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

html {
  scroll-behavior: smooth;
}

body {
  font-family: Arial, Helvetica, sans-serif;
  background: #f5f7fb;
  color: #1f2937;
  line-height: 1.6;
}

.hero {
  min-height: 30vh;
  background: linear-gradient(135deg, #0f172a 0%, #1e3a8a 55%, #2563eb 100%);
  color: white;
  padding-bottom: 5px;
}

.navbar {
  max-width: 1200px;
  margin: auto;
  padding: 24px 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-weight: bold;
  font-size: 1.2rem;
}

.nav-links {
  display: flex;
  gap: 18px;
  list-style: none;
}

.nav-links a {
  color: white;
  text-decoration: none;
  font-size: 0.95rem;
  opacity: 0.9;
}

.nav-links a:hover {
  opacity: 1;
  text-decoration: underline;
}

.menu-toggle {
  display: none;
  font-size: 1.8rem;
  background: none;
  border: none;
  color: white;
  cursor: pointer;
}

.hero-content {
  max-width: 900px;
  margin: auto;
  padding: 100px 20px 30px;
  text-align: center;
}

.badge {
  display: inline-block;
  background: rgba(255,255,255,0.18);
  padding: 8px 18px;
  border-radius: 999px;
  margin-bottom: 20px;
}

.hero h1 {
  font-size: clamp(2.2rem, 5vw, 4.3rem);
  margin-bottom: 20px;
}

.hero p {
  font-size: 1.2rem;
  max-width: 760px;
  margin: 0 auto 30px;
}

.btn-primary {
  display: inline-block;
  background: #f97316;
  color: white;
  padding: 13px 24px;
  border-radius: 12px;
  text-decoration: none;
  border: none;
  cursor: pointer;
  font-size: 1rem;
  font-weight: bold;
}

.btn-primary:hover {
  background: #ea580c;
}

main {
  max-width: 1100px;
  margin: -60px auto 0;
  padding: 0 20px 60px;
}

.intro-card,
.topic,
.quiz-section {
  background: white;
  border-radius: 22px;
  padding: 32px;
  margin-bottom: 28px;
  box-shadow: 0 15px 35px rgba(15, 23, 42, 0.08);
}

.intro-card h2,
.topic h2,
.quiz-section h2 {
  color: #1e3a8a;
  margin-bottom: 12px;
}

.topic {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 24px;
}

.topic-number {
  width: 72px;
  height: 72px;
  background: #dbeafe;
  color: #1d4ed8;
  border-radius: 22px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-weight: bold;
  font-size: 1.5rem;
}

.example-box,
.warning-box,
.activity {
  margin-top: 22px;
  padding: 22px;
  border-radius: 18px;
}

.example-box {
  background: #eff6ff;
  border-left: 6px solid #2563eb;
}

.warning-box {
  background: #fff7ed;
  border-left: 6px solid #f97316;
}

.activity {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
}

.activity h3 {
  color: #c2410c;
  margin-bottom: 8px;
}

textarea {
  width: 100%;
  min-height: 95px;
  margin-top: 12px;
  padding: 14px;
  border: 1px solid #cbd5e1;
  border-radius: 14px;
  resize: vertical;
  font-size: 1rem;
}

.grid-list,
.daily-grid,
.cards {
  display: grid;
  gap: 16px;
  margin-top: 22px;
}

.grid-list {
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
}

.grid-list div,
.daily-grid div,
.card {
  background: #f8fafc;
  padding: 18px;
  border-radius: 16px;
  border: 1px solid #e2e8f0;
}

.cards {
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.card h3 {
  color: #1e40af;
  margin-bottom: 8px;
}

.daily-grid {
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
}

ul {
  margin-left: 20px;
  margin-top: 10px;
}

.question {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  padding: 18px;
  border-radius: 16px;
  margin: 18px 0;
}

.question label {
  display: inline-block;
  margin-right: 20px;
  margin-top: 8px;
}

.quiz-result {
  margin-top: 20px;
  font-size: 1.1rem;
  font-weight: bold;
}

.top-button {
  position: fixed;
  bottom: 25px;
  right: 25px;
  width: 46px;
  height: 46px;
  border-radius: 50%;
  border: none;
  background: #1d4ed8;
  color: white;
  font-size: 1.4rem;
  cursor: pointer;
  display: none;
}

footer {
  text-align: center;
  padding: 28px;
  background: #0f172a;
  color: white;
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }

  .nav-links {
    position: absolute;
    top: 75px;
    left: 0;
    right: 0;
    background: #0f172a;
    flex-direction: column;
    padding: 20px;
    display: none;
  }

  .nav-links.active {
    display: flex;
  }

  .topic {
    grid-template-columns: 1fr;
  }

  .topic-number {
    width: 64px;
    height: 64px;
  }

  main {
    margin-top: -35px;
  }
}