/* YS Institute — Zero-Dependency Styles */
:root {
  --primary: #0D7377;
  --primary-dark: #0A5C60;
  --secondary: #C19A6B;
  --bg: #FAFAF8;
  --surface: #F5F3EF;
  --heading: #1A1A1A;
  --body: #4A4A48;
  --muted: #8A8A88;
  --border: #E5E3DF;
  --font-sans: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-serif: 'Merriweather', Georgia, 'Times New Roman', serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  color: var(--body);
  background: var(--bg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

h1, h2, h3, h4 {
  font-family: var(--font-serif);
  color: var(--heading);
  line-height: 1.25;
  font-weight: 700;
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.site-header {
  background: rgba(250,250,248,0.92);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.logo {
  font-family: var(--font-serif);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--heading);
  letter-spacing: -0.02em;
}
.logo span { color: var(--primary); }
.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}
.nav-links a {
  color: var(--body);
  font-weight: 500;
  font-size: 0.95rem;
  position: relative;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--primary);
  transition: width 0.2s;
}
.nav-links a:hover { color: var(--primary); text-decoration: none; }
.nav-links a:hover::after { width: 100%; }

/* Hero */
.hero {
  padding: 6rem 0 5rem;
  text-align: center;
  background: linear-gradient(180deg, var(--surface) 0%, var(--bg) 100%);
}
.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  margin-bottom: 1rem;
  letter-spacing: -0.03em;
}
.hero .subheadline {
  font-size: 1.2rem;
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto 2.25rem;
}
.hero-cta {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.2s ease;
  border: 2px solid transparent;
  cursor: pointer;
  font-family: var(--font-sans);
}
.btn-primary {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}
.btn-primary:hover {
  background: var(--primary-dark);
  border-color: var(--primary-dark);
  text-decoration: none;
  transform: translateY(-1px);
}
.btn-secondary {
  background: transparent;
  color: var(--primary);
  border-color: var(--primary);
}
.btn-secondary:hover {
  background: var(--primary);
  color: #fff;
  text-decoration: none;
  transform: translateY(-1px);
}

/* Sections */
.section { padding: 5rem 0; }
.section-alt { background: var(--surface); }
.section-title {
  font-size: 2rem;
  margin-bottom: 0.75rem;
  text-align: center;
}
.section-lead {
  text-align: center;
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto 2.5rem;
  font-size: 1.05rem;
}

/* Cards */
.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}
.card {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 2rem;
  transition: box-shadow 0.25s, transform 0.25s;
}
.card:hover {
  box-shadow: 0 12px 32px rgba(0,0,0,0.06);
  transform: translateY(-3px);
}
.card h3 {
  font-size: 1.2rem;
  margin-bottom: 0.5rem;
  color: var(--heading);
}
.card p {
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.6;
}
.card-icon {
  width: 44px;
  height: 44px;
  border-radius: 10px;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  margin-bottom: 1rem;
  color: var(--primary);
}

/* About */
.about-hero { background: var(--surface); }
.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 1.5rem;
  text-align: center;
  margin: 3rem 0;
}
.stat h3 {
  font-size: 2.75rem;
  color: var(--primary);
  font-family: var(--font-sans);
  font-weight: 700;
}
.stat p {
  color: var(--muted);
  font-size: 0.9rem;
  margin-top: 0.25rem;
}

.values {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 1.5rem;
  margin-top: 2.5rem;
}
.value {
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.75rem;
}
.value h4 {
  font-size: 1.1rem;
  margin-bottom: 0.5rem;
  color: var(--primary);
}
.value p {
  font-size: 0.92rem;
  color: var(--muted);
  line-height: 1.6;
}

/* Programs */
.program {
  display: flex;
  gap: 1.5rem;
  align-items: flex-start;
  background: #fff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1.75rem;
  margin-bottom: 1.25rem;
  transition: box-shadow 0.2s, transform 0.2s;
}
.program:hover {
  box-shadow: 0 8px 24px rgba(0,0,0,0.05);
  transform: translateY(-2px);
}
.program-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  flex-shrink: 0;
  color: var(--primary);
}
.program-body { flex: 1; }
.program h3 { font-size: 1.15rem; margin-bottom: 0.35rem; }
.program p { color: var(--muted); font-size: 0.95rem; line-height: 1.6; }
.program-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--primary);
  background: rgba(13,115,119,0.08);
  padding: 0.25rem 0.6rem;
  border-radius: 999px;
  margin-top: 0.75rem;
}

/* Contact */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: start;
}
.contact-info h3 {
  font-size: 1.25rem;
  margin-bottom: 1.25rem;
}
.contact-list { list-style: none; }
.contact-list li {
  margin-bottom: 1rem;
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
  color: var(--body);
}
.contact-list .icon {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  background: var(--surface);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  flex-shrink: 0;
  color: var(--primary);
}
.contact-list .label {
  color: var(--muted);
  font-size: 0.85rem;
  display: block;
  margin-bottom: 0.15rem;
}
.contact-list strong {
  color: var(--heading);
  font-weight: 500;
}

/* Form */
.form-group { margin-bottom: 1.25rem; }
.form-group label {
  display: block;
  font-weight: 600;
  font-size: 0.9rem;
  margin-bottom: 0.4rem;
  color: var(--heading);
}
.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fff;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  color: var(--heading);
  transition: border-color 0.2s, box-shadow 0.2s;
}
.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(13,115,119,0.08);
}
.form-group textarea {
  min-height: 120px;
  resize: vertical;
}

/* Footer */
.site-footer {
  background: var(--heading);
  color: #A0A09E;
  padding: 3rem 0 2rem;
  margin-top: 3rem;
}
.site-footer .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}
.site-footer .logo { color: #fff; }
.site-footer p { font-size: 0.88rem; }
.site-footer a { color: var(--secondary); }
.site-footer a:hover { color: #fff; }

/* Mobile */
.mobile-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  color: var(--heading);
  cursor: pointer;
}

@media (max-width: 720px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 68px;
    left: 0;
    right: 0;
    background: rgba(250,250,248,0.98);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 1rem;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 8px 24px rgba(0,0,0,0.04);
  }
  .nav-links.open { display: flex; }
  .mobile-toggle { display: block; }
  .hero { padding: 3.5rem 0 3rem; }
  .section { padding: 3rem 0; }
  .cards { grid-template-columns: 1fr; }
  .program { flex-direction: column; }
  .contact-grid { grid-template-columns: 1fr; gap: 2rem; }
  .site-footer .container { flex-direction: column; text-align: center; }
}

/* Utility */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}