/* ── DESIGN TOKENS ── */
:root {
  --navy:       #1B2E4B;
  --navy-mid:   #243A5E;
  --navy-light: #2E4A75;
  --gold:       #C9882A;
  --gold-hover: #B57620;
  --gold-light: #F0B85A;
  --white:      #FFFFFF;
  --off-white:  #F7F6F2;
  --gray-100:   #F0F0EB;
  --gray-200:   #E2E1DB;
  --gray-500:   #9CA3AF;
  --gray-600:   #6B7280;
  --text:       #111827;
  --text-light: #4B5563;
  --max-w:      1200px;
  --radius:     10px;
}

/* ── RESET ── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: 'Inter', system-ui, sans-serif;
  color: var(--text);
  background: var(--white);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
img { display: block; max-width: 100%; }
a { color: inherit; text-decoration: none; }
ul { list-style: none; }

/* ── NAV ── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 200;
  background: rgba(255,255,255,0.96);
  border-bottom: 1px solid var(--gray-200);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
}
.nav-inner {
  max-width: var(--max-w); margin: 0 auto;
  padding: 0 2rem; height: 68px;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo { display: flex; flex-direction: column; line-height: 1.2; }
.nav-logo-name { font-size: 1rem; font-weight: 800; letter-spacing: -0.02em; color: var(--navy); }
.nav-logo-sub  { font-size: 0.65rem; font-weight: 500; letter-spacing: 0.12em; text-transform: uppercase; color: var(--gold); }
.nav-links { display: flex; align-items: center; gap: 2.25rem; list-style: none; }
.nav-links a {
  font-size: 0.8rem; font-weight: 600; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--text-light); transition: color 0.2s;
}
.nav-links a:hover, .nav-links a.active { color: var(--navy); }
.nav-contact {
  background: var(--navy) !important; color: var(--white) !important;
  padding: 0.45rem 1.1rem; border-radius: var(--radius);
  transition: background 0.2s !important;
}
.nav-contact:hover { background: var(--gold) !important; }

/* ── CLASS HERO ── */
.class-hero {
  background: var(--navy);
  padding: 9rem 2rem 5rem;
  position: relative; overflow: hidden;
}
.class-hero::before {
  content: 'π  ∑  √  ∞  ∫  Δ  θ  ≈  ≠  ≤  ÷  ×';
  position: absolute; top: 0; right: 0; bottom: 0;
  width: 45%; display: flex; align-items: center; padding-left: 3rem;
  font-size: 3.5rem; color: rgba(255,255,255,0.04);
  font-weight: 900; letter-spacing: 1.5rem; line-height: 2;
  pointer-events: none;
}
.hero-inner { max-width: var(--max-w); margin: 0 auto; position: relative; }
.breadcrumb {
  font-size: 0.75rem; font-weight: 500;
  color: rgba(255,255,255,0.4); margin-bottom: 1.5rem; letter-spacing: 0.04em;
}
.breadcrumb a { color: rgba(255,255,255,0.5); transition: color 0.2s; }
.breadcrumb a:hover { color: var(--gold-light); }
.breadcrumb .sep { margin: 0 0.5rem; }
.grade-badge {
  display: inline-block; background: var(--gold); color: var(--white);
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.14em;
  text-transform: uppercase; padding: 0.3rem 0.9rem;
  border-radius: 100px; margin-bottom: 1rem;
}
.class-hero h1 {
  font-size: clamp(2.75rem, 5vw, 4.5rem);
  font-weight: 900; letter-spacing: -0.04em;
  color: var(--white); line-height: 1.0; margin-bottom: 1rem;
}
.class-tagline {
  font-size: 1.1rem; color: rgba(255,255,255,0.6);
  max-width: 520px; line-height: 1.65;
}

/* ── SECTION COMMONS ── */
.section { padding: 5.5rem 2rem; }
.section-inner { max-width: var(--max-w); margin: 0 auto; }
.section-label {
  font-size: 0.7rem; font-weight: 700; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--gold);
  margin-bottom: 0.875rem; display: flex; align-items: center; gap: 0.5rem;
}
.section-label::before {
  content: ''; display: inline-block; width: 20px; height: 2px; background: var(--gold);
}
.section-h2 {
  font-size: clamp(1.75rem, 2.5vw, 2.5rem); font-weight: 800;
  letter-spacing: -0.03em; color: var(--navy); line-height: 1.1; margin-bottom: 1rem;
}
.section-p {
  font-size: 0.975rem; color: var(--text-light);
  line-height: 1.75; margin-bottom: 2.5rem; max-width: 600px;
}

/* ── OVERVIEW ── */
.overview-section { background: var(--white); }
.overview-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 4.5rem; align-items: start;
}
.about-class-text .section-h2 { margin-bottom: 1.25rem; }
.about-class-text p {
  font-size: 0.975rem; color: var(--text-light); line-height: 1.8; margin-bottom: 1rem;
}
.topics-list {
  background: var(--off-white); border-radius: 16px; padding: 2rem;
}
.topics-list h3 {
  font-size: 0.9rem; font-weight: 700; color: var(--navy); letter-spacing: -0.01em;
  margin-bottom: 1.25rem; padding-bottom: 0.875rem; border-bottom: 2px solid var(--gray-200);
}
.topics-list li {
  display: flex; gap: 0.875rem; align-items: flex-start;
  padding: 0.875rem 0; border-bottom: 1px solid var(--gray-200);
}
.topics-list li:last-child { border-bottom: none; }
.topic-num {
  width: 24px; height: 24px; background: var(--navy); color: var(--white);
  border-radius: 50%; display: flex; align-items: center; justify-content: center;
  font-size: 0.62rem; font-weight: 700; flex-shrink: 0; margin-top: 0.1rem;
}
.topic-content h4 { font-size: 0.875rem; font-weight: 600; color: var(--navy); margin-bottom: 0.2rem; }
.topic-content p  { font-size: 0.78rem; color: var(--text-light); line-height: 1.5; }

/* ── REAL WORLD ── */
.rw-section { background: var(--off-white); }
.rw-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 1.5rem; margin-bottom: 3rem;
}
.rw-card {
  background: var(--white); border-radius: 14px; padding: 2rem;
  border: 1px solid var(--gray-200);
  transition: box-shadow 0.2s, transform 0.2s;
}
.rw-card:hover {
  box-shadow: 0 10px 28px rgba(27,46,75,0.09);
  transform: translateY(-3px);
}
.rw-emoji { font-size: 2rem; margin-bottom: 1rem; }
.rw-card h3 { font-size: 0.975rem; font-weight: 700; color: var(--navy); margin-bottom: 0.5rem; }
.rw-card p  { font-size: 0.85rem; color: var(--text-light); line-height: 1.65; }
.careers-row h3 {
  font-size: 0.72rem; font-weight: 700; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--text-light); margin-bottom: 0.875rem;
}
.career-pills { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.career-pill {
  background: var(--navy); color: var(--white);
  font-size: 0.78rem; font-weight: 600;
  padding: 0.4rem 1rem; border-radius: 100px;
}

/* ── CALENDAR ── */
.cal-section { background: var(--white); }
.cal-layout {
  display: grid; grid-template-columns: 320px 1fr; gap: 3rem; align-items: start;
}

/* Calendar widget */
.cal-widget {
  background: var(--off-white); border-radius: 16px;
  overflow: hidden; border: 1px solid var(--gray-200);
}
.cal-head {
  background: var(--navy); padding: 0.875rem 1.25rem;
  display: flex; align-items: center; justify-content: space-between;
}
.cal-nav-btn {
  background: rgba(255,255,255,0.1); border: none; color: var(--white);
  width: 30px; height: 30px; border-radius: 6px; cursor: pointer;
  font-size: 1rem; display: flex; align-items: center; justify-content: center;
  transition: background 0.2s; line-height: 1;
}
.cal-nav-btn:hover { background: var(--gold); }
.cal-month-label { font-size: 0.88rem; font-weight: 700; color: var(--white); }
.cal-grid { display: grid; grid-template-columns: repeat(7, 1fr); }
.cal-dow {
  text-align: center; font-size: 0.58rem; font-weight: 700;
  letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--text-light); padding: 0.6rem 0;
  background: rgba(0,0,0,0.04);
}
.cal-day {
  position: relative; text-align: center;
  padding: 0.55rem 0.15rem 0.45rem; font-size: 0.8rem;
  cursor: default; transition: background 0.15s; user-select: none;
}
.cal-day.has-plan { cursor: pointer; font-weight: 700; color: var(--navy); }
.cal-day.has-plan:hover { background: rgba(201,136,42,0.12); }
.cal-day.cal-weekend { color: var(--gray-500); }
.cal-day.cal-weekend.has-plan { color: var(--navy); }
.cal-day-num {
  display: block; width: 26px; height: 26px; line-height: 26px;
  margin: 0 auto; border-radius: 50%; font-size: 0.78rem;
}
.cal-day.today .cal-day-num {
  background: var(--navy); color: var(--white); font-weight: 700;
}
.plan-dot {
  width: 5px; height: 5px; background: var(--gold);
  border-radius: 50%; margin: 2px auto 0;
}
.cal-empty { padding: 0.55rem 0; }

/* Lesson list */
.lesson-list-wrap h3 {
  font-size: 1rem; font-weight: 700; color: var(--navy); margin-bottom: 0.3rem;
}
.lesson-month-sub {
  font-size: 0.78rem; color: var(--text-light); margin-bottom: 1.5rem; line-height: 1.5;
}
.lesson-item {
  display: flex; gap: 1rem; align-items: flex-start;
  padding: 0.875rem 0.5rem; border-bottom: 1px solid var(--gray-200);
  border-radius: 6px; transition: background 0.3s;
}
.lesson-item:last-child { border-bottom: none; }
.lesson-item.highlighted { background: rgba(201,136,42,0.08); }
.lesson-day-badge {
  min-width: 40px; height: 40px; background: var(--navy); color: var(--white);
  border-radius: 8px; display: flex; align-items: center; justify-content: center;
  font-size: 0.82rem; font-weight: 700; flex-shrink: 0;
}
.lesson-item-content .lesson-title {
  font-size: 0.875rem; font-weight: 600; color: var(--navy); margin-bottom: 0.25rem;
}
.lesson-item-content a {
  font-size: 0.75rem; font-weight: 600; color: var(--gold);
  letter-spacing: 0.04em; transition: color 0.15s;
}
.lesson-item-content a:hover { color: var(--gold-hover); }
.no-lessons {
  font-size: 0.875rem; color: var(--text-light);
  font-style: italic; padding: 1rem 0; line-height: 1.6;
}

/* ── FOOTER ── */
.footer {
  background: #0D1821; padding: 1.75rem 2rem;
  display: flex; align-items: center; justify-content: space-between;
  flex-wrap: wrap; gap: 1rem;
}
.footer-copy { font-size: 0.78rem; color: rgba(255,255,255,0.35); }
.footer-copy a { color: var(--gold-light); }
.footer-links { display: flex; gap: 1.75rem; }
.footer-links a {
  font-size: 0.75rem; font-weight: 600; letter-spacing: 0.06em;
  text-transform: uppercase; color: rgba(255,255,255,0.35); transition: color 0.2s;
}
.footer-links a:hover { color: var(--gold); }

/* ── MOBILE ── */
@media (max-width: 900px) {
  .overview-grid { grid-template-columns: 1fr; gap: 2rem; }
  .cal-layout { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .section { padding: 3.5rem 1.5rem; }
  .class-hero { padding: 7rem 1.5rem 3.5rem; }
  .footer { flex-direction: column; text-align: center; }
  .footer-links { justify-content: center; }
}
@media (max-width: 600px) {
  .rw-grid { grid-template-columns: 1fr; }
  .class-hero h1 { font-size: 2.5rem; }
  .cal-widget { width: 100%; }
}