/* ============================================
   CHEMISTRY OLYMPIAD TUTORING — SHARED STYLES
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=DM+Serif+Display:ital@0;1&family=DM+Sans:wght@300;400;500;600&display=swap');

/* --- Variables --- */
:root {
  --navy:     #0d1b2a;
  --teal:     #1a7f8e;
  --teal-lt:  #22a8bc;
  --gold:     #c9a84c;
  --cream:    #f5f0e8;
  --white:    #ffffff;
  --gray:     #6b7280;
  --gray-lt:  #e8eaed;

  --font-display: 'DM Serif Display', Georgia, serif;
  --font-body:    'DM Sans', system-ui, sans-serif;

  --radius: 6px;
  --transition: 0.25s ease;
  --max-w: 1100px;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  background: var(--cream);
  color: var(--navy);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

img { max-width: 100%; display: block; }
a  { color: inherit; text-decoration: none; }

/* --- Navigation --- */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--navy);
  padding: 0 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
  box-shadow: 0 2px 12px rgba(0,0,0,0.25);
}

.nav-logo {
  font-family: var(--font-display);
  font-size: 1.25rem;
  color: var(--white);
  letter-spacing: 0.01em;
}

.nav-logo span { color: var(--gold); }

.nav-links {
  display: flex;
  gap: 0.25rem;
  list-style: none;
}

.nav-links a {
  font-size: 0.9rem;
  font-weight: 500;
  color: rgba(255,255,255,0.75);
  padding: 0.5rem 1.1rem;
  border-radius: var(--radius);
  letter-spacing: 0.03em;
  transition: background var(--transition), color var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  background: rgba(255,255,255,0.1);
  color: var(--white);
}

.nav-links a.active {
  color: var(--gold);
}

/* --- Page Header Banner --- */
.page-banner {
  background: linear-gradient(135deg, var(--navy) 0%, #1a3a50 100%);
  color: var(--white);
  padding: 5rem 2rem 4rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.page-banner::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse at 70% 50%, rgba(26,127,142,0.25) 0%, transparent 65%);
  pointer-events: none;
}

.page-banner h1 {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  line-height: 1.15;
  position: relative;
}

.page-banner p {
  margin-top: 1rem;
  font-size: 1.1rem;
  color: rgba(255,255,255,0.7);
  max-width: 560px;
  margin-left: auto;
  margin-right: auto;
  position: relative;
}

/* --- Container --- */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 2rem;
}

/* --- Section --- */
section {
  padding: 5rem 2rem;
}

section h2 {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  margin-bottom: 1rem;
  color: var(--navy);
}

section h2 .accent { color: var(--teal); }

/* --- Button --- */
.btn {
  display: inline-block;
  font-family: var(--font-body);
  font-size: 0.95rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 0.75rem 1.8rem;
  border-radius: var(--radius);
  cursor: pointer;
  border: 2px solid transparent;
  transition: background var(--transition), color var(--transition), transform 0.15s;
}

.btn:hover { transform: translateY(-2px); }

.btn-primary {
  background: var(--teal);
  color: var(--white);
}
.btn-primary:hover { background: var(--teal-lt); }

.btn-outline {
  background: transparent;
  border-color: var(--navy);
  color: var(--navy);
}
.btn-outline:hover { background: var(--navy); color: var(--white); }

/* --- Footer --- */
footer {
  margin-top: auto;
  background: var(--navy);
  color: rgba(255,255,255,0.5);
  text-align: center;
  padding: 2rem;
  font-size: 0.85rem;
}

footer a { color: var(--gold); }

/* --- Divider --- */
.divider {
  width: 60px;
  height: 3px;
  background: var(--gold);
  margin: 1.25rem 0 1.75rem;
  border-radius: 2px;
}

/* --- Responsive Nav --- */
@media (max-width: 600px) {
  nav { padding: 0 1rem; }
  .nav-logo { font-size: 1rem; }
  .nav-links a { padding: 0.45rem 0.75rem; font-size: 0.85rem; }
  section { padding: 3rem 1.25rem; }
}