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

body {
  background: #f6f8fc;
  color: #0f172a;
  font-family: Arial, sans-serif;
}

a {
  text-decoration: none;
}

.container {
  width: min(1150px, 92%);
  margin: auto;
}

/* NAVBAR */
.navbar {
  background: #ffffff;
  border-bottom: 1px solid #e5e7eb;
  position: sticky;
  top: 0;
  z-index: 1000;
}

.nav-wrap {
  min-height: 66px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 800;
  color: #0f172a;
}

.logo img {
  width: 34px;
  height: 34px;
  object-fit: contain;
  border-radius: 6px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 22px;
  list-style: none;
}

.nav-links a {
  color: #475569;
  font-weight: 700;
  font-size: 0.92rem;
}

.nav-links a:hover {
  color: #2563eb;
}

.nav-btn {
  background: #2563eb;
  color: #fff !important;
  padding: 8px 16px;
  border-radius: 999px;
}

/* HERO */
.hero {
  background: linear-gradient(135deg, #e0f2fe, #eef2ff, #f8fafc);
  padding: 65px 0;
  text-align: center;
}

.tag {
  display: inline-block;
  background: #ffffff;
  color: #2563eb;
  padding: 8px 14px;
  border-radius: 999px;
  font-weight: 800;
  margin-bottom: 14px;
  box-shadow: 0 8px 20px rgba(37, 99, 235, 0.08);
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 3.2rem);
  margin-bottom: 10px;
}

.hero p {
  color: #64748b;
  font-size: 1rem;
}

/* NOTES */
.notes-section {
  padding: 55px 0;
}

.section-title {
  text-align: center;
  margin-bottom: 35px;
}

.section-title h2 {
  font-size: 2rem;
  margin-bottom: 8px;
}

.section-title p {
  color: #64748b;
}

.notes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.note-card {
  background: #ffffff;
  border: 1px solid #e5e7eb;
  border-radius: 22px;
  padding: 24px;
  box-shadow: 0 10px 25px rgba(15, 23, 42, 0.06);
  transition: 0.3s ease;
}

.note-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 18px 35px rgba(15, 23, 42, 0.12);
}

.chapter-no {
  width: 52px;
  height: 52px;
  background: linear-gradient(135deg, #2563eb, #7c3aed);
  color: #fff;
  border-radius: 16px;
  display: grid;
  place-items: center;
  font-weight: 900;
  margin-bottom: 16px;
}

.note-card h3 {
  font-size: 1.08rem;
  margin-bottom: 10px;
  line-height: 1.4;
}

.note-card p {
  color: #64748b;
  font-size: 0.9rem;
  margin-bottom: 18px;
}

.card-actions {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.view-btn,
.download-btn,
.disabled-btn {
  padding: 9px 14px;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 800;
}

.view-btn {
  background: #eff6ff;
  color: #2563eb;
}

.download-btn {
  background: #2563eb;
  color: #fff;
}

.disabled-btn {
  background: #f1f5f9;
  color: #64748b;
}

.coming {
  opacity: 0.8;
}

/* RESPONSIVE */
@media (max-width: 900px) {
  .notes-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 650px) {
  .nav-wrap {
    gap: 12px;
  }

  .logo span {
    font-size: 0.9rem;
  }

  .logo img {
    width: 30px;
    height: 30px;
  }

  .nav-links {
    gap: 10px;
  }

  .nav-links a {
    font-size: 0.78rem;
  }

  .nav-btn {
    padding: 6px 10px;
  }

  .notes-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
  }

  .note-card {
    padding: 14px;
    border-radius: 16px;
  }

  .chapter-no {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    font-size: 0.85rem;
  }

  .note-card h3 {
    font-size: 0.85rem;
  }

  .note-card p {
    font-size: 0.72rem;
  }

  .card-actions {
    flex-direction: column;
  }

  .view-btn,
  .download-btn,
  .disabled-btn {
    text-align: center;
    font-size: 0.7rem;
    padding: 8px 10px;
  }
}