
  margin-bottom: 1.5rem;
  font-size: 0.975rem;
}

.calc-sidebar { display: flex; flex-direction: column; gap: 1.25rem; }

.sidebar-card h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}
.sidebar-card h3 {
  font-size: 0.9rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
}
.sidebar-card p { font-size: 0.875rem; color: var(--muted); line-height: 1.6; }

.related-list { list-style: none; display: flex; flex-direction: column; gap: 0.4rem; }
.related-list a {
  font-size: 0.875rem;
  color: var(--accent);
  text-decoration: none;
}
.related-list a:hover { text-decoration: underline; }

details { border-bottom: 1px solid var(--border); padding: 0.6rem 0; }
details:last-child { border-bottom: none; }
summary {
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  list-style: none;
  padding-right: 1rem;
  position: relative;
}
summary::after {
  content: '+';
  position: absolute;
  right: 0;
  top: 0;
  color: var(--muted);
}
details[open] summary::after { content: '−'; }
details p { font-size: 0.85rem; color: var(--muted); margin-top: 0.5rem; padding-left: 0.5rem; }

/* ── Keyboard (calc básica) ── */
.kbd-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.5rem;
  margin-top: 1rem;
}
.kbd-grid button {
  padding: 0.85rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  font-size: 1.05rem;
  font-family: var(--font-body);
  cursor: pointer;
  transition: background 0.1s;
  color: var(--text);
}
.kbd-grid button:hover { background: #e8e6e0; }
.kbd-grid button.op { background: var(--accent-light); color: var(--accent); }
.kbd-grid button.eq { background: var(--accent); color: #fff; border-color: var(--accent); }
.kbd-grid button.clr { background: #FEF2F2; color: #DC2626; border-color: #FECACA; }

.calc-display {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1rem 1.25rem;
  text-align: right;
  margin-bottom: 0.75rem;
}
.calc-display .expr { font-size: 0.85rem; color: var(--muted); min-height: 1.2em; }
.calc-display .val {
  font-size: 2rem;
  font-weight: 600;
  font-family: var(--font-display);
  word-break: break-all;
}

/* ── BMI bar ── */
.bmi-bar {
  height: 8px;
  border-radius: 99px;
  background: linear-gradient(to right, #3B82F6 0%, #22C55E 30%, #EAB308 60%, #EF4444 85%, #7C3AED 100%);
  position: relative;
  margin: 0.75rem 0 0.3rem;
}
.bmi-marker {
  position: absolute;
  top: -5px;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: var(--text);
  border: 3px solid white;
  transform: translateX(-50%);
  transition: left 0.4s;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .calc-layout { grid-template-columns: 1fr; }
  .calc-sidebar { order: -1; }
  .main-nav { display: none; }
  .main-nav.open {
    display: flex;
    flex-direction: column;
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: 1rem;
    z-index: 99;
  }
  .nav-toggle { display: block; }
  .row-2 { grid-template-columns: 1fr; }
}