* {
  box-sizing: border-box;
  font-family: 'Cairo', sans-serif;
}

body {
  margin: 0;
  background: #F4F6F8;
  color: #1E293B;
  padding-bottom: 80px;
}

/* Header */
.header {
  background: linear-gradient(135deg, #C62828, #E53935);
  padding: 25px 20px;
  color: white;
}

.header-content {
  display: flex;
  align-items: center;
  gap: 15px;
}

.logo {
  width: 70px;
}

.header h1 {
  margin: 0;
  font-size: 20px;
}

.header p {
  margin: 5px 0 0;
  font-size: 14px;
  opacity: 0.95;
}

/* Section Title */
.section-title {
  padding: 20px;
}

.section-title h2 {
  margin: 0;
}

.section-title p {
  margin: 6px 0 0;
  color: #64748B;
  font-size: 14px;
}

/* Subjects Grid */
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px;
  padding: 0 20px;
}

.subject-card {
  background: white;
  border-radius: 14px;
  padding: 16px;
  box-shadow: 0 6px 18px rgba(0,0,0,.06);
  transition: transform .2s;
}

.subject-card:hover {
  transform: translateY(-3px);
}

.subject-card h3 {
  margin: 0;
  font-size: 16px;
}

.subject-card p {
  margin: 8px 0;
  font-size: 13px;
  color: #475569;
}

.subject-card span {
  font-size: 13px;
  color: #C62828;
  font-weight: 600;
}

/* Locked Subject */
.subject-card.locked {
  opacity: 0.6;
}

/* Bottom Navigation */
.bottom-nav {
  position: fixed;
  bottom: 0;
  width: 100%;
  background: white;
  border-top: 1px solid #E5E7EB;
  display: flex;
  justify-content: space-around;
  padding: 10px 0;
}

.bottom-nav div {
  font-size: 12px;
  color: #94A3B8;
  text-align: center;
}

.bottom-nav .active {
  color: #C62828;
  font-weight: 600;
}